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

Abstract

The application discloses a DCSK communication method based on a non-constant envelope three-dimensional constellation and related devices, and the method comprises the following steps: obtaining a first shift chaotic signal group by cyclically shifting a first-level chaotic signal, mapping target information bits into three-dimensional constellation symbols with a non-constant envelope; modulating the three-dimensional constellation symbols with a non-constant envelope and the first shift chaotic signal group into information-bearing signals; sending a transmission signal generated by the first chaotic signal and the information-bearing signals to a receiver, obtaining and filtering a received signal, generating a received reference signal and a received bearing signal, obtaining a second shift chaotic signal group by cyclically shifting the received reference signal; obtaining a correlation quantity by correlating the received bearing signal and the second shift chaotic signal group, compensating the correlation quantity to obtain a decision vector and estimating transmission information bits. In the application, a three-dimensional constellation with a non-constant envelope is introduced, and the system is compensated by using a received reference signal, so that the transmission efficiency and reliability are effectively improved.

Description

TECHNICAL FIELD

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

[0002] With the rapid development of information industry, mobile Internet business is growing explosively. Massive business data brings severe challenges to the transmission rate, spectrum efficiency and reliability of the next generation wireless communication network. Therefore, the research of low-power, low-cost, efficient and reliable wireless communication technology is imminent. Chaos theory is an important branch of nonlinear science, which originated from the sensitivity of nonlinear systems to initial conditions. As a cross-disciplinary theory, chaos theory has been widely applied in meteorology, biology, economics, physics and telecommunications. Chaos communication is a scientific theory that applies chaos signals to the field of communication, which mainly utilizes the good characteristics of chaos signals such as determinacy, initial value sensitivity, wide spectrum and noise-like. Due to these inherent characteristics, the chaos communication system has potential advantages in secure communication, anti-interference and anti-multipath fading.

[0003] At present, the research of chaos communication in wireless communication mainly focuses on chaos digital modulation. Differential chaos shift keying (DCSK) technology has become a widely studied non-coherent chaos digital modulation scheme due to its low power consumption and low cost. However, the existing DCSK scheme still has deficiencies in communication performance such as transmission rate and transmission reliability, which is difficult to meet the needs of the new generation of wireless communication network. Therefore, it is urgent to further optimize the DCSK scheme to improve its communication performance. SUMMARY

[0004] The present application provides a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram and related devices, which solves the technical problem that the existing DCSK scheme still has deficiencies in communication performance such as transmission rate and transmission reliability, which is difficult to meet the needs of the new generation of wireless communication network.

[0005] The present application provides a DCSK communication method based on a non-constant envelope three-dimensional constellation diagram, which comprises:

[0006] performing a cyclic shift operation on a first-level chaos signal generated by a chaos generator, the first-level chaos signal having a length of N, to obtain a first group of shifted chaos signals; wherein the first group of shifted chaos signals comprises a first chaos signal, a second chaos signal and a third chaos signal;

[0007] ​mapping target information bits into three-dimensional constellation symbols with non-constant envelope, and generating information-bearing signals by information modulation of the three-dimensional constellation symbols with non-constant envelope, the first chaotic signal, the second chaotic signal and the third chaotic signal;

[0008] generating transmission signals based on the first chaotic signal and the information-bearing signals, and transmitting the transmission signals to a receiver to generate receiving signals;

[0009] in the receiver, filtering the receiving signals to obtain receiving reference signals and receiving bearing signals, performing cyclic shift operation on the receiving reference signals to obtain a second group of shifted chaotic signals;

[0010] performing correlation operation on the receiving bearing signals and the second group of shifted chaotic signals to obtain correlation quantities, and performing channel compensation operation on the correlation quantities to obtain normalized decision vectors;

[0011] performing information recovery analysis on the normalized decision vectors to estimate transmission information bits.

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

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

[0014] superimposing the first chaotic signal and the second chaotic signal to obtain a first chaotic signal;

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

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

[0017] mapping target information bits into three-dimensional constellation symbols with non-constant envelope by a three-dimensional constellation mapper;

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

[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, comprises:

[0020] Pulse shaping the first chaotic signal and the information-bearing signal to obtain a pulse reference signal and a pulse-bearing signal, respectively;

[0021] Superimposing the pulse reference signal and the pulse-bearing signal based on a preset carrier frequency to obtain a transmission signal;

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

[0023] Further, the second shifted chaotic signal group includes a received reference signal, a tertiary 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 a second shifted chaotic signal group, comprises:

[0024] Filtering the received signal in the receiver through a matched filter to obtain a received reference signal and a received-bearing signal;

[0025] Performing a cyclic shift operation on the received reference signal through a cyclic shift converter to obtain a tertiary chaotic signal;

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

[0027] Schmidt orthogonalizing the received reference signal, the first reference signal, and the second reference signal to recover a fourth chaotic signal and a 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, comprises:

[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 tertiary chaotic signal to obtain a channel power gain and a value;

[0031] ​​​Based on the channel power gain and value, a channel compensation operation is performed on the initial decision vector to obtain a normalized decision vector.

[0032] Furthermore, 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, the label of the three-dimensional constellation symbol with non-constant envelope is estimated through the normalized decision vector to obtain the estimated label;

[0034] The transmitted information bits are estimated by performing a bit recovery operation using the estimated tag.

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

[0036] Circular shift unit, used to convert the length generated by the chaos generator into a cyclic shift unit. The first-order 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;

[0037] The mapping unit is used to map target information bits into three-dimensional constellation symbols with non-constant envelopes through a three-dimensional constellation mapper, and to generate information-bearing signals by information modulation through the three-dimensional constellation symbols with non-constant envelopes, the first chaotic signal, the second chaotic signal and the third chaotic signal;

[0038] A transmission unit is configured to generate a transmission signal based on the first chaotic signal and the information-carrying signal, and transmit the transmission signal to a receiver to generate a received signal;

[0039] The receiving processing unit is used in the receiver to filter the received signal to obtain a received reference signal and a received bearer signal, and to perform a cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group.

[0040] The channel compensation unit is used to perform a correlation operation on the received bearer signal and the second shifted chaotic signal group to obtain a correlation quantity, and to perform a channel compensation operation on the correlation quantity to obtain a normalized decision vector.

[0041] The information recovery unit is used to perform information recovery analysis on the normalized decision vector and estimate the transmitted information bits.

[0042] The present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the DCSK communication methods described above.

[0043] The application further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the DCSK communication method according to any one of the above.

[0044] From the above technical solutions, the application has the following advantages:

[0045] The application provides a DCSK communication method based on a non-constant envelope three-dimensional constellation and related devices, wherein the method comprises the following steps: performing a cyclic shift operation on a first-level chaotic signal generated by a chaotic generator and having a length of N, to obtain a first group of shifted chaotic signals; wherein the first group of shifted chaotic signals comprises 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 using the three-dimensional constellation symbols with the 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 group of shifted chaotic signals; performing correlation operation on the received bearing signal and the second group of shifted chaotic signals to obtain a correlation quantity, and performing 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 transmission information bits.

[0046] In the application, a three-dimensional constellation with a non-constant envelope is introduced to effectively improve the minimum Euclidean distance between symbols, and a cyclic shift converter and a correlator are designed to estimate the channel power gain and value by using the information carried by the received reference signal itself to 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 new-generation wireless communication networks. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the application or the technical solutions that can be achieved in combination with the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0048] Figure 1A step flow chart of a DCSK communication method based on a non-constant envelope three-dimensional constellation provided by an embodiment of the present application is provided.

[0049] Figure 2 A structure diagram of a transmitter and a receiver of a DCSK system based on a non-constant envelope three-dimensional constellation provided by an embodiment of the present application is provided.

[0050] Figure 3 A structure diagram of a non-constant envelope three-dimensional constellation provided by an embodiment of the present application is provided.

[0051] Figure 4 A data processing diagram of a cyclic shift changer and a correlator provided by an embodiment of the present application is provided.

[0052] Figure 5 A bit error rate performance comparison diagram between a 3D NEC-M-DCSK system and a 2D NEC-M-DCSK system, a 2D NEC-M-DCSK system and a 3D NEC-M-DCSK system provided by an embodiment of the present application is provided.

[0053] Figure 6 A symbol error rate performance comparison diagram between a 3D NEC-M-DCSK system and a 3D NEC-M-DCSK(without CSC) system provided by an embodiment of the present application is provided.

[0054] Figure 7 A structure diagram of a DCSK communication device based on a non-constant envelope three-dimensional constellation provided by an embodiment of the present application is provided.

[0055] Figure 8 A structure diagram of a transmitter and a receiver of a typical DCSK system provided by an embodiment of the present application in combination with prior art is provided.

[0056] Figure 9 A structure diagram of a transmitter and a receiver of a 2D NEC-M-DCSK system provided by an embodiment of the present application in combination with prior art is provided.

[0057] Figure 10 A constellation structure and a decision region diagram of a 2D NEC-M-DCSK system provided by an embodiment of the present application in combination with prior art is provided.

[0058] Figure 11 A structure diagram of a transmitter and a receiver of a 2D NEC-M-DCSK system provided by an embodiment of the present application in combination with prior art is provided.

[0059] Figure 12 A constellation structure and a decision region diagram of a 2D NEC-M-DCSK system provided by an embodiment of the present application in combination with prior art is provided.

[0060] Figure 13 The structure diagram of a transmitter and a receiver of a 3DCEC-M-DCSK system provided by the embodiment of the present application in combination with the prior art is shown in the following figure:

[0061] Figure 14 The constellation structure diagram of a 3DCEC-M-DCSK system provided by the embodiment of the present application in combination with the prior art is shown in the following figure. DETAILED DESCRIPTION

[0062] The embodiment of the present application provides a DCSK communication method based on a non-constant envelope three-dimensional constellation and related devices, and aims at 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 a new generation of wireless communication network.

[0063] In order to make the technical scheme of the present application more apparent and easy to understand, the technical scheme in the embodiment of the present application will be described clearly and completely below in combination with the accompanying drawings in the embodiment of the present application. Obviously, the following described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

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

[0065] 1. Typical DCSK system

[0066] Please refer to Figure 8 , the transmitter first generates a chaotic signal with a length of by using a chaotic generator , wherein the spreading factor of the DCSK system is defined as . In the typical DCSK system, the symbol duration of each frame of transmission symbols is equally divided into two symbol periods, the first symbol period transmits the chaotic signal , and the second symbol period transmits the chaotic signal carrying information bits. Specifically, , represents the transmitted information bits, wherein . If , the information-carrying signal transmits a copy signal of , otherwise the information-carrying signal transmits a negative polarity signal of .

[0067] wherein the - transmission signal of the typical DCSK system is represented as:

[0068] (1)

[0069] The transmission signal is processed by delay and modulation to obtain a transmit signal, and the transmit signal is transmitted through a wireless channel to reach a receiver. The signal received by the receiver can be expressed as:

[0070] (2)

[0071] wherein, represents a convolution operation; and are respectively - channel coefficients and delays of paths; is an additive white Gaussian noise with a mean of zero and a variance of .

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

[0073] (3)

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

[0075] (4)

[0076] The typical DCSK system divides one symbol duration into two periods, and the former period is used to transmit a reference signal, and the latter period is used to transmit a signal carrying information. However, this operation makes half of the time and energy used to transmit the reference signal, so that the energy efficiency and spectral efficiency of the system are at a low level.

[0077] 2、2DCEC-M-DCSK system

[0078] Compared with the typical DCSK system, the two-dimensional constant-envelope constellation-assisted M-DCSK (2DCEC-M-DCSK) system greatly improves the data transmission rate and transmission reliability. Among them, the 2DCEC-M-DCSK system can transmit bits in one symbol period, thereby improving the data transmission rate. Please refer to Figure 9The 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, M is the modulation order; and represent the real part and the imaginary part of the two-dimensional constellation symbol, respectively. Please refer to Figure 10 , Figure 10 exhibits one of the constellation structures of the 2DCEC-M-DCSK system in the case of .

[0080] Then the chaotic generator generates a chaotic reference signal , which is converted into another orthogonal signal by a Hilbert transformer, thereby generating two orthogonal chaotic signals. In order to transmit two-dimensional coordinate information, the signals and carry the real part and the imaginary part of the upper constellation symbol, respectively, so as to obtain the information-bearing signal, i.e. . Similarly, in the 2DCEC-M-DCSK system, the reference signal is sent in the first half of the symbol period, and the information-bearing signal is sent in the second half of the symbol period.

[0081] wherein the transmission signal can be expressed as:

[0082] (1)

[0083] At the receiving end, the noise-polluted reference signal is Hilbert-transformed to obtain the signal , and the signals and are respectively correlated with the noise-polluted information-bearing signal to obtain the decision vector

[0084] (2)

[0085] The obtained decision vector and the decision region shown in Figure 10 are used to determine the estimated value of the bit information.

[0086] For the 2DCEC-M-DCSK system, the transmission efficiency of the typical DCSK system is indeed improved. However, the 2DCEC-M-DCSK system limits the performance of the system due to the small minimum Euclidean distance between adjacent symbols.

[0087] 3. 2D NCEC-M-DCSK system

[0088] Unlike the 2DCEC-M-DCSK system, the Two-dimensional non-constant-envelope constellation-assisted M-DCSK (2DNCEC-M-DCSK) system introduces a non-constant-envelope two-dimensional constellation, and the system also needs to insert pilot symbols for channel estimation. Since the channel is slow fading, it is reasonable that the channel parameters remain unchanged within some symbol duration. The following briefly introduces the difference 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 that the transmitted pilot symbol is , due to the symmetry of the decision variable, analyzing the decision variable of one coordinate value can obtain:

[0090] (7)

[0091] Therefore, if a least square (LS) estimator is used, the channel parameter estimation is:

[0092] (8)

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

[0094] For the 2DNCEC-M-DCSK system, it improves the minimum Euclidean distance between adjacent symbols to some 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, thereby reducing the transmission efficiency of the system.

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

[0096] Because the minimum Euclidean distance of two-dimensional constellation is small, which leads to a high lower bound of bit error rate (BER) of the system, a three-dimensional constant-envelope constellation-assisted M-ary differential chaos shift keying (3DCEC-M-DCSK) system is proposed.

[0097] Please refer to Figure 13 and Figure 14 , wherein the figure (14) corresponds to the constant envelope three-dimensional constellations of (a), (b) and (c) respectively corresponding to the modulation order , and . Specifically, the transmitter of the 3DCEC-M-DCSK system first generates a chaotic signal through a chaotic generator, which is expressed as:

[0098] .(9)

[0099] The chaotic signal can be obtained through a cyclic shift operation, and can be specifically expressed as: (10)

[0100] (11)

[0101] (11)

[0102] wherein and are the shift numbers of the cyclic shift operation for obtaining the chaotic signals and . Because of the good cross-correlation between the chaotic signals, the chaotic signals , and can be approximately orthogonal to each other (i.e. , and ).

[0103] Then, the chaotic signals , and are subjected to Schmidt orthogonalization to ensure that the chaotic signals satisfy strict orthogonality with each other. Then, the information bits are mapped to a three-dimensional constellation symbol , wherein is the label of the three-dimensional constellation symbol, M is the modulation order, and satisfies . , and​​ The values of axis, axis and axis, which are carried by chaotic signals , and respectively.

[0104] Therefore, the information-carrying signal of the 3DCEC-M-DCSK system can be expressed as Then, the reference signal and the information-carrying signal after pulse shaping are expressed as and respectively, where is the unit power pulse shaping function; denotes 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 is passed through a matched filter to obtain the noise-polluted reference signal and the information-carrying signal . Then, the reference signal is subjected to a cyclic shift operation with length and to construct the reference signals and respectively. To estimate the transmitted information bits, by performing a correlation operation between the received information-carrying signal and 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 For the modulo operation.

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

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

[0114] The present application aims at the problem of insufficient communication performance of the DCSK system that can be realized in combination with the prior art, and proposes a 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 application provides a DCSK communication method based on a non-constant-envelope three-dimensional constellation, the method comprising:

[0116] Step 101, performing a cyclic shift operation on a primary chaotic signal generated by a chaotic generator and having a length of to obtain a first group of shifted chaotic signals.

[0117] Further, step 101 comprises:

[0118] First, performing a cyclic shift operation on a primary chaotic signal generated by a chaotic generator and having a length of to obtain a secondary chaotic signal .

[0119] Wherein, the primary chaotic signal is expressed as:

[0120] (14)

[0121] The secondary chaotic signal is expressed as:

[0122] (15)

[0123] Wherein, The condition of being divisible by 2 needs to be met.

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

[0125] (16)

[0126] Then, the first chaotic signal is subjected to cyclic shift operation with length and to obtain the second chaotic signal and the third chaotic signal . Wherein, is a floor operation.

[0127] It should be noted that due to the good cross-correlation characteristics of the chaotic signal, the chaotic signals , and can be approximately orthogonal to each other (that is, , and ). Therefore, the chaotic signals , and can be subjected to Schmidt orthogonalization to ensure that the chaotic signals meet the strict orthogonality. The energy of the obtained chaotic signals is normalized to 1, that is: .

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

[0129] Step 102, map the target information bits into three-dimensional constellation symbols with non-constant envelope, and generate information bearing signals by information modulation through 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 by a three-dimensional constellation mapper, which can effectively improve the minimum Euclidean distance between symbols (that is, the distance between adjacent constellation points of information symbol mapping); wherein, is the label of the three-dimensional constellation symbol, is the modulation order; 、 and respectively represent amplitude of the x-axis, amplitude of the y-axis and amplitude of the z-axis, and under the characteristic of non-constant envelope, the amplitude of the three-dimensional constellation symbol will change with the transmission process.

[0131] Then, the amplitudes of the three-dimensional constellation symbol with non-constant envelope on the x-axis, the y-axis and the z-axis are respectively information-modulated by the first chaotic signal, the second chaotic signal and the third chaotic signal to generate information-carrying signals .

[0132] Step 103, generating a transmission signal based on the first chaotic signal and the information-carrying signal, and transmitting the transmission signal to the receiver to generate a received signal.

[0133] In this step, first, the first chaotic signal and the information-carrying signal are subjected to pulse shaping operation to obtain pulse reference signals and pulse-carrying signals respectively; wherein represents a unit power pulse shaping function, represents a chip time.

[0134] Then, based on a preset carrier frequency, the pulse reference signal and the pulse-carrying signal are superimposed to obtain a transmission signal; wherein the transmission signal is represented as:

[0135] (17)

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

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

[0138] Step 104, in the receiver, filtering the received signal to obtain a received reference signal and a received-carrying signal, and performing a cyclic shift operation on the received reference signal to obtain a second group of shifted chaotic signals.

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

[0140] Step 104 specifically includes:

[0141] Sub-step 1041, in the receiver, filtering the received signal by a matched filter to obtain a noise-contaminated received reference signal and receiving the signal carrying the information

[0142] Sub-step 1042, performing a cyclic shift operation on the received reference signal by a cyclic shift transformer to obtain a third chaotic signal with a length of ;

[0143] It should be noted that the channel compensation needs to obtain the channel power gain and, rather than the fading coefficient of each channel, which is different from the traditional channel estimation in a coherent communication system. In particular, the present application can estimate the channel power and value by effectively utilizing the information carried by the received reference signal itself without inserting any additional pilot symbols. The specific operation is as follows: performing a cyclic shift operation on the received reference signal with a length of 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 ; then, performing a cyclic shift operation on the received reference signal with a length of to obtain a third chaotic signal , wherein the third chaotic signal is superimposed by the first chaotic signal and different noise obtained after the shift. It should be particularly noted that the first chaotic signal remains unchanged in length after performing the cyclic shift operation with a length of , as shown below:

[0145] (18)

[0146] wherein represents performing a cyclic shift operation on with a length of .

[0147] Sub-step 1043, performing a cyclic shift operation on the received reference signal by a cyclic shift transformer to obtain a first reference signal and a second reference signal with lengths of and , respectively;

[0148] Sub-step 1044, Schmitt orthogonalization of the received reference signal First reference signal Second reference signal The fourth chaotic signal was recovered. and the fifth chaotic signal .

[0149] Step 105: Obtain the correlation quantity by performing correlation operations on the received bearer signal and the second shifted chaotic signal group, and obtain the normalized decision vector by performing channel compensation operations on the correlation quantity.

[0150] This step specifically includes:

[0151] Sub-step 1051 involves receiving the bearer signal and the received reference signal respectively. Fourth chaotic signal and the fifth chaotic signal Perform relevant operations to generate an initial decision vector;

[0152] It should be noted that, in order to estimate the transmitted information bits, it is necessary to obtain the received bearer signal. respectively with chaotic signals , and By performing the relevant operations, the initial decision vector can be obtained. ,in, ; ; .

[0153] Sub-step 1052, by receiving a reference signal and Level 3 chaotic signals Perform relevant operations to obtain the channel power gain and value;

[0154] In this sub-step, by... and After performing the relevant operations, the variables can be obtained. ,Right now,

[0155] (19)

[0156] Furthermore, variables It can be approximated as:

[0157] (20)

[0158] In the formula, Indicates the first Fading coefficient under each path This represents the Gaussian white noise of the received reference signal. Then by cyclic shift operation.

[0159] By analyzing, the variable as the estimated channel power gain and value, i.e. .

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

[0161] Step 106, performing information recovery analysis on the normalized decision vector to estimate the transmission information bits.

[0162] It is worth noting that two different non-constant envelope three-dimensional constellations are used as examples in this embodiment: a cross-lattice constellation with a modulation order of 32 as shown in Figure 3 (a) and a 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 non-constant envelope constellation introduced achieves a larger minimum Euclidean distance under 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] In the formula: is a modulo operation.

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

[0167] The 3DNCEC-M-DCSK system provided by the present application introduces a non-constant envelope three-dimensional constellation, and designs a cyclic shift shifter and a correlator to perform channel compensation on the system, thereby effectively improving the transmission efficiency and transmission reliability of the system. The performance of the 3DNCEC-M-DCSK system is further analyzed below in combination with Figure 5 and Figure 6 .

[0168] 1) For transmission efficiency: assuming that in the 2D NEC-M-DCSK system, a pilot symbol is inserted at the end of every G information-bearing signal. Then, compared with the 2D NEC-M-DCSK system, the 3D NEC-M-DCSK system of the present application does not need the assistance of inserting a pilot symbol, thereby realizing higher data transmission rate and spectral efficiency, and the specific transmission efficiency comparison data are shown in Table 1.

[0169] Table 1 Transmission efficiency and spectral efficiency comparison of 3D NEC-M-DCSK system and 2D NEC-M-DCSK system

[0170]

[0171] 2) For transmission reliability: compared with the 2D CEC-M-DCSK system, the 2D NEC-M-DCSK system and the 3D CEC-M-DCSK system, the 3D NEC-M-DCSK system designed in the present application introduces a non-constant envelope three-dimensional constellation under the basis of channel compensation, greatly increases the minimum Euclidean distance between adjacent symbols, thereby realizing better bit error rate performance. Please refer to Table 2, which shows the constellation minimum Euclidean distance comparison table between the systems under the condition of the same overall power.

[0172] Table 2 Minimum Euclidean distance comparison of constellation between 3D NEC-M-DCSK system and 2D CEC-M-DCSK system, 2D NEC-M-DCSK system and 3D CEC-M-DCSK system

[0173]

[0174] Further, please refer to Figure 5 , the present example also provides the bit error rate performance comparison between the 3D NEC-M-DCSK system and the 2D CEC-M-DCSK system, the 2D NEC-M-DCSK system and the 3D CEC-M-DCSK system under the multipath Rayleigh fading channel. Among them, the spreading factor ; the modulation order ; the parameter setting of the multipath Rayleigh fading channel is as follows: the number of paths ; has the same power gain ; path delay , , . It can be observed from Figure 5 that compared with the 2D CEC-M-DCSK, the 2D NEC-M-DCSK and the 3D CEC-M-DCSK system, the 3D NEC-M-DCSK system provided in the present application greatly increases the minimum Euclidean distance between adjacent symbols, thereby realizing better bit error rate performance.

[0175] In addition, please refer to Figure 6 , the example also provides the comparison of the symbol error rate performance between the 3D NCEC-M-DCSK system and the 3D NCEC-M-DCSK(without CSC) system under the multipath Rayleigh fading channel. Wherein, the spreading factor ; the modulation order ; the parameter setting of the multipath Rayleigh fading channel is as follows: the path number ; has the same power gain ; the path delay , , It can be observed from Figure 6 that the 3D NCEC-M-DCSK system is significantly better than the 3D NCEC-M-DCSK(without CSC) system in the symbol error rate performance. This shows that even if the 3D CECC-M-DCSK system introduces a non-constant envelope three-dimensional constellation, i.e. 3D NCEC-M-DCSK(without CSC) system, without the channel compensation of the system by the cyclic shift correlator using the received reference signal to estimate the channel power gain and value, the system will show poor symbol error rate performance due to the interference of the channel fading, i.e. still unable to fully show better system performance, which further verifies the transmission reliability of the 3D NCEC-M-DCSK system provided by the application.

[0176] Therefore, the 3D NCEC-M-DCSK system provided by the application can become a kind of low-power, high-speed and high-reliability wireless communication technology, which can meet the demand of new generation wireless communication network.

[0177] The application provides a DCSK communication method based on non-constant envelope three-dimensional constellation, which has the following advantages:

[0178] 1. Compared with the 2D NCEC-M-DCSK system which needs to insert pilot symbols to estimate channel state information, the application based on three-dimensional orthogonal basis structure introduces a cyclic shift correlator (CSC) to compensate the system without inserting pilot symbols, effectively utilizes the information carried by the received reference signal to estimate the channel power gain and value, thereby compensating the received signal, and effectively improves the transmission efficiency of the system.

[0179] 2. In view of the problem of small minimum Euclidean distance between adjacent mapped symbols caused by low utilization of three-dimensional constellation space of the 3DCEC-M-DCSK system, the application introduces a non-constant envelope three-dimensional constellation, and combines a cyclic shift correlator to perform channel compensation on the system, effectively improving the minimum Euclidean distance between symbols, thereby improving the transmission reliability of the system.

[0180] Please refer to Figure 7 The application also provides a DCSK communication method based on a non-constant envelope three-dimensional constellation

[0181] The cyclic shift unit 701 is configured to perform a cyclic shift operation on a chaotic generator generated first chaotic signal with a length of to obtain a first shift chaotic signal group; wherein the first shift chaotic signal group comprises a first chaotic signal, a second chaotic signal and a third chaotic signal.

[0182] The mapping unit 702 is configured to map target information bits into a three-dimensional constellation symbol with a non-constant envelope through a three-dimensional constellation mapper, and generate an information carrying signal through information modulation of the three-dimensional constellation symbol with a non-constant envelope, the first chaotic signal, the second chaotic signal and the third chaotic signal.

[0183] The transmission unit 703 is configured to generate a transmission signal based on the first chaotic signal and the information carrying signal, and transmit the transmission signal to a receiver to generate a received signal.

[0184] The receiving processing unit 704 is configured to filter the received signal to obtain a received reference signal and a received carrying signal in the receiver, and perform a cyclic shift operation on the received reference signal to obtain a second shift chaotic signal group.

[0185] The channel compensation unit 705 is configured to perform a correlation operation on the received carrying signal and the second shift chaotic signal group to obtain a correlation quantity, and perform a channel compensation operation on the correlation quantity to obtain a normalized decision vector.

[0186] The information recovery unit 706 is configured to perform information recovery analysis on the normalized decision vector to estimate the transmission information bits.

[0187] The application also provides a computer device comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps of the DCSK communication method of any one of the above when executing the computer program.

[0188] The application also provides a computer readable storage medium having a computer program stored thereon, and the computer program is executed by a processor to implement the steps of the DCSK communication method of any one of the above.

[0189] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0190] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic, and the division of the units is merely a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0191] The units described as separated components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments of the present application.

[0192] In addition, each functional unit in the embodiments of the present application can be integrated in a processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be implemented in the form of hardware, or in the form of a software functional unit.

[0193] When the 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 such an understanding, the technical solutions of the present application essentially, or the part that makes a contribution to the prior art, or all or a part of the technical solutions can be embodied in the form of a software product. The 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 the embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0194] The above-described embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalent replacements; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A DCSK communication method based on non-constant envelope three-dimensional constellation, characterized in that, The method comprises: The chaotic generator generates a first chaotic signal with a length of A cyclic shift operation is performed on the first chaotic signal to obtain a first group of shifted chaotic signals; the first group of shifted chaotic signals includes a first chaotic signal, a second chaotic signal, and a third chaotic signal. mapping target information bits into three-dimensional constellation symbols with non-constant envelope, and performing information modulation on the three-dimensional constellation symbols with 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 received signal; in the receiver, filtering the received signal to obtain a received reference signal and a received bearing signal, performing cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group; performing correlation operation on the received bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing 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 transmission information bits; The second shifted chaotic signal group comprises a received reference signal, a third-level 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 cyclic shift operation on the received reference signal to obtain a second shifted chaotic signal group comprises: in the receiver, filtering the received signal by a matched filter to obtain a received reference signal and a received bearing signal; The received reference signal is subjected to a cyclic shift operation with a length of to obtain a three-stage chaotic signal. The received reference signal is subjected to a cyclic shift operation with a length of and to construct a first reference signal and a second reference signal, respectively. performing 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; The step of performing correlation operation on the received bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and performing channel compensation operation on the correlation quantity to obtain a normalized decision vector comprises: performing correlation operation on the received bearing signal, the received reference signal, the fourth chaotic signal and the fifth chaotic signal respectively to generate an initial decision vector; performing correlation operation on the received reference signal and the third-level chaotic signal to obtain a channel power gain value; performing channel compensation operation on the initial decision vector based on the channel power gain value to obtain a normalized decision vector.

2. The DCSK communication method according to claim 1, characterized in that, The step of performing a cyclic shift operation on the primary chaotic signal generated by the chaotic generator with a length of includes the following steps: The chaotic generator generates a first chaotic signal with a length of A cyclic shift operation is performed on the first chaotic signal to obtain a second chaotic signal. superimposing the first-level chaotic signal and the second-level chaotic signal to obtain a first chaotic signal; performing cyclic shift operation on the first chaotic signal by a cyclic shift converter 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 target information bits into three-dimensional constellation symbols with non-constant envelope, and performing information modulation on the three-dimensional constellation symbols with non-constant envelope, the first chaotic signal, the second chaotic signal and the third chaotic signal to generate an information-bearing signal comprises: mapping target information bits into three-dimensional constellation symbols with non-constant envelope by a three-dimensional constellation mapper; modulating the amplitudes of the three-dimensional constellation symbols with non-constant envelope on 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.

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: Pulse shaping operations are performed on the first chaotic signal and the information-bearing signal to obtain a pulse reference signal and a pulse-bearing signal, respectively; The pulse reference signal and the pulse-bearing signal are superimposed based on a preset carrier frequency to obtain a transmission signal; The transmission signal is transmitted to a receiver through a wireless channel to generate a receiving signal.

5. 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 transmission information bits comprises: Based on a minimum Euclidean distance algorithm, a label of the three-dimensional constellation symbol with a non-constant envelope is estimated from the normalized decision vector to obtain an estimated label; Bit recovery operations are performed on the estimated label to estimate transmission information bits.

6. A DCSK communication apparatus based on non-constant envelope three-dimensional constellation, characterized in that, The apparatus comprises: A cyclic shift unit is configured to cyclically shift a chaotic signal of a length of generated by the chaotic generator to obtain a first group of shifted chaotic signals, wherein the first group of shifted chaotic signals includes a first chaotic signal, a second chaotic signal, and a third chaotic signal. A mapping unit is configured to map target information bits into a three-dimensional constellation symbol with a non-constant envelope through a three-dimensional constellation mapper, and perform information modulation on the three-dimensional constellation symbol with a non-constant envelope, the first chaotic signal, the second chaotic signal, and the third chaotic signal to generate an information-bearing signal; A transmission unit 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 receiving signal; A receiving processing unit is configured to perform filter processing on the receiving signal in the receiver to obtain a receiving reference signal and a receiving-bearing signal, and perform cyclic shift operations on the receiving reference signal to obtain a second shifted chaotic signal group; A channel compensation unit is configured to perform correlation operations on the receiving-bearing signal and the second shifted chaotic signal group to obtain a correlation quantity, and perform channel compensation operations on the correlation quantity to obtain a normalized decision vector; An information recovery unit is configured to perform information recovery analysis on the normalized decision vector to estimate transmission information bits. The receiving processing unit is specifically configured to: perform filter processing on the receiving signal in the receiver through a matched filter to obtain a receiving reference signal and a receiving-bearing signal; The received reference signal is subjected to a cyclic shift operation with a length of to obtain a three-stage chaotic signal. The received reference signal is subjected to a cyclic shift operation with a length of and to construct a first reference signal and a second reference signal, respectively. perform Schmidt orthogonalization on the receiving reference signal, the first reference signal, and the second reference signal to recover a fourth chaotic signal and a fifth chaotic signal; The channel compensation unit is specifically configured to: perform correlation operations on the receiving-bearing signal, the receiving reference signal, the fourth chaotic signal, and the fifth chaotic signal to generate an initial decision vector; perform correlation operations on the receiving reference signal and the three-level chaotic signal to obtain a channel power gain and value; perform channel compensation operations on the initial decision vector based on the channel power gain and value to obtain a normalized decision vector. 7.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-6 when the computer program is executed by the processor. The processor executes the computer program to implement the steps of the DCSK communication method according to any one of claims 1-5.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the DCSK communication method according to any one of claims 1-5.

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