A method for implementing 1553B bus communication protocol through power lines

Abstract

The invention discloses a method for realizing a 1553B bus communication protocol through a power line, comprising the following steps: S1, grouping communication data to be transmitted according to the 1553B bus communication protocol and generating corresponding words, and assembling the words into a message and frame structure with more complex content with the words as basic units; then, taking the words as the minimum encoding objects, encoding the words word by word into a Manchester II type two-phase level code form; S2, sampling the Manchester II type two-phase level code at a 2-fold rate for each bit, and generating 2 data bits of corresponding level polarities according to the polarities of the levels of the first 1 / 2 bit and the last 1 / 2 bit; S3, realizing a power carrier communication physical layer with an orthogonal frequency division multiplexing technology, and transmitting the data bits on the power line by coupling with the power line.

Description

Technical Field

[0001] The present invention relates to the field of communication, and in particular to a communication method which comprehensively utilizes the advantages of a power line carrier communication physical layer and a 1553B bus protocol. Background Art

[0002] Power line carrier communication is a communication method that uses power lines as a channel medium to achieve data transmission. In the early days, power line carrier communication technology was mainly used in applications such as power grid monitoring and control, relay protection, and remote equipment control information transmission. As a transmission method that can use the configured power line network to transmit signals without laying additional communication lines, power line communication has obvious characteristics and has the advantages of wide coverage area. It has been more and more widely used in recent years.

[0003] The 1553B bus protocol is currently an internationally recognized data bus standard, widely used in aircraft integrated avionics systems, external storage management and integration systems, and gradually expanded to flight control systems, as well as ships, aerospace, industrial control and other fields. The transmission medium of the 1553B bus is generally a shielded twisted pair, coupled through a transformer, and can also be transmitted using coaxial cables, optical cables, etc. The main features of the 1553B bus protocol are distributed processing, centralized control and real-time response, with high real-time performance and high reliability.

[0004] Power carrier communication can make full use of the power line network that powers the equipment. Its biggest feature is that it does not need to re-build the traditional communication media such as coaxial cables, twisted pairs, and optical fibers required for the communication network. As long as there are wires, communication transmission can be carried out through the wires. In some occasions where it is not suitable to re-lay network cables / optical fibers, or the cost of re-laying traditional network cables is too high, or in some occasions where space / weight restrictions do not allow for additional communication cables, directly using power supply wires as communication media for communication becomes a feasible solution.

[0005] As a commonly used command / response communication protocol, the 1553B bus protocol has high real-time performance and reliability and has been widely used in many fields. Combining power carrier communication and the 1553B bus protocol and making full use of their respective characteristics and advantages will effectively solve application problems in some specific occasions. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a new method for achieving high real-time and high reliability network communication in the above-mentioned occasions where it is not suitable to re-lay network cables / optical fibers, or the cost of re-laying traditional network cables is too high, or there are space / weight limitations and no more communication cables can be added.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for implementing a 1553B bus communication protocol through a power line comprises the following steps: S1, grouping communication data to be transmitted according to the 1553B bus communication protocol and generating corresponding words, and assembling the words into a message and frame structure with more complex content with the words as basic units; then taking the words as the minimum encoding object, encoding word by word into the form of Manchester II type two-phase level code; S2, sampling the Manchester II type two-phase level code at a rate of 2 times, and generating 2 data bits of corresponding level polarity according to the polarity of the level of the first 1 / 2 bit time and the last 1 / 2 bit time; S3, realizing the physical layer of power carrier communication by orthogonal frequency division multiplexing technology, and transmitting the data bits on the power line by coupling with the power line.

[0009] Further, step S1 specifically includes: S11, grouping each 16 bits of data to be transmitted into a group as valid bits; S12, performing parity check on the 16 bits of data to generate 1 parity check bit;

[0010] S13, encode the 17-bit data generated by steps S11 and S12 by Manchester II type two-phase level code; S14, generate a corresponding type of synchronization header according to the specific attributes of the transmitted data, each synchronization header consists of two bits but occupies 3 bits of a specific shape of level code; S15, assemble the synchronization header, valid bit and parity check bit that have completed Manchester II type two-phase level code encoding into words, each word occupies a total of 20 bits; S16, repeat steps S11 to S15, assemble several words into messages with richer content expression, and further assemble several messages into frames.

[0011] Further, step S2 specifically includes: S21, taking a word as a basic unit, reading a Manchester II type biphase level code sequence of 20 bits; S22, taking 1 / 2 bit time as a sampling unit, resampling each Manchester biphase level code of each bit time into two independent levels connected in sequence, and converting the level polarity information into a corresponding data bit; S23, repeating steps S21 to S22, and continuously resampling and converting the Manchester II type biphase level code sequence to be transmitted.

[0012] Furthermore, the physical layer described in step S3 is responsible for OFDM modulating the data generated in step S2 in the transmitting direction and coupling the signal to the power line for transmission; in the receiving direction, the physical layer demodulates the signal received from the power line through OFDM, recovers the communication data and feeds it back to step S2.

[0013] Furthermore, the process of the physical layer transmitting end in step S3 is: A1, receiving the data bit sequence after resampling and conversion output from step S2; A2, FEC encoding and interleaving of data bits; A3, sending preamble; A4, inserting pilot; A5, IFFT operation; A6, inserting CP; A7, windowing and shaping filtering; A8, DAC conversion; A9, coupling the signal generated by DAC to the power line for transmission through the PLC analog front end; the process of the physical layer receiving end in step S3 is: B1, starting the PLC analog front end, collecting the signal on the power line and performing ADC conversion; B2, synchronous detection, and stripping CP; B3, FFT and channel estimation; B4, deinterleaving; B5, feeding back the deinterleaved data output to step S2.

[0014] The beneficial effect of the technical solution of the present invention is that the method of implementing the 1553B bus communication protocol through power lines of the present invention comprehensively utilizes the respective characteristics and advantages of the power carrier communication physical layer and the 1553B bus communication protocol layer, and can directly use the power supply cable for data transmission without additional wiring, while having the advantages of good real-time performance, high efficiency and high reliability of the 1553B bus. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The overall flow diagram of the embodiment of the present invention is that the communication data is assembled into words, messages and frames according to the 1553B bus protocol, and then a data bit sequence of Manchester II type biphase level code re-sampled is generated, and communication transmission is performed through the power carrier communication physical layer;

[0016] Figure 2 The present invention is a schematic diagram of a process of converting communication data bits into a Manchester II type bi-phase level code format used in a 1553B protocol, and then resampling the Manchester bi-phase level code format at a rate of 2 times to generate corresponding data bits;

[0017] Figure 3 The present invention provides a processing flow of an OFDM-based power line carrier communication transmitter and receiver. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0019] The embodiment of the present invention proposes a method for implementing a 1553B bus communication protocol through a power line, and the method can be decomposed into two parts: transmission and reception.

[0020] refer to Figure 1The transmission process generally includes steps S1 to S3: S1, grouping the communication data to be transmitted according to the 1553B bus protocol and generating corresponding words, and assembling them into structures such as messages and frames with more complex contents with words as the basic unit; then, taking words as the minimum encoding object, encoding them word by word into the form of Manchester II type biphase level code, and outputting them to step S2; S2, re-sampling the Manchester II type biphase level code sequence at a 2x rate, generating a data bit sequence of corresponding polarity, and outputting them to step S3; S3, realizing the modulation function based on OFDM, coupling the generated analog signal to the power line for transmission.

[0021] Continue to refer Figure 1 The receiving process is as follows: receiving the signal on the power line by coupling, completing OFDM demodulation, and outputting demodulated data; then converting the demodulated data into Manchester II type biphase level code, and finally extracting the specific information of the frame, message, and word according to the 1553B bus protocol.

[0022] Specifically, step S1 includes S11 to S17:

[0023] S11, grouping each 16 bits of data to be transmitted into a group as valid bits;

[0024] S12, performing parity check on the 16-bit data to generate 1 parity check bit;

[0025] S13, performing Manchester II type biphase level code conversion on the 17-bit data generated in the above steps S11 and S12;

[0026] S14, according to the type of transmitted data, generating a synchronization header of a corresponding instruction word, status word or data word, no matter what kind of synchronization header, it is a specific code pattern different from the normal Manchester II type biphase level code, and is composed of a level code of a specific shape when occupying 3 bits in total;

[0027] S15, assembling the synchronization header, valid information and check bit that have completed Manchester code conversion into words, each word occupies 20 bits in total;

[0028] S16, repeating steps S11 to S15, assembling a plurality of words into a message, and then assembling a plurality of messages into a frame;

[0029] S17, taking the word as the smallest encoding object, encoding each word into the Manchester II type bi-phase level code form, and outputting to step S2.

[0030] The main function of step S2 is to realize the conversion from Manchester II type biphase level code to re-sampling at 2 times the rate to generate data. The specific steps are as follows S21~S24. If the data is generated from 2 times the rate sampling to Manchester II type biphase level code, the reverse operation is performed.

[0031] S21, receiving the Manchester II type biphase level code from step S1, taking word as basic unit, reading the Manchester II type biphase level code when 20 bits;

[0032] S22. Take 1 / 2 of the Manchester bi-phase level code duration as the sampling unit, and resample each bit of the Manchester bi-phase level code into independent two-bit data bit levels. For example, the characteristics of the Manchester bi-phase level code representing the data bit "1" are: the level of the first 1 / 2 bit is high, and the level of the second 1 / 2 bit is low. After resampling, the level of the first 1 / 2 bit is quantized to 1, and the level of the second 1 / 2 bit is quantized to 0. That is, the original 1-bit data "1" to be transmitted is represented by 2 bits of "10" after resampling and quantization; and the original data "0" to be transmitted is represented by 2 bits of "01" after resampling and quantization. The specific conversion diagram of the level code can be seen. Figure 2 As shown;

[0033] S23, repeating steps S21-S22, and continuously resampling and converting the Manchester II type biphase level code sequence to be transmitted;

[0034] S24, output the data bits after resampling and conversion to step S3.

[0035] The power carrier communication physical layer of step S3 includes two parts: the transmitter and the receiver. At the transmitter, it is responsible for OFDM modulating the data generated in step S2 and coupling the signal to the power line for transmission. At the receiver, the physical layer demodulates the signal received from the power line through OFDM, recovers the communication data and submits it to step S2. Figure 3 , the specific steps include:

[0036] The steps of the power carrier communication physical layer transmitter are as follows:

[0037] 1) receiving the resampled and converted data bit sequence output from process 2;

[0038] 2) FEC (forward error correction) encoding and interleaving of data bits;

[0039] 3) Send a leading character;

[0040] 4) Insert pilot signal;

[0041] 5) IFFT (Inverse Fast Fourier Transform) operation;

[0042] 6) Insert CP (cyclic prefix);

[0043] 7) Windowing and shaping filtering;

[0044] 8) DAC conversion (digital-to-analog conversion);

[0045] 9) The signal generated by the DAC is coupled to the power line for transmission through the PLC (power line carrier communication) analog front end.

[0046] The steps of the power carrier communication physical layer receiving end are:

[0047] 1) Start the PLC analog front end, collect the signal on the power line and perform ADC conversion (analog-to-digital conversion);

[0048] 2) Synchronous detection and CP stripping;

[0049] 3) FFT and channel estimation;

[0050] 4) De-interleaving.

[0051] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art of the present invention, several equivalent substitutions or obvious variations can be made without departing from the concept of the present invention, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for implementing a 1553B bus communication protocol via a power line, characterized in that: The steps include: S1. Group the communication data to be transmitted according to the 1553B bus communication protocol and generate corresponding words, and assemble them into more complex messages and frame structures with words as basic units; Then, the word is taken as the smallest encoding object, and each word is encoded into the Manchester II type biphase level code form; S2, sampling the Manchester II biphase level code of each bit time at a double rate, and generating 2 data bits of corresponding level polarity according to the polarity of the level of the first 1 / 2 bit time and the second 1 / 2 bit time; S3, using orthogonal frequency division multiplexing technology to realize the physical layer of power carrier communication, and transmit data bits on the power line by coupling with the power line; Step S1 specifically includes: S11, grouping every 16 bits of data to be transmitted into a group as valid bits; S12, performing parity check on the 16-bit data to generate 1 parity check bit; S13, a total of 17 data generated in steps S11 and S12 are encoded with Manchester II type biphase level code; S14, generating a corresponding type of synchronization header according to the specific attributes of the transmission data, each synchronization header is composed of a level code of a specific shape of two bits but occupying three bits; S15, assembling the synchronization header, valid bit and parity check bit encoded by Manchester II type biphase level code into words, each word occupies 20 bits in total; S16. Repeat steps S11 to S15 to assemble several characters into a message with richer content, and further assemble several messages into a frame.

2. The method for implementing the 1553B bus communication protocol through a power line according to claim 1, characterized in that: Step S2 specifically includes: S21, taking a word as a basic unit, reading a Manchester II type biphase level code sequence when 20 bits are read; S22, taking 1 / 2 bit time as a sampling unit, re-sampling the Manchester biphase level code of each bit time into two independent levels connected one after the other, and converting the level polarity information into corresponding data bits; S23, repeating steps S21-S22, and continuously resampling and converting the Manchester II type bi-phase level code sequence to be transmitted.

3. The method for implementing the 1553B bus communication protocol through a power line as claimed in claim 1, characterized in that: The physical layer described in step S3 is responsible for OFDM modulation of the data generated in step S2 in the transmission direction, and coupling the signal to the power line for transmission; In the receiving direction, the physical layer demodulates the signal received from the power line via OFDM, recovers the communication data and feeds it back to step S2.

4. The method for implementing 1553B bus communication protocol through power line according to claim 3, characterized in that: The process of the physical layer transmitter in step S3 is: A1, receiving the data bit sequence after re-sampling and conversion output from step S2; A2, forward error correction coding and interleaving of data bits; A3, send the leading character; A4, insert pilot; A5, IFFT operation; A6, insert cyclic prefix; A7, windowing and shaping filtering; A8, DAC conversion; A9, couple the signal generated by DAC to the power line for transmission through the PLC analog front end; The process of the physical layer receiving end in step S3 is: B1. Start the PLC analog front end, collect the signal on the power line and perform ADC conversion; B2, synchronous detection and stripping of cyclic prefix; B3, FFT operation and channel estimation; B4, de-interlacing; B5. Feedback the deinterleaved data output to step S2.

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