A transmitting method of turbo code for frequency hopping system

Abstract

This invention discloses a method for transmitting Turbo codes in a frequency-hopping system, relating to the field of anti-interference communication technology. The method includes: first, performing Turbo encoding on an information sequence to generate a system sequence and a parity sequence; then, sending the system sequence and parity sequence to different interleavers to obtain interleaved system and parity sequences; then, multiplexing the interleaved system and parity sequences to obtain a transmission sequence; then, dividing the transmission sequence into blocks; finally, distributing the block data to each frequency-hopping pulse, completing modulation, and transmitting according to the frequency-hopping system frame structure. This invention can improve the correct reception rate of system communication frames under partial frequency band interference and time-domain pulse interference, thereby achieving better anti-interference performance.

Description

Technical Field

[0001] This invention relates to the field of anti-interference communication technology, and specifically to a method for transmitting Turbo codes in a frequency hopping system. Background Technology

[0002] The statements in this section are provided only as background information in relation to this disclosure and may not constitute prior art.

[0003] Frequency hopping communication technology continuously changes frequency according to a frequency hopping pattern, which makes its anti-interference, anti-interception, and networking capabilities outstanding. Given the high requirements for the security and confidentiality of transmitted information in communication systems, frequency hopping technology is widely used in anti-interference communication systems. In frequency hopping communication systems, error control is essential, especially in the field of anti-interference communication where security and effectiveness are highly valued.

[0004] Forward error correction (FEC) is the process of detecting and correcting errors in information at the receiving end. Turbo codes are a type of high-performance forward error correction code. Under a specific signal-to-noise ratio, Turbo codes can communicate at a transmission rate close to the theoretical value. Turbo codes are widely used in 3G and 4G communication systems (e.g., UMTS and LTE) as well as in other applications such as deep space communication.

[0005] Error-correcting codes have poor error correction performance for burst errors in the channel. Therefore, interleaving techniques are usually used in error-correcting coding to randomize burst errors. In conventional frequency-hopping communication systems, the data after Turbo error correction coding is interleaved, and the data is distributed to frequency-hopping pulses of different frequencies through permutation and combination. This transforms the channel into an approximately memoryless channel, giving full play to the error correction capability of the channel coding. However, for practical frequency-hopping systems, there are often partial frequency band interference and time-domain pulse interference. To improve its anti-interference performance, the system bits and parity bits after Turbo coding need to be randomly and evenly distributed to each frequency-hopping pulse. This ensures that under partial frequency band interference and time-domain pulse interference, the coded system bits and parity bits retained on the uninterrupted frequency-hopping pulses are as balanced as possible to obtain the maximum error correction and anti-interference capability.

[0006] Figure 2a and Figure 2b Typical schematic diagrams of frequency-hopping communication systems under partial frequency band interference and time-domain pulse interference are given; among them, Figure 2a It is partial frequency band interference, and the set of frequency hopping points is {F1 F2 ... F}. N If one or more interference signals exist in the frequency band of frequency hopping communication, the power of the interference signal is much greater than the power of the signal in the interference band. The frequency hopping system can only recover the source information through the undisturbed frequency hopping signal. Figure 2bIt is time-domain pulse interference. In a single frequency hopping transmission, the number of frequency hopping pulses is N. Among them, some pulse signals are affected by pulse interference. During the interference time, the power of the interference signal is much greater than the power of the signal. The frequency hopping system can only recover the source information through the uninterrupted frequency hopping signal. Summary of the Invention

[0007] The purpose of this invention is to address the problem that, in practical frequency hopping systems, under partial frequency band interference and time-domain pulse interference, the interference signal power is much greater than the signal power, and the frequency hopping system can only recover the source information through the undisturbed frequency hopping signal, resulting in generally poor anti-interference performance. This invention provides a method for transmitting Turbo codes in frequency hopping systems, which can improve the correct reception rate of system communication frames under partial frequency band interference and time-domain pulse interference, thereby achieving better anti-interference performance and solving the aforementioned problems.

[0008] The technical solution of the present invention is as follows:

[0009] A method for transmitting Turbo codes in a frequency hopping system, specifically including the following steps:

[0010] Step S1: For the information sequence {x} k} Perform Turbo encoding to generate the system sequence {x} k}、Verification sequence {y i,k} and check sequence {z i,k};

[0011] Step S2: Set the system sequence {x} k}、Verification sequence {y i,k} and check sequence {z i,k The data are fed into different interleavers to obtain the interleaved system sequence {x′}. k}、Verification sequence {y′ i,k} and check sequence {z′ i,k};

[0012] Step S3: Transform the system sequence {x′} k}、Verification sequence {y′ i,k} and check sequence {z′ i,k Perform data multiplexing to obtain the transmission sequence;

[0013] Step S4: Divide the transmission sequence into blocks, namely block 1, block 2... block N, with the number of bits in each block corresponding to the number of bits transmitted by one frequency modulation pulse;

[0014] Step S5: Distribute the block data to each frequency hopping pulse, complete the modulation, and send it according to the frequency hopping system frame structure.

[0015] Further, step S1 includes:

[0016] Information sequence {x} of length K k The data is fed into N component encoders for encoding, and outputs N sets of check sequences as {y}. i,k It should be noted that: x k ∈{0,1}, 0≤k≤K-1, 0≤i≤N-1, where N is the number of component encoders in the encoder;

[0017] {x k It is also output as a system sequence.

[0018] At the same time, {x k The sequence after interleavering is fed into N component encoders for encoding, outputting N sets of check sequences as {z}. i,k It should be noted that: z i,k ∈{0,1}, 1≤i≤N, 0≤k≤K-1;

[0019] {x k}, {y i,k},{z i,k All sequences are of length K, and there are a total of 2N+1 groups.

[0020] Further, step S2 includes:

[0021] The system sequence {x k}、Verification sequence {y i,k} and check sequence {z i,k Given 2N+1 sequences, each sequence is fed into one of 2N+1 interleavers, which resets the positions of the elements in the sequence. Each interleaver has a depth of K, and the resulting sequence is the system sequence {x′}. k}、Verification sequence {y′ i,k} and check sequence {z′ i,k}

[0022] Further, step S3 includes:

[0023] The interleaved system sequence {x′ k}、Verification sequence {y′ i,k} and check sequence {z′ i,k}, input matrices of dimension (2N+1)×K sequentially, and implement data multiplexing by writing rows and reading columns; that is, when inputting matrices, {x′ k Input the first line, {y′ 1,k Input the second line, {y′ 2,k Enter the 3rd line...{y′ N,k Input the (N+1)th line; {z′ 1,k Input the (N+2)th line, {z′ 2,k Input the (N+3)th line...{z′ N,kInput the 2N+1th line; when reading the matrix, read the matrix elements column by column to obtain the sending sequence x′0, y′ 1,0 ,y′ 2,0 …y′ N,0 ,z′ 1,0 ,z′ 2,0 …z′ N,0 ,x′1,y′ 1,1 ,y′ 2,1 …y′ N,1 ,z′ 1,1 ,z′ 2,1 …z′ N,1 ,…,x′ K-1 ,y′ 1,K-1 ,y′ 2,K-1 …y′ N,K-1 ,z′ 1,K-1 ,z′ 2,K-1 …z′ N,K-1 The total length of the transmitted sequence is (2N+1)×K.

[0024] Further, step S4 includes:

[0025] In a frequency hopping system, each frequency hopping pulse carries P coded bits, and the number of frequency hopping pulses in a frequency hopping frame is M. Then, the total number of bits transmitted in a frequency hopping frame is PM.

[0026] In the design of a frequency hopping system, the length of the transmission sequence output in step S3 is equal to the total number of bits transmitted in a frequency hopping frame, i.e. (2N+1)×K=PM;

[0027] The transmission sequence output in step S3 is divided into groups of P bits each, namely block 1, block 2... block M.

[0028] Furthermore, in step S4:

[0029] When the length of the transmission sequence output in step S3 is less than the total number of bits transmitted in a frequency hopping frame, i.e. (2N+1)×K≤PM, Q fixed bits are added after (2N+1)×K bits of the transmission sequence, or the first Q bits of the transmission sequence are added, so that (2N+1)×K+Q=PM. Then, these PM bits of data are divided into groups of P bits each, namely block 1, block 2... block M.

[0030] Further, step S4 includes:

[0031] The data bits in the blocks are assigned to the corresponding frequency hopping pulses, i.e., block 1 is assigned to frequency hopping pulse 1, block 2 is assigned to frequency hopping pulse 2, ... block M is assigned to frequency hopping pulse M;

[0032] Each hop bit information is modulated, and the frequency synthesizer is controlled according to the frequency pattern of the frequency hopping pulse. Then, signals such as synchronization segment and frequency switching segment are added to send out the frequency hopping signal.

[0033] Compared with existing technologies, the advantages of this invention are:

[0034] A method for transmitting Turbo codes in a frequency-hopping system includes: performing Turbo encoding on an information sequence to generate a system sequence and a parity sequence; then feeding the system sequence and parity sequence into different interleavers to obtain interleaved system sequences and parity sequences; then multiplexing the interleaved system sequence and parity sequence to obtain a transmission sequence; then dividing the transmission sequence into blocks; finally, distributing the block data to each frequency-hopping pulse, completing modulation, and transmitting according to the frequency-hopping system frame structure; this method can improve the correct reception rate of system communication frames under interference in some frequency bands and time-domain pulse interference, thereby achieving better anti-interference performance. Attached Figure Description

[0035] Figure 1 A flowchart illustrating a method for transmitting Turbo codes in a frequency hopping system;

[0036] Figure 2a This is a schematic diagram of interference in some frequency bands;

[0037] Figure 2b This is a schematic diagram of partial time-domain pulse interference;

[0038] Figure 3 This is a schematic diagram illustrating a transmission example of a Turbo code in a frequency hopping system with a 1 / 3 code rate. Detailed Implementation

[0039] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0041] Example 1

[0042] Error-correcting codes have poor error correction performance for burst errors in the channel. Therefore, interleaving techniques are usually used in error-correcting coding to randomize burst errors. In conventional frequency-hopping communication systems, the data after Turbo error correction coding is interleaved, and the data is distributed to frequency-hopping pulses of different frequencies through permutation and combination. This transforms the channel into an approximately memoryless channel, giving full play to the error correction capability of the channel coding. However, for practical frequency-hopping systems, there are often partial frequency band interference and time-domain pulse interference. To improve its anti-interference performance, the system bits and parity bits after Turbo coding need to be randomly and evenly distributed to each frequency-hopping pulse. This ensures that under partial frequency band interference and time-domain pulse interference, the coded system bits and parity bits retained on the uninterrupted frequency-hopping pulses are as balanced as possible to obtain the maximum error correction and anti-interference capability.

[0043] Figure 2a and Figure 2b Typical schematic diagrams of frequency-hopping communication systems under partial frequency band interference and time-domain pulse interference are given; among them, Figure 2a It is partial frequency band interference, and the set of frequency hopping points is {F1 F2 ... F}. N If one or more interference signals exist in the frequency band of frequency hopping communication, the power of the interference signal is much greater than the power of the signal in the interference band. The frequency hopping system can only recover the source information through the undisturbed frequency hopping signal. Figure 2b It is time-domain pulse interference. In a single frequency hopping transmission, the number of frequency hopping pulses is N. Among them, some pulse signals are affected by pulse interference. During the interference time, the power of the interference signal is much greater than the power of the signal. The frequency hopping system can only recover the source information through the uninterrupted frequency hopping signal.

[0044] This embodiment addresses the aforementioned problems by proposing a method for transmitting Turbo codes in a frequency hopping system. This method can improve the correct reception rate of system communication frames under interference in some frequency bands and time-domain pulse interference, thereby achieving better anti-interference performance.

[0045] Please see Figure 1 A method for transmitting Turbo codes in a frequency hopping system, specifically including the following steps:

[0046] Step S1: For the information sequence {x} k} Perform Turbo encoding to generate the system sequence {x} k}、Verification sequence {y i,k} and check sequence {z i,k};

[0047] Step S2: Set the system sequence {x} k}、Verification sequence {y i,k} and check sequence {z i,k The data are fed into different interleavers to obtain the interleaved system sequence {x′}.k}、Verification sequence {y′ i,k} and check sequence {z′ i,k};

[0048] Step S3: Transform the system sequence {x′} k}、Verification sequence {y′ i,k} and check sequence {z′ i,k Perform data multiplexing to obtain the transmission sequence;

[0049] Step S4: Divide the transmission sequence into blocks, namely block 1, block 2... block N, with the number of bits in each block corresponding to the number of bits transmitted by one frequency modulation pulse;

[0050] Step S5: Distribute the block data to each frequency hopping pulse, complete the modulation, and send it according to the frequency hopping system frame structure.

[0051] In this embodiment, specifically, step S1 includes:

[0052] Information sequence {x} of length K k The data is fed into N component encoders for encoding, and outputs N sets of check sequences as {y}. i,k It should be noted that: x k ∈{0,1}, 0≤k≤K-1, 0≤i≤N-1, where N is the number of component encoders in the encoder;

[0053] {x k It is also output as a system sequence.

[0054] At the same time, {x k The sequence after interleavering is fed into N component encoders for encoding, outputting N sets of check sequences as {z}. i,k It should be noted that: z i,k ∈{0,1}, 1≤i≤N, 0≤k≤K-1;

[0055] {x k}, {y i,k},{z i,k All sequences are of length K, and there are a total of 2N+1 groups.

[0056] In this embodiment, specifically, step S2 includes:

[0057] The system sequence {x k}、Verification sequence {y i,k} and check sequence {z i,k Given 2N+1 sequences, each sequence is fed into one of 2N+1 interleavers, which resets the positions of the elements in the sequence. Each interleaver has a depth of K, and the resulting sequence is the system sequence {x′}. k}、Verification sequence {y′ i,k} and check sequence {z′ i,k}

[0058] In this embodiment, specifically, step S3 includes:

[0059] The interleaved system sequence {x′ k}、Verification sequence {y′ i,k} and check sequence {z′ i,k}, input matrices of dimension (2N+1)×K sequentially, and implement data multiplexing by writing rows and reading columns; that is, when inputting matrices, {x′ k Input the first line, {y′ 1,k Input the second line, {y′ 2,k Enter the 3rd line...{y′ N,k Input the (N+1)th line; {z′ 1,k Input the (N+2)th line, {z′ 2,k Input the (N+3)th line...{z′ N,k Input the 2N+1th line; when reading the matrix, read the matrix elements column by column to obtain the sending sequence x′0, y′ 1,0 ,y′ 2,0 …y′ N,0 ,z′ 1,0 ,z′ 2,0 …z′ N,0 ,x′1,y′ 1,1 ,y′ 2,1 …y′ N,1 ,z′ 1,1 ,z′ 2,1 …z′ N,1 ,…,x′ K-1 ,y′ 1,K-1 ,y′ 2,K-1 …y′ N,K-1 ,z′ 1,K-1 ,z′ 2,K-1 …z′ N,K-1 The total length of the transmitted sequence is (2N+1)×K.

[0060] In this embodiment, specifically, step S4 includes:

[0061] In a frequency hopping system, each frequency hopping pulse carries P coded bits, and the number of frequency hopping pulses in a frequency hopping frame is M. Then, the total number of bits transmitted in a frequency hopping frame is PM.

[0062] In the design of a frequency hopping system, the length of the transmission sequence output in step S3 is equal to the total number of bits transmitted in a frequency hopping frame, i.e. (2N+1)×K=PM;

[0063] The transmission sequence output in step S3 is divided into groups of P bits each, namely block 1, block 2... block M.

[0064] In this embodiment, specifically in step S4:

[0065] When the length of the transmission sequence output in step S3 is less than the total number of bits transmitted in a frequency hopping frame, i.e. (2N+1)×K≤PM, Q fixed bits are added after (2N+1)×K bits of the transmission sequence, or the first Q bits of the transmission sequence are added, so that (2N+1)×K+Q=PM. Then, these PM bits of data are divided into groups of P bits each, namely block 1, block 2... block M.

[0066] In this embodiment, specifically, step S4 includes:

[0067] The data bits in the blocks are assigned to the corresponding frequency hopping pulses, i.e., block 1 is assigned to frequency hopping pulse 1, block 2 is assigned to frequency hopping pulse 2, ... block M is assigned to frequency hopping pulse M;

[0068] Each hop bit information is modulated, and the frequency synthesizer is controlled according to the frequency pattern of the frequency hopping pulse. Then, signals such as synchronization segment and frequency switching segment are added to send out the frequency hopping signal.

[0069] Example 2

[0070] Please see Figure 3 Example 2 is an instance of Turbo code interleaving in a frequency hopping system, where the Turbo code transmission method of the frequency hopping system proposed in Example 1 is at a code rate of 1 / 3.

[0071] The information sequence length K = 512, and the Turbo code rate is 1 / 3.

[0072] Information sequence {x k The data is fed into component encoder 1 for encoding, and the output verification sequence is {y}. k}, y k ∈{0,1}, 1≤i≤N, 0≤k≤K-1, {x k It is also output as a system sequence.

[0073] At the same time, {x k The sequence after passing through interleaver A is fed into component encoder 2 for encoding, and the output check sequence is {z}. k}, z k ∈{0,1}, 1≤i≤N, 0≤k≤K-1.

[0074] {x k}, {y k},{z k All sequences are of length K = 512, and there are 3 groups in total.

[0075] The system sequence {x k} and check sequence {y k},{z k There are 3 sets of sequences, each fed into a different interleaver. Each interleaver has a depth of K = 512. k} is fed into interleaver B1, {y k} is fed into interleaver B2, {z k The sequence is fed into interleaver B3, which resets the positions of the elements in the sequence. The resulting interleaved sequence is the system sequence {x′}. k}, verify the sequence {y′ k},{z′ k}

[0076] sequence {x′ k},{y′ k} and {z′ k}, input a matrix of dimension 3×512 in sequence; where {x′ k Input the first row of the matrix, {y′ k Input the second row of the matrix, {z′ k Enter the third row of the matrix.

[0077] When reading the matrix, the matrix elements are read column by column to obtain the transmission sequence x′0,y′0,z′0,x′1,y′1,z′1,x′2,y′2,z′2,…,x′ 511 ,y′ 511 ,z′ 511 The total length of the sequence is 3 × 512 = 1536;

[0078] In the frequency hopping system, each group of frequency hopping frames is designed to have 32 hops, with each hop carrying 48 bits.

[0079] Divide the transmission sequence into blocks of 48 bits each, then x′0, y′0, z′0, x′1, y′1, z′1, ..., x′ 15 ,y′ 15 ,z′ 15 A total of 48 bits constitute block 1, x′ 16 ,y′ 16 ,z′ 16 ,x′ 17 ,y′ 17 ,z′ 17 ,…,x′ 31 ,y′ 31 ,z′ 31 A total of 48 bits are in block 2, ..., x′ 496 ,y′ 496 ,z′ 496 ,x′ 497,y′ 497 ,z′ 497 ,…,x′ 511 ,y′ 511 ,z′ 511 A total of 48 bits constitute block 32;

[0080] The data bits in the blocks are assigned to the corresponding frequency hopping pulses, i.e., block 1 is assigned to frequency hopping pulse 1, block 2 is assigned to frequency hopping pulse 2, ... block 32 is assigned to frequency hopping pulse 32.

[0081] Each hop bit information is BPSK modulated, and the frequency synthesizer is controlled according to the frequency pattern of the frequency hopping pulse. Then, signals such as synchronization segment and frequency switching segment are added to send out the frequency hopping signal.

[0082] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0083] This background section is provided to generally present the context of the invention. The work of the currently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither expressly nor impliedly acknowledged as prior art to the invention.

Claims

1. A method for transmitting Turbo codes in a frequency hopping system, characterized in that, include: Step S1: Process the information sequence Perform Turbo encoding to generate a system sequence. , verification sequence and check sequence ; Step S2: Sequence of the system , verification sequence and check sequence The data are fed into different interleavers to obtain the interleaved system sequence. , verification sequence and check sequence ; Step S3: Sequence of the system , verification sequence and check sequence Perform data multiplexing to obtain the transmission sequence; Step S4: Divide the transmission sequence into blocks, namely block 1, block 2... block N, with the number of bits in each block corresponding to the number of bits transmitted by one frequency modulation pulse; Step S5: Distribute the block data to each frequency hopping pulse, complete the modulation, and send it according to the frequency hopping system frame structure; Step S1 includes: Length is Information sequence Send in Each component encoder encodes the output. Group verification sequence is ; It is also output as a system sequence; at the same time, The sequence after the interleaver is fed into Each component encoder encodes the output. Group verification sequence is ; , , All are of length sequence, total Group; Step S2 includes: System sequence , verification sequence and check sequence ,common Group sequences, respectively sent into Each interleaver has a depth of 1, which resets the positions of elements in the sequence. The interleaved sequence is a systematic sequence. , verification sequence and check sequence ; Step S3 includes: Interleaved system sequence , verification sequence and check sequence Enter the dimensions in sequence. The matrix is ​​used to achieve data multiplexing by writing rows and reading columns.

2. The method for transmitting Turbo codes in a frequency hopping system according to claim 1, characterized in that, Step S4 includes: In a frequency hopping system, each frequency hopping pulse carries the following number of coded bits: The number of frequency hopping pulses in a frequency hopping frame is Then the total number of bits transmitted in a frequency hopping frame is ; In frequency hopping system design, the length of the transmission sequence output in step S3 is equal to the total number of bits transmitted in one frequency hopping frame, i.e. ; The sending sequence output in step S3 is processed according to each... The bits are grouped into blocks, namely block 1, block 2... blocks. .

3. The method for transmitting Turbo codes in a frequency hopping system according to claim 2, characterized in that, In step S4: When the length of the transmission sequence output in step S3 is less than the total number of bits transmitted in a frequency hopping frame, that is... At that time, by sending the sequence After one bit, add Q fixed bits, or add the first Q bits of the transmitted sequence, so that... Then take this Bit data, per The bits are grouped into blocks, namely block 1, block 2... blocks. .

4. The method for transmitting Turbo codes in a frequency hopping system according to claim 3, characterized in that, Step S4 includes: The data bits in the blocks are allocated to the corresponding frequency hopping pulses, i.e., block 1 is allocated to frequency hopping pulse 1, block 2 is allocated to frequency hopping pulse 2, and so on. Distributed to frequency hopping pulse ; Each hop bit information is modulated, and the frequency synthesizer is controlled according to the frequency pattern of the frequency hopping pulse. Then, a synchronization segment and a frequency switching segment signal are added to send out the frequency hopping signal.

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