JP2013236227A - Transmitter, receiver, transmission program, reception program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter which can transmit data subjected to block coding, without causing reduction in transmission capacity and degradation in estimation precision of transmission path response.SOLUTION: A transmitter 100 for transmitting data by OFDM signals consists of an OFDM modulation unit 150 including a block coding section 140 for generating a data block consisting of N (N is a positive integer of 2 or more) pieces of data, a pilot signal generating section generating a pilot signal for transmission path response estimation, and an OFDM symbol configuring section for configuring the OFDM symbol of an OFDM signal by the data block and pilot signal. The OFDM symbol configuring section arranges the pilot signals so that the data block is assigned to the adjacent data carrier symbol of the OFDM symbol.

Description

  The present invention relates to a transmission apparatus that transmits data using an OFDM (Orthogonal Frequency Division Multiplexing) signal, a reception apparatus that receives data transmitted from the transmission apparatus, a transmission program, and a reception program. .

  In a system that transmits data using a plurality of OFDM signals in the same frequency band, a method is known in which a pilot signal of one OFDM signal is made non-signal and a transmission path response of another OFDM signal is estimated. (For example, refer to Patent Document 1).

  FIG. 25 is a block diagram showing an OFDM transmission system that performs 2 × 2 MIMO (Multi Input Multi Output) transmission. The OFDM transmission system includes a transmission device 12 having two transmission antennas 11-1 and 11-2 and a reception device 22 having two reception antennas 21-1 and 21-2. The pilot signal pattern 1 is transmitted from the transmission antenna 11-1, and the pilot signal pattern 2 is transmitted from the transmission antenna 11-2.

  FIG. 26 is a diagram showing an arrangement of pilot patterns in the case of FIG. In FIG. 26, a portion indicated by “1” is a pilot signal having a significant value, and a portion indicated by “0” is no signal. In FIG. 26, if a pilot signal at symbol number s and carrier (subcarrier) number c is P (s, c), in pattern 1, transmission at positions P (1, 1) and P (2, 2) is performed. The path response is obtained, and in pattern 2, the transmission path responses at the positions of P (1,2) and P (2,1) are obtained.

  FIG. 27 is a block diagram illustrating an OFDM transmission system that performs 4 × 4 MIMO transmission. This OFDM transmission system includes a transmission device 32 having four transmission antennas 31-1 to 31-4 and a reception device 42 having four reception antennas 41-1 to 41-4. Four patterns of pilot signals are transmitted from the four transmission antennas 31-1 to 31-4. 27 illustrates the case where the reception device 42 includes four reception antennas 41-1 to 41-4, the number of reception antennas may be other than four.

  FIG. 28 shows an arrangement of pilot patterns in the case of FIG. 27, and shows an example in which pilot signals are arranged linearly in the symbol direction. As in the case of FIG. 26, the part indicated by “1” is a pilot signal having a certain significant value, and the part indicated by “0” is no signal. In FIG. 28, pilot signals are inserted in different carriers of four OFDM signals, and other OFDM signals are non-signaled in a section in which one OFDM signal transmits a pilot signal. Therefore, the transmission line response can be obtained without performing a special calculation. In the case of FIG. 28, four transmission path responses can be obtained in a 4 symbol × 4 carrier section.

  On the other hand, three methods are generally known as methods for arranging pilot signals in OFDM symbols. The first scheme is a continuous pilot (CP) scheme. In the CP scheme, as shown in FIG. 29, pilot signals are arranged continuously in a symbol direction (time direction) on a specific carrier. FIG. 29 illustrates a case where pilot signals are arranged at a rate of once per 8 carriers.

  The second scheme is a pilot symbol scheme. In the pilot symbol scheme, as shown in FIG. 30, pilot signals are arranged continuously in a carrier direction (frequency direction) at a specific symbol. FIG. 30 illustrates a case where pilot signals are arranged at a rate of once per four symbols.

  The third method is a scattered pilot (SP) method. In the SP method, as shown in FIG. 31, pilot signals are distributed and arranged in a specific carrier and symbol. FIG. 31 illustrates a case where pilot signals are arranged once every 12 carriers, once every 4 symbols. The SP system is also employed in a transmission system (ARIB STD-B31) for terrestrial digital television broadcasting. Note that the method of arranging pilot signals is not limited to the above three methods.

  As described above, in a system that transmits data using a plurality of OFDM signals at the same frequency, it is necessary to determine the arrangement of pilot signals in advance as shown in FIGS. In the transmission apparatus, a specific value is assigned to the determined arrangement based on the pilot pattern as shown in FIG. 26 or FIG. In the receiving apparatus, the transmission path response is estimated based on a pilot pattern having a predetermined pilot signal arrangement.

By the way, for example, Alamouti space-time block coding (STBC) is known as block coding of data transmitted by an OFDM signal. The Alamouti space-time block coding matrix is expressed by the following equation (1). In the formula (1), ^* represents a complex conjugate.

  In Equation (1), the row of the matrix A corresponds to the transmission antenna number. Therefore, the matrix A is used when signals are transmitted by two transmission antennas as shown in FIG. The column of the matrix A corresponds to the symbol number (time). When transmitting the space-time block-encoded data based on Equation (1) using a plurality of OFDM signals, the transmission / reception apparatus needs to determine the arrangement of pilot signals.

  For example, when data is transmitted by the SP method shown in FIG. 31, the space-time block coded data is allocated to the position indicated as “data” in FIG. Therefore, when signals are transmitted by two transmission antennas as shown in FIG. 25, the data transmitted from the respective antennas is expressed as “data” as shown by antenna 1 and antenna 2 in FIG. Will be allocated to the current location.

  Here, in the space-time block coding of Equation (1), two OFDM symbols are processed as a set. Therefore, in the case of FIG. 32, symbol numbers (1, 2) are a pair, and (3, 4), (5, 6),. FIG. 32 shows an example of data assigned to carrier number 2 and symbol number (1, 2).

  However, in the positions indicated by “x” in FIG. 32, pilot signals are arranged at the positions that form a pair. Therefore, space-time block encoded data cannot be assigned to the position indicated by “x”. With respect to this point, a method of arranging a pilot signal at a position indicated by “x” in FIG. 32 is known (see, for example, Patent Document 2). However, with this method, it is possible to improve the estimation accuracy of the channel response obtained by the receiving device as the pilot signal increases, but the ratio of the pilot signal to the total signal increases, so the data transmission capacity Will drop. Similar problems also occur when transmitting spatial frequency block coded data.

JP 2004-96186 A Special table 2008-533801 gazette

  Accordingly, an object of the present invention made in view of the above-described viewpoint is to provide a transmission device capable of transmitting block-coded data without causing a reduction in transmission capacity and a reduction in estimation accuracy of a transmission path response, and the transmission device. It is to provide a receiving device that receives data transmitted from the network, a transmission program, and a reception program.

  In order to solve the above-described problem, a transmitting apparatus according to the present invention is a transmitting apparatus that transmits data using an OFDM signal, and generates a data block including N (N is a positive integer of 2 or more) pieces of data. An encoding unit, a pilot signal generation unit that generates a pilot signal for channel response estimation, and an OFDM symbol configuration unit that configures an OFDM symbol of the OFDM signal by the data block and the pilot signal, The OFDM symbol configuration unit arranges the pilot signal so that the data block is allocated to a data carrier symbol adjacent to the OFDM symbol.

  Further, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that is space-time block encoded, and the OFDM symbol configuration unit is configured such that the data block including N pieces of data is in a symbol direction. The pilot signals are arranged by a continuous pilot system so that M (M is a positive integer) are continuously assigned to the.

  Further, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that has been subjected to space-time block encoding, and the OFDM symbol configuration unit performs (N × M + 1) symbols ( The pilot signal is arranged at a rate of once every (M is a positive integer).

  Further, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that is space-time block encoded, and the OFDM symbol configuration unit is (N × M + 1) according to a scattered pilot scheme. The pilot signal is arranged so that the amount of shift in the symbol direction is 0 at a rate of once per symbol (M is a positive integer).

  Furthermore, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that has been subjected to spatial frequency block encoding, and the OFDM symbol configuration unit uses an (N × M + 1) carrier according to a continuous pilot scheme. A pilot signal is arranged at a rate of once every (M is a positive integer).

  Further, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that has been subjected to spatial frequency block encoding, and the OFDM symbol configuration unit includes the data block including N pieces of data in a carrier direction. The pilot signals are arranged by a pilot symbol system so that M (M is a positive integer) are continuously allocated to the.

  Further, in the transmission apparatus according to the present invention, the block encoding unit generates the data block that has been subjected to spatial frequency block encoding, and the OFDM symbol configuration unit performs (N × M + 1) according to a scattered pilot scheme. The pilot signal is arranged so that the amount of shift in the carrier direction becomes 0 at a rate of once per carrier (M is a positive integer).

  In order to solve the above problem, a receiving apparatus according to the present invention is a receiving apparatus that receives data transmitted from the transmitting apparatus according to any one of claims 1 to 7, wherein the received OFDM signal is received. An OFDM demodulator that demodulates the data block according to the configuration of the OFDM symbol, and a block code decoder that decodes a data block from the demodulated OFDM signal.

  Moreover, in order to solve the said subject, the transmission program which concerns on this invention makes a computer function as one of the said transmission apparatuses.

  Moreover, in order to solve the said subject, the receiving program which concerns on this invention makes a computer function as said receiving apparatus.

  According to the present invention, it is possible to transmit and receive block-coded data without reducing transmission capacity and transmission path response estimation accuracy.

It is a figure which shows the OFDM symbol structure by the transmitter which concerns on 1st Embodiment. 2 is a flowchart showing a method of configuring the OFDM symbol of FIG. It is a figure which shows the OFDM symbol structure by the transmitter which concerns on 2nd Embodiment. 4 is a flowchart illustrating a method for configuring the OFDM symbol of FIG. 3. It is a figure which shows the OFDM symbol structure by the transmitter which concerns on 3rd Embodiment. 6 is a flowchart illustrating a method of configuring the OFDM symbol of FIG. It is a figure which shows the OFDM symbol structure by the transmitter which concerns on 4th Embodiment. It is a flowchart which shows the structure method of the OFDM symbol of FIG. It is a figure which shows the OFDM symbol structure by the transmitter which concerns on 5th Embodiment. 10 is a flowchart illustrating a method of configuring the OFDM symbol of FIG. It is a figure which shows the OFDM symbol structure by the transmitter which concerns on 6th Embodiment. 12 is a flowchart illustrating a method of configuring the OFDM symbol of FIG. It is a functional block diagram which shows the structure of the principal part of the transmitter which concerns on 7th Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM modulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the transmitter which concerns on 8th Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM modulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the transmitter which concerns on 9th Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM modulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the receiver which concerns on 10th Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM demodulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the receiver which concerns on 11th Embodiment. It is a functional block diagram which shows the structure of the principal part of the OFDM demodulation part of FIG. It is a functional block diagram which shows the structure of the principal part of the receiver which concerns on 12th Embodiment. FIG. 24 is a functional block diagram illustrating a configuration of a main part of the OFDM demodulation unit in FIG. 23. It is a block diagram which shows the OFDM transmission system which performs 2x2 MIMO transmission. It is a figure which shows arrangement | positioning of the pilot pattern in the case of FIG. It is a block diagram which shows the OFDM transmission system which performs 4x4 MIMO transmission. It is a figure which shows arrangement | positioning of the pilot pattern in the case of FIG. It is a figure which shows arrangement | positioning of the pilot signal of CP system. It is a figure which shows arrangement | positioning of the pilot signal of a pilot symbol system. It is a figure which shows arrangement | positioning of the pilot signal of SP system. It is a figure which shows data allocation in the case of transmitting the space-time block coding data with two transmission antennas.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the symbol configuration of the OFDM signal by the transmission apparatus according to the present invention will be described. In the following description, a symbol located at a symbol number or carrier number to which data is assigned is referred to as a data carrier symbol. For convenience of explanation, the number of data N (N is a positive integer equal to or greater than 2) that is treated as one block in block coding is N = 2. In the case of N = 2, Alamouti space-time block coding of equation (1) can be used. Further, in the configuration diagram of the OFDM symbol shown below, the pilot signal is indicated by hatching, the data is indicated by white, and the data block is indicated by a thick frame.

  First, as a first embodiment to a third embodiment, an OFDM symbol configuration in the case of transmitting data block-coded in the time direction by space-time block coding will be described.

(First embodiment)
FIG. 1 is a diagram showing an OFDM symbol configuration by the transmission apparatus according to the first embodiment of the present invention. The transmitting apparatus according to the present embodiment performs space-time block coding with two data carrier symbols and transmits data by the CP scheme. In the CP method, data carrier symbols are arranged in the symbol direction. Therefore, in the present embodiment, as shown in FIG. 1, a plurality of data blocks are arranged side by side with the number of symbols as a plurality of periods of the data blocks. FIG. 1 illustrates an example in which an integer number of data blocks are arranged in one carrier.

  FIG. 2 is a flowchart showing an OFDM symbol configuration method according to the first embodiment. First, the number N of data constituting the data block is determined (step S21). In the case of FIG. 1, N = 2. Next, the number M of data blocks to be continuously arranged in the time direction (M is a positive integer) is determined (step S22). Thereafter, when pilot carrier number Z is determined (step S23), M data blocks are arranged in the symbol direction except for Z (step S24).

  According to the present embodiment, the number of OFDM symbols constituting one period of the OFDM signal is N × M, and the data constituting each data block is continuous in the time direction. The pilot signal is assigned to a specific pilot carrier number Z by the CP method. Therefore, the transmitting device can transmit data without causing a reduction in transmission capacity, and the receiving device can demodulate received data without causing a reduction in estimation accuracy of the transmission path response.

(Second Embodiment)
FIG. 3 is a diagram illustrating an OFDM symbol configuration by the transmission apparatus according to the second embodiment of the present invention. The transmission apparatus according to the present embodiment performs space-time block coding with two data carrier symbols and transmits data by a pilot symbol scheme. In the pilot symbol scheme, pilot signals are arranged continuously in a carrier direction at specific symbols. Therefore, in this embodiment, as shown in FIG. 3, pilot symbols are arranged at a rate of once per (N × M + 1) symbols, and data blocks are arranged side by side in the symbol direction. FIG. 3 illustrates the case where N = 2 and M = 2.

  FIG. 4 is a flowchart showing an OFDM symbol configuration method according to the second embodiment. First, the number N of data constituting the data block is determined (step S41). In the case of FIG. 3, N = 2. Next, the number M of data blocks to be continuously arranged in the time direction is determined (step S42). In the case of FIG. 3, M = 2. After that, when the pilot symbol number Z is determined at a cycle of (N × M + 1) (step S43), M data blocks are arranged side by side in the symbol direction except Z (step S44).

  According to the present embodiment, pilot symbols are arranged once per (N × M + 1) symbols, and the data constituting each data block is continuous in the time direction. Therefore, by appropriately setting the number M of data blocks to be arranged between pilot symbols, data is transmitted without causing a reduction in data transmission capacity by the transmission device and a decrease in estimation accuracy of the transmission path response in the reception device. be able to.

(Third embodiment)
FIG. 5 is a diagram illustrating an OFDM symbol configuration by the transmission apparatus according to the third embodiment of the present invention. The transmission apparatus according to the present embodiment performs space-time block coding with two data carrier symbols and transmits data by the SP method. In the SP method, pilot signals are distributed and arranged on specific carriers and symbols. Therefore, in the present embodiment, as shown in FIG. 5, for a certain carrier, scattered pilots are arranged at a rate of once per (N × M + 1) symbols. Further, when the position of the scattered pilot in the carrier is x and the shift amount in the symbol direction is y and the shift amount in the carrier direction is y, the scattered pilot is assigned to each position shifted by x = 0 and y = 3. Deploy. FIG. 5 shows a case where scattered pilots are arranged at symbol numbers 1 and 6 for a carrier number (3k + 1) (k is 0 and a positive integer), where N = 2, M = 2, and the number of symbols is 10. Illustrated.

  FIG. 6 is a flowchart showing an OFDM symbol configuration method according to the third embodiment. First, the number N of data constituting the data block is determined (step S61). In the case of FIG. 5, N = 2. Next, the number M of data blocks to be continuously arranged in the time direction is determined (step S62). In the case of FIG. 5, M = 2. Thereafter, the symbol number Z in which the scattered pilot is arranged for a certain carrier is determined at (N × M + 1) cycles (step S63). Next, the scattered pilot position determined at step S63 is determined as the scattered pilot position every time x = 0 in the symbol direction and y-shifted in the carrier direction (step S64). Thereafter, M data blocks are arranged in the symbol direction except for the scattered pilot position (step S65).

  According to the present embodiment, each data block can be continuously arranged in the time direction for each carrier. In addition, a larger number of data blocks can be arranged for a carrier to which a scattered pilot is not allocated. Therefore, the transmission apparatus can improve the data transmission capacity, and the reception apparatus can demodulate the reception data without degrading the estimation accuracy of the transmission path response.

  Next, as the fourth to sixth embodiments, data subjected to space frequency block coding (SFBC) is transmitted using the Alamouti space-time block code of Equation (1). An OFDM symbol configuration in this case will be described. In SFBC, a data block is configured by combining data carrier symbols in the carrier direction.

(Fourth embodiment)
FIG. 7 is a diagram illustrating an OFDM symbol configuration by a transmission apparatus according to the fourth embodiment of the present invention. The transmitting apparatus according to the present embodiment performs spatial frequency block coding with two data carrier symbols and transmits data by the CP method. In the CP method, data carrier symbols are arranged in the symbol direction. Therefore, in this embodiment, as shown in FIG. 7, pilot signals are arranged at a rate of once per (N × M + 1) carrier. FIG. 7 illustrates a case where N = 2 and M = 4.

  FIG. 8 is a flowchart showing an OFDM symbol configuration method according to the fourth embodiment. First, the number N of data constituting the data block is determined (step S81). In the case of FIG. 7, N = 2. Next, the number M of data blocks continuously arranged in the carrier direction is determined (step S82). In the case of FIG. 7, M = 4. After that, when the pilot carrier number Z is determined at a cycle of (N × M + 1) (step S83), M data blocks are arranged side by side in the carrier direction except Z (step S84).

  According to the present embodiment, pilot signals are arranged at a rate of once per (N × M + 1) carrier, and data constituting each data block is continuous in the carrier direction. Therefore, by appropriately setting the number M of data blocks arranged between pilot signals, data is transmitted without causing a reduction in data transmission capacity by the transmission device and a decrease in estimation accuracy of the transmission path response in the reception device. be able to.

(Fifth embodiment)
FIG. 9 is a diagram showing an OFDM symbol configuration by the transmission apparatus according to the fifth embodiment of the present invention. The transmitting apparatus according to the present embodiment performs spatial frequency block coding with two data carrier symbols and transmits data by a pilot symbol scheme. In the pilot symbol scheme, pilot signals are arranged continuously in a carrier direction at specific symbols. Therefore, in this embodiment, as shown in FIG. 9, a plurality of data blocks are arranged in the carrier direction with the number of carriers being a plurality of periods of the data block. FIG. 9 illustrates the case where N = 2.

  FIG. 10 is a flowchart showing an OFDM symbol configuration method according to the fifth embodiment. First, the number N of data constituting the data block is determined (step S101). In the case of FIG. 9, N = 2. Next, the number M of data blocks continuously arranged in the carrier direction is determined (step S102). Thereafter, when the pilot symbol number Z is determined (step S103), M data blocks are arranged in the carrier direction excluding Z (step S104).

  According to the present embodiment, the number of carriers constituting one period of the OFDM signal is N × M, and the data constituting each data block is continuous in the carrier direction. A pilot signal is assigned to a specific pilot symbol number Z by a pilot symbol scheme. Therefore, the transmitting device can transmit data without causing a reduction in transmission capacity, and the receiving device can demodulate received data without causing a reduction in estimation accuracy of the transmission path response.

(Sixth embodiment)
FIG. 11 is a diagram illustrating an OFDM symbol configuration by the transmission apparatus according to the sixth embodiment of the present invention. The transmission apparatus according to the present embodiment performs spatial frequency block coding with two data carrier symbols and transmits data by the SP method. In the SP method, pilot signals are distributed and arranged on specific carriers and symbols. Therefore, in the present embodiment, as shown in FIG. 11, for a certain symbol, scattered pilots are arranged at a rate of once per (N × M + 1) carrier. Further, when the scattered pilot position in the symbol is x and the shift amount in the symbol direction is y and the shift amount in the carrier direction is y, a scattered pilot is assigned to each position shifted by x = 2 and y = 0. Deploy. FIG. 11 exemplifies a case where scattered pilots are arranged in carrier numbers 1 and 16 for symbol number (2k + 1) (k is 0 and a positive integer), where N = 2 and M = 7.

  FIG. 12 is a flowchart showing an OFDM symbol configuration method according to the sixth embodiment. First, the number N of data constituting the data block is determined (step S121). In the case of FIG. 11, N = 2. Next, the number M of data blocks to be continuously arranged in the carrier direction is determined (step S122). In the case of FIG. 11, M = 7. Thereafter, the carrier number Z in which the scattered pilot is arranged for a certain symbol is determined at (N × M + 1) cycles (step S123). Next, the scattered pilot position determined in step S123 is determined as the scattered pilot position every time x = 0 in the symbol direction and y = 0 in the carrier direction (step S124). Thereafter, M data blocks are arranged in the carrier direction except for the scattered pilot position (step S125).

  According to the present embodiment, each data block can be continuously arranged in the carrier direction for each symbol. In addition, a larger number of data blocks can be arranged for symbols to which no scattered pilot is assigned. Therefore, the transmission apparatus can improve the data transmission capacity, and the reception apparatus can demodulate the reception data without degrading the estimation accuracy of the transmission path response.

  Next, embodiments of the transmission apparatus described in the above-described embodiments and the reception apparatus that receives data transmitted from the transmission apparatus will be described. In the following embodiments, a description will be given of a transmission apparatus when the number of transmission antennas is one, two, and four and a reception apparatus when the number of reception antennas is one, two, and four. The number of transmitting / receiving antennas is not limited to these. These transmitters and receivers are determined in combination according to SISO (Single Input Single Output), SIMO (Single Input Multiple Output), MISO (Multiple Input Single Output), and MIMO transmission form. For example, when space-time block coding or space-frequency block coding is performed using an Alamouti code, the number of transmission antennas is generally a transmission apparatus with two transmission antennas. In addition, the STBC code by H. Jafarkahni (see, for example, “Aquasi-orthogonal space-time block code”, IEEE Transactions on Communications, vol49, no.1, pp.1-4, Jan 2001) is used. In the case of performing block coding or spatial frequency block coding, in general, the number of transmission antennas is four.

  First, as the seventh to ninth embodiments, transmission apparatuses having one, two, and four transmission antennas will be described.

(Seventh embodiment)
FIG. 13 is a functional block diagram showing the configuration of the main part of the transmitting apparatus according to the seventh embodiment of the present invention. Transmitting apparatus 100 according to the present embodiment transmits an OFDM signal from one transmission antenna 110, and includes error correction coding section 120, carrier modulation section 130, block coding section 140, OFDM modulation section 150, RF (Radio Frequency) unit 160 is provided.

  The transmission signal (bit stream) input to the transmission apparatus 100 is error correction encoded by the error correction encoding unit 120 and input to the carrier modulation unit 130. For example, the error correction encoding unit 120 uses a BCH (Bose Chaudhuri Hocquenghem) code as an outer code and an LDPC (Low Density Parity Check) code as an inner code, and performs error correction encoding on the transmission signal.

  Carrier modulation section 130 maps the error correction encoded transmission signal to the IQ plane according to a predetermined modulation scheme for each carrier (subcarrier), and outputs the result to block encoding section 140.

  The block coding unit 140 performs space-time block coding or space frequency block coding on the transmission signal input from the carrier modulation unit 130 for each carrier using, for example, an Alamouti code, and outputs the result to the OFDM modulation unit 150.

  The OFDM modulation unit 150 generates an OFDM signal from the data block input from the block coding 140 and outputs the OFDM signal to the RF unit 160.

  FIG. 14 is a functional block diagram illustrating a configuration of a main part of the OFDM modulation unit 150. The OFDM modulation unit 150 includes a pilot signal generation unit 151, an OFDM symbol configuration unit 152, an IFFT (Inverse Fast Fourier Transform) unit 153, a GI (Guard Interval) addition unit 154, an orthogonal modulation unit 155, and a D / A (Digital / Analog). A conversion unit 156 is provided.

  Pilot signal generation section 151 generates a pilot signal having a predetermined amplitude and phase and outputs the pilot signal to OFDM symbol configuration section 152.

  The OFDM symbol configuration section 152 performs pilot for the data block input from the block encoding section 140 of FIG. 13 according to the OFDM symbol configuration of any one of the first to sixth embodiments. An OFDM symbol is generated by inserting a pilot signal input from signal generation section 150 and output to IFFT section 153. In the present embodiment, since one transmission antenna 110 is used, for example, when the input data block is two data blocks obtained by space-time block coding obtained from Equation (1), one OFDM is used. In the symbol configuration, two data blocks are continuously arranged in the symbol direction on the same carrier number, or two data blocks are arranged side by side on the same symbol number in which adjacent carrier numbers are continuous. In addition, in the case where the spatial frequency block encoding is obtained using the equation (1), two data blocks are continuously arranged in the carrier direction at the same symbol number in one OFDM symbol configuration. Alternatively, two data blocks are arranged side by side on the same carrier number with consecutive symbol numbers. Alternatively, two data blocks are sequentially arranged in the same carrier number and the same symbol number in a sequential OFDM symbol configuration, that is, in a sequential frame, according to space-time block coding or space-frequency block coding.

  IFFT section 153 performs an IFFT (Inverse Fast Fourier Transform) process on the OFDM symbol input from OFDM symbol configuration section 152 to generate a time-domain effective symbol signal, and outputs it to GI adding section 154.

  The GI adding unit 154 inserts a guard interval obtained by copying the latter half of the effective symbol signal at the head of the effective symbol signal input from the IFFT unit 153 and outputs the guard interval to the orthogonal modulation unit 155. The guard interval is inserted in order to reduce intersymbol interference when receiving an OFDM signal, and is set so that the delay time of the multipath delay wave does not exceed the guard interval length.

  Orthogonal modulation section 155 performs orthogonal modulation processing on the baseband signal input from GI addition section 154 to generate an OFDM signal, and outputs the OFDM signal to D / A conversion section 156.

  The D / A conversion unit 156 converts the OFDM signal input from the quadrature modulation unit 155 into an analog signal and outputs the analog signal to the RF unit 160 in FIG.

  The RF unit 160 converts the OFDM signal input from the OFDM modulation unit 150 into a predetermined radio frequency band and radiates it from the transmission antenna 110.

(Eighth embodiment)
FIG. 15 is a functional block diagram showing the configuration of the main part of the transmitting apparatus according to the eighth embodiment of the present invention. Transmitting apparatus 101 according to the present embodiment transmits a plurality of OFDM signals in the same frequency band from two transmitting antennas 110-1 and 110-2. Therefore, the transmission apparatus 101 includes two RF units 160-1 and 160-2 corresponding to the two transmission antennas 110-1 and 110-2 in the configuration of the transmission apparatus 100 illustrated in FIG.

  Further, as shown in FIG. 16, the OFDM modulation unit 150 includes two IFFT units 153-1 and 153-2 and two GI addition units 154 corresponding to the two transmission antennas 110-1 and 110-2. 1, 154-2, two orthogonal modulation units 155-1 and 155-2, and two D / A conversion units 156-1 and 156-2.

  The OFDM symbol configuration unit 152 performs a pilot signal generation unit on the data block input from the block coding unit 140 according to the OFDM symbol configuration of any one of the first to sixth embodiments. A pilot signal input from 151 is inserted to generate two systems of OFDM symbols corresponding to the two transmission antennas 110-1 and 110-2. In the present embodiment, since two transmission antennas 110-1 and 110-2 are used, an input data block is, for example, two data blocks obtained by space-time block coding obtained from Equation (1). In this case, two data blocks are distributed for each transmission antenna, and arranged in the same symbol number with the same carrier number in each OFDM symbol configuration. In addition, in the case of the spatial frequency block coding obtained using Equation (1), two data blocks are distributed for each transmission antenna, and in each OFDM symbol configuration, the same symbol number is consecutive. To the carrier number.

  In the OFDM symbol configuration section 152, the OFDM symbol configured for each transmission antenna includes the corresponding IFFT sections 153-1 and 153-2, GI addition sections 154-1 and 154-2, and orthogonal modulation sections 155-1 and 155-. 2, radiated from the two transmission antennas 110-1 and 110-2 as radio waves in a predetermined radio frequency band through the D / A conversion units 156-1 and 156-2 and the RF units 160-1 and 160-2. The Other configurations are the same as those of the transmission device 100 shown in FIG.

(Ninth embodiment)
FIG. 17 is a functional block diagram showing the configuration of the main part of the transmitting apparatus according to the ninth embodiment of the present invention. Transmitting apparatus 102 according to the present embodiment transmits a plurality of OFDM signals in the same frequency band from four transmission antennas 110-1 to 110-4. Therefore, the transmission apparatus 102 includes four RF units 160-1 to 160-4 corresponding to the four transmission antennas 110-1 to 110-4 in the configuration of the transmission apparatus 100 illustrated in FIG.

  Also, as shown in FIG. 18, the OFDM modulation unit 150 includes four IFFT units 153-1 to 153-4 and four GI addition units 154 corresponding to the four transmission antennas 110-1 to 110-4. 1 to 154-4, four orthogonal modulation units 155-1 to 155-4, and four D / A conversion units 156-1 to 156-4.

  The OFDM symbol configuration unit 152 performs a pilot signal generation unit on the data block input from the block coding unit 140 according to the OFDM symbol configuration of any one of the first to sixth embodiments. The pilot signal input from 151 is inserted to generate four systems of OFDM symbols corresponding to the four transmission antennas 110-1 to 110-4. In the present embodiment, since four transmission antennas 110-1 to 110-4 are used, when the input data block is, for example, the STBC code by H. Jafarkahni described above, the data block is assigned to each transmission antenna. In each OFDM symbol configuration, the same carrier number and the same symbol number are continuously arranged according to space-time block coding or space-frequency block coding.

  In the OFDM symbol configuration section 152, the OFDM symbol configured for each transmission antenna includes the corresponding IFFT sections 153-1 to 153-4, GI addition sections 154-1 to 154-4, and orthogonal modulation sections 155-1 to 155-. 4. After passing through the D / A conversion units 156-1 to 156-4 and the RF units 160-1 to 160-4, they are radiated from the four transmission antennas 110-1 to 110-4 as radio waves in a predetermined radio frequency band. The Other configurations are the same as those of the transmission device 100 shown in FIG.

  According to transmitting apparatuses 100 to 102 according to the seventh embodiment to the ninth embodiment, in OFDM symbol configuration section 152 of OFDM modulation section 150, the OFDM symbol according to any one of the first to sixth embodiments. According to the configuration, the data blocks are continuously arranged in the symbol direction or the carrier direction, so that the block-coded data can be obtained with a simple configuration without reducing the transmission capacity and the accuracy of estimating the transmission path response. It becomes possible to transmit.

  In addition, the transmission apparatuses 100 to 102 described above can also function using a computer. In this case, the computer stores a transmission program that describes the processing contents for realizing each function of the transmission device in the storage unit of the computer, and reads and executes the transmission program by the CPU of the computer. A transmission device can be realized.

  Next, as tenth to twelfth embodiments, a description will be given of receivers having one, two, and four reception antennas.

(Tenth embodiment)
FIG. 19 is a functional block diagram showing the configuration of the main part of the receiving apparatus according to the tenth embodiment of the present invention. Receiving apparatus 200 according to the present embodiment receives an OFDM signal using one receiving antenna 210, and includes RF section 220, OFDM demodulating section 230, block code decoding section 240, carrier demodulating section 250, error correction. A code decoding unit 260 is provided.

  The RF unit 220 converts an OFDM signal in a predetermined radio frequency band from a received signal received by the receiving antenna 210 into an OFDM signal having a specified frequency and a specified level, and outputs the OFDM signal to the OFDM demodulator 230.

  FIG. 20 is a functional block diagram illustrating a configuration of a main part of the OFDM demodulator 230. The OFDM demodulation unit 230 includes an A / D conversion unit 231, an orthogonal demodulation unit 232, a GI removal unit 233, an FFT (Fast Fourier Transform) unit 234, a pilot signal extraction unit 235, and a transmission path response estimation unit 236.

  The A / D conversion unit 231 converts the analog signal input from the RF unit 220 into a digital signal and outputs the digital signal to the quadrature demodulation unit 232.

  The quadrature demodulation unit 232 performs quadrature demodulation on the signal input from the A / D conversion unit 231 to generate a baseband signal and outputs the baseband signal to the GI removal unit 233.

  The GI removal unit 233 removes the guard interval from the baseband signal input from the quadrature demodulation unit 232 and extracts an effective symbol signal, and outputs it to the FFT unit 234.

  The FFT unit 234 performs FFT processing on the effective symbol signal input from the GI removal unit 233 to generate a complex baseband signal in the frequency domain. This complex baseband signal is output to pilot signal extraction section 235 and also output to block code decoding section 240 in FIG.

  Pilot signal extraction section 235 extracts a pilot signal from the complex baseband signal input from FFT section 234 according to the OFDM symbol configuration of any one of the first to sixth embodiments determined in advance. It outputs to the transmission path response estimation part 236.

  Transmission path response estimation section 236 estimates the transmission path response using the pilot signal extracted by pilot signal extraction section 235, and outputs the result to block code decoding section 240 in FIG.

  In FIG. 19, block code decoding section 240 decodes the block code based on the complex baseband signal and transmission path response estimation result input from OFDM demodulation section 230 and outputs the decoding result to carrier demodulation section 250. . The output decoding result varies depending on the combination of the block code and the error correction code, and is a complex baseband signal, LLR (Log Likelihood Ratio), or the like.

  Carrier demodulation section 250 demodulates each subcarrier using the decoding result input from block code decoding section 240, and outputs IQ data, LLR, and the like to error correction code decoding section 260.

  Error correction code decoding section 260 decodes the error correction code using values such as IQ data and LLR input from carrier demodulation section 250, and outputs a bit stream.

(Eleventh embodiment)
FIG. 21 is a functional block diagram showing the configuration of the main part of the receiving apparatus according to the eleventh embodiment of the present invention. Receiving apparatus 201 according to the present embodiment receives OFDM signals using two receiving antennas 210-1 and 210-2. Therefore, the receiving apparatus 201 includes two RF units 220-1 and 220-2 corresponding to the two receiving antennas 210-1 and 210-2 in the configuration of the receiving apparatus 200 illustrated in FIG.

  Further, as shown in FIG. 22, the OFDM demodulator 230 includes two A / D converters 231-1 and 231-2 and two orthogonal demodulators corresponding to the two reception antennas 210-1 and 210-2. Units 232-1 and 232-2, two GI removal units 233-1 and 233-2, two FFT units 234-1 and 234-2, two pilot signal extraction units 235-1 and 235-2, two Transmission path response estimation units 236-1 and 236-2 are provided.

  The OFDM demodulator 230 generates each complex baseband signal from the input signal for each receiving antenna in the same manner as in the tenth embodiment, and also determines the first through sixth embodiments. A pilot signal is extracted according to any OFDM symbol configuration in the form of (1) to estimate the transmission line response. The estimation results of the complex baseband signal and the transmission path response for each reception antenna are input to the block code decoding unit 240, and the block code is decoded. Using the decoding result of the decoded block code, carrier demodulation section 250 calculates IQ data, LLR, etc. for each subcarrier, error correction code decoding section 260 decodes the error correction code, and outputs a bit stream .

(Twelfth embodiment)
FIG. 23 is a functional block diagram showing the configuration of the main part of the receiving apparatus according to the twelfth embodiment of the present invention. Receiving apparatus 202 according to the present embodiment receives OFDM signals using four receiving antennas 210-1 to 210-4. Therefore, the receiving apparatus 202 includes four RF units 220-1 to 220-4 corresponding to the four receiving antennas 210-1 to 210-4 in the configuration of the receiving apparatus 200 illustrated in FIG.

  Further, as shown in FIG. 24, the OFDM demodulator 230 includes four A / D converters 231-1 to 231-4 and four orthogonal demodulations corresponding to the four reception antennas 210-1 to 210-4. Sections 232-1 to 232-4, four GI removal sections 233-1 to 233-4, four FFT sections 234-1 to 234-4, four pilot signal extraction sections 235-1 to 235-4, and four Transmission path response estimation units 236-1 to 236-4 are provided.

  Similarly to the case of the eleventh embodiment, the OFDM demodulator 230 generates each complex baseband signal from the input signal for each reception antenna, and also performs predetermined first to sixth embodiments. A pilot signal is extracted according to any OFDM symbol configuration in the form to estimate the transmission line response. As in the case of the eleventh embodiment, the estimation results of the complex baseband signal and the transmission path response for each reception antenna are input to the block code decoding unit 240, and the block code is decoded. Then, using the decoding result of the decoded block code, the carrier demodulation unit 250 calculates IQ data, LLR, etc. for each subcarrier, the error correction code decoding unit 260 decodes the error correction code, and the bit stream is Output.

  According to the receiving apparatuses 200 to 202 according to the tenth to twelfth embodiments, the transmitting apparatus according to any one of the seventh to ninth embodiments can be used in the first to sixth embodiments. Since a signal transmitted according to any OFDM symbol in the form is received and decoded, high-accuracy decoding is possible with a simple configuration.

  Note that the above-described receiving apparatuses 200 to 202 can also function using a computer. In this case, the computer stores the reception program describing the processing contents for realizing each function of the reception device in the storage unit of the computer, and reads and executes the reception program by the CPU of the computer, A receiving device can be realized.

  Although the above-described embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims.

  As described above, according to the present invention, block-encoded data is transmitted using a plurality of OFDM signals in the same frequency band without causing a reduction in transmission capacity and a reduction in estimation accuracy of a transmission path response. Therefore, it is useful for a transmission device and a reception device in an OFDM transmission system.

100, 101, 102 Transmitting apparatus 110, 110-1 to 110-4 Transmitting antenna 120 Error correction encoding unit 130 Carrier modulation unit 140 Block encoding unit 150 OFDM modulation unit 151 Pilot signal generation unit 152 OFDM symbol configuration unit 153, 153 -1 to 153-4 IFFT unit 154, 154-1 to 154-4 GI adding unit 155, 155-1 to 155-4 orthogonal modulation unit 156, 156-1 to 156-4 D / A conversion unit 160, 160- 1-160-4 RF unit 200, 201, 202 Receiving device 210, 210-1 to 210-4 Receiving antenna 220, 220-1 to 220-4 RF unit 230 OFDM demodulator 231, 231-1 to 231-4 A / D converter 232, 232-1 to 232-4 Quadrature demodulator 233, 233-1 to 2 3-4 GI removal unit 234, 234-1 to 234-4 FFT unit 235, 235-1 to 235-4 Pilot signal extraction unit 236, 236-1 to 236-4 Transmission path response estimation unit 240 Block code decoding unit 250 Carrier demodulation unit 260 Error correction code decoding unit

Claims (10)

A transmission device that transmits data using an OFDM signal,
A block encoding unit that generates a data block including N (N is a positive integer of 2 or more) pieces of data;
A pilot signal generator for generating a pilot signal for channel response estimation;
An OFDM symbol configuration unit that configures an OFDM symbol of the OFDM signal by the data block and the pilot signal, and
The OFDM symbol component is
The transmitting apparatus, wherein the pilot signal is arranged so that the data block is allocated to a data carrier symbol adjacent to the OFDM symbol. The block encoding unit generates the data block that is space-time block encoded,
The OFDM symbol configuration unit arranges the pilot signals by a continuous pilot scheme so that M (M is a positive integer) consecutive data blocks including N pieces of data are allocated in the symbol direction. The transmission device according to claim 1. The block encoding unit generates the data block that is space-time block encoded,
2. The transmission apparatus according to claim 1, wherein the OFDM symbol configuration section arranges a pilot signal at a rate of once per (N × M + 1) symbols (M is a positive integer) by a pilot symbol scheme. . The block encoding unit generates the data block that is space-time block encoded,
The OFDM symbol configuration unit uses a scattered pilot scheme to transmit a pilot signal so that the shift amount in the symbol direction becomes 0 at a rate of once per (N × M + 1) symbols (M is a positive integer). The transmitter according to claim 1, wherein the transmitter is arranged. The block encoding unit generates the data block subjected to spatial frequency block encoding,
2. The transmission according to claim 1, wherein the OFDM symbol configuration section arranges a pilot signal at a rate of once per (N × M + 1) carrier (M is a positive integer) by a continuous pilot scheme. apparatus. The block encoding unit generates the data block subjected to spatial frequency block encoding,
The OFDM symbol configuration unit arranges the pilot signal by a pilot symbol method so that M (M is a positive integer) consecutively allocated data blocks including N data in a carrier direction. The transmission device according to claim 1, wherein The block encoding unit generates the data block subjected to spatial frequency block encoding,
The OFDM symbol configuration unit uses a scattered pilot scheme to transmit a pilot signal so that the shift amount in the carrier direction becomes 0 at a rate of once per (N × M + 1) carriers (M is a positive integer). The transmitter according to claim 1, wherein the transmitter is arranged. A reception device that receives data transmitted from the transmission device according to any one of claims 1 to 7,
An OFDM demodulator for demodulating a received OFDM signal according to the structure of the OFDM symbol;
And a block code decoding unit that decodes a data block from the demodulated OFDM signal.   A transmission program for causing a computer to function as the transmission device according to any one of claims 1 to 7. A receiving program for causing a computer to function as the receiving device according to claim 8.

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