A frequency modulation differential chaos phase shift keying communication method based on cyclic spectrum analysis and related device

Abstract

The application discloses a frequency modulation differential chaos shift keying communication method based on cyclic spectrum analysis and related devices. The application introduces a double modulation mechanism of cyclic shift index and cosine frequency index in the block level processing in the traditional DCSK framework, performs a cyclic shift operation on a reference segment, and performs a cosine sequence multiplicative weighting on a frequency modulation transmission sequence. A controllable cosine normalization frequency parameter is introduced to introduce a detectable cyclic stationary feature, map additional information bits to the shift index and the frequency index, and significantly improve the spectral efficiency. Meanwhile, the codebook coding of the index bits reduces the misjudgment probability while increasing the effective payload bits, effectively improves the communication reliability, and solves the technical problem that the existing chaos communication scheme cannot simultaneously consider the spectral efficiency and the communication reliability.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a frequency modulation differential chaotic phase shift keying communication method and related apparatus based on cyclic spectrum analysis. Background Technology

[0002] In the field of wireless communication, Differential Chaos Phase Shift Keying (DCSK), as a typical incoherent chaotic modulation method, has attracted attention due to its simple implementation, lack of need for chaotic synchronization at the transmitting and receiving ends, and strong resistance to multipath propagation. To improve the robustness of chaotic communication in noisy and fading channels, Frequency Modulated Differential Chaotic Phase Shift Keying (FM-DCSK) has been proposed. This scheme first modulates the carrier frequency with a chaotic sequence, and then uses DCSK to divide the signal into reference and data segments for transmission and detection. Although this enhances the signal's anti-interference capability, it does not increase the number of information bits carried by each symbol, resulting in limited spectral utilization.

[0003] To improve spectral efficiency, indexed modulation (IM) technology has been introduced into chaotic communication to carry additional bits. A typical indexed modulation technique is code-indexed modulation DCSK (CIM-DCSK), which uses different chaotic code sequences or spreading codes as indices to transmit additional bits. That is, each symbol carries information through the selected codebook index in addition to regular data bits. This indexed modulation method improves data rate and spectral efficiency to some extent, but its index decision reliability and complexity are constrained by codebook size, inter-code correlation, and multipath conditions, thus increasing implementation complexity. Furthermore, another type of indexing scheme based on cyclic shift embeds index information by changing the cyclic shift amount of the reference segment. However, in multipath fading and low signal-to-noise ratio environments, the position of the correlation peak at the receiver is prone to misjudgment. Because the correlation metrics between different shift amounts are small, and the index information relies entirely on a single, fragile peak detection, lacking any redundancy or error correction mechanism, parameter misjudgment can easily lead to a significant deterioration in overall performance.

[0004] Therefore, existing chaotic communication schemes often face a common problem: while pursuing high spectral efficiency, it is difficult to maintain high reliable communication performance in complex real-world channels. Summary of the Invention

[0005] This invention provides a frequency modulation differential chaotic phase shift keying communication method and related apparatus based on cyclic spectrum analysis, which solves the technical problem that existing chaotic communication schemes cannot simultaneously achieve both spectral efficiency and reliability.

[0006] This invention provides a frequency-modulated differential chaotic phase-shift keying communication method based on cyclic spectrum analysis, the method comprising:

[0007] The initial information bit stream is divided into blocks to obtain multiple transmission signal blocks; the information bit stream in each transmission signal block is divided into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase shift keying symbols with a preset number of symbols;

[0008] Based on the baseband discrete chaotic sequence generated by the chaotic signal generator, the data bits, and the preset spreading factor, an initial transmission sequence of multiple differential chaotic phase shift keying symbols is generated.

[0009] The index bits of each transmitted signal block are encoded using a codebook to obtain a codebook sequence; the first parameter codeword sequence and the second parameter codeword sequence are extracted from the codebook index sequence.

[0010] Based on the Gray encoding mapping rule, the first parameter codeword sequence is mapped to a cosine sequence parameter, and the second parameter codeword sequence is mapped to a cyclic shift parameter; based on the preset spreading factor, the cosine sequence parameter is converted into the corresponding frequency parameter.

[0011] A corresponding cosine-weighted sequence is generated based on the frequency parameters, and the cosine-weighted sequence is multiplied by the corresponding initial transmission sequence to obtain a frequency-modulated transmission sequence; a cyclic shift embedding is performed on the reference segment sequence in the associated frequency-modulated transmission sequence based on the cyclic shift parameters to obtain a cyclic transmission sequence;

[0012] The target transmission sequence is obtained by concatenating the cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmission signal block.

[0013] Optionally, the method further includes:

[0014] The discrete signals of the target transmission sequence transmitted through the transmission channel are received and symbol synchronization and block processing are performed to obtain multiple received signal blocks;

[0015] Based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, cyclic shift detection is performed on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block, and the relevant energy metric of each candidate cyclic shift parameter is calculated, thereby establishing the first soft information set;

[0016] Multiple candidate frequency parameters are determined based on the candidate cosine sequence parameters in the preset cosine sequence parameter candidate set. Cyclic spectrum analysis is performed on the received signal block based on each candidate frequency parameter to calculate the block-level cyclic spectrum metric corresponding to each candidate cosine sequence parameter, thereby establishing a second soft information set.

[0017] Based on the first soft information set and the second soft information set, a joint decision is made to determine the target cosine sequence parameter and the target shift parameter;

[0018] The target shift parameter is used to perform reverse cyclic shift compensation on the reference segment sequence in the differential chaotic phase shift keying symbol of the associated received signal block to update the received signal block, and the corresponding data bits are recovered by correlation demodulation of the updated received signal block.

[0019] Based on the Gray encoding mapping rules, the index bits are recovered by inverse mapping according to the target cosine sequence parameters and the target shift parameters; the information bits of each received signal block are recovered based on the recovered index bits and the corresponding data bits.

[0020] Optionally, the number of index bits is four; the step of encoding the index bits of each transmitted signal block into a codebook to obtain a codebook sequence; and extracting the first parameter codeword sequence and the second parameter codeword sequence from the codebook index sequence includes:

[0021] Perform an XOR operation on the index bits of each transmitted signal block to obtain the corresponding redundancy check bits; the codebook sequence is composed of the four index bits and the redundancy check bits in codeword order;

[0022] The first three bits of the codebook sequence are used as the first parameter codeword sequence, and the last two bits of the codebook sequence are used as the second parameter codeword sequence.

[0023] Optionally, the cosine-weighted sequence is represented as:

[0024]

[0025] In the formula: The cosine weighted value of the cosine weighted sequence of the k-th differential chaotic phase shift keying symbol at the n-th sampling point; Let be the phase value of the k-th differential chaotic phase shift keying symbol; For normalized frequency parameters, , For the parameters of the cosine sequence, It is the spreading factor;

[0026] The frequency-modulated transmission sequence is represented as follows:

[0027]

[0028] In the formula: The discrete signal of the frequency-modulated transmission sequence of the k-th differential chaotic phase-shift keying symbol at the nth sampling point; The discrete signal of the initial transmission sequence of the k-th differential chaotic phase shift keying symbol at the n-th sampling point;

[0029] The reference segment sequence in the cyclic emission sequence is represented as follows:

[0030]

[0031] In the formula: The discrete signal of the cyclic emission sequence of the kth differential chaotic phase shift keying symbol at the nth sampling point; This is the cyclic shift parameter.

[0032] Optionally, the step of generating an initial transmission sequence of multiple differential chaotic phase shift keying symbols based on the baseband discrete chaotic sequence generated by the chaotic signal generator, the data bits, and the preset spreading factor includes:

[0033] Based on the baseband discrete chaotic sequence generated by the chaotic signal generator and the preset spreading factor, a reference segment sequence for each differential chaotic phase shift keying symbol is generated.

[0034] The data bits of each differential chaotic phase shift keying symbol are mapped to modulation coefficients, and the reference segment sequence is multiplied with the corresponding modulation coefficients to obtain the data segment sequence of each differential chaotic phase shift keying symbol.

[0035] The reference segment sequence and the corresponding data segment sequence are concatenated sequentially in the time domain to generate an initial transmission sequence of multiple differential chaotic phase shift keying symbols.

[0036] Optionally, the step of performing cyclic shift detection on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, and calculating the relevant energy metric for each candidate cyclic shift parameter to establish the first soft information set includes:

[0037] Based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block is subjected to reverse cyclic compensation to obtain the real reference segment sequence.

[0038] Based on the real reference segment sequence and its corresponding data segment sequence, calculate the cross-correlation value of each candidate cyclic shift parameter; based on the cross-correlation value, calculate the energy metric of each candidate cyclic shift parameter;

[0039] The energy measures of all differential chaotic phase shift keying symbols in each received signal block under the corresponding candidate cyclic shift parameters are accumulated to obtain the relevant energy measures of each received signal block under each candidate cyclic shift parameter.

[0040] Based on the relevant energy metric of each received signal block under each candidate cyclic shift parameter, a first soft information set for each received signal block is established.

[0041] Optionally, the step of determining multiple candidate frequency parameters based on candidate cosine sequence parameters in a preset candidate set of cosine sequence parameters, performing cyclic spectrum analysis on the received signal block based on each candidate frequency parameter, and calculating the block-level cyclic spectrum metric corresponding to each candidate cosine sequence parameter to establish a second soft information set includes:

[0042] Calculate the corresponding candidate frequency parameter based on each candidate cosine sequence parameter in the preset candidate set of cosine sequence parameters;

[0043] The received signal block is segmented and windowed to obtain multiple received signal segments;

[0044] Based on each candidate frequency parameter, the received signal segment is subjected to positive and negative half-cycle frequency shift to obtain two corresponding frequency shift components; the two corresponding frequency shift components are subjected to Fourier transform and cyclic spectrum correlation function estimation to obtain the cyclic spectrum correlation estimate of the corresponding received signal segment;

[0045] Energy aggregation calculation is performed on the cyclic spectrum correlation estimate within the preset frequency domain to obtain the segment-level metric of the corresponding received signal segment;

[0046] The mean of the segment-level metric for all received signal segments of each received signal block is calculated to obtain the block-level cyclic spectrum metric for each received signal block under each candidate cosine sequence parameter.

[0047] Based on the block-level cyclic spectrum metric of each received signal block under each candidate cosine sequence parameter, a second soft information set for each received signal block is established.

[0048] This invention also provides a frequency-modulated differential chaotic phase-shift keying communication device based on cyclic spectrum analysis, the device comprising:

[0049] The transmission block module is used to divide the initial information bit stream into blocks to obtain multiple transmission signal blocks; the information bit stream in each transmission signal block is divided into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase shift keying symbols with a preset number of symbols;

[0050] The modulation module is used to generate an initial transmission sequence of multiple differential chaotic phase shift keying symbols based on the baseband discrete chaotic sequence generated by the chaotic signal generator, the data bits, and the preset spreading factor;

[0051] The codebook encoding module is used to encode the index bits of each transmitted signal block to obtain a codebook sequence; and to extract the first parameter codeword sequence and the second parameter codeword sequence from the codebook index sequence.

[0052] The mapping module is used to map the first parameter codeword sequence into a cosine sequence parameter and the second parameter codeword sequence into a cyclic shift parameter based on the Gray encoding mapping rule; and to convert the cosine sequence parameter into a corresponding frequency parameter based on the preset spreading factor.

[0053] The index embedding module is used to generate a corresponding cosine-weighted sequence based on the frequency parameters, and perform a dot product operation between the cosine-weighted sequence and the corresponding initial transmission sequence to obtain a frequency-modulated transmission sequence; and to perform cyclic shift embedding on the reference segment sequence in the associated frequency-modulated transmission sequence based on the cyclic shift parameters to obtain a cyclic transmission sequence.

[0054] The target transmission sequence generation module is used to concatenate and splice the cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmission signal block to obtain the target transmission sequence.

[0055] This invention also provides a computer-readable storage medium storing a computer program or instructions thereon, which, when executed by a processor, implements the steps of the frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis as described above.

[0056] This invention also provides a computer program product, including a computer program or instructions, characterized in that, when the computer program or instructions are executed by a processor, they implement the steps of the frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis as described above.

[0057] As can be seen from the above technical solutions, the present invention has the following advantages:

[0058] This invention provides a frequency-modulated differential chaotic phase-shift keying (PSK) communication method and related apparatus based on cyclic spectrum analysis. The method includes: dividing an initial information bit stream into blocks to obtain multiple transmission signal blocks; dividing the information bit stream in each transmission signal block into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase-shift keying symbols of a preset number of symbols; generating an initial transmission sequence of multiple differential chaotic phase-shift keying symbols based on a baseband discrete chaotic sequence generated by a chaotic signal generator, the data bits, and a preset spreading factor; encoding the index bits of each transmission signal block using a codebook to obtain a codebook sequence; and extracting a first parameter from the codebook index sequence. The codeword sequence and the second parameter codeword sequence are generated. Based on the Gray coding mapping rule, the first parameter codeword sequence is mapped to a cosine sequence parameter, and the second parameter codeword sequence is mapped to a cyclic shift parameter. Based on the preset spreading factor, the cosine sequence parameter is converted into the corresponding frequency parameter. The corresponding cosine weighted sequence is generated according to the frequency parameter, and the cosine weighted sequence is multiplied by the corresponding initial transmission sequence to obtain the frequency modulation transmission sequence. Based on the cyclic shift parameter, the reference segment sequence in the associated frequency modulation transmission sequence is cyclically shifted and embedded to obtain the cyclic transmission sequence. The cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmitted signal block are concatenated and spliced ​​to obtain the target transmission sequence.

[0059] This invention introduces a dual modulation mechanism of cyclic shift index and cosine frequency index into the traditional DCSK framework, which involves block-level processing. By performing cyclic shift operations on the reference segment and cosine multiplicative weighting on the frequency-modulated transmission sequence, detectable cyclic stationary features are introduced through controllable cosine normalized frequency parameters. Additional information bits are mapped to the shift index and frequency index, significantly improving spectral efficiency. At the same time, the codebook encoding of the index bits increases the effective payload bits while reducing the probability of misjudgment, effectively improving communication reliability. This solves the technical problem that existing chaotic communication schemes cannot simultaneously achieve both spectral efficiency and general reliability. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 A flowchart illustrating the steps of a frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis, provided in this embodiment of the invention;

[0062] Figure 2 This is a transmitter block diagram of a shift-indexed FM-DCSK system combined with cyclic spectrum analysis provided in an embodiment of the present invention;

[0063] Figure 3 A flowchart illustrating the design process of codebook encoding provided in this embodiment of the invention;

[0064] Figure 4 This is a receiver block diagram of a shift-indexed FM-DCSK system combined with cyclic spectrum analysis provided in an embodiment of the present invention;

[0065] Figure 5 A comparative performance diagram of shift index FM-DCSK, traditional code index DCSK (CIM-DCSK), and multicarrier DCSK (MC-DCSK) provided for embodiments of the present invention under cyclic spectrum analysis assisted in multipath and Gaussian channels;

[0066] Figure 6 A flowchart of the transmitter and receiver processing of a DCSK system that can be implemented using existing technology, provided for embodiments of the present invention;

[0067] Figure 7 This is a structural block diagram of a frequency modulation differential chaotic phase shift keying communication device based on cyclic spectrum analysis, provided as an embodiment of the present invention. Detailed Implementation

[0068] This invention provides a frequency modulation differential chaotic phase shift keying communication method and related apparatus based on cyclic spectrum analysis, which solves the technical problem that existing chaotic communication schemes cannot simultaneously achieve both spectral efficiency and reliability.

[0069] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] It should be noted that, in the optional embodiments of the present invention, the data related to object information, etc., requires the permission or consent of the object when the embodiments of the present invention are applied to specific products or technologies. Furthermore, the collection, use, and processing of the relevant data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. In other words, if the embodiments of the present invention involve data related to an object, it needs to be obtained with the object's authorization and consent, the authorization and consent of relevant departments, and in accordance with the relevant laws, regulations, and standards of the country and region. If the embodiments involve personal information, the acquisition of all personal information requires the individual's consent. If sensitive information is involved, the separate consent of the information subject is required. The embodiments also need to be implemented with the object's authorization and consent.

[0071] Please see Figure 6 The following section further explains the general performance of DCSK systems achievable with existing technologies by describing the transmitter and receiver processing flow of the DCSK system.

[0072] DCSK is a typical incoherent chaotic modulation method: the transmitter transmits two signals of equal duration in each symbol: the first is a reference chaotic sequence, and the second is a chaotic sequence carrying the information, usually implemented by multiplying the reference sequence by the information bits. The receiver uses a correlator to correlate the reference sequence with the information sequence, determining whether they are in phase or out of phase to recover the bits. DCSK does not require a chaotic generator for synchronous transmission and reception, and has the advantages of simple implementation and strong resistance to multipath propagation.

[0073] For details, please refer to Figure 6 At the transmitting end, a chaotic signal generator generates a signal of length [length missing]. Discrete chaotic reference sequence Each symbol period consists of two equal-length intervals, therefore the spreading factor can be written as: For the first one information bit Define the polarity coefficient The emission sequence of this symbol can be represented in classical form as follows: , among which the former Each sampling point sends a reference segment. ,back Each sampling point sends an information segment .

[0074] The receiver uses a time-delay correlation structure to perform incoherent detection, multiplying the reference segment and the data segment point by point and accumulating the results to obtain the decision statistic:

[0075]

[0076] In the formula: Let i be the decision statistic for the i-th symbol. The reference segment sequence of the i-th symbol is the signal at the n-th sampling point. The data segment sequence of the i-th symbol is the signal at the n-th sampling point.

[0077] Because the data segment is at the sending end In the ideal form The symbol is composed of Therefore, the decision can be made using a threshold of 0:

[0078]

[0079] This process does not rely on carrier phase estimation and channel estimation, thus reflecting the noncoherent reception characteristics of the traditional DCSK scheme.

[0080] To improve the robustness of traditional DCSK schemes in chaotic communication under noisy and fading channels, existing technologies have successively proposed frequency modulation DCSK (FM-DCSK), code indexed modulation DCSK (CIM-DCSK), and indexed modulation schemes based on cyclic shift. Among them, FM-DCSK mainly enhances anti-interference capability but does not increase the number of information bits carried per symbol; CIM-DCSK carries additional bits through codebook indexing, which improves spectral efficiency to some extent, but its index decision reliability is severely limited by codebook size, inter-symbol correlation, and multipath conditions; although the indexed modulation scheme based on cyclic shift can carry additional information with shift amount, in multipath fading and low signal-to-noise ratio environments, the correlation peak positions of the reference segment and data segment are easily misjudged, and it relies entirely on single peak detection, lacks redundancy constraints and error correction mechanisms, and parameter detection errors will directly propagate to the entire data block, causing a significant bit error rate.

[0081] To address the common problem of existing DCSK chaotic communication failing to simultaneously achieve both spectral efficiency and reliability, this invention provides a frequency-modulated differential chaotic phase-shift keying communication method based on cyclic spectrum analysis. It establishes an encoding mechanism for the reference segment cyclic shift index and the cosine modulation frequency index, mapping additional information bits to the shift and frequency indices, enabling each chaotic symbol to transmit more information bits. Simultaneously, it introduces a codebook design with Gray coding mapping and redundancy check bits to encode the index bits, increasing the effective payload bits while reducing the probability of misjudgment and effectively improving communication reliability.

[0082] Please see Figure 1 This invention provides a frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis, applied to a shift index FM-DCSK system combined with cyclic spectrum analysis. The method includes:

[0083] Step 101: Divide the initial information bit stream into blocks to obtain multiple transmission signal blocks; divide the information bit stream in each transmission signal block into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase shift keying symbols with a preset number of symbols.

[0084] The shift-indexed FM-DCSK system incorporating cyclic spectrum analysis includes a transmitter and a receiver; please refer to [link / reference needed]. Figure 2 This embodiment relates to a transmitter. After the initial information bit stream is input to the transmitter, the initial information bit stream is divided into blocks to obtain multiple transmission signal blocks. Each transmission signal block includes B consecutive differential chaotic phase shift keying symbols. The information bit stream in each transmission signal block is divided into corresponding data bits and index bits. That is, B information bits are used as data bits, and each differential chaotic phase shift keying symbol corresponds to one of the data bits for DCSK modulation. Four bits are allocated from the transmission signal block as index bits, which serve as the index parameters for the entire transmission signal block.

[0085] Assuming the spreading factor is L, then the sampling length of each differential chaotic phase shift keying symbol is It consists of a reference segment and a data segment, both of which have a length of L. Furthermore, in practical applications, considering factors such as the general performance and implementation complexity of the DCSK system, the preferred number of differential chaotic phase shift keying symbols B for each transmitted signal block is 2, and the preferred number of spreading factors L is 256.

[0086] Step 102: Based on the baseband discrete chaotic sequence, data bits and preset spreading factor generated by the chaotic signal generator, generate the initial transmission sequence of multiple differential chaotic phase shift keying symbols.

[0087] In this embodiment, for each differential chaotic phase shift keying symbol, a reference segment sequence with a preset spreading factor L is extracted from the baseband discrete chaotic sequence generated by the chaotic signal generator; based on the data bits allocated to the symbol and the corresponding reference segment, the data segment sequence of the symbol is generated, thereby forming the initial transmission sequence of the symbol; the steps realize the traditional DCSK modulation process, construct a "reference-data" framing structure for each symbol, so that the receiver can recover the data bits using incoherent correlation demodulation.

[0088] In one specific implementation, step 102 may include the following steps:

[0089] S11. Based on the baseband discrete chaotic sequence generated by the chaotic signal generator and the preset spreading factor, a reference segment sequence for each differential chaotic phase shift keying symbol is generated.

[0090] S12. Map the data bits of each differential chaotic phase shift keying symbol to modulation coefficients, and multiply the reference segment sequence with the corresponding modulation coefficients to obtain the data segment sequence of each differential chaotic phase shift keying symbol.

[0091] S13. The reference segment sequence and the corresponding data segment sequence are sequentially concatenated in the time domain to generate the initial emission sequence of multiple differential chaotic phase shift keying symbols.

[0092] In this specific embodiment, please refer to Figure 2 First, a chaotic signal generator produces a baseband discrete chaotic sequence. This sequence is then input to a frequency modulation (FM) module for frequency modulation processing, converting it into a frequency-modulated chaotic carrier. The FM module transforms the chaotic sequence into a signal that controls frequency changes, essentially using a baseband signal to control the carrier's "instantaneous frequency," causing the carrier frequency to continuously shift with the baseband signal, thus recording baseband information onto the carrier frequency changes. Subsequently, based on a preset spreading factor, the frequency-modulated chaotic carrier is sliced ​​according to differential chaotic phase-shift keying symbols to obtain the corresponding reference segment sequence. The reference segment sequence of a differential chaotic phase-shift keying symbol can be represented as: .

[0093] Next, the data bits of each differential chaotic phase shift keying symbol are mapped to modulation coefficients. The reference segment sequence is multiplied by the corresponding modulation coefficients using a modulator to obtain the data segment sequence of each differential chaotic phase shift keying symbol. ,Right now .

[0094] Finally, the reference segment sequence and the corresponding data segment sequence are concatenated sequentially in the time domain to generate the initial emission sequences of multiple differential chaotic phase shift keying symbols. Among them, the first... The discrete signal of the initial emission sequence of differential chaotic phase shift keying symbols at the nth sampling point Represented as:

[0095] .

[0096] Step 103: Codebook encoding is performed on the index bits of each transmitted signal block to obtain a codebook sequence; the first parameter codeword sequence and the second parameter codeword sequence are extracted from the codebook index sequence.

[0097] It is understandable that the number of index bits allocated to each transmitted signal block is 4; this step encodes the index bits allocated to each transmitted signal block into a codebook, introducing controllable redundancy into the index bits, and generating a codebook sequence containing information bits and parity bits; according to the preset mapping rules, the first parameter codeword sequence and the second parameter codeword sequence are split from the codebook sequence, which correspond to the encoding input of the subsequent cosine frequency index and cyclic shift index, respectively.

[0098] In one specific implementation, step 103 may include the following steps:

[0099] S21. Perform an XOR operation on the index bits of each transmitted signal block to obtain the corresponding redundancy check bits; the four index bits and the redundancy check bits are arranged in codeword order to form a codebook sequence;

[0100] S22. Use the first three bits of the codebook sequence as the first parameter codeword sequence, and the last two bits of the codebook sequence as the second parameter codeword sequence.

[0101] In this specific embodiment, such as Figure 3 As shown, the four index bits Encoding yields the fifth parameter codeword The fifth parameter codeword As a redundancy check bit, that is:

[0102]

[0103] The codebook sequence is composed of four index bits and a redundancy check bit in codeword order. The first three bits of the codebook sequence are used to form the codebook sequence. The first parameter is the codeword sequence, with the last two bits in the codebook sequence as the basis. As the second parameter codeword sequence; wherein, the first parameter codeword sequence is used, and the second parameter codeword sequence is used.

[0104] Step 104: Based on the Gray coding mapping rules, map the first parameter codeword sequence to a cosine sequence parameter, and map the second parameter codeword sequence to a cyclic shift parameter; convert the cosine sequence parameter into the corresponding frequency parameter based on the preset spreading factor.

[0105] In this embodiment, based on the Gray encoding mapping rule, the first parameter codeword sequence is mapped to a cosine sequence parameter according to the cosine sequence parameter candidate set, and the second parameter codeword sequence is mapped to a cyclic shift parameter according to the cyclic shift candidate set.

[0106] Specifically, based on the Gray encoding mapping rules, the first parameter codeword sequence is first... Mapped to a candidate set of cosine sequence parameters One cosine sequence parameter ,in This represents the period / cycle index of the cosine sequence parameters within a single differential chaotic phase shift keying symbol over a sampling interval of length 2L; then the cosine sequence parameters... Convert to normalized frequency parameters , .

[0107] Understandably, the candidate set of cosine sequence parameters The cosine sequence in the diagram is formed at the transmitting end by superimposing a continuous cosine sequence of phases onto each differential chaotic phase shift keying symbol within a sampling interval of length 2L. Therefore, the cosine sequence parameters... This controls the number of periods in the cosine sequence within the sign interval. The larger the number of cycles, the more cycles. The smaller the value, the fewer the number of periods. Specifically, when constructing the candidate set of cosine sequence parameters, to ensure that each parameter m in the candidate set is distinguishable, it is only necessary to satisfy... Under the constraint, several even integer intervals can be selected. Even numbers are chosen to ensure stable peaks at the corresponding cyclic frequencies during cyclic spectrum analysis. For example, please refer to Table 1, which shows the mapping relationship between Gray encoding and cosine sequence parameters.

[0108] Table 1 Gray mapping and cosine sequence parameters

[0109]

[0110] Based on the Gray encoding mapping rule, the second parameter codeword sequence Mapped to a cyclic shift candidate set One of the circular shift parameters In constructing the candidate set of cosine sequence parameters, since the cyclic shift parameter is calculated only for the reference segment length L in subsequent calculations, the parameter constraints must be met. Simply set a set of distinguishable shift values. For an example, please refer to Table 2, which shows the... The mapping relationship between Gray encoding and cyclic shift parameters.

[0111] Table 2 Mapping relationship between Gray code and cyclic shift parameters ( )

[0112]

[0113] Step 105: Generate the corresponding cosine-weighted sequence based on the frequency parameters, and perform a dot product operation between the cosine-weighted sequence and the corresponding initial transmission sequence to obtain the frequency modulation transmission sequence; perform cyclic shift embedding on the reference segment sequence in the associated frequency modulation transmission sequence based on the cyclic shift parameters to obtain the cyclic transmission sequence.

[0114] In this embodiment, based on frequency parameters Generate a phase-continuous cosine-weighted sequence ,Right now:

[0115]

[0116] In the formula: The cosine weighted value of the cosine weighted sequence of the k-th differential chaotic phase shift keying symbol at the n-th sampling point; Let be the phase value of the k-th differential chaotic phase shift keying symbol.

[0117] because So when n changes from 0 to At this time, the phase Approximately Therefore, the cosine sequence is approximately complete within this symbol. The first cycle. For the first cycle within the block. and Each symbol, using phase recursion Ensuring the cosine sequence is continuous across symbols within a block ensures that the cosine square product term does not affect the correlation calculation of DCSK symbols at the receiver.

[0118] The cosine-weighted sequence is then multiplied point-by-point with the initial transmission sequence of the symbols within the block to obtain the cosine-weighted transmission sequence, i.e., the frequency-modulated transmission sequence:

[0119]

[0120] In the formula: It is the discrete signal of the frequency-modulated transmission sequence of the k-th differential chaotic phase shift keying symbol at the nth sampling point.

[0121] Next, based on the cyclic shift parameters A cyclic shift embedding is performed on the reference segment sequence in the associated frequency-modulated transmission sequence to obtain a cyclic transmission sequence; wherein, the reference segment sequence in the cyclic transmission sequence Represented as:

[0122]

[0123] It is understood that this step only performs cyclic shift embedding on the reference segment sequence in the frequency modulated transmission sequence, while the data segment sequence in the frequency modulated transmission sequence remains unchanged.

[0124] Step 106: Concatenate and splice the cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmission signal block to obtain the target transmission sequence.

[0125] In this embodiment, the differential chaotic phase shift keying symbols in the transmitted signal block are concatenated and spliced ​​to form the target transmission sequence and sent to the transmission channel, thus realizing the complete transmission processing link of "chaotic reference construction - differential framing - cosine weighted embedding - reference segment cyclic shift embedding - concatenated transmission".

[0126] This invention employs a coding mechanism combining a reference segment cyclic shift index and a cosine modulation frequency index to form a composite index modulation scheme. By performing a cyclic shift operation on the DCSK reference segment and applying cosine sequence multiplicative weighting to the baseband signal, detectable cyclic stationary characteristics are introduced through a controllable cosine normalized frequency parameter, mapping additional information bits onto the shift index and frequency index. Simultaneously, Gray coding mapping and redundancy check bits are introduced to encode the index bits, increasing the effective load bits while reducing the probability of misjudgment, thereby improving spectral efficiency and ensuring demodulation reliability.

[0127] Another embodiment of the present invention provides a frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis, which further includes:

[0128] Step 201: Receive the discrete signals of the target transmission sequence through the transmission channel and perform symbol synchronization and block processing to obtain multiple received signal blocks.

[0129] It should be noted that the baseband discrete signal of the target transmission sequence output by the transmitter is processed by a multipath channel and noise to form the received signal; please refer to [link to relevant documentation]. Figure 5 This embodiment relates to a receiver that receives signals and performs symbol synchronization and block processing at the receiving end to obtain multiple received signal blocks. Each received signal block corresponds to B differential chaotic phase shift keying symbols, the first of which... The length of the intra-block receive sequence corresponding to the block receive signal is , recorded as ,in For the first The block receives the discrete signal at the nth sampling point of the signal block. To receive signals, differential chaotic phase shift keying symbols within each block share the same set of parameter decision results to improve detection robustness.

[0130] Step 202: Based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, perform cyclic shift detection on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block, calculate the relevant energy metric of each candidate cyclic shift parameter, and thus establish the first soft information set.

[0131] It should be noted that, for each candidate shift amount in the cyclic shift candidate set, cyclic shift detection is performed on the reference segment sequence of each symbol in the current received signal block to obtain the relevant energy metric corresponding to the candidate shift amount. The relevant energy metric of each candidate shift amount is output to form the first soft information set. This step generates a coarse judgment result of cyclic shift, retains the credibility difference of each candidate shift amount, and provides a fusionable metric basis for subsequent joint judgment with cyclic spectrum soft information.

[0132] In one specific implementation, step 202 includes the following steps:

[0133] S31. Based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, perform cyclic shift detection on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block to obtain the real reference segment sequence.

[0134] S32. Based on the real reference segment sequence and its corresponding data segment sequence, calculate the cross-correlation value of each candidate cyclic shift parameter; based on the cross-correlation value, calculate the energy metric of each candidate cyclic shift parameter.

[0135] S33. Accumulate the energy metrics of all differential chaotic phase shift keying symbols in each received signal block under the corresponding candidate cyclic shift parameters to obtain the relevant energy metrics of each received signal block under each candidate cyclic shift parameter.

[0136] S34. Based on the relevant energy metric of each received signal block under each candidate cyclic shift parameter, establish the first soft information set of each received signal block.

[0137] In this specific embodiment, the receiver performs cyclic shift detection on the reference segment sequence: firstly, based on a preset cyclic shift candidate set... Any candidate cyclic shift parameter in Reverse cyclic compensation is performed on the reference segment sequence of each symbol within the received signal block to obtain candidate cyclic shift parameters. The corresponding real reference segment sequence, i.e.:

[0138]

[0139] In the formula: Candidate cyclic shift parameters The corresponding real reference segment sequence, Candidate cyclic shift parameters The corresponding reference segment sequence after cyclic shifting at the nth sampling point.

[0140] Next, based on the cyclically shifted reference segment sequence and its corresponding data segment sequence, the cross-correlation value of each candidate cyclic shift parameter is calculated, i.e.:

[0141]

[0142] In the formula: Candidate cyclic shift parameters The cross-correlation value, Candidate cyclic shift parameters The corresponding complex conjugate of the reference segment sequence after cyclic shift at the nth sampling point, A sequence of data segments;

[0143] Based on the cross-correlation value, the energy metric for each candidate cyclic shift parameter is calculated, i.e.:

[0144]

[0145] In the formula: Candidate cyclic shift parameters Energy measurement.

[0146] Then, the energy metrics of all differential chaotic phase shift keying symbols in the received signal block under the corresponding candidate cyclic shift parameters are accumulated to obtain the relevant energy metrics of the received signal block under each candidate cyclic shift parameter, as shown below:

[0147]

[0148] In the formula: For the received signal block, the relevant energy metric is defined for each candidate cyclic shift parameter. For the k-th differential chaotic phase shift keying symbol in the candidate cyclic shift parameter The energy metric; the maximum energy metric is used as the initial shift criterion for the received signal block. .

[0149] Preserve the relevant energy metric of the received signal block under each candidate cyclic shift parameter. As the first set of soft information; among which... For the k-th differential chaotic phase shift keying symbol in the candidate cyclic shift parameter The relevant energy measurement below.

[0150] Step 203: Based on the candidate cosine sequence parameters in the preset candidate cosine sequence parameter set, determine multiple candidate frequency parameters, perform cyclic spectrum analysis on the received signal block based on each candidate frequency parameter, calculate the block-level cyclic spectrum metric corresponding to each candidate cosine sequence parameter, and thus establish the second soft information set.

[0151] In this embodiment, for each candidate cosine sequence parameter, a cyclic spectrum analysis is performed on the received signal block to generate a block-level cyclic spectrum metric for that candidate cosine sequence parameter, and a soft information metric set for each candidate cosine sequence parameter is output. This significantly suppresses the influence of noise and multipath interference on the cyclic spectrum estimation, and provides a highly reliable basis for the credibility of frequency parameters for subsequent joint decision-making.

[0152] In one specific implementation, step 203 includes the following steps:

[0153] S41. Calculate the corresponding candidate frequency parameter based on each candidate cosine sequence parameter in the preset candidate set of cosine sequence parameters;

[0154] S42. The received signal block is segmented and windowed to obtain multiple received signal segments;

[0155] S43. Based on each candidate frequency parameter, perform positive and negative half-cycle frequency shifts on the received signal segment to obtain two corresponding frequency shift components; perform Fourier transform and cyclic spectrum correlation function estimation on the two corresponding frequency shift components to obtain the cyclic spectrum correlation estimate of the corresponding received signal segment.

[0156] S44. Perform energy aggregation calculation on the cyclic spectrum correlation estimate in the preset frequency domain to obtain the segment-level metric of the corresponding received signal segment;

[0157] S45. Calculate the mean of the segment-level metric for all received signal segments of each received signal block to obtain the block-level cyclic spectrum metric for each received signal block under each candidate cosine sequence parameter.

[0158] S46. Based on the block-level cyclic spectrum metric of each received signal block under each candidate cosine sequence parameter, establish the second soft information set of each received signal block.

[0159] It is understandable that the transmitter multiplies the initial transmission sequence by a phase-continuous cosine-weighted sequence, so that the received signal produces stable spectral correlation characteristics at a specific cyclic frequency. Therefore, it is necessary to calculate the spectral correlation intensity to detect the spectral correlation peak of the cosine sequence and perform cyclic spectrum analysis on the received signal block.

[0160] In this specific embodiment, firstly, based on a preset cyclic shift candidate set... For any candidate cyclic shift parameter m, calculate the corresponding normalized candidate frequency parameter. When the phase growth rate within a differential chaotic phase shift keying symbol is taken hour, The phase accumulation within each sampling point is Each cycle, thus at the cycle frequency Detectable spectral correlation peaks are formed nearby;

[0161] To improve the robustness of cyclic spectrum estimation under low signal-to-noise ratio and multipath conditions, the receiver further divides the received signal block into several overlapping segments and performs windowing processing to obtain multiple received signal segments; let the length of each received signal segment be... The discrete index within the segment is The window function is Then the first Segment signal is ,in The step length is the segment size.

[0162] Based on each candidate frequency parameter The receiver constructs two "positive and negative half-cycle frequency shift" sequences within each received signal segment: for each candidate frequency parameter The receiving end assigns positive and negative values ​​to the received signal segments. Frequency shift processing yields two frequency shift components at the nth sampling point. and ,Right now and Performing Fast Fourier Transform on the two frequency shift components respectively yields two transformed frequency shift components. and And calculate the candidate frequency parameters of this segment based on the two transformed frequency shift components. Cyclic spectral correlation estimator at .

[0163] The physical meaning of the cyclic spectrum correlation estimator is as follows: when the signal does indeed contain cyclic frequency components introduced by cosine weighting, the two spectra after positive and negative frequency shifts will exhibit consistency in the corresponding frequency bands, thus... Significant energy accumulation occurs in the neighborhood of a specific frequency domain.

[0164] The receiver further targets the neighborhood of the preset frequency domain. Top Energy aggregation is performed to obtain the segment-level metric for this received signal segment:

[0165]

[0166] In the formula: The segment-level metric for the received signal segment under the candidate cosine sequence parameter m at time t;

[0167] The average segment-level metric of all received signal segments in the received signal block is calculated to obtain the block-level cyclic spectrum metric of the received signal block under each candidate frequency parameter, as shown below:

[0168]

[0169] In the formula: This is the block-level cyclic spectrum metric for the b-th signal block under the candidate cosine sequence parameter m.

[0170] Finally, the receiver uses the maximum metric criterion to obtain the preliminary judgment result of the cosine sequence parameters of the received signal block. And at the same time retain the vector As a second set of soft information, it is used for joint decision-making and consistency constraint error correction with the shift detection soft metric, thereby reducing the impact of misjudgment in a single step on the overall performance.

[0171] Step 204: Make a joint decision based on the first soft information set and the second soft information set to determine the target cosine sequence parameters and the target shift parameters.

[0172] Understandably, this step primarily involves performing joint decision-making based on codebook constraints: the sending end adopts... The "4→5" redundancy structure allows the receiver to utilize the first soft information set (shift detection soft measure). With the second soft information set (cycle spectrum detection softness measure) Joint decisions are made only within the set of legal combinations, and the combination with the highest score is selected as the parameter decision after error correction, that is, the target cosine sequence parameter and the target shift parameter are determined. The set of valid combinations refers to the set of all (m, d) parameter pairs allowed by the redundancy coding rules at the transmitter.

[0173] Through this joint decision mechanism, even if the initial decision of a single path is incorrect, as long as the soft metric can still reflect the credibility difference between candidate combinations, the receiver can still use consistency constraints to bring the decision back to a credible and valid combination, thereby significantly reducing the impact of parameter misjudgment on the overall bit error rate performance.

[0174] Step 205: Use the target shift parameter to perform reverse cyclic shift compensation on the reference segment sequence in the differential chaotic phase shift keying symbol of the associated received signal block to update the received signal block, and recover the corresponding data bits by correlation demodulation of the updated received signal block.

[0175] In this step, the reference segment shift compensation module uses the target shift amount parameter to perform reverse cyclic shift compensation on the reference segment sequence in the differential chaotic phase shift keying symbol of the associated received signal block in order to update the information sequence in the received signal block.

[0176] Specifically, using the target shift parameter As the shift decision after error correction, reverse cyclic shift compensation is performed on the reference segment sequence of each differential chaotic phase shift keying symbol in the b-th received signal block to obtain the compensated reference segment sequence. The data segment sequence of the received signal block is then maintained as This updates the received signal block; subsequently, the data bits are recovered using the reference segment and data segment correlation decision of the updated received signal block, and then... Mapped to Output.

[0177] Step 206: Based on the Gray encoding mapping rule, perform inverse mapping to recover the index bits according to the target cosine sequence parameters and the target shift parameters; recover the information bits of each received signal block based on the recovered index bits and the corresponding data bits.

[0178] In this embodiment, based on the Gray encoding mapping rule, according to the target cosine sequence parameters... and target shift parameters The receiver obtains 4 valid index bits for the received signal block by remapping according to the parameter numbering mapping rule consistent with that of the transmitter. Subsequently, the recovered 4 index bits are concatenated with the data bits obtained by demodulation in step 205 within the same received information block to form a complete valid information bit and output it. At this point, the receiver completes the complete processing link of "cyclic shift detection - cyclic spectrum feature parameter detection - codebook constraint joint decision - shift compensation - noncoherent correlation demodulation".

[0179] This invention provides a frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis. It introduces a dual modulation mechanism of cyclic shift index and cosine frequency index within the FM-DCSK framework, employing block-level processing. By assigning a set of index bits to each transmitted signal block, which are redundantly encoded and mapped to unique frequency and shift parameters, cyclic spectrum features are embedded using a cosine-weighted sequence, and time-domain structural features are embedded using a cyclic shift. At the receiving end, based on intra-block multi-symbol joint processing, two sets of soft information are obtained through shift correlation detection and cyclic spectrum analysis, respectively. Joint decision-making and error correction are performed using codebook constraints, thereby significantly improving spectral efficiency while effectively suppressing multipath and noise interference, ensuring the reliability of index parameter detection. This invention achieves a balance between high spectral efficiency and high reliability, while retaining the inherent advantages of DCSK systems, such as no need for chaotic synchronization and strong multipath resistance.

[0180] Please see Figure 5 The optional embodiments of the present invention also provide corresponding simulation experiments to verify the communication performance of the DCSK system of this scheme.

[0181] Compared with existing CIM-DCSK and MC-DCSK schemes, this invention achieves the same spreading factor L and symbol duration. and the same number of valid information bits Under the same rate comparison caliber, it exhibits superior bit error rate performance. This invention processes DCSK symbols in blocks, with each block containing B symbols (where B=2). Based on the cosine sequence parameters and the reference segment cyclic shift parameters, it can carry additional information bits (each block contains 4 index bits), thus the effective information bits per block are... The block duration is The corresponding effective data rate is The equivalent number of effective bits per symbol is For the CIM-DCSK scheme, each frame consists of 1 data bit and... It consists of 1 index bit, which is equivalent to the number of information bits carried per frame. Under the same symbol structure (reference segment + data segment), the data rate is For the MC-DCSK scheme, let its number of parallel branches be... Each frame carries information bits of 100. ,but Therefore, from the perspective of "number of bits transmitted per unit time" and "number of bits carried per unit symbol", this invention achieves stable rate improvement and bit error rate optimization by adding a block-level payload. Moreover, this improvement does not depend on additional multi-carrier parallel structures or high-dimensional orthogonal codebook extensions, which is beneficial for controlling implementation complexity and synchronization requirements.

[0182] exist Figure 5 It can be intuitively seen that under multipath and Gaussian channels, L=256, The BER curve of this scheme (FM-DCSK with shift-indexed cyclic spectrum analysis) is generally located in the lower left region of both the CIM-DCSK and MC-DCSK curves; in the same Under these conditions, this scheme can achieve a lower bit error rate, or achieve the same target bit error rate at a lower cost. Smaller size results in stronger noise and fading resistance. This is because, in addition to differential correlation demodulation, this invention introduces cyclic shift correlation and cyclic spectrum feature metrics, and utilizes codebook consistency constraints to achieve joint decision-making and error correction, reducing the impact of parameter misjudgment on data demodulation, thereby achieving significant reliability gains at the same rate.

[0183] The frequency modulation differential chaotic phase shift keying communication device based on cyclic spectrum analysis provided in the embodiments of this application is described below. The frequency modulation differential chaotic phase shift keying communication device based on cyclic spectrum analysis described below can be referred to in correspondence with the frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis described above.

[0184] Please see Figure 7 This invention also provides a frequency-modulated differential chaotic phase-shift keying communication device based on cyclic spectrum analysis, the device comprising:

[0185] The transmission block module 301 is used to divide the initial information bit stream into blocks to obtain multiple transmission signal blocks; the information bit stream in each transmission signal block is divided into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase shift keying symbols with a preset number of symbols.

[0186] The modulation module 302 is used to generate an initial transmission sequence of multiple differential chaotic phase shift keying symbols based on the baseband discrete chaotic sequence, data bits and preset spreading factor generated by the chaotic signal generator;

[0187] The codebook encoding module 303 is used to encode the index bits of each transmitted signal block to obtain a codebook sequence; and to extract the first parameter codeword sequence and the second parameter codeword sequence from the codebook index sequence.

[0188] The mapping module 304 is used to map the first parameter codeword sequence into a cosine sequence parameter and the second parameter codeword sequence into a cyclic shift parameter based on the Gray encoding mapping rule; and to convert the cosine sequence parameter into the corresponding frequency parameter based on the preset spreading factor.

[0189] The index embedding module 305 is used to generate a corresponding cosine-weighted sequence based on the frequency parameters, and perform a dot product operation between the cosine-weighted sequence and the corresponding initial transmission sequence to obtain a frequency-modulated transmission sequence; and to perform cyclic shift embedding on the reference segment sequence in the associated frequency-modulated transmission sequence based on the cyclic shift parameters to obtain a cyclic transmission sequence.

[0190] The target transmission sequence generation module 306 is used to concatenate and splice the cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmission signal block to obtain the target transmission sequence.

[0191] Optionally, the codebook encoding module 303 includes:

[0192] The XOR redundancy unit is used to perform an XOR operation on the index bits of each transmitted signal block to obtain the corresponding redundancy check bits; the codebook sequence is composed of four index bits and redundancy check bits in codeword order.

[0193] The parameter codeword unit is used to take the first three bits of the codebook sequence as the first parameter codeword sequence and the last two bits of the codebook sequence as the second parameter codeword sequence.

[0194] Optionally, the modulation module 302 includes:

[0195] The reference segment sequence generation unit is used to generate reference segment sequences for each differential chaotic phase shift keying symbol based on the baseband discrete chaotic sequence generated by the chaotic signal generator and the preset spreading factor.

[0196] The data segment sequence generation unit is used to map the data bits of each differential chaotic phase shift keying symbol to modulation coefficients, and to multiply the reference segment sequence with the corresponding modulation coefficients to obtain the data segment sequence of each differential chaotic phase shift keying symbol.

[0197] The initial transmission sequence construction unit is used to sequentially concatenate the reference segment sequence and the corresponding data segment sequence in the time domain to generate an initial transmission sequence of multiple differential chaotic phase shift keying symbols.

[0198] Optionally, the device also includes:

[0199] The receiving unit 401 is used to receive discrete signals of the target transmission sequence transmitted through the transmission channel and perform symbol synchronization and block processing to obtain multiple received signal blocks;

[0200] The cyclic shift detection unit 402 is used to perform cyclic shift detection on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, and calculate the relevant energy metric of each candidate cyclic shift parameter, thereby establishing a first soft information set;

[0201] Cyclic spectrum analysis unit 403 is used to determine multiple candidate frequency parameters based on candidate cosine sequence parameters in a preset cosine sequence parameter candidate set, perform cyclic spectrum analysis on the received signal block based on each candidate frequency parameter, calculate the block-level cyclic spectrum metric corresponding to each candidate cosine sequence parameter, and thus establish a second soft information set.

[0202] The target parameter determination unit 404 is used to make a joint decision based on the first soft information set and the second soft information set to determine the target cosine sequence parameter and the target shift parameter.

[0203] The demodulation unit 405 is used to perform reverse cyclic shift compensation on the reference segment sequence in the differential chaotic phase shift keying symbol of the associated received signal block using the target shift amount parameter to update the received signal block, and to recover the corresponding data bits by demodulating the updated received signal block.

[0204] The demapping and recovery unit 406 is used to perform demapping and recovery of index bits based on the Gray coding mapping rules, according to the target cosine sequence parameters and the target shift parameters; and to recover the information bits of each received signal block based on the recovered index bits and the corresponding data bits.

[0205] This invention also provides a computer-readable storage medium storing a computer program or instructions thereon, which, when executed by a processor, implements the steps of any of the frequency modulation differential chaotic phase shift keying communication methods based on cyclic spectrum analysis as described above.

[0206] This invention also provides a computer program product, including a computer program or instructions, which, when executed by a processor, implement the steps of any of the frequency modulation differential chaotic phase shift keying communication methods based on cyclic spectrum analysis as described above.

[0207] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0208] The terms “first,” “second,” etc., used in this application's specification are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0209] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0210] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0211] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0212] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0213] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A frequency-modulated differential chaotic phase-shift keying communication method based on cyclic spectrum analysis, characterized in that, The method includes: The initial information bit stream is divided into blocks to obtain multiple transmission signal blocks; the information bit stream in each transmission signal block is divided into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase shift keying symbols with a preset number of symbols; Based on the baseband discrete chaotic sequence generated by the chaotic signal generator, the data bits, and the preset spreading factor, an initial transmission sequence of multiple differential chaotic phase shift keying symbols is generated. The index bits of each transmitted signal block are encoded using a codebook to obtain a codebook sequence; the first parameter codeword sequence and the second parameter codeword sequence are extracted from the codebook sequence. Based on the Gray encoding mapping rule, the first parameter codeword sequence is mapped to a cosine sequence parameter, and the second parameter codeword sequence is mapped to a cyclic shift parameter; based on the preset spreading factor, the cosine sequence parameter is converted into the corresponding frequency parameter. A corresponding cosine-weighted sequence is generated based on the frequency parameters, and the cosine-weighted sequence is multiplied by the corresponding initial transmission sequence to obtain a frequency-modulated transmission sequence; a cyclic shift embedding is performed on the reference segment sequence in the associated frequency-modulated transmission sequence based on the cyclic shift parameters to obtain a cyclic transmission sequence; The target transmission sequence is obtained by concatenating the cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmission signal block.

2. The frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis according to claim 1, characterized in that, The method further includes: The discrete signals of the target transmission sequence transmitted through the transmission channel are received and symbol synchronization and block processing are performed to obtain multiple received signal blocks; Based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, cyclic shift detection is performed on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block, and the relevant energy metric of each candidate cyclic shift parameter is calculated, thereby establishing the first soft information set; Multiple candidate frequency parameters are determined based on the candidate cosine sequence parameters in the preset cosine sequence parameter candidate set. Cyclic spectrum analysis is performed on the received signal block based on each candidate frequency parameter to calculate the block-level cyclic spectrum metric corresponding to each candidate cosine sequence parameter, thereby establishing a second soft information set. Based on the first soft information set and the second soft information set, a joint decision is made to determine the target cosine sequence parameter and the target shift parameter; The target shift parameter is used to perform reverse cyclic shift compensation on the reference segment sequence in the differential chaotic phase shift keying symbol of the associated received signal block to update the received signal block, and the corresponding data bits are recovered by correlation demodulation of the updated received signal block. Based on the Gray encoding mapping rules, the index bits are recovered by inverse mapping according to the target cosine sequence parameters and the target shift parameters; the information bits of each received signal block are recovered based on the recovered index bits and the corresponding data bits.

3. The frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis according to claim 1, characterized in that, The index bits have four bits; the step of encoding the index bits of each transmitted signal block into a codebook sequence; and extracting the first parameter codeword sequence and the second parameter codeword sequence from the codebook sequence includes: Perform an XOR operation on the index bits of each transmitted signal block to obtain the corresponding redundancy check bits; the codebook sequence is composed of the four index bits and the redundancy check bits in codeword order; The first three bits of the codebook sequence are used as the first parameter codeword sequence, and the last two bits of the codebook sequence are used as the second parameter codeword sequence.

4. The frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis according to claim 1, characterized in that, The cosine-weighted sequence is represented as follows: In the formula: For the first k The cosine-weighted sequence of differential chaotic phase-shift keying symbols in the th... n Cosine weighted values ​​at each sampling point; For the first k The phase value of a differential chaotic phase shift keying symbol; For normalized frequency parameters, , For the parameters of the cosine sequence, It is the spreading factor; The frequency-modulated transmission sequence is represented as follows: In the formula: For the first k The frequency modulation transmission sequence of the differential chaotic phase shift keying symbols in the first... n Discrete signals at each sampling point; For the first k The initial emission sequence of differential chaotic phase shift keying symbols in the th... n Discrete signals at each sampling point; The reference segment sequence in the cyclic emission sequence is represented as follows: In the formula: For the first k The cyclic emission sequence of differential chaotic phase-shift keying symbols in the first... n Discrete signals at each sampling point; This is the cyclic shift parameter.

5. The frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis according to claim 1, characterized in that, The step of generating an initial transmission sequence of multiple differential chaotic phase shift keying symbols based on the baseband discrete chaotic sequence generated by the chaotic signal generator, the data bits, and the preset spreading factor includes: Based on the baseband discrete chaotic sequence generated by the chaotic signal generator and the preset spreading factor, a reference segment sequence for each differential chaotic phase shift keying symbol is generated. The data bits of each differential chaotic phase shift keying symbol are mapped to modulation coefficients, and the reference segment sequence is multiplied with the corresponding modulation coefficients to obtain the data segment sequence of each differential chaotic phase shift keying symbol. The reference segment sequence and the corresponding data segment sequence are concatenated sequentially in the time domain to generate an initial transmission sequence of multiple differential chaotic phase shift keying symbols.

6. The frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis according to claim 2, characterized in that, The step of performing cyclic shift detection on the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, and calculating the relevant energy metric for each candidate cyclic shift parameter to establish the first soft information set includes: Based on each candidate cyclic shift parameter in the preset cyclic shift candidate set, the reference segment sequence in the differential chaotic phase shift keying symbol of the received signal block is subjected to reverse cyclic compensation to obtain the real reference segment sequence. Based on the real reference segment sequence and its corresponding data segment sequence, calculate the cross-correlation value of each candidate cyclic shift parameter; based on the cross-correlation value, calculate the energy metric of each candidate cyclic shift parameter; The energy measures of all differential chaotic phase shift keying symbols in each received signal block under the corresponding candidate cyclic shift parameters are accumulated to obtain the relevant energy measures of each received signal block under each candidate cyclic shift parameter. Based on the relevant energy metric of each received signal block under each candidate cyclic shift parameter, a first soft information set for each received signal block is established.

7. The frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis according to claim 2, characterized in that, The step of determining multiple candidate frequency parameters based on candidate cosine sequence parameters in a preset candidate set of cosine sequence parameters, performing cyclic spectrum analysis on the received signal block based on each candidate frequency parameter, and calculating the block-level cyclic spectrum metric corresponding to each candidate cosine sequence parameter to establish a second soft information set includes: Calculate the corresponding candidate frequency parameter based on each candidate cosine sequence parameter in the preset candidate set of cosine sequence parameters; The received signal block is segmented and windowed to obtain multiple received signal segments; Based on each candidate frequency parameter, the received signal segment is subjected to positive and negative half-cycle frequency shift to obtain two corresponding frequency shift components; the two corresponding frequency shift components are subjected to Fourier transform and cyclic spectrum correlation function estimation to obtain the cyclic spectrum correlation estimate of the corresponding received signal segment; Energy aggregation calculation is performed on the cyclic spectrum correlation estimate within the preset frequency domain to obtain the segment-level metric of the corresponding received signal segment; The mean of the segment-level metric for all received signal segments of each received signal block is calculated to obtain the block-level cyclic spectrum metric for each received signal block under each candidate cosine sequence parameter. Based on the block-level cyclic spectrum metric of each received signal block under each candidate cosine sequence parameter, a second soft information set for each received signal block is established.

8. A frequency-modulated differential chaotic phase-shift keying communication device based on cyclic spectrum analysis, characterized in that, The device includes: The transmission block module is used to divide the initial information bit stream into blocks to obtain multiple transmission signal blocks; the information bit stream in each transmission signal block is divided into corresponding data bits and index bits; wherein, in each transmission signal block, the corresponding data bits are carried by differential chaotic phase shift keying symbols with a preset number of symbols; The modulation module is used to generate an initial transmission sequence of multiple differential chaotic phase shift keying symbols based on the baseband discrete chaotic sequence generated by the chaotic signal generator, the data bits, and the preset spreading factor; The codebook encoding module is used to encode the index bits of each transmitted signal block to obtain a codebook sequence; and to extract the first parameter codeword sequence and the second parameter codeword sequence from the codebook sequence. The mapping module is used to map the first parameter codeword sequence into a cosine sequence parameter and the second parameter codeword sequence into a cyclic shift parameter based on the Gray encoding mapping rule; and to convert the cosine sequence parameter into a corresponding frequency parameter based on the preset spreading factor. The index embedding module is used to generate a corresponding cosine-weighted sequence based on the frequency parameters, and perform a dot product operation between the cosine-weighted sequence and the corresponding initial transmission sequence to obtain a frequency-modulated transmission sequence; and to perform cyclic shift embedding on the reference segment sequence in the associated frequency-modulated transmission sequence based on the cyclic shift parameters to obtain a cyclic transmission sequence. The target transmission sequence generation module is used to concatenate and splice the cyclic transmission sequences of all differential chaotic phase shift keying symbols in each transmission signal block to obtain the target transmission sequence.

9. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed by the processor, they implement the steps of the frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis as described in any one of claims 1-7.

10. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by the processor, they implement the steps of the frequency modulation differential chaotic phase shift keying communication method based on cyclic spectrum analysis as described in any one of claims 1-7.

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