JP2010124260A - Crc erroneous discrimination detection method and crc erroneous discrimination detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect CRC erroneous discrimination, and to improve error detection accuracy in a transmission path. <P>SOLUTION: A memory portion 12 sequentially memorizes the CRC code of the last transmission data. A code adding portion 13 transmits a transmission packet in which the CRC code of the transmission data is added in a position within a packet determined by the value of the memorized CRC code. A memory portion 15 memorizes data in the position within the packet determined by the value of the CRC code of the last reception packet. An error inspection portion 14 performs CRC error inspection about the reception packet with the memorized data. If a CRC error is detected, a search portion 16 sequentially repeats the CRC error inspection making the data in the plurality of positions within the packet previously determined in the reception packet as the CRC code, and if it becomes OK, the CRC error inspection about the last reception packet is made to be an erroneous discrimination. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a CRC (Cyclic Redundancy Check) erroneous determination detection method and a CRC erroneous determination detection device.

  Conventionally, as shown in FIG. 9, error check of transmission data is performed by dividing a transmission data by a predetermined generation polynomial in a CRC code generation unit 91 on the transmission side and a remainder (CRC) in a CRC code addition unit 92. Code) is added to the transmission data and transmitted. On the other hand, the CRC error checker 93 performs division using the same generator polynomial as that on the transmission side. If there is no remainder, the data is correct. It is determined that there was a data transmission error. In addition, as shown in FIG. 10, the CRC code is generally added to the end of all packet data (not related to the literature known invention).

  In addition, a method has been proposed in which the previous serial data sequence and the current serial data sequence (possible before and after the previous time) are multiplexed in one frame and a CRC code is added to each frame (for example, Patent Document 1). reference).

Japanese Patent Laid-Open No. 10-84334 (page 2 to page 3, FIG. 2)

  In the conventional error checking method described above, since the data transmission is redundant, the transmission efficiency is naturally low. When the CRC check of a certain frame is NG, the transmission data is obtained by applying another frame transmitted redundantly. Although the error can be remedied, there is a possibility that the wrong serial data is applied when the CRC is erroneously determined. That is, if an error occurs in both the data and the CRC code on the transmission line, and the result of division by the generator polynomial on the receiving side is zero, error detection cannot be performed, and the data and CRC code are transmitted correctly. It will be misjudged.

  Furthermore, since there is no means for detecting that an erroneous determination has been made, a silent alarm is generated. The probability of erroneous determination when an error occurs in both the data and the CRC code depends on the bit length of the CRC code. For example, if the CRC code is 8 bits, the probability is 2 (−8) power = approximately 4/1000. This probability seems to be low at first glance, but in the case of a huge amount of burst data, the error is perceived.

  Therefore, the present invention solves the above-described problems, and a CRC error determination detection method and a CRC error detection method that can detect a CRC error determination when the result of division by a generator polynomial for erroneous data and CRC on the transmission line is zero. It is an object of the present invention to provide a determination / detection device and improve error detection accuracy in a transmission path.

  In the CRC misjudgment detection method according to claim 1, the transmission side transmits a transmission packet in which the CRC code of the transmission data is added to the position in the packet determined by the CRC code value of the immediately previous transmission data, and on the reception side, When the CRC error check is performed by moving the data in the packet position determined by the CRC code value of the immediately previous received packet to the original CRC position, and CRC error is detected, the data at a plurality of predetermined packet positions in the received packet are detected. If the CRC error check is performed sequentially with the data as a CRC code, and no CRC error is detected, the previous received packet has no loss and there is no CRC error. If a CRC error is detected even after error checking, CR Characterized by an error.

  In the CRC misjudgment detection method according to claim 2, the transmitting side generates a CRC code for transmission data, a procedure for sequentially storing a CRC code generated for at least immediately preceding transmission data, and the transmission There is a procedure for transmitting a transmission packet added to a position in the packet determined by the value of the CRC code generated for the transmission data immediately before storing the CRC code of the data.

  On the other hand, the receiving side stores at least data at a position in the packet determined by the CRC code value of the immediately preceding received packet, and performs a CRC error check on the received packet by moving the stored data to the original CRC position. If a CRC error is detected as a result of the CRC error check, a procedure for sequentially repeating the CRC error check using data at a plurality of predetermined positions in the received packet as CRC codes, and while repeating the CRC error check If no CRC error is detected, if there is no loss and there is no CRC error for the previous received packet, the CRC error check is erroneously determined, and the CRC error is detected even after repeated CRC error checks. And a procedure for making a CRC error for the received packet. To.

  The CRC misjudgment detection method according to claim 3 is characterized in that, in the CRC misjudgment detection method according to claims 1-2, the position in the packet is determined by the lower n bits of the CRC code.

  The CRC misjudgment detection method according to claim 4 is the CRC misjudgment detection method according to claims 1 to 3, wherein the original CRC position is the end of the packet.

  The CRC misjudgment detection apparatus according to claim 5, wherein the transmitting side sequentially generates a CRC code generation unit that generates a CRC code for transmission data and a CRC code generated for at least the immediately preceding transmission data. A storage unit and a CRC code adding unit that transmits a transmission packet added to a position in the packet determined by the value of the CRC code generated for the transmission data immediately before storing the CRC code of the transmission data.

  On the other hand, the receiving side moves the stored data to the original CRC position and stores CRC data in the packet position determined by at least the CRC code value of the immediately preceding received packet. When a CRC error is detected as a result of the CRC error check and the CRC code error check unit that performs the CRC error check, the CRC error check is sequentially repeated with the data at a plurality of predetermined positions in the received packet as CRC codes. If no CRC error is detected, the CRC code for the immediately preceding received packet is a CRC error check if there is no packet loss and there is no CRC error, and if a CRC error is detected, the CRC code is set as a CRC error for the received packet. It has a position search part

[Action]
In the error detection method of the present invention, the CRC code generation unit on the transmission side divides transmission data by a predetermined generation polynomial, and transmits the remainder (CRC code) to the CRC code storage unit and the CRC code addition unit. The CRC code storage unit holds the CRC code received from the CRC code generation unit, and transmits the CRC code of the previous packet to the CRC code addition unit. The CRC code adding unit adds the CRC code of the data to the designated position in the packet corresponding to the CRC code of the previous packet received from the CRC code storage unit, and transmits the packet.

  On the receiving side, the CRC error checking unit recognizes the CRC code addition position in the packet based on the CRC code of the previous packet given from the CRC code storage unit, and performs error detection. The CRC code storage unit holds the received packet or the CRC code received from the CRC code position search unit, and transmits the CRC code of the previous packet to the CRC error check unit. When the CRC determination result given by the CRC error checking unit is NG, the CRC code position search unit searches the CRC code addition position of the packet, and the NG factor is “CRC erroneous determination of the previous packet” or “ It is determined which is “CRC error”.

  As a result, it is possible to detect a CRC misjudgment when an error occurs in both the data and the CRC code on the transmission line, and the result of division by the generator polynomial on the receiving side is zero. Hereinafter, the packet A, the packet B, and the packet C are specifically described as being transmitted and received in this order.

  For the transmission packet B, the position where the CRC code is added in the transmission packet B is designated by the CRC code of the immediately preceding transmission packet A. For this transmission packet B, an error occurs in the transmission data in the middle of communication, and an error also occurs in the CRC code. Further, these errors are not detected by the CRC error check in the reception packet B, and the CRC is erroneously determined. Suppose that

  In the subsequent transmission packet C, the CRC code of the transmission packet C is added to the designated position in the transmission packet C designated by the CRC code of the transmission packet B. On the other hand, in the reception packet C, it is interpreted that the CRC code of the transmission packet C is added to the designated position in the reception packet C due to an incorrect CRC code in the reception packet B. This should occur because the transmission history and the reception history are separately managed on the transmission side and the reception side. Since the reception side performs a CRC error check using a misinterpreted CRC code, a CRC error is naturally detected.

  However, if the received packet C is a packet correctly received from the transmission packet C, the CRC code of the transmission packet C should be added to the original correct position. Therefore, the reception side sequentially tries CRC error check using data at a plurality of predetermined positions in the packet as CRC codes. As a result, if there is a case where no CRC error is detected, it is assumed that the CRC error check result in the received packet B is a CRC error determination. However, the case where there is a packet loss in the received packet B is excluded.

  Note that if the CRC error of the received packet C is not resolved even after trying the CRC error check sequentially as described above, the CRC error of the received packet C is set.

  According to the present invention, in transmission data error detection using a CRC code, the transmission side determines the CRC addition position of the next packet according to the CRC code value of the previous packet, and the reception side determines the previous packet's CRC code. By performing the CRC error detection process by recognizing the CRC code addition position according to the CRC code value, an error occurs in both the data and the CRC code on the transmission line, and the division result in the generator polynomial on the receiving side is There is an effect that CRC misjudgment when the remainder becomes 0 can be detected.

[Description of configuration]
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of a CRC error determination detection apparatus according to an embodiment of the present invention. In FIG. 1, the transmission side includes a CRC code generation unit 11, a CRC code storage unit 12, and a CRC code addition unit 13. The receiving side includes a CRC error checking unit 14, a CRC code storage unit 15, and a CRC code position search unit 16.

  The CRC code generator 11 on the transmission side divides the transmission data by a predetermined generator polynomial and generates a remainder (CRC code). The CRC code storage unit 12 holds a predetermined part of the CRC code received from the CRC code generation unit 11, for example, the lower 3 bits, and transmits the CRC code of the previous packet to the CRC code addition unit 13. The CRC code adding unit 13 adds the CRC code of the transmission data to the designated position in the packet corresponding to the CRC code of the previous packet received from the CRC code storage unit 12, and transmits the packet.

  The CRC code storage unit 15 on the receiving side holds the received packet or the CRC code received from the CRC code position search unit 16 and transmits the CRC code of the previous packet to the CRC error check unit 14. The CRC error checking unit 14 recognizes the CRC code addition position in the packet from the CRC code of the previous packet given from the CRC code storage unit 15, and packet data if the CRC code is the original position, for example, the lower 3 bits Sort at the end of. Then, division is performed using the same generator polynomial as that on the transmission side. If there is no remainder, it is determined that the data is correct, and if there is a remainder, it is determined that there is a data transmission error.

  When the CRC determination result given by the CRC error checking unit 14 is NG, the CRC code position search unit 16 searches for the CRC code addition position of the packet, and the NG factor is “CRC erroneous determination of the previous packet” or “ It is determined whether the packet is a CRC error. The search for the CRC code addition position is realized by sequentially shifting the CRC code addition position and performing CRC error detection processing. The CRC error detection process is left to the CRC error checker 14.

  FIG. 2 is a packet configuration diagram showing a CRC code addition position of a CRC error determination detection system according to an embodiment of the present invention. In FIG. 2, a indicates the value of the lower n bits of the CRC code. In this example, n = 3 bits, and a takes a value from 0 to 7. b indicates the CRC code addition position determined based on a. In this example, b takes a value from 0 to 7.

  First, it is assumed that the CRC code (a = 3) in the packet # 1 is added at the position of b = 0. In this case, for the packet # 2 to be transmitted next, since the value a of the lower 3 bits of the CRC code of the previous packet (packet # 1) is 3, the CRC code (a = 7) of the packet # 2 is set to b. = 3 is added to the position. Similarly, in the packets # 3 and # 4, the CRC code of the packet is added to the position of b corresponding to the value a of the CRC lower 3 bits of the previous packet.

  Note that n is a parameter that can be arbitrarily set in the apparatus system if the transmission side and the reception side have the same value. The larger n is, the higher the CRC misjudgment detection accuracy is. However, it is a parameter that should be determined in consideration of the packet length range (particularly the minimum value) in the apparatus system and the allowable delay time required for error detection. Further, b is an arbitrary parameter that should be determined in advance between the transmission side and the reception side in the apparatus system. In FIG. 2 of this example, the end of the packet is set to b = 0 to 7. However, as long as it is within the packet, other than the end may be acceptable or distributed. However, since the division by the generator polynomial is generally performed sequentially from the first bit of the packet, the CRC code addition position is more collectively arranged at the end of the packet as shown in FIG. Search time is short.

[Description of operation]
Next, the operation of the present embodiment shown in FIGS. 1 and 2 will be described with reference to the flowcharts of FIGS. FIG. 3 shows a flowchart on the transmission side, and FIG. 4 shows a flowchart on the reception side.

  In the transmission side flowchart of FIG. 3, the CRC code generation unit 11 on the transmission side first determines the presence or absence of transmission data (step S1 in FIG. 3). When there is no transmission data, the current state is maintained, and when there is transmission data, the transmission data is divided by a predetermined generator polynomial to generate a remainder (CRC code) (step S2). The generated CRC code is output to the CRC code adding unit 13 and a predetermined part (hereinafter, described as lower 3 bits) is stored in the CRC code storage unit 12 (step S2).

  Next, the CRC code adding unit 13 determines the presence / absence of a packet transmission history (step S3). If there is no packet transmission history, for example, immediately after the apparatus is started up, the lower 3 bit value a of the CRC code of the previous packet is not set. For confirmation, a = 0 is set (step S4), and a CRC code is added to the position of b = 0 of the packet as in packet # 1 in FIG. 2 (step S6).

  If there is a packet transmission history, the lower 3 bit value of the CRC code of the previous packet is substituted for a (step S5). The CRC code of the previous packet is read from the CRC code storage unit 12. Referring to packet # 2 in FIG. 2, since the lower 3 bit value a of the CRC code of the previous packet (packet # 1) is 3, the data of packet # 2 is located at the position of b = 3 of packet # 2. The CRC code is added (step S6). Thereafter, in packet transmission, the CRC code addition position is determined according to the CRC code lower 3 bit value a of the previous packet. The packet with the CRC code added is transmitted toward the receiving side (step S7).

  On the other hand, in the receiving side flowchart of FIG. 4, the CRC error checking unit 14 on the receiving side first determines the presence or absence of a received packet (step T1 in FIG. 4). If there is no received packet, the current state is maintained, and if there is a received packet, the CRC error checking unit 14 determines whether there is a packet reception history (step T2).

  If there is no packet reception history, such as immediately after device startup, the lower 3 bit value a of the CRC code of the previous packet is unconfirmed, so a = 0 is set (step T3), and packet # 1 in FIG. Then, it is recognized that the CRC code of the packet is added at the position of b = 0, and the CRC code is moved to the tail and the CRC error detection process is performed (step T4).

  If there is a packet reception history, the CRC code of the previous packet is read from the CRC code storage unit 15 and its lower 3 bit value a is applied. Referring to packet # 2 in FIG. 2, since the lower 3 bit value a of the CRC code of the previous packet (packet # 1) is 3, the CRC code of packet # 2 is added at the position of b = 3. CRC error detection processing is performed (step T4). As a result of the CRC error detection process, when the CRC determination is OK (step T5), the value of the lower 3 bits of the CRC code of the packet is set to a (step T6), and the process returns to the packet reception determination sequence.

  On the other hand, when the CRC judgment is NG, the CRC code position search unit 16 searches for the position where the CRC code of the packet # 2 is added at b = 0 to 7 (step T7). The search is executed by sequentially reading a from each of b = 0 to 7 and performing CRC determination. As a result of the search, if the CRC judgment is OK (step T8), the value of the lower 3 bits of the CRC code of the packet is set at the position b (step T9), and the process returns to the packet reception judgment sequence. The presence / absence of packet loss in the previous packet is determined (step T10).

  The packet loss detecting means here does not depend on the present invention, and is performed, for example, by checking the continuity of numbers sequentially assigned to consecutive packets, such as the fragment offset of the IP header. Assume that loss ALM is issued (step T11). As a result of the packet loss determination of the previous packet, when there is no packet loss and there is no CRC error of the previous packet (step T12), it is determined that there was a CRC erroneous determination in the previous packet, and the previous packet CRC erroneous determination ALM is issued (step T13). If there is a CRC error in the previous packet (step T12), no ALM is issued (step T14).

  If the CRC determination is NG after the CRC code position search (step T7) (step T8), a = 0 is set (step T15), the process returns to the packet reception determination sequence, and the packet CRC error is detected. Is issued (step T16).

  Next, the operation of the present embodiment described above will be described in more detail with reference to the time charts of FIG. 5, FIG. 6, FIG. 7, and FIG. FIG. 5 is a time chart on the transmission side, FIG. 6 is a time chart on the reception side (when OK), FIG. 7 is a time chart on the reception side (when CRC misjudgment is detected), and FIG. Indicates packet loss).

  The operation when the transmission data is four data from # 1 to # 4 will be described with reference to the transmission side time chart of FIG. Data # 1 indicates head data when there is no packet transmission history, such as immediately after the apparatus is started up.

  First, the transmission data # 1 is divided by a predetermined generator polynomial to generate a CRC code (a = 3). When the generated CRC code (a = 3) is added to the data # 1, the lower 3 bit value a of the CRC code of the previous packet is referred to. However, since there is no transmission history at this time, the initial value 0 is applied, and the CRC code a = 3 is added to the position where the CRC code addition position b = 0. Thus, a signal obtained by adding the CRC code a = 3 to the position of b = 0 in the transmission data # 1 is transmitted as the transmission packet # 1.

  Transmission data # 2 is also divided by a predetermined generator polynomial to generate CRC code a = 7. When the generated CRC code a = 7 is added to the data # 2, the CRC code lower 3 bit value a = 3 of the previous packet packet # 1 is referred to, and the CRC code a = 7 is set at the CRC code addition position b = 3. Is added. Thus, a signal obtained by adding the CRC code a = 7 to the position of b = 3 in the transmission data # 2 is transmitted as the transmission packet # 2.

  Similarly, the generated CRC code a = 2 is added to the position of b = 7 for the transmission data # 3, the generated CRC code a = 5 is added to the position of b = 2 for the transmission data # 4, and the packet Send.

  Next, referring to the reception side time chart of FIG. 6 (during OK), the operation when the received packets are 4 packets from # 1 to # 4 and the CRC judgment is all OK will be described. Received packet # 1 indicates the first packet when there is no packet reception history, such as immediately after the apparatus is started up.

  First, when performing CRC error detection of the received packet # 1, the CRC code lower 3 bit value a of the previous packet is referred to in order to know the position of the CRC code. However, since there is no reception history at this time, the initial value 0 is applied, and it is recognized that the CRC code a = 3 is added to the CRC code addition position b = 0. Then, the CRC code a = 3 at the position of b = 0 is moved to the end of the data, and division is performed with a predetermined generator polynomial from the beginning of the data. If there is no remainder of the division result, the data is correct and there is a remainder. If there is a data transmission error, it is determined.

  When the CRC error detection is performed also for the received packet # 2, the CRC code lower 3 bit value a = 3 of the previous packet is referred to know the position of the CRC code, and the CRC code a is set at the CRC code addition position b = 3. = 7 is recognized. Then, the CRC code a = 7 at the position of b = 3 is moved to the end of the data, and division is performed with a predetermined generator polynomial from the beginning of the data. If there is no remainder of the division result, the data is correct and there is a remainder. If there is a data transmission error, it is determined.

  Similarly, it is recognized that the CRC code a = 2 is added to the position of b = 7 for the received packet # 3, and error detection is performed. For the received packet # 4, the CRC code a is set to the position of b = 2. = 5 is recognized and error detection is performed.

  Next, the operation when a CRC erroneous determination occurs in the # 2 packet among the four received packets from # 1 to # 4 will be described with reference to the reception side time chart of FIG. Received packet # 1 indicates the first packet when there is no packet reception history, such as immediately after the apparatus is started up, and the operation of the reception process is as described with reference to FIG.

  In received packet # 2, an error occurs in both data and CRC on the transmission path, and the correct CRC code a = 7 added to the position of b = 3 on the transmission side becomes the incorrect CRC code a = 4. It is assumed that the result of division by a predetermined generator polynomial is not so much even though it has been.

  For the received packet # 2, when performing CRC error detection, the CRC code lower 3 bit value a = 3 is referred to know the CRC code position, and the CRC code is added to the CRC code addition position b = 3. It is recognized that is added. Here, although the lower 3 bit value of the original correct CRC code is a = 7, it is erroneously recognized as a = 4 due to a transmission path error.

  Then, the erroneous CRC code a = 4) at the position of b = 3 is moved to the end of the data, and division is performed with a predetermined generator polynomial from the top of the data. Normally, the remainder of the division result occurs and the CRC judgment is NG. However, if an error is made such that the result of the accidental division is zero on the transmission line, error detection cannot be performed and the CRC judgment is OK. If it exists, it will be misjudged.

  At this time, the process proceeds to the received packet # 3 with erroneous determination. When performing CRC error detection for received packet # 3, the CRC code lower 3 bit value a = 4 is referred to know the position of the CRC code, and the CRC code is added at the position of b = 4 Recognize. Here, although the original correct CRC code addition position is b = 7, since the CRC code of the previous packet is incorrect, the data at the position of b = 4 is erroneously recognized as the CRC code.

  Then, the data at the position of b = 4 is moved to the end of the data, and division is performed from the top of the data by a predetermined generator polynomial. As a result, as a matter of course, the remainder is not 0, and the CRC judgment is NG. Therefore, the sequence moves to a CRC code position search sequence, assuming that any of b = 0 to 7 of packet # 3 is a CRC code, and moves each to the end of the data and divides by a predetermined generator polynomial. Search for the position of the CRC code.

  As a result, the data obtained by dividing the data at the position of b = 7 to which the CRC code is added on the transmission side is assumed to be a CRC code, and the remainder is 0, and it is found that b = 7 is the correct CRC code addition position. Furthermore, if there is no packet loss of the previous packet, it can be determined that the CRC determination of the previous packet was an erroneous determination. In this way, even when a CRC misjudgment occurs in the previous packet, it can be detected that a CRC misjudgment has occurred in the next packet.

  In the CRC code position search, it has been found that the lower 3 bit value of the correct CRC code is 2, so a = 2 is held as the lower 3 bit value of the CRC code of the previous packet. By doing so, it is possible to recognize that the received packet # 4 is correctly added with the CRC code a = 5 at the position of b = 2 and perform error detection processing.

  Next, with reference to the reception side time chart of FIG. 8 (during packet loss), the operation when a packet loss occurs in the # 2 packet among the four packets # 1 to # 4 will be described. . Received packet # 1 indicates the first packet when there is no packet reception history, such as immediately after the apparatus is started up, and the operation of the reception process is as described with reference to FIG. Since the received packet # 2 has lost a packet on the transmission path, the receiving side receives the packet # 3 after the packet # 1.

  When detecting CRC error of received packet # 3, the CRC code lower 3 bit value a = 3 is referred to know the position of the CRC code, and the CRC code is added at the position of b = 3 Recognize. Here, although the original correct CRC code addition position is b = 7, since packet # 2 has been lost, the value a of the lower 3 bits of the CRC code of the previous packet is not correctly updated, and the value a of packet # 1 = 3, the data at the position of b = 3 is erroneously recognized as a CRC code.

  Then, the data at the position of b = 3 is moved to the tail of the data, and division is performed with a predetermined generator polynomial from the top of the data. As a result, as a matter of course, the remainder is not 0, and the CRC judgment is NG. Therefore, the sequence moves to a CRC code position search sequence, assuming that any of b = 0 to 7 of packet # 3 is a CRC code, and moves each to the end of the data and divides by a predetermined generator polynomial. Search for the position of the CRC code.

  As a result, the data obtained by dividing the data at the position of b = 7 to which the CRC code is added on the transmission side is assumed to be a CRC code, and the remainder is 0, and it is found that b = 7 is the correct CRC code addition position. Here, if the loss of the previous packet is found, the packet loss ALM of the previous packet is issued, and it is not a CRC misjudgment. Here, the packet loss detecting means is not limited to the present invention, but is performed by checking the continuity of numbers sequentially allocated to consecutive packets, such as the fragment offset of the IP header.

  In the CRC code position search, it has been found that the lower 3 bit value of the correct CRC code is 2, so a = 2 is held as the lower 3 bit value of the CRC code of the previous packet. By doing so, it is possible to recognize that the received packet # 4 is correctly added with the CRC code a = 5 at the position of b = 2 and perform error detection processing.

The block diagram which shows the structure of the principal part of the CRC misjudgment detection apparatus by one Example of this invention. Packet configuration diagram showing CRC code addition position in one embodiment of the present invention The flowchart which shows operation | movement of the transmission side by one Example of this invention. The flowchart which shows operation | movement of the receiving side by one Example of this invention. The time chart which shows the operation | movement of the transmission side by one Example of this invention The time chart which shows the operation | movement (at the time of OK) of the receiving side by one Example of this invention FIG. 4 is a time chart showing the operation on the receiving side (when a CRC error determination is detected) according to an embodiment of the present invention; 4 is a time chart showing the operation (at the time of packet loss) on the receiving side according to an embodiment of the present invention. Block diagram showing the configuration of an error detection method using a conventional CRC code Packet configuration diagram showing conventional CRC code addition position

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 CRC code production | generation part 12 CRC code memory | storage part 13 CRC code addition part 14 CRC error inspection part 15 CRC code memory | storage part 16 CRC code position search part 91 CRC code generation part 92 CRC code addition part 93 CRC error inspection part

Claims (5)

On the transmission side, a transmission packet in which the CRC code of the transmission data is added to the position in the packet determined by the CRC code value of the previous transmission data is transmitted,
On the receiving side, the data at the position in the packet determined by the CRC code value of the immediately preceding received packet is moved to the original CRC position to perform a CRC error check, and when a CRC error is detected, The CRC error check is performed sequentially using the data at the position in the packet as a CRC code. If no CRC error is detected, the previous received packet is not lost and there is no CRC error. A CRC misjudgment detection method, wherein a CRC error is detected for the received packet when a CRC error is detected even if CRC error checking is performed sequentially. The sender is
A procedure for generating a CRC code for transmission data;
A procedure for sequentially storing at least the CRC code generated for the immediately preceding transmission data;
A step of transmitting a transmission packet added to a position in a packet determined by a CRC code value generated for the immediately preceding stored transmission data, the CRC code of the transmission data;
The receiving side
A procedure for storing data at a position in a packet determined by at least the CRC code value of the immediately preceding received packet;
Moving the stored data to the original CRC position and performing a CRC error check on the received packet;
When a CRC error is detected as a result of the CRC error check, a procedure of sequentially repeating the CRC error check with data at a plurality of predetermined positions in the received packet as CRC codes;
If no CRC error is detected while repeating the CRC error check, the CRC error check is erroneously determined if there is no loss and no CRC error for the immediately preceding received packet;
A CRC misjudgment detection method comprising a step of setting a CRC error for the received packet when a CRC error is detected even after repeating the CRC error check.   3. The CRC misjudgment detection method according to claim 1, wherein the in-packet position is determined by lower n bits of a CRC code.   4. The CRC misjudgment detection method according to claim 1, wherein the original CRC position is the end of the packet. The sender is
A CRC code generator for generating a CRC code for transmission data;
A CRC code storage unit for sequentially storing CRC codes generated for at least the immediately preceding transmission data;
A CRC code adding unit for transmitting a transmission packet added to a position in the packet determined by the value of the CRC code generated for the transmission data immediately before the CRC code of the transmission data;
The receiving side
A CRC code storage unit for storing data at a position in the packet determined by at least the CRC code value of the immediately preceding received packet;
A CRC code error checking unit that moves the stored data to an original CRC position and performs a CRC error check on the received packet;
When a CRC error is detected as a result of the CRC error check, the CRC error check is sequentially repeated with data at a plurality of predetermined positions in the received packet as CRC codes, and no CRC error is detected in the meantime. If there is no packet loss and no CRC error with respect to the immediately preceding received packet, the CRC error check is determined to be erroneous, and when a CRC error is detected, a CRC code position search unit is provided that sets the CRC error for the received packet. A CRC misjudgment detection device as a feature.

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