JP2856139B2 - Error correction control method and error correction control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an error correction control method and an error correction control apparatus. For example, three or more slave stations share two or more transmission paths in response to an instruction from a master station to perform communication. The present invention relates to an error correction control method and an error correction control device that are used for a request assignment satellite communication system to be performed and that switch a coding rate to compensate for deterioration in channel quality when the channel quality deteriorates.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Patent Application Laid-Open No. 3-198546, a burst mode inbound signal from a slave station to a master station in a transmission path for transmitting data between the master station and the slave station. , The coding rate is switched to compensate for the deterioration of the line quality. FIG. 2A is a block diagram of a master station having such a configuration, and FIG. 2B is a block diagram of a slave station.

In a master station, a reception signal input from a reception data input terminal 1 for receiving a signal from a slave station is demodulated in a demodulator 2, and the demodulated data 101 is obtained from two types of Viterbi having different coding rates. The output of the decoder 3-1 is input to the decoders 3-1 and 3-2, and the selector 4 selects a preset output of the decoder. Here, the coding rates R of the decoders 3-1 and 3-2 are set to ／ and ２, respectively.
The selected decoded data 102 'is input to the bit error rate measuring circuit 5, where the bit error rate of the data is measured.

[0004] The measured bit error rate data 103 is compared with the contents of the bit error rate prescribed value register 6 in a comparator 7. As a result of the comparison, if the measured bit error rate is worse than the specified value, the comparator 7 generates a pulse 104 in a frame unit or the like. The bit error rate measuring circuit 5 generates a burst pulse 105 every time an inbound signal is received, and together with the comparator output pulse 104, a backward protection and forward protection circuit 8 (hereinafter, referred to as a coding rate changing code rate changing circuit).
Abbreviated as “protection circuit”. ).

The protection circuit 8 has a protection counter,
The input output pulse 104 of the comparator is counted. This protection counter counts only when a pulse continuously comes, and when the protection counter value becomes larger than a certain value, outputs the coding rate change instruction information 106 to the overhead information multiplexing circuit 14 ', and Input terminal 1
The information is multiplexed with the transmission data 107 from No. 3 and information for changing the coding rate of the channel is sent to all slave stations.

[0006] Thereafter, the coding rate information 108 is sent to the selector 4, and the decoders 3-1 and 3-2 suitable for the transmission of the slave station are sent.
The selector 4 is switched so as to select one of the above.
The data 114 multiplexed by the overhead information multiplexing circuit 14 'is encoded by the transmission data encoder 15,
Further, the transmission data transmitting terminal 1 which is modulated by the modulator 16 and transmitted to the slave station.
It is sent to 7.

[0007] In the slave station, a received signal input from a received data input terminal 21 for receiving a signal from the master station is input to a demodulator 23 and a decoder 24 for decoding. The overhead information separation circuit 25 'outputs the decoded data 20
1 'is separated from the overhead information 202' by the CPU 2
Send to 6. The CPU 26 recognizes the transmitted overhead information 202 ′ and sends to the selector 29 coding rate information 203 for selecting an appropriate coding rate. The selector 29 selects one of the Viterbi encoders 28-1 and 28-2 whose coding rates have been changed in the same manner as the master station,
Transmission data 205 input from transmission data input terminal 27
Is encoded and modulated by the modulator 30, and then output to the transmission data transmitting end 32 for transmitting a signal to the master station.

As described above, in a transmission path for transmitting data between a master station and a slave station, the coding rate is changed following the line quality to compensate for the deterioration of the line quality.

In addition, line quality is compensated by TPC control (power control) for a conti-mode outbound signal including information such as monitoring and connection of a line from a master station to a slave station.

[0010]

As described above, in the configuration shown in FIG. 2, since communication is performed using a predetermined frequency band, a problem arises even if the information transmission speed such as data communication slightly changes. If the information transmission speed is determined, such as voice communication, there is a problem that when the error correction capability is enhanced, the transmission capacity becomes insufficient and normal communication cannot be performed.

In the case of applying to a frequency request allocation satellite communication system, a conventional system can be used for a common signal between a master station and a slave station, but a slave station to which a frequency channel is assigned by the common signal. When trying to apply to communication between slave stations, the following problem occurs.

First, if the coding rate of the inbound signal of the common line is changed during communication of voice or the like at the coding rate of the inbound signal determined at the time of the common line,
In order to notify the master station that the communication rate between the slave station and the master station is different when the communication between the slave station and the slave station is completed and the inbound signal does not pass due to a difference between the transmission coding rate of the slave station and the reception coding rate of the master station. You have to wait until you receive polling or broadcast data that changes the coding rate of the inbound signal on the common line,
When there are a large number of slave stations or when the line quality is stable and the coding rate does not need to be changed, there is a problem that the coding rate of the inbound signal cannot be easily determined by the common signal, and charging continues.

Second, in order to compensate for the deterioration of the line quality by switching the coding rate, if it is attempted to transmit a signal which becomes a problem when the information transmission speed of voice or the like is reduced, the transmission speed in the radio section is increased. Because the frequency band used increases,
There is also a problem that there is a risk of causing interference to an adjacent channel. As a countermeasure, it is possible to make the transmission rate in the radio section constant by deleting a part of the speech coded bits so that the transmission rate in the radio section does not increase when the coding rate is switched. In addition, there is a problem that the voice quality is deteriorated, and it is expensive due to a complicated configuration.

The present invention has been made in order to solve such a problem. It is an object of the present invention to control the switching of the coding rate even for a communication signal between slave stations by a simple configuration. An object of the present invention is to provide an error correction control method that can be performed.

Another object of the present invention is to provide an error correction control method which does not cause a shortage of transmission capacity even when the error correction capability is enhanced by switching a coding rate for a communication signal between slave stations. And an error correction control device.

[0016]

An error correction control method according to the present invention is an error correction control method in multi-way multiple access communication comprising a master station and a plurality of slave stations.
The error rate measured by the common signal from the slave station is monitored, coding rate information suitable for the common signal and the communication signal between the slave stations is selected, and the code of the common signal of all slave stations is selected based on the coding rate information. While transmitting the coding rate and instruction information of the coding rate of the communication signal between the slave stations, control the coding rate of the decoder of the master station to match the coding rate of the common signal of all the slave stations,
In the slave station, the coding rate of the common signal and the communication signal between the slave stations is determined based on the coding rate instruction information received from the master station.

Further, the error correction control method according to the present invention further provides the master station with a transmission path having a transmission capacity suitable for communication between slave stations based on coding rate information suitable for communication signals between slave stations. Instruction information is transmitted, and the slave station determines a transmission path for communication between the slave stations based on the transmission path instruction information.

Preferably, the error correction control method is applied to fixed frequency allocation satellite communication or frequency request allocation satellite communication.

Next, as an error correction control device in the master station of the present invention which is directly used for implementing the error correction control method, an error correction controller in a multi-way multiple access communication comprising a master station and a plurality of slave stations is provided. In the control device, decoding means for decoding a received signal at a selected error correction coding rate, measuring means for measuring a bit error rate of decoded data, a common signal and a child signal common to all slave stations based on the bit error rate. Coding rate information selecting means for selecting coding rate information suitable for each communication signal between stations; slave station call detecting means for detecting calling information from the decoded data; and the calling information and the coding. Channel control means for selecting a transmission / reception channel capable of securing communication capacity between calling and called slave stations from the rate information; and transmitting the coding rate information and information on the sending / receiving channel for communication between the slave stations. Transmission data multiplexing means for multiplexing with the transmission data, and a common signal transmission means for transmitting the multiplexed data to each slave station, and transmits the coding rate information and the information of the transmission / reception channel to the slave station, The coding rate of the decoding means of the master station is selected based on the coding rate information of the common signal.

Further, as an error correction control device in a slave station of the present invention, an error correction control device in a slave station of multi-way multiple access communication comprising a master station and a plurality of slave stations is suitable for converting a received signal to a common signal. Demultiplexing means for extracting a coding rate, a coding rate suitable for a communication signal between slave stations for calling and receiving calls and information of a transmission / reception channel, and codes a common signal with a coding rate suitable for the common signal. A common signal transmission / reception device comprising coding means for performing coding, a coding means and a decoding means for coding and decoding a communication signal between slave stations at a coding rate suitable for the communication signal, and the communication signal upon calling or receiving a call. And a channel control means for transmitting and receiving signals through a transmission / reception channel suitable for communication.

Further, there is provided an error correction control device for a multi-directional multiple access communication device comprising a master station and a plurality of slave stations in fixed frequency assignment satellite communication or frequency request assignment satellite communication.
An error correction control device in the master station and the slave station is provided.

More specifically, in a master station using a request allocation satellite communication system in which a plurality of three or more slave stations communicate by sharing two or more transmission paths according to an instruction from the master station. A common signal receiving means for receiving and demodulating a common signal from a slave station; a decoding means for decoding the demodulated received signal with a plurality of decoders having different error correction coding rates; and Selecting means for selecting one of the decoded data output from the decoder of the coding rate, bit error rate measuring means for measuring the bit error rate with the selected decoded data,
Coding rate selecting means for selecting an optimum coding rate for a common signal line common to all slave stations or for a communication signal line of each slave station from the measured bit error rate data, and calling information from the decoded data. Slave station call detecting means to be detected, and each of the stations selected by the coding rate selecting means for the calling slave station and the called slave station detected by the slave station call detecting means. Frequency channel control means for controlling a channel capable of securing the band based on the coding rate, and a coding rate selected by the coding rate selecting means optimal for the common signal line or a communication signal line for each slave station. And transmission data multiplexing means for multiplexing transmission / reception frequency channels used for communication between slave stations / slave stations determined by the channel control means with transmission data, and common signal transmission for modulating the multiplexed data and transmitting the modulated data to each slave station. Means The coding rate of the decoder for the common signal is selected based on the measured bit error rate data, and the coding rate suitable for the communication signal line is selected for each slave station, and a frequency band suitable for the coding rate can be secured. A channel is detected, and a coding rate and a frequency channel suitable for the calling / called side slave station are transmitted to the calling / called side slave station, and the common station transmits and receives a common signal. The common signal transmitting / receiving apparatus comprises a common signal transmitting / receiving apparatus and a communication signal transmitting / receiving apparatus for transmitting / receiving a communication signal. In the common signal transmitting / receiving apparatus, a common signal receiving means for receiving and demodulating a common signal from a master station, and a common signal receiving section for demodulating the received signal. The optimum error correction coding rate for the signal or the optimum error correction coding rate for the communication signal between the slave stations requesting the call and the frequency channel for transmission / reception used for communication between the slave stations are extracted. Error correction coding And frequency channel extraction means, encoding means for encoding a transmission signal with a plurality of encoders having different error correction coding rates, and one of transmission data output from the encoders having the plurality of different error correction coding rates. Selecting means for selecting the optimum error correction coding rate for the common signal according to the optimum error correction coding rate for the common signal, and the transmission / reception frequency channel used for communication between slave stations / slave stations on the calling side. Or a notifying unit for notifying the communication signal transmitting / receiving apparatus on the called side, wherein the communication signal transmitting / receiving apparatus on the calling side or the called side transmits / receives a communication signal to / from another slave station and modulates / demodulates the communication signal. Transmitting and receiving means, encoding means and decoding means for encoding and decoding the communication signal sent from the common signal transmitting and receiving apparatus by an encoder and decoder having an optimal error correction coding rate, and a common signal transmitting and receiving apparatus. Slave station on the frequency channel sent from the
Frequency channel control means for controlling a transmission / reception frequency channel used for communication between slave stations, wherein the common signal transmitting / receiving apparatus performs coding when receiving a simultaneous command coding rate change instruction information from the master station. The communication rate is changed, and the communication signal transmitting and receiving device communicates with another slave station using a frequency channel that secures an appropriate coding rate according to the line quality and a frequency band corresponding to the appropriate coding rate. Is performed.

[0023]

Next, the present invention will be described with reference to the drawings.

FIG. 1A is a block diagram of a master station showing an embodiment of the present invention, and FIG. 1B is a block diagram of a slave station showing an embodiment of the present invention.

When the frequency request allocation satellite communication system is used, communication is performed between the slave stations / slaves after transmitting the communication signal transmission path assignment information from the master station to the slave stations through the common signal transmission path. Here, it is assumed that the slave station has one common signal transmitting and receiving device for transmitting and receiving a common signal, and a plurality of communication signal transmitting and receiving devices for transmitting and receiving communication signals such as voice.

In the master station, a received signal input from a received data input terminal 1 for receiving a signal from a slave station is demodulated in a demodulator 2, and the demodulated data 101 is converted into two types of Viterbi having different coding rates. The output of the decoder 3-1 is input to the decoders 3-1 and 3-2, and the selector 4 selects a preset output of the decoder. Here, the coding rates R of the decoders 3-1 and 3-2 are set to ／ and ２, respectively.
The selected decoded data 102 is input to the bit error rate measurement circuit 5, where the bit error rate of the data is measured. The measured bit error rate data 103 is compared with the contents of the bit error rate prescribed value register 6 in the comparator 7. As a result of the comparison, if the measured bit error rate is worse than the specified value, the comparator 7 generates the pulse 104.

The bit error rate measuring circuit 5 generates a burst pulse 105 every time an inbound signal is received, and the backward and forward protection circuit 8 for changing the coding rate for the common signal together with the comparator output pulse 104; It is assumed that the signals are output to the rear protection and front protection circuits 8 ′ for changing the conversion rate (hereinafter abbreviated as “common signal protection circuits” and “station-specific protection circuits”, respectively). The common signal protection circuit 8 has one protection counter that does not depend on the slave station number, and counts the comparator output pulse 104 input. This protection counter counts only when a pulse continuously comes, and when the protection counter value becomes larger than a certain value, outputs the common signal coding rate change instruction information 106 to the overhead information multiplexing circuit 14; The information is multiplexed with the transmission data 107 from the transmission data input terminal 13 and information for changing the coding rate of the channel for the common signal is sent to all the slave stations as a simultaneous command. After that, the coding rate information 108 is sent to the selector 4, and the selector 4 is switched so as to select one of the decoders 3-1 and 3-2 suited to the transmission of the slave station.

On the other hand, the decoded data 102 is inputted to the slave station number detecting circuit 9 and recognizes from which slave station the measured bit error rate is from, and sends the slave station number notification signal to the protection circuit 8 'for each station. 109 is output. The protection circuit 8 'for each station has a protection counter for each slave station, and counts the input comparator output pulse 104 by a protection counter corresponding to the slave station number indicated by the slave station number notification signal 109. These protection counters communicate in the same manner as the counters of the common signal protection circuit 8 and count only when a pulse comes. When the protection counter value corresponding to the slave station number becomes larger than a certain value, the slave station number notification signal 109 'and the coding rate change instruction signal 11 are stored in the station-specific coding rate storage circuit 11.
Outputs 0. As a result, the station-specific coding rate storage circuit 11 can hold the current optimum coding rate for each slave station. The same operation is performed when the measured bit error rate is improved.

The selected decrypted data 102 is also input to the call request detection circuit 10, where the call request detection circuit 10 detects the slave station requesting the call and sends the data to the protection circuit 8 'for each station. An outgoing / incoming calling station notification signal 112 for notifying the two calling / called stations is transmitted. The protection circuit 8 'for each station which has received the calling / receiving call station communication signal 112 reads out the coding rates 111 of the two slave stations from the coding rate storage circuit 11 for each station, and if the coding rates are the same, the coding rates are reduced. If the coding rates are different, the coding rate with the higher error correction capability, namely 1/2, is output to the overhead information multiplexing circuit 14 and the channel control circuit 12 as the communication signal coding rate information 106 '.

When the channel control circuit 12 receives information of a coding rate of 1/2 having a high error correction capability, it controls to allocate a frequency channel capable of using a frequency band of two channels as a transmission / reception channel for communication signals.
In this way, the channel control circuit 12 sets the transmission / reception channel for communication signal to use one or two channels according to the selected coding rate, and multiplexes the transmission / reception channel information 113 for the communication signal with overhead information. Output to the circuit 14. The overhead information multiplexing circuit 14 includes the communication signal coding rate information 106 '.
The transmission / reception channel information 113 for communication signals is multiplexed with the transmission data 107 from the transmission data input terminal 13. The data 114 multiplexed by the overhead information multiplexing circuit 14 is encoded by the transmission data encoder 15 and further transmitted by the modulator 16 to the transmission data transmitting end 17 to the slave station.
Sent to

If the line quality of the outbound signal in the conti-mode from the master station to the slave station is poor, compensation for the outbound signal is made T.
This is performed under PC control.

In the slave station, a reception signal input from a reception data input terminal 21 for receiving a signal from the master station is transmitted to a common signal transmission / reception device for transmitting / receiving a common signal by a distributor 22 to transmit a communication signal such as voice. The signals are distributed to communication signal transmitting / receiving apparatuses that perform transmission / reception.

In the common signal transmitting / receiving device, the distributor 2
2 are demodulated by a demodulator 23 and a decoder 24.
And decrypted. The overhead information separation circuit 25 separates the overhead information 202 from the decoded data 201 and sends it to the CPU 26. The CPU 26 recognizes the common signal coding rate information 203, the communication signal coding rate information 203 'and the communication signal transmission / reception channel information 204 from the transmitted overhead information 202, and selects the common signal coding rate information 203. 29, the communication signal coding rate information 203 'is sent to the selectors 33 and 29' of the communication signal transmitting / receiving apparatus, and the communication signal transmitting / receiving channel information 204 is sent to the channel control circuit 34 of the communication signal transmitting / receiving apparatus. .

According to the common signal coding rate information 203, the selector 29 selects one of the Viterbi encoders 28-1 and 28-2 whose coding rates have been changed in the same manner as the master station, and sends them to the master station. The transmission data 205 input from the transmission data input terminal 27 of the burst signal is encoded with transmission data 205 corresponding to the changed coding rate and modulated by the modulator 30 and then transmitted from the communication signal transmission / reception apparatus to the combiner 31. Then, the data is combined and output to the transmission data sending terminal 32.

In the communication signal transmitting / receiving device, the distributor 2
The received data separated at 2 is demodulated by a demodulator 23 '. The demodulated data is input to two types of Viterbi decoders 32-1 and 32-2 having different coding rates, and the output of the decoder is selected by the selector 33 according to the communication signal coding rate information 203 '. Similarly, according to the communication signal coding rate information 203 ', the Viterbi encoders 28'-1, 28'
-2, and encodes the transmission data 205 'input from the transmission data input terminal 27' of the communication signal to the other station, modulates the modulated data with the modulator 30 ', and combines the data with the data from the common signal transmitting / receiving apparatus. The data is combined by the device 31 and output to the transmission data sending terminal 32. The channel control circuit 34 that has received the communication signal transmission / reception channel information 204 controls the transmission / reception channel.

In the above-described embodiment, the case of switching between Viterbi encoding and decoding 3/4 and 1/2 has been described.
It is apparent that Viterbi coding and decoding 7/8 and sequential coding and decoding can be similarly considered. In addition, as for the channel control, switching between one channel and two channels has been described, but it is clear that more detailed control is possible.

[0037]

As described above, according to the error correction control system of the present invention, the control of the coding rate in accordance with the channel quality is performed not only when data communication is performed by the fixed frequency allocation satellite communication system, but also when common data communication is performed. By providing one signal transmission / reception device for each slave station, it can be applied to the communication of voice and the like by the frequency request assignment satellite communication system. Also, when the line quality is deteriorated, the code using the frequency band for two channels is used. By switching the conversion rate to improve the line quality, it is possible to perform communication between slave stations / slaves without causing interference to adjacent channels. Moreover, since the coding rate is changed only between slave stations having inferior line quality, the frequency band can be effectively used. Also, there is an excellent effect that communication between slave stations can be performed at a low cost with a simple configuration without adding a large-scale hardware.

[Brief description of the drawings]

FIG. 1A is a block diagram of a master station showing one embodiment of the present invention, and FIG. 1B is a block diagram of a slave station showing one embodiment of the present invention.

FIG. 2A is a diagram illustrating an example of a block diagram of a conventional master station, and FIG. 2B is a diagram illustrating an example of a block diagram of a conventional slave station.

[Explanation of symbols]

1, 21 Received data input terminal 2, 23, 23 'demodulator 3, 24, 32 Viterbi decoder 4, 29, 29', 33 selector 5 bit error rate measurement circuit 6 error rate prescribed value register 7 comparator 8 (common Signal) backward protection and forward protection circuit for changing the coding rate 8 'backward protection and forward protection circuit for changing the coding rate for each station 9 slave station number detection circuit 10 call request detection circuit 11 coding rate storage circuit for each station 12 , 34 Channel control circuit 13, 27, 27 'Transmission data input terminal 14, 14' Overhead information multiplexing circuit 15 Transmission data encoder 16, 30, 30 'Modulator 17, 32 Transmission data transmission terminal 22 Divider 25, 25 'Overhead information separation circuit 26 CPU 28 Viterbi encoder 31 Combiner 101 Demodulated data 102, 102', 201, 201 'Decoded data Data 103 Bit error rate data 104 Comparator output pulse 105 Burst pulse 106 Coding rate change instruction information 106 'Coding rate information 107, 205, 205' for communication signal Transmission data 108, 203 (Common signal Coding rate information 203 'coding rate information for communication signal 109, 109' slave station number notification signal 110 coding rate change instruction signal 111 coding rate for slave station 112 calling and receiving slave station communication signal 113, 204 for communication signal Transmission / reception channel information 114 Multiplexed data 202, 202 'Overhead information

Claims (6)

(57) [Claims] An error correction control method in multi-way multiple access communication comprising a master station and a plurality of slave stations, wherein the master station monitors an error rate measured by a common signal from the slave station, The coding rate information suitable for each communication signal between the slave stations is selected, and the coding rate information transmits the coding rate of the common signal of all the slave stations and the instruction information of the coding rate of the communication signal between the slave stations based on the coding rate information. And the coding rate of the decoder of the master station is controlled so as to match the coding rate of the common signal of all the slave stations. In the slave station, the coding rate of the common signal and the communication signal between the slave stations are controlled. Is determined on the basis of the coding rate instruction information received from the master station. 2. A master station transmits transmission path indication information having a transmission capacity suitable for communication between slave stations based on coding rate information suitable for a communication signal between slave stations. 2. The error correction control method according to claim 1, wherein a transmission path for communication between slave stations is determined based on the transmission path instruction information. 3. The error correction control method according to claim 1, wherein the method is applied to fixed frequency assignment satellite communication or frequency request assignment satellite communication. 4. An error correction control device in a master station for multi-way multiple access communication comprising a master station and a plurality of slave stations, decoding means for decoding a received signal at a selected error correction coding rate, and decoding data Measuring means for measuring the bit error rate of, and coding rate information selecting means for selecting coding rate information suitable for a common signal common to all slave stations and a communication signal between slave stations from the bit error rate, Slave station call detection means for detecting call information from the decoded data; and selecting control of a transmission / reception channel capable of securing a communication capacity between the slave stations for calling and called from the call information and the coding rate information. Channel control means for performing communication; transmission data multiplexing means for multiplexing the coding rate information and transmission / reception channel information for communication between slave stations with transmission data; and a common signal transmitter for transmitting multiplexed data to each slave station. Comprising the door, it transmits the information of the coding rate information and transmitting and receiving channel to the slave station,
An error correction control device, wherein a coding rate of the decoding means of a master station is selected based on coding rate information of the common signal. 5. An error correction control device in a slave station for multi-way multiple access communication comprising a master station and a plurality of slave stations, comprising: a coding rate suitable for a common signal from a received signal; A demultiplexing unit for extracting information on a coding rate and a transmission / reception channel suitable for a communication signal between them, and a common signal transmitting / receiving device including coding means for coding a common signal at a coding rate suitable for the common signal. Coding means and decoding means for coding and decoding a communication signal between slave stations at a coding rate suitable for the communication signal, and channel control means for transmitting and receiving a transmission / reception channel suitable for the communication signal at the time of calling or receiving a call An error correction control device comprising a communication signal transmitting / receiving device comprising: 6. An error correction control device for a multi-way multiple access communication device comprising a master station and a plurality of slave stations in fixed frequency assignment satellite communication or frequency request assignment satellite communication. An error correction control device comprising an error correction control device and the error correction control device for a slave station according to claim 6.