JPH1155211A - Bi-directional transmission system for ofdm signal and transmitting and receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize be-directional transmission by sending a transmission part of control data to a transmission side from a receiving side for receiving information data transmitting part sent from a transmission side in synchronism with an OFDM(orthogonal frequency division multiplexing) signal. SOLUTION: A video and sound to be transmitted is collected by a first transmitting and receiving device 5, and this is turned into an OFDM radio wave 3, and transmitted to a second to a second transmitting and receiving device 7, and the video and sound is reproduced. Also, a control signal inputted to the second transmitting and receiving device 7 is turned into an OFDM radio wave 4 in synchronism with the OFDM radio wave 3, and this is transmitted to the first transmitting and receiving device 5, and the control signal is demodulated, and the transmission parameter of the first transmitting and receiving device 5 is optimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a bidirectional transmission system of an OFDM signal suitable as a modulation system for digital television material broadcasting, digital television broadcasting, or digital audio broadcasting, and a transmission / reception apparatus.

[Summary of the Invention] [0002] The present invention relates to an Orthogonal Frequency Division Multiplex.
The present invention relates to a bi-directional transmission method of a ng: OFDM signal and a transmission / reception apparatus. The frequency band of the OFDM signal is transmitted by OFDM transmission of data such as video and audio (information data transmission unit), and control data is transmitted by OFDM. The control data transmission unit is frequency-divided into a transmission unit (control data transmission unit) and synchronized with the OFDM signal received at the reception point of the information data transmission unit, and the control data transmission unit is OFDM-transmitted in the reverse direction to thereby transmit the control data transmission unit. A method of controlling the transmission parameters of OFDM according to the control signal sent in the above, a method of using the control data transmission unit as a communication line to the transmission point,
A method of transmitting control data of a device at a transmission point according to a control signal transmitted by the control data transmission unit, a method of transmitting digital data such as video / audio information using the control data transmission unit, and the like are realized. Things.

[0003]

2. Description of the Related Art Various techniques for transmitting video data and audio data from a transmission point to a reception point using an OFDM signal have been developed.

[0004]

However, in such an OFDM signal transmission mode, the OFD signal is transmitted at the transmission point side.
Since the transmission parameters of the M signal are determined, this O
On the receiving point receiving the FDM signal, the transmission parameters on the transmitting point cannot be changed.

[0005] For this reason, depending on the severity of the transmission path,
Even when the strength of the error correction is changed, not only cannot the transmission point parameter be controlled from the receiving point side to the transmitting point side, but also the communication from the receiving point side to the transmitting point side or the receiving point side However, there is an inconvenience that it is not possible to perform device control on the transmission point side.

The present invention has been made in view of the above circumstances, and has been described in claims 1 and 2.
In the bidirectional transmission, the control data transmission unit is transmitted to the transmission point side in synchronization with the OFDM signal from the reception point that receives the information data transmission unit transmitted from the transmission point side so that the frequency bands are adjacent to each other. OFD that can realize
It is intended to provide a bidirectional transmission system for M signals.

According to a third aspect of the present invention, the control data is transmitted by the control data transmission unit which performs OFDM transmission in the reverse direction from the reception point side, and the transmission parameter on the transmission point side transmitting the information data transmission unit is changed. Accordingly, an object of the present invention is to provide a bidirectional transmission method of an OFDM signal that can optimize transmission parameters and the like according to a state of a transmission path.

According to a fourth aspect of the present invention, digital data such as video / audio information for program monitoring is transmitted by a control data transmission unit which performs OFDM transmission in a reverse direction from a receiving point side.
An object of the present invention is to provide an OFDM signal bidirectional transmission system in which various digital data can be transmitted from a receiving point to a transmitting point by causing the transmitting point transmitting the information data transmitting unit to receive the information. I have.

According to a fifth aspect of the present invention, the control data is transmitted by the control data transmission unit which performs OFDM transmission in the reverse direction from the reception point side, and the device at the transmission point side transmitting the information data transmission unit is controlled. Accordingly, an object of the present invention is to provide a bidirectional transmission method of an OFDM signal that can directly control a camera device or the like on a transmission point side and transmit desired video data or the like.

According to a sixth aspect of the present invention, the control data transmission unit which performs OFDM transmission from the reception point in the reverse direction forms a communication line between the reception point and the transmission point, thereby enabling transmission from the reception point. OFD that can issue various requests to the point side
It is intended to provide a bidirectional transmission system for M signals.

Further, according to the present invention, bidirectional transmission between a transmission point and a reception point can be realized, optimization of transmission parameters and the like according to the state of a transmission path, remote control of a transmission point side device, or It is an object of the present invention to provide a transmission / reception device capable of issuing various requests from a reception point to a transmission point.

[0012]

In order to achieve the above object, according to the present invention, a frequency band of an OFDM signal is defined by an information data transmission section for transmitting video data and audio data; It is frequency-divided into a control data transmission unit for transmission, and at the reception point of the information data transmission unit, the control data transmission unit performs OFDM transmission in the reverse direction toward the transmission point in synchronization with the received OFDM signal. It is characterized by:

According to a second aspect of the present invention, a channel having a fixed frequency bandwidth is frequency-divided into an information data transmitting section for transmitting video data and audio data and a control data transmitting section for transmitting control data. At the receiving point of the information data transmission unit, in synchronization with the received OFDM signal,
It is characterized in that the control data transmission unit performs OFDM transmission in the reverse direction toward the transmission point.

According to claim 3, claim 1 or 2
In the bidirectional transmission method of the OFDM signal described in the above, the control data transmission unit that performs OFDM transmission in the reverse direction from the receiving point side changes transmission parameters such as the type of error correction, the bit rate accompanying the error correction, and carrier modulation. The transmission data is transmitted from the information data transmission unit, and the transmission parameters are changed by the control data.

Further, in claim 4, claim 1 or 2
In the two-way transmission method of the OFDM signal described in the above, the control data transmission unit that performs OFDM transmission in the reverse direction from the receiving point side is configured by digital data such as video and audio information for program monitoring, and the information data transmission unit It is characterized in that the digital data is received on the transmitting point side that is transmitting.

According to claim 5, claim 1 or 2
In the bidirectional transmission method of the OFDM signal described in the above, the control data transmission unit that performs OFDM transmission in the reverse direction from the receiving point side is configured by control data for device control, the information data transmission unit by the control data, It is characterized by controlling the device at the transmitting point that is transmitting.

Further, in claim 6, claim 1 or 2
In the two-way transmission method of the OFDM signal described in the above, the control data transmission section that is OFDM-transmitted in the reverse direction from the receiving point side is constituted by digital data for a communication line, and the control data transmitting section communicates with the receiving point side. It is characterized by forming a communication line with the transmission point side.

According to a seventh aspect of the present invention, in order to realize the bidirectional transmission method of an OFDM signal according to any one of the first to sixth aspects, a transmission / reception device provided on a reception point side of the information data transmission unit. In synchronization with the received OFDM signal, control data for changing transmission parameters such as the type of error correction, accompanying bit rate, carrier modulation, digital data such as video / audio information for program monitoring, equipment A transmission device for performing OFDM transmission of a control data transmission unit having either control data for control or digital data for a communication line toward a transmission point of the information data transmission unit is provided. .

In the above structure, according to the first aspect, the OF
The frequency band of the DM signal is frequency-divided into an information data transmission section for transmitting video data and audio data, and a control data transmission section for transmitting control data, and the OFDM signal is received at the reception point of the information data transmission section. Synchronously, the control data transmission unit performs OFDM transmission in the reverse direction toward the transmission point, thereby realizing bidirectional transmission between the transmission point and the reception point.

According to a second aspect of the present invention, a channel having a fixed frequency bandwidth is frequency-divided into an information data transmission unit for transmitting video data and audio data, and a control data transmission unit for transmitting control data. The control data transmission unit performs OFDM transmission in the reverse direction toward the transmission point in synchronization with the OFDM signal received at the reception point of the information data transmission unit, thereby realizing bidirectional transmission between the transmission point and the reception point.

According to a third aspect of the present invention, the control data transmission unit which performs OFDM transmission in the reverse direction from the receiving point side,
By transmitting control data for changing the transmission parameters such as the type of error correction, the accompanying bit rate, and the modulation of the carrier, by changing the transmission parameters on the transmission point transmitting the information data transmission unit, The transmission parameters and the like are optimized according to the state of the transmission path.

According to a fourth aspect of the present invention, the control data transmission unit which performs OFDM transmission in the reverse direction from the receiving point side,
Digital data such as video / audio information for program monitoring is transmitted and transmitted to the transmission point transmitting the information data transmission unit, so that various video images for program monitoring are transmitted from the reception point to the transmission point. Digital data such as voice information can be transmitted. Here, as digital data, for example,
Moving picture data encoded by MPEG2, JPE
Still image data encoded by G, MUSICA
The control data transmission unit alone, such as audio data encoded by M or the like and encoded information data,
It refers to those that transmit voice, information, etc.

According to a fifth aspect of the present invention, the control data transmission unit which performs OFDM transmission in the reverse direction from the receiving point side,
A device such as a camera device at the transmission point is remotely controlled to transmit desired video data and the like.

According to a sixth aspect of the present invention, the control data transmission section that performs OFDM transmission from the receiving point in the reverse direction forms a communication line between the receiving point and the transmitting point, thereby providing a communication line between the receiving point and the transmitting point. Various requests can be issued to the transmission point side.

According to a seventh aspect of the present invention, in order to realize the bidirectional transmission method of an OFDM signal according to any one of the first to sixth aspects, a transmitting / receiving device provided on a receiving point side of an information data transmitting unit includes: In synchronization with the received OFDM signal, control data for changing transmission parameters such as the type of error correction, accompanying bit rate, carrier modulation, digital data such as video / audio information for program monitoring, and equipment control Since the control data transmission section containing either the control data or the digital data for the communication line is OFDM-transmitted toward the transmission point side of the information data transmission section, bidirectional transmission between the transmission point and the reception point is performed. By realizing transmission, optimization of transmission parameters etc. according to the state of the transmission path, direct remote control of the camera device etc. at the transmission point side and desired video To transmit the like over data, or it is possible such to be capable out various requirements to the transmission point side from the receiving point side.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> FIG. 1 is a block diagram showing a first embodiment of a transmitting / receiving system for realizing a bidirectional transmission method of an OFDM signal according to the present invention.

The transmission / reception system 1a shown in FIG.
At the point 2, video data and audio data are transmitted using the OFDM radio wave 3, while the OFDM radio wave 4 is transmitted.
Receiving the control signal transmitted using the first
A second transmitting / receiving device 5 provided at the second point 6 for receiving video data and audio data transmitted using the OFDM radio wave 3 and transmitting the control signal using the OFDM radio wave 4 And a transmission / reception device 7. The first transmission / reception device 5 collects video and audio to be transmitted, converts the collected video and audio into an OFDM radio wave 3, and transmits the OFDM radio wave 3 to the second transmission / reception device 7. The second transmission / reception device 7 reproduces the video and the audio, and transmits the control signal input to the second transmission / reception device 7 to an OFDM radio wave 4 synchronized with the OFDM radio wave 3.
And transmits it to the first transmitting / receiving device 5. First transmitting / receiving device 5
Then, the control signal is demodulated to optimize the transmission parameters of the first transmitting / receiving device 5. “Synchronization” here means O
So that the carriers of the FDM radio waves 3 and 4 are orthogonal,
Locking the information symbol length, guard interval length, symbol switching timing, transmission carrier frequency, etc. of the OFDM signal.

The first transmitting / receiving device 5 includes a television camera device 8 for capturing video of a subject to be transmitted and generating video data, and a microphone 9 for capturing voice of the subject and generating audio data. The audio data obtained by the microphone 9 and the video data obtained by the television camera device 8 are converted into transmission parameters set in advance or transmission parameters specified by a control signal from the second transmission / reception device 7. For example, the audio data and the video data are modulated using transmission parameters indicating a type of error correction, a bit rate associated therewith, a modulation method of a carrier, and the like.
A modulation device 10 for generating an IF signal for DM, and a transmission device 11 for converting the IF signal output from the modulation device 10 into an OFDM radio wave 3 and transmitting the OFDM radio wave 3 to the second transmitting / receiving device 7
A receiving device 12 that receives the OFDM radio wave 4 transmitted from the second transmitting / receiving device 7 and generates an IF signal;
A demodulation device 13 demodulates the IF signal output from the reception device 12 to reproduce a control signal, supplies the control signal to the modulation device 10, and optimizes transmission parameters and the like.

FIG. 3 shows an example of a frequency spectrum transmitting information data and control data. As shown in FIG. 3, an information data transmission unit 14 that performs OFDM transmission of data such as video and audio, and an
It is adjacent to the control data transmission unit 15, which is a part to be FDM. In order to transmit the control data transmission unit 15 adjacent to the information data transmission unit 14, the carriers modulating the information data and the control data need to be orthogonal. The first transmission / reception device 5 collects and modulates video and audio to be transmitted, and transmits the information and data to the information data transmission unit 14 shown in FIG.
Is generated and transmitted to the second transmission / reception device 7. Further, in synchronization with the OFDM radio wave 3, the OFDM radio wave 4 composed of the control data transmission unit 15 transmitted from the second transmission / reception device 7 is received, and based on a control signal obtained by demodulating the OFDM radio wave 4, Modulation device 10
To optimize the transmission parameters.

The second transmitting / receiving device 7 receives the OFDM radio wave 3 transmitted from the first transmitting / receiving device 5,
A receiving device 16 for generating a signal, a demodulating device 17 for demodulating an IF signal output from the receiving device 16 to reproduce video data and audio data, and a demodulating operation of the demodulating device 17 for demodulating an input control signal. And a transmitting device 19 that converts the IF signal output from the modulating device 18 into an OFDM radio wave 4 and transmits the OFDM radio wave 4 to the first transmitting / receiving device 5 side. ing.

In this case, as shown in FIG. 2, the demodulator 17 performs quadrature detection of the IF signal output from the receiver 16 and then performs low-pass filtering and A / D conversion to perform I-axis data and A quadrature detector 20 for generating Q-axis data, and a timing signal generator for generating a symbol synchronization signal and a reproduced clock signal based on the I-axis data and Q-axis data output from the quadrature detector 20 21, I-axis side data output from the quadrature detector 20 based on the symbol synchronization signal output from the timing signal generator 21 and the reproduced clock signal,
And FFT processing and differential processing of the Q-axis data and the video data and audio data are reproduced,
A video / audio reproduction unit that generates a phase error signal; and a quadrature clock generation unit that generates a quadrature detection clock signal and a quadrature modulation clock signal based on the phase error signal output from the video / audio reproduction unit. ing.
The demodulation device 17 generates a symbol synchronization signal, a reproduction clock signal, a quadrature detection clock signal, and a quadrature modulation clock signal based on the IF signal output from the reception device 16, and generates a symbol The video data and the audio data included in the IF signal are reproduced by performing detection processing, low-pass filtering processing, A / D conversion processing, FFT processing, and differential processing.

The quadrature clock generator 23 oscillates at a preset frequency while increasing or decreasing the oscillation frequency in accordance with the phase error signal output from the video / audio reproducer 22 to generate a quadrature clock signal. A circuit 24 is provided, and supplies the generated quadrature clock signal to the quadrature detection unit 20 as a quadrature detection clock signal and to the modulation device 18 as a quadrature modulation clock signal.

The quadrature detection unit 20 includes the quadrature clock generation unit 2
3 and the receiving device 16
Multiplication circuit 25 that generates an I-axis side signal by multiplying by an IF signal output from a / 2 circuit, and a π / 2 circuit 26 that shifts the phase of the quadrature detection clock signal output from the quadrature clock generation unit 23 by π / 2. And a multiplication circuit 27 that multiplies the quadrature detection clock signal output from the π / 2 circuit 26 and shifted in phase by π / 2 with the IF signal output from the receiver 16 to generate a Q-axis side signal And each multiplication circuit 2
Two LPF circuits 2 for low-pass filtering the I-axis side signal and the Q-axis side signal output from 5, 27, respectively.
A / D conversion is performed on the low-pass filtered I-axis signal and Q-axis signal output from each of the LPF circuits 28 and 29 based on the reproduced clock signals output from the timing signal generation unit 21 and the clock signals 8 and 29, respectively. And two A / D conversion circuits 30 and 31 that generate I-axis side data and Q-axis side data and supply them to a timing signal generation unit 21 and a video / audio reproduction unit 22.

The timing signal generator 21 generates the symbol synchronization signal based on the I-axis data and the Q-axis data output from the quadrature detector 20.
2 and a variable frequency transmission circuit 33 that oscillates at a preset frequency and increases or decreases the oscillation frequency based on a symbol synchronization signal output from the synchronization reproduction circuit 32 to generate a reproduction clock signal. A symbol synchronization signal is generated based on the I-axis data and the Q-axis data output from the quadrature detection unit 20, and is supplied to the video / audio reproduction unit 22 and the modulation device 18. A reproduction clock signal is generated based on the synchronization signal, and supplied to each of the A / D conversion circuits 30, 31, the video / audio reproduction unit 22, and the modulation device 18.

The video / audio reproduction unit 22 converts the I-axis data and the Q-axis data output from the quadrature detection unit 20 into an FFT (high speed) based on the symbol synchronization signal and the reproduction clock signal output from the timing signal generation unit 21. Fourier transform) processing to reproduce an I-axis baseband signal and a Q-axis baseband signal, and an FFT circuit based on a reproduced clock signal output from the timing signal generator 21.
By taking a difference between the I-axis baseband signal and the Q-axis baseband signal output from the circuit 34 and the I-axis baseband signal and the Q-axis baseband signal of the immediately preceding symbol, the image is obtained. A differential circuit 35 for reproducing data and audio data, and a phase difference between phase data output from the differential circuit 35 and phase data originally output from the differential circuit 35 is detected. A phase error detection circuit 36 that generates a phase error signal and supplies the generated signal to the quadrature clock generator 23.

Further, as shown in FIG. 2, the modulation device 18 converts the input control signal into a mapping process, an IFFT process, and a guard synchronization signal based on the symbol synchronization signal and the reproduced clock signal output from the timing signal generation unit 21. A control signal modulating unit 37 that generates an I-axis signal and a Q-axis signal by performing an insertion process, and an I-axis output from the control signal modulating unit 37 based on the reproduced clock signal output from the timing signal generating unit 21 Side signal, Q axis side signal, D / A conversion processing,
Low-pass filtering processing, orthogonal transformation processing, IF
A quadrature modulation unit 38 that generates a signal and supplies the signal to the transmission device 19. Then, the OFDM radio wave 4 synchronized with the OFDM radio wave 3 (the information data transmission unit 14 shown in FIG. 3) transmitted from the first transmitting / receiving device 5 from the transmitting device 19, that is, each carrier of the OFDM radio wave 3, 4 The OFDM radio wave 4 composed of the control data transmission unit 15 in which the information symbol length, guard interval length, symbol switching timing, transmission carrier frequency, and the like are locked so as to be orthogonal to each other is transmitted.

The control signal modulating unit 37 is based on the reproduced clock signal output from the timing signal generating unit 21 and maps the input control signal to each carrier. An IFFT circuit 40 for performing IFFT conversion of data for each carrier output from the carrier mapping circuit 39 based on a symbol synchronization signal and a reproduced clock signal to generate I-axis data and Q-axis data; A guard synchronization insertion circuit 41 that inserts a guard interval into the I-axis data and the Q-axis data output from the IFFT circuit 40 based on the reproduced clock signal output from the section 21 and supplies the data to the quadrature modulation section 38 And

The quadrature modulator 38 performs D / A conversion processing on the I-axis data and the Q-axis data output from the control signal modulator 37 based on the reproduced clock signal output from the timing signal generator 21. Two D / A conversion circuits 4
2 and 43; two LPF circuits 44 and 45 for low-pass filtering the I-axis signal and the Q-axis signal output from the D / A conversion circuits 42 and 43;
7, a multiplication circuit 46 that multiplies the quadrature modulated clock signal output from the quadrature clock generation unit 23 and the I-axis signal output from the LPF circuit 44 to generate an I-axis IF signal.
And a π / 2 circuit 47 for shifting the phase of the orthogonal modulation clock signal output from the orthogonal clock generator 23 by π / 2, and the phase is shifted by π / 2 output from the π / 2 circuit 47. Quadrature modulated clock signal and LPF circuit 4
5, a multiplication circuit 48 that generates a Q-axis IF signal by multiplying the Q-axis signal output from the multiplication circuit 5, and an I-axis output signal from the multiplication circuit 46 and the Q-axis IF signal output from the multiplication circuit 48. An adder circuit 49 is provided to generate an IF signal by synthesizing the IF signal with the side IF signal and supply the generated IF signal to the transmission device 19.

Next, referring to the schematic diagram shown in FIG.
The operation of the bidirectional transmission method 1a of the OFDM signal shown in FIG. 1 will be described with an example of transmission / reception from a mobile body applied to the case of performing a marathon relay.

Now, the first transmitting / receiving device 5 is mounted on a moving body 50 such as a vehicle, and the first and second receiving stations 51,
52, the second transmitting / receiving devices 7 are arranged,
0 transmits an OFDM radio wave 3 to the first receiving station 5.
1. It is assumed that the signal is received by one of the second receiving stations 52.

Under such preconditions, first, the OFDM radio wave 3 transmitted from the mobile unit 50 is transmitted to the first receiving station 51.
, A control signal for maintaining the current transmission parameters is input to the second transmitting / receiving device 7 provided in the first receiving station 51. The input control signal is subjected to orthogonal frequency division multiplexing and transmitted as an OFDM radio wave 4 from the first receiving station 51 to the mobile unit 50 side. As a result, the current transmission parameters are continuously used, and the current operation of transmitting the OFDM radio wave 3 from the mobile station 50 is continued.

Thereafter, as the moving body 50 moves, the first
When there is a need to switch the receiving station from the receiving station 51 to the second receiving station 52, the second receiving station 52
The reception of the OFDM radio wave 3 transmitted from 0 starts.

At this time, if the transmission path environment around the second receiving station 52 is bad and correct reception cannot be performed unless strong error correction is performed, the second transmission / reception provided in the second receiving station 52 is performed. For example, a type of error correction that can apply strong error correction to the device 7 and a control signal for changing transmission parameters such as a bit rate and a carrier modulation method accompanying the change, or a burst-like error Time axis that has the effect of dispersing
A control signal or the like that specifies the depth of interleaving on the frequency axis) is input, and is orthogonal frequency division multiplexed to generate an OFDM radio wave 4, which is transmitted from the second receiving station 52 to the mobile unit 50 side.

The O transmitted from the second receiving station 52
When the content of the received OFDM radio wave 4 is decoded, the first transmitting / receiving device 5 of the mobile unit 50 that has received the FDM radio wave 4 decodes the OFDM radio wave 4 transmitted from the second receiving station 52.
The transmission parameter of the OFDM signal is changed on the basis of the control signal indicated by, the new transmission parameter resistant to interference is used, and the OFDM radio wave 3 is generated.
Received by the receiving station 52.

As described above, in the first embodiment,
The first transmission / reception device 5 collects video and audio to be transmitted, converts the collected video and audio into an OFDM radio wave 3, and transmits the OFDM radio wave 3 to the second transmission / reception device to reproduce the video and audio.
In synchronization with the radio wave 3, the control signal input to the second transmission / reception device 7 is turned into an OFDM radio wave 4, transmitted to the first transmission / reception device 5, demodulated the control signal, and transmitted by the first transmission / reception device 5. Since the parameters are optimized, the transmission is synchronized with the OFDM signal from the second point 6 on the reception point side, which receives the information data transmission unit 14 transmitted from the first point 2 which is the transmission point. The control data transmission unit 15 is transmitted to the point side, whereby bidirectional transmission between the transmission point and the reception point can be realized (the effect of claim 1).

In the first embodiment, the control data transmission unit 1 that performs OFDM transmission in the reverse direction from the receiving point side
5, the control data is transmitted, and the information data transmission unit 1
Since the transmission parameters of the transmission point transmitting the data No. 4 are changed, the transmission parameters and the like can be optimized according to the state of the transmission path (effect of claim 3).

<Second Embodiment> FIG. 5 is a block diagram showing a second embodiment of a transmission / reception system for realizing a bidirectional transmission method of an OFDM signal according to the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals.

The transmission / reception system 1b shown in this figure is different from the transmission / reception system 1a shown in FIG. 1 in that the modulation device 10 provided in the first transmission / reception device 5 and the demodulation device 13 are electrically separated. When a peripheral device control signal such as a camera device is input to the second transmission / reception device 7, the signal is modulated by the peripheral device control signal to generate an OFDM radio wave (an OFDM radio wave synchronized with the OFDM radio wave 3 transmitted from the first transmission / reception device 5). )
4 is generated and received by the first transmission / reception device 5, and the peripheral device control signal is reproduced by the demodulation device 13 provided on the first transmission / reception device 5 side.

In this case, the modulation device 18 provided in the second transmission / reception device 7 fetches a timing signal such as a symbol synchronization signal and a reproduced clock signal from the demodulation device 17 provided in the second transmission / reception device 7. And performs modulation processing of the peripheral device control signal.

When the peripheral device control signal is input, the peripheral device control signal is converted to the frequency spectrum of the OFDM radio wave (the OFDM radio wave transmitted from the first transceiver 5) 3 received by the second transceiver 7. For example, as shown in FIG. 6, the frequency spectrum of the control data transmission unit 55 adjacent to the set frequency spectrum of the information data transmission unit 54 has the frequency spectrum of the O transmitted from the first transmission / reception device 5.
The signal is converted into an OFDM radio wave 4 synchronized with the FDM radio wave 3 and transmitted to the first transmitting / receiving device 5 to control a peripheral device such as a camera device on the first transmitting / receiving device 5 side.

As described above, in the second embodiment,
A peripheral device control signal such as a camera device generated by the second transmitting / receiving device 7 is transmitted to the OF device transmitted from the first transmitting / receiving device 5.
The signal is converted into an OFDM radio wave 4 synchronized with the DM radio wave 3, and the first
Since the data is transmitted to the transmission / reception device 5, the control data transmission unit 55 that performs OFDM transmission in the reverse direction from the receiving point side
Thus, a control signal line between the receiving point side and the transmitting point side can be constructed, whereby peripheral devices on the transmitting point side can be remotely controlled from the receiving point side (effect of claim 5).

<Third Embodiment> FIG. 7 is a block diagram showing a third embodiment of a transmission / reception system for realizing a bidirectional transmission method of an OFDM signal according to the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals.

The transmission / reception system 1c shown in FIG. 6 differs from the transmission / reception system 1a shown in FIG. 1 in that a modulation device 10 provided in the first transmission / reception device 5 and a demodulation device 13 are electrically separated. When digital data such as video data and audio data for a program monitor, or digital data such as audio data for a communication line is input to the second transmitting / receiving device 7, the digital data is modulated,
OFDM radio wave (OFD transmitted from the first transceiver 5)
An OFDM radio wave 4 synchronized with the M radio wave 3) is generated and received by the first transmission / reception device 5.
The digital data is reproduced by the demodulation device 13 provided on the side.

In this case, the modulation device 18 provided in the second transmission / reception device 7 takes in timing signals such as a symbol synchronization signal and a reproduction clock signal from the demodulation device 17 provided in the second transmission / reception device 7. Performs modulation processing of digital data.

When the digital data is input, the digital data is transmitted to the OFDM radio wave received by the second transmitting / receiving device 7 (ODM signal transmitted from the first transmitting / receiving device 5).
The frequency spectrum of the FDM radio wave (FDM radio wave) 3, for example, as shown in FIG. 8, has the frequency spectrum of the set information data transmission unit 56 and the frequency spectrum of the control data transmission unit 57 adjacent thereto. OF
It is converted into an OFDM radio wave 4 synchronized with the DM radio wave 3, and the first
The digital data is transmitted to the transmitting / receiving device 5 and reproduced.

As described above, in the third embodiment,
OFDM synchronized with the OFDM radio wave 3 transmitted from the first transmitting / receiving device 5
Since the radio wave 4 is converted to the radio wave 4 and transmitted to the first transmitting / receiving device 5, the control data transmitting unit 57 which performs OFDM transmission from the receiving point in the reverse direction transmits the digital data to the information data transmitting unit. By causing the transmitting point transmitting the signal 58 to receive, various digital data can be transmitted from the receiving point to the transmitting point.
And effect of 6).

In the first, second, and third embodiments described above, the information data transmitting units 14, 54, 56 having the frequency spectrums as shown in FIGS.
Control data transmission units 15, 55, 57 having frequency spectra adjacent to the information data transmission units 14, 54, 56
Thus, bidirectional transmission between the first transmitting / receiving device 5 and the second transmitting / receiving device 7 is realized, and such information data transmitting units 14, 54, 56, control data transmitting units 15, 55,
As shown in FIG. 9, an information data transmission unit 58 and a control data transmission unit 59 which are arranged adjacent to each other in one channel (one transmission band) having a certain frequency band are used instead of It may be used to realize bidirectional transmission between the first transmitting / receiving device 5 and the second transmitting / receiving device 7.

As described above, by determining the contents of each channel, the first transmitting / receiving device 5 and the second transmitting / receiving device 7
, Bidirectional transmission using one channel can be performed (the effect of claim 2).

[0059]

As described above, according to the present invention, according to the first aspect, the frequency band of the OFDM signal is divided into an information data transmission unit for transmitting video data and audio data, and a control data transmission unit for transmitting control data. Frequency division with the transmission unit,
By transmitting a control data transmission unit to the transmission point side in synchronization with the OFDM signal from a reception point side receiving the information data transmission unit transmitted from the transmission point side, bidirectional transmission with adjacent frequency bands Can be realized.

According to a second aspect of the present invention, a channel having a fixed frequency bandwidth is frequency-divided into an information data transmission section for transmitting video data and audio data and a control data transmission section for transmitting control data. From the receiving point side that receives the information data transmitting unit transmitted from the transmitting point side,
By transmitting the control data transmission unit to the transmission point in synchronization with the DM signal, bidirectional transmission with adjacent frequency bands can be realized.

According to a third aspect of the present invention, the control data transmitting unit which performs OFDM transmission in the reverse direction from the receiving point transmits control data, and sets a transmission parameter of the transmitting point transmitting the information data transmitting unit. By changing, transmission parameters and the like can be optimized according to the state of the transmission path.

According to the fourth aspect, digital data such as video / audio information for program monitoring is transmitted by the control data transmission unit which is OFDM-transmitted in the reverse direction from the receiving point, and transmitted to the information data transmission unit. In this case, digital data such as video and audio information for various program monitors can be transmitted from the receiving point to the transmitting point.

According to a fifth aspect of the present invention, the control data transmission unit which performs OFDM transmission from the reception point in the reverse direction transmits control data and controls the transmission point side device transmitting the information data transmission unit. By doing so, it is possible to directly control the camera device and the like on the transmission point side to transmit desired video data and the like.

Further, according to the present invention, the control data transmission unit which performs OFDM transmission from the receiving point in the reverse direction forms a communication line between the receiving point and the transmitting point, so that the control point is transmitted from the receiving point. Various requests can be issued to the transmitting point.

Further, according to claim 7, the received OFDM
In synchronization with the signal, control data for changing transmission parameters such as the type of error correction, accompanying bit rate, carrier modulation, digital data such as video and audio information for program monitoring, control data for device control, Or, the control data transmission section containing any of the digital data for the communication line is directed toward the transmission point side of the information data transmission section.
By providing a transmitting device for DM transmission, bi-directional transmission between the transmission point and the reception point becomes possible, and it is possible to change the transmission parameters on the transmission point side transmitting the information data transmission unit,
The desired video data and the like can be transmitted by directly and remotely controlling the camera device and the like on the transmission point side, and various requests can be issued from the reception point side to the transmission point side.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a transmission / reception system for realizing a bidirectional transmission method of an OFDM signal according to the present invention.

FIG. 2 is a block diagram showing a detailed circuit configuration example of a demodulation device and a modulation device provided in a second transmission / reception device shown in FIG.

FIG. 3 is a schematic diagram illustrating an example of a frequency configuration of each OFDM radio wave transmitted and received by a first transmitting / receiving device and a second transmitting / receiving device illustrated in FIG. 1;

FIG. 4 is a schematic diagram showing an operation example of the transmission / reception system shown in FIG.

FIG. 5 is a block diagram showing a second embodiment of a transmission / reception system for realizing a bidirectional transmission method of an OFDM signal according to the present invention.

6 is a schematic diagram illustrating an example of a frequency configuration of each OFDM radio wave transmitted and received by a first transmitting and receiving device and a second transmitting and receiving device illustrated in FIG. 5;

FIG. 7 is a block diagram showing a third embodiment of a transmission / reception system for realizing a bidirectional transmission method of an OFDM signal according to the present invention.

8 is a schematic diagram illustrating an example of a frequency configuration of each OFDM radio wave transmitted and received by a first transmitting / receiving device and a second transmitting / receiving device illustrated in FIG. 7;

FIG. 9 is a schematic diagram showing an example of the frequency configuration of another OFDM radio wave used in the bidirectional transmission method of an OFDM signal according to the present invention.

[Explanation of symbols]

 1a, 1b, 1c: transmission / reception system 2: first point 3, 4: OFDM radio wave 5: first transmission / reception device 6: second point 7: second transmission / reception device 8: television camera device 9: microphone 10, 18: Modulators 11, 19: Transmitters 12, 16: Receivers 13, 17: Demodulators 14, 54, 56, 58: Information data transmitters 15, 55, 57, 59: Control data transmitters 20: Quadrature detectors 21 : Timing signal generator 22: Video / audio reproducer 23: Quadrature clock generator 24: Variable frequency oscillator 25, 27, 46, 48: Multiplier 26, 47: π / 2 circuit 28, 29, 44, 45: LPF Circuits 30, 31: A / D conversion circuit 32: Synchronous reproduction circuit 33: Variable frequency transmission circuit 34: FFT circuit 35: Differential circuit 36: Phase error detection circuit 37: Control signal Tuning unit 38: Quadrature modulation unit 39: Carrier mapping circuit 40: IFFT circuit 41: Guard synchronization insertion circuit 42, 43: D / A conversion circuit 49: Addition circuit 50: Moving body 51: First receiving station 52: Second reception Station

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shunji Nakahara 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Research Institute (72) Inventor Masayuki Takada 1-110 Kinuta, Setagaya-ku, Tokyo No. Japan Broadcasting Corporation Broadcasting Research Institute (72) Michihiro Uehara 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Research Institute (72) Inventor Masahiro Okano 1-10 Kinuta, Setagaya-ku, Tokyo No. 11 Japan Broadcasting Corporation Research Institute of Broadcasting (72) Inventor Makoto Sasaki 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Research Institute

Claims (7)

[Claims] The frequency band of an OFDM signal is frequency-divided into an information data transmission section for transmitting video data and audio data and a control data transmission section for transmitting control data. At the receiving point, the control data transmitting unit performs OFDM transmission in the reverse direction toward the transmitting point in synchronization with the received OFDM signal, wherein: 2. A method comprising: dividing a channel having a fixed frequency bandwidth into an information data transmitting unit for transmitting video data and audio data and a control data transmitting unit for transmitting control data; At the receiving point of the transmitting section, the control data transmitting section performs OFDM transmission in the reverse direction toward the transmitting point in synchronization with the received OFDM signal, wherein: 3. The bidirectional transmission method of an OFDM signal according to claim 1, wherein the control data transmission unit that performs OFDM transmission in a reverse direction from a receiving point side includes: a type of error correction; , Is configured with control data for changing transmission parameters such as carrier modulation.
Changing a transmission parameter at a transmission point transmitting the information data transmission unit. 4. The bidirectional transmission method of an OFDM signal according to claim 1, wherein the control data transmission section that performs OFDM transmission in a reverse direction from a receiving point side includes a video, audio, and information for a program monitor. A bidirectional transmission method of an OFDM signal, wherein the digital data is received at a transmission point transmitting an information data transmission unit. 5. The bidirectional transmission method of an OFDM signal according to claim 1, wherein the control data transmission unit that performs OFDM transmission in a reverse direction from a receiving point side is configured by control data for controlling a device. And controlling a device at the transmission point transmitting the information data transmission unit with the control data. A bidirectional transmission method of an OFDM signal. 6. The bidirectional transmission method of an OFDM signal according to claim 1 or 2, wherein the control data transmission unit which performs OFDM transmission in a reverse direction from a receiving point side is constituted by digital data for a communication line. ,
A bidirectional transmission method of an OFDM signal, comprising: forming a communication line between a reception point side and a transmission point side by the control data transmission unit. 7. The OF according to any one of claims 1 to 6.
What is claimed is: 1. A transmitting / receiving apparatus provided on a receiving point side of said information data transmitting unit for realizing a bidirectional transmission method of a DM signal, comprising: a type of error correction and a bit rate associated therewith synchronized with a received OFDM signal. , Control data for changing transmission parameters such as carrier modulation, digital data such as video and audio information for program monitoring, control data for equipment control, or digital data for communication lines A transmitting device for performing OFDM transmission with a data transmission unit directed toward a transmission point of the information data transmission unit;