Splitting and reassembling method for improving transmission efficiency and reliability of security protocol data unit

Abstract

The present invention relates to the field of communication technology, and specifically to a splitting and reorganizing method for improving the transmission efficiency and reliability of a security protocol data unit. The present invention is based on the framework of the IEC61784-3 standard, and inserts a module using a random additive noise decoding algorithm between a security communication layer and a black channel, which is used for error correction processing of a CRC-encoded SPDU, and can seamlessly connect to the standard black channel security communication protocol architecture, facilitate performance expansion and promotion in industrial scenarios, and propose a splitting / reorganizing mechanism for a long SPDU: split the long SPDU from the security communication layer to form multiple short packet SPDUs, which is convenient for guessing and decoding at the receiving end, improving the transmission reliability of the SPDU, and reducing the probability of retransmission. Parallel guessing and decoding are performed on the short packet SPDU from the black channel, and the decoding complexity is significantly reduced, and the performance is significantly improved compared with the traditional CRC error detection mechanism, thereby solving the problem of poor transmission reliability of the existing security protocol data unit.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a splitting and reassembling method for improving the transmission efficiency and reliability of a safety protocol data unit. Background Art

[0002] With the rapid development of information communication, computer networks, big data, robots and artificial intelligence, manufacturing plants are rapidly moving towards automation, digitization and intelligence. Tens of thousands of sensors, actuators and smart devices are distributed in various links of the production line, and data is transmitted and controlled through the IIoT network system. For critical control commands such as emergency interruption and fire alarm, high data security needs to be guaranteed.

[0003] The receiving end first performs CRC error detection. If it passes, the SPDU is considered correct. If it fails, it is discarded and retransmission is requested. When the channel noise is a legal CRC codeword, the sum of the SPDU and the noise is still a legal CRC codeword, resulting in residual errors in the SPDU at the receiving end. In the worst industrial application scenarios, the SPDU has a large frame error rate (PER), resulting in frequent SPDU retransmissions, which seriously affects the data transmission performance of the IIoT system. Summary of the invention

[0004] The purpose of the present invention is to provide a splitting and reassembling method for improving the transmission efficiency and reliability of a safety protocol data unit, aiming to solve the problem of poor transmission reliability of existing safety protocol data units.

[0005] To achieve the above object, the present invention provides a splitting and reassembling method for improving the transmission efficiency and reliability of a security protocol data unit, comprising the following steps:

[0006] The SPDU processing unit splits the long SPDU from the security communication layer to obtain multiple short packet SPDUs;

[0007] The short packet SPDU after splitting and CRC encoding is transmitted to the SPDU processing unit through the black channel;

[0008] The SPDU processing unit inputs the received short packet SPDU in parallel into the decoder for guessing decoding;

[0009] After all the short SPDUs are processed by the decoder, the SPDU processing unit reassembles them in sequence to form a long SPDU;

[0010] Evaluate and optimize the performance of the split / recombination mechanism.

[0011] The black channel includes an application layer, a data link layer and a physical layer.

[0012] The decoder is a GRAND decoder, which uses a GRAND algorithm to correct errors in the SPDU.

[0013] The evaluation and optimization of the performance of the splitting / recombining mechanism includes:

[0014] Evaluate the performance of the splitting / recombination mechanism and obtain evaluation results;

[0015] The splitting / recombination mechanism is optimized based on the evaluation results.

[0016] The evaluation results include bit error rate, packet frame error rate, decoding complexity and residual error probability.

[0017] The decoding complexity is the average value of the sum of decoding complexities of all short packets SPDU.

[0018] The residual error probability is the probability distribution of error bits in the reorganized SPDU after guessing decoding, which is used to calculate the residual error probability R CRC (P e ).

[0019] The splitting and reassembling method for improving the transmission efficiency and reliability of a security protocol data unit of the present invention comprises the following steps: a SPDU processing unit splits and processes a long SPDU from a security communication layer to obtain a plurality of short packet SPDUs; the short packet SPDUs after splitting and CRC encoding are transmitted to the SPDU processing unit through a black channel; the SPDU processing unit inputs the received short packet SPDUs in parallel into a decoder for guess decoding; after all the short packet SPDUs have been processed by the decoder, the SPDU processing unit reassembles them in sequence to form a long SPDU; and the performance of the splitting / reassembling mechanism is evaluated and optimized. The present invention is based on the framework of the IEC61784-3 standard. A module using a random additive noise decoding algorithm is inserted between the security communication layer and the black channel for error correction processing of CRC-encoded SPDUs. It can seamlessly connect to the black channel security communication protocol architecture of the IEC61784-3 standard, which is very convenient for performance expansion and promotion in industrial scenarios. A split / reorganization mechanism for long SPDUs is proposed: the long SPDU from the security communication layer is split to form multiple short packet SPDUs, which is convenient for guessing and decoding at the receiving end, improves the transmission reliability of SPDUs, and reduces the probability of retransmission. Parallel guessing and decoding are performed on the short packet SPDUs from the black channel, and the decoding complexity is significantly reduced, which is engineering feasible; the original long SPDU is reorganized and restored, and the BER, PER and REP performance of the SPDU are significantly improved compared with the traditional CRC error detection mechanism, thereby solving the problem of poor transmission reliability of the existing security protocol data unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is the basic schematic diagram of the "black channel" of the IEC61784-3 standard.

[0022] Figure 2 is a schematic diagram of the SPDU processing unit.

[0023] Figure 3 It is a schematic diagram of splitting a long SPDU and performing CRC encoding to form multiple short packet SPDUs.

[0024] Figure 4 It is a schematic diagram of a short SPDU being reassembled into a long SPDU after GRAND error correction.

[0025] Figure 5 It is a comparison of BER performance under different maximum error correction capabilities M.

[0026] Figure 6 and Figure 7 It is a comparison of PER performance under different SPDU lengths n and maximum error correction capabilities M.

[0027] Figure 8 and Fig. 9 This is the comparison of the corresponding decoding complexity under the condition that the reassembled SPDU length is 1024 bits.

[0028] Fig.10 The present invention provides a flow chart of a splitting and reassembling method for improving the transmission efficiency and reliability of a security protocol data unit.

[0029] Fig.11 It is a flow chart for evaluating and optimizing the performance of the splitting / recombination mechanism. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] See also Figures 1 to 11 The present invention provides a splitting and reassembling method for improving the transmission efficiency and reliability of a security protocol data unit, comprising the following steps:

[0032] S1: The SPDU processing unit splits the long SPDU from the security communication layer to obtain multiple short packet SPDUs;

[0033] Specifically, let the length of the short packet SPDU payload be n s In the SPDU processing unit, the SPDU with a length of n bits from the security communication layer is split and processed to obtain Short SPDU. In general, n is not n s Therefore, it is necessary to add Each short packet SPDU is CRC-encoded, which is equivalent to adding r at the end of the short packet SPDU. s The CRC signature of the short packet SPDU is .

[0034] S2: The short packet SPDU after splitting and CRC encoding is transmitted to the SPDU processing unit through the black channel; the black channel includes the application layer, the data link layer and the physical layer.

[0035] Specifically, all short packets SPDU are transmitted to the SPDU processing unit through the black channel respectively.

[0036] S3: The SPDU processing unit inputs the received short packet SPDU in parallel into the decoder for guess decoding;

[0037] The decoder is a GRAND decoder, which uses the GRAND algorithm to correct errors in the SPDU.

[0038] Specifically, after the SPDU processing unit receives the short packet SPDU from the black channel, each short packet SPDU is input into the GRAND decoder in parallel to correct possible errors.

[0039] S4: After all the short SPDUs are processed by the decoder, the SPDU processing unit reassembles them in sequence to form a long SPDU;

[0040] Specifically, after all the short SPDUs have been processed, they are reassembled in order to form a long SPDU. s =64 bits, and the length of 8 short SPDUs is 512 bits. If there are l=5 error bits in a short SPDU and other short SPDUs are error-free, the maximum decoding complexity is 7.624510, which is more than 40,000 times lower than the decoding complexity of the long SPDU when it is not split.

[0041] S5: Evaluate and optimize the performance of the split / recombination mechanism.

[0042] S51: Evaluate the performance of the splitting / recombination mechanism and obtain an evaluation result;

[0043] The evaluation results include bit error rate, packet frame error rate, decoding complexity and residual error probability.

[0044] Specifically, since each short packet SPDU has been error-corrected, the BER of the reassembled long SPDU will be significantly lower than that of the unsplit / reassembled SPDU. CRC (P e ) will also be significantly reduced. BER performance. Considering the length of the short packet SPDU g s = 64 bits, and the reassembled long SPDU has an integer number of short SPDUs. Therefore, the BER performance of SPDUs of different lengths is the same and is related to the maximum error correction capability M of the GRAND decoder. Figure 5 As shown, M=0 represents the BER performance of the traditional CRC error detection mechanism. Figure 5 It shows that CRC8 and CRC16 have the best BER performance when M=1 and M=2 respectively. When the M value increases, the BER performance not only does not improve, but deteriorates. The reason is that the error detection capabilities of CRC8 and CRC16 are relatively weak. When the guessed random additive noise decoding algorithm is used, the modulo-two addition of the channel noise and the noise error pattern generated by the GRAND decoder has a high probability of being a legal CRC codeword, which can pass the traditional CRC error detection, but it is a missed detection. When CRC24 and CRC32 are used, because the signature length of these two CRC codes is large and has strong error detection capabilities, the probability of missed detection when the GRAND decoding algorithm is used is extremely small, so it has excellent error correction capabilities. Furthermore, P e The smaller the value, the smaller the probability of erroneous bits in the SPDU. Under the same error correction capability, the longer the CRC code signature length, the stronger the error detection capability and the better the BER performance. Figure 5 It shows that the BER performance is significantly improved by using the GRAND decoding algorithm.

[0045] PER performance. Set the length of the short packet SPDU g s = 64 bits, under different SPDU lengths and maximum error correction capability M, P e =10 -2 and P e =10 -3 The corresponding PER performance comparison is as follows Figure 6As shown in the figure, M=0 represents the PER performance corresponding to the traditional CRC error detection mechanism. When a long SPDU is split into multiple short SPDUs for transmission, the reassembled SPDU is considered correct only when these received short SPDUs are decoded through guesswork and all pass CRC error detection.

[0046] Therefore, under the same Pe condition, the more short SPDUs are split, the worse the PER performance will be. For CRC8 and CRC16, the PER performance is best when M=1 and M=2 respectively. When the reassembled SPDU length n and the maximum error correction capability M are the same, the CRC signature length r s The larger the value, the stronger the error correction and detection capabilities. Compared with the traditional CRC error detection mechanism (M=0), the PER performance improvement is also more significant.

[0047] Guess decoding complexity. According to the GRAND algorithm, the GRAND decoder generates a noise error pattern each time, and performs a guess decoding operation and queries whether the decoding is successful, until the guessed decoding is correct or the maximum decoding complexity is reached. The decoding complexity is the average of the sum of the decoding complexities of all short packets SPDU. When the reassembled SPDU length n=1024 bits, the decoding complexity corresponding to different CRC code types and maximum error correction capability M is compared as follows Figure 7 As shown in the figure, at the expense of better BER, PER and REP performance. Figure 7 It shows that under the same CRC code type, the larger the maximum error correction capability M, the greater the decoding complexity. When the M value is the same, the larger the CRC signature length M, the stronger the error correction and detection capability, and the greater the decoding complexity; REP performance comparison. After guessing and decoding, the probability distribution of the error bits in the reorganized SPDU is statistically analyzed to calculate the residual error probability R CRC (P e ). Since CRC8 has a relatively general effect on improving BER and PER performance, the REP performance of (CRC16, M=2), (CRC24, M=4) and (CRC32, M=4) is examined. e =10 -2 and P e =10 -3 Under the condition of Figure 8 As shown in Figure 2, it can be seen that under different reassembled SPDU length conditions, the REP performance has been significantly improved, and the CRC signature length r s The larger it is, the smaller the REP is, which means the residual error probability is smaller and the transmitted SPDU is more secure and reliable.

[0048] S52: Optimizing the splitting / recombination mechanism based on the evaluation result.

[0049] Specifically, BER performance: Figure 5 As shown in Figure 1, the GRAND decoding algorithm is used to significantly improve the BER performance. Figure 6 As shown in Figure 2, for CRC8 and CRC16, PER performance is best when M=1 and M=2, respectively. Figure 7 As shown in the figure, under the same CRC code type, the larger the maximum error correction capability M value, the greater the decoding complexity. Figure 8 As shown in the figure, under different reassembled SPDU length conditions, the REP performance is significantly improved.

[0050] Beneficial effects:

[0051] 1. The splitting and reassembly method for improving the transmission efficiency and reliability of the security protocol data unit provided by the present invention is based on the framework of the IEC61784-3 standard. An SPDU processing module is inserted between the security communication layer and the black channel for error correction processing of the CRC-encoded SPDU. It can seamlessly connect to the black channel security communication protocol architecture of the IEC61784-3 standard, which is very convenient for performance expansion and promotion in industrial scenarios.

[0052] 2. The splitting and reassembling method for improving the transmission efficiency and reliability of the security protocol data unit provided by the present invention has a splitting / reassembling mechanism for the long SPDU: a) splitting the long SPDU from the security communication layer to form multiple short packet SPDUs, which is convenient for guessing and decoding at the receiving end, improving the transmission reliability of the SPDU and reducing the probability of retransmission. b) parallel guessing and decoding are performed on the short packet SPDU from the black channel, and the decoding complexity is significantly reduced, which has engineering feasibility; reassembling and restoring the original long SPDU, and making the BER, PER and REP performance of the SPDU significantly improved compared with the traditional CRC error detection mechanism.

[0053] What is disclosed above is only a preferred embodiment of the splitting and reassembling method of the present invention for improving the transmission efficiency and reliability of security protocol data units. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A splitting and reassembling method for improving the transmission efficiency and reliability of a security protocol data unit, characterized in that: The following steps are involved: The SPDU processing unit splits the long SPDU from the security communication layer to obtain multiple short packet SPDUs; The short packet SPDU after splitting and CRC encoding is transmitted to the SPDU processing unit through the black channel; The SPDU processing unit inputs the received short packet SPDU in parallel into the decoder for guessing decoding; After all the short SPDUs are processed by the decoder, the SPDU processing unit reassembles them in sequence to form a long SPDU; Evaluate and optimize the performance of the split / recombination mechanism; The decoder is a GRAND decoder, which uses a GRAND algorithm to correct errors in the SPDU; The performance evaluation and optimization of the splitting / recombination mechanism includes: Evaluate the performance of the splitting / recombination mechanism and obtain evaluation results; Optimizing the splitting / recombination mechanism based on the evaluation results; The evaluation results include bit error rate, packet frame error rate, decoding complexity and residual error probability; The decoding complexity is the average value of the sum of decoding complexities of all short packets SPDU.

2. The method for splitting and reassembling a security protocol data unit to improve transmission efficiency and reliability as claimed in claim 1, characterized in that: The black channel includes an application layer, a data link layer and a physical layer.

3. The method for splitting and reassembling a security protocol data unit to improve transmission efficiency and reliability as claimed in claim 1, characterized in that: After guessing and decoding, the probability distribution of the error bits in the reassembled SPDU is statistically analyzed to calculate the residual error probability.

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