JPH1065606A - Digital radio communication system and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide digital radio communication system/equipment which appropriately select an error correction code used for communication in accordance with peripheral radio environment where communication is performed, reduce transmission line errors and reduce the deterioration of communication quality. SOLUTION: In the digital radio communication system, base stations A1-C1 and terminal stations A2-F2 are provided and radio communication is performed between the base stations and the terminal stations. The base stations select the combination of a frequency and a convolution code, in which the transmission error becomes a minimum against noise around the base stations, inform the terminal stations of the selected combination and execute communication by using the frequency and the convolution code of the selected combination. Thus, the error correction code used in communication is appropriately selected in accordance with peripheral radio environment where communication is performed, the transmission line errors are reduced and the deterioration of communication quality is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital radio communication system comprising a base station and a terminal station for performing radio communication between the base station and the terminal station and between the base stations, and a base station of the digital radio communication system. And a digital radio communication device constituting a terminal station.

[0002]

2. Description of the Related Art In recent years, high-performance digital radio communication devices have been developed, and various digital radio communication systems using the same have been studied.

Hereinafter, a conventional digital radio communication apparatus and a digital radio communication system using the same will be described.
This will be described with reference to the drawings.

FIGS. 9A and 9B are block diagrams showing a transmitter and a receiver constituting a digital radio communication device used in a conventional digital radio communication system. The transmitter shown in FIG. 9A includes an encoder and a transmitter, and the receiver illustrated in FIG. 9B includes a receiver and a decoder.

[0005] The operation of the transmitter and the receiver of the digital radio communication apparatus configured as described above will be briefly described. In the transmitter shown in FIG. 9A, transmission data input to an encoder is encoded, the encoded data modulates a carrier signal by the transmitter, and the modulated carrier signal is power-amplified and transmitted. It is radiated as radio waves from an antenna (not shown). In the receiver shown in FIG. 9B, a reception signal output from a reception antenna (not shown) that has received an incoming radio wave is demodulated by a receiver, and the demodulated reception signal is decoded by a decoder and received. Output as data.

[0006]

In such a digital radio communication apparatus, a frequency (channel) used for communication and a transmission line error correction code are appropriately selected in accordance with the surrounding radio wave environment in which communication is performed. There is a need to reduce transmission path errors to reduce deterioration of communication quality.

According to the present invention, a transmission line error is reduced by appropriately selecting a frequency (channel) used for communication and a transmission line error correction code according to a surrounding radio wave environment in which communication is performed.
A digital wireless communication device capable of reducing deterioration of communication quality, and a frequency (channel) used for communication and a transmission line error correction code are appropriately selected and transmitted according to a radio wave environment around the communication. An object of the present invention is to provide a digital wireless communication system that reduces path errors and reduces deterioration of communication quality.

[0008]

A digital radio communication system according to the present invention comprises a base station and a terminal station, and performs radio communication between the base station and the terminal station and between base stations. The base station selects a combination of a frequency and a convolutional code that minimizes transmission errors with respect to noise around the base station, and notifies the terminal station of the selected combination. Then, communication is performed using the selected combination of frequency and convolutional code.

Thus, the frequency (channel) used for communication and the transmission path error correction code are appropriately selected according to the surrounding radio wave environment in which communication is performed, thereby reducing transmission path errors and deteriorating communication quality. A reduced digital wireless communication system is obtained.

A digital radio communication apparatus according to the present invention for solving this problem comprises a base station and a terminal station,
A digital wireless communication device constituting the base station of a digital wireless communication system for performing wireless communication between the base station and the terminal station and between the base stations, wherein the digital wireless communication device is configured by setting internal connection information. Encoder capable of generating a convolutional code, a connection information table memory having connection information inside the convolutional encoder for each convolutional code, and a convolutional encoder for generating a convolutional code A state transition table memory having state transition information of an internal register as a state transition table, a decoder capable of decoding an arbitrary convolutional code by setting the state transition information, A signal selector for extracting a control signal indicating a convolutional code from a received signal, and a use frequency (use rate) for each combination of frequency and convolutional code
A frequency / code usage table memory for storing a frequency / code usage rate table in which is recorded, a controller for selecting a frequency and a convolutional code used for communication by the frequency / code usage rate table, and an output from the controller. A code control signal generator that outputs a code control signal to a convolutional encoder and a decoder according to the code switching signal, and a control signal that is output from a data selector and data on a frequency / code usage table. A frequency control signal generator that outputs a frequency control signal to a transmitter and a receiver according to a frequency switching signal output from a controller based on the frequency and a convolutional code control signal output from the controller. And a frequency / code switching signal generator for generating a code switching signal.

[0011] Thus, the frequency (channel) used for communication and the transmission path error correction code are appropriately selected according to the surrounding radio wave environment in which communication is performed, thereby reducing transmission path errors and deteriorating communication quality. A digital radio communication device that can be reduced is obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a base station and a terminal station, and performs a radio communication between the base station and the terminal station and between the base stations. The base station selects a combination of a frequency and a convolutional code that minimizes a transmission error with respect to noise around the base station, notifies the selected combination to the terminal station, and selects the selected combination. The communication is performed using the frequency and the convolutional code, and the communication between the base station and the terminal station is performed at the frequency and the code that minimize the transmission error.

According to a second aspect of the present invention, in the first aspect, the base station can generate an arbitrary convolutional code by setting internal connection information. A connection information table memory having connection information inside the convolutional encoder for each convolutional code, and a state transition having, as a state transition table, state transition information of an internal register of the convolutional encoder for generating the convolutional code A table memory, a decoder capable of decoding an arbitrary convolutional code by setting state transition information, and a signal selector for extracting a control signal indicating a frequency used for communication and a convolutional code from a received signal And the frequency and usage frequency (usage rate) for each combination of frequency and convolutional code.
A frequency / code usage table memory storing a code usage table, and a controller for selecting a frequency and a convolutional code used for communication from the frequency / code usage table,
A code control signal generator that outputs a code control signal to a convolutional encoder and a decoder according to a code switching signal output from the controller, and data on a frequency / code usage rate table and output from a signal selector. A frequency control signal generator that outputs a frequency control signal to a transmitter and a receiver according to a frequency switching signal output from the controller based on the control signal based on the frequency and the convolutional code control signal output from the controller. And a frequency / code switching signal generator for generating a frequency / code switching signal for the station.
This has an effect that a frequency and a convolutional code to be used for communication are selected based on the usage rate of the code usage rate table.

According to a third aspect of the present invention, in the first aspect, the terminal station can generate an arbitrary convolutional code by setting internal connection information. A connection information table memory having connection information inside the convolutional encoder for each convolutional code, and a state transition having, as a state transition table, state transition information of an internal register of the convolutional encoder for generating the convolutional code A table memory, a decoder capable of decoding an arbitrary convolutional code by setting state transition information, and a signal selector for extracting a control signal indicating a frequency used for communication and a convolutional code from a received signal And a terminal controller for outputting a code switching signal and a frequency switching signal from a control signal output from the signal selector, and a code truncation output from the terminal controller. A code control signal generator that generates a code control signal for a convolutional encoder and a decoder based on a received signal, and a frequency control signal from a frequency switching signal output from a terminal station side controller to a transmitter and a receiver. And a frequency control signal generator for outputting, a specified frequency is set in a transmitter and a receiver by a control code sent from a base station, and a specified convolutional code is encoded. It has the effect that these frequencies and convolutional codes are used for communication.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the invention described in the convolutional encoder, a connection table memory in which a connection table holding connection information inside the convolutional encoder is stored, and an index signal indicating a convolutional code used for communication, An address generator for generating an address of a connection information table memory in which connection information of a specified convolutional code is recorded, a connection information register for holding connection information of a convolutional encoder, and reading from the connection table memory And an AND circuit for controlling the input of the input information bits to the adder, wherein the transmission information sequence has an arbitrary convolution. It has the effect of being encoded into a code.

The invention described in claim 5 is the second or third invention.
In the invention described in 1, the decoder stores a state transition table memory storing a state transition table holding all state transition information of codes that can be decoded, and stores a state transition of a convolutional code used for communication. And has the effect that the contents of the state transition register are rewritten to the state transition of the convolutional code specified by the convolutional code index signal.

According to a sixth aspect of the present invention, in the second aspect of the present invention, an error counter for counting errors generated during communication is provided, and the controller outputs the error counter output signal and the reception signal from the receiver. When the subsequent communication is started by updating the content of the usage record for the frequency used for communication and the convolution code based on the signal level, the convolution with the high use probability and the low error rate is used. The combination with the code is to be preferentially selected as the combination of the frequency and the code to be used for communication, and when starting communication, a frequency with a high use probability and a convolutional code with a low error rate are used. Has the effect that the combination of is selected.

According to a seventh aspect of the present invention, there is provided a digital radio communication system comprising a base station and a terminal station for performing radio communication between the base station and the terminal station and between the base stations. By transmitting and receiving a known information sequence between base stations and calculating a difference between the received signal sequence and the known signal sequence, a noise level occurrence probability distribution between the transmitting and receiving wireless stations is obtained, and the obtained noise level occurrence probability is obtained. The convolutional code having the lowest error rate with respect to the distribution is used for communication, and has the effect of reducing transmission path errors in communication around the base station.

An eighth aspect of the present invention is a digital radio communication system comprising a base station and a terminal station for performing radio communication between the base station and the terminal station and between the base stations. By transmitting and receiving a known information sequence between base stations and calculating a difference between the received signal sequence and the known signal sequence, a noise level occurrence probability distribution between the transmitting and receiving wireless stations is obtained, and the obtained noise level occurrence probability is obtained. As a convolutional code having the lowest error rate with respect to the distribution, a noise level occurrence probability distribution having a preselected feature and a noise level occurrence probability distribution having a preselected feature have the highest error correction capability. Using a table that stores the results of examining combinations with high convolutional codes, the pattern of the shape of the noise level occurrence probability distribution during transmission and reception and the noise level occurrence probability distribution with preselected features The optimum convolutional code for the highest noise level occurrence probability distribution of the correlation value obtained by the switching is selected, and the selected optimum convolutional code is used for communication. Is reduced.

According to a ninth aspect of the present invention, there is provided a digital radio communication system comprising a base station and a terminal station, and constituting a base station of a digital radio communication system for performing radio communication between the base station and the terminal station and between base stations. A wireless communication device, comprising: a convolutional encoder capable of generating an arbitrary convolutional code by setting internal connection information; and a connection information within the convolutional encoder for each convolutional code. A connection information table memory, a state transition table memory having, as a state transition table, state transition information of an internal register of a convolutional encoder that generates a convolutional code, and an arbitrary convolutional code by setting state transition information. A decoder capable of decoding, a signal selector for extracting a control signal indicating a frequency used for communication and a convolutional code from a received signal, and a set of a frequency and a convolutional code Frequency / code usage rate table memory storing frequency / code usage rate table in which usage frequency (usage rate) is recorded for each combination, and frequency and convolutional code used for communication are selected by frequency / code usage rate table Controller, a code control signal generator that outputs a code control signal to a convolutional encoder and a decoder according to a code switching signal output from the controller, and data and signals on a frequency / code usage rate table. A frequency control signal generator for outputting a frequency control signal to a transmitter and a receiver based on a frequency switching signal output from the controller based on a control signal output from the selector, and a frequency / convolution output from the controller A frequency / code switching signal generator for generating a frequency / code switching signal for the terminal station from the code control signal. Has the effect of utilization based on the utilization frequency and code utilization table is updated, a frequency to use for communication with the convolutional code is selected each time.

According to a tenth aspect of the present invention, there is provided a digital radio communication system comprising a base station and a terminal station, and constituting a terminal station of a digital radio communication system for performing radio communication between the base station and the terminal station and between the base stations. A wireless communication device, comprising: a convolutional encoder capable of generating an arbitrary convolutional code by setting internal connection information; and a connection information within the convolutional encoder for each convolutional code. A connection information table memory, a state transition table memory having, as a state transition table, state transition information of an internal register of a convolutional encoder that generates a convolutional code, and an arbitrary convolutional code by setting state transition information. A decoder capable of decoding, a signal selector for extracting a control signal indicating a frequency used for communication and a convolutional code from a received signal, and a signal selector for outputting a signal output from the signal selector. A terminal controller that outputs a code switching signal and a frequency switching signal from a control signal to be transmitted, and a code control signal to a convolutional encoder and a decoder by using a code switching signal output from the terminal station controller. And a code control signal generator for generating a code control signal generator and a frequency control signal generator for outputting a frequency control signal from a frequency switching signal output from the terminal station side controller to a transmitter and a receiver. The specified control code sets the specified frequency to the transmitter and the receiver, sets the specified convolutional code to the encoder and the decoder, and uses these frequencies and the convolutional code for communication. Having.

According to an eleventh aspect of the present invention, in the ninth or tenth aspect of the present invention, the convolutional encoder includes a connection table storing a connection table for holding connection information inside the convolutional encoder. A memory, an address generator for generating an address of a connection information table memory in which connection information of a specified convolution code is recorded by an index signal indicating a convolution code used for communication, and a convolution encoder A connection information register that holds the connection information of the above, a connection information register rewriter that writes the connection information read from the connection table memory into the connection information register, and an AND circuit that controls the input of the input information bits to the adder. And has the effect that the transmission information sequence is encoded into an arbitrary convolutional code.

According to a twelfth aspect of the present invention, in the ninth or tenth aspect of the present invention, the decoder has a state transition table memory for storing a state transition table holding all state transition information of codes that can be decoded. And a state transition register that stores state transitions of the convolutional code used for communication, wherein the content of the state transition register is the convolutional code specified by the convolutional code index signal. It has the effect of being rewritten as a state transition.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a block diagram showing a base station constituting a digital radio communication system according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a convolutional encoder that converts an input information bit sequence into a convolutional code bit sequence;
Reference numeral 2 denotes a connection information table memory for storing a connection information table holding connection information inside the convolutional encoder 1 for an arbitrary convolutional code; 3, a decoder for decoding a convolutional code used for communication; Is a state transition table memory that stores a state transition table that holds information (state transition information) on transition states of arbitrary convolutional codes that can be configured by the convolutional encoder 1, and 5 is output from the decoder 3. A signal selector for selecting a control code and an information sequence (information bit sequence input to the convolutional encoder 1) from a decoded received signal (hereinafter, referred to as “decoded received data”); Is a code control signal generator that outputs a convolutional code index signal indicating a convolutional code used for communication to the convolutional encoder 1 and the decoder 3, and 8 is a frequency input indicating a frequency used for communication. The transmitter 11 box signal, the receiver 1
2, a frequency control signal generator 9 for outputting an error counter for detecting an error in the decoded received data sequence and counting the number of errors, and 10 a frequency of use for each combination of frequency and convolutional code (use rate) ) Is recorded, and the recorded usage rate is updated by the controller 6 for each communication. A frequency / code usage rate table memory, 11 is a transmitter, 12 is a receiver, 13
Is a frequency / code switching signal generator for generating and outputting a frequency / convolution code switching signal for controlling the switching of the convolutional code used for communication and the frequency by the signal output from the controller 6, and 14 is a frequency / code switching signal Generator 1
A signal for stopping the input of transmission data to the convolutional encoder 1 and transmitting the frequency / convolutional code switching signal to the convolutional encoder 1 in order to transmit the three-output frequency / convolutional code switching signal It is a switch.

With respect to the base station configured as described above,
The function, operation, and the like will be described.

The convolutional encoder 1 converts the connection information stored in the connection information table memory 2 so as to generate the convolutional code specified by the convolutional code index signal from the code control signal generator 7. Convolutional encoder using 1
Change the internal configuration. Thereby, it is possible to configure any specified convolutional encoder. Decoder 3
Decodes the convolutional code specified by the convolutional code index signal from the code control signal generator 7,
The operation inside the decoder is switched according to the state transition information stored in the state transition table memory 4. Thereby, any designated convolutional code can be decoded. When the frequency / convolutional code switching control signal is output from the decoder 3, the signal selector 5 extracts the signal and outputs it to the controller 6. The controller 6 selects a convolutional code and a frequency used for communication based on the frequency / code usage rate table, and transmits a signal indicating the selected frequency and the convolutional code to a code control signal generator 7 and a frequency control signal generator. The signal is output to the signal generator 8. Further, the controller 6 uses the signal indicating the count result of the occurrence of an error in the received signal output from the error counter 9 and the signal indicating the reception level output from the receiver 12 to store the frequency / code usage table memory 10 Update the frequency / code usage rate table.

As described above, according to the present embodiment, a combination of a frequency having a high usage rate and a convolutional code is selected so as to be preferentially used for new communication, and the selected frequency and the convolutional code are selected. Can be used for communication by notifying the terminal station of the combination, so that the convolutional code and frequency used for communication can be switched to a combination with less error (higher use rate) in the previous communication. And transmission path error characteristics can be improved.

(Embodiment 2) FIG. 2 is a block diagram showing a terminal station constituting a digital radio communication system according to Embodiment 2 of the present invention. In FIG. 2, 1 is a convolutional encoder, 2 is a connection information table memory, 3 is a decoder, 4 is a state transition table memory, 5 is a signal selector, 7
Is a code control signal generator, 8 is a frequency control signal generator, 1
1 is a transmitter and 12 is a receiver, which are the same as those in FIG. 1 and are denoted by the same reference numerals and description thereof is omitted. 6a
Is a terminal-station-side controller, and the terminal-station-side controller 6a transmits a convolutional code used for communication transmitted from the base station and a signal indicating a frequency to a code control signal generator 7 and a frequency control signal generator 8 Output to The configuration of FIG. 2 is different from that of FIG. 1 in that an error counter 9, a frequency / code use rate table memory 10,
The point is that the configuration is such that the frequency / code switching signal generator 13 and the signal switching device 14 are omitted.

The functions and operations of the terminal station configured as described above are different from those of the base station of FIG. 1 only in the functions and operations of the terminal-side controller 6a, and the other operations are the same. It is. The functions and operations of the terminal station side controller 6a are as described above. That is, the receiver 12 wirelessly receives control information from the base station, and based on this control information, the terminal-side controller 6a switches between the frequency used for communication and the convolutional code.

As described above, according to the present embodiment, the terminal station can switch the frequency used for communication and the convolutional code to a combination having less errors by the control information from the base station. Transmission path error characteristics can be improved.

(Embodiment 3) FIG. 3 is a block diagram showing a convolutional encoder 1 of a base station and a terminal station constituting a digital radio communication system according to Embodiment 3 of the present invention. In FIG. 3, 15 is a 1-bit delay element (flip-flop), 16 and 17 are binary XOR circuits,
Reference numeral 18 denotes an AND circuit, 19 denotes a connection information register that holds internal connection information of the convolutional encoder 1, 20 denotes a connection information register rewriter, and 21 denotes a code for a configurable convolutional code of the convolutional encoder 1. A connection table memory 22 for holding connection information inside the converter, and 22 is an address generator.

The convolutional encoder 1 configured as described above
The function, operation, and the like of will be described. The delay element 15 and the adders 15 to 17 generate check bits of a convolutional code which is a systematic code. Based on the connection information of the convolutional encoder 1 set in the connection information register 19, the AND circuit 18 determines whether or not the input information bit string can be connected to each of the XOR circuits 16 and 17 (outputs the input information bit string to the XOR circuit 16). Or not). Connection information register 19
Is, when the value held in each register is “1”,
It means that the connection between the input information bit string and the XOR circuit 16 is connected. If the value held in each register is "0", it means that the connection is not connected. The address generator 22 stores connection information for each convolutional code, specifies an address for generating the convolutional code specified by the code index signal to the connection table memory 21, and A register designation signal for designating which connection information register 19 the connection information read from is output to the connection information register rewriter 20, and a code switching signal for switching the configuration of the convolutional encoder 1 is similarly connected. Output to the information register rewriter 20. The connection information register rewriter 20 is generated by rewriting the contents of the connection information register 19 specified by the register specification signal from the address generator 22 to the contents of the connection information output from the connection table memory 21. Switch the convolutional code.

As described above, according to the present embodiment, the contents of the connection information register 19 designated by the register designation signal are rewritten with the contents of the connection information from the connection table memory 21, so that the contents are generated. The convolutional code can be switched, so that any convolutional code can be generated.

(Embodiment 4) FIG. 4 is a block diagram showing a decoder 3 of a base station and a terminal station constituting a digital radio communication system according to Embodiment 4 of the present invention.
In FIG. 4, reference numeral 22a denotes a code selection address generator;
Is a state transition table memory that stores data (state transition information) relating to all state transitions of the decodable convolutional code, and 24 is a state transition of the code in order to decode the convolutional code selected by the code index signal. A rewritable state transition register for holding information, 25 a path selector for finding a surviving path for each symbol of the received signal,
26 is a metric calculator for calculating a metric for each signal point from the received signal, 27 is a path memory storing the surviving path for each state, 28 is a path metric memory storing the path metric of each state, 29 is This is a decoding result searcher that obtains a decoding result by performing an inverse search of the maximum likelihood path from the result of the path metric memory 28.

The functions, operations, and the like of the decoder 3 configured as described above will be described. The code selection address generator 22a generates an address in the state transition table memory 23 where the state transition information of the convolutional code specified by the code index signal is stored, and writes the contents of the state transition register 24. A code switching signal for changing is generated. The state transition register 24 controls the operation of the decoder 3 based on the held state transition information, and determines which convolutional code to decode. The path selector 25, the metric calculator 26, the path memory 27, the path metric memory 28, and the decoding result searcher 29 are components of the Viterbi decoder which is the maximum likelihood decoder of the convolutional code. Since the internal operation is performed along the state transition specified by the state transition register 24, the state transition register 24
By rewriting the contents of (2), the decoder 3 capable of decoding an arbitrary convolutional code can be configured.

Although the present embodiment has been described assuming that the decoder is individually constituted by each block, the present invention is also applicable to a case where the entire decoder is constituted by a microchip computer such as a digital signal processor as software. Is applicable.

As described above, according to the present embodiment, the contents of the state transition register 24 are rewritten by the code switching signal from the code selection address generator 22a. Can be changed.

(Embodiment 5) FIG. 5 shows the operation of a controller 6 based on the contents of a frequency / code use rate table memory 10 of a base station constituting a digital radio communication system according to Embodiment 5 of the present invention. It is a flowchart. First, before starting communication, the base station selects a frequency and a convolutional code to be used for communication.In this case, the combination of the frequency and the convolutional code uses a frequency / code usage rate table. The combination of the frequency / convolutional code with a high probability is selected according to the probability so as to be reused with a higher probability than the combination of the frequency / convolutional code with a low probability (S
1). If the frequency selected in step 1 is in use (S2), the frequency / code usage rate table is updated (S2).
3) Select a combination of a new frequency and a convolutional code again using the same rule. If not in use in step 2,
The frequency / code usage rate table is updated (S4), and the frequency and the convolutional code used for communication are notified to the terminal station (S4).
5) Start communication (S6). Error counter 9 or software counter (not shown) for bit errors during communication
After the communication of step 8 is completed, the frequency / code use rate table is updated using the result of step 7 (S9).

As a result of the above processing, the frequency / code usage rate becomes larger in each base station as the combination of the optimal frequency / convolutional code with less transmission path error for the location, and conversely, becomes less optimal. The combination of the frequency and the convolutional code which is not becomes a smaller value. Thus, for each base station, the probability of the combination of the optimal frequency with a small transmission path error and the convolutional code automatically increases each time it is updated. Therefore, if the combination of the frequency used for communication and the convolutional code is selected using the frequency / code usage rate table, it is possible to efficiently determine the frequency and the convolutional code with less transmission path errors, Transmission path errors can be reduced.

As described above, according to the present embodiment, using the frequency / code usage rate table, the combination of the frequency / convolutional code with a high probability is more effective than the combination of the frequency / convolutional code with a low probability. Since the re-use is performed with a high probability, the probability of the combination of the optimal frequency and the convolutional code can be automatically increased at each update. It is possible to determine efficiently and to reduce transmission path errors.

(Embodiment 6) FIG. 6A is a block diagram showing a transmitter as a code selector in a controller of a base station constituting a digital radio communication system according to Embodiment 6 of the present invention. (B) is a block diagram showing a receiving section as a code selecting section in a terminal station side controller of a terminal station constituting a digital radio communication system according to Embodiment 6 of the present invention. In FIG. 6, reference numeral 31 denotes a PN code sequence, a pattern signal generator for generating a known signal such as a repetition signal of a simple “0” or “1” signal, 32 denotes a transmitter,
3 is a transmitting antenna, 34 is a receiving antenna, 35 is a receiver for receiving a transmitted known signal, 36 is a signal comparator, 37 is a receiving unit that generates the same signal sequence as the pattern signal generator 31 of the transmitting unit. A signal generator 38; a noise occurrence probability calculator 38; a rewritable memory 39;
Is a pattern matching circuit, 41 is a code selector, 42 is a noise level generator that stores and holds a table with a pair of a noise level generation probability distribution having some characteristic and an optimal convolutional code that minimizes errors. It is a probability distribution versus optimal code table memory.

The function, operation, and the like of the code selector configured as described above will be described. Signal comparator 3
6 calculates a difference signal between the signal received by the receiver 35 and the signal generated by the pattern signal generator 37 that generates the same signal sequence as that of the pattern signal generator 31, and calculates the difference between the two obtained signals. A signal, that is, a noise detection result indicating a noise component included in an output signal of the receiver 35, and a phase control signal indicating a phase difference between the received signal from the receiver 35 and the signal generated by the pattern signal generator 37 Output. The pattern signal generator 37 is controlled by the phase control signal from the signal comparator 36 so that the phase difference from the received signal from the receiver 35 becomes zero. The noise occurrence probability calculator 38 calculates a noise level occurrence probability from the noise detection result output from the signal comparator 36. The memory 39 holds a noise level occurrence probability calculation result output from the noise level occurrence probability calculator 38 for each noise level. The pattern matching circuit 40 obtains a correlation value between the noise level occurrence probability distribution stored in the memory 39 and the noise level occurrence probability distribution stored in the optimal code table memory 42. The code selector 41 designates a convolutional code in the noise level occurrence probability distribution versus optimum code table memory 42, calls a noise level probability distribution in which the code can be the optimum code, and is observed and stored in the memory 39. The correlation value between the noise level occurrence probability distribution and the noise level occurrence probability distribution versus the noise level occurrence probability distribution called from the optimal code table memory 42 is obtained by the pattern matching circuit 40, so that the correlation value of the noise level occurrence probability distribution is the most. A large convolutional code is selected as a code selection result.

Although the present embodiment has been described assuming that the decoder is individually constituted by each block, the present invention is also applicable to a case where the entire decoder is constituted by software using a digital signal processor or the like. is there.

As described above, according to the present embodiment, the noise level occurrence probability distribution versus the optimum convolutional code which can be the specified convolutional code is called from the optimum code table memory 42, and the noise level observed and stored in the memory 39. The correlation value between the occurrence probability distribution and the noise level occurrence probability distribution called from the optimum code table memory 42 is obtained by the pattern matching circuit 40, and a code having the largest correlation value of the noise level occurrence probability distribution is selected as a code selection result. Therefore, it is possible to select an optimum code for the noise observed in the communication between the base stations.

(Embodiment 7) FIG. 7 is a configuration diagram showing a digital communication system according to Embodiment 7 of the present invention. In FIG. 7, a mobile terminal station within the communication range of the base station A1 performs communication using a frequency designated by the base station A1 and a convolutional code. In this case, when the base station A1 selects the combination of the frequency and the convolutional code, the base station A1
In the past communication performed by, the combination of the frequency and the convolutional code is selected in ascending order of the error rate, so that the communication error between the base station and the mobile terminal station is reduced. Further, with respect to adjacent base stations, in each base station, the usage rate for the combination of the frequency and the convolutional code stored in the frequency / code usage rate table memory is determined by the algorithm described in the fifth embodiment. in the base station differs by being updated coming to (adjacent with, by using the same frequency which is the frequency and convolutional code combined utilization of either the base station to become an interference wave is reduced Therefore, the effect of channel segregation can be obtained, and an increase in the error rate due to interference by adjacent base stations can be prevented. Embodiment 6
As shown in FIG. 7, the selection of the optimal code based on the transmission line noise measurement result is realized by transmitting and receiving a known signal sequence between each base station and measuring the statistical distribution of the transmission line noise. Is done.

As described above, according to the present embodiment, since the combination of the frequency and the convolutional code is selected in ascending order of the error rate in the past communication performed by the base station, the communication between the base station and the mobile terminal station is performed. Can be reduced.

(Eighth Embodiment) FIG. 8 is a sequence chart showing a frequency / convolutional code switching sequence between a base station and a terminal station according to an eighth embodiment of the present invention. Communication with a terminal station within the communication range of a certain base station is first started with a certain fixed frequency and a convolutional code. FIG.
When a communication start request is sent from the terminal station to the base station as shown in, the base station uses the frequency / code use rate table memory to store frequencies and codes that are not used for communication with other terminal stations at that time. , The combination of the frequency and code with the highest usage rate is selected. The base station notifies the terminal station of a frequency / code switching control signal indicating a combination of the selected frequency and code using a known frequency and code. The terminal station that has received the frequency / code switching control signal transmitted from the base station transmits the received frequency / code switching control signal to the base station using a known frequency and code.
The base station receiving the response signal from the terminal station determines whether or not the response signal matches the content of the signal previously transmitted as the frequency / code switching control signal, and if not, determines the frequency. Transmit the code switching control signal again, and repeat until the response from the terminal station matches. If there is no correct response even after the specified number of retransmissions, the communication is interrupted. If the response signal received by the base station matches the content of the previously transmitted frequency / code switching control signal, the base station transmits the frequency / code switching signal with a known frequency / code, and then transmits -Set the frequency of the receiver and the internal configuration of the encoder / decoder to the setting specified by the frequency / code switching control signal. The terminal station that has received the frequency / code switching signal sent from the base station specifies the frequency of the transmitter / receiver and the internal configuration of the encoder / decoder earlier by the frequency / code switching control signal. Set the frequency and sign. Thereafter, using the newly set frequency and code, a frequency / code switching end response is notified to the base station, the frequency / code switching setting is completed, and communication is started using the newly set frequency and code. .

As described above, according to the present embodiment, it is determined whether or not the signal responded by the base station matches the content of the signal previously transmitted as the frequency / code switching control signal. In this case, since the frequency / code switching control signal is transmitted again and repeated until the response from the terminal station matches, the optimum frequency and code can be set in the terminal station.

[0049]

As described above, according to the digital radio communication system of the present invention, the communication between the base station and the terminal station can be performed with the frequency and the code that minimize the transmission error.
An advantageous effect is obtained in that transmission path errors can be reduced and deterioration in communication quality can be reduced.

Further, the base station can select the frequency and the convolutional code used for communication based on the usage rate of the frequency / code usage rate table in which the usage rate is updated for each communication. A combination of a frequency having a high rate and a convolutional code can be selected so as to be preferentially used for new communication, and the advantageous effect that transmission path error characteristics can be improved can be obtained.

Further, in the terminal station, the frequency used for communication and the convolutional code can be switched by the control information from the base station, so that the advantageous effect that the transmission path error characteristic can be improved can be obtained. Can be

Further, the convolutional encoder holds a connection table memory for holding connection information, an address generator for generating an address of the connection information table memory based on an index signal, and holds connection information for the convolutional encoder. By providing a connection information register, a connection information register rewriter for writing connection information read from the connection table memory to the connection information register, and an AND circuit for controlling input of input information bits to the adder, An advantageous effect is obtained that the information bit sequence can be encoded into an arbitrary convolutional code.

Further, the decoder has a state transition table memory for holding all state transition information of codes that can be decoded,
By having a state transition register that stores state transitions of convolutional codes used for communication, the contents of the state transition registers can be rewritten to the state transitions of the convolutional code specified by the code index signal. Therefore, an advantageous effect that any convolutional code can be decoded can be obtained.

Further, the base station includes an error counter for counting errors generated during communication, and the controller
When the subsequent communication is started by updating the content of the usage record for the frequency and the convolutional code used for communication based on the output signal of the error counter and the level of the received signal from the receiver, By preferentially selecting a combination of a frequency with a high probability and a convolutional code with a low error rate as a combination of a frequency and a code used for communication,
When communication is started, an advantageous effect is obtained that a combination of a frequency having a high use probability and a convolutional code having a low error rate can be selected.

Further, the base station transmits and receives a known information sequence between the base stations, and obtains the difference between the received signal sequence and the known signal sequence to obtain a noise level occurrence probability distribution between the transmitting and receiving radio stations. The convolutional code that has the lowest error rate with respect to the obtained noise level occurrence probability distribution can be used for communication, and the advantageous effect that transmission line errors can be reduced in communication around the base station can be obtained. can get.

Further, the base station transmits and receives a known information sequence between the base stations, and obtains the difference between the received signal sequence and the known signal sequence to obtain a noise level occurrence probability distribution between the transmitting and receiving radio stations. As a convolutional code having the lowest error rate with respect to the obtained noise level occurrence probability distribution, the noise level occurrence probability distribution having a preselected characteristic and the noise of the noise level occurrence probability distribution having a preselected characteristic are obtained. Using a table that stores the results of examining the combination of convolutional codes with the highest error correction capability, the noise level occurrence probability distribution during transmission and reception and the noise level occurrence probability with preselected characteristics Select the optimal convolutional code for the noise level occurrence probability distribution with the highest correlation value obtained by pattern matching of the distribution and the shape, and use the selected optimal convolutional code for communication The Rukoto, advantageous effect is obtained that kills it possible to further reduce the transmission path error in the communication of the neighboring base stations.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a base station included in a digital wireless communication system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a terminal station constituting a digital wireless communication system according to a second embodiment of the present invention;

FIG. 3 is a block diagram showing a convolutional encoder of a base station and a terminal station constituting a digital radio communication system according to a third embodiment of the present invention;

FIG. 4 is a block diagram showing decoders of a base station and a terminal station which constitute a digital wireless communication system according to a fourth embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of a controller based on the contents of a frequency / code use rate table memory of a base station constituting a digital wireless communication system according to a fifth embodiment of the present invention.

FIG. 6 (a) is a block diagram showing a transmission unit as a code selection unit in a controller of a base station constituting a digital wireless communication system according to a sixth embodiment of the present invention; and (b) a sixth embodiment of the present invention. FIG. 1 is a block diagram showing a receiving unit as a code selecting unit in a terminal-side controller of a terminal station constituting a digital wireless communication system.

FIG. 7 is a configuration diagram showing a digital communication system according to a seventh embodiment of the present invention.

FIG. 8 is a sequence chart showing a frequency / convolutional code switching sequence between a base station and a terminal station according to Embodiment 8 of the present invention.

9A is a block diagram showing a transmitter constituting a digital radio communication device used in a conventional digital radio communication system. FIG. 9B is a block diagram showing a receiver constituting a digital radio communication device used in a conventional digital radio communication system. Block diagram showing

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Convolutional encoder 2 Connection information table memory 3 Decoder 4 State transition table memory 5 Signal selector 6 Controller 6a Terminal side controller 7 Code control signal generator 8 Frequency control signal generator 9 Error counter 10 Frequency / Code usage rate table memory 11, 32 Transmitter 12, 35 Receiver 13 Frequency / code switching signal generator 14 Signal switching device 15 Delay element 16, 17 XOR circuit 18 AND circuit 19 Connection information register 20 Connection information register rewriter 21 Connection table memory 22 Address generator 22a Code selection address generator 23 State transition table memory 24 State transition register 25 Path selector 26 Metric calculator 27 Path memory 28 Path metric memory 29 Decoding result searcher 31, 37 Pattern signal generator 33 For sending Antenna 34 receiving antenna 36 signal comparator 38 noise level probability calculator 39 memory 40 pattern matching circuit 41 code selector 42 noise level occurrence probability distribution versus optimum code table memory

Claims (12)

[Claims] 1. A digital wireless communication system comprising a base station and a terminal station for performing wireless communication between the base station and the terminal station and between the base stations, wherein the base station comprises: Selecting a combination of a frequency and a convolutional code that minimize the transmission error with respect to the noise around the station, notifying the selected combination to the terminal station, and selecting the frequency and the convolutional code of the selected combination. A digital wireless communication system that performs communication using the. 2. A convolutional encoder capable of generating an arbitrary convolutional code by setting internal connection information, and an internal convolutional encoder for each convolutional code. A connection information table memory having connection information, a state transition table memory having, as a state transition table, state transition information of an internal register of a convolutional encoder for generating the convolutional code, and setting the state transition information. A decoder capable of decoding an arbitrary convolutional code, a signal selector for extracting a control signal indicating a frequency used for communication and a convolutional code from a received signal, and a signal selector for each combination of a frequency and a convolutional code. A frequency / code use rate table memory for storing a frequency / code use rate table in which a use frequency (use rate) is recorded; and a frequency and a convolutional code used for communication. A controller selected by a wave number / code usage rate table, and a code control signal generator that outputs a code control signal to the convolutional encoder and the decoder by a code switching signal output from the controller, A frequency control signal that outputs a frequency control signal to a transmitter and a receiver by a frequency switching signal output from the controller based on the data on the frequency / code usage rate table and the control signal output from the signal selector. The digital radio communication according to claim 1, further comprising: a generator; and a frequency / code switching signal generator for generating a frequency / code switching signal for the terminal station from a frequency / convolutional code control signal output from the controller. system. 3. A convolutional encoder capable of generating an arbitrary convolutional code by setting internal connection information, and a terminal inside the convolutional encoder for each convolutional code. A connection information table memory having connection information, a state transition table memory having, as a state transition table, state transition information of an internal register of a convolutional encoder for generating the convolutional code, and setting the state transition information. A decoder capable of decoding any convolutional code, a signal selector for extracting a frequency used for communication and a control signal indicating the convolutional code from a received signal, and the control output from the signal selector A terminal-side controller that outputs a code switching signal and a frequency switching signal from the signal,
A code control signal generator that generates a code control signal for a convolutional encoder and a decoder according to a code switching signal output from the terminal station-side controller, and a frequency switch output from the terminal station-side controller The digital wireless communication system according to claim 1, further comprising a frequency control signal generator that outputs a frequency control signal from the signal to a transmitter and a receiver. 4. The convolutional encoder according to claim 1, further comprising a connection table memory storing a connection table for holding connection information inside the convolutional encoder, and an index signal indicating a convolutional code used for communication. An address generator for generating an address of the connection information table memory in which connection information of a specified convolutional code is recorded; a connection information register for holding connection information of the convolutional encoder; and the connection table. A connection information register rewriter for writing the connection information read from the memory into the connection information register, and an AND for controlling the input of the input information bits to the adder
The digital wireless communication system according to claim 2, further comprising a circuit. 5. A decoder according to claim 1, wherein said decoder stores a state transition table memory for storing all state transition information of codes that can be decoded, and a state transition of convolutional codes used for communication. 4. The digital wireless communication system according to claim 2, further comprising a state transition register. 6. An error counter for counting errors generated during communication, wherein said controller controls a frequency used for communication based on an output signal of said error counter and a signal level received from said receiver. When the subsequent communication is started by updating the contents of the usage record for the convolutional code and the convolutional code, the combination of the frequency with a high use probability and the convolutional code with a low error rate is 3. The digital wireless communication system according to claim 2, wherein the digital radio communication system is preferentially selected as a combination with a code. 7. A digital radio communication system comprising a base station and a terminal station, and performing radio communication between the base station and the terminal station and between the base stations, wherein the base station comprises the base station. A known information sequence is transmitted and received between the stations, and a noise level occurrence probability distribution between the transmitting and receiving radio stations is obtained by taking a difference between the received signal sequence and the known signal sequence. A digital radio communication system characterized by using a convolutional code having the lowest error rate with respect to distribution for communication. 8. A digital radio communication system comprising a base station and a terminal station for performing radio communication between the base station and the terminal station and between the base stations, wherein the base station comprises the base station. A known information sequence is transmitted and received between the stations, and a noise level occurrence probability distribution between the transmitting and receiving radio stations is obtained by taking a difference between the received signal sequence and the known signal sequence. As a convolutional code having the lowest error rate with respect to the distribution, a noise level occurrence probability distribution having a preselected feature and the noise correction capability of the noise of the noise level occurrence probability distribution having the preselected feature are best. Using a table storing the results of examining the combination with the convolutional code having a high probability, the noise level occurrence probability distribution between the transmitting and receiving radio stations and the noise level occurrence probability having the preselected characteristic The highest picked the best convolutional code to noise level generation probability distribution, a digital radio communication system, characterized by using the communication optimal convolutional codes in which the picked with the correlation value determined by pattern matching of the shape of the fabric. 9. A digital radio communication apparatus comprising a base station and a terminal station, and constituting the base station of a digital radio communication system for performing radio communication between the base station and the terminal station and between the base stations. A convolutional encoder capable of generating an arbitrary convolutional code by setting internal connection information, and connection information having connection information inside the convolutional encoder for each convolutional code. A table memory, a state transition table memory having, as a state transition table, state transition information of an internal register of a convolutional encoder that generates the convolutional code, and an arbitrary convolutional code by setting the state transition information. A decoder capable of decoding, a signal selector for extracting a control signal indicating a frequency used for communication and a convolutional code from a received signal, a frequency and a convolutional code The frequency of use of each combination (utilization)
A frequency / code usage table memory for storing a frequency / code usage rate table in which is recorded, a controller for selecting a frequency and a convolutional code used for communication from the frequency / code usage rate table, and the controller A code control signal generator that outputs a code control signal to the convolutional encoder and the decoder according to a code switching signal output from the controller, and data on the frequency / code use rate table and the signal selector. A frequency control signal generator that outputs a frequency control signal to a transmitter and a receiver according to a frequency switching signal output from the controller based on the output control signal, and a frequency / convolutional code output from the controller. A frequency / code switching signal generator for generating a frequency / code switching signal for the terminal station from a control signal. Digital wireless communication device. 10. A digital radio communication apparatus comprising a base station and a terminal station, and constituting said terminal station of a digital radio communication system for performing radio communication between said base station and said terminal station and between said base stations. A convolutional encoder capable of generating an arbitrary convolutional code by setting internal connection information, and connection information having connection information inside the convolutional encoder for each convolutional code. A table memory, a state transition table memory having, as a state transition table, state transition information of an internal register of a convolutional encoder that generates the convolutional code, and an arbitrary convolutional code by setting the state transition information. A decoder capable of decoding, a signal selector for extracting a control signal indicating a frequency and a convolutional code used for communication from the received signal,
A terminal-side controller that outputs a code switching signal and a frequency switching signal from the control signal output from the signal selector, and a convolutional encoder with a code switching signal output from the terminal-side controller. A code control signal generator that generates a code control signal for a decoder, and a frequency control signal generator that outputs a frequency control signal from a frequency switching signal output from the terminal station side controller to a transmitter and a receiver. A digital wireless communication device comprising: 11. A convolutional encoder comprising: a connection table memory in which a connection table holding connection information inside the convolutional encoder is stored; and an index signal indicating a convolutional code used for communication. An address generator for generating an address of the connection information table memory in which connection information of a specified convolutional code is recorded; a connection information register for holding connection information of the convolutional encoder; and the connection table. A connection information register rewriter for writing the connection information read from the memory into the connection information register, and an AN controlling input of input information bits to the adder
The digital wireless communication device according to claim 9, further comprising a D circuit. 12. The decoder according to claim 1, further comprising: a state transition table memory for storing a state transition table for holding all state transition information of the decodable code; and a state transition of a convolutional code used for communication. The digital wireless communication device according to claim 9, further comprising a state transition register.