JPH09261143A - Error correction control method and error correction controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate deterioration in channel quality by selecting a coding rate at deterioration in channel quality in the frequency request assignment satellite communication system. SOLUTION: A master station compares error rate data 103 measured by a common signal with a content of a specified value register 6, and a common signal protection circuit 8 and a station dependent protection circuit 8' count the comparison result. When a protection count in the common signal protection circuit 8 obtained from the common signal is higher than a prescribed value, coding rate revision instruction information 106 is sent to all slave stations simultaneously, and a coding rate is controlled and a channel taking a frequency band into account is controlled for called slave stations and a slave station detected by a call request detection circuit 10 storing an optimum coding rate at a current point of time with a station dependent coding rate storage circuit 11 as a result of count by a protection counter in the station dependent protection circuit 8' for each slave station obtained by a communication signal.

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 device, and for example, a plurality of slave stations of three or more stations share communication by sharing two or more transmission paths according to an instruction from a master station. The present invention relates to an error correction control method and an error correction control device, which are used for a demand allocation satellite communication system to be performed, and switch a coding rate to compensate for the deterioration of 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 line for transmitting data between the master station / slave station. With respect to, the coding rate was switched to compensate for the deterioration of the line quality. FIG. 2A shows a block diagram of the master station having the configuration, and FIG. 2B shows a block diagram of the slave station, which will be described below.

In the master station, the reception signal input from the reception data input terminal 1 for receiving the signal from the slave station is demodulated in the demodulator 2, and the demodulated data 101 has two kinds of Viterbi with different coding rates. The output of the decoder, which is input to the decoders 3-1 and 3-2 and preset by the selector 4, is selected. Here, the coding rates R of the decoders 3-1 and 3-2 are set to 3/4 and 1/2, 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.

The measured bit error rate data 103 is compared with the contents of the bit error rate specified value register 6 in a comparator 7. As a result of this comparison, if the measured bit error rate is worse than the specified value, the comparator 7 generates a pulse 104 in frame units. The bit error rate measuring circuit 5 generates a burst pulse 105 each time an inbound signal is received and, together with the comparator output pulse 104, a backward protection and forward protection circuit 8 for changing the coding rate (hereinafter, referred to as
Abbreviated as "protection circuit". ) Is output.

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

After that, 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.
The selector 4 is switched so as to select either of the above.
The data 114 multiplexed by the overhead information multiplexing circuit 14 'is encoded by the transmission data encoder 15,
Further, it is modulated by the modulator 16 and transmitted to the slave station.
It is sent to 7.

In the slave station, the reception signal input from the reception data input terminal 21 for receiving the signal from the master station is input to the demodulator 23 and the decoder 24 for decoding. The overhead information separation circuit 25 'is used for the decoded data 20.
CPU2 with overhead information 202 'separated from 1'
Send to 6. The CPU 26 recognizes the sent overhead information 202 'and sends the coding rate information 203 for selecting a suitable coding rate to the selector 29. The selector 29 selects one of the Viterbi encoders 28-1 and 28-2 whose coding rates are changed in the same manner as the master station,
Transmission data 205 input from the 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.

In this way, in the transmission path for transmitting data between the master station / slave station, the coding rate is changed according to the line quality to compensate for the deterioration of the line quality.

Further, the line quality is compensated by TPC control (power control) for an outbound signal in the continu mode including information such as line monitoring and connection from the master station to the slave station.

[0010]

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

Further, when the present invention is applied to a frequency request allocation satellite communication system, the 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 allocated by the common signal can be used. / When trying to apply to communication between slave stations, the following problems occur.

First, if the coding rate of the inbound signal on the common line is changed during communication of voice or the like at the coding rate of the inbound signal determined on the common line,
When the communication between the slave station / slave station is terminated, the transmission rate of the slave station and the reception rate of the master station are different, the inbound signal does not pass, and in order to notify the master station of the termination You have to wait until you receive the polling or the simultaneous data that changes the coding rate of the inbound signal of the common line,
When there are many slave stations or when the channel quality is stable and it is not necessary to change the coding rate, it is difficult to know the coding rate of the inbound signal by the common signal, and there is a problem that billing continues.

Secondly, when trying to compensate the deterioration of the line quality by switching the coding rate, when trying to transmit a signal which causes a problem when the information transmission rate of voice is lowered, the transmission rate of the wireless section is Since the frequency band used increases,
There is also a problem that it may interfere with the adjacent channel. As a countermeasure against this, a part of the voice coded bits may be deleted so that the transmission rate in the wireless section is constant so that the transmission rate in the wireless section does not increase when the coding rate is switched. However, there is a problem that the voice quality is deteriorated, and it is expensive due to the complicated configuration.

The present invention has been made to solve such a problem, and its object is to control the switching of the coding rate even for a communication signal between a slave station and a slave station with a simple configuration. It 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 in which the transmission capacity does not become insufficient even when the error correction capability is enhanced by switching the coding rate for the communication signals between the slave stations. And to provide an error correction control device.

[0016]

An error correction control method of the present invention is an error correction control method in multidirectional multiple access communication comprising a master station and a plurality of slave stations, wherein the master station is
The error rate measured by the common signal from the slave station is monitored, the 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 by the coding rate information. While transmitting the instruction information of the coding rate of the communication signal between the coding rate and the slave station, the coding rate of the decoder of the parent station is controlled to match the coding rate of the common signal of all the slave stations,
The slave station is characterized in that the coding rates of the common signal and the communication signal between the slave stations are determined based on the coding rate instruction information received from the master station.

Further, the error correction control method of the present invention further includes, in the master station, 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. The instruction information is transmitted, and the slave station determines a transmission path for communication between the slave stations based on the instruction information of the transmission path.

The error correction control method is preferably applied to fixed frequency assigned satellite communication or frequency required assigned satellite communication.

Next, as an error correction control device in the master station of the present invention used directly for carrying out the error correction control method, the error correction in the master station of the multi-directional multiple access communication composed of the master station and a plurality of slave stations. In the control device, the decoding means for decoding the received signal at the selected error correction coding rate, the measuring means for measuring the bit error rate of the decoded data, and the common signal and child common to all slave stations from the bit error rate. Code rate information selecting means for selecting code rate information suitable for each communication signal between stations, slave station call detecting means for detecting call information from the decoded data, the call information and the encoding Channel control means for controlling transmission / reception channel selection capable of securing communication capacity between calling and receiving slave stations from the rate information, and the coding rate information and transmission / reception channel information for communication between the slave stations. Transmission data multiplexing means for multiplexing the received data and the common signal transmitting means for transmitting the multiplexed data to each slave station, and transmitting the coding rate information and transmission / reception channel information to the slave station, and It is characterized in that 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 the error correction control device in the slave station of the present invention, the error correction control device in the slave station of the multi-directional multiple access communication composed of the master station and a plurality of slave stations is suitable for the common signal from the received signal. Decoding means, demultiplexing means for extracting information of transmission / reception channel and encoding rate suitable for communication signals between calling and receiving slave stations, and encoding common signal with encoding rate suitable for said common signal A common signal transmission / reception device including encoding means, encoding means and decoding means for encoding and decoding a communication signal between slave stations at an encoding rate suitable for the communication signal, and the communication signal at the time of calling or receiving a call. It is characterized by comprising a communication signal transmitting / receiving device comprising a channel control means for transmitting / receiving by a transmission / reception channel suitable for.

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

More specifically, in a master station using a request allocation satellite communication system in which a plurality of slave stations of three stations or more communicate with each other by sharing two or more transmission paths according to an instruction from the master station. Is 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 decoder having a plurality of different error correction coding rates, and the plurality of different error corrections. 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,
From the measured bit error rate data, a 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 for each slave station, and calling information from the decoded data The slave station call detecting means for detecting, and the station selected by the encoding rate selecting means for the calling side slave station and the called side slave station detected by the slave station call detecting means A 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 the communication signal line for each slave station. And transmission data multiplexing means for multiplexing the transmission / reception frequency channel used for communication between the slave stations / slave stations determined by the channel control means, and common signal transmission for modulating the multiplexed data and transmitting to each slave station And means A frequency that can select the coding rate of the decoder for the common signal based on the measured bit error rate data, and also select the coding rate suitable for the communication signal line for each slave station and secure the frequency band suitable for the coding rate. Detects a channel, transmits the coding rate and frequency channel suitable for the caller / callee slave station to the caller / callee slave station, and the slave station transmits / receives a common signal. A common signal transmitting / receiving device and a communication signal transmitting / receiving device for transmitting / receiving communication signals. In the common signal transmitting / receiving device, common signal receiving means for receiving and demodulating the common signal from the master station and common for the demodulated received signal Extract the optimum error correction coding rate for signals or the optimum error correction coding rate for communication between slave stations / slave stations requesting a call and the transmission / reception frequency channel used for communication between slave stations / slave stations Error correction coding And frequency channel extraction means, coding means for coding a transmission signal by a plurality of encoders having different error correction coding rates, and one of transmission data output from the plurality of encoders having different error correction coding rates Selecting means according to the optimum error correction coding rate for the common signal, and the optimum error correction coding rate of the communication signal and a frequency channel for transmission and reception used for communication between the slave station and the slave station Or a communication means for notifying the communication signal transmitting / receiving device of the called side, and in the communication signal transmitting / receiving device of the calling side or the called side, a communication signal for transmitting / receiving and modulating / demodulating a communication signal with another slave station The transmitting / receiving means, the encoding means and the decoding means for encoding / decoding by the encoder / decoder having the optimum error correction coding rate of the communication signal sent from the common signal transmitting / receiving device, and the common signal transmitting / receiving apparatus. On the frequency channel sent from
Frequency channel control means for controlling the frequency channel of transmission / reception used for communication between slave stations, and the common signal transmitting / receiving device encodes when the encoding rate change instruction information of the simultaneous command from the master station is received. Change the rate, and in the communication signal transmitter / receiver, communicate with other slave stations on a frequency channel that secures an appropriate coding rate according to the line quality and a frequency band corresponding to the appropriate coding rate. It is characterized by performing.

[0023]

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

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

In the master station, the reception signal input from the reception data input terminal 1 for receiving the signal from the slave station is demodulated in the demodulator 2, and the demodulated data 101 has two kinds of Viterbi with different coding rates. The output of the decoder, which is input to the decoders 3-1 and 3-2 and preset by the selector 4, is selected. Here, the coding rates R of the decoders 3-1 and 3-2 are set to 3/4 and 1/2, 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. The measured bit error rate data 103 is compared with the contents of the bit error rate specified 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 each time an inbound signal is received and, together with the comparator output pulse 104, a common signal coding rate changing rear protection and front protection circuit 8 and a code for each station. The signal is output to the rear protection and front protection circuit 8'for changing the conversion rate (hereinafter abbreviated as "common signal protection circuit" and "station protection circuit", respectively). The common signal protection circuit 8 has one protection counter that does not depend on the slave station number, and counts the input comparator output pulse 104. The protection counter counts only when the pulses are continuously received, and outputs the common signal coding rate change instruction information 106 to the overhead information multiplexing circuit 14 when the protection counter value exceeds a certain value. It 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 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 suitable for the transmission of the slave station.

On the other hand, the decoded data 102 is input to the slave station number detection circuit 9, recognizes from which slave station the measured bit error rate is, and sends the slave station number communication signal to the station protection circuit 8 '. 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 the protection counter corresponding to the slave station number indicated by the slave station number communication signal 109. These protection counters communicate with each other 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 communication 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 coding rate storage circuit for each station 11 can hold the optimum coding rate at the present time for each slave station. The same operation is performed when the measured bit error rate is improved.

The selected decoded data 102 is also input to the call request detection circuit 10, and the call request detection circuit 10 detects the slave station requesting the call and issues it to the protection circuit 8'for each station. An outgoing / incoming call slave station contact signal 112 for communicating the two slave stations of the calling side / the called side is transmitted. The station protection circuit 8 ', which has received the incoming / outgoing call slave station contact signal 112, reads out the coding rates 111 of the two slave stations from the station coding rate storage circuit 11, and if the coding rates are the same, the coding rates are determined. If the coding rates are different, the coding rate having the higher error correction capability, that is, 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 the information of the coding rate 1/2 having a high error correction capability, it controls the frequency channels that can use the frequency band of two channels as the transmission / reception channels for communication signals.
In this way, the channel control circuit 12 sets the communication signal transmission / reception channel so as to use one channel or two channels according to the selected coding rate, and multiplexes the communication signal transmission / reception channel information 113 with the overhead information. Output to the circuit 14. The overhead information multiplexing circuit 14 uses the communication signal coding rate information 106 '.
And 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 modulated by the modulator 16 to transmit the transmission data to the slave station 17.
Sent to

Further, if the line quality of the outbound signal in the conti mode from the master station to the slave station is poor, the compensation is made by T.
It is controlled by PC.

In the slave station, the reception signal input from the reception data input terminal 21 for receiving the signal from the master station is transmitted between the common signal transmitting / receiving device for transmitting / receiving the common signal in the distributor 22 and the communication signal such as voice. It is distributed to the communication signal transmitting / receiving devices for transmitting / receiving.

In the common signal transmitting / receiving device, the distributor 2
The received data separated in 2 are demodulator 23 and decoder 24.
And is 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 transmitting / receiving channel information 204 from the transmitted overhead information 202, and selects the common signal coding rate information 203 from the selector. 29, the communication signal coding rate information 203 'is sent to the selectors 33, 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. .

The selector 29 selects one of the Viterbi encoders 28-1 and 28-2 whose coding rates are changed in the same manner as the parent station according to the common signal coding rate information 203, and sends it to the parent station. Of the burst signal, the transmission data 205 inputted to the transmission data input terminal 27 is encoded and modulated by the modulator 30, and then transmitted from the communication signal transmitting / receiving device to the synthesizer 31. The data is combined and output to the transmission data sending end 32.

In the communication signal transmitting / receiving device, the distributor 2
The received data separated by 2 is demodulated by the 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' are provided.
2 is selected, the transmission data 205 'input from the transmission data input end 27' of the communication signal to the partner station is encoded and modulated by the modulator 30 ', and then combined with the data from the common signal transmitting / receiving device. The data is combined by the device 31 and output to the transmission data sending end 32. Further, the channel control circuit 34 which has received the communication signal transmission / reception channel information 204 controls the transmission / reception channel.

In the above embodiment, the case of switching between Viterbi encoding and decoding 3/4 and 1/2 has been described.
It is obvious that the Viterbi encoding / decoding 7/8 and the sequential encoding / decoding can be similarly considered. Also, regarding the channel control, the switching between channel 1 and channel 2 has been described, but it is also clear that finer control is possible.

[0037]

As described above, according to the error correction control system of the present invention, the control of the coding rate according to the line quality is performed not only in the data communication by the fixed frequency allocation satellite communication system but also in the common communication. By providing one signal transmitting / receiving device for each slave station, it can be applied to the case where voice communication is performed by the frequency request allocation satellite communication method, and when the line quality deteriorates, the frequency band for two channels is used to code. By changing the conversion rate to improve the line quality, it becomes possible to perform communication between the slave stations / slave stations without giving interference to the adjacent channel. Moreover, since the coding rate is changed only between the slave stations with poor channel quality / slave station, the frequency band can be effectively used. Further, there is an excellent effect that the slave station / communication between slave stations can be performed at a low cost with a simple configuration without adding a large-scale hardware.

[Brief description of 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.

FIG. 2A is a diagram showing an example of a block diagram of a conventional master station, and FIG. 2B is a diagram showing 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 specified value register 7 Comparator 8 (common (For signal) code rate changing backward protection and forward protection circuit 8'Station-based coding rate changing backward protection and forward protection circuit 9 Slave station number detection circuit 10 Call request detection circuit 11 Station-based coding rate storage circuit 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 Distributor 25, 25 'Overhead information separation circuit 26 CPU 28 Viterbi encoder 31 Combiner 101 Demodulated data 102, 102', 201, 201 'Decoding data Data 103 bit error rate data 104 comparator output pulse 105 burst pulse 106 (for common signal) coding rate change instruction information 106 'communication signal coding rate information 107, 205, 205' transmission data 108, 203 (common signal) Coding rate information 203 'Communication signal coding rate information 109, 109' Slave station number communication signal 110 Coding rate change instruction signal 111 Slave station coding rate 112 Incoming and outgoing call slave station communication signal 113, 204 For communication signal Transmission / reception channel information 114 Multiplexed data 202, 202 'Overhead information

Claims (6)

[Claims] 1. An error correction control method in multi-directional 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, Coding rate information suitable for each communication signal between the slave stations is selected, and the coding rate information transmits the instruction information of the coding rate of the common signal of all slave stations and the coding rate of the communication signal between the slave stations. In addition, 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, and in the slave station, the coding rate of the common signal and the communication signal between the slave stations is controlled. Is determined based on the coding rate instruction information received from the master station. 2. The master station transmits instruction information of 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, and the slave station: 2. The error correction control method according to claim 1, wherein the transmission line for communication between the slave stations is determined based on the instruction information of the transmission line. 3. The error correction control method according to claim 1, which is applied to fixed frequency assigned satellite communication or frequency required assigned satellite communication. 4. An error correction control device in a master station for multidirectional multiple access communication comprising a master station and a plurality of slave stations, a decoding means for decoding a received signal at a selected error correction coding rate, and decoded data. Measuring means for measuring the bit error rate, 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, A slave station call detection means for detecting call information from the decoded data, and transmission / reception channel selection control capable of ensuring communication capacity between the call and called slave stations from the call information and the coding rate information. Channel control means for performing, transmission data multiplexing means for multiplexing the coding rate information and transmission / reception channel information for communication between the slave stations with transmission data, and a common signal transmitter for transmitting the 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 apparatus, wherein the coding rate of the decoding means of the master station is selected based on the coding rate information of the common signal. 5. An error correction control device in a slave station for multi-directional multiple access communication comprising a master station and a plurality of slave stations, wherein the slave station has a coding rate suitable for a common signal from a received signal, and an outgoing call and an incoming call. A common signal transmission / reception apparatus including a demultiplexing unit that extracts a coding rate and transmission / reception channel information suitable for a communication signal between the two, and a coding unit that codes a common signal at a coding rate suitable for the common signal. , A coding means and a decoding means for coding and decoding a communication signal between the slave stations at a coding rate suitable for the communication signal, and a channel control means for transmitting and receiving by a transmission / reception channel suitable for the communication signal at the time of calling or receiving a call. An error correction control apparatus comprising a communication signal transmitting / receiving apparatus including: 6. An error correction control device for a multidirectional multiple access communication device comprising a master station and a plurality of slave stations in fixed frequency allocation satellite communication or frequency request allocation satellite communication, the master station according to claim 4. An error correction control apparatus comprising the error correction control apparatus and the slave station error correction control apparatus according to claim 6.