JP2006279904A - Communication system, communication apparatus, communication method and communication control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system which is simplified and improved in communication quality. <P>SOLUTION: The present invention relates to a communication system wherein, in a transmitting apparatus, an iteration processing section 12 iterates iteration target data in at least part of communication data more than twice to produce processed communication data, a transmitting/receiving section 14 transmits the processed communication data, in a receiving apparatus, a transmitting/receiving section 14 receives the processed communication data, and a decoding section 17 decodes the iteration target data from the received processed communication data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication system including a transmission device and a reception device, a communication device, a communication method, and a communication control program.

  In communication systems, errors may occur in communication data due to noise or the like mixed during transmission of communication data. Therefore, it is necessary to detect and correct such data errors. In particular, when data such as voice is transmitted / received, real-time performance is important, and therefore, the process of resending data needs to be reduced as much as possible. Therefore, it is desired to realize a high error correction capability without retransmitting data.

In order to meet such demands, various error correction techniques have been proposed. For example, a technique for selecting an optimum method from a plurality of error control methods according to the type of communication service (see Patent Document 1), a technique for synthesizing a compensation signal with a previous frame and a subsequent frame of a target frame ( Patent Document 2).
JP-A-8-251140 JP 2003-249957 A

  However, the technique of Patent Document 1 requires a plurality of encoding units and decoding units according to a plurality of error control schemes. In the technique of Patent Document 2 described above, since processing is performed for each of the target frame, the previous frame, and the subsequent frame, a plurality of encoding units and decoding units are also required.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a communication system, a communication apparatus, a communication method, and a communication control program that are simple and have improved communication quality.

  A communication system according to the present invention for solving the above-described problem is a communication system including a transmission device and a reception device, and the transmission device transmits data to be repeated that is at least a part of communication data two or more times. Repetitive data generating means for repeatedly generating processed communication data; and transmitting means for transmitting the processed communication data; and the receiving device receiving means for receiving the transmitted processed communication data; Decoding means for decoding the data to be repeated based on the received processed communication data.

  Thereby, a communication system having a high error correction capability can be realized with a simple configuration.

  The communication system may further include a determination unit that determines a type of data to be communicated, and the repetitive data generation unit may perform repetitive processing according to a determination result by the determination unit.

  As a result, in a communication system capable of transmitting and receiving a plurality of types of data, such as voice data and IP data, for example, data that requires real-time property is repeatedly processed according to the type of data to be communicated. It is possible to implement control such as not performing repetitive processing for data that is not performed.

  In the communication system, the repetition data generation unit may determine the number of repetitions according to a data transmission capacity between the transmission device and the reception device.

  Thereby, for example, in a communication system in which bidirectional communication is possible and the data transmission capacity of the communication path differs depending on the direction between the communication devices, data transfer between the transmission side and the reception side such as VoIP (Voice over Internet Protocol) is performed. When performing communication using a communication method in which it is desirable that the speeds be equal, high error correction capability can be realized by efficiently using the communication path.

  Further, in the communication system, the transmission device further includes a bit rate changing unit that changes a bit rate of data to be communicated to reduce data to be communicated, and the repetitive data generation unit includes the bit rate. The data reduced by the changing means may be set as the data to be repeated, and the number of repetitions may be determined in accordance with the rate of data reduction by the bit rate changing means.

  Thus, for example, in a communication system that transmits and receives data that requires real-time performance, such as voice data, even if the data transmission capacity of the communication path is low, the bit rate of the voice data is reduced and repeated processing is performed. High error correction capability can be realized without changing the data transfer rate on the path.

  In the communication system, the decoding unit may decode the repetition target data by combining a plurality of repeated data included in the processed communication data and performing a soft decision.

  As a result, even when noise is mixed in when transmitting data, the original data can be accurately decoded.

  Further, the communication device according to the present invention repeats data to be repeated that is at least a part of communication data twice or more to generate processed communication data, and transmits to transmit the processed communication data Means.

  In addition, another communication device according to the present invention is based on reception means for receiving communication data and processed communication data generated by repeating the repetition target data included in the received communication data twice or more. And decoding means for decoding the data to be repeated.

  In addition, the communication method according to the present invention includes a step of generating processed communication data by repeating data to be repeated that is at least a part of communication data twice or more, a step of transmitting the processed communication data, Receiving the transmitted processed communication data; and decoding the repetition target data based on the received processed communication data.

  In addition, the communication control program according to the present invention generates a processed communication data by repeatedly processing data to be repeated, which is at least a part of the communication data, twice or more, and transmits the processed communication data to a computer. And executing the step.

  In addition, another communication control program according to the present invention includes a step of receiving communication data in a computer, and processing completed communication data generated by repeating the repetition target data included in the received communication data twice or more. And executing the step of decoding the data to be repeated.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the communication system according to the embodiment of the present invention includes a base station device 10, a mobile station device 20, and a communication network 30.

  The mobile station device 20 and the communication network 30 are configured to be able to communicate with each other via the base station device 10.

  The base station apparatus 10 and the mobile station apparatus 20 are both communication apparatuses having a wireless communication function, and are configured to be able to perform wireless communication with each other via an antenna provided in each. In this wireless communication, first, the transmission side communication device modulates communication data by a predetermined modulation method, and transmits the data as a wireless signal from the antenna. Then, the receiving-side communication device receives the radio signal arriving at the antenna, demodulates it by a demodulation method corresponding to a predetermined modulation method, and acquires original communication data. The base station device 10 and the mobile station device 20 function as a transmitting device and a receiving device, respectively, and perform such wireless communication with each other.

  Functionally, the base station apparatus 10 and the mobile station apparatus 20 according to the present embodiment have a coding unit 11, a repetition processing unit 12, a modulation unit 13, a transmission / reception unit 14, and a received signal acquisition unit, as shown in FIG. 15, a discrimination processing unit 16, and a decoding unit 17.

  When real data (for example, voice data or IP data) to be communicated is input, the encoding unit 11 determines the type and encodes the actual data according to the determination result. Specifically, first, when the input data is analog data such as audio data, a process of converting it into digital data is performed. Then, if necessary, processing such as data compression or encoding by a method such as convolutional code is performed, and data processed for each predetermined size is output.

  As a method for determining the type of data by the encoding unit 11, for example, there is a method in which a data generation unit (not shown) that outputs actual data to be communicated to the encoding unit 11 sends data type information to the encoding unit 11. . In addition, there is a method in which the determination processing unit 16 determines the type of data included in the signal received by the communication apparatus, the output of the result is received by the encoding unit 11, and the determination is made based on the output result. Alternatively, the bit rate of the data sent to the encoding unit 11 as a transmission target is compared with the bit rate of the data received by the communication device and decoded by the decoding unit 17, and both match within a predetermined range. In some cases, there is a method of determining the voice data.

  In addition, the size of the data output from the encoding unit 11 is determined by the number of repetitions in the iterative process executed later by the iterative processing unit 12. Specifically, when the size of data stored in a communication frame that is finally transmitted / received in the communication system is X, the size of data output from the encoding unit 11 is X when no repetition is performed. When the repetition is performed N times, the size of the data output from the encoding unit 11 is X / N.

  The iterative processing unit 12 generates processed communication data by repeating the digital data output from the encoding unit 11. For example, when N repetitions are performed, data in which N pieces of target data are arranged in order is generated.

  Here, as a method of determining the number of repetitions N, there is a method of determining according to the data transmission capacity of the communication system. For example, when the data transmission capacity when transmitting data from the mobile station apparatus 20 to the base station apparatus 10 is N times the data transmission capacity when transmitting data from the base station apparatus 10 to the mobile station apparatus 20, In data transmission from the station apparatus 20 to the base station apparatus 10, the repetition processing unit 12 generates data obtained by repeating communication target data N times. In this case, the data transmission rate of actual data sent from the base station device 10 to the mobile station device 20 matches the data transmission rate of actual data sent from the mobile station device 20 to the base station device 10.

  Or it is good also as changing the bit rate of the data used as communication object, and determining the frequency | count of repeating according to this change. Specifically, when the data to be communicated is audio data or the like, the bit rate of the data is changed to 1 / N. As a result, the data input to the encoding unit 11 is reduced to 1 / N before the bit rate is changed. On the other hand, the repetition processing unit 12 generates data obtained by repeating the communication target data N times. Thereby, the data repeated N times can be transmitted irrespective of the data transmission capacity between the base station apparatus 10 and the mobile station apparatus 20.

  Further, in this case, the number of repetitions may be changed according to the data error occurrence state. Specifically, when data retransmission due to data errors occurs frequently, the error correction capability is improved by increasing the number of repetitions, and when data retransmission due to data errors hardly occurs, iterative processing is not performed, Send the data as it is. This method may be combined with the method for determining the number of repetitions according to the data transmission capacity described above, and the number of repetitions may be determined according to the state of the communication line.

  The modulation unit 13 modulates the processed communication data generated by the repetition processing unit 12 or the communication data output from the encoding unit 11 into a signal that can be transmitted wirelessly. Here, as modulation methods, for example, BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), 8PSK (8 Phase Shift Keying, 8 Phase phase shift keying), 16QAM (16 Quadrature Amplitude Modulation), FSK (Frequency Shift Keying), ASK (Amplitude Shift Keying) You can use the method. Further, the modulation unit 13 outputs a communication frame in which a pilot signal is added to the modulated signal.

  Here, the structure of the communication frame output by the modulation unit 13 will be described with reference to FIG. When transmitting the communication data A of size X, the communication frame in the case where the repetitive processing is not performed has a structure in which a pilot signal is added to the head of the communication data A as shown in FIG. On the other hand, when the communication data A is repeatedly transmitted N times, the data to be transmitted is configured as N communication frames as shown in FIG. Each frame is a frame obtained by adding a pilot signal to data obtained by repeating N times of data A1, A2,... AN obtained by dividing communication data A into N pieces.

  The transmission / reception unit 14 transmits the communication frame output from the modulation unit 13 to the reception side device via the antenna. On the other hand, in the reception side device, the transmission / reception unit 14 receives a signal from the antenna and outputs the signal to the reception signal acquisition unit 15.

  The reception signal acquisition unit 15 extracts a signal transmitted from the transmission side device included in the signal received from the transmission / reception unit 14. In addition, when the receiving-side apparatus receives data using a plurality of antennas (adaptive array antennas), a process of combining a plurality of signals received from the transmission / reception unit 14 corresponding to the plurality of antennas is performed.

  The discrimination processing unit 16 determines the type of communication data such as whether the communication data transmitted by the received signal obtained by the received signal acquisition unit 15 is voice data or IP data. Further, the determination processing unit 16 may output determination result information to the encoding unit 11 and the decoding processing unit 17b, and may be used for processing for determining encoding and decoding methods and the like.

  As a method for determining the type of communication data, for example, there is a method in which an identification code is included in a pilot signal added by the modulation unit 13 and the identification code is read and determined. In addition, when establishing a connection between communication devices at the beginning of a series of data communication, information on the type of communication data is transmitted, and subsequent communication data is automatically determined to be that type of data. Also good.

  The decoding unit 17 includes an iterative combining unit 17a and a decoding processing unit 17b. In accordance with the determination result performed by the determination processing unit 16, the decoding unit 17 directly performs the decoding by the decoding processing unit 17b on the received signal that has not been iteratively processed. For a received signal that has been subjected to repetition processing, first, processing for combining signals repeated by the repetition combining unit 17a is performed, and then the signal combined by the repetition combining unit 17a is decoded by the decoding processing unit 17b.

  The iterative combining unit 17a divides the received signal repeated N times into N signals to be repeated, and combines the N signals corresponding to the original data to be repeated. To do. Then, a signal obtained by the synthesis is output to the decoding processing unit 17b.

  A specific example of this synthesis method will be described. For example, when the phase modulation method is used in the modulation unit 13, the following synthesis method can be used. That is, the iterative combining unit 17a determines signal points that represent N signal points on the IQ plane corresponding to the divided N received signals. Then, a signal indicated by the determined representative signal point is output to the decoding processing unit 17b.

  The iterative combining unit 17a can use, for example, a point that is the center of gravity of N signal points as a representative signal point. Specifically, N signal points on the IQ plane are added for each of the in-phase component and the quadrature component. Then, each value obtained by the addition is divided by N to obtain each average value. A signal point having each average value as an in-phase component and a quadrature component is a representative signal point.

  Alternatively, a representative signal point can be determined by performing multivariate analysis on the data of N signal points. Further, when determining representative signal points, it is not necessary to use all N signal points. For example, a representative signal point may be determined by excluding a signal point far away from other signal points.

  The decoding processing unit 17b demodulates and decodes the received signal or the signal obtained by repeatedly combining the received signal by the combining unit 17a, and outputs the result as received data.

  As a decoding method, for example, a soft decision decoding method such as maximum likelihood decision decoding can be used. In particular, when encoding by the convolutional code is performed in the encoding unit 11, the decoding can be performed by a method such as Viterbi decoding.

  In the decryption unit 17, the decryption may be performed first by the decryption processing unit 17b, and then iterative data may be synthesized by the iterative synthesis unit 17a. In this case, the decoding processing unit 17b decodes the received signal into digital data by a method such as hard decision decoding, and the iterative combining unit 17a uses the average value of each bit for the data included in the decoding process. The original data is restored by calculating

  Hereinafter, the flow of processing when data is actually transmitted and received using the communication apparatus according to the present embodiment will be described. In the following description, base station apparatus 10 and mobile station apparatus 20 are intended to communicate voice data and IP data. However, data that can be communicated in the communication system according to the present embodiment is these. Not limited to those. In the following description, the mobile station device 20 is described as a transmission side device and the base station device 10 is a reception side device. However, even if the transmission side and the reception side are interchanged, the processing of the communication system according to the present embodiment is performed. It is the same.

  FIG. 4 is a flowchart showing a flow of transmission processing performed in the mobile station apparatus 20. In the mobile station device 20, the encoding unit 11 first determines whether the type of data to be communicated is voice data or IP data (S101).

  If the communication target data is audio data as a result of the determination in S101, the encoding unit 11 encodes the audio data and divides the communication data into X / N sizes according to the number of repetitions N times. And output (S102). Here, the data transmission capacity when data is transmitted from the mobile station apparatus 20 to the base station apparatus 10 is three times the data transmission capacity when data is transmitted from the base station apparatus 10 to the mobile station apparatus 20. To do. Therefore, as for audio data, communication data that is normally transmitted in one communication frame is divided into three pieces of data of 1/3 size and output. Next, the repetition processing unit 12 generates data obtained by repeating the encoded data output in S102 three times each (S103). The generated processed data is output to the modulation unit 13 in order.

  On the other hand, if the result of determination in S101 is that the data to be communicated is IP data, the encoding unit 11 simply performs encoding and outputs communication data of size X to the modulation unit 13 (S104).

  The modulator 13 modulates the data output in S103 or S104, and adds a pilot signal (S105). Here, it is assumed that the pilot signal includes an identification code for identifying the data type. The signal generated in S105 is transmitted by the transmission / reception unit 14 via the antenna.

  The signal transmitted by the mobile station device 20 is received by the base station device 10. FIG. 5 is a flowchart showing a flow of reception processing performed in the base station apparatus 10. In the base station apparatus 10, first, the transmission / reception unit 14 receives a signal reaching the antenna. And the received signal acquisition part 15 extracts the signal transmitted from the mobile station apparatus 20 from the received signal as a received signal (S201).

  Next, the determination processing unit 16 determines the type of communication data included in the received signal (S202). The determination is made based on the identification code included in the pilot signal.

  As a result of the determination in S202, if it is determined as audio data, the received communication frame includes a signal repeated three times, so the repeated signal is divided into three. Then, a process of synthesizing three signals is performed on the signal corresponding to each bit of the original data included in the divided signal (S203). On the other hand, when it is determined as IP data as a result of the determination in S202, the repeated synthesis process is not performed, and the determined signal is output to the decoding processing unit 17b as it is.

  The decoding processing unit 17b performs demodulation and decoding processing on the signal repeatedly synthesized by the synthesizing unit 17a when determined as voice data in S202 and on the signal output as it is when determined as IP data. Perform (S204). The decoding processing unit 17b decodes the original communication data by a method corresponding to the modulation processing performed in S105 and the encoding processing performed in S102 or S103.

  Through the series of processes described above, the communication system according to the present embodiment transmits data after repeatedly processing audio data and IP data according to the data type and the data transmission capacity of the communication line. Can do. As a result, particularly in the case of data requiring real-time properties, even if there is a data error in the received data, the original data can be decoded with high accuracy, and the data retransmission processing can be reduced.

  In addition, the above processing can be realized by a program held in a storage unit (not shown) installed in a communication device even in a communication system that uses only a single encoding method and decoding method. Thus, it is possible to improve the error correction capability of the communication system without incorporating a simple encoding method.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the mobile communication system has been described as an example, but the present invention can be applied even if another communication method such as a wired communication system is used.

1 is a diagram showing an overall configuration of a communication system according to an embodiment of the present invention. It is a functional block diagram which shows an example of the communication apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the communication frame transmitted with the communication system which concerns on embodiment of this invention. It is a flowchart which shows an example of the data transmission process performed by the communication apparatus which concerns on embodiment of this invention. It is a flowchart which shows an example of the data reception process performed by the communication apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Base station apparatus, 20 Mobile station apparatus, 30 Communication network, 11 Encoding part, 12 Repetition processing part, 13 Modulation part, 14 Transmission / reception part, 15 Received signal acquisition part, 16 Discrimination processing part, 17 Decoding part, 17a Repetitive synthesis part 17b Decoding processing unit.

Claims (10)

In a communication system including a transmission device and a reception device,
The transmitter is
Repetitive data generating means for generating the processed communication data by repeating the data to be repeated, which is at least a part of the communication data, twice or more;
Transmitting means for transmitting the processed communication data;
Including
The receiving device is:
Receiving means for receiving the transmitted processed communication data;
Decoding means for decoding the repetition target data based on the received processed communication data;
A communication system comprising: The communication system according to claim 1,
A determination unit for determining a type of data to be communicated;
The repetitive data generation means executes a repetitive process according to a result of determination by the determination means. The communication system according to claim 1 or 2,
The repetitive data generation means determines the number of repetitions according to the data transmission capacity between the transmitting device and the receiving device. The communication system according to any one of claims 1 to 3,
The transmission device further includes bit rate changing means for changing the bit rate of data to be communicated to reduce the data to be communicated,
The repetitive data generating means uses the data reduced by the bit rate changing means as data to be repeated, and determines the number of repetitions according to the rate of data reduction by the bit rate changing means. The communication system according to any one of claims 1 to 4,
The said decoding means synthesize | combines the several repeated data contained in the said processed communication data, and decodes the said repetition object data by performing a soft decision. Repetitive data generating means for generating the processed communication data by repeating the data to be repeated, which is at least a part of the communication data, twice or more;
Transmitting means for transmitting the processed communication data;
A communication device comprising: Receiving means for receiving communication data;
Decoding means for decoding the repetition target data based on the processed communication data generated by repeating the repetition target data included in the received communication data twice or more;
A communication device comprising: Generating the processed communication data by repeating the data to be repeated, which is at least a part of the communication data, twice or more;
Transmitting the processed communication data;
Receiving the transmitted processed communication data;
Decoding the repetition target data based on the received processed communication data;
A communication method comprising: On the computer,
Generating the processed communication data by repeating the data to be repeated, which is at least a part of the communication data, twice or more;
Transmitting the processed communication data;
The communication control program characterized by performing this. On the computer,
Receiving communication data; and
Decoding the repetition target data based on the processed communication data generated by repeating the repetition target data included in the received communication data twice or more;
The communication control program characterized by performing this.

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