JP4637769B2 - Communication device - Google Patents

Description

  The present invention relates to a communication apparatus, and more particularly to acquisition of error occurrence information that can appropriately evaluate the quality of a communication path.

  One index for evaluating the performance of a communication system is error occurrence information indicating how much error has occurred in a communication path. There are various types of error occurrence information. One of the error occurrence rates is an error occurrence rate of 1 bit or more in a communication path among a plurality of unit data (such as time slots and packets) sequentially received by a receiving apparatus. Expressed by the percentage of errors.

Patent Document 1 describes a technique relating to measuring a BER (Bit Error Rate) indicating an error occurrence rate in bit units. Patent Document 2 describes a technique related to detecting a determination error of a binary signal.
JP 2005-269240 A JP 2005-223626 A

  By the way, the data receiving apparatus corrects an error occurring in the communication path by a predetermined error correction process (for example, an error correction process using a cyclic redundancy code). Then, the ratio of unit data that still contains an error of 1 bit or more after this correction is calculated as the error occurrence rate.

  However, when the error occurrence rate is calculated in this way, the unit data whose error has been corrected by the error correction processing is calculated as having no error, so that the quality of the communication path is appropriately adjusted based on the error occurrence rate. The problem arises that it cannot be evaluated.

  This problem will be described with a specific example. For example, in a communication system using a 4-bit error correction process, an error of up to 4 bits is corrected. On the other hand, for example, in a communication system using a 2-bit error correction process, only an error of up to 2 bits is corrected. For this reason, even if the quality (error occurrence status) of the communication path is the same, the error occurrence rate of the communication system using the 2-bit error correction processing is the communication system using the 4-bit error correction processing. Will be bigger than that. That is, the quality of the communication path cannot be appropriately evaluated based on the error occurrence rate.

  In this regard, it is also conceivable that unit data whose error has been corrected in the error correction process is handled as unit data including an error in calculating the error occurrence rate. However, if it is determined whether or not an error has been corrected by error correction processing for each unit data, there is a problem that the processing of the error correction processing program becomes heavy and is not realistic.

  Accordingly, an object of the present invention is to provide a communication apparatus that can acquire error occurrence information that can appropriately evaluate the quality of a communication path without increasing the processing of an error correction processing program.

  A communication apparatus according to the present invention for solving the above-described problems is output by a receiving unit that receives data, an error setting unit that erroneously outputs data received by the receiving unit, and the error setting unit. For data, error correction processing means for performing error correction processing, and data having an uncorrectable error in error correction by the error correction processing means is defined as error data, and error data is included in data received by the receiving means Error occurrence information acquisition means for acquiring error occurrence information indicating the degree of error.

  According to this, since the data is forcibly mistaken before the error correction process, the correction capability of the error correction process can be reduced. For example, when the correction capability of the error correction process is 2 bits, if the unit data is erroneously 2 bits, the correction capability is substantially 0 bits. For this reason, error occurrence information that can appropriately evaluate the quality of the communication path can be acquired without increasing the processing of the error correction processing program.

  In the communication apparatus, the error setting unit inverts a predetermined number of bits among a plurality of bits constituting the data received by the receiving unit according to the error correction capability of the error correction processing unit. Thus, the data received by the receiving means may be misleading.

  According to this, data can be erroneously caused by inversion of a predetermined number of bits.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a system configuration of a communication system 1 and functional blocks of a communication device 10 according to the present embodiment.

  The communication system 1 is a mobile communication system, for example. The communication system 1 includes a wireless communication path 2, and the communication devices 10 perform wireless communication with each other via the wireless communication path 2. In the following description, in this wireless communication, data transmission / reception is performed in units of time slots.

  Each communication device 10 is a computer including a CPU and a memory. The CPU is a processing unit for executing a program stored in a memory, and performs processing for controlling each unit of the communication device 10 and implements functions described later. The memory stores programs and data for carrying out the present embodiment. It also operates as a work memory for the CPU.

  An error may occur in a radio signal transmitted and received through the wireless communication path 2. Each communication device 10 performs an error correction process for correcting an error in data (unit data) included in a time slot received as a radio signal. Specifically, error correction processing is performed using an error correction algorithm such as a Hamming code, a cyclic redundancy code, or a convolutional code.

  Hereinafter, the function of the communication device 10-1 that receives the time slot wirelessly transmitted by the communication device 10-2 will be described with reference to functional blocks.

  As shown in FIG. 1, the communication device 10-1 includes a receiving unit 11, an input unit 20, an error setting unit 30, an error correction detection unit 40-1, an error correction detection unit 40-2, an error occurrence information acquisition unit 50, A processing unit 60 is included.

  The receiving unit 11 sequentially receives and demodulates time slots wirelessly transmitted sequentially by the communication device 10-2, acquires a bit string (unit data bit string) of unit data, and sequentially outputs it to the input unit 20.

  The input unit 20 sequentially receives input of unit data bit strings from the receiving unit 11 and sequentially outputs the received unit data bit strings to the error correction detection unit 40-2 and the error setting unit 30, respectively.

  The error setting unit 30 sequentially misplaces the unit data bit strings sequentially input from the input unit 20. Specifically, a predetermined number of the plurality of bits constituting the unit data bit string is inverted. More specifically, the number of bits corresponding to the error correction capability of an error correction detection unit 40-1 described later is inverted. More specifically, if the error correction capability is n bits, it is preferable to invert the number of bits (for example, n × 0.2) obtained by multiplying n bits by a predetermined ratio. . For example, if the error correction capability of the error correction processing performed by the error correction detection unit 40-1 is 20 bits and the predetermined ratio is 20%, 20 × 0.2 = 4 bits are inverted. If the error correction capability of the error correction processing performed by the error correction detection unit 40-1 is 20 bits and the predetermined ratio is 100%, 20 × 1 = 20 bits are inverted.

  Specifically, the processing relating to this inversion is performed using scramble data. That is, the error setting unit 30 is a bit string having the same length as the unit data bit string to be input, the bit value of the number of bits to be inverted is 1 and the bit string of which the value of the other bits is 0 ( Scrambled data). The error setting unit 30 inverts a predetermined number of bits in the unit data bit string by performing an exclusive OR operation (scramble process) on the scrambled data and the input unit data bit string, and converts the result into the result. Output to the error correction detector 40-1.

  The error correction detection unit 40-1 sequentially performs error correction for each of the unit data bit strings sequentially input from the error setting unit 30 by a predetermined error correction process, and an error is detected even after the error correction process is performed. Determine if it remains. Then, error remaining presence / absence information indicating whether or not an error remains in the unit data bit string obtained as a result of the error correction processing is acquired and sequentially output to the error occurrence information acquiring unit 50.

  The error correction detection unit 40-2 sequentially performs error correction on each of the unit data bit strings sequentially input from the input unit 20 by a predetermined error correction process, and an error remains after the error correction process is performed. It is determined whether or not.

  When no error remains in the unit data bit string obtained as a result of the error correction process, the error correction detection unit 40-2 outputs the unit data bit string to the processing unit 60. The processing unit 60 performs predetermined communication processing based on the unit data bit string output from the error correction detection unit 40-2. On the other hand, when an error remains in the unit data bit string obtained as a result of the error correction process, the error correction detection unit 40-2 discards the unit data bit string and uses the transmission unit (not shown) to transmit the communication device 10- 2 transmits a retransmission request.

  The error occurrence information acquisition unit 50 converts the unit data bit string having an uncorrectable error in the error correction by the error correction detection unit 40-1 based on the error remaining presence / absence information output from the error correction detection unit 40 to error unit data. Error occurrence information indicating the degree to which an error unit data bit string is included in the unit data bit string sequentially received by the receiving unit 11 is obtained as a bit string. More specifically, the ratio of the error unit data bit string to the unit data bit string received within a predetermined period is calculated and used as the error occurrence rate. The error occurrence information acquisition unit 50 periodically acquires the error occurrence information by periodically repeating the above processing, and stores it in the memory.

  The processing of the communication device 10-1 described above will be described again in detail with reference to the processing flowchart.

  FIG. 2 is a diagram illustrating a processing flow of the communication device 10-1. As shown in the figure, the communication device 10-1 acquires scrambled data including bit 1 of a predetermined ratio of error correction capability (S1). Then, the unit data bit string is scrambled by the obtained scramble data (S2). Subsequently, the error correction detection unit 40 performs error correction (S3), and as a result, error remaining presence / absence information is obtained (S4). And error occurrence information is acquired based on this error remaining presence information.

  Next, FIG. 3 is a diagram illustrating a processing flow of the communication device 10-1 when link adaptation is performed using the acquired error occurrence information. In the case shown in this figure, the communication device 10-1 appropriately changes the modulation method used in the communication performed with the communication device 10-2 according to the error occurrence information. Specifically, when it is determined that the error unit data bit string is relatively included in the error occurrence information, the modulation method is changed to a modulation method having a low multilevel (for example, 16QAM (4 multilevel). (Quadrature Amplitude Modulation) is changed to QPSK (Quadrature Phase Shift Keying) with multi-level 2 bits.) Although the communication rate is low, errors are not likely to occur. To. On the other hand, when it is determined that the error unit data bit string is contained to a relatively small extent based on the error occurrence information, the modulation method is changed to a high-level modulation method (for example, changed from QPSK to 16QAM), and high speed. Enable communication.

  Hereinafter, a description will be given with reference to FIG. As shown in the figure, the communication device 10-1 acquires the error rate (S10), acquires the relationship between the error rate R and the predetermined values A and B (A <B), and the result Accordingly, the multivalue level of communication is changed (S11, S12, S15, S16).

  Specifically, when B ≦ R, the multilevel value is lowered (S12), and the modulation method is changed to a slower modulation method (S13). Further, it is displayed to the user that the communication state has deteriorated (S14).

  If A ≦ R <B, the multivalue level is not changed (S15).

  If R <A, the multi-value level is increased (S16), and a change to a higher-speed modulation method is performed (S17). Furthermore, the fact that the communication state has improved is displayed to the user (S18).

  As described above, since the communication device 10-1 forcibly misregisters the unit data before the error correction process, the correction capability of the error correction process can be reduced. For this reason, error occurrence information that can appropriately evaluate the quality of the communication path can be acquired without increasing the processing of the error correction processing program.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, only one combination of the error setting unit 30 and the error correction detection unit 40 is provided, but a plurality of combinations may be provided. That is, the input unit 20 inputs unit data bit strings to the plurality of error setting units 30, and the error occurrence information acquisition unit 50 outputs the presence / absence of residual errors output from the error correction detection unit 40 corresponding to each error setting unit 30. Error occurrence information may be acquired for each error setting unit 30 based on the information. In the plurality of error setting units 30 thus provided, for example, when the three error setting units 30 are provided, the predetermined ratios are different from each other, such as 20%, 40%, and 60%, respectively. It is good as well. In this way, a plurality of types of error occurrence information can be obtained for one communication, so that more accurate error occurrence information can be obtained.

  In the above-described embodiment, the data transmission / reception is performed in units of time slots. However, for example, data transmission / reception may be performed in units of packets. In this case, the data included in the packet is unit data.

  Furthermore, the present invention is particularly useful when applied to wireless communication that is prone to errors in the communication path, but of course can also be applied to wired communication.

It is a figure which shows the system configuration | structure of the communication system which concerns on embodiment of this invention, and the functional block of a communication apparatus. It is a figure which shows the processing flow of the communication apparatus which concerns on embodiment of this invention. It is a figure which shows the processing flow of the communication apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Communication system, 2 Wireless communication paths, 10 Communication apparatus, 11 Reception part, 20 Input part, 30 Error setting part, 40 Error correction detection part, 50 Error occurrence information acquisition part, 60 Processing part

Claims (2)

Receiving means for receiving data;
Error setting means for erroneously outputting the data received by the receiving means;
Error correction processing means for performing error correction processing on the data output by the error setting means;
Error occurrence information acquisition for obtaining error occurrence information indicating the extent to which error data is included in the data received by the receiving means, as error data, in which there was an uncorrectable error in error correction by the error correction processing means Means,
A communication device comprising: The communication device according to claim 1,
The error setting means, by inverting a predetermined number of bits among a plurality of bits constituting the data received by the receiving means according to the error correction capability of the error correction processing means, Misleading received data,
A communication device.

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