JP5487135B2 - Transmission / reception system and signal transmission method - Google Patents

Description

  Embodiments described herein relate generally to a transmission / reception system that transmits a video and audio in a multiplexed frame structure and a signal transmission method used in this system.

  In a transmission / reception system typified by the G703 standard (6.312M digital interface) and transmitting a plurality of digital transmission lines via an asynchronous digital hierarchy network, the multiplexer that forms the core of the transmission / reception system is configured to set an input signal in advance. Multiplexing is performed using the multiple frames. Here, the multiplex frame defines a sequence of bits when signals are multiplexed. It is no exaggeration to say that how to compose multiple frames will lead to development volume, such as ease of device creation and simplification.

  By the way, when the multiplexing device has a wireless communication function, a symbol clock is defined for each transmission capacity of a digital signal transmitted by the transmission / reception system. The multiplexing device must multiplex and transmit all necessary data within the range of this symbol clock. For example, the multiplexer receives 6.312M digital interface × N1, 64K digital interface × N2, and meeting line data × N3 (N1 / N2 / N3 is an arbitrary positive number), and these data, additional bits, etc. Are multiplexed within the range of the symbol clock, and a multiplexed multiplexed signal is output. Since digital signals transmitted by the transmission / reception system are various combinations of the above-described data, there are a plurality of transmission capacities. Since the multiplexing apparatus creates a multiplexed signal using a multiplexed frame corresponding to each transmission capacity, it is necessary to prepare a multiplexing apparatus corresponding to the transmission capacity of the signal to be transmitted in the transmission / reception system.

  However, if the transmission capacities of the signals to be transmitted are different, a multiplexing device corresponding to a new transmission capacity must be prepared, which causes a problem of a rise in development costs and an increase in management due to an increase in types. Even if the above multiplexing process is executed by an FPGA (Field Programmable Gate Array), if it is attempted to support different multiplexed frames, it is necessary to download new data to the FPGA. It is not solved.

JP-A-10-257007

  As described above, conventionally, a multiplex frame is set for each transmission capacity of a signal to be transmitted. Therefore, if the transmission capacity is different, a multiplexing device corresponding to a new transmission capacity must be prepared and developed. There is a problem that the cost increases and the management increases due to an increase in types.

  Therefore, an object is to provide a transmission / reception system capable of generating a multiplexed signal without changing the setting of the device itself even when the transmission capacity of the signal to be transmitted is different, and a signal transmission method used in this system There is to do.

  According to the embodiment, the transmission / reception system receives a digital signal from a plurality of transmission paths, multiplexes and outputs the plurality of digital signals, receives the multiplexed signal, and receives a digital signal for each transmission path. And a receiving device that separates the signal and outputs the signal. The transmission apparatus includes a multiprocessing unit, a modulation unit, and a transmission unit. The multiplex processing unit has in advance a multiplex frame in which a first time slot for storing bit data of a digital signal is set assuming a maximum required transmission capacity, and the bit data of the plurality of digital signals is Of the set first time slots, a multiplexed signal is created by storing in the first assigned time slot assigned according to the transmission capacity of the plurality of digital signals. The modulation unit receives the multiplexed signal, extracts bit data stored in the first assigned time slot, and converts the extracted bit data into a modulation signal based on a preset modulation scheme. The transmission unit converts the frequency of the modulation signal from the modulation unit into a transmission frequency band, and transmits it as a transmission signal. The receiving apparatus includes a receiving unit, a demodulating unit, and a separation processing unit. The receiving unit receives the transmission signal, converts the frequency of the transmission signal, and uses the modulated signal as the modulated signal. The demodulation unit demodulates the modulation signal from the reception unit by a demodulation method according to the modulation method, stores the demodulated bit data in the first assigned time slot of the multiplex frame, and create. The separation processing unit separates and outputs the multiplexed signal from the demodulation unit into a digital signal for each transmission path.

It is a block diagram which shows the function structure of the transmission / reception system of embodiment. It is a figure which shows the structural example of the multiplex frame set by the multiplex processing part of FIG. It is a figure which shows the structural example of the multiplex frame set by the multiplex processing part of FIG.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a functional configuration of a transmission / reception system according to this embodiment. The transmission / reception system shown in FIG. 1 is, for example, a transmission system that transmits digital signals from a plurality of digital transmission paths typified by the G703 standard over an asynchronous digital hierarchy network. The transmission / reception system includes a transmission device 10 and a reception device 20. The transmission device 10 and the reception device 20 are connected by a digital hierarchy network.

  The asynchronous transmitter 10 has a structure that can accommodate a maximum of 16 312M digital interface transmission paths (hereinafter referred to as transmission paths). Note that the number of transmission paths accommodated in the transmission device 10 can be changed according to the situation in which the transmission / reception system is used.

  The transmission device 10 includes a multiplex processing unit 11, a modulation unit 12, and a transmission unit 13.

  The multiplex processing unit 11 multiplexes the digital signal from the accommodated transmission path according to the multiplex frame shown in FIGS. 2 and 3 are schematic diagrams illustrating an example of a configuration of a multiplex frame recorded in advance in the multiplex processing unit 11 according to the present embodiment. Here, the multiplex frame defines a sequence of bits when signals are multiplexed.

  The multiplex frame according to the present embodiment is set assuming that 16 transmission lines are accommodated. As shown in FIG. 2, the multiplexed frame constitutes one frame by eight subframes. Each subframe includes time slots 1-0, 2-0, 1-1, 2-2,..., 1-293, 2-293, and time slots 1-S1, 2-S1,. There are 8 series consisting of 2-S3. In each of the time slots 1-0, 1-1, 1-2,..., 1-293 and the time slots 2-0, 2-1, 2-2,. Can be stored. Additional bits are stored in the time slots 1-S1 to 1-S3 and the time slots 2-S1 to 2-S3. Here, the payload indicates a data portion transmitted through the transmission path. The additional bits include, for example, a stuff control bit and a synchronization bit.

  The number of time slots 1-0, 1-1,..., 1-293 and time slots 2-0, 2-1,..., 2-293 is based on the number of bits for the capacity of one transmission line. There are also many settings. This is because the input digital signal is stuff-multiplexed based on the desired stuff ratio. That is, since the transmission capacity is larger than the input digital signal, it is necessary to insert invalid data as data. The staff bit plays that role. That is, the stuff bit is for adjusting the difference in the transmission speed of the digital signal for each transmission path. The staff rate per transmission line is also set in advance so as to be always constant regardless of increase or decrease in transmission capacity. Whether or not the payload stored in the time slot is a stuff bit is indicated by the stuff control bit.

  In addition, in the multiplex frame, the position of the time slot for storing the payload or additional bits is set in advance according to the transmission capacity of the digital signal transmitted by the transmission / reception system. For example, when the transmission capacity of a digital signal transmitted by the transmission / reception system corresponds to one transmission line, the payload is the time slot 1-0, 1-1, 1-2,. As the transmission capacity increases, the number of storable time slots 1-0, 1-1, 1-2,..., 1-293 increases. At this time, the additional bits are stored in time slots 1-S1 to 1-S3 of sequence 1 in the multiplex frame, and the number of sequences of storable time slots 1-S1 to 1-S3 increases as the transmission capacity increases. To increase.

  Also, when the number of accommodated transmission lines is equivalent to nine, the payload is transferred from time series 1 to time series 1-0, 1-1, 1-2,. In addition, the time slot 2-0, 2-1, 2-2, which can be stored in the time slot 2-0, 2-1, 2-2,. 2,..., 2-293 increase the number of series. At this time, the additional bits are stored in the time slots 2-S1 to 2-S3 of the sequence 1 in addition to the time slots 1 to S1 to 1-S3 of the sequence 1 to the sequence 8 in the multiplex frame, thereby increasing the transmission capacity. Accordingly, the number of time slots 2-S1 to 2-S3 that can be stored increases.

  The multiprocessing unit 11 includes time slots 1-0, 2-0, 1-1, 2-2,..., 1-293, 2-293 and time slots 1-S1, 2-S1,. In 2-S3, the payload and additional bits are stored in a time slot corresponding to the transmission capacity of the digital signal transmitted by the transmission / reception system, and a multiplexed signal is created. The multiplex processing unit 11 outputs the generated multiplexed signal to the modulation unit 12. It is assumed that the transmission capacity of the digital signal transmitted by the transmission / reception system is determined before the use of the transmission / reception system is started. Hereinafter, the transmission capacity determined before the start of use is referred to as a set capacity.

  The modulator 12 receives the multiplexed signal from the multiplexing processor 11 and extracts the payload and additional bits stored in the time slot corresponding to the set capacity. The modulation unit 12 modulates the extracted payload and additional bits using a preset modulation scheme, and outputs a modulated signal to the transmission unit 13. Note that there are 128QAM, 16QAM, 4PSK and the like as preset modulation schemes.

  The transmission unit 13 converts the modulation signal from the modulation unit 12 into a transmission signal in the transmission frequency band. And the transmission part 13 amplifies the electric power of a transmission signal, and transmits outside.

  The receiving device 20 illustrated in FIG. 1 includes a receiving unit 21, a demodulating unit 22, and a separation processing unit 23.

  The receiving unit 21 receives the transmission signal transmitted from the transmission device 10 and amplifies the power. The receiving unit 21 converts the amplified signal into an intermediate frequency (IF) signal in the intermediate frequency band, and the receiving unit 21 outputs the IF signal to the demodulating unit 22.

  The demodulator 22 demodulates the IF signal from the receiver 21 by a demodulation method corresponding to the modulation method in the modulator. At this time, the demodulating unit 22 stores the demodulated bit data in a time slot corresponding to the set capacity by using the multiplexed frame shown in FIGS. Then, the demodulation unit 22 outputs the multiplexed signal after storing the demodulated bit data to the separation processing unit 23.

  The separation processing unit 23 separates the multiplexed signal from the demodulation unit 22 according to the number of transmission lines accommodated in the reception device 20. At this time, the separation processing unit 23 determines whether or not the payload stored in the predetermined time slot is a stuff bit based on the stuff control bit in the additional bit, and each separated signal is obtained as 6.31M. Convert to a digital signal. The separation processing unit 23 outputs the digital signal of 6.312M to each transmission path that accommodates the digital signal.

  Next, the operation of the transmission / reception system configured as described above will be described using an example in which four transmission paths are accommodated in each of the transmission device 10 and the reception device 20.

  When receiving the 6.312M × 4 digital signal, the multiplex processing unit 11 stores the payload in the time slots 1-0, 1-1, 1-2,. The additional bits are stored in time slots 1-S1 to 1-S3 of 1 to series 4. At this time, for example, it is assumed that stuff control bits are stored in time slot 1-S1 of sequence 1 in subframe 2, and stuff bits are stored in time slot 1-2 of sequence 1. This stuff control bit controls whether or not the payload stored in the time slot 1-2 of the series 1 is a stuff bit. In this embodiment, one stuff control bit is used. However, a plurality of odd-numbered stuff control bits may be stored for each series, and one control having a larger number may be employed. In this case, the stuff control bit can be read even when the communication becomes unstable. The multiplex processing unit 11 outputs the multiplexed signal storing the payload and additional bits as described above to the modulation unit 12.

  The modulation unit 12 has a set capacity of 6.312M × 4 corresponding to four transmission lines, so that the time slots 1-0, 1-1, 1-2,. And the additional bits are extracted from time slots 1-S1 to 1-S3 of series 1 to series 4. The modulation unit 12 modulates the extracted payload and additional bits and outputs a modulated signal to the transmission unit 13.

  The transmission unit 13 converts the modulation signal from the modulation unit 12 into a radio signal and transmits it to the outside.

  The receiving device 20 receives a radio signal from the transmitting device 10. The reception unit 21 converts the radio signal into an IF signal and outputs the IF signal to the demodulation unit 22.

  The demodulator 22 demodulates the IF signal from the receiver 21. The demodulator 22 stores the bits corresponding to the payload in the demodulated bit data in the time slots 1-0, 1-1, 1-2,... The corresponding bit is stored in time slot 1-S1 to 1-S3 of series 1 to series 4. The demodulation unit 22 outputs the multiplexed signal storing the payload and additional bits to the separation processing unit 23.

  The separation processing unit 23 stores payloads in time slots 1-0, 1-1, 1-2,..., 1-293 of the series 1 to the series 4, and the time slots 1-S1 to 1 of the series 1 to the series 4 When additional bits are stored in S3, the multiplexed signal is separated into four signals corresponding to each series. Based on the stuff control bit stored in time slot 1-S1 of sequence 1 in subframe 2, separation processing unit 23 determines whether the payload stored in time slot 1-2 of sequence 1 is a stuff bit. Judging. The separation processing unit 23 considers the presence of the stuff bit, converts each of the four signals into a 6.312M digital signal, and outputs this signal to each transmission path.

  As described above, in the above embodiment, a multiplex frame capable of transmitting the required maximum transmission capacity is set in advance. Then, based on the transmission capacity of the signal transmitted by the transmission / reception system, a necessary signal in the multiplexed frame is used to create a multiplexed signal. As a result, it is possible to cope with an arbitrary transmission capacity without changing the configuration of the multiplexed frame.

  In the above embodiment, the multiplex frame is designed so that the stuff rate per transmission line is always constant regardless of the increase or decrease of the transmission capacity. Therefore, even when the transmission capacity increases or decreases, the storage area in the multiplex frame only changes, and the multiplex frame itself does not need to be changed. That is, it is possible to cope with an arbitrary transmission capacity with one multiplex frame.

  Therefore, according to the transmission / reception system according to the present embodiment, a multiplexed signal can be generated without changing the setting of the apparatus itself even when the transmission capacity of the digital signal transmitted by the transmission / reception system is different.

  In the present embodiment, the case where the transmission / reception system accommodates a plurality of 6.31M digital interface transmission lines has been described as an example, but the present invention is not limited to this. For example, the transmission / reception system may include a plurality of 64K digital interface transmission paths. At this time, the multiplex processing unit 11 multiplexes the audio data transmitted through the 64K digital interface transmission path as additional bits. The additional bits include stuff control bits for audio data.

  In the present embodiment, a multiplex frame is constructed with 16 6.312M digital interface transmission lines as the maximum required number (transmission capacity). However, the number of transmission lines is limited to 16. is not. As long as it is the maximum transmission capacity required in the transmission / reception system, it may be other than 16.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Transmission apparatus 11 ... Multiplexing process part 12 ... Modulation part 13 ... Transmission part 20 ... Reception apparatus 21 ... Reception part 22 ... Demodulation part 23 ... Separation processing part

Claims (5)

A transmission device that receives digital signals from a plurality of transmission paths, multiplexes and outputs the plurality of digital signals;
A receiver that receives the multiplexed signal and separates and outputs the digital signal for each transmission path;
The transmitter is
A plurality of frames in which a first time slot for storing bit data of a digital signal is set in advance, and the bit data of the plurality of digital signals is converted into the plurality of digital signals among the set first time slots. A multiplex processing unit that creates a multiplexed signal by storing in a first allocated time slot allocated according to the transmission capacity of the signal;
A modulation unit that receives the multiplexed signal, extracts bit data stored in the first allocation time slot, and converts the extracted bit data into a modulation signal based on a preset modulation scheme;
A transmission unit that converts the frequency of the modulation signal from the modulation unit to a transmission frequency band and transmits the transmission signal as a transmission signal;
The receiving device is:
A receiving unit that receives the transmission signal, converts a frequency of the transmission signal, and sets the modulated signal;
A demodulator that demodulates the modulated signal from the receiver by a demodulation method corresponding to the modulation method, stores the demodulated bit data in the first assigned time slot of the multiplex frame, and creates a multiplex signal When,
A transmission / reception system comprising: a demultiplexing unit that demultiplexes and outputs a multiplexed signal from the demodulation unit into a digital signal for each transmission path. The multiple frame is further set with a second time slot for storing additional bits,
The multiplex processing unit stores the additional bits in a second assigned time slot assigned according to a transmission capacity of the plurality of digital signals among the set second time slots, and stores the multiplexed signal. Create
The modulation unit receives the multiplexed signal, further extracts additional bits stored in the second allocation time slot, and converts the extracted bit data and additional bits into a modulation signal based on a preset modulation scheme. Converted,
The demodulator demodulates the modulated signal from the receiver by the demodulation method, stores demodulated bit data in the first assigned time slot of the multiplexed frame, and adds the demodulated additional bits to the multiplexed Storing in the second assigned time slot of the frame to create a multiplexed signal;
The demultiplexing unit demultiplexes the multiplexed signal from the demodulation unit for each transmission path, processes the bit data based on the additional bits for each transmission path, and outputs the digital signal as a digital signal. The transmission / reception system according to claim 1.   The additional bit includes a stuff control bit indicating whether or not bit data stored in a designated time slot designated in advance among the set first time slots is a stuff bit. The transmission / reception system according to claim 2. The digital signal includes an audio signal,
The transmission / reception system according to claim 2, wherein the additional bits include audio bit data. A transmission device that receives digital signals from a plurality of transmission paths, multiplexes and outputs the plurality of digital signals, and a reception apparatus that receives the multiplexed signals and separates and outputs the digital signals for each transmission path; A signal transmission method used in a transmission / reception system comprising:
It has in advance a multiple frame in which a first time slot for storing bit data of a digital signal is set,
The bit data of the plurality of digital signals is stored in the first assigned time slot assigned according to the transmission capacity of the plurality of digital signals among the set first time slots to create a multiplexed signal. And
Extracting bit data stored in the first assigned time slot from the multiplexed signal;
The extracted bit data is converted into a modulation signal based on a preset modulation method,
The frequency of the modulated signal is converted to a transmission frequency band and transmitted as a transmission signal,
Receiving the transmission signal;
The frequency of the received transmission signal is converted into the modulated signal,
Demodulate the modulated signal after the frequency conversion by a demodulation method according to the modulation method,
Storing the demodulated bit data in the first allocated time slot of the multiplex frame to create a multiplex signal;
A signal transmission method, wherein the multiplexed signal is separated into a digital signal for each transmission path and output.

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