CN104243084B - Error correction coding/decoding method and its device applied to human body communication channel - Google Patents

Abstract

The invention relates to an error correction encoding and decoding method applied to a human body communication channel, which comprises the following steps in turn: performing BCH encoding on an input data stream; performing insertion synchronization status word processing on the BCH encoded data stream; Perform random packet interleaving encoding on the data stream after word processing; modulate the data stream after random packet interleaving encoding; transmit the modulated data stream through the human body communication channel; receive and decode the data stream transmitted by the human body communication channel tune; detect the synchronization status word of the demodulated data stream; deinterleave the data stream after the synchronization status word detection; perform BCH decoding and output the deinterleaved data stream. The error correction encoding and decoding method applied to the human body communication channel meets the requirements for correcting random errors and burst errors. In addition, it also provides an error correction coding and decoding device applied to the communication channel of the human body, which can correct random errors and burst errors.

Description

Error correction coding and decoding method and device applied to human body communication channel

technical field

The invention relates to the field of wireless body area networks, in particular to an error correction encoding and decoding method and device applied to human body communication channels.

Background technique

With the rapid development of modern science and technology, digital communication has penetrated into all aspects of human social life. In order to meet various application requirements, various new communication methods emerge in an endless stream. Human body communication is a new type of wireless communication that uses the human body as a signal transmission medium. No matter in the field of medical health or daily work and life, human body communication has broad application prospects. However, due to changes in human motion and application environment, not only random errors but also burst errors may occur during the transmission of signals in the human body communication channel. These errors in the transmission process will seriously affect the communication quality of human body communication. Therefore, how to design a baseband system suitable for human body communication to ensure the validity and reliability of information has become an urgent problem to be solved.

Wireless Body Area Network (BAN) is a sensor network near the human body, which consists of some sensor nodes with communication functions and a body master station (or BAN coordinator). In 2012, the specification standard IEEE (Institute of Electrical and Electronics Engineers, Institute of Electrical and Electronics Engineers) 802.15.6 of the wireless body area network was promulgated. Human Body Communication (HBC) technology, as one of the physical layer technologies of wireless body area network, has attracted more and more attention. Early human body communication systems were relatively simple, and some did not even have coding error correction capabilities. With the more extensive and complex applications, more and more attention has been paid to the related work of channel error correction coding. At present, the mainstream codes in channel error correction coding include BCH code (BCH code is taken from the abbreviation of Bose, Ray-Chaudhuri and Hocquenghem, which is a coding method that has been studied more in coding theory, especially in error correction codes), RS code (Reed-solomon codes, Reed-solomon codes), convolutional codes, Turbo codes (Turbo codes are a class of applications in satellite communications in outer space and designers seek to achieve maximum information transmission over a bandwidth-limited communication link in the face of data-destroying noise High-performance error-correcting codes for other wireless communication applications) and LDPC codes (Low Density Parity Check Code, Low Density Parity Check Code), etc. Various codes have their different applications. The channel coding of the physical layer of the body area network mostly adopts common BCH codes. BCH code is a good linear block code. However, the existing BCH coding technology used in human body communication channels can only have a good error correction ability for random errors, and cannot meet the requirements for burst error correction.

Contents of the invention

Based on this, it is necessary to provide an error correction encoding and decoding method and its device applied to human body communication channels, which can meet the requirements for correcting random errors and burst errors at the same time.

An error correction encoding and decoding method applied to a human body communication channel, comprising the following steps in sequence:

BCH encode the input data stream;

Insert synchronization status word processing on the data stream encoded by BCH;

Perform random packet interleaving encoding on the data stream processed by inserting the synchronization status word;

Modulate the data stream after random packet interleaving and coding;

Transmit the modulated data stream through the human body communication channel;

Receive and demodulate the data stream transmitted by the human body communication channel;

Detecting the synchronization status word of the demodulated data stream;

Deinterleave the data stream after the synchronization status word detection process;

Perform BCH decoding on the deinterleaved data stream and output it.

In one of the embodiments, in the step of performing BCH encoding on the input data stream, the input data is encoded in a parallel synchronous encoding manner.

In one of the embodiments, before the step of performing BCH encoding on the input data stream, the following steps are also included:

An input data stream is received and stored in a buffer.

In one of the embodiments, in the step of modulating the data stream encoded by random block interleaving, BPSK modulation is used to modulate the data stream encoded by random block interleaving; In the step of demodulating the data stream transmitted by the channel, the data stream transmitted by the human body communication channel is demodulated by using the BPSK demodulation method.

In one embodiment, in the step of BCH decoding and outputting the deinterleaved data stream, the data stream obtained through BCH decoding is output according to a first-in-first-out rule.

An error correction encoding and decoding device applied to a human body communication channel, comprising a sequentially connected BCH encoder, an insertion synchronization status word module, a random packet interleaver, a modulator, a demodulator, a synchronization status word detector, and a deinterleaver And a BCH decoder, the BCH encoder performs BCH encoding on the input data stream, the insertion synchronization status word module performs insertion synchronization status word processing on the data stream after BCH encoding, and the random packet interleaver performs insertion synchronization status word processing on the input data stream. The data stream processed by the state word is subjected to random block interleaving encoding, the modulator modulates the data stream after random block interleaving encoding, and the modulated data stream is transmitted through the human body communication channel, and the demodulator receives The data stream transmitted by the communication channel is demodulated, the synchronization status word detector detects the synchronization status word of the demodulated data stream, and the deinterleaver deinterleaves the data stream after the synchronization status word detection process , the BCH decoder performs BCH decoding on the deinterleaved data stream.

In one of the embodiments, the error correction coding and decoding device applied to the human body communication channel further includes a controller, and the BCH encoder includes 32 BCH coding branches, and the 32 BCH coding branches are connected in parallel , the controllers are respectively connected to 32 BCH encoding branches, under the control of the controller, the 32 BCH encoding branches use the same clock and reset signal, and the 32 BCH encoding branches are independent The insertion synchronization status word module is connected in series, and the controller is respectively connected to the insertion synchronization status word modules connected in series on the 32 BCH encoding branches. Under the control of the controller, the insertion synchronization status word module is The data stream output by each BCH coding branch is inserted into the synchronization status word.

In one of the embodiments, the error correction codec device applied to the human body communication channel further includes a buffer, the buffer is connected to the input end of the BCH encoder, and the buffer is used to receive input data and convert it to storage.

In one of the embodiments, the modulator and the demodulator are respectively a BPSK modulator and a BPSK demodulator, and the BPSK modulator performs BPSK modulation on the data stream after random block interleaving encoding, and the BPSK demodulator The device performs BPSK demodulation on the data stream transmitted by the human body communication channel.

In one embodiment, the output end of the BCH decoder is connected to a FIFO data buffer, and the FIFO data buffer sequentially outputs the output data according to the sequence of data input.

The above-mentioned error correction coding and decoding method applied to the human body communication channel performs BCH coding and random block interleaving coding on the input data stream, and then performs corresponding decoding on the data stream, wherein BCH coding on the input data stream has a good correction effect on random errors Error capability, and random block interleaving coding has a good error correction ability for burst errors, so the error correction coding and decoding method applied to the human body communication channel meets the requirements for random error and burst error correction at the same time. In addition, it also provides an error correction coding and decoding device applied to the communication channel of the human body, which can not only correct random errors, but also correct burst errors.

Description of drawings

Fig. 1 is a flow chart of an embodiment of an error correction encoding and decoding method applied to a human body communication channel;

Fig. 2 is a schematic structural diagram of an embodiment of an error correction codec device applied to a human body communication channel;

Fig. 3 is a schematic structural diagram of a BCH encoder of an embodiment.

Detailed ways

In order to solve the problem that the BCH coding technology currently used in human body communication channels can only have good error correction capabilities for random errors, but cannot effectively correct burst errors, this embodiment provides a method for human body communication channels. Error correction codec method. The error correction coding and decoding method applied to the human body communication channel will be specifically described below in combination with specific embodiments.

Please refer to FIG. 1, the error correction coding and decoding method applied to the human body communication channel provided by this embodiment includes the following steps:

Step S100: Receive an input data stream and store the input data stream in a buffer. The buffer is used to temporarily store the input data stream, without real-time processing of the input data stream, and can delay processing the input data stream according to actual needs.

Step S110: Perform BCH encoding on the input data stream. In this embodiment, in step S110, the input data stream is encoded using a parallel synchronous encoding method. The parallel synchronous encoding method can reduce the encoding and decoding cycle and improve the encoding efficiency.

Step S120: Inserting a synchronization status word into the BCH-encoded data stream. The function of inserting the synchronous status word is to keep the synchronization of the data flow and avoid the loss of the data flow.

Step S130: Perform random block interleaving coding on the data stream processed by inserting the synchronization status word. In the communication process, due to external interference or channel fading of the human body communication channel, long burst errors may occur. Random block interleaving coding can be used to discretize the errors, and the receiving end uses the coding technology to correct random errors to eliminate random errors. errors, which can improve the transmission quality of the signal.

Step S140: Modulate the data stream encoded by random block interleaving. Generally speaking, the information of the signal source (also known as the source) contains a DC component and a lower frequency component, called the baseband signal. The baseband signal often cannot be directly transmitted in the channel as a transmission signal, so the baseband signal must be converted into a signal with a very high frequency relative to the baseband frequency to be suitable for transmission in the channel. In this embodiment, the BPSK (Binary Phase Shift Keying, Binary Phase Shift Keying) modulation method is used to perform BPSK modulation on the data stream after random block interleaving coding, so that the data stream after random block interleaving coding is suitable for human body transmitted in the communication channel.

Step S150: Transmit the modulated data stream through the human body communication channel.

Step S160: Receive and demodulate the data stream transmitted by the human body communication channel. In this embodiment, the data stream transmitted by the human body communication channel is a BPSK data stream, so the BPSK demodulation method is used to demodulate the BPSK data stream.

Step S170: Detect the synchronization status word of the demodulated data stream.

Step S180: Perform deinterleaving on the data stream after the synchronization status word detection process.

Step S190: Perform BCH decoding on the deinterleaved data stream and output it.

The above-mentioned error correction coding and decoding method applied to the human body communication channel performs BCH coding and random block interleaving coding on the input data stream, and then performs corresponding decoding on the data stream, wherein BCH coding on the input data stream has a good correction effect on random errors Error capability, and random block interleaving coding has a good error correction ability for burst errors, so the error correction coding and decoding method applied to the human body communication channel meets the requirements for random error and burst error correction at the same time.

Using the above error correction codec method applied to the human body communication channel, this embodiment also provides an error correction codec device applied to the human body communication channel. Please refer to Fig. 2, the error correction coding and decoding device applied to the human body communication channel includes a buffer 210, a BCH encoder 220, an insertion synchronization status word module 230, a random packet interleaver 240, a BPSK modulator 250, a BPSK demodulator 260, Sync status word detector 270 , de-interleaver 280 and BCH decoder 290 .

The buffer 210, the BCH encoder 220, the module for inserting the synchronization status word 230, the random packet interleaver 240, and the BPSK modulator 250 are sequentially connected in series. The output end of the BPSK modulator 250 is connected to the human body communication channel. The input data is input from the buffer 210, passes through the BCH encoder 220, inserts the synchronization status word module 230, the random block interleaver 240 and the BPSK modulator 250 in sequence and enters the human body communication channel. Among them, the buffer 210 is used to receive and store the input data stream. The BCH encoder 220 performs BCH encoding on the input data stream. The insertion synchronization status word module 230 performs insertion synchronization status word processing on the BCH-encoded data stream to maintain the synchronization of the data stream and avoid loss of the data stream. The random block interleaver 240 performs random block interleaving coding on the data stream processed by inserting the synchronization status word. The data stream encoded by random block interleaving is then modulated by the BPSK modulator 250, and the obtained BPSK data stream enters the human body communication channel.

Please refer to FIG. 3 , the error correction codec device applied to the human body communication channel further includes a controller 300 . The BCH encoder 220 includes 32 BCH encoding branches. The 32 BCH encoding branches are connected in parallel. The controller 300 is respectively connected to the 32 BCH encoding branches. Under the control of the controller 300, the 32 BCH encoding branches use the same clock and reset signal, thereby reducing the encoding and decoding cycle and improving the encoding efficiency. In addition, the 32 BCH encoding branches are all connected in series with a synchronization status word insertion module 230 . The controller 300 is respectively connected to the insertion synchronization status word modules 230 connected in series on the 32 BCH encoding branches. Under the control of the controller 300, the insertion synchronization status word module 230 inserts Synchronization status word.

BPSK demodulator 260, sync status word detector 270, de-interleaver 280 and BCH decoder 290 are sequentially connected in series. The input end of the BPSK demodulator 260 is connected to the human body communication channel. The BPSK data stream transmitted by the human body communication channel passes through the BPSK demodulator 260 , the sync status word detector 270 , the deinterleaver 280 and the BCH decoder 290 in sequence. Among them, the BPSK demodulator 260, the synchronization status word detector 270, the deinterleaver 280 and the BCH decoder 290 are used to decode the BPSK data stream to obtain output data. In this embodiment, the output end of the BCH decoder 290 is connected to a FIFO (First Input First Output, First In First Out) data buffer. The FIFO data buffer sequentially outputs data according to the sequence of data input.

The following briefly introduces the BCH decoding process of the BCH decoder 290 on the deinterleaved data stream. The data flow at the input of the BCH decoder 290 is defined as the reception polynomial r(x). The decoding step of the BCH decoder 290 for the data stream is to calculate the syndrome S=(S ₁ , S ₂ ..., S _2t ) from the receiving polynomial r(x). If S=0, it means that the received information is the same as the transmitted information, and there is no Error, there is no need to iteratively solve the error location polynomial. If S≠0, the error position polynomial σ(X) is determined through the syndrome components S ₁ , S ₂ ..., S _2t . Find the root of σ(X), that is, determine the number of error positions β ₁ , β ₂ ... β _v , and correct the errors in r(x). Let the sending code be v(x), e(x) is the error mode, so r(x)=v(x)+e(x). Because α ¹ , α ² ,…, α ^2t are the roots of generating polynomials.

S _i ＝r(α)＝r ₀ +r ₁ α ⁱ +r ₂ α ²ⁱ +…+r _n-1 α ^(n-1)i ＝(…((r _n-1 α ⁱ +r _n-2 )α ⁱ +r _n-3 )α ⁱ +…)α ⁱ +r ₀ (1)

From the formula (1), the hardware circuit for calculating the syndrome S can be easily obtained.

The key to BCH code decoding is to determine the error location polynomial σ(X). The BCH decoding designed this time uses the riBM algorithm optimized on the common error polynomial BM (Boyer-Moore) algorithm. No inverse is required, the hardware structure is simplified, and the required iterations are half of the original algorithm. The optimized pseudocode is as follows:

Among them, B ^(j) is a temporary error location polynomial register, and l(j+1) represents the highest term coefficient of σ ^(j+1) (x).

In this embodiment, in the BCH encoding step, the BCH (31, 19, 2) code with a code length of 31 and an information bit of 19 is obtained, and the BCH (31, 19, 2) code is the original BCH (63, 51, 2) Shortcodes. The shortened length is 32, that is, 32 0s need to be added in front to become a BCH (63, 51, 2) code. Therefore, when looking for the error position, you should start from the 32nd position, and you only need to replace α ⁱ with α ⁱ⁺³² when searching. In the initial state, σ ₀ , α ³² σ ₁ , α ^(32*2)%63 σ ₂ , that is, σ ₀ , α ³² σ ₁ , α ¹ σ ₂ are loaded into the register. The final result c(x) is the corrected data.

In the above-mentioned error correction codec device applied to the human body communication channel, the BCH encoder 220 and the random block interleaver 240 successively perform BCH encoding and random block interleaving encoding on the input data, and then pass the deinterleaver 280 and the BCH decoder 290 to the signal By decoding, not only random errors can be corrected, but burst errors can also be corrected.

In addition, the improved inversion-free riBM algorithm requires fewer iterations and is faster than the original BM algorithm. And because the random group interleaving technology is adopted, the random numbers generated each time are different. The transmission in the human body communication channel is equivalent to playing the role of encryption, which greatly improves the security of information.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (8)

1. An error correction encoding and decoding method applied to a human body communication channel, characterized in that it comprises the following steps successively: BCH encode the input data stream; Insert synchronization status word processing on the data stream encoded by BCH; Perform random packet interleaving encoding on the data stream processed by inserting the synchronization status word; Modulate the data stream after random packet interleaving and encoding; Transmit the modulated data stream through the human body communication channel; Receive and demodulate the data stream transmitted by the human body communication channel; Detecting the synchronization status word of the demodulated data stream; Deinterleave the data stream after the synchronization status word detection process; Perform BCH decoding on the deinterleaved data stream and output it; Before the step of carrying out BCH encoding to the input data stream, the following steps are also included: receiving the input data stream and storing the input data stream in a buffer so as to obtain the input data stream from the buffer for BCH encoding; The BCH decoding adopts the riBM algorithm after optimizing the common error polynomial BM algorithm. 2. The error correction encoding and decoding method applied to human body communication channels according to claim 1, characterized in that, in the step of performing BCH encoding on the input data stream, the input data is encoded by using parallel synchronous encoding. 3. The error correction encoding and decoding method applied to human body communication channels according to claim 1, characterized in that, in the step of modulating the data stream after random block interleaving encoding, the BPSK modulation method is used to The coded data stream is modulated by random packet interleaving; in the step of receiving and demodulating the data stream transmitted by the human body communication channel, the data stream transmitted by the human body communication channel is demodulated by using BPSK demodulation method. 4. The error correction coding and decoding method applied to human body communication channels according to claim 1, characterized in that, in the step of BCH decoding and outputting the deinterleaved data stream, the BCH decoding obtained Data streams are output according to the first-in-first-out rule. 5. An error correction encoding and decoding device applied to human body communication channels, characterized in that it comprises a BCH encoder connected sequentially, an insertion synchronization status word module, a random packet interleaver, a modulator, a demodulator, and a synchronization status word detector, deinterleaver and BCH decoder, the BCH encoder performs BCH encoding on the input data stream, the insertion synchronization status word module inserts synchronization status word processing on the data stream after BCH encoding, and the random grouping The interleaver performs random packet interleaving coding on the data stream processed by inserting the synchronization status word, the modulator modulates the data stream after random packet interleaving coding, and the modulated data stream is transmitted through the human body communication channel, and the The demodulator receives and demodulates the data stream transmitted by the human body communication channel, the synchronization status word detector detects the synchronization status word of the demodulated data stream, and the deinterleaver detects and processes the synchronization status word Deinterleaving is performed on the data stream, and the BCH decoder performs BCH decoding on the deinterleaved data stream; the error correction codec device applied to the human body communication channel also includes a buffer, and the buffer is connected to the BCH The input end of the encoder is connected, and the buffer is used to receive the input data stream and store it, so as to obtain the input data stream from the buffer for BCH encoding; The BCH decoding adopts the riBM algorithm after optimizing the common error polynomial BM algorithm. 6. The error correction codec device applied to the human body communication channel according to claim 5, wherein the error correction codec device applied to the human body communication channel also includes a controller, and the BCH encoder includes 32 BCH coding branches, the 32 BCH coding branches are connected in parallel, the controllers are respectively connected to the 32 BCH coding branches, under the control of the controller, the 32 BCH coding branches Using the same clock and reset signal, the 32 BCH coding branches are independently connected in series with the insertion synchronization status word modules, and the controllers are respectively connected to the insertion synchronization status word modules connected in series on the 32 BCH coding branches , under the control of the controller, the inserting synchronization status word module inserts a synchronization status word for the data stream output by each BCH encoding branch. 7. the error correction codec device that is applied to human body communication channel according to claim 5, is characterized in that, described modulator and demodulator are respectively BPSK modulator and BPSK demodulator, and described BPSK modulator is to BPSK modulation is performed on the data stream after the random packet interleaving and encoding, and the BPSK demodulator performs BPSK demodulation on the data stream transmitted by the human body communication channel. 8. The error correction codec device applied to human body communication channel according to claim 5, characterized in that, the output end of the BCH decoder is connected with a FIFO data buffer, and the FIFO data buffer is input according to the data input Output the output data sequentially.