Signal transmission method based on improved Link-16 data link

Abstract

The embodiment of the invention discloses a signal transmission method based on an improved Link-16 data link, and relates to the technical field of wireless communication, and the method comprises the steps: obtaining a to-be-coded signal and an initial parameter of a signal transmitting end; constructing a high-order check matrix based on the initial parameter, and encoding to obtain an encoded signal; determining a selected UST signal in combination with the initial parameter, and calculating to obtain a synchronization sequence corresponding to the UST signal; and performing UST modulation in combination with the synchronization sequence to obtain a modulated signal, and transmitting the modulated signal through a signal transmitting end. According to the method, the coded signal is obtained through high-order check matrix coding, a higher coding gain can be obtained based on high-order LDPC coding, and a synchronization sequence with strong autocorrelation and weak cross correlation can be obtained by selecting the UST signal through unitary space-time modulation, so that on the premise of meeting the requirement of data segment demodulation capability, the characteristics of the synchronization signal can be hidden, and the synchronization gain can be improved. And the synchronous section is not easy to reconnaissance and identify.

Description

Technical Field

[0001] This application relates to the field of wireless communication technologies, and in particular, to a signal transmission method based on an improved Link-16 data link. Background Art

[0002] The Link-16 data link is one of the most widely used tactical data links currently. In terms of channel coding, the Link-16 data link adopts a 32-order (31,15) RS code, which has strong anti-interference ability. In terms of modulation, the Link-16 data link adopts a non-coherent MSK cascaded CCSK (Cyclic Code Shift Keying) soft spread spectrum system, which has a high spread spectrum gain.

[0003] Due to being developed earlier, the related technologies can no longer meet the current requirements. Among them, the RS (Reed-Solomon) code adopted by the Link-16 data link mainly uses hard decision decoding, and the coding gain is relatively insufficient. While using soft information decoding greatly increases the decoding complexity, resulting in low practical value of this coding method; the signal characteristics corresponding to the modulation method of MSK cascaded CCSK adopted by the Link-16 data link are too obvious and are easily discovered by malicious third parties other than the receiving party. Moreover, this coding method cannot be compatible with space-time coding technology and has poor anti-multipath ability. Summary of the Invention

[0004] Embodiments of this application provide a signal transmission method, device, equipment, and storage medium based on an improved Link-16 data link to solve the defects that the LINK16 data link has insufficient coding gain and poor anti-multipath ability of the modulation method signal in the related technologies. The technical solutions are as follows:

[0005] In a first aspect, embodiments of this application provide a signal transmission method based on an improved Link-16 data link, which is characterized in that it is applied to a signal transmitting end, and the method includes:

[0006] Obtain a signal to be encoded and initial parameters of the signal transmitting end;

[0007] Construct a high-order parity-check matrix based on the initial parameters, and encode the signal to be encoded through the high-order parity-check matrix to obtain an encoded signal;

[0008] Randomly generate multiple UST vectors based on the initial parameters, calculate the signal metric values corresponding to the UST vectors respectively based on each UST vector and multiple unitary matrices corresponding to the encoded signal, and determine the selected UST signal based on the numerical values of the signal metric values;

[0009] Randomly generate a plurality of baseband symbol vectors based on the UST signal and the initial parameters, calculate the signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine the selected baseband symbol vector based on the values of the signal secondary peak metric values, and obtain the synchronization sequence corresponding to the UST signal;

[0010] Perform UST modulation in combination with the synchronization sequence to obtain a modulated signal, and transmit the modulated signal through the signal transmitter.

[0011] In an alternative scheme of the first aspect, the initial parameters include the total number of transmitting antennas of the signal transmitter, the data rate, the channel coherence time, the order of the signal, the number of rows of the parity-check matrix, the number of columns of the parity-check matrix, and the set of unitary matrices corresponding to the signal to be encoded.

[0012] In an alternative scheme of the first aspect, the construction of the high-order parity-check matrix based on the initial parameters includes:

[0013] Randomly generate a first parity-check matrix based on the PEG algorithm, select random integers uniformly distributed in a first preset range as the elements in the second parity-check matrix, generate the second parity-check matrix, and construct a high-order parity-check matrix by combining the first parity-check matrix and the second parity-check matrix;

[0014] Calculate the parity-check matrix metric value corresponding to the high-order parity-check matrix. If the parity-check matrix metric value is less than the parity-check matrix metric value threshold, or the number of times of calculating the parity-check matrix metric value is greater than the first preset iteration number, output the parity-check matrix metric value and the corresponding high-order parity-check matrix; otherwise, go to the step of randomly generating the first parity-check matrix based on the PEG algorithm;

[0015] Wherein, the number of rows of the first parity-check matrix and the second parity-check matrix is the number of rows of the parity-check matrix, the number of columns of the first parity-check matrix and the second parity-check matrix is the number of columns of the parity-check matrix, and the lower limit of the first preset range is greater than or equal to 1 and the upper limit is less than or equal to the order of the signal minus 1.

[0016] In an alternative scheme of the first aspect, the calculation of the parity-check matrix metric value corresponding to the high-order parity-check matrix includes:

[0017] Randomly generate a symbol sequence with the length of the symbols participating in the encoding, and each element in the symbol sequence is an arbitrary field element in the Galois field;

[0018] Perform high-order LDPC encoding on the symbol sequence based on the high-order parity-check matrix to obtain a codeword sequence with the length of the number of columns of the parity-check matrix;

[0019] Perform USTM mapping on the codeword sequence to obtain a first UST signal unitary matrix sequence with the number of columns of the parity-check matrix from the set of unitary matrices;

[0020] Calculate the check matrix metric value corresponding to the high-order check matrix based on the first UST signal unitary matrix sequence.

[0021] In an alternative scheme of the first aspect, the method for randomly generating a plurality of UST vectors based on the initial parameters, calculating the signal metric values corresponding to each UST vector respectively based on each UST vector and a plurality of unitary matrices corresponding to the encoded signal, determining the selected UST signal based on the numerical value of the signal metric value, and determining the selected baseband symbol vector based on the numerical value of the signal sub-peak metric value to obtain the synchronization sequence corresponding to the UST signal includes:

[0022] Select random integers uniformly distributed in a second preset range as elements in the UST vector to generate the UST vector, map the UST vector to a complex vector, and construct a diagonal matrix based on the complex vector;

[0023] Calculate the unitary matrix corresponding to each constellation point respectively based on the diagonal matrix and the initial unitary matrix corresponding to symbol 0 in the unitary matrix set, and calculate the set of signal metric values of all constellation points based on the unitary matrix corresponding to each constellation point;

[0024] Output the maximum value in the set of signal metric values as the signal metric value corresponding to the UST vector;

[0025] If the signal metric value corresponding to the UST vector is less than the signal metric value threshold, or the number of times of calculating the signal metric value is greater than the second preset iteration number, output the UST vector and the corresponding signal metric value to obtain the UST signal; otherwise, go to the step of selecting random integers uniformly distributed in the second preset range as elements in the UST vector;

[0026] Wherein, the length of the UST vector is equal to the number of symbol periods, the lower limit of the second preset range is greater than or equal to 0, and the upper limit is less than or equal to the order of the signal minus 1.

[0027] In an alternative scheme of the first aspect, the method for randomly generating a plurality of baseband symbol vectors based on the UST signal and the initial parameters, calculating the signal sub-peak metric value corresponding to each baseband symbol vector respectively, and determining the selected baseband symbol vector based on the numerical value of the signal sub-peak metric value to obtain the synchronization sequence corresponding to the UST signal includes:

[0028] Select random integers uniformly distributed in the second preset range as elements in the baseband symbol vector to generate the baseband symbol vector;

[0029] Perform USTM mapping on the baseband symbol vector, and select the second UST signal unitary matrix sequence with the number of elements in the baseband symbol vector from the unitary matrix set;

[0030] Convert the second UST signal unitary matrix sequence into a two-dimensional matrix;

[0031] Concatenate a matrix of all zeros in front of and behind the two-dimensional matrix to obtain a concatenated matrix;

[0032] Calculate the signal secondary peak metric value corresponding to the baseband symbol vector based on the concatenated matrix and the two-dimensional matrix;

[0033] If the signal secondary peak metric value is less than the signal secondary peak metric value threshold, or the number of times the signal secondary peak metric value is calculated is greater than the third preset iteration number threshold, output the corresponding baseband symbol vector to obtain the synchronization sequence corresponding to the selected UST signal; otherwise, go to the step of selecting random integers uniformly distributed in the second preset range as the elements in the baseband symbol vector.

[0034] In an alternative solution of the first aspect, the calculating the signal secondary peak metric value corresponding to the baseband symbol vector based on the concatenated matrix and the two-dimensional matrix includes:

[0035] Take the k-th row to the (k + K - 1)-th row in the concatenated matrix to obtain a temporary matrix X Tmp ;

[0036] Calculate all metric values based on each temporary matrix and the two-dimensional matrix to form a signal secondary peak metric value set;

[0037] Take the maximum value in the signal secondary peak metric value set to obtain the signal secondary peak metric value corresponding to the baseband symbol vector;

[0038] where K is the number of elements in the baseband symbol vector, k represents the k-th row in the concatenated matrix, and k is an integer greater than or equal to 0 and less than or equal to K - 2.

[0039] In a second aspect, an embodiment of the present application further provides a signal transmission device based on an improved Link-16 data link, including:

[0040] A data acquisition module, configured to acquire a signal to be encoded and initial parameters of the signal transmitter;

[0041] An encoding module, configured to construct a high-order parity-check matrix based on the initial parameters, and encode the signal to be encoded through the high-order parity-check matrix to obtain an encoded signal;

[0042] A modulation module, configured to randomly generate a plurality of UST vectors based on the initial parameters, calculate the signal metric values corresponding to the UST vectors respectively based on each UST vector and a plurality of unitary matrices corresponding to the encoded signal, and determine a selected UST signal based on the numerical values of the signal metric values;

[0043] The modulation module is further configured to randomly generate a plurality of baseband symbol vectors based on the UST signal and the initial parameters, calculate the signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine the selected baseband symbol vector based on the values of the signal secondary peak metric values, and obtain the synchronization sequence corresponding to the UST signal;

[0044] The modulation module is further configured to perform UST modulation in combination with the synchronization sequence to obtain a modulated signal;

[0045] A signal transmitting module, configured to transmit the modulated signal through the signal transmitting end.

[0046] In a third aspect, an embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the method provided in the first aspect or any implementation manner of the first aspect of the embodiment of the present application is implemented.

[0047] In a fourth aspect, the present application further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method provided in the first aspect or any implementation manner of the first aspect of the embodiment of the present application is implemented.

[0048] The beneficial effects brought by the technical solutions provided in some embodiments of the present application at least include:

[0049] A signal transmission method based on an improved Link-16 data link provided by an embodiment of the present application encodes the signal to be encoded through a high-order parity-check matrix to obtain an encoded signal. Higher coding gain can be obtained based on high-order LDPC coding. The UST signal is selected through unitary space-time modulation. A synchronization sequence with strong autocorrelation and weak cross-correlation can be obtained through the UST signal. Thus, on the premise of meeting the data segment demodulation ability requirements, not only can the synchronization signal characteristics be concealed, but also the synchronization segment is not easily detected and recognized. The modulated signal can enhance the anti-interception ability and anti-fading ability while maintaining the same anti-jamming ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present application or related technologies, the following will briefly introduce the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0051] Figure 1 It is a schematic diagram of the architecture of a signal transmission system based on an improved Link-16 data link provided by an embodiment of the present application;

[0052] Figure 2 It is a schematic flowchart of a signal transmission method based on an improved Link-16 data link provided by an embodiment of the present application;

[0053] Figure 3 It is a schematic diagram of the UST signal-to-noise ratio of a signal transmission method based on an improved Link-16 data link provided by an embodiment of the present application;

[0054] Figure 4 It is a schematic diagram of the antenna gain effect of a signal transmission method based on an improved Link-16 data link provided by an embodiment of the present application;

[0055] Figure 5 It is one of the schematic diagrams of the error performance of a signal transmission method based on an improved Link-16 data link provided by an embodiment of the present application;

[0056] Figure 6 It is the second schematic diagram of the error performance of a signal transmission method based on an improved Link-16 data link provided by an embodiment of the present application;

[0057] Figure 7 It is a schematic structural diagram of a signal transmission device based on an improved Link-16 data link provided by an embodiment of the present application;

[0058] Figure 8 It is a schematic structural diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0059] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0060] The terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned accompanying drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or modules is not limited to the listed steps or modules, but optionally further includes steps or modules not listed, or optionally further includes other steps or modules inherent to these processes, methods, products or devices.

[0061] It should be noted that the terms "first" and "second" involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first" and "second" can be interchanged in a specific order or sequence when permitted. It should be understood that the objects distinguished by "first" and "second" can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those described or illustrated herein.

[0062] Specifically, in the related art, in the Link-16 data link standard, the duration of each time slot can be 7.8125 ms, which can include 16×2 = 32 hops of coarse synchronization, 4×2 = 8 hops of fine synchronization, and 16×2 = 32 hops of header. Each time slot can transmit a header and several message words, where the header contains 35-bit information and each message word contains 70-bit information. The duration of each hop is 13 ms, and the symbol rate is 5 Msps.

[0063] The related art generally encodes through RS codes. RS codes are a type of high-order linear block code with strong error-correcting ability against erasures, and are modulated through minimum shift keying and cyclic code shift keying. Among them, minimum shift keying (MSK) is a digital modulation technique with a modulation order of 2, that is, 1 bit is transmitted per symbol period (log22 = 1 bit), and cyclic code shift keying (CCSK) is a soft spread spectrum technique that uses coding to increase redundancy to achieve spectrum expansion, with several information bits corresponding to a pseudo-random codeword, and the expansion multiple is not large and not necessarily an integer multiple.

[0064] However, the signal transmission method based on the improved Link-16 data link provided by the present application encodes through the low density parity check (LDPC) method instead of RS codes, which can provide higher coding gain. By replacing MSK cascaded with CCSK with low-speed unitary space-time modulation (USTM), the anti-interception ability and anti-fading ability can be enhanced while maintaining the same anti-interference ability, and at the same time, the concealment degree of the signal can also be improved.

[0065] Next, please refer to Figure 1 , which is a schematic structural diagram of a signal transmission system based on the improved Link-16 data link provided by an exemplary embodiment of the present application. As Figure 1 shown, the computing system includes a signal transmitting end 201 and a signal receiving end 202.

[0066] Among them, both the signal receiving end and the signal transmitting end can be vehicles such as cars and ships, which are carriers of transmitting devices with relatively high transmitting power (800w), or receiving and transmitting base stations. Among them, the signal receiving end can have multiple transmitting antennas, the signal receiving end can have multiple receiving antennas, and the signal receiving end and the signal transmitting end can have different numbers of antennas.

[0067] Among them, the signal receiving end 101 can be configured to obtain the signal to be encoded and the initial parameters of the signal transmitting end, construct a high-order parity-check matrix based on the initial parameters, and encode the signal to be encoded through the high-order parity-check matrix to obtain an encoded signal;

[0068] The signal receiving end 101 can also randomly generate multiple UST vectors based on the initial parameters, calculate the signal metric values corresponding to the UST vectors respectively based on each UST vector and the multiple unitary matrices corresponding to the encoded signal, and determine the selected UST signal based on the numerical values of the signal metric values;

[0069] Furthermore, the signal receiving end 101 can also randomly generate multiple baseband symbol vectors based on the UST signal and the initial parameters, calculate the signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine the selected baseband symbol vector based on the numerical values of the signal secondary peak metric values, and obtain the synchronization sequence corresponding to the UST signal;

[0070] Finally, the signal receiving end 101 can also perform UST modulation in combination with the synchronization sequence, thereby obtaining a modulated signal, and finally transmitting the modulated signal to the signal receiving end 102 through the multiple transmitting antennas carried.

[0071] The following will explain the present application in detail with specific embodiments.

[0072] Next, in combination with Figure 1 , taking the signal receiving end executing a signal transmission method based on an improved Link-16 data link as an example, an improved Link-16 data link-based signal transmission method provided by the embodiments of the present application will be introduced. For details, please refer to Figure 2 , Figure 2 shows a schematic flow chart of an improved Link-16 data link-based signal transmission method provided by the embodiments of the present application. As Figure 2 shown, the method includes the following steps:

[0073] S201, obtain the signal to be encoded and the initial parameters of the signal transmitting end.

[0074] Specifically, the signal to be encoded can be a data packet given by the user on the signal transmitting end that needs to be transmitted to the signal receiving end. The initial parameters of the signal transmitting end include the total number of transmitting antennas M of the signal transmitting end A, data rate R, channel coherence time T, order L of the signal, number of rows M of the parity-check matrix C , number of columns N of the parity-check matrix C , set {Φ} of unitary matrices corresponding to the signal to be encoded.

[0075] Among them, the data rate R represents bits / symbol period. For example, if 5 bits of source data are transmitted in 32 symbol periods, then R = 5 / 32 and the order L of the signal = 2 RT ; if R = 5 / 32 and the channel coherence time T = 32, then the calculated signal order L = 2^5 = 32.

[0076] The channel coherence time T has no unit and is specifically the number of symbol periods, that is, there are T symbol periods within the channel coherence time, indicating that the channel fading coefficient remains unchanged within the channel coherence time and independently becomes another value in the next set of T symbol periods. Then the definition of the unitary matrix is:

[0077]

[0078] The norm of the unitary matrix is 1: ||Φ|| F = 1;

[0079] The process of constructing the set of all available unitary matrices includes:

[0080] The initial unitary matrix Φ0 corresponding to symbol 0 of the signal to be encoded can be determined, that is, M columns of the T×T DFT matrix are multiplied by Based on the initial unitary matrix Φ0, the unitary matrix Φ corresponding to each order can be determined l :

[0081] Φ l = Θ l Φ0;

[0082] where l = 0, …, L - 1, and Θ l is the diagonal matrix of the signal matrix corresponding to order l;

[0083] Thus, the set {Φ} of unitary matrices corresponding to the signal to be encoded can be obtained. The signal matrix of the signal to be encoded is denoted as X, and the dimension of the signal matrix is T×M A , and the dimension of the unitary matrix is T×M A .

[0084] S202. Based on the initial parameters, a high-order parity-check matrix is constructed, and the signal to be encoded is encoded by the high-order parity-check matrix to obtain the encoded signal.

[0085] Specifically, when performing signal encoding, the total number of transmit antennas M at the signal transmitter end in the initial parameters needs to be obtained A , data rate R, channel coherence time T, order L of the signal, number of rows M of the parity-check matrixC 、The number of columns N of the parity-check matrix C , and the initial unitary matrix Φ0 in the set of unitary matrices {Φ}.

[0086] In some embodiments, the steps of constructing a high-order parity-check matrix based on initial parameters include the following steps:

[0087] S2021, randomly generate a first parity-check matrix H0 based on the PEG algorithm; select random integers uniformly distributed in the first preset range [1, L - 1] as the elements in the second parity-check matrix H1 to generate the second parity-check matrix; the dimensions of the first parity-check matrix and the second parity-check matrix are both M C ×N C ;

[0088] S2022, combine the first parity-check matrix H0 and the second parity-check matrix H1 to construct a high-order parity-check matrix H M , and apply the formula:

[0089] H M = H0.×H1;

[0090] Where, ".×" means that the elements in the corresponding matrix positions of the two matrices are directly multiplied, that is, the elements in each position are multiplied. The PEG algorithm, namely the Progressive Edge-Growth algorithm, is a method for generating the parity-check matrix of LDPC codes.

[0091] The parity-check matrix metric value of the high-order parity-check matrix can be calculated based on the following steps, including:

[0092] S2023, randomly generate a symbol sequence s with the symbol length K participating in encoding, and each element in the symbol sequence is an arbitrary field element in the Galois field GF(L); C It should be noted that LDPC codes are linear block codes, and the first part is information symbols with a length of K

[0093] , and the second part is parity-check symbols with a length of M C , so the total code length is N C = K C + M C 。 C 。

[0094] K C is the input condition of the design. Taking Link-16 as an example, the K C of the message word is 15, and the K C of the header is 7.

[0095] S2024, based on the high-order parity-check matrix H MPerform high - order LDPC encoding on the symbol sequence s to obtain a codeword sequence c of length N, which is the number of columns of the parity - check matrix. C ;

[0096] In S2025, perform USTM mapping on the codeword sequence c to obtain a first USTM signal unitary matrix sequence of quantity N, which is the number of columns of the parity - check matrix, from the set of unitary matrices {Φ}. C

[0097] In S2026, calculate the parity - check matrix metric value z corresponding to the high - order parity - check matrix based on the first USTM signal unitary matrix sequence, and apply the formula:

[0098]

[0099] where the superscript H of Φ0 represents the conjugate transpose of the matrix, and Φ n represents the nth unitary matrix in the first USTM signal unitary matrix sequence ;

[0100] If the parity - check matrix metric value z is less than the parity - check matrix metric value threshold z', or the number of times the parity - check matrix metric value is calculated is greater than the first preset number of iterations, then execute S2027; otherwise, jump to the step of S2021.

[0101] In S2027, output the parity - check matrix metric value and the corresponding high - order parity - check matrix.

[0102] In this way, the parity - check matrix metric value z can be used to measure the quality of the high - order parity - check matrix. By continuously performing iterative calculations to find the smallest possible parity - check matrix metric value, the corresponding high - order parity - check matrix can, after being applied to the encoded signal, reduce the bit - error rate as much as possible and reduce the transmission power of the signal.

[0103] Furthermore, the source data to be encoded can be encoded based on the high - order parity - check matrix to construct an encoded signal.

[0104] In some embodiments, a first preset number of iterations can be given, and an initial parity - check matrix metric value can be given. After each calculation of the parity - check matrix metric value, if the newly calculated parity - check matrix metric value is less than the initial parity - check matrix metric value, then replace the initial parity - check matrix metric value with the newly calculated parity - check matrix metric value, increment the iteration count by 1, and jump to the step of S2021; if the newly calculated parity - check matrix metric value is greater than or equal to the initial parity - check matrix metric value, increment the iteration count by 1 and jump to the step of S2021 until the iteration count is greater than the first preset number of iterations.

[0105] Exemplarily, if \(R = 5 / 32\), \(L = 32\), and \(T = 32\), a \(16\times31\) high - order LDPC code parity - check matrix suitable for USTM can be constructed. This coding method can be used for message words as shown in Table 1 below:

[0106] Table 1 \(16\times31\) high - order LDPC code parity - check matrix for message words

[0107]

[0108] A \(9\times16\) high - order LDPC code parity - check matrix suitable for USTM can also be constructed. This coding method can be used for headers as shown in Table 2 below:

[0109] Table 2 \(9\times16\) USTM symbol - level LDPC code parity - check matrix for headers

[0110]

[0111] Furthermore, based on the encoded signal matrix for modulation, steps S203 - S204 are performed:

[0112] S203, search for the optimal UST signal: Randomly generate multiple UST vectors based on the initial parameters, calculate the signal metric values corresponding to each UST vector based on each UST vector and multiple unitary matrices corresponding to the encoded signal, and determine the selected UST signal based on the values of the signal metric values.

[0113] Specifically, when searching for the optimal UST signal, the total number of transmit antennas \(M\) at the signal transmitter end in the initial parameters needs to be obtained A 、data rate \(R\), channel coherence time \(T\), order \(L\) of the signal, and initial unitary matrix \(\varPhi_0\) in the set of unitary matrices \(\{\varPhi\}\).

[0114] In some embodiments, S203 specifically includes:

[0115] S2031, select random integers uniformly distributed in the second preset range \([0,L - 1]\) as the elements in the UST vector \(u\), and generate a UST vector \(u\) with length \(T\);

[0116] Map the UST vector \(u\) to a complex vector \(\theta\), and apply the formula:

[0117] \(\theta=\exp(j\cdot2\pi u / L)\);

[0118] Based on the complex vector \(\theta\), construct a diagonal matrix \(\varTheta\), and apply the formula:

[0119] \(\varTheta = Diag(\theta)\);

[0120] S2032, calculate each constellation point respectively, and obtain each unitary matrix \(\varPhi\) corresponding to the order \(l = 0,\cdots,l - 1\)l ', apply the formula:

[0121] Φ l ' = Θ l Φ0

[0122] Calculate separately Perform SVD decomposition to extract diagonal elements

[0123] Calculate the metric value e corresponding to each constellation point l l :

[0124]

[0125] Obtain the metric values e of all constellation points l Form a set of signal metric values;

[0126] S2033, output the maximum value in the set of signal metric values as the signal metric value δ corresponding to the UST vector, and apply the formula:

[0127] δ = max(z1,...,z t ,...,z L-1 );

[0128] If the signal metric value δ corresponding to the UST vector is less than the signal metric value threshold δ', or the number of times the signal metric value is calculated is greater than the second preset iteration number, then execute S2034; otherwise, go to the step of S2031 for iterative calculation;

[0129] S2034, output the UST vector and the corresponding signal metric value to obtain the UST signal.

[0130] In this way, a UST signal with as small a signal metric value as possible can be extracted. The smaller the signal metric value, the lower the transmission power required for the corresponding UST signal and the farther the transmission distance of the signal.

[0131] Exemplarily, if R = 5 / 32, T = 32, M A = 1, 2,..., 15, 16, the UST vectors and signal metric values of the USTM constellation calculated can be as shown in Table 1 below. The optimal UST vectors and signal metric values corresponding to different numbers of transmit antennas are often different, which further enriches the signal types and increases the difficulty of non-cooperative signal recognition:

[0132] Table 3 Examples of UST vectors and signal metric values of the USTM constellation

[0133]

[0134] S204. Calculate the synchronization sequence based on the UST signal: Randomly generate multiple baseband symbol vectors based on the UST signal and initial parameters, calculate the signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine the selected baseband symbol vector based on the values of the signal secondary peak metric values, and obtain the synchronization sequence corresponding to the UST signal.

[0135] Specifically, when calculating the synchronization sequence, it is necessary to obtain the total number of transmitting antennas M at the signal transmitting end in the initial parameters A , data rate R, channel coherence time T, order L of the signal, and initial unitary matrix Φ0 in the set of unitary matrices {Φ}. The length K of the UST signal can also be specified, and the baseband symbol length is KT.

[0136] In some embodiments, S204 includes:

[0137] S2041. Select random integers uniformly distributed in the second preset range [0, L - 1] as the elements in the baseband symbol vector s, and generate a baseband symbol vector p with a length of K;

[0138] S2042. Perform USTM mapping on the baseband symbol vector p, and select a second UST signal unitary matrix sequence {Φ} with the number of elements K in the baseband symbol vector from the set of unitary matrices K ;

[0139] where each signal unitary matrix in the second UST signal unitary matrix sequence is T × M A ;

[0140] S2043. Convert the second UST signal unitary matrix sequence into a two-dimensional matrix, including:

[0141] Concatenate every two adjacent matrices in the T × M A × K second UST signal unitary matrix sequence front to back to obtain a two-dimensional matrix X' of T × M A K.

[0142] S2044. Concatenate a zero matrix at the front and back of the two-dimensional matrix to obtain a concatenated matrix, including:

[0143] Based on concatenating a zero matrix Z of (K - 1) × M A at the front and back of the two-dimensional matrix, obtain the concatenated matrix X.

[0144] S2045. Calculate the signal secondary peak metric value corresponding to the baseband symbol vector based on the concatenated matrix and the two-dimensional matrix, including:

[0145] Take the k-th row to the (k + K - 1)-th row in the concatenated matrix to obtain a temporary matrix X Tm x; where k = 1, 2,..., K - 2;

[0146] Based on each temporary matrix X Tmp Calculate the signal secondary peak metric values respectively:

[0147]

[0148] Obtain K - 1 metric values, let z k-1 = 0, so as to eliminate the main peak;

[0149] Take the maximum value among the remaining K - 2 metric values to obtain the signal secondary peak metric value v, and apply the formula:

[0150] v = max(z);

[0151] If the signal secondary peak metric value is less than the signal secondary peak metric value threshold, or the number of times the signal secondary peak metric value is calculated is greater than the third preset iteration number threshold, then execute S2046; otherwise, transfer to the steps of S2041.

[0152] S2046, output the corresponding baseband symbol vector to obtain the selected UST signal, that is, the synchronization sequence corresponding to the preferred UST signal.

[0153] In this way, a baseband symbol vector p with as small a signal secondary peak as possible can be selected, thereby reducing the bit error rate, making the characteristics of the modulated signal less recognizable, and thus having stronger concealment characteristics.

[0154] In some embodiments, KT can also be selected as the initial value of the signal secondary peak, and a new signal secondary peak is updated through the steps of S2041 - S2045. If the new signal secondary peak is less than the initial value of the signal secondary peak, then use the new signal secondary peak to replace the initial value of the signal secondary peak, and jump to the steps of S2041 until the number of times of iteratively calculating the signal secondary peak is greater than a given threshold, or the value of the calculated signal secondary peak is less than the signal secondary peak threshold, which indicates that the signal secondary peak as small as possible has been found.

[0155] Finally, execute S205, perform UST modulation in combination with the synchronization sequence to obtain the modulated signal, and transmit the modulated signal through the signal transmitter.

[0156] Specifically, in S205, the entire data packet of the link16 data link can be modulated by UST in combination with the synchronization sequence, and then the signal is encapsulated according to the message encapsulation structure of LINK16, and then the modulated signal can be transmitted. The embodiments of the present application do not limit this.

[0157] In some embodiments, based on the UST signal obtained from the embodiments of the present application, a correct synchronization probability of 200% can be achieved at a signal-to-noise ratio of -13 dB, and this signal-to-noise ratio can meet the data performance of all rate levels, such asFigure 3 as shown

[0158] As Figure 4 shown is a schematic diagram of the gain effect of antennas under different combinations of the number of antennas, and the error performance of CCSK and USTM when R = 5 / 32 and T = 32. It can be seen that when the number of transmit antennas is 1, the error performance curves of CCSK and USTM with the same number of receive antennas almost overlap, indicating that they have the same error performance. CCSK is not convenient for space-time coding, while USTM, as a non-coherent space-time code, can be easily extended to multiple transmit antennas. With the same number of receive antennas, as the number of transmit antennas increases, diversity gain can also be obtained. When the number of receive antennas is 1, compared with a single transmit antenna, the gain of two transmit antennas is about 20 dB, and four transmit antennas can further provide a gain of more than 20 dB. Fixing the number of other receive antennas, the increase in transmit antennas can also provide gain.

[0159] In some embodiments, based on the method provided in the embodiments of the present application, the performance of the LINK16 time slot is improved. Taking the message encapsulation structure of STDP with the lowest rate as an example, Figures 5-6 is a schematic diagram of the error performance of improving the coding and modulation scheme for the STDP message encapsulation structure, Figure 5 is the bit error rate, Figure 6 is the packet error rate. From Figures 5-6 it can be found that under the condition of single transmit and single receive, compared with the current RS code concatenated CCSK scheme, the high-order LDPC code concatenated USTM scheme proposed in the embodiments of the present application can obtain a gain of more than 2 dB. Two transmit and two receive can provide an additional 3 dB gain. In addition, four transmit and four receive can further provide a 1 dB gain.

[0160] The following is the device embodiment of the present application, which can be used to execute the method embodiment of the present application. For details not disclosed in the device embodiment of the present application, please refer to the method embodiment of the present application.

[0161] Next, please refer to Figure 7 , which is a schematic diagram of the structure of a signal transmission device based on an improved Link-16 data link provided in an exemplary embodiment of the present application. This device can be implemented as all or part of a terminal through software, hardware, or a combination of both, and can also be integrated as an independent module on a server. The signal transmission device based on the improved Link-16 data link in the embodiments of the present application can be applied to a terminal or the cloud. The device 70 includes a data acquisition module 701, a coding module 702, a modulation module 703, and a signal transmission module 704, where:

[0162] The data acquisition module 701 is used to acquire the signal to be encoded and the initial parameters of the signal transmitter;

[0163] The encoding module 702 is used to construct a high-order parity-check matrix based on the initial parameters, and encode the signal to be encoded through the high-order parity-check matrix to obtain an encoded signal;

[0164] The modulation module 703 is used to randomly generate a plurality of UST vectors based on the initial parameters, calculate the signal metric values corresponding to the UST vectors respectively based on each UST vector and the plurality of unitary matrices corresponding to the encoded signal, and determine the selected UST signal based on the numerical values of the signal metric values;

[0165] The modulation module 703 is further used to randomly generate a plurality of baseband symbol vectors based on the UST signal and the initial parameters, calculate the signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine the selected baseband symbol vector based on the numerical values of the signal secondary peak metric values, and obtain the synchronization sequence corresponding to the UST signal;

[0166] The modulation module 703 is further used to perform UST modulation in combination with the synchronization sequence to obtain a modulated signal;

[0167] The signal transmitting module 704 is used to transmit the modulated signal through the signal transmitting end.

[0168] It should be noted that when the device 70 provided in the above embodiment executes the signal transmission method based on the improved Link-16 data link, only the above-mentioned division of each functional module is used for illustration. In practical applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device provided in the above embodiment and the embodiment of the signal transmission method based on the improved Link-16 data link belong to the same concept, and the implementation process thereof is detailed in the method embodiment, which will not be repeated here.

[0169] The embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the method in any of the above embodiments are implemented.

[0170] Please refer to Figure 8 , which is a structural block diagram of an electronic device provided by the embodiment of the present application.

[0171] As Figure 8 shown, the electronic device 800 includes a processor 801 and a memory 802.

[0172] In the embodiments of the present application, the processor 801 is the control center of the computer system, which can be the processor of a physical machine or the processor of a virtual machine. The processor 801 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 801 may be implemented in at least one of the following hardware forms: DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array).

[0173] The processor 801 may also include a main processor and a coprocessor. The main processor is a processor used to process data in the wake state, also known as the CPU (Central Processing Unit); the coprocessor is a low-power processor used to process data in the standby state.

[0174] The memory 802 may include one or more computer-readable storage media, and the computer-readable storage media may be non-transitory. The memory 802 may further include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash storage devices. In some embodiments of the present application, the non-transitory computer-readable storage media in the memory 802 is used to store at least one instruction, and the at least one instruction is used to be executed by the processor 801 to implement the method in the embodiments of the present application.

[0175] In some embodiments, the electronic device 800 further includes: a peripheral device interface 803 and at least one peripheral device 804. The processor 801, the memory 802, and the peripheral device interface 803 may be connected through a bus or signal lines. Each peripheral device 804 may be connected to the peripheral device interface 803 through a bus, signal lines, or a circuit board. Specifically, the peripheral device 804 includes: a display screen, a camera, and an audio circuit. The peripheral device interface 803 may be used to connect at least one peripheral device related to I / O (Input / Output) to the processor 801 and the memory 802.

[0176] In some embodiments of the present application, the processor 801, the memory 802, and the peripheral device interface 803 are integrated on the same chip or circuit board; in some other embodiments of the present application, any one or two of the processor 801, the memory 802, and the peripheral device interface 803 may be implemented on a separate chip or circuit board. The embodiments of the present application do not make specific limitations in this regard.

[0177] The block diagram of the electronic device shown in the embodiments of the present application does not limit the electronic device 800. The electronic device 800 may include more or fewer components than shown in the figure, combine some components, or adopt different component arrangements.

[0178] The embodiments of the present application also provide a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the steps of the method in any of the foregoing embodiments are implemented. Among them, the computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0179] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence, or the part that contributes to the related technologies, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disks, optical disks, etc., and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them. Although the present application 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 described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. 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 application.

Claims

1. A signal transmission method based on an improved Link-16 data link, characterized in that Applied to the signal transmitting end, the method includes: Obtain the signal to be encoded and the initial parameters of the signal transmitting end; Construct a high-order parity-check matrix based on the initial parameters, and encode the signal to be encoded through the high-order parity-check matrix to obtain an encoded signal; Randomly generate multiple UST vectors based on the initial parameters, calculate the signal metric values corresponding to the UST vectors respectively based on each UST vector and multiple unitary matrices corresponding to the encoded signal, and determine the selected UST signal based on the values of the signal metric values; Randomly generate multiple baseband symbol vectors based on the UST signal and the initial parameters, calculate the signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine the selected baseband symbol vector based on the values of the signal secondary peak metric values, and obtain the synchronization sequence corresponding to the UST signal; Perform UST modulation in combination with the synchronization sequence to obtain a modulated signal, and transmit the modulated signal through the signal transmitting end.

2. The signal transmission method based on the improved Link-16 data link according to claim 1, characterized in that The initial parameters include the total number of transmitting antennas of the signal transmitting end, data rate, channel coherence time, order of the signal, number of rows of the parity-check matrix, number of columns of the parity-check matrix, and the set of unitary matrices corresponding to the signal to be encoded.

3. The signal transmission method based on the improved Link-16 data link according to claim 2, wherein The constructing a high-order parity-check matrix based on the initial parameters includes: Randomly generate a first parity-check matrix based on the PEG algorithm, select random integers uniformly distributed in a first preset range as the elements in the second parity-check matrix, generate the second parity-check matrix, and construct a high-order parity-check matrix by combining the first parity-check matrix and the second parity-check matrix; Calculate the parity-check matrix metric value corresponding to the high-order parity-check matrix. If the parity-check matrix metric value is less than the parity-check matrix metric value threshold, or the number of times of calculating the parity-check matrix metric value is greater than the first preset iteration number, output the parity-check matrix metric value and the corresponding high-order parity-check matrix; otherwise, go to the step of randomly generating the first parity-check matrix based on the PEG algorithm; Wherein, the number of rows of the first parity-check matrix and the second parity-check matrix is the number of rows of the parity-check matrix, the number of columns of the first parity-check matrix and the second parity-check matrix is the number of columns of the parity-check matrix, and the lower limit of the first preset range is greater than or equal to 1 and the upper limit is less than or equal to the order of the signal minus 1.

4. A signal transmission method based on an improved Link-16 data link according to claim 3, characterized in that The calculating the parity-check matrix metric value corresponding to the high-order parity-check matrix includes: Randomly generate a symbol sequence with the symbol length participating in encoding, and each element in the symbol sequence is an arbitrary field element in the Galois field; Perform high-order LDPC encoding on the symbol sequence based on the high-order parity-check matrix to obtain a codeword sequence with the length of the number of columns of the parity-check matrix; Perform USTM mapping on the codeword sequence to obtain a first UST signal unitary matrix sequence with the number of columns of the parity-check matrix from the set of unitary matrices; Calculate the parity-check matrix metric value corresponding to the high-order parity-check matrix based on the first UST signal unitary matrix sequence.

5. A signal transmission method based on an improved Link-16 data link according to claim 2, characterized in that, The randomly generating multiple UST vectors based on the initial parameters, calculating the signal metric values corresponding to the UST vectors respectively based on each UST vector and multiple unitary matrices corresponding to the encoded signal, and determining the selected UST signal based on the values of the signal metric values includes: Select random integers uniformly distributed in the second preset range as the elements in the UST vector, generate the UST vector, map the UST vector into a complex vector, and construct a diagonal matrix based on the complex vector; Calculate the unitary matrix corresponding to each constellation point respectively based on the diagonal matrix and the initial unitary matrix corresponding to symbol 0 in the set of unitary matrices, and calculate the set of signal metric values of all constellation points based on the unitary matrix corresponding to each constellation point; Output the maximum value in the set of signal metric values as the signal metric value corresponding to the UST vector; If the signal metric value corresponding to the UST vector is less than the signal metric value threshold, or the number of times of calculating the signal metric value is greater than the second preset iteration number, output the UST vector and the corresponding signal metric value to obtain the UST signal; otherwise, go to the step of selecting random integers uniformly distributed in the second preset range as the elements in the UST vector; Wherein, the length of the UST vector is equal to the number of symbol periods, the lower limit of the second preset range is greater than or equal to 0, and the upper limit is less than or equal to the order of the signal minus 1.

6. The signal transmission method based on the improved Link-16 data link according to claim 5, wherein The method of randomly generating a plurality of baseband symbol vectors based on the UST signal and the initial parameters, calculating the signal secondary peak metric value corresponding to each baseband symbol vector respectively, and determining the selected baseband symbol vector based on the value of the signal secondary peak metric value to obtain the synchronization sequence corresponding to the UST signal includes: Select random integers uniformly distributed in the second preset range as the elements in the baseband symbol vector to generate the baseband symbol vector; Perform USTM mapping on the baseband symbol vector, and select the second UST signal unitary matrix sequence with the number of elements in the baseband symbol vector from the set of unitary matrices; Convert the second UST signal unitary matrix sequence into a two-dimensional matrix; Concatenate a zero matrix at the front and back of the two-dimensional matrix respectively to obtain a concatenated matrix; Calculate the signal secondary peak metric value corresponding to the baseband symbol vector based on the concatenated matrix and the two-dimensional matrix; If the signal secondary peak metric value is less than the signal secondary peak metric value threshold, or the number of times of calculating the signal secondary peak metric value is greater than the third preset iteration number threshold, output the corresponding baseband symbol vector to obtain the synchronization sequence corresponding to the selected UST signal; otherwise, go to the step of selecting random integers uniformly distributed in the second preset range as the elements in the baseband symbol vector.

7. A signal transmission method based on an improved Link-16 data link according to claim 6, characterized in that The calculating the signal secondary peak metric value corresponding to the baseband symbol vector based on the concatenated matrix and the two-dimensional matrix includes: Take the k-th row to the (k + K - 1)-th row in the concatenated matrix to obtain a temporary matrix X Tmp ; Calculate all metric values based on each temporary matrix and the two-dimensional matrix to form a set of signal secondary peak metric values; Take the maximum value in the set of signal secondary peak metric values to obtain the signal secondary peak metric value corresponding to the baseband symbol vector; Wherein, K is the number of elements in the baseband symbol vector, k represents the k-th row in the concatenated matrix, and k is an integer greater than or equal to 0 and less than or equal to K - 2.

8. A signal transmission device based on an improved Link-16 data link, characterized in that, Including: A data acquisition module for acquiring the signal to be encoded and the initial parameters of the signal transmitter; An encoding module, configured to construct a high-order parity-check matrix based on the initial parameters, and encode the signal to be encoded through the high-order parity-check matrix to obtain an encoded signal; A modulation module, configured to randomly generate a plurality of UST vectors based on the initial parameters, calculate signal metric values corresponding to each UST vector respectively based on each UST vector and a plurality of unitary matrices corresponding to the encoded signal, and determine a selected UST signal based on the values of the signal metric values; The modulation module is further configured to randomly generate a plurality of baseband symbol vectors based on the UST signal and the initial parameters, calculate signal secondary peak metric values corresponding to each baseband symbol vector respectively, determine a selected baseband symbol vector based on the values of the signal secondary peak metric values, and obtain a synchronization sequence corresponding to the UST signal; The modulation module is further configured to perform UST modulation in combination with the synchronization sequence to obtain a modulated signal; A signal transmitting module, configured to transmit the modulated signal through the signal transmitting end.

9. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, the steps of the method according to any one of claims 1 to 7 are implemented.

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

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