DCSK communication method based on non-constant envelope three-dimensional constellation diagram and related device

Abstract

The invention discloses a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram and a related device, and the method comprises the steps: carrying out the cyclic shift of a first-stage chaotic signal, obtaining a first shift chaotic signal group, and mapping a target information bit into a three-dimensional constellation symbol with a non-constant envelope; modulating the non-constant enveloped three-dimensional constellation symbol and the first shift chaotic signal group into an information bearing signal; transmitting a transmission signal generated by the first chaotic signal and the information bearing signal to a receiver, obtaining and filtering a receiving signal, generating a receiving reference signal and a receiving bearing signal, and circularly shifting the receiving reference signal to obtain a second shifting chaotic signal group; the correlation operation receives the bearer signal and the second shift chaotic signal group to obtain a correlation quantity, and the channel compensates the correlation quantity to obtain a decision vector and estimate a transmission information bit. In the invention, a three-dimensional constellation with a non-constant envelope is introduced, and channel compensation is carried out on the system by using the received reference signal, so that the transmission efficiency and the reliability are effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and in particular, to a DCSK communication method and related devices based on a non-constant envelope three-dimensional constellation diagram. Background Art

[0002] With the rapid development of the information industry, mobile Internet services have witnessed an explosive growth. The massive service data poses severe challenges to the transmission rate, spectrum efficiency, and reliability of the next-generation wireless communication network. Therefore, the research on low-power, low-cost, highly efficient, and reliable wireless communication technologies is extremely urgent. Chaos theory is an important branch of nonlinear science, which originated from the sensitivity of nonlinear systems to initial conditions. As an interdisciplinary theory, chaos theory has been widely applied in fields such as meteorology, biology, economics, physics, and telecommunications. Chaos communication is a scientific theory that applies chaotic signals to the field of communication, mainly utilizing the good characteristics of chaotic signals such as determinism, initial value sensitivity, wide spectrum, and noise-like. Due to these inherent characteristics, chaos communication systems have potential advantages in aspects such as secure communication, anti-interference, and anti-multipath fading.

[0003] Currently, the research on chaos communication in wireless communication mainly focuses on chaotic digital modulation. Differential Chaos Shift Keying (DCSK) technology has become a widely studied non-coherent chaotic digital modulation scheme due to its advantages of low power consumption and low cost. However, the existing DCSK schemes still have deficiencies in communication performance such as transmission rate and transmission reliability, and it is difficult to meet the requirements of the new generation of wireless communication networks. Therefore, it is urgent to further optimize the DCSK scheme to improve its communication performance. Summary of the Invention

[0004] The present invention provides a DCSK communication method and related devices based on a non-constant envelope three-dimensional constellation diagram, which are used to solve the technical problem that the existing DCSK schemes still have deficiencies in communication performance such as transmission rate and transmission reliability and are difficult to meet the requirements of the new generation of wireless communication networks.

[0005] The present invention provides a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram, and the method includes:

[0006] Performing a cyclic shift operation on a first-level chaotic signal with a length generated by a chaos generator to obtain a first shifted chaotic signal group; wherein, the first shifted chaotic signal group includes a first chaotic signal, a second chaotic signal, and a third chaotic signal;

[0007] ​Map the target information bits into three-dimensional constellation symbols with non-constant envelope, and generate an information-bearing signal through information modulation by the three-dimensional constellation symbols with non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal;

[0008] Generate a transmission signal based on the first chaotic signal and the information-bearing signal, and transmit the transmission signal to a receiver to generate a received signal;

[0009] In the receiver, filter the received signal to obtain a received reference signal and a received bearing signal, perform a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group;

[0010] Perform a correlation operation through the received bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and perform a channel compensation operation on the correlation quantity to obtain a normalized decision vector;

[0011] Perform information recovery analysis on the normalized decision vector to estimate the transmitted information bits.

[0012] Further, the step of performing a cyclic shift operation on the first-level chaotic signal generated by the chaotic generator with a length of to obtain the first shifted chaotic signal group includes:

[0013] Perform a cyclic shift operation on the first-level chaotic signal generated by the chaotic generator with a length of to obtain a second-level chaotic signal;

[0014] Superimpose the first-level chaotic signal and the second-level chaotic signal to obtain the first chaotic signal;

[0015] Perform a cyclic shift operation on the first chaotic signal through a cyclic shift converter to obtain the second chaotic signal and the third chaotic signal.

[0016] Further, the step of mapping the target information bits into three-dimensional constellation symbols with non-constant envelope and generating an information-bearing signal through information modulation by the three-dimensional constellation symbols with non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal includes:

[0017] Map the target information bits into three-dimensional constellation symbols with non-constant envelope through a three-dimensional constellation mapper;

[0018] Perform information modulation on the amplitudes of the three-dimensional constellation symbols with non-constant envelope on the x-axis, y-axis, and z-axis by the first chaotic signal, the second chaotic signal, and the third chaotic signal respectively to generate an information-bearing signal.

[0019] Further, the step of generating a transmission signal based on the first chaotic signal and the information-bearing signal and transmitting the transmission signal to a receiver to generate a received signal includes:

[0020] Performing a pulse shaping operation on the first chaotic signal and the information-bearing signal to respectively obtain a pulse reference signal and a pulse-bearing signal;

[0021] Based on a preset carrier frequency, superimposing the pulse reference signal and the pulse-bearing signal to obtain a transmission signal;

[0022] Transmitting the transmission signal through a wireless channel to a receiver to generate a received signal.

[0023] Further, the second shifted chaotic signal group includes a received reference signal, a three-stage chaotic signal, a fourth chaotic signal, and a fifth chaotic signal; the step of filtering the received signal in the receiver to obtain a received reference signal and a received-bearing signal and performing a cyclic shift operation on the received reference signal to obtain the second shifted chaotic signal group includes:

[0024] In the receiver, filtering the received signal through a matched filter to obtain a received reference signal and a received-bearing signal;

[0025] Performing a cyclic shift operation of length on the received reference signal through a cyclic shift converter to obtain a three-stage chaotic signal;

[0026] Performing a cyclic shift operation of length and on the received reference signal through a cyclic shift converter to respectively construct a first reference signal and a second reference signal;

[0027] Performing Schmidt orthonormalization on the received reference signal, the first reference signal, and the second reference signal to recover the fourth chaotic signal and the fifth chaotic signal.

[0028] Further, the step of performing a correlation operation on the received-bearing signal and the second shifted chaotic signal group to obtain a correlation quantity and performing a channel compensation operation on the correlation quantity to obtain a normalized decision vector includes:

[0029] Performing a correlation operation on the received-bearing signal with the received reference signal, the fourth chaotic signal, and the fifth chaotic signal respectively to generate an initial decision vector;

[0030] Performing a correlation operation on the received reference signal and the three-stage chaotic signal to obtain a channel power gain sum value;

[0031] Perform a channel compensation operation on the initial decision vector based on the channel power gain and value to obtain a normalized decision vector.

[0032] Further, the step of performing information recovery analysis on the normalized decision vector to estimate the transmitted information bits includes:

[0033] Based on the minimum Euclidean distance algorithm, estimate the label of the three-dimensional constellation symbol with non-constant envelope through the normalized decision vector to obtain an estimated label;

[0034] Perform a bit recovery operation through the estimated label to estimate the transmitted information bits.

[0035] The present invention also provides a DCSK communication device based on a three-dimensional constellation diagram with non-constant envelope, and the device includes:

[0036] A cyclic shift unit for performing a cyclic shift operation on a first-level chaotic signal with a length generated by a chaotic generator to obtain a first shifted chaotic signal group; wherein, the first shifted chaotic signal group includes a first chaotic signal, a second chaotic signal, and a third chaotic signal;

[0037] A mapping unit for mapping the target information bits into three-dimensional constellation symbols with non-constant envelope through a three-dimensional constellation mapper, and generating an information-bearing signal through information modulation using the three-dimensional constellation symbols with non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal;

[0038] A transmission unit for generating a transmission signal based on the first chaotic signal and the information-bearing signal, and transmitting the transmission signal to a receiver to generate a received signal;

[0039] A receiving and processing unit for filtering the received signal in the receiver to obtain a received reference signal and a received bearing signal, and performing a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group;

[0040] A channel compensation unit for performing a correlation operation on the received bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing a channel compensation operation on the correlation quantity to obtain a normalized decision vector;

[0041] An information recovery unit for performing information recovery analysis on the normalized decision vector to estimate the transmitted information bits.

[0042] The present invention also provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the steps of any one of the above-mentioned DCSK communication methods are implemented.​

[0043] The present invention also provides a computer-readable storage medium, on which a computer program is stored. The computer program, when executed by a processor, implements the steps of the DCSK communication method described in any one of the above.

[0044] As can be seen from the above technical solutions, the present invention has the following advantages:

[0045] The present invention provides a DCSK communication method and related device based on a non-constant envelope three-dimensional constellation diagram. The method includes: performing a cyclic shift operation on a first-level chaotic signal generated by a chaotic generator with a length of to obtain a first shifted chaotic signal group; wherein the first shifted chaotic signal group includes a first chaotic signal, a second chaotic signal, and a third chaotic signal; mapping target information bits into three-dimensional constellation symbols with a non-constant envelope, and generating an information-bearing signal through information modulation by the three-dimensional constellation symbols with a non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal; generating a transmission signal based on the first chaotic signal and the information-bearing signal, and transmitting the transmission signal to a receiver to generate a received signal; in the receiver, filtering the received signal to obtain a received reference signal and a received bearing signal, performing a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group; performing a correlation operation on the received bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing a channel compensation operation on the correlation quantity to obtain a normalized decision vector; performing information recovery analysis on the normalized decision vector to estimate the transmitted information bits.

[0046] In the present invention, a non-constant envelope three-dimensional constellation is introduced, which effectively increases the minimum Euclidean distance between symbols. At the same time, a cyclic shift converter and a correlator are designed to utilize the information carried by the received reference signal itself to estimate the channel power gain and value, and perform channel compensation on the system, thereby effectively improving the transmission efficiency and transmission reliability of the system, achieving better communication performance, and further solving the technical problem that the existing DCSK scheme still has deficiencies in communication performance such as transmission rate and transmission reliability and is difficult to meet the requirements of the new generation of wireless communication networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions that can be implemented in combination with the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0048] Figure 1Flow chart of steps of a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram provided by an embodiment of the present invention;

[0049] Figure 2 Structural diagram of a transmitter and a receiver of a DCSK system based on a non-constant envelope three-dimensional constellation diagram provided by an embodiment of the present invention;

[0050] Figure 3 Schematic structural diagram of a non-constant envelope three-dimensional constellation provided by an embodiment of the present invention;

[0051] Figure 4 Schematic diagram of data processing of a cyclic shift changer and a correlator provided by an embodiment of the present invention;

[0052] Figure 5 BER performance comparison diagram between a 3DNCEC-M-DCSK system and 2DCEC-M-DCSK systems, 2DNCEC-M-DCSK systems, and 3DCEC-M-DCSK systems provided by an embodiment of the present invention;

[0053] Figure 6 Symbol error rate performance comparison diagram between a 3DNCEC-M-DCSK system and a 3DNCEC-M-DCSK (without CSC) system provided by an embodiment of the present invention;

[0054] Figure 7 Structural block diagram of a DCSK communication device based on a non-constant envelope three-dimensional constellation diagram provided by an embodiment of the present invention;

[0055] Figure 8 Structural diagram of a transmitter and a receiver of a typical DCSK system provided by an embodiment of the present invention in combination with the prior art;

[0056] Figure 9 Structural diagram of a transmitter and a receiver of a 2DCEC-M-DCSK system provided by an embodiment of the present invention in combination with the prior art;

[0057] Figure 10 Schematic diagram of the constellation diagram structure and decision region of a 2DCEC-M-DCSK system provided by an embodiment of the present invention in combination with the prior art;

[0058] Figure 11 Structural diagram of a transmitter and a receiver of a 2DNCEC-M-DCSK system provided by an embodiment of the present invention in combination with the prior art;

[0059] Figure 12 Schematic diagram of the constellation diagram structure and decision region of a 2DNCEC-M-DCSK system provided by an embodiment of the present invention in combination with the prior art;

[0060] Figure 13 Structural diagrams of the transmitter and receiver of the 3DCEC-M-DCSK system provided by the embodiments of the present invention in combination with the prior art;

[0061] Figure 14 Schematic diagram of the constellation structure of the 3DCEC-M-DCSK system provided by the embodiments of the present invention in combination with the prior art. Detailed implementation manners

[0062] The embodiments of the present invention provide a DCSK communication method and related devices based on a non-constant envelope three-dimensional constellation diagram, which are used to solve the technical problem that the existing DCSK solutions still have deficiencies in communication performance such as transmission rate and transmission reliability, and it is difficult to meet the requirements of the new generation of wireless communication networks.

[0063] In order to make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0064] Please refer to Figures 8 - 14 , and the communication performance of the DCSK system that can be realized by the prior art will be further described below in combination with the processing flow of the transmitter and receiver of the DCSK system that can be realized by the prior art.

[0065] 1. Typical DCSK system

[0066] Please refer to Figure 8 , the transmitter first uses a chaos generator to generate a chaos signal with a length of , where the spreading factor of the DCSK system is defined as . In a typical DCSK system, the symbol duration of each frame of transmitted symbols is equally divided into two symbol periods. The chaos signal is transmitted in the first symbol period, and the chaos signal carrying the information bit is transmitted in the second symbol period. Specifically, represents the transmitted information bit, where . If , the information-bearing signal transmits a copy signal of , otherwise the information-bearing signal transmits the negative polarity signal of .

[0067] Among them, the - transmitted signal of the typical DCSK system is expressed as:

[0068] (1)

[0069] The transmitted signal is processed by delay and modulation to obtain the transmitted signal. After being transmitted through the wireless channel, the transmitted signal reaches the receiver. The signal received by the receiver can be expressed as:

[0070] (2)

[0071] where represents the convolution operation; and are respectively - the channel coefficient and delay of the path; is additive white Gaussian noise with zero mean and variance

[0072] To recover the information bits, the received signal and its delayed signal version need to be transmitted to the correlator to obtain the decision variable , that is,

[0073] (3)

[0074] Finally, the decision variable output by the correlator is input to the decision maker to recover the information bits , and the decision rule is as follows:

[0075] (4)

[0076] In a typical DCSK system, one symbol duration is divided into two periods. The first period is used to transmit the reference signal, and the second period is used to transmit the signal carrying information. However, this operation makes half of the time and energy used to transmit the reference signal, resulting in relatively low energy efficiency and spectral efficiency of the system.

[0077] 2. 2DCEC-M-DCSK System

[0078] Compared with the typical DCSK system, the two-dimensional constant-envelope constellation-assisted multi - DCSK (2DCEC-M-DCSK) system greatly improves the data transmission rate and transmission reliability. Among them, the 2DCEC-M-DCSK system can transmit bits within one symbol period, thus improving the data transmission rate. Please refer to Figure 9, the working principle of the 2DCEC-M-DCSK system is as follows.

[0079] First, the information bits can be mapped to two-dimensional constellation symbols , where represents the label of the constellation symbol, , and M is the modulation order; and represent the real and imaginary parts of the two-dimensional constellation symbol respectively. Please refer to Figure 10 , Figure 10 shows one of the constellation diagram structures of the 2DCEC-M-DCSK system in the case of

[0080] Then the chaos generator generates a chaotic reference signal , and this signal is converted into another orthogonal signal through the Hilbert transformer, thus generating two orthogonal chaotic signals. In order to transmit the two-dimensional coordinate information, the signals and carry the real and imaginary parts of the constellation symbol respectively, thus obtaining the information-bearing signal, that is, . Similarly, in the 2DCEC-M-DCSK system, the reference signal is sent in the first half of the symbol period, while the information-bearing signal is sent in the second half of the symbol period.

[0081] Among them, the transmitted signal can be expressed as:

[0082] (1)

[0083] At the receiving end, the Hilbert transform is performed on the noise-corrupted reference signal to obtain the signal , and then the signals and are respectively correlated with the noise-corrupted information-bearing signal to obtain the decision vector

[0084] (2)

[0085] Based on the obtained decision vector, and using the decision region shown in Figure 10 to determine the estimated value of the bit information.

[0086] For the 2DCEC-M-DCSK system, it does improve the transmission efficiency of the typical DCSK system. However, due to the relatively small minimum Euclidean distance between adjacent symbols, the performance of the 2DCEC-M-DCSK system is limited.

[0087] 3. 2DNCEC-M-DCSK System

[0088] Different from the 2DCEC-M-DCSK system, the Two-dimensional non-constant-envelope constellation-assisted M-DCSK (2DNCEC-M-DCSK) system introduces a two-dimensional non-constant-envelope constellation, and the system also needs to insert pilot symbols for channel estimation. Among them, since the channel is slowly fading, it is reasonable that the channel parameters remain unchanged within some symbol durations. The following briefly introduces the differences between the 2DCEC-M-DCSK system and the 2DNCEC-M-DCSK system.

[0089] Please refer to Figure 11 and Figure 12 , taking the QAM constellation as an example, where M = 16; the 2DNCEC-M-DCSK system estimates the transmitted information bits by estimating the channel power gain and . Assuming the transmitted pilot symbol is , due to the symmetry of the decision quantity, analyzing one of the coordinate value decision quantities can obtain:

[0090] (7)

[0091] Therefore, if the least squares (LS) estimator is adopted, the channel parameter estimation is:

[0092] (8)

[0093] The LS estimator provides good estimation under high signal-to-noise ratio conditions, but under low signal-to-noise ratio conditions, its mean square error is relatively large. Here, using the symbol (1,0) as the pilot symbol can minimize the noise.

[0094] For the 2DNCEC-M-DCSK system, it improves the minimum Euclidean distance between adjacent symbols to a certain extent. However, the constellation dimension limits the size of the minimum Euclidean distance between adjacent symbols. In addition, the system needs to insert additional pilot symbols for channel estimation, thus reducing the transmission efficiency of the system.

[0095] 4. 3DCEC-M-DCSK System

[0096] Due to the small minimum Euclidean distance of the two-dimensional constellation, which results in a relatively high lower bound of the system bit error rate, a three-dimensional constant-envelope constellation-assisted multi-carrier differential chaos shift keying (3DCEC-M-DCCK) system is proposed.

[0097] Please refer to Figure 13 and Figure 14 , where the (a), (b), and (c) corresponding to Fig. (14) respectively correspond to the constant-envelope three-dimensional constellations with modulation orders , and Specifically, the transmitter of the 3DCEC-M-DCCK system first generates a chaotic signal , expressed as:

[0098] .(9)

[0099] The chaotic signal can be cyclically shifted to obtain chaotic signals and , which can be specifically expressed as:

[0100] (10)

[0101] (11)

[0102] where and are the number of cyclic shift positions for obtaining the chaotic signals and . Due to the good cross-correlation between chaotic signals, the chaotic signals , and can be approximated as orthogonal to each other (i.e., , and ).

[0103] Next, Schmidt orthogonalization is performed on the chaotic signals , and to ensure the strict orthogonality between chaotic signals. Then, the information bits are mapped to a three-dimensional constellation symbol , where is the label of the three-dimensional constellation symbol, M is the modulation order, and . , and The values respectively represent axis, axis and axis amplitudes, which are respectively carried by the chaotic signals , and .

[0104] Therefore, the information-bearing signal of the 3DCEC-M-DCSK system can be expressed as . Then, the reference signal and the information-bearing signal after pulse shaping are respectively expressed as and , where is the unit power pulse shaping function; represents the energy of the transmitted symbol; is the chip time.

[0105] Therefore, the transmitted signal of the 3DCEC-M-DCSK system can be expressed as:

[0106] (12)

[0107] where is the carrier frequency, and must satisfy .

[0108] At the receiver, the received signal passes through a matched filter to obtain the noise-corrupted reference signal and the information-bearing signal . Then, the reference signal is subjected to cyclic shift operations of lengths and respectively to construct the reference signals and . To estimate the transmitted information bits, by performing correlation operations on the received information-bearing signal with the reference signals , , respectively, the decision vector can be obtained, where ; ; .

[0109] Based on the minimum Euclidean distance detection, the label of the received three-dimensional constellation symbol can be estimated, as follows

[0110] ,(13)

[0111] where This is a modulo operation.

[0112] Finally, the transmitted information bits can be recovered based on the bits corresponding to the estimated tag

[0113] For the 3DCEC-M-DCSK system, it extends the constellation dimension to three dimensions, effectively increasing the minimum Euclidean distance between symbols. However, the space utilization rate of the constellation is still low, and the advantages of the three-dimensional constellation are not fully utilized, thus affecting the transmission reliability of the system.

[0114] In view of the problem of insufficient communication performance existing in the DCSK system that can be achieved by combining the prior art, the present invention proposes a three-dimensional non-constant-envelope constellation-assisted multi-carrier DCSK (Three-dimensional non-constant-envelope constellation-assisted M-DCSK, 3DNCEC-M-DCSK) system to optimize the traditional DCSK system, so as to further improve the transmission efficiency and transmission reliability of the system.

[0115] Please refer to Figure 1 and Figure 2 , the present invention provides a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram, and the method includes:

[0116] Step 101: Perform a cyclic shift operation on the first-level chaotic signal generated by the chaotic generator with a length of to obtain a first shifted chaotic signal group.

[0117] Further, step 101 includes:

[0118] First, perform a cyclic shift operation with a length of on the first-level chaotic signal generated by the chaotic generator to obtain a second-level chaotic signal ; ;

[0119] Among them, the first-level chaotic signal is expressed as:

[0120] (14)

[0121] The second-level chaotic signal is expressed as:

[0122] (15)

[0123] Among them, needs to meet the condition of being divisible by 2.

[0124] ​Next, superimpose the first-level chaotic signal and the second-level chaotic signal to obtain the first chaotic signal , that is:

[0125] (16)

[0126] Then, perform a cyclic shift operation of length and on the first chaotic signal through a cyclic shift transformer to obtain the second chaotic signal and the third chaotic signal . Among them, is the floor operation.

[0127] It should be noted that due to the good cross-correlation characteristics of chaotic signals, the chaotic signals , and can be approximated as orthogonal to each other (i.e., , and ). Therefore, Schmidt orthogonalization can be performed on the chaotic signals , and to ensure the strict orthogonality satisfied by the chaotic signals with each other. Normalize the energy of the obtained chaotic signals to 1, that is: .

[0128] In this step, based on the improved three-dimensional orthogonal basis structure, a cyclic shift transformer is introduced to obtain the first group of shifted chaotic signals, that is, the first chaotic signal , the second chaotic signal and the third chaotic signal ; particularly, the first chaotic signal is composed of chaotic signals and with a shift number difference of half superimposed.

[0129] Step 102, map the target information bits into three-dimensional constellation symbols with non-constant envelope, and generate an information-bearing signal through information modulation with the three-dimensional constellation symbols with non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal.

[0130] In this step, the target information bits are mapped into three-dimensional constellation symbols with non-constant envelope through a three-dimensional constellation mapper, which can effectively increase the minimum Euclidean distance between symbols (i.e., the distance between adjacent constellation points of information symbol mapping); among them, is the label of the three-dimensional constellation symbol, is the modulation order; , and respectively represent the amplitude of the axis, the amplitude of the

[0131] axis and .

[0132] Step 103: Generate a transmission signal based on the first chaotic signal and the information-bearing signal, and transmit the transmission signal to a receiver to generate a received signal.

[0133] In this step, first perform pulse shaping operations on the first chaotic signal and the information-bearing signal to respectively obtain a pulse reference signal and a pulse-bearing signal ; where represents the unit power pulse shaping function, represents the chip time.

[0134] Then, based on a preset carrier frequency, superimpose the pulse reference signal and the pulse-bearing signal to obtain the transmission signal; where the transmission signal is expressed as:

[0135] (17)

[0136] In the formula: is the carrier frequency, and must satisfy .

[0137] Finally, transmit the transmission signal through a wireless channel to the receiver to generate a received signal .

[0138] Step 104: In the receiver, filter the received signal to obtain a received reference signal and a received bearing signal, and perform a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group.

[0139] Among them, the second shifted chaotic signal group includes the received reference signal , the third chaotic signal , the fourth chaotic signal and the fifth chaotic signal .

[0140] Step 104 specifically includes:

[0141] Sub-step 1041: In the receiver, the received signal is filtered by a matched filter to obtain a received reference signal contaminated by noise and a received carrier signal ;

[0142] Sub-step 1042: The received reference signal is subjected to a cyclic shift operation of length by a cyclic shift converter to obtain a three-stage chaotic signal ;

[0143] It should be noted that channel compensation requires obtaining the channel power gain sum, rather than the fading coefficient of each channel, which is different from the traditional channel estimation in a coherent communication system. In particular, in the present invention, without inserting any additional pilot symbols, the information carried by the received reference signal itself is effectively utilized through a cyclic displacement converter to estimate the channel power sum value. The specific operation is as follows: The received reference signal is subjected to a cyclic displacement operation of length to obtain a special chaotic signal ;

[0144] Please refer to Figure 4 , which can be approximately regarded as the superposition of the first chaotic signal and noise ; Immediately afterwards, the received reference signal is subjected to a cyclic shift operation of length to obtain a three-stage chaotic signal , where the three-stage chaotic signal is composed of the superposition of the first chaotic signal and the shifted different noise . It should be particularly noted that the length of the first chaotic signal remains unchanged after being subjected to a cyclic shift operation of length , as shown below:

[0145] (18)

[0146] Among them, represents the cyclic shift operation of length performed on .

[0147] Sub-step 1043: The received reference signal is subjected to cyclic shift operations of lengths and by a cyclic shift converter to respectively construct a first reference signal and a second reference signal ;

[0148] Sub-step 1044, perform Schmidt orthogonalization on the received reference signal , the first reference signal and the second reference signal to recover the fourth chaotic signal and the fifth chaotic signal .

[0149] Step 105, perform a correlation operation on the received carrier signal and the second shifted chaotic signal group to obtain a correlation quantity, and perform a channel compensation operation on the correlation quantity to obtain a normalized decision vector.

[0150] This step specifically includes:[[]]

[0151] Sub-step 1051, perform a correlation operation on the received carrier signal with the received reference signal , the fourth chaotic signal and the fifth chaotic signal respectively to generate an initial decision vector;

[0152] It should be noted that in order to estimate the transmitted information bits, it is necessary to perform a correlation operation on the received received carrier signal with the chaotic signals , and respectively, and an initial decision vector can be obtained, where ; ; .

[0153] Sub-step 1052, perform a correlation operation on the received reference signal and the third-level chaotic signal to obtain the channel power gain sum value;

[0154] In this sub-step, by performing a correlation operation on and , the variable can be obtained, that is,

[0155] (19)

[0156] Furthermore, the variable can be approximated as:

[0157] (20)

[0158] In the formula, represents the fading coefficient under the th path, represents the Gaussian white noise of the received reference signal, then from Shifted Gaussian white noise obtained by performing a cyclic shift operation.

[0159] Through analysis, it is possible to use the variable as the estimated channel power gain and value, that is .

[0160] Sub-step 1053: Perform channel compensation operation on the initial decision vector based on the channel power gain and value to obtain a normalized decision vector. Among them, the normalized decision vector can be expressed as .

[0161] Step 106: Perform information recovery analysis on the normalized decision vector to estimate the transmitted information bits.

[0162] It should be noted that in this embodiment, two different non-constant envelope three-dimensional constellations are used as examples: the cross-lattice constellation with a modulation order of 32 as shown in Figure 3 (a) and the perfect lattice constellation with a modulation order of 64 as shown in Figure 3 (b). By calculating the minimum Euclidean distance between adjacent mapped symbols, it can be seen that the introduced non-constant envelope constellation achieves a larger minimum Euclidean distance at the same modulation order.

[0163] In this step, based on the minimum Euclidean distance algorithm, the label of the three-dimensional constellation symbol with non-constant envelope is estimated through the normalized decision vector to obtain the estimated label , as follows:

[0164] (21)

[0165] Where: is the modulo operation.

[0166] Finally, the transmitted information bits can be recovered based on the bits corresponding to the estimated label .

[0167] The 3DNCEC-M-DCSK system provided by the present invention introduces a non-constant envelope three-dimensional constellation, and at the same time designs a cyclic shift changer and a correlator to perform channel compensation on the system, thereby effectively improving the transmission efficiency and transmission reliability of the system. The following combines Figure 5 and Figure 6 to further analyze the performance of the 3DNCEC-M-DCSK system.

[0168] 1) Regarding transmission efficiency: Assume that in the 2DNCEC-M-DCSK system, a pilot symbol is inserted at the end of every G information-bearing signals. Then, compared with the 2DNCEC-M-DCSK system, the 3DNCEC-M-DCSK system of the present invention does not require the assistance of inserting pilot symbols, thereby achieving a higher data transmission rate and spectral efficiency. The specific comparison data of the transmission efficiency is shown in Table 1.

[0169] Table 1 Comparison of transmission efficiency and spectral efficiency between 3DNCEC-M-DCSK system and 2DNCEC-M-DCSK system

[0170]

[0171] 2) Regarding transmission reliability: Compared with the 2DCEC-M-DCSK system, 2DNCEC-M-DCSK system, and 3DCEC-M-DCSK system, the 3DNCEC-M-DCSK system designed by the present invention introduces a three-dimensional constellation with non-constant envelope on the basis of channel compensation, greatly increasing the minimum Euclidean distance between adjacent symbols, thereby achieving better bit error rate performance. Please refer to Table 2, which shows the comparison table of the minimum Euclidean distance of the constellations between systems under the same overall power.

[0172] Table 2 Comparison of the minimum Euclidean distance of the constellations between 3DNCEC-M-DCSK system and 2DCEC-M-DCSK system, 2DNCEC-M-DCSK system, and 3DCEC-M-DCSK system

[0173]

[0174] Furthermore, please refer to Figure 5 , this example also provides the comparison of the bit error rate performance between the 3DNCEC-M-DCSK system and the 2DCEC-M-DCSK system, 2DNCEC-M-DCSK system, and 3DCEC-M-DCSK system under a multipath Rayleigh fading channel. Among them, the spreading factor ; the modulation order ; the parameter settings of the multipath Rayleigh fading channel are as follows: the number of paths ; having the same power gain ; the path delay , , . From Figure 5 , it can be observed that compared with the 2DCEC-M-DCSK, 2DNCEC-M-DCSK, and 3DCEC-M-DCSK systems, the 3DNCEC-M-DCSK system provided by the present invention greatly increases the minimum Euclidean distance between adjacent symbols, thereby achieving better bit error rate performance.

[0175] In addition, please refer to Figure 6 , this example also provides a comparison of the symbol error rate performance between the 3DNCEC-M-DCSK system and the 3DNCEC-M-DCSK(without CSC) system in a multipath Rayleigh fading channel. Among them, the spreading factor ; modulation order ; the parameter settings of the multipath Rayleigh fading channel are as follows: the number of paths ; with the same power gain ; path delay , , . It can be observed from Figure 6 that the 3DNCEC-M-DCSK system is significantly superior to the 3DNCEC-M-DCSK(without CSC) system in terms of symbol error rate performance. This shows that even though the 3DCEC-M-DCSK system introduces a non-constant envelope three-dimensional constellation, that is, the 3DNCEC-M-DCSK(without CSC) system, without using a cyclic shift converter to estimate the channel power gain and value with the received reference signal to perform channel compensation on the system, the system exhibits poor symbol error rate performance due to channel fading interference, that is, it still fails to fully exhibit better system performance, which further verifies the transmission reliability of the 3DNCEC-M-DCSK system provided by the present invention.

[0176] Therefore, the 3DNCEC-M-DCSK system provided by the present invention can become a low-power, high-rate, and high-reliability wireless communication technology, meeting the requirements of the new generation of wireless communication networks.

[0177] The present invention provides a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram, having the following advantages:

[0178] 1. Compared with the 2DNCEC-M-DCSK system that needs to insert pilot symbols to estimate channel state information, based on a three-dimensional orthogonal basis structure, the present invention introduces a cyclic shift correlator (CSC) to perform channel compensation on the system without the need to insert pilot symbols, effectively using the information carried by the received reference signal itself to estimate the channel power gain and value, thereby performing channel compensation on the received signal and effectively improving the transmission efficiency of the system.

[0179] 2. Aiming at the problem that the minimum Euclidean distance between adjacent mapped symbols is relatively small due to the low utilization rate of the three-dimensional constellation space in the 3DCEC-M-DCSK system, the present invention introduces a non-constant envelope three-dimensional constellation and combines a cyclic shift correlator to perform channel compensation on the system, effectively increasing the minimum Euclidean distance between symbols, thereby improving the transmission reliability of the system.

[0180] Please refer to Figure 7 , the present invention also provides a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram

[0181] A cyclic shift unit 701, configured to perform a cyclic shift operation on a first-level chaotic signal with a length generated by a chaotic generator to obtain a first shifted chaotic signal group; wherein, the first shifted chaotic signal group includes a first chaotic signal, a second chaotic signal, and a third chaotic signal; The mapping unit 702 is configured to map target information bits into three-dimensional constellation symbols with a non-constant envelope through a three-dimensional constellation mapper, and generate an information-bearing signal through information modulation using the three-dimensional constellation symbols with a non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal;

[0182] The transmission unit 703 is configured to generate a transmission signal based on the first chaotic signal and the information-bearing signal, and transmit the transmission signal to a receiver to generate a received signal;

[0183] The receiving and processing unit 704 is configured to, in the receiver, filter the received signal to obtain a received reference signal and a received bearing signal, perform a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group;

[0184] The channel compensation unit 705 is configured to perform a correlation operation on the received bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and perform a channel compensation operation on the correlation quantity to obtain a normalized decision vector;

[0185] The information recovery unit 706 is configured to perform information recovery analysis on the normalized decision vector to estimate the transmitted information bits.

[0186] The present invention also provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the steps of any of the above DCSK communication methods are implemented.

[0187] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above DCSK communication methods are implemented.

[0188] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above DCSK communication methods are implemented.

[0189] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0190] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections between each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0191] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0192] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0193] If the above-mentioned integrated unit is implemented in the form of 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 this 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 for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0194] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements 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 DCSK communication method based on a non-constant envelope three-dimensional constellation diagram, characterized in that: The method comprises: The length of the chaos generator is The first chaotic signal is subjected to a cyclic shift operation to obtain a first shifted chaotic signal group; wherein the first shifted chaotic signal group includes a first chaotic signal, a second chaotic signal and a third chaotic signal; Mapping target information bits into a three-dimensional constellation symbol with a non-constant envelope, and performing information modulation by using the three-dimensional constellation symbol with the non-constant envelope, the first chaotic signal, the second chaotic signal and the third chaotic signal to generate an information-bearing signal; generating a transmission signal based on the first chaotic signal and the information bearing signal, and transmitting the transmission signal to a receiver to generate a reception signal; In the receiver, filtering the received signal to obtain a received reference signal and a received bearer signal, and performing a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group; Performing a correlation operation on the received bearer signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing a channel compensation operation on the correlation quantity to obtain a normalized decision vector; Information recovery analysis is performed on the normalized decision vector to estimate the transmission information bits.

2. The DCSK communication method according to claim 1, characterized in that: The length of the chaos generator is The step of performing a cyclic shift operation on the first-level chaotic signal to obtain a first shifted chaotic signal group comprises: The length of the chaos generator is Performing a cyclic shift operation on the first-level chaotic signal to obtain a second-level chaotic signal; Superimposing the primary chaotic signal and the secondary chaotic signal to obtain a first chaotic signal; The first chaotic signal is subjected to a cyclic shift operation by a cyclic shift transformer to obtain a second chaotic signal and a third chaotic signal.

3. The DCSK communication method according to claim 2, characterized in that: The step of mapping the target information bit into a three-dimensional constellation symbol with a non-constant envelope, and performing information modulation to generate an information-bearing signal by using the three-dimensional constellation symbol with a non-constant envelope, the first chaotic signal, the second chaotic signal and the third chaotic signal comprises: Mapping target information bits into three-dimensional constellation symbols having a non-constant envelope by a three-dimensional constellation mapper; The amplitudes of the three-dimensional constellation symbol with a non-constant envelope on the x-axis, the y-axis and the z-axis are respectively modulated by the first chaotic signal, the second chaotic signal and the third chaotic signal to generate an information-bearing signal.

4. The DCSK communication method according to claim 1, characterized in that: The step of generating a transmission signal based on the first chaotic signal and the information bearing signal, and transmitting the transmission signal to a receiver to generate a receiving signal comprises: Performing a pulse shaping operation on the first chaotic signal and the information-bearing signal to obtain a pulse reference signal and a pulse-bearing signal respectively; Based on a preset carrier frequency, superimposing the pulse reference signal and the pulse bearing signal to obtain a transmission signal; The transmission signal is transmitted to a receiver via a wireless channel to generate a reception signal.

5. The DCSK communication method according to claim 1, characterized in that: The second shifted chaotic signal group includes a received reference signal, a third-level chaotic signal, a fourth chaotic signal, and a fifth chaotic signal; in the receiver, filtering the received signal to obtain a received reference signal and a received bearer signal, and performing a cyclic shift operation on the received reference signal to obtain the second shifted chaotic signal group comprises: In the receiver, the received signal is filtered by a matched filter to obtain a received reference signal and a received bearer signal; The received reference signal is subjected to a cyclic shift transformer with a length of The cyclic shift operation of , obtains the three-level chaotic signal; The received reference signal is subjected to a cyclic shift transformer with a length of and A cyclic shift operation is performed to respectively construct a first reference signal and a second reference signal; The received reference signal, the first reference signal and the second reference signal are Schmidt-orthogonalized to recover a fourth chaotic signal and a fifth chaotic signal.

6. The DCSK communication method according to claim 5, characterized in that: The step of performing a correlation operation on the received bearer signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing a channel compensation operation on the correlation quantity to obtain a normalized decision vector comprises: Generate an initial decision vector by performing correlation operations on the received bearer signal with the received reference signal, the fourth chaotic signal and the fifth chaotic signal respectively; Performing correlation operation on the received reference signal and the three-level chaotic signal to obtain a channel power gain and value; A channel compensation operation is performed on the initial decision vector based on the channel power gain and value to obtain a normalized decision vector.

7. The DCSK communication method according to claim 1, characterized in that: The step of performing information recovery analysis on the normalized decision vector to estimate the transmission information bit includes: Based on a minimum Euclidean distance algorithm, estimating a label of the three-dimensional constellation symbol with a non-constant envelope through the normalized decision vector to obtain an estimated label; A bit recovery operation is performed through the estimation tag to estimate the transmission information bit.

8. A DCSK communication device based on a non-constant envelope three-dimensional constellation diagram, characterized in that: The device comprises: The cyclic shift unit is used to convert the length of the chaotic generator to The first chaotic signal is subjected to a cyclic shift operation to obtain a first shifted chaotic signal group; wherein the first shifted chaotic signal group includes a first chaotic signal, a second chaotic signal and a third chaotic signal; A mapping unit, configured to map the target information bit into a three-dimensional constellation symbol with a non-constant envelope through a three-dimensional constellation mapper, and to generate an information-bearing signal by performing information modulation through the three-dimensional constellation symbol with the non-constant envelope, the first chaotic signal, the second chaotic signal and the third chaotic signal; A transmission unit, configured to generate a transmission signal based on the first chaotic signal and the information bearing signal, and transmit the transmission signal to a receiver to generate a reception signal; A receiving processing unit, configured to filter and process the received signal in a receiver to obtain a received reference signal and a received bearer signal, and perform a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group; A channel compensation unit, used for performing a correlation operation on the received bearer signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing a channel compensation operation on the correlation quantity to obtain a normalized decision vector; The information recovery unit is used to perform information recovery analysis on the normalized decision vector to estimate the transmission information bits.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the DCSK communication method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the DCSK communication method according to any one of claims 1 to 7 are implemented.

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