JP2002374224A - Ofdm signal communication system, ofdm signal transmitting device and ofdm signal receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an OFDM signal communication system used, in broadband mobile communication or the like that achieves stable operation under severe frequency selective fading environments and provides high quality. SOLUTION: The OFDM signal communication system which is provided with an OFDM signal transmitting device and an OFDM signal receiving device, transmits OFDM signals over the same radio frequency from N transmitting antennas 5, has an N×N inverse matrix computer 13 for computing an N×N inverse matrix, constituted by propagation coefficients for respective propagation paths between each of the N transmitting antennas 5 and N receiving antennas 8, and a subcarrier demodulator 14, which separates the signals of the respective propagation paths, based on the obtained inverse matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to orthogonal frequency division multiplexing (OFDM:
Orthogonal Frequency Division Multiplexing) signal transmission system. More specifically, in a multipath fading environment, OFDM signal transmission that achieves dramatic frequency utilization efficiency using a plurality of transmission antennas and a plurality of reception antennas and performs high-quality, large-capacity, high-speed signal transmission About the system.

[0002]

2. Description of the Related Art For example, in a broadband mobile communication, available frequency bands are limited, and in order to support full-scale multimedia, high frequency use efficiency equivalent to that of fixed microwave communication must be achieved. As required,
There is a need to overcome severe frequency selective fading and achieve high quality transmission.

The following methods have been proposed for realizing large-capacity, high-speed mobile communication using a limited frequency band. That is, using multiple transmission antennas and multiple reception antennas, MIMO (Multiple Input Multipl
e Output) channel, the transmitting side transmits a plurality of channels using the same frequency, and the receiving side separates each channel by an equalizer and an interference canceller to increase the capacity.

In a MIMO Rayleigh fading channel formed when N transmitting antennas are used on the transmitting side and M (M ≧ N) receiving antennas are used on the receiving side, the capacity limit of Shannon is given by the following equation. Can be

(Equation 1) Here, H is an M × N matrix, and its element (i, j) is a transfer function between the i-th transmitting antenna and the j-th receiving antenna. I is an M × N eigenvalue matrix, and ρ is an average SNR. Also, det is det
ermination, * indicates a complex conjugate. When M = N, the lower limit of the capacity is given by the following equation.

(Equation 2) Here, χ ² _2k shows the effect of the k-th order diversity. That is, the capacity of a MIMO channel is N times that of a single channel. As described above, if interference cancellation can be ideally performed in the MIMO channel, large-capacity and high-speed transmission can be realized in wideband mobile communication. FIG. 12 shows a configuration example of a conventional transmission / reception apparatus in this MIMO channel. This corresponds to N transmitting antennas 110-1 to 110-N.
Is a configuration example of a transmission / reception apparatus that performs space-time equalization using N reception antennas 111-1 to 111-N. On the transmission side, transmission information is encoded in encoders 101-1 to 101-N. , Interleavers 102-1 to 102-N and N modulators 103-1 to 103-N
And then transmitted.

On the other hand, N interference cancellers 1 are provided on the receiving side.
14-1 to 114-N and N equalizers 115-1 to 115-11
5-N. The reception signal of the reception antenna 111-1 is first equalized by the equalizer 115-1, then deinterleaved by the deinterleaver 116-1, and input to the decoder 118-1. In the decoder 118-1, decoding corresponding to the encoding in the encoder 101-1 is performed.

[0006] By taking the difference between the output of the decoder 118-1 and the output of the deinterleaver 116-1, an interference component is extracted. This interference component is generated by the interleaver 117-
1 and its output is fed back to the equalizer 115-1 as control information. On the other hand, the equalizer 115-1
Is subtracted from the interference component, which is the output of the interleaver 117-1, and is again input to the deinterleaver 116-1.

By the repetition processing here, the decoder 11
The reliability of the output of 8-1 is increased. Receiving antenna 11
In 1-1, all N transmission signals from transmission antennas 110-1 to 110-N are combined and received. In the interference canceller 114-1, the received signal of the receiving antenna 111-1 in which all the N transmission signals are combined is given by
The output of decoder 118-1 is subtracted.

Thus, the signal transmitted by transmitting antenna 110-1 is removed from the signal received by receiving antenna 111-1, and transmitted antennas 110-2 to 110-
A signal obtained by combining N (N-1) transmission signals.
This signal is input to the next equalizer 115-2. In the equalizer 115-2, similarly to the processing in the system of the equalizer 115-1, after equalization by the equalizer 115-2, de-interleaving by the de-interleaver 116-2 and decoding by the decoder 118-
2 is input.

[0009] In the decoder 118-2, the encoder 101-2
The decoding corresponding to the encoding in is performed. Decoder 118-
The interference component is extracted by taking the difference between the output of Deinterleaver 116-2 and the output of deinterleaver 116-2. This interference component is input to interleaver 117-2, and its output is fed back to equalizer 115-2 as control information. On the other hand, the interference component that is the output of the interleaver 117-2 is subtracted from the output of the equalizer 115-2, and the result is input to the deinterleaver 116-2 again.

By the repetition processing here, the decoder 11
The reliability of the output of 8-2 is increased. Interference canceller 1
At 14-2, based on the input from the decoder 118-1,
Subtract the output of decoder 118-2. Thereby, the signal transmitted by transmission antenna 110-2 is further removed, and (N-1) of transmission antennas 110-3 to 110-N are removed.
The transmission signal is a combined signal.

This signal is input to the next equalizer 115-3. In this manner, the interference signal decoded by the decoder 118 is sequentially removed by the interference canceller 114, and the output of the interference canceller 114- (N-1) finally becomes the transmission signal of the transmission antenna 110-N, and is equalized. Vessel 115-N
, And the deinterleaver 116-N and the decoder 118
Decoded with -N. This operation is performed using the receiving antenna 111-
2, 111-3,..., 111-N.

The decoding results from the decoders 118-1 to 118N repeat a series of processing, and the final outputs of the N decoders are sent to the converter 119, where they are converted into serial received data. This means that the transmitting antenna 110-
This is equivalent to estimating a transfer function in each path between i and the receiving antenna 111-j by an equalizer, and performing interference cancellation based on the estimated transfer function.

Therefore, the operation of the equalizer is N ×
N paths are equalized, and based on the result, (N
-1) It is necessary to perform xN interference cancellation.

[0014]

In the transmission / reception apparatus in the conventional MIMO channel as shown in FIG. 12, N equalizers are required for each reception system corresponding to the reception antenna of the reception apparatus. Further, when performing wideband transmission in a severe multipath fading environment, frequency-selective fading occurs, and it is necessary to identify the frequency characteristics of amplitude and phase generated by fading in each system in a very short time with high accuracy.

However, in an actual fading environment, the number and intensity of arriving delayed waves, so-called delay profiles, vary, and it is extremely difficult to realize an equalizer effective for all such environments. . For this reason, MI
Although the transmission / reception device in the MO channel is feasible in an environment close to a Gaussian channel such as fixed communication, the transmission / reception device in the MIMO channel requires extremely large signal processing capability in a MIMO channel in which severe multipath fading occurs. Implementation of the device was difficult.

Further, in the conventional transmission / reception apparatus for the MIMO channel as shown in FIG. 12, the amplitude / phase frequency characteristic distorted by the multiplex wave fading on the fading propagation path is estimated and subtracted from the output of the decoder 118-1. As a result, interference cancellation is performed. in this case,
Each equalizer is required to have high estimation accuracy for the amplitude / phase frequency characteristics. If equalization accuracy cannot be achieved,
This is because interference cancellation by the interference canceller cannot be performed sufficiently, resulting in residual interference noise.

However, it is difficult for the equalizer to equalize the frequency characteristics of the amplitude and phase with high accuracy, so that the signal-to-interference-noise ratio tends to deteriorate. Furthermore,
When assuming a system for performing wireless communication between a fixed base station and a mobile terminal, providing a complicated processing function on the mobile terminal side leads to an increase in hardware scale and power consumption in the mobile terminal. Therefore, a problem arises in miniaturization and cost reduction of the mobile terminal.

In view of the above circumstances, it is an object of the present invention to achieve stable operation under severe frequency-selective fading environment and improve quality in an OFDM signal transmission system used for wideband mobile communication and the like. And

[0019]

The above-mentioned problems are solved by the invention described in the claims.

That is, claim 1 includes an OFDM signal transmitting apparatus including a plurality of N transmitting antennas, and an OFDM signal receiving apparatus including a plurality of N receiving antennas, wherein the OFDM signal transmitting apparatus is the same radio. An OFDM signal transmission system for transmitting an OFDM signal of a frequency from the N transmission antennas, wherein a transmission coefficient in each signal transmission path between each of the N transmission antennas and each of the N reception antennas Inverse matrix operation means for calculating an inverse matrix of a matrix composed of N × N elements having components as: components, and based on the inverse matrix obtained by the inverse matrix operation means, each of the N transmission antennas Interference canceling means for separating signals on each signal transmission path between each of the N receiving antennas.

Claim 2 is a system comprising a plurality of N transmitting antennas and a plurality of N receiving antennas,
OFDM connected for each transmitting antenna, using the same radio frequency, and operating based on symbol timing
A frequency converter connected to a modulator and a transmission antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; A common OFDM symbol timing is supplied to at least one OFDM signal transmitting apparatus connected to the OFDM modulator and having means for multiplexing the transmission information signal and the pilot signal, and to all of the OFDM modulators related to the OFDM signal transmitting apparatus. And a local oscillator that supplies a common local oscillation signal to all of the frequency converters of the OFDM signal transmitting apparatus, and is connected to each receiving antenna, and demodulates a radio frequency reception signal using the local oscillation frequency. Frequency converter for converting the frequency to a frequency suitable for the frequency converter and an OFDM modulator respectively connected to the frequency converter For all combinations of a transmitting antenna and a receiving antenna, a fast Fourier transformer that operates based on a timing signal for receiving a pilot signal transmitted in response to a receiving antenna, and a pilot signal having a known pilot amplitude and phase for all combinations of a transmitting antenna and a receiving antenna. Inverse matrix operation means for normalizing the signal amplitude and phase to measure a transfer coefficient, calculating and storing an inverse matrix for a matrix related to each subcarrier, and each received OFDM signal output from the fast Fourier transformer, and At least one OFDM signal receiving apparatus having a subcarrier demodulating means for taking a product of a subcarrier and the inverse matrix and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal, and the OFDM signal receiving apparatus A local oscillator for supplying a common local oscillation signal to all of the frequency converters; Characterized in that it is constituted by the timing signal generating means for receiving a pilot signal transmitted in response to each OFDM modulator according to the DM signal receiving apparatus at the receiving antenna.

A third aspect of the present invention is a transmitting apparatus used in the OFDM signal transmission system according to the second aspect, wherein the transmitting apparatus is connected to each transmitting antenna, uses the same radio frequency,
A frequency converter that is connected to an OFDM modulator that operates based on symbol timing and a transmission antenna and converts an output of the OFDM modulator to a radio frequency using a local oscillation frequency; and a known pilot corresponding to each of the OFDM modulators. A signal generating means and means for multiplexing the transmission information signal and the pilot signal with each of the OFDM modulators.

According to a fourth aspect of the present invention, there is provided a receiving apparatus for use in the OFDM signal transmission system according to the second aspect, wherein the receiving apparatus is connected to each receiving antenna and uses a local oscillation frequency to demodulate a received signal of a radio frequency. Frequency converter for converting the frequency to
The reception amplitude and phase of a pilot signal for a fast Fourier transformer operating based on a timing signal for receiving a pilot signal transmitted corresponding to each FDM modulator by a reception antenna and for all combinations of a transmission antenna and a reception antenna Is normalized by a known pilot signal amplitude / phase to measure a transfer coefficient, and an inverse matrix operation means for calculating and storing an inverse matrix for a matrix related to each subcarrier and each received OFDM signal as an output of the fast Fourier transformer. And a subcarrier demodulating means for calculating a product of the inverse matrix and a signal relating to an arbitrary subcarrier and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal.

According to a fifth aspect of the present invention, in the OFDM signal transmission system according to the second aspect, two transmission antennas using mutually orthogonal polarizations as transmission antennas and two reception antennas using mutually orthogonal polarizations as reception antennas. Use Claim 6 is a transmitting apparatus used in the OFDM signal transmission system according to claim 5, wherein the transmitting apparatus is connected to each transmitting antenna, uses the same radio frequency,
A frequency converter that is connected to an OFDM modulator that operates based on symbol timing and a transmission antenna and converts an output of the OFDM modulator to a radio frequency using a local oscillation frequency; and a known pilot corresponding to each of the OFDM modulators. A signal generating means and means for multiplexing the transmission information signal and the pilot signal with each of the OFDM modulators.

A seventh aspect of the present invention is a receiving apparatus used in the OFDM signal transmission system according to the fifth aspect, wherein the receiving apparatus is connected to each receiving antenna and uses a local oscillation frequency to demodulate a radio frequency received signal. Frequency converter for converting the frequency to
The reception amplitude and phase of a pilot signal for a fast Fourier transformer operating based on a timing signal for receiving a pilot signal transmitted corresponding to each FDM modulator by a reception antenna and for all combinations of a transmission antenna and a reception antenna Is normalized by a known pilot signal amplitude / phase to measure a transfer coefficient, and an inverse matrix operation means for calculating and storing an inverse matrix for a matrix related to each subcarrier and each received OFDM signal as an output of the fast Fourier transformer. And a subcarrier demodulating means for calculating a product of the inverse matrix and a signal relating to an arbitrary subcarrier and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal.

[0026] Claim 8 provides a plurality of N transmitting antennas,
A system comprising a plurality of N receiving antennas, connected to each transmitting antenna, using the same radio frequency, and operating based on symbol timing.
A frequency converter connected to a DM modulator and a transmitting antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; A means connected to each OFDM modulator for multiplexing the transmission information signal and the pilot signal, an error correction encoder for performing error correction encoding on the transmission information, and an output of the error correction device are output from the OFDM modulator and the subcarriers. At least one OFDM signal transmission device having an interleaver for performing interleaving by combination, and an OFDM signal according to the OFDM signal transmission device
A means for supplying a common OFDM symbol timing to all of the modulators, a local oscillator for supplying a common local oscillation signal to all of the frequency converters of the OFDM signal transmitting apparatus, a local oscillator connected to each of the receiving antennas, A frequency modulator for converting a received signal of a radio frequency into a frequency suitable for demodulation using an oscillation frequency, and a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator by a receiving antenna. For a fast Fourier transformer operating based on a timing signal for reception and all combinations of a transmitting antenna and a receiving antenna, the transfer coefficient is measured by normalizing the received amplitude and phase of the pilot signal with the known pilot signal amplitude and phase. Inverse matrix operation means for calculating and storing an inverse matrix for a matrix related to each subcarrier, and a high speed Each received OF serving output of Rie converter
A subcarrier demodulation means for taking the product of the inverse matrix and a DM signal relating to an arbitrary subcarrier and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal, and demodulation outputs of the subcarrier demodulation means. A deinterleaver that performs the reverse operation of the interleaver, and at least one OFDM signal receiving device that has an error correction decoder that decodes the error correction code; and a local common to all of the frequency converters related to the OFDM signal receiving device. A local oscillator for supplying an oscillating signal, and Oss according to the OFDM signal receiving apparatus.
It is characterized by comprising timing signal generating means for receiving a pilot signal transmitted corresponding to each FDM modulator by a receiving antenna.

A ninth aspect of the present invention is a transmitting apparatus used in the OFDM signal transmission system according to the eighth aspect, wherein the transmitting apparatus is connected to each transmitting antenna, uses the same radio frequency,
A frequency converter connected to an OFDM modulator operating based on symbol timing and a transmission antenna and converting an output of the OFDM modulator into a radio frequency using a local oscillation frequency; and a known pilot corresponding to each of the OFDM modulators Means for generating a signal, means for multiplexing a transmission information signal and the pilot signal connected to each of the OFDM modulators, and an output of an error correction encoder and an error correction device for performing error correction coding on the transmission information. It has an interleaver that performs interleaving by a combination of an OFDM modulator and a subcarrier.

According to a tenth aspect of the present invention, there is provided a receiving apparatus used in the OFDM signal transmission system according to the eighth aspect, wherein the receiving apparatus is connected to each of the receiving antennas and uses a local oscillation frequency to demodulate a received signal of a radio frequency. Frequency converter, and a fast Fourier transformer and a transmitting antenna connected to the frequency converter and operated based on a timing signal for receiving a pilot signal transmitted corresponding to each OFDM modulator by a receiving antenna For all combinations of antennas and receiving antennas, the transmission coefficient is measured by normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, and the inverse matrix for the matrix related to each subcarrier is calculated and stored. Each of the received OFDM signals output from the matrix operation means and the fast Fourier transformer, Taking the product of the inverse matrix as according to Yaria, amplitude and of the subcarrier of each transmission OFDM signal
It has a subcarrier demodulating means for outputting a phase, a deinterleaver for receiving the demodulated output of the subcarrier demodulating means as input and performing an operation reverse to that of the interleaver, and an error correction decoder for decoding the error correction code.

According to an eleventh aspect, in the OFDM signal transmission system according to the eighth aspect, two transmission antennas using mutually orthogonal polarizations as transmission antennas and two reception antennas using mutually orthogonal polarizations as reception antennas. use. Claim 12 is an OFD according to claim 11
A transmission device used in an M signal transmission system,
OFDM connected for each transmitting antenna, using the same radio frequency, and operating based on symbol timing
A frequency converter connected to a modulator and a transmission antenna for converting an output of the OFDM modulator into a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; A means connected to each OFDM modulator for multiplexing the transmission information signal and the pilot signal, an error correction encoder for performing error correction encoding on the transmission information, and an output of the error correction device are output from the OFDM modulator and the subcarriers. It has an interleaver that performs interleaving by combination.

The thirteenth aspect of the present invention relates to the OFDM according to the eleventh aspect.
A receiving device used in a signal transmission system, which is connected to each receiving antenna, and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency, and a frequency converter and a frequency converter, respectively. For all combinations of a fast Fourier transformer and a transmission antenna and a reception antenna, which operate based on a timing signal for receiving a pilot signal transmitted corresponding to each OFDM modulator by a reception antenna, and the reception amplitude of the pilot signal Matrix operation means for normalizing the phase and phase with a known pilot signal amplitude and phase to measure a transfer coefficient, calculating and storing an inverse matrix for a matrix related to each subcarrier, and each reception OFDM as an output of a fast Fourier transformer Take the product of the signal and any of the subcarriers and the inverse matrix, and A subcarrier demodulator for outputting the amplitude and phase of the subcarrier of the FDM signal, a deinterleaver for receiving the demodulated output of the subcarrier demodulator as input, and performing an operation opposite to the interleaver, and an error correction decoder for decoding the error correction code Having.

A fourteenth aspect of the present invention is a system including a plurality of N transmitting antennas and a plurality of N receiving antennas, wherein the system is connected to each of the transmitting antennas, uses the same radio frequency, and controls symbol timing. O based on
A frequency converter connected to an FDM modulator and a transmission antenna for converting the output of the OFDM modulator to a radio frequency using a local oscillation frequency, and switching and transmitting a signal obtained by serial-parallel conversion of a transmission information signal or the same transmission information signal And a means for generating a known pilot signal corresponding to each OFDM modulator, a means connected to each OFDM modulator for multiplexing a transmission information signal and the pilot signal, and an error for the transmission information. At least one OFDM signal transmission device having an error correction encoder that performs correction encoding and an interleaver that interleaves the output of the error corrector with a combination of an OFDM modulator and a subcarrier;
A means for supplying a common OFDM symbol timing to all of the OFDM modulators according to the OFDM signal transmitting apparatus, a local oscillator to supply a common local oscillation signal to all of the frequency converters according to the OFDM signal transmitting apparatus, A frequency converter that is connected to each receiving antenna and converts a received signal of a radio frequency to a frequency suitable for demodulation using a local oscillation frequency, and is connected to the frequency converter and transmitted corresponding to each OFDM modulator. For a fast Fourier transformer that operates based on a timing signal for receiving a pilot signal at a receiving antenna, and for all combinations of a transmitting antenna and a receiving antenna, the received amplitude and phase of the pilot signal are normalized with a known pilot signal amplitude and phase. To measure the transfer coefficient, and calculate the inverse matrix for the matrix related to each subcarrier. Inverse matrix operation means for calculating and storing the received OFDM signal output from the fast Fourier transformer, the product of any subcarrier and the inverse matrix, and the amplitude of the subcarrier of each transmission OFDM signal・
A sub-carrier demodulating means for outputting a phase, a de-interleaver for performing an operation reverse to the interleaver with a demodulated output of the sub-carrier demodulating means as an input, an error correcting decoder for decoding the error correcting code, and an arbitrary sub carrier of a transmission OFDM signal. A means for measuring the reception quality of the output of the subcarrier demodulation means and a case where the transmission side outputs a signal obtained by serial-to-parallel conversion of the transmission information signal, and outputs a subcarrier demodulation output and transmits the same transmission information signal. At least one OFDM signal receiving device having a switch for adding a subcarrier demodulation output or outputting a higher reception level among the subcarrier demodulation outputs;
A local oscillator that supplies a common local oscillation signal to all of the frequency converters according to the signal receiving device, and a pilot signal transmitted corresponding to each OFDM modulator according to the OFDM signal receiving device is received by a receiving antenna. And a timing signal generating means.

The fifteenth aspect of the present invention provides the OFDM according to the fourteenth aspect.
A transmission device used in a signal transmission system, wherein the transmission device is connected to each transmission antenna, uses the same radio frequency, operates based on symbol timing, and is connected to a transmission antenna and outputs the OFDM modulator. A frequency converter for converting to a radio frequency using a local oscillation frequency, a signal for serial-to-parallel conversion of a transmission information signal or a switch for switching and transmitting the same transmission information signal, and a known pilot corresponding to each OFDM modulator Means for generating a signal, means for multiplexing the transmission information signal and the pilot signal connected to each of the OFDM modulators, and an error correction encoder for performing error correction coding on the transmission information, and an output of the error corrector. It has an interleaver that performs interleaving by a combination of an OFDM modulator and subcarriers.

The sixteenth aspect of the present invention provides the OFDM according to the fourteenth aspect.
A receiving device used in a signal transmission system, which is connected to each receiving antenna, and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency, and a frequency converter and a frequency converter, respectively. For all combinations of a fast Fourier transformer and a transmission antenna and a reception antenna, which operate based on a timing signal for receiving a pilot signal transmitted corresponding to each OFDM modulator by a reception antenna, and the reception amplitude of the pilot signal Matrix operation means for normalizing the phase and phase with a known pilot signal amplitude and phase to measure a transfer coefficient, calculating and storing an inverse matrix for a matrix related to each subcarrier, and each reception OFDM as an output of a fast Fourier transformer Take the product of the signal and any of the subcarriers and the inverse matrix, and A subcarrier demodulator for outputting the amplitude and phase of the subcarrier of the FDM signal, a deinterleaver for performing an operation reverse to the interleaver with a demodulated output of the subcarrier demodulator as an input, and an error correction decoder for decoding the error correction code; Means for measuring the reception quality of the output of the subcarrier demodulation means relating to any subcarrier of the transmission OFDM signal, and outputting a subcarrier demodulation output when transmitting a signal obtained by serial-to-parallel conversion of the transmission information signal on the transmission side; When transmitting the same transmission information signal, a switch is provided for adding the subcarrier demodulation outputs or outputting the subcarrier demodulation output with the higher reception level.

The seventeenth aspect of the present invention provides the OFDM according to the fourteenth aspect.
In a signal transmission system, two transmission antennas using mutually orthogonal polarizations are used as transmission antennas, and two reception antennas using mutually orthogonal polarizations are used as reception antennas. Claim 18 is an OF according to claim 17.
A transmitting device used in a DM signal transmission system, which is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a DM modulator and a transmission antenna for converting the output of the OFDM modulator to a radio frequency using a local oscillation frequency; And a means for generating a known pilot signal corresponding to each of the OFDM modulators, a means for multiplexing the transmission information signal and the pilot signal connected to each of the OFDM modulators, and an error for the transmission information. An error correction encoder that performs correction encoding and an interleaver that interleaves the output of the error corrector with a combination of an OFDM modulator and subcarriers.

In the nineteenth aspect, the OFDM according to the seventeenth aspect is provided.
A receiving device used in a signal transmission system, which is connected to each receiving antenna, and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency, and a frequency converter and a frequency converter, respectively. For all combinations of a fast Fourier transformer and a transmission antenna and a reception antenna, which operate based on a timing signal for receiving a pilot signal transmitted corresponding to each OFDM modulator by a reception antenna, and the reception amplitude of the pilot signal Matrix operation means for normalizing the phase and phase with a known pilot signal amplitude and phase to measure a transfer coefficient, calculating and storing an inverse matrix for a matrix related to each subcarrier, and each reception OFDM as an output of a fast Fourier transformer Take the product of the signal and any of the subcarriers and the inverse matrix, and A subcarrier demodulator for outputting the amplitude and phase of the subcarrier of the FDM signal, a deinterleaver for receiving the demodulated output of the subcarrier demodulator as input, and performing an operation opposite to the interleaver, and an error correction decoder for decoding the error correction code And means for measuring the reception quality of the output of the subcarrier demodulation means relating to any subcarrier of the transmission OFDM signal, and outputting the subcarrier demodulated output when transmitting a signal obtained by serial-parallel conversion of the transmission information signal on the transmission side. In the case where the same transmission information signal is transmitted, there is provided a switch for adding the subcarrier demodulation output or outputting the subcarrier demodulation output having the higher reception level.

A twentieth aspect of the present invention comprises an OFDM signal transmitting apparatus including a plurality of N transmitting antennas, and an OFDM signal receiving apparatus including a plurality of N receiving antennas.
An OFDM signal transmission system in which an M signal transmitting apparatus transmits an OFDM signal of the same radio frequency from the N transmitting antennas, wherein the OFDM signal transmitting apparatus includes a known OFDM signal corresponding to each of the N transmitting antennas. A pilot signal generating means for generating N types of pilot signals, and OFD transmission data of
N data conversion means for converting into M symbols;
An inverse matrix receiving means for receiving information on the inverse matrix transmitted from the FDM signal receiving apparatus; and for each subcarrier of each OFDM symbol generated by the data conversion means, the inverse matrix obtained by the inverse matrix receiving means. A pre-interference canceling unit for performing multiplication, and N types of pilot signals output from the pilot signal generating unit are multiplexed with each of N signals output from the pre-interference canceling unit.
Multiplexing means, N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the N multiplexing means, and a common signal for all of the N fast inverse Fourier transform means. Symbol timing generating means for providing OFDM symbol timing, N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency, and all of the N transmitting frequency converting means And a local oscillation means for transmitting which provides a common local oscillation signal to the OFDM signal receiving apparatus, and the OFDM signal receiving apparatus converts a radio frequency reception signal received by the N reception antennas into a frequency suitable for demodulation. Receiving frequency converting means, receiving local oscillating means for providing a common local oscillation signal to all of the N receiving frequency converting means, and the N receiving frequency converting means. N fast Fourier transform means for performing a Fourier transform process on each of the N systems of received signals output by the frequency transform means, and N demodulations for transforming the OFDM symbols output from the fast Fourier transform means into bit strings Means, timing signal generating means for generating a timing signal necessary to extract from the received signal the N pilot signals transmitted through each of the N transmitting antennas, and an output of the fast Fourier transform means The amplitude and phase are detected for each sub-carrier from the received N pilot signals appearing in each of the sub-carriers, and based on the detected amplitude and phase, each of the N transmission antennas and the N reception antennas corresponds to each combination. Matrix computing means for computing an inverse matrix of a matrix composed of N × N elements of transfer coefficients, And inverse matrix information transmitting means for transmitting the inverse matrix information to the OFDM signal transmitting apparatus.

A twenty-first aspect of the present invention includes an OFDM signal transmitting apparatus including a plurality of N transmitting antennas, and an OFDM signal receiving apparatus including a plurality of N receiving antennas.
An OFDM signal transmission device used in an OFDM signal transmission system in which an M signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas, wherein a known signal corresponding to each of the N transmission antennas is provided. A pilot signal generating means for generating N kinds of pilot signals, and OFD transmission data of
N data conversion means for converting into M symbols;
An inverse matrix receiving means for receiving information on the inverse matrix transmitted from the FDM signal receiving apparatus; and for each subcarrier of each OFDM symbol generated by the data conversion means, the inverse matrix obtained by the inverse matrix receiving means. A pre-interference canceling unit for performing multiplication, and N types of pilot signals output from the pilot signal generating unit are multiplexed with each of N signals output from the pre-interference canceling unit.
Multiplexing means, N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the N multiplexing means, and a common signal for all of the N fast inverse Fourier transform means. Symbol timing generating means for providing OFDM symbol timing, N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency, and all of the N transmitting frequency converting means And a local oscillation means for transmission for providing a common local oscillation signal to the transmission means.

A twenty-second aspect of the present invention comprises an OFDM signal transmitting device including a plurality of N transmitting antennas, and an OFDM signal receiving device including a plurality of N receiving antennas.
An OFDM signal receiving apparatus for use in an OFDM signal transmission system in which an M signal transmitting apparatus transmits OFDM signals of the same radio frequency from the N transmitting antennas,
N receiving frequency converting means for converting received signals of radio frequencies received by the receiving antennas into a frequency suitable for demodulation, and a common local oscillation signal is provided to all of the N receiving frequency converting means. Local oscillation means for reception, N fast Fourier transform means for performing a Fourier transform process on each of N received signals output from the N frequency transform means for reception, and an output from the fast Fourier transform means N demodulation means for converting the OFDM symbol to be converted into a bit string, and a timing signal necessary for extracting N pilot signals transmitted via each of the N transmission antennas from a received signal. The amplitude and phase of the received N pilot signals appearing at the output of the timing signal generating means and the fast Fourier transform means are detected for each subcarrier. Then, based on the detected amplitude and phase, an inverse matrix of a matrix composed of transfer coefficients of N × N elements corresponding to each combination of the N transmitting antennas and the N receiving antennas is calculated. Inverse matrix operation means, and information of the inverse matrix obtained by the inverse matrix operation means
An inverse matrix information transmitting means for transmitting to the FDM signal transmitting apparatus is provided.

[0039] The twenty-third aspect of the present invention comprises an OFDM signal transmitting apparatus including a plurality of N transmitting antennas, and an OFDM signal receiving apparatus including a plurality of N receiving antennas.
An OFDM signal transmission system in which an M signal transmitting apparatus transmits an OFDM signal of the same radio frequency from the N transmitting antennas, wherein the OFDM signal transmitting apparatus includes a known OFDM signal corresponding to each of the N transmitting antennas. A pilot signal generating means for generating N types of pilot signals, and OFD transmission data of
N data conversion means for converting into M symbols;
Information receiving means for receiving received information of a pilot signal transmitted from an FDM signal receiving apparatus; and amplitude and phase of N pilot signals received by the OFDM signal receiving apparatus based on the information received by the information receiving means. A matrix composed of N × N elements of transmission coefficients corresponding to the respective combinations of the N transmission antennas and the N reception antennas based on the detected amplitude and phase. An inverse matrix operation means for calculating an inverse matrix of; and a pre-interference cancellation means for multiplying each subcarrier of each OFDM symbol generated by the data conversion means with the inverse matrix obtained by the inverse matrix operation means. Multiplexing N kinds of pilot signals output from the pilot signal generating means with each of the N signals output from the pre-interference canceling means. And an N-number of multiplexing means for said N
N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the multiplexing means, and symbol timing generating means for giving a common OFDM symbol timing to all of the N fast inverse Fourier transform means And N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transforming means into a radio frequency, and transmitting a local oscillation signal common to all of the N transmitting frequency converting means. A credit local oscillation means is provided,
The OFDM signal receiving apparatus includes: N reception frequency conversion units configured to convert a radio frequency reception signal received by the N reception antennas into a frequency suitable for demodulation; and the N reception frequency conversion units. And N fast Fourier transforms for performing a Fourier transform process on each of the N systems of received signals output by the N receive frequency conversion means. Means,
N demodulation means for converting an OFDM symbol output from the fast Fourier transform means into a bit string, and N demodulation means for extracting N pilot signals transmitted through each of the N transmission antennas from a received signal. A timing signal generating means for generating a necessary timing signal, and an amplitude and a phase of the received N pilot signals are detected for each subcarrier from an output of the fast Fourier transform means, and the detected information is transmitted to the OFDM signal transmitting apparatus. And an information transmitting means for transmitting the information to the user.

The twenty-fourth aspect of the present invention comprises an OFDM signal transmitting apparatus including a plurality of N transmitting antennas, and an OFDM signal receiving apparatus including a plurality of N receiving antennas.
An OFDM signal transmitting apparatus used in an OFDM signal transmission system in which an M signal transmitting apparatus transmits an OFDM signal of the same radio frequency from the N transmitting antennas,
Pilot signal generating means for generating known N types of pilot signals corresponding to each of the transmission antennas,
N data conversion means for converting each of the input N transmission data into an OFDM symbol;
Information receiving means for receiving information of a pilot signal transmitted from the M signal receiving apparatus; and amplitude and phase of N pilot signals received by the OFDM signal receiving apparatus based on the information received by the information receiving means. A matrix composed of N × N elements of transmission coefficients corresponding to the respective combinations of the N transmission antennas and the N reception antennas based on the detected amplitude and phase. An inverse matrix operation means for calculating an inverse matrix of; and a pre-interference cancellation means for multiplying each subcarrier of each OFDM symbol generated by the data conversion means with the inverse matrix obtained by the inverse matrix operation means. Multiplexing N kinds of pilot signals output from the pilot signal generating means with each of the N signals output from the pre-interference canceling means. Common to all N multiplexing means, N fast inverse Fourier transform means for performing inverse Fourier transform on the signals output from the N multiplexing means, and N fast inverse Fourier transform means Symbol timing generating means for providing OFDM symbol timing, N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency, and N transmitting frequency converting means. A local oscillation means for transmission which supplies a common local oscillation signal to all of them is provided.

The twenty-fifth aspect of the present invention comprises an OFDM signal transmitting apparatus including a plurality of N transmitting antennas, and an OFDM signal receiving apparatus including a plurality of N receiving antennas.
An OFDM signal receiving apparatus for use in an OFDM signal transmission system in which an M signal transmitting apparatus transmits OFDM signals of the same radio frequency from the N transmitting antennas,
N receiving frequency converting means for converting received signals of radio frequencies received by the receiving antennas into a frequency suitable for demodulation, and a common local oscillation signal is provided to all of the N receiving frequency converting means. Local oscillation means for reception, N fast Fourier transform means for performing a Fourier transform process on each of N received signals output from the N frequency transform means for reception, and an output from the fast Fourier transform means N demodulation means for converting the OFDM symbol to be converted into a bit string, and a timing signal necessary for extracting N pilot signals transmitted via each of the N transmission antennas from a received signal. From the outputs of the timing signal generating means and the fast Fourier transform means, the amplitude and phase of the received N pilot signals are detected for each subcarrier, and the detection is performed. Characterized in that the information is provided and an information transmitting means for transmitting to the OFDM signal transmitting device.

Claim 26 is claim 20 or claim 23
In the OFDM signal transmission system, the OFDM signal receiving device further includes at least one information transmitting antenna, and the OFDM signal transmitting device further includes at least one information receiving antenna. . 28. The OFDM signal transmitting apparatus including a plurality of N first sets of antennas and an OFDM signal receiving apparatus including a plurality of N second sets of antennas, wherein the OFDM signal receiving apparatus includes a plurality of N second sets of antennas.
An OFDM signal transmission system in which a DM signal transmitting apparatus transmits an OFDM signal of the same radio frequency from the N first sets of antennas, wherein the OFDM signal receiving apparatus includes: A pilot signal generating means for generating corresponding N kinds of known pilot signals, and an N fast inverse Fourier transform for the N kinds of pilot signals output from the pilot signal generating means.
Number of inverse fast Fourier transforming means, N number of transmitting frequency converting means for converting a signal output from the inverse fast Fourier transforming means into a radio frequency for transmission, and a radio signal received by the second set of antennas. N receiving frequency converting means for converting a received signal having a frequency into a frequency suitable for demodulation, and performing Fourier transform processing on each of the N receiving signals output from the N receiving frequency converting means. N fast Fourier transforming means, N demodulating means for converting an OFDM symbol output from the fast Fourier transforming means into a bit sequence, the N transmitting frequency transforming means and the N receiving frequency transforming means And a transmission / reception switch for switching between transmission and reception with respect to the N second sets of antennas. The OFDM signal transmitting apparatus includes N data converting means for converting each of the input N-system transmission data into an OFDM symbol, and wireless data transmitted from the OFDM signal receiving apparatus and received by the first set of antennas. N number of receiving frequency converting means for converting a pilot signal of a frequency into a frequency suitable for demodulation, N fast Fourier transforming means for performing Fourier transform on a signal output from the receiving frequency converting means, Timing signal generating means for generating, from a received signal output from the fast Fourier transform means, a timing signal necessary for extracting each of the N pilot signals transmitted through the second set of antennas; N pilots transmitted from the OFDM signal transmitting apparatus based on the signal extracted from the output of the Fourier transform means Detecting a degree in amplitude and phase for each subcarrier, on the basis of the detected amplitude and phase, said N first set of antennas and N second
Inverse matrix calculating means for calculating an inverse matrix of a matrix composed of N × N elements of transmission coefficients corresponding to each combination of antennas, and each OF generated by the data converting means
Pre-interference canceling means for multiplying each subcarrier of the DM symbol by the inverse matrix calculated by the inverse-matrix calculating means, and performing inverse Fourier transform on a signal output from the pre-interference canceling means. Fast inverse Fourier transform means, N transmission frequency transform means for converting the frequency of the signal output from the fast inverse Fourier transform means into a radio frequency, N transmission frequency transform means and N Local oscillation means for providing a common local oscillation signal to all of the reception frequency conversion means, and transmission / reception switching means for switching between transmission and reception for the N first set of antennas are provided.

The twenty-eighth aspect of the present invention relates to an OFDM signal transmitting apparatus including a plurality of N first sets of antennas, and a plurality of N second sets of antennas.
An OFDM signal receiving apparatus including a set of antennas, wherein the OFDM signal transmitting apparatus has the same radio frequency
OFD for transmitting signals from the N first set of antennas
An OFDM signal receiving apparatus for use in an M signal transmission system, comprising: pilot signal generating means for generating known N types of pilot signals corresponding to each of the first set of antennas; and N output from the pilot signal generating means. N inverse fast Fourier transform means for performing inverse fast Fourier transform on the pilot signal of the type, and N transmission frequencies for converting a signal output from the inverse fast Fourier transform means into a radio frequency for transmission Conversion means; N reception frequency conversion means for converting a radio frequency reception signal received by the second set of antennas into a frequency suitable for demodulation;
N fast Fourier transform means for performing a Fourier transform process on each of N received signals output from the N receive frequency transform means, and an OFDM symbol output from the fast Fourier transform means as a bit string. N demodulating means for converting, the N transmitting frequency converting means and N
Local oscillation means for providing a common signal to all of the reception frequency conversion means, and transmission / reception switching means for switching between transmission and reception for the N second sets of antennas.

A twenty-ninth aspect of the present invention provides an OFDM signal transmitting apparatus including a plurality of N first sets of antennas and a plurality of N second antennas.
An OFDM signal receiving apparatus including a set of antennas, wherein the OFDM signal transmitting apparatus has the same radio frequency
OFD for transmitting signals from the N first set of antennas
An OFDM signal transmission device used in an M signal transmission system, wherein each of N input transmission data is
N data conversion means for converting into a DM symbol, and N reception means for converting a radio frequency pilot signal transmitted from the OFDM signal receiving apparatus and received by the first set of antennas into a frequency suitable for demodulation. Frequency conversion means;
From the N fast Fourier transform means for performing Fourier transform on the signal output from the receiving frequency transform means, and the second signal from the received signal output from the fast Fourier transform means,
Based on a timing signal generating means for generating a timing signal necessary to extract each of the N pilot signals transmitted through the set of antennas, and a signal extracted from an output of the fast Fourier transform means, The OFD
The amplitude and phase of the N pilot signals transmitted from the M signal transmitting device are detected for each subcarrier, and based on the detected amplitude and phase, the N first set of antennas and the N second Inverse matrix calculating means for calculating an inverse matrix of a matrix composed of N × N elements of transmission coefficients corresponding to each combination of antennas, and each subcarrier of each OFDM symbol generated by the data converting means Against
A pre-interference canceling means for multiplying the inverse matrix calculated by the inverse matrix calculating means, N fast inverse Fourier transform means for performing an inverse Fourier transform on a signal output from the pre-interference canceling means, N transmitting frequency converting means for converting the frequency of a signal output from the fast inverse Fourier transforming means to a radio frequency, and common to all of the N transmitting frequency converting means and the N receiving frequency converting means. Local oscillation means for providing a local oscillation signal, and transmission / reception switching means for switching between transmission and reception for the N first set of antennas are provided.

(Operation) In the present invention, an OFDM system is used to realize a signal transmission system on a MIMO channel without using an equalizer. Then, instead of estimating the transfer function on the time axis by the equalizer, the transfer coefficient (amplitude / phase) for each subcarrier is directly measured using, for example, a pilot signal, and interference cancellation between OFDM signals is canceled for each subcarrier. To obtain the transfer coefficient for

Accordingly, since interference cancellation is performed for each subcarrier, interference cancellation can be easily and accurately performed. According to this system, feedback control is performed as in the case of using an equalizer. Since it is not necessary to perform this operation and the feedforward processing can be performed, a stable operation can be achieved even under a severe frequency selective fading environment.

The inverse matrix calculating means and the interference canceling means for separating the signals on the respective signal transmission paths may be arranged in one of the OFDM signal transmitting apparatus and the OFDM signal receiving apparatus. Claims 2 to 1
As for No. 9, it is assumed that the inverse matrix calculating means and the interference canceling means are arranged on the OFDM signal receiving apparatus side.

However, since the processing of the inverse matrix calculation means and the interference cancellation means is complicated, the provision of these functions increases the hardware scale of the apparatus and the power consumption. Therefore, it is not desirable to mount the inverse matrix calculating means and the interference canceling means on the mobile terminal.
Claims 20 to 29 assume that at least one of the inverse matrix calculating means and the interference canceling means is mounted on the OFDM signal transmitting apparatus side. For example, O
The FDM signal transmission device may be considered in association with a base station that manages a plurality of mobile terminals, and the OFDM signal reception device may be considered in association with each mobile terminal.
Therefore, problems such as downsizing of the mobile terminal and reduction of power consumption can be overcome.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows one embodiment of the invention according to claim 2. In this embodiment, the OFDM signal transmission system includes two or more N transmission antennas, N OFDM signal transmission devices connected to each antenna and using the same radio frequency, and N reception antennas, It is composed of N OFDM signal receiving devices connected to each antenna and using the same radio frequency.

The configuration and operation of the embodiment shown in FIG. 1 will be described in detail. In the present embodiment, N OFDM modulators 1-1 corresponding to N transmission antennas 5-1 to 5-N are used.
~ 1-N are arranged. OFDM modulator 1-1 to 1-N
Then, modulation of a subcarrier and inverse Fourier transform are performed. A common OFDM symbol timing is supplied from the OFDM symbol timing control circuit 2 to these OFDM modulators 1-1 to 1-N.

The transmission information signals T _{1 to} T _N are pilot signal generators for generating known pilot signals P ₁ , P ₂ ,..., P _N corresponding to the respective OFDM modulators 1-1 to 1-N. Pilot signals P _{1 to} P _N input from means 6-1 to 6- _N
And multiplexing means on the time axis by multiplexing means 7-1 to 7-N. The multiplexed signal is input to each of the OFDM modulators 1-1 to 1-N.

The pilot signal _Pi is transmitted to the transmitting antenna 5-
It is used to measure the transfer coefficient between i and the receiving antennas 8-1 to 8-N. These pilot signals and transmission information signals are multiplexed and input to N OFDM modulators 1-1 to 1-N, respectively. Since all of these OFDM modulators 1-1 to 1-N need to operate at a common OFDM symbol timing, the OFDM modulator
OFDM symbol timing common to all of 1 to 1-N is supplied from the OFDM symbol timing control circuit 2.

The modulated outputs of the OFDM modulators 1-1 to 1-N are converted into N frequency converters 3 to 3 for conversion to radio frequencies.
1-N. These frequency converters 3-1
３−3-N are supplied with a common local oscillation signal from a local oscillator 4. Thereby, the transmitting antennas 5-1 to 5-N
The phase noise and the frequency fluctuation of the OFDM signal transmitted from the same are all the same.

On the other hand, in the OFDM signal receiving apparatus,
Since a common local oscillation signal is supplied from the local oscillator 10 to the frequency converters 9-1 to 9-N, the received OFD
The phase noise and frequency fluctuation of the M signal are all the same. For this reason, since each transmission OFDM signal has a common frequency fluctuation, interference cancellation between each subcarrier and synchronous detection can be facilitated.

The OFDM signals frequency-converted by the frequency converters 3-1 to 3-N are respectively transmitted from the transmitting antennas 5-1 to 5-1.
5-N and transmitted to the OFDM signal receiving device. In the OFDM signal receiving apparatus, N receiving OFDM signals transmitted from the transmitting antennas 5-1 to 5-N are added as signals in space to each of the receiving antennas 8-.
1 to 8-N.

The received signal is transmitted to the frequency converters 9-1 to 9-1.
The frequency is converted to a frequency suitable for demodulation at 9-N, and the Fourier transform is performed at the fast Fourier transformers 11-1 to 11-N. Here, O of the OFDM signal to be Fourier-transformed
The FDM symbol timing is supplied from the OFDM symbol timing reproducing means 9 and is common to all.
As a method of realizing the OFDM symbol timing reproducing means 9, there are various methods such as transmitting a special preamble for symbol timing reproduction separately to reproduce the OFDM symbol timing. Transmission antenna 5-1
FIG. 2 shows an example of an OFDM modulated signal transmitted from 5-N. In the example of FIG. 2, the pilot signals P ₁ ,
P _2, ···, P _N are transmitted so as not to overlap each other on the time axis.

On the other hand, OFDM signals modulated by the transmission information signals T _{1 to} T _N are transmitted in a superimposed manner on the time axis.
Pilot signals P _1, P _2, ···, is P _N, the transmitting antenna 5
-I used to know the transfer function from the receiving antenna 8-j. Generally, if the pilot signals P _{1 to} P _N have the same amplitude for each subcarrier, the same processing may be performed for each subcarrier and each receiving antenna system, so that signal processing can be facilitated.

Using this pilot signal, OFDM
Since each subcarrier of the signal is a signal having a constant amplitude and a constant phase in the OFDM symbol, the transmission antenna 5-1
The transfer function from to the receiving antenna 8-i is obtained as follows. Pilot signal Pi transmitted from transmitting antenna 5-1 is received by receiving antennas 8-1 to 8-N. The received pilot signal is frequency-converted by frequency converters 9-1 to 9-N, and then sent to N fast Fourier transformers 11-1 to 11-N.

In fast Fourier transformers 11-1 to 11-N, received pilot signals are separated for each subcarrier. By detecting the amplitude and phase of each received subcarrier signal, the transfer function of each subcarrier can be measured as a complex number. The transfer function of the subcarrier transmitted from the transmitting antenna 5-i and received by the receiving antenna 8- _j is obtained as a complex number s _i , _j . Here, the complex numbers s _i and _j which are transfer functions for each subcarrier are referred to as transfer coefficients.

Assuming that the number of subcarriers of the OFDM signal is M, the transfer function from the transmitting antenna 5-i to the receiving antenna 8-j is a set of complex numbers s _i and _j for each subcarrier, that is, M complex numbers s _i. , _J. This transfer function is obtained by the product (N × N) of the number N of transmitting antennas and the number N of receiving antennas. That is, all the transmission antennas 5-1 to 5-N are represented by (M × N × N) complex numbers.
And the transfer function of the combination of the reception antennas 8-1 to 8-N.

Here, paying attention to one certain subcarrier, the transmission signals from the transmission antennas 5-1 to 5-N are represented by (t
_{1, t 2, ···, t} N), the signal received by the receiving antenna _{8-1~8-N (r 1, r} 2, ···, represented by r _N). i
The transfer coefficient of the subcarrier is set to
Expressed in with determinant S _i corresponding to the combination of 5-N and the receiving antennas 8-1 to 8-N, it can be expressed as a matrix equation (N × N) element. This determinant S _i is given by the following equation.

(Equation 3) Focusing on the i-th subcarrier, the receiving antenna 8-
The received signals (r ₁ , r ₂ ,...,
r _N), the transmission signal transmitted by the transmission antennas _{5-1~5-N (t 1, t} 2, ···, is expressed by the following equation using the t _N) and the matrix equation S _i.

(Equation 4) In the receiving antennas 8-1 to 8-N, the transmitting antenna 5-1
Since OFDM signal transmitted from the to 5-N are received by superimposing, in the order to demodulate these, the received signal _{(r 1, r 2, ···} , r N) from the original transmission signal (T ₁ ,
t ₂ ,..., t _N ). From the received signals (r ₁ , r ₂ ,..., R _N ), the transmission signals (t ₁ , t ₂ ,.
· To restore the t _N) computes the inverse matrix S _i ^-1 of S _i for each subcarrier may be by computing the following formula for each subcarrier.

(Equation 5) In this way, in the inverse matrix calculating means 13, N transmitting antennas 5-1 to 5-N and N receiving antennas 8-1 to 8-
For each combination of N, the received amplitude and phase of the received pilot signal are normalized by the amplitude and phase of the known pilot signal, and an (N × N) matrix having a complex number as a transfer coefficient as an element for each i-th subcarrier An expression _Si is obtained by measurement, and its inverse matrix S _i ^-1 is calculated and stored.

Using the inverse matrix S _i ^-1 obtained for each i-th subcarrier, the subcarrier demodulation means 14
((R ₁ , r _i2 ,..., R _iN ) which is the i-th subcarrier of each received OFDM signal output from the N fast Fourier transformers 11-1 to 11 -N. _i1 , r _i2 , _...
.., R _iN ) × S _i ^-1 ) are calculated. As a result, the amplitude and phase based on the pilot signal serving as the amplitude and phase reference
Although a phase output is obtained, this is again a demodulated output that is synchronously detected for each subcarrier.

Thus, ((r_i1, R_i2, ...,
r_iN) × S_i ^-1), Each transmission OF
The ith subcarrier of the DM signal (t_i1, T_i2,
..., t_iN) Can be obtained. This operation
For all subcarriers,
Information signal (t_i1, T_i2, ..., t_iNCan demodulate)
it can. In this way, the sub-carriers are
By measuring the amplitude and phase of each rear,
(R_i1, R_i2, ..., r_iN) To the transmission signal (t_i1,
t_i2, ..., t_iNTransfer function S for restoring_iGot
And its inverse matrix S_i ^-1Is calculated, and ((r_i1, R_i2, ...,
r_iN) × S_i ^-1) To calculate the transmission signal
(T _i1, T_i2, ..., t_iN) And get demodulated output
be able to.

As described above, according to the present invention, a transfer coefficient S ⁱ for interference cancellation is obtained for each subcarrier,
_{((R i1, r i2,} ···, r iN) × S i -1) only operation,
The interference between the channels is canceled and the transmission signals (t _i1 , t
_i2 ,..., t _iN ), and demodulation becomes possible. Further, as described herein, the present invention does not need to perform complicated signal processing in the equalizer and does not perform feedback control, so-called feed-forward control. Stable operation can be expected.

(Second Embodiment) Next, another embodiment of the present invention will be described with reference to FIG. OFDM is commonly used in combination with error correction and interleaving to improve the performance against fading. An embodiment combining error correction and interleaving is shown in FIG.

In FIG. 3, the transmission information signal (t _i1 ,
t _i2 ,..., t _iN ) are the error correction encoders 15-1 to 15-15.
After error correction coding is performed in -N, interleavers 16-1 to 16-N perform interleaving in the subcarrier direction, that is, in the frequency axis direction. This is performed in order to avoid a continuous error against a level drop (notch) near a certain frequency and to obtain a high error correction coding gain.

On the receiving side, the demodulated output is subjected to deinterleaving, which is the reverse operation of the interleaving on the transmitting side, in the deinterleavers 17-1 to 17-N.
The data is decoded by the error correction decoders 18-1 to 18-N. This embodiment is a modification of the first embodiment, and includes the same components as those of the first embodiment. The components other than those described above are the same as those in the first embodiment, and a description thereof will not be repeated.

(Third Embodiment) In the configuration of FIG. 3, in the case of fading with a relatively long delay, good characteristics can be obtained because no continuous error occurs, but in the case of fading with a short delay, FIG. As described above, since the fading period on the frequency axis is long, the notch is widened, a continuous error is likely to occur in this portion, and the error correction gain is reduced.

The invention according to claim 8 will be described with reference to FIG. The present invention is an invention for improving the reduction of the error correction gain as described above. Transmission information signal (t
_i1 , t _i2 ,..., t _iN ) are subjected to error correction coding in error correction encoders 15-1 to 15-N shown in FIG. ) And the transmission antenna direction (spatial direction), and performs interleaving in combination.

On the receiving side, the demodulated output is subjected to deinterleaving, which is the reverse operation of the interleaving on the transmitting side, in the deinterleaver 17, and thereafter the error correction decoder 18-
1 to 18-N. By doing so, interleaving is performed by combining the antenna direction and the frequency axis direction, so that an antenna (space) diversity effect can be obtained in addition to the frequency diversity effect. For this reason, even in fading with a short delay, the occurrence of continuous errors is reduced, a decrease in error correction coding gain can be reduced, and high quality can be achieved.

The output of one error correction encoder is interleaved in the interleaver 16 by combining it in the subcarrier direction and the transmission antenna direction. The same effect can be obtained when decoding is performed by a device. (Fourth Embodiment) Next, one embodiment of the invention according to claims 5 and 11 will be described with reference to FIG. As shown in FIG. 6, in the present invention, the number of transmitting antennas is two and the number of receiving antennas is also two.

On the transmitting side, the polarization of the transmitting antenna 5-1A and the transmitting antenna 5-2A are set to different polarizations, for example, vertical polarization and horizontal polarization, and on the receiving side, the receiving antenna 8-1A and the receiving antenna 8-1A are connected. Similarly, the antenna 8-2A has different polarizations, for example, vertical polarization and horizontal polarization, respectively. Thereby, for example, the path between the transmission antenna 5-1A and the reception antenna 8-1A and the path between the transmission antenna 5-2A and the reception antenna 8-2A are separated based on the degree of polarization discrimination of the transmission and reception antennas. be able to. Here, the transfer function S _i of the i-th subcarrier is given by the following equation as a determinant of (2 × 2) elements.

(Equation 6) In this determinant, the fact that the absolute values of S ₁₁ and S ₂₂ can be sufficiently larger than the absolute values of S ₁₂ and S ₂₁ means that the transmission and reception antennas can be separated by the polarization discrimination. Therefore, when calculating the inverse matrix S _i ^-1 for S _i,
Since the denominator of the determinant can be prevented from being 0 in the inverse matrix operation, the OFF received for each antenna
The operation of (r ₁ , r ₂ ) × S _i ^-1 is unlikely to diverge for (r ₁ , r ₂ ), which is the i-th subcarrier pair of the DM signals R ₁ and R ₂ .

Therefore, the degree of separation of the transmission signals (t ₁ , t ₂ ) on the receiving side can be increased, and stable communication can be performed. In addition, when the present apparatus is considered to be deployed in a cellular configuration, interference with cells having different polarizations can be reduced by the polarization discrimination degree. Therefore, even if the transmission capacity is increased by doubling the power, the interference power can be reduced by the polarization discrimination degree for different polarizations, so that the interference power does not increase for each polarization. For this reason, even in the deployment using the cellular configuration, the interference power does not increase. Therefore, according to the present invention, the area capacity of the system can be approximately doubled as compared with the case where the same polarization is used.

(Fifth Embodiment) Next, another embodiment of the invention according to claims 5 and 11 will be described with reference to FIG. As shown in FIG. 7, in the present invention, the number of transmitting antennas is two, and the number of receiving antennas is also two.

On the transmitting side, the transmitting antenna 5-1A and the transmitting antenna 5-2A have different polarizations, for example, a vertical polarization and a horizontal polarization. Similarly, the antenna 8-2A has different polarizations, for example, vertical polarization and horizontal polarization, respectively. Thereby, for example, the path between the transmission antenna 5-1A and the reception antenna 8-1A and the path between the transmission antenna 5-2A and the reception antenna 8-2A are separated based on the degree of polarization discrimination of the transmission and reception antennas. be able to.

According to the present invention, the degree of separation of the transmission signals (t ₁ , t ₂ ) on the receiving side can be increased, and the polarization is different. Even in the case of fading, in addition to the frequency diversity effect peculiar to OFDM, the correlation coefficient of diversity due to antenna (space) and polarization can be reduced. Therefore, a large diversity effect is obtained, the occurrence of continuous errors is reduced, the decrease in error correction coding gain can be reduced, and high quality can be achieved.

(Sixth Embodiment) Next, an embodiment of the present invention will be described with reference to FIG.
In this embodiment, the number of transmitting antennas is 2 and the number of receiving antennas is 2, as in the embodiment of FIG. For example, vertical polarization and horizontal polarization are used, and on the receiving side, the reception antenna 8-1A and reception antenna 8-2A are similarly set to different polarizations, for example, vertical polarization and horizontal polarization, respectively.

According to this, since different polarizations are used, an effect of polarization diversity can be expected, and communication quality can be improved. In the present invention, the transmission information signal is distributed and the same transmission information signal is transmitted to the OFDM modulators 1-1, 1
Switching is performed between the case of inputting the transmission information signals T ₁ and −2 and the case of inputting the transmission information signals T ₁ and T ₂ that have been subjected to serial / parallel conversion.
Here, when the transmission information signal subjected to the serial-to-parallel conversion is transmitted, the information transmission speed is 2 compared to the case where the same transmission information signal is transmitted.
Double.

On the other hand, when transmitting the same transmission information signal, the receiving side adds the two subcarrier demodulated outputs or outputs the higher of the received level among the two subcarrier demodulated outputs. The effect can be obtained and high quality can be achieved. In the present invention,
The communication quality measuring means 22 for measuring the reception quality measures the reception quality, and the first switching unit 20 converts the same transmission information signal if the reception quality is low with respect to the threshold for the switching determination, and performs serial-parallel conversion if the reception quality is high. The transmitted transmission information signals T ₁ and T ₂ are sent to the OFDM modulators 1-1 and 1-2.

On the other hand, on the receiving side, the second switch 21 adds two subcarrier demodulation outputs if the reception quality is low with respect to the threshold value for switching determination, or, among the two subcarrier demodulation outputs, The higher reception level is output. If it is higher than the threshold, the demodulated output is output as it is. The switching control of the first switch 20 and the second switch 21 is performed based on the measurement result of the communication quality measuring unit 22.

As a result, although the transmission rate is reduced to １ ／, if the same transmission information signal is transmitted by the two OFDM modulators, the polarization diversity effect can be obtained, so that high quality can be achieved. On the other hand, when the propagation environment is good, as in the embodiment of FIG. 6, since the OFDM signals with different polarizations can be separated, different transmission information can be transmitted and twice the transmission capacity is required. It can be transmitted without increasing the frequency. Thus, the quality and the transmission capacity can be adaptively controlled according to the propagation environment and the reception quality.

In the above embodiment, in the transmitting apparatus, the transmission OFDM symbol timing of each OFDM modulator and the local oscillator of the frequency converter are common, and a pilot is transmitted to estimate a transmission coefficient between the transmitting and receiving antennas. . Further, in the receiving apparatus, the local oscillator of the frequency converter is shared, and the N × N combination of the transmitting and receiving antennas is used for the output of the fast Fourier transformer using the pilot signal for each subcarrier. The transmission coefficient is measured by detecting the reception amplitude and phase of the pilot signal.

Based on this, N × N for each subcarrier
Inverse matrix S to the matrix Si of_i ^-1Calculate the fast Fourier
For the output of the hand transducer, the received signal
(R ₁, R_Two, ..., r_N) To ((r₁, R_Two, ...,
r_N) × S_i ^-1), The transmission OFDM
The ith subcarrier of the signal (t₁, T_Two, ...,
t_N) Can be estimated. Accordingly
MIM by the OFDM method without using an equalizer
An O-channel signal transmission device is realized.

(Seventh Embodiment) Next, another embodiment of the present invention will be described with reference to FIG. This form corresponds to claims 1, claim 20 to claim 22, and claim 26. FIG. 9 is a block diagram showing a configuration of the OFDM signal transmission system of this embodiment. In this embodiment, the transmitting antenna, the OFDM signal transmitting device, the receiving antenna, the OFDM signal receiving device, the inverse matrix calculating means, and the interference canceling means of the first aspect are each composed of an antenna 3
7, OFDM signal transmitting apparatus 30, antenna 51, OFD
It corresponds to the M signal receiving device 50, the inverse matrix calculator 57, and the pre-interference canceller 32.

In the OFDM signal transmitting apparatus according to the twentieth aspect, the pilot signal generating means, data converting means, inverse matrix receiving means, pre-interference canceling means, multiplexing means,
The fast inverse Fourier transform means, the symbol timing generating means, the transmitting frequency converting means and the transmitting local oscillating means comprise a pilot signal generator 34, a data converter 31,
Receiver 41, pre-interference canceller 32, multiplexing circuit 3
3, corresponding to the fast inverse Fourier transformer 35, the timing signal generator 38, the frequency converter 36 and the local oscillator 39,
The frequency conversion means for reception, the local oscillation means for reception, the fast Fourier transform means, the demodulation means, the timing signal generation means, the inverse matrix calculation means and the inverse matrix information transmission means of the OFDM signal receiving apparatus are a frequency converter 52 and a local oscillator 55, respectively. ,
It corresponds to the fast Fourier transformer 53, the demodulator 54, the timing signal generator 56, the inverse matrix calculator 57, and the transmitter 58.

The information transmitting antenna and the information receiving antenna according to claim 26 correspond to the transmitting antenna 59 and the receiving antenna 40, respectively. The OFDM signal transmission system shown in FIG.
It comprises a DM signal receiving device 50. Note that this O
When the FDM signal transmission system is applied to mobile communication or the like, it is preferable that the OFDM signal transmission device 30 be mounted on the base station side and the OFDM signal reception device 50 be mounted on the mobile terminal on the user side.

As shown in FIG. 9, the OFDM signal transmitting apparatus 30 includes a data converter 31 and a pre-interference canceller 3.
2, multiplexing circuit 33, pilot signal generator 34, fast inverse Fourier transformer 35, frequency converter 36, antenna 3
7, a timing signal generator 38, a local oscillator 39, a receiving antenna 40, and a receiver 41 are provided. Also, a data converter 31, a multiplexing circuit 33, a pilot signal generator 34, a fast inverse Fourier transformer 35, a frequency converter 36
And N antennas 37 (a plurality).

On the other hand, the OFDM signal receiving apparatus 50 includes an antenna 51, a frequency converter 52, and a fast Fourier transformer 5
3, a demodulator 54, a local oscillator 55, a timing signal generator 56, an inverse matrix calculator 57, a transmitter 58, and a transmission antenna 59 are provided. The antenna 51, the frequency converter 52, the fast Fourier transformer 53, and the demodulator 54
Each has N (plural).

The number N of components in the OFDM signal transmitting device 30 and the number N of components in the OFDM signal receiving device 50 are the same. That is, the number of antennas N on the transmitting side and the number N of antennas on the receiving side are required to obtain the inverse matrix described later.
Must be the same as

[0090] Data converters 31 (1) ~31 (N) converts the transmission data T ₁ through T _N are inputted respectively to the OFDM symbol. Each data converter 31 includes a modulator (for example, a modulator such as BPSK, QPSK, or ASK) for modulating a data sequence input as a serial signal into a symbol, and a serial-parallel converter for converting a symbol into a parallel signal. Built-in. That is, the symbol corresponding to the input transmission data is converted into a parallel signal format by the data converter 3.
1 is output.

The receiver 41 includes an OFDM signal receiving device 50
The information of the inverse matrix transmitted from the
And receive the inverse matrix. Pre-interference canceller 32
Is the interference cancellation using the inverse matrix acquired by the receiver 41.
Perform preprocessing for the cell. Specifically, the transmission data
T₁~ T_NData converters 31 (1) to 31 (N) output
OFDM symbols (M₁, M_Two, ..., M _NEach)
Various subcarrier components (m₁, M_Two, ..., m_NAll)
Are multiplied by the inverse matrix.

N pilot signal generators 34 (1) to 34 (3)
4 (N) outputs different known pilot signals. Each of multiplexing circuits 33 (1) to 33 (N) converts an OFDM symbol output from pre-interference canceller 32 and a pilot signal output from pilot signal generators 34 (1) to 34 (N). The multiplexed signal is output on the time axis.

Each of the fast inverse Fourier transformers 35 (1) to 35 (N) performs fast inverse Fourier transform (IFFT) processing on the signals output from the multiplexing circuits 33 (1) to 33 (N). Apply. A common symbol timing signal is supplied from the timing signal generator 38 to the N fast inverse Fourier transformers 35 (1) to 35 (N). Fast inverse Fourier transformer 35
The OFDM signals output from each of (1) to 35 (N) are frequency-converted to radio frequencies by frequency converters 36 (1) to 36 (N). The local oscillator 39 supplies a common local oscillation signal to the N frequency converters 36 (1) to 36 (N).

Therefore, from the N antennas 37 (1) to 37 (N) connected to the outputs of the frequency converters 36 (1) to 36 (N), OFDM signals of the same radio frequency are simultaneously transmitted as radio waves. Sent. N OFDM signals transmitted from the antennas 37 (1) to 37 (N) are added in space, and
N arranged at different positions on the signal receiving device 50 side
Antennas 51 (1) to 51 (N).

The O received by the antennas 51 (1) to 51 (N)
The FDM signals are respectively converted into frequency converters 52 (1) to 52 (N).
Low frequency OFDM suitable for signal processing through
The frequency is converted to a signal. Frequency converters 52 (1) to 52
(N) is supplied with a common local oscillation signal from the local oscillator 55. OFDM signals output from the frequency converters 52 (1) to 52 (N) are fast Fourier transformers 53, respectively.
Input to (1) -53 (N) and fast Fourier transform (FFT)
Processed. Fast Fourier Transformers 53 (1) to 53 (N)
Are output to demodulators 54 (1) to 54 (N) and demodulated into bit strings.

Note that the OFDM signal receiving apparatus 5 shown in FIG.
0 does not include an element corresponding to the interference canceller. In this OFDM signal transmission system, OFD
The interference is canceled by the function of the pre-interference canceller 32 on the M signal transmitting apparatus 30 side. Since there is no need to provide an interference canceller in the OFDM signal receiving apparatus 50,
The configuration of the DM signal receiving device 50 is simplified, and power consumption is suppressed.

The inverse matrix calculator 57 extracts the received pilot signal from the output of each of the fast Fourier transformers 53 (1) to 53 (N). And, for each component of the subcarrier, it corresponds to each combination of N transmitting antennas 37 (1) to 37 (N) and N receiving antennas 51 (1) to 51 (N). The reception amplitude and phase of (N × N) pilot signals are detected. That is, since the pilot signal is known, it is possible to detect the transfer coefficient representing the transfer function between the transmitting antenna and the receiving antenna by normalizing the received pilot signal using the known signal. it can.

The inverse matrix calculator 57 uses the detected transfer coefficient as a component to form a matrix A _i composed of (N × N) elements.
^Is calculated by calculating the inverse matrix A _i ^-1 of The transmitter 58 transmits the information of the inverse matrix A _i ^-1 obtained by the inverse matrix calculator 57 to the OFDM signal transmission device 30 via the transmission antenna 59. In this embodiment, the information of the inverse matrix A _i ^-1 obtained by the inverse matrix calculator 57 of the OFDM signal receiving device 50 is
Although a transmitter 58, a transmitting antenna 59, a receiving antenna 40, and a receiver 41 are specially provided for transmitting the signal to the M signal transmitting device 30, they may be replaced with components provided in advance.

For example, the antenna 51 can be used instead of the transmitting antenna 59, and the antenna 37 can be used instead of the receiving antenna 40. Next, the operation of each unit of the OFDM signal transmitting device 30 and the OFDM signal receiving device 50 will be described in further detail. In the OFDM signal transmitting apparatus 30, each of the pilot signal generators 34 (1) to 34 (1) to 34
Known pilot signals output from (N) are multiplexed into transmission signals by multiplexing circuits 33 (1) to 33 (N), respectively.
The signals are transmitted from the antennas 37 (1) to 37 (N).

Here, a pilot signal transmitted from each antenna 37 (j) is represented by P _j . Each pilot signal _Pj is _supplied to the multiplexing circuit 3 in the same manner as the transmission data signal.
3. Since the signal passes through the high-speed inverse Fourier transformer 35 and the frequency converter 36, it is OFDM-modulated in the same manner as the transmission data. Further, common symbol timing is supplied from the timing signal generator 38 to the fast inverse Fourier transformers 35 (1) to 35 (N), respectively, and the local oscillator 39 is supplied to the frequency converters 36 (1) to 36 (N). Supplies a common local oscillation frequency.

For this reason, the OFDM symbol timing of each subcarrier of each OFDM signal transmitted from the antennas 37 (1) to 37 (N) is common to all systems. Also, the carrier signal of the OFDM signal becomes coherent. Therefore, the OFDM signal receiving apparatus 50 does not need to perform automatic frequency control and OFDM symbol timing reproduction individually for each OFDM signal. For this reason, the signal processing amount in the OFDM signal receiving device 50 is relatively small.

An OFDM signal containing P _j as a pilot signal transmitted from each antenna 37 (j) is an OFD signal.
The signals are received by antennas 51 (1) to 51 (N) in M signal receiving apparatus 50, respectively. Here, the signal is transmitted from the j-th antenna 37 (j) on the transmitting side and the k-th antenna 51 on the receiving side.
The received pilot signal received at (k) is represented by P _{j, k} ,
Antenna 37 (j) on the transmitting side and antenna 51 (k) on the receiving side
Is represented by H _{j, k} , the following relationship is established.

(Equation 7) In the OFDM signal receiving apparatus 50, P _{j, k} of the received pilot signal is frequency-converted by the frequency converter 52, and then Fourier-transformed by the fast Fourier transformer 53. As a result, the received pilot signal P _{j, k} is separated for each subcarrier component. The inverse matrix calculator 57 receives the pilot signal P _{j, k} separated for each subcarrier component.
Is input from the output of the fast Fourier transformer 53, and the inverse matrix is calculated.

In order for the OFDM signal receiving apparatus 50 to extract the received pilot signal from the received signal, it is necessary to identify the pilot signal. If a preamble for identifying this is added to, it can be easily identified. Further, for example, in the OFDM signal transmitting apparatus 30, each pilot signal P ₁ ,
P _2, · · ·, by transmitting mutually offset timings as P _N do not overlap on the time axis, each pilot signal in the OFDM signal receiving apparatus _{50 P 1, P 2, ···} , a P _N mutually Can be separated.

The inverse matrix calculator 57 is configured to transmit the antenna 3 on the transmitting side.
7 (1) to 37 (N) and the reception amplitude of the input reception pilot signal for each of the (N × N) sets corresponding to the respective combinations of the reception side antennas 51 (1) to 51 (N). And a phase (amplitude and phase of a reference carrier used for synchronous detection) are detected for each subcarrier. Therefore, for each subcarrier component, the transmitting-side antennas 37 (1) to 37 (N)
Of transfer coefficients A _i having (N × N) elements corresponding to each combination of the antennas 51 (1) to 51 (N) on the receiving side (the subscript i represents the component of each subcarrier) Is obtained.

Further, an inverse matrix calculator 57 calculates an inverse matrix A _i ^-1 of the transfer coefficient matrix A _i for each subcarrier component, and outputs information of the inverse matrix A _i ^-1 to the transmitter 58. I do.
Here, the received pilot signal P _{j, k} and the pilot signal P
_j, and the i-th subcarrier component of the transmission response H _{j, k} are represented by p _{i: j, k} , pilot signal p _{i: j,} and transmission response h _{i: j, k} , respectively. The following expression is established similarly to the expression).

(Equation 8) Therefore, each component of the matrix A _i is the transfer response hi _{: j, k} itself, and the matrix A _i is represented by the following equation.

(Equation 9) The information of the inverse matrix A _i ^-1 obtained by the inverse matrix calculator 57 is modulated inside the transmitter 58 and transmitted as a radio wave via the transmission antenna 59. The information of the inverse matrix A _i ^-1 is represented by OFD
The signal is received by the receiving antenna 40 of the M signal transmitting device 30,
The signal is demodulated inside the receiver 41. The information of the inverse matrix A _i ^-1 acquired by the receiver 41 is input to the pre-interference canceller 32.

The pre-interference canceller 32 calculates the inverse matrix A _i ^-1
The data signal to be transmitted (T ₁ , T ₂ ,.
, T _N ), the i-th subcarrier component of the output signal (M ₁ , M ₂ ,..., M _N ) of the data converters 31 (1) to 31 (N) corresponds to (m _i1 , m _i2 performed, ···, m _iN) for _{((m i1, m i2,} ···, m iN) relative × a every subcarrier components calculation of _i ^-1).

The j-th (j = 1 to N) -th components of the operation result of the pre-interference canceller 32 are input to the multiplexing circuits 33 (j) corresponding to the j-th antenna 37 (j). You. The data signals multiplexed by each of the multiplexing circuits 33 (1) to 33 (N) are respectively converted by the fast inverse Fourier transformer 35.
The inverse Fourier transform is performed in (1) to 35 (N), and the frequency converter 36
(1) to (N) are frequency-converted into radio frequency signals, and the OFDM signal receiving device 5 is transmitted from each of the antennas 37 (1) to 37 (N).
Sent toward zero.

The ith subcarrier component (t _{i: 1} , t _i ) of the data signal transmitted from each of the antennas 37 (1) to 37 (N)
_{i: 2} ,..., t _{i: N} ) is represented by the following equation.

(Equation 10) The transmitted data signal is received by each of the antennas 51 (1) to 51 (N) of the OFDM signal receiving device 50, and the received signal is affected by the transmission response hi _{: j, k} . That, i th subcarrier component of the data signal received _{(r i: 1, r i} : 2, ···, r i: N) expressed by the following equation is established.

[Equation 11] The following equation is obtained based on the above equations (10) and (11).

(Equation 12) That is, OFDM signal symbols (m _i1 , m _i2 ,..., _{M iN} ) transmitted by the OFDM signal
The M signal receiving device 50 receives the received signals (ri _{: 1} , ri _{: 2} ,...).
, R _{i: N} ).

Also, the fast Fourier transformers 53 (1) to 53 (53)
(N), ie, the symbol (m
_i1 , _mi2 ,..., _miN ) are demodulated by demodulators 54 (1) to 54 (N) and converted into bit strings, whereby the original data signal (T ₁ , T ₂ , ...
., T _N ). It works as above,
Although N OFDM signals are simultaneously transmitted using the same frequency band on the same propagation path, the OFDM signal receiving apparatus 50 according to the embodiment shown in FIG. In the same manner as described above, each data signal can be separated and received.

In this embodiment, since the pre-interference canceller 32 for canceling interference is provided on the OFDM signal transmitting apparatus 30 side, signal processing on the OFDM signal receiving apparatus 50 side is simplified. That is, simplification of the configuration of the OFDM signal receiving device 50 and reduction of power consumption are realized. For example, assuming that the OFDM signal receiving device 50 is mounted on a mobile terminal, the mobile terminal can be reduced in size and economical. Become.

(Eighth Embodiment) Next, another embodiment of the present invention will be described with reference to FIG. This form is defined in claims 1, 23 to 25.
And claim 26. FIG. 10 shows this type of OFD.
FIG. 2 is a block diagram illustrating a configuration of an M signal transmission system. This embodiment is a modification of the seventh embodiment. In FIG. 10, elements corresponding to those in FIG. 9 are denoted by the same reference numerals.

In this embodiment, the transmitting antenna of claim 1
The OFDM signal transmitting device, the receiving antenna, the OFDM signal receiving device, the inverse matrix calculating means, and the interference canceling means include an antenna 37, an OFDM signal transmitting device 30, an antenna 51, an OFDM signal receiving device 50, and an inverse matrix calculating device 4, respectively.
2 and the pre-interference canceller 32. And a pilot signal generating means, a data converting means, an information receiving means, an inverse matrix calculating means, a multiplexing means, a high-speed inverse Fourier transform means, a symbol timing generating means, a transmitting frequency converting means, and an OFDM signal transmitting apparatus. The local oscillation means for transmission includes a pilot signal generator 34, a data converter 31, a receiver 41, an inverse matrix calculator 42, a multiplexing circuit 33, a fast inverse Fourier transformer 35, a timing signal generator 38, and a frequency converter 36. And a local oscillator 39. The receiving frequency converting means, the receiving local oscillating means, the fast Fourier transforming means, the demodulating means, the timing signal generating means and the information transmitting means of the OFDM signal receiving apparatus are respectively provided with a frequency converter 52, a local Oscillator 55, fast Fourier transformer 53, demodulator 54, timing signal generator 56
And the transmitter 60.

The information transmitting antenna and the information receiving antenna of claim 26 correspond to the transmitting antenna 59 and the receiving antenna 40, respectively. OFDM shown in FIG.
The signal transmission system has the same OFDM system as the system shown in FIG.
It comprises a signal transmitting device 30 and an OFDM signal receiving device 50. When the OFDM signal transmission system is applied to mobile communication or the like, the OFDM signal transmission device 30 is mounted on the base station side, and the OFDM signal reception device 50 is installed.
Is desirably mounted on the mobile terminal on the user side.

As shown in FIG. 10, an OFDM signal transmitting apparatus 30 includes a data converter 31 and a pre-interference canceller 3.
2, multiplexing circuit 33, pilot signal generator 34, fast inverse Fourier transformer 35, frequency converter 36, antenna 3
7, a timing signal generator 38, a local oscillator 39, a receiving antenna 40, a receiver 41, and an inverse matrix calculator 42.

The data converter 31, the multiplexing circuit 3
3, N (plural) pilot signal generators 34, fast inverse Fourier transformers 35, frequency converters 36, and antennas 37 are provided. On the other hand, the OFDM signal receiving apparatus 50 includes an antenna 51, a frequency converter 52, a fast Fourier transformer 53, a demodulator 54, a local oscillator 55, a timing signal generator 56, a transmitter 60 and a transmitting antenna 5
9 is provided.

The antenna 51, the frequency converter 52,
The fast Fourier transformer 53 and the demodulator 54 each have N
Individual (plural). OFDM signal transmitter 30
And the number N of components in the OFDM signal receiving apparatus 50 are the same. That is, in order to obtain an inverse matrix described later, the number N of antennas on the transmitting side and the number N of antennas on the receiving side must be the same.

Data converters 31 (1) to 31 (N) convert input transmission data T _{1 to} T _N into OFDM symbols. Each data converter 31 includes a modulator (for example, a modulator such as BPSK, QPSK, or ASK) for modulating a data sequence input as a serial signal into a symbol, and a serial-parallel converter for converting a symbol into a parallel signal. Built-in. That is, the symbol corresponding to the input transmission data is converted into a parallel signal format by the data converter 3.
1 is output.

The receiver 41 includes an OFDM signal receiving device 50
Receiving information of the received pilot signal transmitted from the OFDM signal receiving apparatus 50 via the receiving antenna 40,
Demodulate the received signal. The inverse matrix calculator 42, based on the information of the received pilot signal received by the receiver 41,
Determined by calculating the inverse matrix A _i ^-1 of the detected transmission coefficient and the component (N × N) matrix composed of pieces of element A _i.

The pre-interference canceller 32 performs pre-processing for interference cancellation using the inverse matrix obtained by the inverse matrix calculator 42. Specifically, for each of the sub data of the OFDM symbols (M ₁ , M ₂ ,..., M _N ) output by the data converters 31 (1) to 31 (N) for the transmission data T _{1 to} T _N. All the carrier components (m ₁ , m ₂ ,..., _{M N} ) are multiplied by the inverse matrix.

N pilot signal generators 34 (1) to 34 (3)
4 (N) outputs different known pilot signals. Each of multiplexing circuits 33 (1) to 33 (N) converts an OFDM symbol output from pre-interference canceller 32 and a pilot signal output from pilot signal generators 34 (1) to 34 (N). The multiplexed signal is output on the time axis.

Each of the fast inverse Fourier transformers 35 (1) to 35 (N) performs fast inverse Fourier transform (IFFT) processing on the signals output from the multiplexing circuits 33 (1) to 33 (N). Apply. A common symbol timing signal is supplied from the timing signal generator 38 to the N fast inverse Fourier transformers 35 (1) to 35 (N).

The OFDM signal output from each of the fast inverse Fourier transformers 35 (1) to 35 (N) is
The frequency is converted to a radio frequency in (1) to 36 (N). The local oscillator 39 supplies a common local oscillation signal to the N frequency converters 36 (1) to 36 (N). Therefore, from the N antennas 37 (1) to 37 (N) connected to the outputs of the frequency converters 36 (1) to 36 (N), OFDs of the same radio frequency are output.
The M signals are transmitted simultaneously as radio waves.

N OFDM signals transmitted from antennas 37 (1) to 37 (N) are added in space, and N antennas 51 (N) arranged at different positions on the OFDM signal receiving apparatus 50 side. 1) to 51 (N). OFDM signals received by the antennas 51 (1) to 51 (N) are:
The signals are frequency-converted into relatively low-frequency OFDM signals suitable for signal processing through frequency converters 52 (1) to 52 (N). The local oscillator 55 supplies a common local oscillation signal to the frequency converters 52 (1) to 52 (N).

The OFDM signals output from the frequency converters 52 (1) to 52 (N) are converted into the fast Fourier transformers 53, respectively.
Input to (1) -53 (N) and fast Fourier transform (FFT)
Processed. Fast Fourier Transformers 53 (1) to 53 (N)
Are output to demodulators 54 (1) to 54 (N) and demodulated into bit strings.

In the OFDM signal transmission system of FIG. 10, interference is canceled by the function of the pre-interference canceller 32 on the OFDM signal transmission device 30 side. OFD
Since there is no need to provide an interference canceller in the M signal receiving device 50, the configuration of the OFDM signal receiving device 50 is simplified, and power consumption is suppressed.

The transmitter 60 includes a fast Fourier transformer 53
(1) A received pilot signal is extracted from each output of (N). Then, for each subcarrier component, N
Of (N × N) pilot signals corresponding to each combination of the transmitting antennas 37 (1) to 37 (N) and the N receiving antennas 51 (1) to 51 (N). Detect the reception amplitude and phase. That is, since the pilot signal is known, it is possible to detect the transfer coefficient representing the transfer function between the transmitting antenna and the receiving antenna by normalizing the received pilot signal using the known signal. it can.

Information of the received pilot signal detected from the output of the fast Fourier transformer 53 ((N
× N) amplitude and phase information) are modulated inside the transmitter 60 and transmitted as a radio wave via the transmitting antenna 59 as OFD.
The signal is transmitted to the M signal transmitting device 30. In this embodiment, a transmitter 58, a transmitting antenna 59, and a receiving antenna 40 transmit information of a received pilot signal detected by the OFDM signal receiving apparatus 50 to the OFDM signal transmitting apparatus 30.
And the receiver 41 are specially provided, but may be replaced by components provided in advance.

For example, the antenna 51 can be used instead of the transmitting antenna 59, and the antenna 37 can be used instead of the receiving antenna 40. In this embodiment, the function of the inverse matrix calculator 57 shown in FIG.
9 is shifted to the OFDM signal transmitting apparatus 30 side as FIG.
The configuration is very different. Hereinafter, the OFDM of FIG.
The operation of the main parts of the signal transmitting device 30 and the OFDM signal receiving device 50 will be described in more detail.

As in the OFDM signal transmission system of FIG. 9, the OFDM signal transmitting apparatus 30 of FIG. 10 transmits an OFDM-modulated data signal and a known pilot signal from each of the antennas 37 (1) to 37 (N). , OFDM signal receiving apparatus 50 receives data signals and pilot signals as OFDM signals at antennas 51 (1) to 51 (N).

Further, in the OFDM signal transmitting apparatus 30, the sub-carrier components (m ₁ , m ₂ ,...,
m _N ) with the inverse matrix A _i ^-1 to obtain each antenna 37 (1) to 37 (3).
From 7 (N), the data signal obtained by integrating the inverse matrix A _i ^-1 is transmitted. The signals received by the antennas 51 (1) to 51 (N) include:
Since the inverse matrix A _i ^-1 has already been integrated on the transmission side, OF
In the DM signal receiving device 50, the antennas 51 (1) to
The data signals (m ₁ , m ₂ ,...)
.., _{M N} ) can be directly separated and taken out.

In the OFDM signal receiving apparatus 50, it is necessary to separate the received pilot signals from each other and extract them.
, Each pilot signal (P ₁ , P ₂ ,..., P
_N ) can be easily separated by sending them at different timings so that they do not overlap each other on the time axis. As described above, in the OFDM signal transmission system of FIG.
From the FDM signal receiving apparatus 50 side to the OFDM signal transmitting apparatus 3
0, the information of the received pilot signal is transmitted, and OFD
The M signal transmitting apparatus 30 is characterized in that an inverse matrix is obtained based on information (reception amplitude and phase) of a received pilot signal.

As described above, in the OFDM signal transmission system of FIG. 10, it is not necessary to mount the inverse matrix calculation function and the interference cancellation function on the OFDM signal receiving apparatus 50 side. Therefore, signal processing on the OFDM signal receiving device 50 side is simplified. That is, the OFDM signal receiving device 5
Since the configuration of FIG. 0 can be simplified and the power consumption can be reduced, for example, assuming that the OFDM signal receiving device 50 is mounted on the mobile terminal, the mobile terminal can be reduced in size and economical.

(Ninth Embodiment) Next, another embodiment of the present invention will be described with reference to FIG. This form is defined in claims 1 and 27 to 2.
9 corresponds. FIG. 11 is a block diagram showing a configuration of the OFDM signal transmission system of this embodiment. This embodiment is a modification of the eighth embodiment. In FIG. 11, FIG.
Elements corresponding to 0 are denoted by the same reference numerals.

In this embodiment, the transmitting antenna of claim 1
The OFDM signal transmitting device, the receiving antenna, the OFDM signal receiving device, the inverse matrix calculating means, and the interference canceling means include an antenna 37, an OFDM signal transmitting device 30, an antenna 51, an OFDM signal receiving device 50, and an inverse matrix calculating device 4, respectively.
2 and the pre-interference canceller 32. The pilot signal generating means, the inverse fast Fourier transform means, the transmitting frequency converting means, the receiving frequency converting means, the fast Fourier transforming means of the OFDM signal receiving apparatus according to claim 27,
The demodulation means, local oscillation means, and transmission / reception switch means include a pilot signal generator 81, a fast inverse Fourier transformer 82, frequency converters 83, 52, a fast Fourier transformer 53, a demodulator 54, a local oscillator 55, and a switch. 86, the data conversion means of the OFDM signal transmitting apparatus, the frequency conversion means for reception, the fast Fourier transform means,
The timing signal generating means, the inverse matrix calculating means, the fast inverse Fourier transform means, the transmitting frequency converting means, the local oscillating means, and the transmission / reception switching switch means are each a data converter 3
1, frequency converter 71, fast Fourier transformer 72, timing signal generator 73, inverse matrix calculator 42, fast inverse Fourier transformer 35, frequency converter 36, and switch 7
Corresponding to 5.

The OFDM signal transmission system shown in FIG. 11 is similar to the system shown in FIG.
0 and an OFDM signal receiving device 50. When the OFDM signal transmission system is applied to mobile communication or the like, it is desirable to mount the OFDM signal transmission device 30 on the base station side and mount the OFDM signal reception device 50 on the mobile terminal on the user side. .

In the OFDM signal transmission system shown in FIG. 11, each of the OFDM signal transmitting apparatus 30 and the OFDM signal receiving apparatus 50 uses the same antenna for transmission and reception, and performs time division between the transmission mode and the reception mode. It is assumed that the system is based on a TDD (Time Division Duplex) that is switched according to. Further, OFD of FIG.
In the M signal transmission system, a function of generating a pilot signal is provided on the OFDM signal receiving device 50 side.

As shown in FIG. 11, an OFDM signal receiving apparatus 50 includes an antenna 51, a frequency converter 52, a fast Fourier transformer 53, a demodulator 54, a local oscillator 55, a timing signal generator 56, and a pilot signal generator 81. , A high-speed inverse Fourier transformer 82, a frequency converter 83, a symbol timing generator 84, a switching control unit 85, and a switching switch 86.

An antenna 51, a frequency converter 52,
Each of the fast Fourier transformer 53, the demodulator 54, the pilot signal generator 81, the fast inverse Fourier transformer 82, the frequency converter 83, and the changeover switch 86 is provided with N (a plurality). On the other hand, the OFDM signal transmitting apparatus 3 shown in FIG.
To 0, a data converter 31, a pre-interference canceller 32, a fast inverse Fourier transformer 35, a frequency converter 36, an antenna 37, a timing signal generator 38, a local oscillator 39, a frequency converter 71, a fast Fourier transformer 72, Timing signal generator 73, switch control unit 74, and switch 75
Is provided.

Each of the data converter 31, the fast inverse Fourier transformer 35, the frequency converter 36, the antenna 37, the frequency converter 71, the fast Fourier transformer 72, and the changeover switch 75 includes N (a plurality). I have. OFD
The number N of components in the M signal transmitting device 30 and the number N of components in the OFDM signal receiving device 50 are the same.
That is, in order to obtain an inverse matrix described later, the number N of antennas on the transmitting side and the number N of antennas on the receiving side need to be the same.

The frequency converter 52, the fast Fourier transformer 53, the demodulator 54, the local oscillator 55, and the timing signal generator 56 in the OFDM signal receiving apparatus 50 perform the same functions as the corresponding elements in FIG. Omitted.

N pilot signal generators 81 (1) to 81 (8)
1 (N) outputs known pilot signals different from each other. Fast inverse Fourier transformer 82 (1) to 82 (N)
Performs inverse Fourier transform processing on pilot signals output from pilot signal generators 81 (1) to 81 (N), respectively. The fast inverse Fourier transformers 82 (1) to 82 (N) are supplied with a signal of a common symbol timing from a symbol timing generator 84.

The frequency converters 83 (1) to 83 (N) frequency-convert the pilot signals output as the OFDM signals from the fast inverse Fourier transformers 82 (1) to 82 (N) into radio frequencies. The frequency converters 83 (1) to 83 (N) are supplied with a common local oscillation signal from the local oscillator 55. Therefore, the N pilot signals appearing at the outputs of the frequency converters 83 (1) to 83 (N) have the same radio frequency. Frequency converter 8
When the OFDM signal receiving apparatus 50 is in the transmission mode, the N pilot signals output from the 3 (1) to 83 (N) pass through the changeover switches 86 (1) to 86 (N) and the antenna 51 ( 1) to 51 (N).

The switching control section 85 identifies the communication state between the OFDM signal transmitting apparatus 30 and the OFDM signal receiving apparatus 50, and N switching switches according to whether the OFDM signal receiving apparatus 50 is in the transmission mode or the reception mode. The states of 86 (1) to 86 (N) are switched. The data converter 31, the pre-interference canceller 32, the fast inverse Fourier transformer 35, the frequency converter 36, the timing signal generator 38, and the local oscillator 39 in the OFDM signal transmitting apparatus 30 have the same functions as the corresponding elements in FIG. Therefore, the description thereof will be omitted.

Signals received by antennas 37 (1) to 37 (N) are output when OFDM signal transmitting apparatus 30 is in the receiving mode.
Frequency converter 7 via changeover switches 75 (1) to 75 (N)
1 (1) to 71 (N) are input.

The switching control section 74 identifies the communication state between the OFDM signal transmitting apparatus 30 and the OFDM signal receiving apparatus 50, and sets N switching switches according to whether the OFDM signal transmitting apparatus 30 is in the transmission mode or the reception mode. The state of 75 (1) to 75 (N) is switched. The frequency converters 71 (1) to 71 (N)
The signals (pilot signals) received by the antennas 37 (1) to 37 (N) are frequency-converted to relatively low frequencies suitable for signal processing. The frequency converters 71 (1) to 71 (N) are supplied with a common local oscillation signal from the local oscillator 39.

The fast Fourier transformers 72 (1) to 72 (N)
OFDM output from frequency converters 71 (1) to 71 (N)
A fast Fourier transform is performed on a pilot signal received as a signal. Therefore, the fast Fourier transformer 72 (1)-
The outputs of 72 (N) include antennas 37 (1) to 37 (37), respectively.
The pilot signal received in (N) appears separated for each subcarrier component.

The fast Fourier transformers 72 (1) to 72 (N) are supplied with a signal of a common symbol timing from a timing signal generator 73 to extract each received pilot signal. The inverse matrix calculator 42 is based on the signals output from the fast Fourier transformers 72 (1) to 72 (N),
The reception amplitude and phase of each received pilot signal are detected for each subcarrier component, and an inverse matrix is obtained based on the detection result.

Next, the OFDM signal transmitting apparatus 30 shown in FIG.
The operation of the main part of the OFDM signal receiving apparatus 50 will be described in detail. In the OFDM signal transmitting apparatus 30, the inverse matrix calculator 4
2 is the inverse matrix A _i ^-1 of the transfer coefficient matrix A _i of each subcarrier
Is calculated. Then, the pre-interference canceller 32 performs inverse processing on each subcarrier component (m ₁ , m ₂ ,..., _{M N} ) of the data signal output from the data converters 31 (1) to 31 (N). The inverse matrix A _i ^-1 input from the matrix calculator 42 is multiplied.

The signal output from the pre-interference canceller 32 is subjected to inverse Fourier transform processing by the high-speed inverse Fourier transformers 35 (1) to 35 (N), and is output as an OFDM signal. These OFDM signals are supplied to the frequency converters 36 (1) to 36 (1).
The frequency is converted to a radio frequency at 36 (N), and transmitted from the antennas 37 (1) to 37 (N) via the changeover switches 75 (1) to 75 (N).

Signals transmitted from antennas 37 (1) to 37 (N) are added in space and added to antennas 51 (1) to 51 (N).
51 (N). However, the data signal (m ₁ , m ₂ ,..., _{M N} ) is transmitted after being multiplied by the inverse matrix A _i ^-1 in the pre-interference canceller 32 in advance.
As in the case of the systems of FIGS.
In (1) to 51 (N), the data signals (m ₁ , m ₂ ,..., M
_N ) are received separately.

Therefore, it is not necessary to provide a function for canceling interference on the OFDM signal receiving apparatus 50 side. That is, the method of acquiring pilot signal information in OFDM signal transmitting apparatus 30 is different from the system of FIG. In the OFDM signal receiving apparatus 50, the pilot signals (P ₁ , P ₂ ,...,
_PN ) is transmitted from each of the antennas 51 (1) to 51 (N). These pilot signals (P ₁ , P ₂ ,..., P _N )
In the OFDM signal transmitting apparatus 30, antennas 37 (1) to
The signal is received at 37 (N), OFDM demodulated, separated into components of each subcarrier, and input to the inverse matrix calculator 42.

The inverse matrix calculator 42 calculates an antenna 51 (1) for each subcarrier component from the received pilot signal.
To 51 (N) and calculates and stores the inverse matrix A _i ^-1 of the matrix A _i of the a component transfer coefficient for each combination of antennas 37 (1) ~37 (N) . The pre-interference canceller 32 converts the data signals output from the data converters 31 (1) to 31 (N) into an inverse matrix A.
Multiply _i ^-1 . The result is the fast inverse Fourier transformer 35
It is transmitted from antennas 37 (1) to 37 (N) via (1) to 35 (N) and frequency converters 36 (1) to 36 (N).

In the OFDM signal receiving apparatus 50, each of the antennas 51 (1) to 51 (N) adds the antenna 3 to the data signal.
7 (1) to 37 (N) receive a transmission response matrix when a signal is transmitted from the antenna 51 (1) to 51 (N) to the antenna 51 (1) to 51 (N), but use a common local oscillator for transmission and reception. since it is, and transmission coefficient of the transmission response matrix is the same as the aforementioned matrix a _i.

Therefore, each of the data signals (m _i1 , m _i2 ,..., M _iN ) is separately received by each of the antennas 51 (1) to 51 (N) of the OFDM signal receiving apparatus 50.
Therefore, the data signals (M _i1 , M _i2 ,..., M _iN ) appearing at the outputs of the fast Fourier transformers 53 (1) to 53 (N) are demodulated by the demodulators 54 (1) to 54 (N). By doing, OFDM
The data signals (T ₁ , T ₂ ,.
.., T _N ) are obtained.

In this embodiment, the OFDM signal receiving device 50
Side, a pilot signal generator 81 is provided.
There is no need to provide a pilot signal generation function on the DM signal transmitting device 30 side, and it is not necessary to provide the OFDM signal transmitting device 30 with the multiplexing circuit 33 of FIG. In addition, since the antennas 37 (1) to 37 (N) and the antennas 51 (1) to 51 (N) are shared for transmission and reception, the receiving antenna 4 shown in FIG.
0 and the transmission antenna 59 become unnecessary.

In the OFDM signal transmission system shown in FIG. 11, the function of calculating an inverse matrix and the function of canceling interference are
There is no need to mount it on the FDM signal receiving device 50 side. Therefore, signal processing on the OFDM signal receiving device 50 side is simplified. That is, simplification of the configuration of the OFDM signal receiving device 50 and reduction of power consumption are realized. For example, assuming that the OFDM signal receiving device 50 is mounted on a mobile terminal, the mobile terminal can be reduced in size and economical. Become.

The present invention is widely applied not only to a broadband mobile communication system but also to a radio system in which a large number of user radio stations are connected to a base station by using the OFDM scheme, such as a point-to-multipoint fixed radio access system. Applicable.

[0158]

According to the present invention, the transfer coefficient (amplitude / phase) of each carrier is measured directly using the pilot signal in the OFDM signal, instead of estimating the transfer function on the time axis by the equalizer. To obtain a transfer coefficient for canceling interference between OFDM signals for each subcarrier,
Easy and highly accurate interference cancellation between channels is possible, and feed-forward processing can be performed without performing feedback control such as an equalizer, resulting in stable operation even in severe frequency-selective fading environments. Can be expected.

According to the invention of claim 8, in the transmitting and receiving apparatus according to claim 2, interleaving is performed in two dimensions of a subcarrier direction (frequency axis direction) and a transmission antenna direction (spatial direction). Therefore, even in fading with a short delay, occurrence of continuous errors is reduced, a decrease in error correction coding gain can be reduced, and high quality can be achieved.

Further, according to the fifth, eleventh, and seventeenth aspects of the invention, in the transmitting / receiving apparatus of the second, eighth, and fourteenth aspects, the number of transmitting antennas is two and the number of receiving antennas is two. By using orthogonal polarization (for example, horizontal polarization and vertical polarization, or right-handed polarization and left-handed polarization), polarization discrimination of the transmitting and receiving antennas can be increased.
Since the degree of separation between two channels can be increased, high quality can be achieved.

In the fourteenth aspect,
The same transmission information signal is divided into two OFs by distributing the transmission information signal.
Switching between the case of inputting to the DM modulator and the case of inputting two transmission information signals subjected to serial / parallel conversion, and changing and controlling these in accordance with the threshold value for switching determination, enables quality and transmission capacity to be reduced. Adaptive control can be performed according to the propagation environment and reception quality.

Further, according to the twentieth aspect of the present invention, the operation amount,
That is, the function of the interference canceller having a large circuit scale is
Since it can be arranged on the DM signal transmitting device side, there is an advantage that the circuit scale of the OFDM signal receiving device can be reduced. By applying the present invention, the mobile terminal can be reduced in size and economy. In addition, according to the invention of claim 23, not only the function of the inverse matrix calculator but also the function of the inverse matrix calculator can be provided on the OFDM signal transmitting apparatus side, so that the circuit scale of the OFDM signal receiving apparatus can be further reduced.

In the invention of claim 27, since the same antenna is used for both transmission and reception, it is not necessary to add a special antenna for transmitting pilot signal information and inverse matrix information. Further, claim 20 and claim 2
As in the third aspect, the circuit scale of the OFDM signal receiving apparatus can be further reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a first embodiment.

FIG. 2 is a time chart showing an example of a transmission OFDM signal including a pilot signal.

FIG. 3 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a second embodiment.

FIG. 4 is a graph showing an example of fading characteristics.

FIG. 5 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a third embodiment.

FIG. 6 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a fourth embodiment.

FIG. 7 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a fifth embodiment.

FIG. 8 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a sixth embodiment.

FIG. 9 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a seventh embodiment.

FIG. 10 is a block diagram illustrating a configuration of an OFDM signal transmission system according to an eighth embodiment.

FIG. 11 is a block diagram illustrating a configuration of an OFDM signal transmission system according to a ninth embodiment.

FIG. 12 is a block diagram illustrating a configuration example of a conventional transmission / reception device on a MIMO channel.

[Explanation of symbols]

 1-1 to 1-N OFDM modulator 2 OFDM symbol timing control circuit 3-1 to 3-N frequency converter 4 local oscillator 5-1 to 5-N transmission antenna 5-1A vertically polarized transmission antenna 5-2A Horizontally polarized transmitting antenna 6-1 to 6-N Pilot signal generating means 7-1 to 7-N Multiplexing means 8-1 to 8-N Receiving antenna 8-1A Vertically polarized receiving antenna 8-2A Horizontally polarized Wave receiving antenna 9-1 to 9-N Frequency converter 10 Local oscillator 11-1 to 11-N Fast Fourier transformer 12 OFDM symbol timing recovery means 13 Inverse matrix calculation means 14 Subcarrier demodulation means 15-1 to 15- N error correction encoder 16, 16-1 to 16-N interleaver 17, 17-1 to 17-N deinterleaver 18-1 to 18-N error correction decoder 20 first Switch 21 second switch 22 communication quality measuring means 30 OFDM signal transmitter 31 data converter 32 pre-interference canceller 33 multiplexing circuit 34 pilot signal generator 35 high-speed inverse Fourier transformer 36 frequency converter 37 antenna 38 timing Signal Generator 39 Local Oscillator 40 Receiving Antenna 41 Receiver 42 Inverse Matrix Calculator 50 OFDM Signal Receiving Device 51 Antenna 52 Frequency Transformer 53 Fast Fourier Transformer 54 Demodulator 55 Local Oscillator 56 Timing Signal Generator 57 Inverse Matrix Calculator 58 Transmitter 59 Transmit antenna 60 Transmitter 71 Frequency converter 72 Fast Fourier transformer 73 Timing signal generator 74 Switching controller 75 Switching switch 81 Pilot signal generator 82 Fast inverse Fourier transformer 83 Frequency converter 84 Symbol data Timing generator 85 switch control unit 86 selector switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Suzuki 2-3-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Yusuke Asai 2-3-3 Otemachi, Chiyoda-ku, Tokyo No. 1 F-term in Nippon Telegraph and Telephone Corporation (reference) 5K022 DD01 DD23 DD33 5K067 AA02 CC24 HH21 KK03

Claims (29)

[Claims] An OFD including a plurality of N transmit antennas
An M signal transmitting apparatus and an O including a plurality of N receiving antennas
An OFDM signal transmission system comprising an FDM signal receiving device, wherein the OFDM signal transmitting device transmits an OFDM signal of the same radio frequency from the N transmitting antennas, wherein each of the N transmitting antennas and the N Inverse matrix calculating means for calculating an inverse matrix of a matrix composed of N × N elements having a transmission coefficient in each signal transmission path between each of the plurality of receiving antennas as components, and the inverse matrix calculating means Based on the inverse matrix
An interference canceling means for separating a signal on each signal transmission path between each of the N transmitting antennas and each of the N receiving antennas.
FDM signal transmission system. 2. A system comprising a plurality of N transmitting antennas and a plurality of N receiving antennas, wherein the system is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing. OFDM
A frequency converter connected to a modulator and a transmitting antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; At least one OFDM signal transmitting device connected to the OFDM modulator and having means for multiplexing the transmission information signal and the pilot signal, and supplying a common OFDM symbol timing to all of the OFDM modulators related to the OFDM signal transmitting device. A local oscillator that supplies a common local oscillation signal to all of the frequency converters of the OFDM signal transmitting apparatus; a local oscillator that is connected to each receiving antenna and demodulates a radio frequency reception signal using the local oscillation frequency. Frequency converter for converting the frequency to a frequency suitable for the frequency converter and OFDM modulation connected to the frequency converter respectively The reception amplitude and phase of the pilot signal are known for all combinations of the fast Fourier transformer and the transmission antenna and the reception antenna that operate based on the timing signal for receiving the pilot signal transmitted corresponding to each reception antenna at the reception antenna. Inverse matrix operation means for measuring a transfer coefficient by normalizing with a pilot signal amplitude / phase, calculating and storing an inverse matrix for a matrix related to each subcarrier, and each received OFDM signal as an output of a fast Fourier transformer, and At least one OFDM signal receiving device having a subcarrier demodulating means for taking the product of the subcarriers and the inverse matrix and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal; and the OFDM signal receiving device A local oscillator for supplying a common local oscillation signal to all of the frequency converters according to the above, An OFDM signal transmission system comprising timing signal generating means for receiving, by a receiving antenna, a pilot signal transmitted corresponding to each OFDM modulator according to the OFDM signal receiving apparatus. 3. A transmitting apparatus used in the OFDM signal transmission system according to claim 2, wherein the transmitting apparatus is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a modulator and a transmitting antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; An OFDM signal transmitting apparatus connected to an OFDM modulator and having means for multiplexing a transmission information signal and the pilot signal. 4. A receiving apparatus used in the OFDM signal transmission system according to claim 2, wherein the receiving apparatus is connected to each receiving antenna, and uses a local oscillation frequency to convert a radio frequency received signal to a frequency suitable for demodulation. Frequency converter, and a high-speed Fourier transformer, and a transmitting antenna and a receiving antenna, each of which operates based on a timing signal for receiving at a receiving antenna a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator. Inverting matrix calculation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, measuring the transfer coefficient, and calculating and storing the inverse matrix for the matrix related to each subcarrier for all combinations of And each received OFDM signal output from the fast Fourier transformer and associated with an arbitrary subcarrier. Taking the product of things and the inverse matrix, OF with subcarrier demodulation means for outputting the subcarrier amplitude and phase of each transmission OFDM signal
DM signal receiving device. 5. The OFDM signal transmission system according to claim 2, wherein two transmission antennas using mutually orthogonal polarizations are used as transmission antennas, and two reception antennas using mutually orthogonal polarizations are used as reception antennas. 6. A transmission apparatus used in the OFDM signal transmission system according to claim 5, wherein the transmission apparatus is connected to each transmission antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a modulator and a transmitting antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; An OFDM signal transmitting apparatus connected to an OFDM modulator and having means for multiplexing a transmission information signal and the pilot signal. 7. A receiving apparatus used in the OFDM signal transmission system according to claim 5, wherein the receiving apparatus is connected to each receiving antenna, and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency. Frequency converter, and a high-speed Fourier transformer, and a transmitting antenna and a receiving antenna, each of which operates based on a timing signal for receiving at a receiving antenna a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator. Inverting matrix calculation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, measuring the transfer coefficient, and calculating and storing the inverse matrix for the matrix related to each subcarrier for all combinations of And each received OFDM signal output from the fast Fourier transformer and associated with an arbitrary subcarrier. Taking the product of things and the inverse matrix, OF with subcarrier demodulation means for outputting the subcarrier amplitude and phase of each transmission OFDM signal
DM signal receiving device. 8. A system comprising a plurality of N transmitting antennas and a plurality of N receiving antennas, wherein the system is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing. OFDM
A frequency converter connected to a modulator and a transmitting antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; Means for multiplexing a transmission information signal and the pilot signal connected to the OFDM modulator, an error correction encoder for performing error correction coding on the transmission information, and an output of the error correction device, a combination of the OFDM modulator and the subcarrier At least one OFDM signal transmission device having an interleaver for performing interleaving by: a means for supplying a common OFDM symbol timing to all of the OFDM modulators according to the OFDM signal transmission device; and a frequency converter according to the OFDM signal transmission device. Local oscillator that supplies a common local oscillation signal to all the Connected to each other, and is connected to the frequency converter to convert the received signal of the radio frequency to a frequency suitable for demodulation using the local oscillation frequency, and is transmitted corresponding to each OFDM modulator. For a fast Fourier transformer that operates based on a timing signal for receiving a pilot signal at a receiving antenna, and for all combinations of a transmitting antenna and a receiving antenna, normalize the received amplitude and phase of the pilot signal with a known pilot signal amplitude and phase. Matrix coefficient, and calculates and stores an inverse matrix with respect to a matrix related to each subcarrier, and each received OFDM signal as an output of a fast Fourier transformer, which is related to an arbitrary subcarrier, and Subcarrier for taking the product of the inverse matrix and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal At least one OFD having deinterleaver and and error correction decoder for decoding the error correction code for performing the reverse operation and the input interleaver the demodulated output of the demodulation means and the subcarrier demodulation means
An M signal receiving apparatus; a local oscillator that supplies a local oscillation signal common to all of the frequency converters according to the OFDM signal receiving apparatus; and a local oscillator that transmits a signal corresponding to each OFDM modulator according to the OFDM signal receiving apparatus. An OFDM signal transmission system comprising timing signal generating means for receiving a pilot signal by a receiving antenna. 9. A transmission apparatus used in the OFDM signal transmission system according to claim 8, wherein the transmission apparatus is connected to each transmission antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a modulator and a transmitting antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; Means for multiplexing a transmission information signal and the pilot signal connected to the OFDM modulator, an error correction encoder for performing error correction coding on the transmission information, and an output of the error correction device, a combination of the OFDM modulator and the subcarrier OFDM signal transmitting apparatus having an interleaver for performing interleaving by the OFDM signal. 10. A receiving apparatus used in the OFDM signal transmission system according to claim 8, wherein the receiving apparatus is connected to each receiving antenna, and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency. Frequency converter, and a high-speed Fourier transformer, and a transmitting antenna and a receiving antenna, each of which operates based on a timing signal for receiving at a receiving antenna a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator. Inverting matrix calculation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, measuring the transfer coefficient, and calculating and storing the inverse matrix for the matrix related to each subcarrier for all combinations of And each received OFDM signal, which is the output of the fast Fourier transformer, on any subcarrier And a deinterleaver that takes the product of the inverse matrix and outputs the amplitude and phase of the subcarrier of each transmission OFDM signal, and a deinterleaver that receives the demodulated output of the subcarrier demodulator as an input and performs the inverse operation of the interleaver. And an error correction decoder for decoding the error correction code. 11. The OFDM signal transmission system according to claim 8, wherein two transmission antennas using mutually orthogonal polarizations are used as transmission antennas, and two reception antennas using mutually orthogonal polarizations are used as reception antennas. 12. A transmitting apparatus used in the OFDM signal transmission system according to claim 11, wherein the transmitting apparatus is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a modulator and a transmission antenna for converting an output of the OFDM modulator to a radio frequency using a local oscillation frequency; a means for generating a known pilot signal corresponding to each of the OFDM modulators; A means connected to each OFDM modulator for multiplexing the transmission information signal and the pilot signal, an error correction encoder for performing error correction coding on the transmission information, and an output of the error correction device are output to the OFDM modulator and the subcarriers. An OFDM signal transmission device having an interleaver that performs interleaving by combination. 13. A receiving apparatus used in the OFDM signal transmission system according to claim 11, wherein the receiving apparatus is connected to each receiving antenna and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency. Frequency converter, and a high-speed Fourier transformer, and a transmitting antenna and a receiving antenna, each of which operates based on a timing signal for receiving at a receiving antenna a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator. Inverting matrix calculation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, measuring the transfer coefficient, and calculating and storing the inverse matrix for the matrix related to each subcarrier for all combinations of And each of the received OFDM signals output from the fast Fourier transformer, and A subcarrier demodulation means for taking the product of the inverse matrix and the inverse matrix and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal; and a deinterleaver for performing an operation reverse to the interleaver with the demodulated output of the subcarrier demodulation means as an input. And an OFDM signal receiving apparatus having an error correction decoder for decoding the error correction code. 14. A system comprising a plurality of N transmitting antennas and a plurality of N receiving antennas, wherein the system is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing. OFDM
A frequency converter connected to a modulator and a transmission antenna for converting the output of the OFDM modulator to a radio frequency using a local oscillation frequency; and switching and transmitting a signal obtained by serial-to-parallel conversion of a transmission information signal or the same transmission information signal. A switch, means for generating a known pilot signal corresponding to each of the OFDM modulators, means for multiplexing the transmission information signal and the pilot signal connected to each of the OFDM modulators, and error correction for the transmission information At least one OFDM signal transmitting apparatus having an interleaver for performing interleaving of an output of an error correction encoder and an error corrector for performing encoding by a combination of an OFDM modulator and a subcarrier; and an OFDM modulator according to the OFDM signal transmitting apparatus. Means for supplying a common OFDM symbol timing to all OFDM signals; A local oscillator that supplies a common local oscillation signal to all of the frequency converters related to the device, and is connected to each of the receiving antennas, and uses the local oscillation frequency to frequency-convert a radio frequency reception signal to a frequency suitable for demodulation. A frequency converter and a fast Fourier transformer connected to the frequency converter and operated based on a timing signal for receiving a pilot signal transmitted corresponding to each OFDM modulator by a reception antenna; and a transmission antenna and a reception antenna. Inverse matrix operation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase for all combinations, measuring the transfer coefficient, calculating and storing the inverse matrix for the matrix related to each subcarrier, and Each received OFDM signal, which is the output of the fast Fourier transformer, is related to an arbitrary subcarrier, and A sub-carrier demodulation means for taking the product of the inverse matrix and outputting the amplitude and phase of the sub-carrier of each transmission OFDM signal, a deinterleaver for receiving the demodulated output of the sub-carrier demodulation means as input, and performing an operation reverse to the interleaver; An error correction decoder for decoding the code, a means for measuring the reception quality of the output of the subcarrier demodulation means relating to any subcarrier of the transmission OFDM signal, and a case where the transmission side transmits a signal obtained by serial-to-parallel conversion of the transmission information signal. Output a subcarrier demodulated output and add the subcarrier demodulated output when transmitting the same transmission information signal, or at least one OFDM having a switch for outputting the higher received level of the subcarrier demodulated output A local oscillation signal common to all of the signal receiver and the frequency converter related to the OFDM signal receiver. And a timing signal generating means for receiving, by a receiving antenna, a pilot signal transmitted corresponding to each OFDM modulator according to the OFDM signal receiving apparatus. Signal transmission system. 15. A transmission apparatus used in the OFDM signal transmission system according to claim 14, wherein the transmission apparatus is connected to each transmission antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a modulator and a transmission antenna for converting the output of the OFDM modulator to a radio frequency using a local oscillation frequency; and switching and transmitting a signal obtained by serial-to-parallel conversion of a transmission information signal or the same transmission information signal. A switch, means for generating a known pilot signal corresponding to each of the OFDM modulators, means for multiplexing the transmission information signal and the pilot signal connected to each of the OFDM modulators, and error correction for the transmission information An OFDM signal transmitting apparatus having an error correction encoder for performing encoding and an interleaver for interleaving the output of the error corrector with a combination of an OFDM modulator and a subcarrier. 16. A receiving device used in the OFDM signal transmission system according to claim 14, wherein the receiving device is connected to each receiving antenna and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency. Frequency converter, and a high-speed Fourier transformer, and a transmitting antenna and a receiving antenna, each of which operates based on a timing signal for receiving at a receiving antenna a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator. Inverting matrix calculation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, measuring the transfer coefficient, and calculating and storing the inverse matrix for the matrix related to each subcarrier for all combinations of And each of the received OFDM signals output from the fast Fourier transformer, and A subcarrier demodulation means for taking the product of the inverse matrix and the inverse matrix and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal; and a deinterleaver for performing an operation reverse to the interleaver with the demodulated output of the subcarrier demodulation means as an input. And an error correction decoder for decoding the error correction code, a means for measuring the reception quality of the output of the subcarrier demodulation means relating to any subcarrier of the transmission OFDM signal, and a signal obtained by serial-to-parallel conversion of the transmission information signal on the transmission side. It has a switch that outputs a subcarrier demodulation output when transmitting, and adds a subcarrier demodulation output when outputting the same transmission information signal, or outputs a higher reception level of the subcarrier demodulation output. OFDM signal receiving device. 17. The OFDM signal transmission system according to claim 14, wherein two transmission antennas using mutually orthogonal polarizations are used as transmission antennas, and two reception antennas using mutually orthogonal polarizations are used as reception antennas. 18. A transmitting apparatus used in the OFDM signal transmission system according to claim 17, wherein the transmitting apparatus is connected to each transmitting antenna, uses the same radio frequency, and operates based on symbol timing.
A frequency converter connected to a modulator and a transmission antenna for converting the output of the OFDM modulator to a radio frequency using a local oscillation frequency; and switching and transmitting a signal obtained by serial-to-parallel conversion of a transmission information signal or the same transmission information signal. A switch, means for generating a known pilot signal corresponding to each of the OFDM modulators, means for multiplexing the transmission information signal and the pilot signal connected to each of the OFDM modulators, and error correction for the transmission information An OFDM signal transmitting apparatus having an error correction encoder for performing encoding and an interleaver for interleaving the output of the error corrector with a combination of an OFDM modulator and a subcarrier. 19. A receiving apparatus used in the OFDM signal transmission system according to claim 17, wherein the receiving apparatus is connected to each receiving antenna and converts a received signal of a radio frequency into a frequency suitable for demodulation using a local oscillation frequency. Frequency converter, and a high-speed Fourier transformer, and a transmitting antenna and a receiving antenna, each of which operates based on a timing signal for receiving at a receiving antenna a pilot signal connected to the frequency converter and transmitted corresponding to each OFDM modulator. Inverting matrix calculation means for normalizing the reception amplitude and phase of the pilot signal with the known pilot signal amplitude and phase, measuring the transfer coefficient, and calculating and storing the inverse matrix for the matrix related to each subcarrier for all combinations of And each of the received OFDM signals output from the fast Fourier transformer, and A subcarrier demodulation means for taking the product of the inverse matrix and the inverse matrix and outputting the amplitude and phase of the subcarrier of each transmission OFDM signal; and a deinterleaver for performing an operation reverse to the interleaver with the demodulated output of the subcarrier demodulation means as an input. And an error correction decoder for decoding the error correction code, means for measuring the reception quality of the output of the subcarrier demodulation means relating to any subcarrier of the transmission OFDM signal, and a signal obtained by serial-parallel conversion of the transmission information signal on the transmission side. A switch that outputs a subcarrier demodulation output when transmitting the same transmission information, and adds a subcarrier demodulation output when outputting the same transmission information signal, or outputs a subcarrier demodulation output with a higher reception level. OFDM signal receiving apparatus comprising: 20. An OF including a plurality of N transmit antennas
An OFDM signal transmission system comprising: a DM signal transmission device; and an OFDM signal reception device including a plurality of N reception antennas, wherein the OFDM signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas. In the OFDM signal transmitting apparatus, a known N corresponding to each of the N transmitting antennas is provided.
Pilot signal generating means for generating various kinds of pilot signals, N data converting means for converting each of the N input transmission data into OFDM symbols, and information on an inverse matrix transmitted from the OFDM signal receiving apparatus An inverse matrix receiving means for receiving the OFDM symbol generated by the data converting means, and a pre-interference canceling means for multiplying each subcarrier of the OFDM symbol by the inverse matrix obtained by the inverse matrix receiving means; N signals output from the pilot signal generating means are added to each of the N systems of signals output from the interference canceling means.
N multiplexing means for multiplexing the pilot signals of the different types; N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the N multiplexing means; OF common to all inverse Fourier transform means
Symbol timing generating means for providing DM symbol timing; N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency; and all of the N transmitting frequency converting means And a local oscillation means for transmitting a common local oscillation signal to the OFDM signal receiving apparatus. The OFDM signal receiving apparatus further includes a radio frequency (N) converter for converting a radio frequency reception signal received by the N reception antennas into a frequency suitable for demodulation. Receiving frequency converting means, receiving local oscillating means for providing a common local oscillation signal to all of the N receiving frequency converting means, and N systems output by the N receiving frequency converting means. N fast Fourier transform means for performing a Fourier transform process on each of the received signals; and an OFDM signal output from the fast Fourier transform means. N demodulating means for converting a received signal into a bit string, and a timing signal generating means for generating a timing signal required to extract from the received signal the N pilot signals transmitted via each of the N transmitting antennas Means; and N received at the output of said Fast Fourier Transform means.
From the pilot signals, and detects the amplitude and phase for each subcarrier, and based on the detected amplitude and phase, N × N corresponding to each combination of the N transmission antennas and the N reception antennas Inverse matrix computing means for computing an inverse matrix of a matrix constituted by transfer coefficients of elements; and information of the inverse matrix obtained by the inverse matrix computing means is transmitted to the OFD.
An OFDM signal transmission system, comprising: an inverse matrix information transmitting means for transmitting to an M signal transmitting apparatus. 21. An OF including a plurality of N transmit antennas
An OFDM signal transmission system comprising: a DM signal transmission device; and an OFDM signal reception device including a plurality of N reception antennas, wherein the OFDM signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas. An OFDM signal transmission device used for the N transmission antennas, wherein a known N corresponding to each of the N transmission antennas
Pilot signal generating means for generating various kinds of pilot signals, N data converting means for converting each of the N input transmission data into OFDM symbols, and information on an inverse matrix transmitted from the OFDM signal receiving apparatus An inverse matrix receiving means for receiving the OFDM symbol generated by the data converting means, and a pre-interference canceling means for multiplying each subcarrier of the OFDM symbol by the inverse matrix obtained by the inverse matrix receiving means; N signals output from the pilot signal generating means are added to each of the N systems of signals output from the interference canceling means.
N multiplexing means for multiplexing the pilot signals of the different types; N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the N multiplexing means; OF common to all inverse Fourier transform means
Symbol timing generating means for providing DM symbol timing; N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency; and all of the N transmitting frequency converting means And a transmission local oscillation means for providing a common local oscillation signal to the OFDM signal transmission apparatus. 22. An OF comprising a plurality of N transmit antennas
An OFDM signal transmission system comprising: a DM signal transmission device; and an OFDM signal reception device including a plurality of N reception antennas, wherein the OFDM signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas. An OFDM signal receiving apparatus used for: N receiving frequency conversion means for converting a reception signal of a radio frequency received by the N receiving antennas into a frequency suitable for demodulation; and the N receiving frequencies. A local oscillation means for receiving which supplies a common local oscillation signal to all of the conversion means; and N high-speed processing means for performing Fourier transform processing on each of the N-system reception signals output from the N reception frequency conversion means. Fourier transforming means; N demodulating means for transforming an OFDM symbol output from the fast Fourier transforming means into a bit sequence; And timing signal generating means for generating a timing signal necessary to extract the N pilot signal transmitted over a respective antenna from the received signal, said received at the output of the fast Fourier transform means N
From the pilot signals, and detects the amplitude and phase for each subcarrier, and based on the detected amplitude and phase, N × N corresponding to each combination of the N transmission antennas and the N reception antennas Inverse matrix computing means for computing an inverse matrix of a matrix constituted by transfer coefficients of elements; and information of the inverse matrix obtained by the inverse matrix computing means is transmitted to the OFD.
An OFDM signal receiving apparatus comprising: an inverse matrix information transmitting means for transmitting to an M signal transmitting apparatus. 23. An OF including a plurality of N transmit antennas
An OFDM signal transmission system comprising: a DM signal transmission device; and an OFDM signal reception device including a plurality of N reception antennas, wherein the OFDM signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas. In the OFDM signal transmitting apparatus, a known N corresponding to each of the N transmitting antennas is provided.
Pilot signal generating means for generating various kinds of pilot signals, N data converting means for converting each of the input N transmission data into OFDM symbols, reception of a pilot signal transmitted from the OFDM signal receiving apparatus Information receiving means for receiving information; and the OF based on the information received by the information receiving means.
The amplitude and phase of the N pilot signals received by the DM signal receiving device are detected for each subcarrier, and based on the detected amplitude and phase, the N transmission antennas and the N reception antennas are combined. Inverse matrix computing means for computing an inverse matrix of a matrix composed of corresponding N × N elements of transfer coefficients; and performing the inverse matrix computation for each subcarrier of each OFDM symbol generated by the data conversion means. A pre-interference canceling means for multiplying the inverse matrix obtained by the means; and N signals output from the pilot signal generating means for each of N signals output from the pre-interference canceling means.
N multiplexing means for multiplexing the pilot signals of the different types; N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the N multiplexing means; OF common to all inverse Fourier transform means
Symbol timing generating means for providing DM symbol timing; N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency; and all of the N transmitting frequency converting means And a local oscillation means for transmitting a common local oscillation signal to the OFDM signal receiving apparatus. The OFDM signal receiving apparatus further includes a radio frequency (N / N) converting signal received by the N receiving antennas into a frequency suitable for demodulation. Receiving frequency converting means, receiving local oscillating means for providing a common local oscillation signal to all of the N receiving frequency converting means, and N systems output by the N receiving frequency converting means. N fast Fourier transform means for performing a Fourier transform process on each of the received signals; and an OFDM signal output from the fast Fourier transform means. N demodulating means for converting a received signal into a bit string, and a timing signal generating means for generating a timing signal required to extract from the received signal the N pilot signals transmitted via each of the N transmitting antennas Means, and information transmitting means for detecting the amplitude and phase of the received N pilot signals for each subcarrier from the output of the fast Fourier transform means, and transmitting the detected information to the OFDM signal transmitting apparatus. OF characterized by being provided
DM signal transmission system. 24. An OF including a plurality of N transmit antennas
An OFDM signal transmission system comprising: a DM signal transmission device; and an OFDM signal reception device including a plurality of N reception antennas, wherein the OFDM signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas. An OFDM signal transmission device used for: N known antennas corresponding to each of the N transmission antennas
Pilot signal generating means for generating various kinds of pilot signals, N data converting means for converting each of the input N transmission data into OFDM symbols, reception of a pilot signal transmitted from the OFDM signal receiving apparatus Information receiving means for receiving information; and the OF based on the information received by the information receiving means.
The amplitude and phase of the N pilot signals received by the DM signal receiving device are detected for each subcarrier, and based on the detected amplitude and phase, the N transmission antennas and the N reception antennas are combined. Inverse matrix computing means for computing an inverse matrix of a matrix composed of corresponding N × N elements of transfer coefficients; and performing the inverse matrix computation for each subcarrier of each OFDM symbol generated by the data conversion means. A pre-interference canceling means for multiplying the inverse matrix obtained by the means; and N signals output from the pilot signal generating means for each of N signals output from the pre-interference canceling means.
N multiplexing means for multiplexing the pilot signals of the different types; N fast inverse Fourier transform means for performing an inverse Fourier transform on the signals output from the N multiplexing means; OF common to all inverse Fourier transform means
Symbol timing generating means for providing DM symbol timing; N transmitting frequency converting means for converting the frequency of the signal output from the fast inverse Fourier transform means to a radio frequency; and all of the N transmitting frequency converting means And a transmission local oscillation means for providing a common local oscillation signal to the OFDM signal transmission apparatus. 25. An OF including a plurality of N transmit antennas
An OFDM signal transmission system comprising: a DM signal transmission device; and an OFDM signal reception device including a plurality of N reception antennas, wherein the OFDM signal transmission device transmits an OFDM signal of the same radio frequency from the N transmission antennas. An OFDM signal receiving apparatus used for: N receiving frequency conversion means for converting a reception signal of a radio frequency received by the N receiving antennas into a frequency suitable for demodulation; and the N receiving frequencies. A local oscillation means for receiving which supplies a common local oscillation signal to all of the conversion means; and N high-speed processing means for performing Fourier transform processing on each of the N-system reception signals output from the N reception frequency conversion means. Fourier transforming means; N demodulating means for transforming an OFDM symbol output from the fast Fourier transforming means into a bit sequence; Timing signal generating means for generating a timing signal required to extract from the received signal the N pilot signals transmitted through each of the teners; and N pilot signals received from the output of the fast Fourier transform means. Information transmitting means for detecting an amplitude and a phase of a signal for each subcarrier and transmitting the detected information to the OFDM signal transmitting apparatus.
DM signal receiving device. 26. The OFDM according to claim 20 or 23.
In the signal transmission system, the OFDM signal receiving apparatus further includes at least one information transmitting antenna, and the OFDM signal transmitting apparatus further includes at least one information receiving antenna.
DM signal transmission system. 27. An OFDM signal transmitting apparatus including a plurality of N first sets of antennas, and an OFDM signal receiving apparatus including a plurality of N second sets of antennas, wherein the OFDM signal receiving apparatus includes a plurality of N second sets of antennas.
An OFDM signal transmission system in which a signal transmission device transmits an OFDM signal of the same radio frequency from the N first sets of antennas, wherein the OFDM signal reception device corresponds to each of the first sets of antennas. Pilot signal generating means for generating the known N kinds of pilot signals, N inverse fast Fourier transform means for performing inverse fast Fourier transform on the N kinds of pilot signals output from the pilot signal generating means, N transmission frequency conversion means for converting a signal output from the inverse fast Fourier transform means into a radio frequency for transmission, and a frequency suitable for demodulating a radio frequency reception signal received by the second set of antennas N receiving frequency converting means for converting the signals into: N receiving signals of each of N systems output by the N receiving frequency converting means N fast Fourier transform means for performing a Fourier transform process; N demodulation means for converting an OFDM symbol output from the fast Fourier transform means into a bit sequence; N transmission frequency transform means and N Local oscillation means for providing a common signal to all of the reception frequency conversion means, and transmission / reception switch means for switching between transmission and reception with respect to the N second set of antennas,
The OFDM signal transmitting apparatus includes: N number of data converting means for converting each of the input N-system transmission data into an OFDM symbol; and the OFDM signal receiving apparatus transmits the OFDM signal received by the first set of antennas. N number of receiving frequency converting means for converting a radio frequency pilot signal into a frequency suitable for demodulation, N number of fast Fourier transforming means for performing Fourier transform on a signal output from the receiving frequency converting means, Timing signal generating means for generating, from a received signal output by the fast Fourier transform means, a timing signal necessary to extract each of the N pilot signals transmitted via the second set of antennas; On the basis of the signal extracted from the output of the fast Fourier transform means, N
The amplitudes and phases of the pilot signals are detected for each subcarrier, and based on the detected amplitudes and phases, the pilot signals correspond to the respective combinations of the N first set antennas and the N second set antennas. Matrix operation means for calculating an inverse matrix of a matrix composed of N × N elements of transfer coefficients, and said inverse matrix calculation means for each subcarrier of each OFDM symbol generated by said data conversion means. Pre-interference canceling means for performing multiplication of the inverse matrix obtained in the above, N fast inverse Fourier transform means for performing an inverse Fourier transform on a signal output from the pre-interference canceling means, and the fast inverse Fourier transform means N transmission frequency conversion means for converting the frequency of the signal output from the radio signal to a radio frequency, and common to all of the N transmission frequency conversion means and the N reception frequency conversion means OFDM signal transmission system is characterized by providing a local oscillator means for providing a part oscillating signal, and a transmission and reception change-over switch means for switching between transmission and reception for said N first set of antennas. 28. An OFDM signal transmitting apparatus including a plurality of N first sets of antennas, and an OFDM signal receiving apparatus including a plurality of N second sets of antennas, wherein the OFDM signal receiving apparatus includes a plurality of N second sets of antennas.
An OFDM signal receiving apparatus for use in an OFDM signal transmission system in which a signal transmitting apparatus transmits OFDM signals of the same radio frequency from said first antennas of said N pieces, said known apparatus corresponding to each of said first sets of antennas. Pilot signal generating means for generating N kinds of pilot signals, N inverse fast Fourier transform means for performing an inverse fast Fourier transform on the N kinds of pilot signals output from the pilot signal generating means, N transmitting frequency converting means for converting a signal output from the Fourier transform means into a radio frequency for transmission, and converting a radio frequency received signal received by the second set of antennas into a frequency suitable for demodulation. N receiving frequency conversion means for performing the processing, and N reception signals output from the N receiving frequency converting means for each of the N reception signals. N fast Fourier transform means for performing a Rier transform process; N demodulation means for converting an OFDM symbol output from the fast Fourier transform means into a bit string; N transmission frequency transform means and N An OFDM signal reception apparatus comprising: a local oscillation means for providing a common signal to all of the reception frequency conversion means; and a transmission / reception switch means for switching between transmission and reception for the N second set of antennas. apparatus. 29. An OFDM signal transmitting apparatus including a plurality of N first sets of antennas and an OFDM signal receiving apparatus including a plurality of N second sets of antennas, wherein the OFDM signal receiving apparatus includes a plurality of N second sets of antennas.
An OFDM signal transmission apparatus for use in an OFDM signal transmission system in which a signal transmission apparatus transmits an OFDM signal of the same radio frequency from the N first set of antennas, the OFDM signal transmission apparatus comprising: N data converting means for converting into symbols, N receiving frequencies for converting a radio frequency pilot signal transmitted from the OFDM signal receiving apparatus and received by the first set of antennas to a frequency suitable for demodulation Converting means; N fast Fourier transform means for performing Fourier transform on a signal output from the receiving frequency converting means; and a receiving signal output from the fast Fourier transform means via the second set of antennas. Signal generating means for generating a timing signal necessary to extract each of the N pilot signals transmitted by And N based on the signal extracted from the output of the fast Fourier transform means transmitted from the OFDM signal transmitting apparatus.
The amplitudes and phases of the pilot signals are detected for each subcarrier, and based on the detected amplitudes and phases, the pilot signals correspond to the respective combinations of the N first set antennas and the N second set antennas. Matrix operation means for calculating an inverse matrix of a matrix composed of N × N elements of transfer coefficients, and said inverse matrix calculation means for each subcarrier of each OFDM symbol generated by said data conversion means. Pre-interference canceling means for multiplying the inverse matrix obtained by the above, N fast inverse Fourier transform means for performing an inverse Fourier transform on a signal output from the pre-interference canceling means, and the fast inverse Fourier transform means N transmission frequency conversion means for converting the frequency of the signal output from the radio signal to a radio frequency, and common to all of the N transmission frequency conversion means and the N reception frequency conversion means A local oscillator means for providing a part oscillating signal, said N first set of OFDM signal transmitting apparatus characterized in that a transmission and reception change-over switch means for switching between transmission and reception for the antenna.