Short-wave communication-oriented OTSM-SCMA signal sending method and receiving method

Abstract

The invention discloses an OTSM-SCMA signal sending method and receiving method oriented to short-wave communication, and belongs to the technical field of communication, the sending method comprises the following steps: performing DS grid mapping according to bit sequences of a plurality of users to be transmitted, and performing superposition to form a superposed DS matrix; carrying out SCMA code word distribution according to the superposed DS matrix to obtain a superposed DS matrix embedded with an SCMA codebook; performing WHT conversion on each row of vectors of the superposition DS matrix embedded with the SCMA codebook to obtain a DT matrix; and performing digital-to-analog conversion on the DT matrix to obtain a continuous time domain signal and sending the continuous time domain signal to a transmission channel. According to the invention, the problem that the interference caused by the high peak-to-average power ratio of the traditional OFDM system, the high coding and decoding complexity of the existing SCMA-OFDM system and the short-wave channel time-frequency double-selective fading cannot be overcome simultaneously in the short-wave communication in the prior art is solved.

Description

Technical Field

[0001] This invention relates to an OTSM-SCMA signal transmission and reception method for shortwave communication, belonging to the field of communication technology. Background Technology

[0002] With the rapid development of information technology and wireless communication technology, shortwave communication, as a key technology in both military and civilian fields, has seen its channel characteristics research and modulation technology optimization become a focus. Due to multipath delay spread and Doppler broadening effects, shortwave channels exhibit significant time-frequency dual-selective fading characteristics, easily leading to decreased communication stability or even outages, creating communication dead zones. To address this problem, Orthogonal Frequency Division Multiplexing (OFDM) technology, with its advantages of reducing multipath interference and eliminating inter-symbol interference due to subcarrier orthogonality, has become the mainstream solution for shortwave communication. However, traditional Orthogonal Multiple Access (OMA) technology is limited by the efficiency of physical layer resource allocation, making it difficult to meet the large-scale user access needs of the 5G era. Therefore, Non-Orthogonal Multiple Access (NOMA) technology has emerged. Among them, Sparse Code Multiple Access (SCMA), as a representative of code-domain NOMA, maps information symbols to multi-dimensional codewords through a user-dedicated codebook and transmits them in vector form. It achieves interference suppression during decoding, effectively improving spectral efficiency and user access capabilities. Furthermore, Orthogonal Time Sequency Multiplexing (OTSM) technology places information symbols in the delay-sequence domain and converts them to the delay time domain. It uses a DS (Delay-Sequency) trellis instead of the traditional DD (Delay-Doppler) trellis, naturally resisting delay spread and Doppler shift, and does not rely on a cyclic prefix (CP), providing a new approach to interference suppression in time-frequency dual-selection channels.

[0003] Existing technologies suffer from three major shortcomings that urgently need to be addressed: First, while traditional OFDM technology can mitigate multipath effects, its peak-to-average power ratio (PAPR) characteristics lead to reduced power amplifier efficiency and increased signal distortion, limiting overall system efficiency. Second, although SCMA-based OFDM systems improve spectral efficiency and access capabilities, their high detection algorithm complexity and excessive encoding / decoding overhead increase system processing latency and implementation costs, making it difficult to meet the low-latency requirements of shortwave communication. Third, time-frequency dual-selective fading in shortwave channels exacerbates inter-symbol interference (ISI) and inter-carrier interference (ICI), which traditional OFDM and SCMA-OFDM systems cannot effectively overcome, resulting in degraded communication quality or even communication interruptions and creating communication dead zones. These shortcomings collectively restrict the performance improvement of shortwave communication in mobile scenarios, necessitating technological innovation to simultaneously address these three core issues: PAPR, high encoding / decoding complexity, and time-frequency dual-selective fading interference. Summary of the Invention

[0004] The purpose of this invention is to provide an OTSM-SCMA signal transmission and reception method for shortwave communication. By combining the non-orthogonal time-frequency structure of OTSM with the sparse codebook design of SCMA, and introducing WHT for preprocessing and post-processing of the user bit sequence to be transmitted, this invention solves the problems that existing technologies cannot simultaneously overcome in shortwave communication, such as the peak-to-average power ratio of traditional OFDM systems, the high encoding and decoding complexity of existing SCMA-OFDM systems, and the interference caused by the time-frequency dual-selective fading of shortwave channels.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution.

[0006] In a first aspect, the present invention provides an OTSM-SCMA signal transmission method for shortwave communication, executed by a transmitting end, comprising:

[0007] DS grid mapping is performed on the bit sequences of multiple users to be transmitted, and the grids are superimposed to form a superimposed DS matrix;

[0008] SCMA codewords are allocated based on the superimposed DS matrix to obtain a superimposed DS matrix embedded in the SCMA codebook;

[0009] Perform a WHT transformation on each row vector of the superimposed DS matrix of the embedded SCMA codebook to obtain the DT matrix;

[0010] The DT matrix is ​​converted from digital to analog to obtain a continuous time-domain signal, which is then sent to the transmission channel.

[0011] Furthermore, a superimposed DS matrix is ​​formed by performing DS trellis mapping based on the user bit sequence to be transmitted, including:

[0012] The bit sequences of multiple users to be transmitted are converted from serial to parallel to obtain a parallel bit stream of multiple users;

[0013] The parallel bitstreams from the multiple users are encoded and interleaved to obtain the interleaved data sequence from the multiple users.

[0014] The interleaved data sequences from the multiple users are filled into a preset DS grid to form a superimposed DS matrix;

[0015] Where the total bandwidth and frame duration of the OTSM system are respectively and Then the superimposed DS matrix transmission User bits, Indicates frequency offset. The superimposed DS matrix represents the effective duration of the interleaved data sequence as follows:

[0016] ;

[0017] In the formula, This represents a superimposed DS matrix, which is a complex matrix with dimension n. The matrix, Indicates the first DS matrix of each user This represents the total number of users, where, Represents the field of complex numbers. Indicates the number of delay axis resources. This indicates the number of sequence axis resources.

[0018] Further, SCMA codeword allocation is performed based on the superimposed DS matrix to obtain a superimposed DS matrix embedded with the SCMA codebook, including:

[0019] Each user is assigned a unique SCMA codebook, represented as follows:

[0020] ;

[0021] In the formula, This represents a superimposed DS matrix embedded in the SCMA codebook;

[0022] By using an overload factor to constrain the number of data symbols, the data symbols in the interleaved data sequence are mapped to the corresponding user's SCMA codebook to generate sparse multidimensional codewords.

[0023] By overlaying the sparse multidimensional codewords of all users, we obtain the fused multi-user data. Superimposed codeword vectors;

[0024] Will The superimposed codeword vectors are placed in the preset DS grid to obtain a superimposed DS matrix embedded in the SCMA codebook;

[0025] The SCMA codebook is preset. The set of sparse codewords, the total number of data symbols transmitted on a single DS frame of the superimposed DS matrix is ​​represented as:

[0026] ;

[0027] In the formula, This represents the total number of data symbols transmitted on a single DS frame with the superimposed DS matrix. Denotes the delayed grid, where, and , This represents the modulo operation, which requires... It is an integer multiple of K. Indicates the maximum reference delay number in the delay axis;

[0028] The overload factor is expressed as:

[0029] ;

[0030] In the formula, Indicates the overload factor, typically, , among which, the The total number of data symbols that a user can transmit in the system is represented as:

[0031] ;

[0032] In the formula, Indicates the first The total number of data symbols that a user can transmit in the system, of which, The concatenated representation of the SCMA codebook is as follows:

[0033] , ;

[0034] In the formula, express Cascade of SCMA codebooks. Indicates the received number DS matrix of each user Indicates the first Each user is assigned the DS matrix corresponding to the first delay axis resource. Indicates the first Each user is assigned the DS matrix corresponding to the second delay axis resource. Indicates the first The user was assigned to the first The DS matrix corresponding to each delay axis resource This represents the superimposed SCMA codebook from all users.

[0035] Further, each row vector of the superimposed DS matrix containing the embedded SCMA codebook is subjected to a WHT transformation to obtain the DT matrix, including:

[0036] Select a WHT matrix whose order matches the number of columns of the superimposed DS matrix of the embedded SCMA codebook;

[0037] The WHT forward transform is performed on each row vector of the superimposed DS matrix embedded in the SCMA codebook using the WHT matrix to convert the sequence domain data into a DT matrix.

[0038] The DT matrix is ​​represented as follows:

[0039] ;

[0040] In the formula, Represents the DT matrix. Represents the number of resources on the sequence axis. Perform WHT forward transform.

[0041] Further, the DT matrix is ​​subjected to digital-to-analog conversion to obtain a continuous time-domain signal, which is then transmitted to the transmission channel, including:

[0042] The DT matrix is ​​traversed element by element according to a preset row priority or column priority order, and the two-dimensional matrix DT data is converted into a one-dimensional vector time-domain sample sequence.

[0043] The one-dimensional vector-form time-domain sample sequence is converted from digital to analog to obtain a continuous time-domain signal;

[0044] Send continuous time-domain signals to the transmission channel;

[0045] The time-domain sample sequence is represented as follows:

[0046] ;

[0047] In the formula, Represents a time-domain sample sequence. Represents the DT matrix Vectorize it.

[0048] Secondly, this invention provides an OTSM-SCMA signal receiving method for shortwave communication, executed by a receiving end, comprising:

[0049] The received continuous time-domain signal is converted from analog to digital to obtain the reconstructed DT matrix;

[0050] The reconstructed DT matrix is ​​subjected to the WHT inverse transformation to reconstruct each row vector of the superimposed DS matrix embedded in the SCMA codebook, thus obtaining the reconstructed superimposed DS matrix embedded in the SCMA codebook.

[0051] SCMA decoding is performed on each row vector of the superimposed DS matrix of the reconstructed embedded SCMA codebook to obtain the reconstructed superimposed DS matrix.

[0052] The reconstructed superimposed DS matrix is ​​split and the bit sequences of multiple users are recovered by inverse mapping of the DS grid;

[0053] The continuous time-domain signal is obtained by the OTSM-SCMA signal transmission method for shortwave communication described in the first aspect.

[0054] Furthermore, the received continuous time-domain signal is subjected to analog-to-digital conversion to obtain the reconstructed DT matrix, including:

[0055] The received continuous time-domain signal is converted from analog to digital to obtain a time-domain sample sequence in one-dimensional vector form;

[0056] The time-domain sample sequence in one-dimensional vector form is traversed element-wise in reverse order according to the preset row priority or column priority order. The time-domain sample data in one-dimensional vector form is reconstructed into a two-dimensional matrix DT matrix, and the reconstructed DT matrix is ​​obtained.

[0057] The reconstructed DT matrix is ​​represented as follows:

[0058] ;

[0059] In the formula, This represents the reconstructed DT matrix.

[0060] Further, the reconstructed DT matrix is ​​subjected to an inverse WHT transformation to obtain each row vector of the reconstructed superimposed DS matrix of the embedded SCMA codebook, including:

[0061] The WHT inverse matrix or WHT matrix that has the same order as the transmitting end and matches the number of columns of the reconstructed DT matrix;

[0062] By performing the WHT inverse transformation on each row vector of the reconstructed DT matrix using the WHT inverse matrix pair or the WHT matrix, the DT field data is transformed and reconstructed into each row vector of the superimposed DS matrix embedded in the SCMA codebook, thus obtaining the reconstructed superimposed DS matrix embedded in the SCMA codebook.

[0063] The superimposed DS matrix of the reconstructed embedded SCMA codebook is represented as follows:

[0064] ;

[0065] In the formula, This represents the superimposed DS matrix of the reconstructed embedded SCMA codebook. This represents the inverse WHT transform.

[0066] Further, SCMA decoding is performed on each row vector of the superimposed DS matrix of the reconstructed embedded SCMA codebook to obtain the reconstructed superimposed DS matrix, including:

[0067] The SCMA detector based on the message passing algorithm uses the effective factor matrix to separate the time-delay domain symbols of all users in each row of the superimposed DS matrix of the reconstructed embedded SCMA codebook through multi-user independent detection.

[0068] The time delay domain symbols corresponding to all users in each row are combined in user order to obtain the reconstructed superimposed DS matrix;

[0069] The effective factor matrix is ​​represented as follows:

[0070] ;

[0071] In the formula, Represents the effective factor matrix, This represents the effective factor parameter corresponding to the first resource node. This represents the effective factor parameter corresponding to the second resource node. This represents the effective factor parameter corresponding to the 3rd resource node. Indicates the first The effective factor parameter corresponding to each resource node is 0, which indicates that the resource node has no SCMA codebook association with a certain user node.

[0072] Further, the reconstructed superimposed DS matrix is ​​split and the bit sequences of multiple users are recovered through inverse DS grid mapping, including:

[0073] The reconstructed superimposed DS matrix is ​​separated into multiple users using an SCMA detector based on a message passing algorithm to obtain the DS matrix for each user.

[0074] The interleaved data sequence is read from each user's DS matrix in the reverse order of the DS grid mapping at the sending end;

[0075] The interleaved data sequence for each user is obtained by reading the DS matrix of each user in reverse order of filling the DS grid;

[0076] Perform a deinterleaving operation on the interleaved data sequence for each user to obtain the encoded sequence for each user;

[0077] The encoded sequence of each user is decoded using a channel decoder corresponding to the transmitting end to obtain the bit stream of each user; the bit stream of each user is then converted from parallel to serial to recover the bit sequence of multiple users.

[0078] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0079] 1. This invention obtains a DT matrix by performing WHT transformation on each row vector of the superimposed DS matrix embedded with SCMA codebook, which can effectively reduce the peak-to-average power ratio of the signal and improve the anti-interference performance of shortwave channel transmission. At the same time, by combining the features of DS grid mapping superposition and SCMA codeword allocation technology, it realizes efficient superposition and differentiation of multi-user signals on spectrum resources. Finally, it forms a continuous time-domain signal through digital-to-analog conversion to complete reliable signal transmission in shortwave communication scenarios. This solves the problem that existing technologies cannot simultaneously overcome the peak-to-average power ratio of traditional OFDM systems, the high encoding and decoding complexity of existing SCMA-OFDM systems, and the interference caused by time-frequency dual-selective fading in shortwave channels in shortwave communication.

[0080] 2. This invention obtains a reconstructed DT matrix by performing analog-to-digital conversion on the received continuous time-domain signal, and then reconstructs each row vector of the superimposed DS matrix embedded with the SCMA codebook through WHT inverse transform. Next, SCMA decoding is performed on each row vector of the reconstructed superimposed DS matrix embedded with the SCMA codebook to obtain a reconstructed superimposed DS matrix. Finally, the reconstructed superimposed DS matrix is ​​split and the bit sequences of multiple users are recovered through DS grid inverse mapping. This achieves efficient and accurate recovery of multi-user bit sequences, improving the reliability of OTSM-SCMA signal reception and multi-user separation capability in shortwave communication scenarios.

[0081] 3. This invention achieves efficient superposition of multi-user signals in shortwave communication scenarios, low peak-to-average power ratio, and reliable transmission, significantly improving system spectral efficiency and anti-interference capability. It also meets the user data symbol transmission requirements under the constraints of total bandwidth and frame duration in OTSM systems.

[0082] 4. This invention obtains a one-dimensional vector time-domain sample sequence by analog-to-digital conversion of the received continuous time-domain signal, and reconstructs it into a two-dimensional DT matrix according to a preset order. Combined with the WHT inverse matrix with the same order as the transmitter, the reconstructed DT matrix is ​​subjected to WHT inverse transform to recover the row vectors of the superimposed DS matrix embedded with the SCMA codebook. Then, using the SCMA detector of the message passing algorithm and the effective factor matrix, the time delay domain symbols are separated by multi-user independent detection and combined to reconstruct the superimposed DS matrix. Finally, the SCMA detector is used for multi-user separation, deinterleaving, channel decoding and parallel-to-serial conversion to recover the bit sequences of multiple users. This invention achieves efficient and accurate recovery of multi-user bit sequences and improves anti-interference performance of the OTSM-SCMA signal receiver in shortwave communication scenarios, significantly enhances multi-user separation capability and data recovery reliability, and meets the complete link requirements of DS grid inverse mapping and channel decoding. Attached Figure Description

[0083] Figure 1 This is a flowchart illustrating an OTSM-SCMA signal transmission method for shortwave communication provided in an embodiment of the present invention.

[0084] Figure 2 This is a flowchart illustrating an OTSM-SCMA signal receiving method for shortwave communication provided in an embodiment of the present invention.

[0085] Figure 3 This is a schematic diagram of the overall process of an OTSM-SCMA signal transmission and reception method for shortwave communication provided by an embodiment of the present invention;

[0086] Figure 4 This is a schematic diagram of the transmission model provided in an embodiment of the present invention;

[0087] Figure 5 This is a schematic diagram of the OTSM-SCMA system provided in an embodiment of the present invention;

[0088] Figure 6 It is a preset DS mesh provided in the embodiments of the present invention. Schematic diagram of superimposed codeword vector allocation. Detailed Implementation

[0089] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0090] Example 1

[0091] like Figure 1 As shown, this embodiment introduces an OTSM-SCMA signal transmission method for shortwave communication, executed by the transmitting end, including:

[0092] Step 1: Perform DS grid mapping based on the bit sequences of multiple users to be transmitted and then superimpose them to form a superimposed DS matrix.

[0093] This embodiment achieves efficient grid-based superposition of multi-user bit sequences on time-frequency resources and spectrum resource reuse by performing DS grid mapping and superimposing the bit sequences of multiple users to be transmitted to form a superimposed DS matrix. This effectively improves the transmission capacity and spectrum utilization of multi-user data within limited bandwidth in shortwave communication scenarios. At the same time, the grid mapping structure provides a basic resource matrix framework for subsequent SCMA codeword allocation.

[0094] Step 2: Perform SCMA codeword allocation based on the superimposed DS matrix to obtain the superimposed DS matrix embedded with the SCMA codebook.

[0095] This embodiment achieves differentiated coding and sparse representation of multi-user signals in the superimposed DS matrix by allocating SCMA codewords based on the superimposed DS matrix and obtaining the superimposed DS matrix with embedded SCMA codebooks. Combined with overload factor constraints and sparse codeword mapping technology, it reduces interference between users, improves the system's anti-multiple access interference capability, and ensures accurate matching between each user's SCMA codeword and the superimposed DS matrix resource grid.

[0096] Step 3: Perform WHT transformation on each row vector of the superimposed DS matrix containing the embedded SCMA codebook to obtain the DT matrix.

[0097] This embodiment obtains the DT matrix by performing WHT transformation on each row vector of the superimposed DS matrix embedded with the SCMA codebook. By utilizing the sequence domain to time domain conversion characteristics of the WHT transformation, the peak-to-average power ratio (PAPR) of the signal is effectively reduced, and the anti-nonlinear distortion capability of shortwave channel transmission is enhanced. At the same time, the sequence domain data is converted into DT domain data, providing a time domain signal structure adapted to shortwave channel transmission for subsequent digital-to-analog conversion.

[0098] Step 4: Perform digital-to-analog conversion on the DT matrix to obtain a continuous time-domain signal and send it to the transmission channel.

[0099] This embodiment achieves accurate conversion from two-dimensional DT matrix data to one-dimensional continuous time-domain signal by performing digital-to-analog conversion on the DT matrix and sending it to the transmission channel. This ensures continuous transmission and reliable transmission of the signal in the shortwave channel. At the same time, through vectorization processing and digital-to-analog conversion, it meets the time-domain signal generation requirements under the constraints of the total bandwidth and frame duration of the OTSM system, ensuring the integrity and effectiveness of signal transmission.

[0100] Example 2

[0101] like Figure 2 As shown, based on the same inventive concept as Embodiment 1, this embodiment introduces an OTSM-SCMA signal receiving method for shortwave communication, executed by the receiving end, including:

[0102] Step 1: Perform analog-to-digital conversion on the received continuous time-domain signal to obtain the reconstructed DT matrix.

[0103] This embodiment achieves accurate conversion from analog signal to digital matrix by performing analog-to-digital conversion on the received continuous time-domain signal, providing a structurally complete input data foundation for subsequent WHT inverse transformation. At the same time, it ensures the accuracy of signal sampling and the integrity of time-domain information in shortwave channel transmission, and supports the reliable start-up of the receiver signal processing link.

[0104] Step 2: Perform the WHT inverse transformation on the reconstructed DT matrix to reconstruct each row vector of the superimposed DS matrix embedded in the SCMA codebook, and obtain the reconstructed superimposed DS matrix embedded in the SCMA codebook.

[0105] This embodiment reconstructs each row vector of the superimposed DS matrix embedded in the SCMA codebook by performing an inverse WHT transform on the reconstructed DT matrix. By utilizing the sequence-time domain inverse mapping characteristic of the WHT transform, the sequence domain structure of the superimposed DS matrix embedded in the SCMA codebook at the transmitting end is effectively restored, reducing the risk of signal distortion during the inverse transform process and ensuring accurate reconstruction and resource grid alignment of multi-user sparse codewords at the receiving end.

[0106] Step 3: Perform SCMA decoding on each row vector of the superimposed DS matrix of the reconstructed embedded SCMA codebook to obtain the reconstructed superimposed DS matrix.

[0107] This embodiment performs SCMA decoding on each row vector of the superimposed DS matrix containing the reconstructed SCMA codebook. Utilizing a message passing algorithm and an effective factor matrix, it achieves independent multi-user detection, effectively separating the delay-domain symbols of each user within the superimposed DS matrix. This improves the accuracy and anti-interference capability of multi-user signal separation, while ensuring precise matching between the SCMA codeword and user data, providing lossless decoded data for subsequent bit sequence recovery. The specific framework is as follows: Figure 3 As shown, It is a bit sequence. The encoded sequence, is the interleaved data sequence, s is the time-domain signal entering the channel, and r is the time-domain signal received after transmission through the channel.

[0108] Step 4: Split the reconstructed superimposed DS matrix and recover the bit sequences of multiple users through inverse DS grid mapping.

[0109] This embodiment splits the reconstructed superimposed DS matrix and recovers the bit sequences of multiple users through DS grid inverse mapping. Combined with deinterleaving, channel decoding, and parallel-to-serial conversion processes, it achieves end-to-end recovery from the superimposed DS matrix to the original bit sequences of multiple users. This ensures accurate reconstruction and complete transmission of multi-user data in shortwave communication scenarios, while meeting the complete link requirements of DS grid inverse mapping and channel decoding, and improving the global reliability of receiver data processing and the integrity of user data recovery.

[0110] The continuous time-domain signal is obtained by the OTSM-SCMA signal transmission method for shortwave communication described in Example 1.

[0111] Example 3

[0112] Figure 5 This is a schematic diagram of the OTSM-SCMA system. Figure 5 In the diagram, G1 represents the time-domain signal transmitted by user 1 in the channel, G2 represents the time-domain signal transmitted by user 2 in the channel, G3 represents the time-domain signal transmitted by user j in the channel, r1 represents the time-domain signal received by user 1, r2 represents the time-domain signal received by user 1, and r3 represents the time-domain signal received by user 1. In the OTSM-SCMA system, a DS grid is used to modulate information symbols, instead of the traditional DD grid. The transmission model is configured such that the DS grid at the transmitting end is transformed to a DT grid via WHT, and after parallel-to-serial conversion and digital-to-analog conversion, it is transmitted to the channel. The receiving end performs the corresponding inverse processing at the transmitting end. The transmission model is as follows: Figure 4 As shown.

[0113] Based on the same inventive concept as other embodiments, such as Figure 3 As shown, this embodiment introduces the implementation steps of an OTSM-SCMA signal transmission and reception method for shortwave communication, including:

[0114] Step 1: Perform DS grid mapping based on the bit sequences of multiple users to be transmitted and then superimpose them to form a superimposed DS matrix.

[0115] Step 1.1: Perform serial-to-parallel conversion on the bit sequences of multiple users to be transmitted to obtain a parallel bit stream of multiple users.

[0116] Step 1.2: Encode and interleave the parallel bit streams of the multiple users to obtain the interleaved data sequence of the multiple users.

[0117] Step 1.3: Fill the interleaved data sequences of the multiple users into a preset DS grid to form a superimposed DS matrix.

[0118] In this embodiment, if the total bandwidth and frame duration of the OTSM system are respectively and Then the superimposed DS matrix transmission User bits, Indicates frequency offset. The superimposed DS matrix represents the effective duration of the interleaved data sequence as follows:

[0119] ;

[0120] In the formula, This represents a superimposed DS matrix, which is a complex matrix with dimension n. The matrix, Indicates the first DS matrix of each user This represents the total number of users, where, Represents the field of complex numbers. Indicates the number of delay axis resources. This indicates the number of sequence axis resources.

[0121] Step 2: Perform SCMA codeword allocation based on the superimposed DS matrix to obtain the superimposed DS matrix with embedded SCMA codebook.

[0122] Step 2.1: Assign a unique SCMA codebook to each user.

[0123] In this embodiment, assigning a unique SCMA codebook to each user is represented as follows:

[0124] ;

[0125] In the formula, This represents the superimposed DS matrix embedded with the SCMA codebook.

[0126] Step 2.2: Using the overload factor to constrain the number of data symbols, map the data symbols in the interleaved data sequence to the corresponding user's SCMA codebook to generate sparse multidimensional codewords.

[0127] Step 2.3: Overlay the sparse multidimensional codewords of all users to obtain the fused multi-user data. Superimposed codeword vectors.

[0128] Step 2.4: The superimposed codeword vectors are placed in the preset DS grid to obtain a superimposed DS matrix embedded in the SCMA codebook, as shown below. Figure 6As shown.

[0129] In this embodiment, the SCMA codebook is preset. The set of sparse codewords, the total number of data symbols transmitted on a single DS frame of the superimposed DS matrix is ​​represented as:

[0130] ;

[0131] In the formula, This represents the total number of data symbols transmitted on a single DS frame with the superimposed DS matrix. Denotes the delayed grid, where, and , This represents the modulo operation, which requires... It is an integer multiple of K. This indicates the maximum reference delay in the delay axis.

[0132] In this embodiment, the overload factor is expressed as:

[0133] ;

[0134] In the formula, Indicates the overload factor, typically, , among which, the The total number of data symbols that a user can transmit in the system is represented as:

[0135] ;

[0136] In the formula, Indicates the first The total number of data symbols that a user can transmit in the system, of which, The concatenated representation of the SCMA codebook is as follows:

[0137] , ;

[0138] In the formula, express Cascade of SCMA codebooks. Indicates the received number DS matrix of each user Indicates the first Each user is assigned the DS matrix corresponding to the first delay axis resource. Indicates the first Each user is assigned the DS matrix corresponding to the second delay axis resource. Indicates the first The user was assigned to the first The DS matrix corresponding to each delay axis resource This represents the superimposed SCMA codebook from all users.

[0139] Step 3: Perform WHT transformation on each row vector of the superimposed DS matrix with embedded SCMA codebook to obtain the DT matrix.

[0140] Step 3.1: Select a WHT matrix whose order matches the number of columns of the superimposed DS matrix of the embedded SCMA codebook.

[0141] Step 3.2: Use the WHT matrix to perform a WHT forward transform on each row vector of the superimposed DS matrix of the embedded SCMA codebook, and convert the sequence domain data into a DT matrix.

[0142] In this embodiment, the DT matrix is ​​represented as:

[0143] ;

[0144] In the formula, Represents the DT matrix. Represents the number of resources on the sequence axis. Perform WHT forward transform.

[0145] Step 4: Perform digital-to-analog conversion on the DT matrix to obtain a continuous time-domain signal and send it to the transmission channel.

[0146] Step 4.1: Traverse the DT matrix element by element according to the preset row priority or column priority order to convert the two-dimensional matrix DT data into a one-dimensional vector time-domain sample sequence.

[0147] Step 4.2: Perform digital-to-analog conversion on the one-dimensional vector-form time-domain sample sequence to obtain a continuous time-domain signal.

[0148] Step 4.3: Send the continuous time-domain signal to the transmission channel.

[0149] In this embodiment, the time-domain sample sequence is represented as:

[0150] ;

[0151] In the formula, Represents a time-domain sample sequence. Represents the DT matrix Vectorize it.

[0152] Step 5: Perform analog-to-digital conversion on the received continuous time-domain signal to obtain the reconstructed DT matrix.

[0153] Step 5.1: Perform analog-to-digital conversion on the received continuous time-domain signal to obtain a time-domain sample sequence in one-dimensional vector form.

[0154] Step 5.2: Perform element-wise inverse traversal of the one-dimensional vector form of the time-domain sample sequence according to the preset row priority or column priority order, and reconstruct the one-dimensional vector form of the time-domain sample data into a two-dimensional matrix DT matrix to obtain the reconstructed DT matrix.

[0155] In this embodiment, the reconstructed DT matrix is ​​represented as:

[0156] ;

[0157] In the formula, This represents the reconstructed DT matrix.

[0158] Step 6: Perform WHT inverse transformation on the reconstructed DT matrix to reconstruct each row vector of the superimposed DS matrix embedded in the SCMA codebook, and obtain the reconstructed superimposed DS matrix embedded in the SCMA codebook.

[0159] Step 6.1: Obtain the WHT inverse matrix or WHT matrix that has the same order as the transmitting end and matches the number of columns of the reconstructed DT matrix;

[0160] Step 6.2: Perform WHT inverse transformation on each row vector of the reconstructed DT matrix using the WHT inverse matrix pair or WHT matrix pair respectively, and convert and reconstruct the DT field data into each row vector of the superimposed DS matrix embedded with the SCMA codebook, to obtain the reconstructed superimposed DS matrix embedded with the SCMA codebook.

[0161] In this embodiment, the superimposed DS matrix of the reconstructed embedded SCMA codebook is represented as:

[0162] ;

[0163] In the formula, This represents the superimposed DS matrix of the reconstructed embedded SCMA codebook. This represents the inverse WHT transform.

[0164] Step 7: Perform SCMA decoding on each row vector of the superimposed DS matrix of the reconstructed embedded SCMA codebook to obtain the reconstructed superimposed DS matrix.

[0165] Step 7.1: The SCMA detector based on the message passing algorithm uses the effective factor matrix to separate the delay domain symbols corresponding to all users in each row of the superimposed DS matrix of the reconstructed embedded SCMA codebook through multi-user independent detection.

[0166] Step 7.2: Combine the time delay domain symbols corresponding to all users in each row according to user order to obtain the reconstructed superimposed DS matrix.

[0167] In this embodiment, the effective factor matrix is ​​represented as follows:

[0168] ;

[0169] In the formula, Represents the effective factor matrix, This represents the effective factor parameter corresponding to the first resource node. This represents the effective factor parameter corresponding to the second resource node. This represents the effective factor parameter corresponding to the 3rd resource node. Indicates the first The effective factor parameter corresponding to each resource node is 0, which indicates that the resource node has no SCMA codebook association with a certain user node.

[0170] Step 8: Split the reconstructed superimposed DS matrix and recover the bit sequences of multiple users through inverse DS grid mapping.

[0171] Step 8.1: Use the SCMA detector based on the message passing algorithm to perform multi-user separation on the reconstructed superimposed DS matrix to obtain the DS matrix of each user.

[0172] Step 8.2: Read the interleaved data sequence from each user's DS matrix in the reverse order of the DS grid mapping at the sending end.

[0173] Step 8.3: Read the DS matrix of each user in reverse order of filling the DS grid to obtain the interleaved data sequence of each user.

[0174] Step 8.4: Perform deinterleaving operation on the interleaved data sequence for each user to obtain the encoded sequence for each user.

[0175] Step 8.5: Use the channel decoder corresponding to the transmitter to decode the encoded sequence of each user to obtain the bit stream of each user.

[0176] Step 8.6: Convert the bit stream of each user from parallel to serial to recover the bit sequence of multiple users.

[0177] In summary, this invention, by performing WHT transformation on each row vector of the superimposed DS matrix embedded with the SCMA codebook to obtain the DT matrix, can effectively reduce the peak-to-average power ratio of the signal and improve the anti-interference performance of shortwave channel transmission. At the same time, by combining the features of DS grid mapping superposition and SCMA codeword allocation technology, it realizes efficient superposition and differentiation of multi-user signals on spectrum resources. Finally, through digital-to-analog conversion, a continuous time-domain signal is formed to complete reliable signal transmission in shortwave communication scenarios. This solves the problem that existing technologies cannot simultaneously overcome the peak-to-average power ratio of traditional OFDM systems, the high encoding and decoding complexity of existing SCMA-OFDM systems, and the interference caused by time-frequency dual-selective fading in shortwave channels in shortwave communication.

[0178] This invention obtains a reconstructed DT matrix by performing analog-to-digital conversion on the received continuous time-domain signal, and then reconstructs each row vector of the superimposed DS matrix embedded with the SCMA codebook through WHT inverse transform. Next, SCMA decoding is performed on each row vector of the reconstructed superimposed DS matrix embedded with the SCMA codebook to obtain a reconstructed superimposed DS matrix. Finally, the reconstructed superimposed DS matrix is ​​split and the bit sequences of multiple users are recovered through DS grid inverse mapping. This achieves efficient and accurate recovery of multi-user bit sequences, improving the reliability of OTSM-SCMA signal reception and multi-user separation capability in shortwave communication scenarios.

[0179] This invention achieves efficient superposition of multi-user signals in shortwave communication scenarios, low peak-to-average power ratio, and reliable transmission in the spectrum, significantly improving system spectral efficiency and anti-interference capability, while meeting the user data symbol transmission requirements under the constraints of total bandwidth and frame duration in OTSM systems. It also addresses the need for a unique SCMA codebook assigned to each user and the generation of sparse multidimensional codewords by using an overload factor to constrain the number of data symbols. The superimposed codewords are then embedded into the DS grid to obtain a superimposed DS matrix with embedded SCMA codebooks. A forward transformation is then performed on each row vector using a WHT matrix matching the column count to obtain a DT matrix. Finally, the DT matrix is ​​vectorized in row-priority order and converted from digital to analog to generate a continuous time-domain signal. This invention realizes efficient superposition of multi-user signals in the spectrum, low peak-to-average power ratio, and reliable transmission, significantly improving system spectral efficiency and anti-interference capability, while simultaneously meeting the user data symbol transmission requirements under the constraints of total bandwidth and frame duration in OTSM systems.

[0180] This invention achieves efficient and accurate recovery of multi-user bit sequences and improved anti-interference performance at the OTSM-SCMA signal receiver in shortwave communication scenarios by performing analog-to-digital conversion on the received continuous time-domain signal to obtain a one-dimensional vector time-domain sample sequence, and reconstructing it into a two-dimensional DT matrix according to a preset order. Combined with the WHT inverse matrix with the same order as the transmitter, the reconstructed DT matrix is ​​subjected to WHT inverse transformation to recover the row vectors of the superimposed DS matrix embedded with the SCMA codebook. Then, using the SCMA detector of the message passing algorithm and the effective factor matrix, the delay domain symbols are separated through multi-user independent detection and combined to reconstruct the superimposed DS matrix. Finally, the SCMA detector is used for multi-user separation, deinterleaving, channel decoding and parallel-to-serial conversion to recover the bit sequences of multiple users. This invention achieves efficient and accurate recovery of multi-user bit sequences and improved anti-interference performance at the OTSM-SCMA signal receiver in shortwave communication scenarios, significantly enhances multi-user separation capability and data recovery reliability, and meets the complete link requirements of DS grid inverse mapping and channel decoding.

[0181] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0182] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0183] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0184] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0185] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for transmitting OTSM-SCMA signals for shortwave communication, characterized in that, Executed by the sender, including: DS grid mapping is performed on the bit sequences of multiple users to be transmitted, and the grids are superimposed to form a superimposed DS matrix; SCMA codewords are allocated based on the superimposed DS matrix to obtain a superimposed DS matrix embedded in the SCMA codebook; Perform a WHT transformation on each row vector of the superimposed DS matrix of the embedded SCMA codebook to obtain the DT matrix; The DT matrix is ​​converted from digital to analog to obtain a continuous time-domain signal, which is then sent to the transmission channel.

2. The OTSM-SCMA signal transmission method for shortwave communication according to claim 1, characterized in that, Based on the user bit sequence to be transmitted, a DS grid mapping is performed to form a superimposed DS matrix, including: The bit sequences of multiple users to be transmitted are converted from serial to parallel to obtain a parallel bit stream of multiple users; The parallel bitstreams from the multiple users are encoded and interleaved to obtain the interleaved data sequence from the multiple users. The interleaved data sequences from the multiple users are filled into a preset DS grid to form a superimposed DS matrix; Where the total bandwidth and frame duration of the OTSM system are respectively and Then the superimposed DS matrix transmission User bits, Indicates frequency offset. The superimposed DS matrix represents the effective duration of the interleaved data sequence as follows: ； In the formula, This represents a superimposed DS matrix, which is a complex matrix with dimension n. The matrix, Indicates the first DS matrix of each user This represents the total number of users, where, Represents the field of complex numbers. Indicates the number of delay axis resources. This indicates the number of sequence axis resources.

3. The OTSM-SCMA signal transmission method for shortwave communication according to claim 1, characterized in that, SCMA codeword allocation is performed based on the superimposed DS matrix to obtain a superimposed DS matrix embedded in the SCMA codebook, including: Each user is assigned a unique SCMA codebook, represented as follows: ； In the formula, This represents a superimposed DS matrix embedded in the SCMA codebook; By using an overload factor to constrain the number of data symbols, the data symbols in the interleaved data sequence are mapped to the corresponding user's SCMA codebook to generate sparse multidimensional codewords. By overlaying the sparse multidimensional codewords of all users, we obtain the fused multi-user data. Superimposed codeword vectors; Will The superimposed codeword vectors are placed in the preset DS grid to obtain a superimposed DS matrix embedded in the SCMA codebook; The SCMA codebook is preset. The set of sparse codewords, the total number of data symbols transmitted on a single DS frame of the superimposed DS matrix is ​​represented as: ； In the formula, This represents the total number of data symbols transmitted on a single DS frame with the superimposed DS matrix. Denotes the delayed grid, where, and , This represents the modulo operation, which requires... It is an integer multiple of K. Indicates the maximum reference delay number in the delay axis; The overload factor is expressed as: ； In the formula, Indicates the overload factor, typically, , among which, the The total number of data symbols that a user can transmit in the system is represented as: ； In the formula, Indicates the first The total number of data symbols that a user can transmit in the system, of which, The concatenated representation of the SCMA codebook is as follows: ， ； In the formula, express Cascade of SCMA codebooks. Indicates the received number DS matrix of each user Indicates the first Each user is assigned the DS matrix corresponding to the first delay axis resource. Indicates the first Each user is assigned the DS matrix corresponding to the second delay axis resource. Indicates the first The user was assigned to the first The DS matrix corresponding to each delay axis resource This represents the superimposed SCMA codebook from all users.

4. The OTSM-SCMA signal transmission method for shortwave communication according to claim 1, characterized in that, Perform a WHT transformation on each row vector of the superimposed DS matrix containing the embedded SCMA codebook to obtain the DT matrix, including: Select a WHT matrix whose order matches the number of columns of the superimposed DS matrix of the embedded SCMA codebook; The WHT forward transform is performed on each row vector of the superimposed DS matrix embedded in the SCMA codebook using the WHT matrix to convert the sequence domain data into a DT matrix. The DT matrix is ​​represented as follows: ； In the formula, Represents the DT matrix. Represents the number of resources on the sequence axis. Perform WHT forward transform.

5. The OTSM-SCMA signal transmission method for shortwave communication according to claim 1, characterized in that, The process of performing digital-to-analog conversion on the DT matrix to obtain a continuous time-domain signal and transmitting it to the transmission channel includes: The DT matrix is ​​traversed element by element according to a preset row priority or column priority order, and the two-dimensional matrix DT data is converted into a one-dimensional vector time-domain sample sequence. The one-dimensional vector-form time-domain sample sequence is converted from digital to analog to obtain a continuous time-domain signal; Send continuous time-domain signals to the transmission channel; The time-domain sample sequence is represented as follows: ； In the formula, Represents a time-domain sample sequence. Represents the DT matrix Vectorize it.

6. A method for receiving OTSM-SCMA signals for shortwave communication, executed by the receiving end, characterized in that, include: The received continuous time-domain signal is converted from analog to digital to obtain the reconstructed DT matrix; The reconstructed DT matrix is ​​subjected to the WHT inverse transformation to reconstruct each row vector of the superimposed DS matrix embedded in the SCMA codebook, thus obtaining the reconstructed superimposed DS matrix embedded in the SCMA codebook. SCMA decoding is performed on each row vector of the superimposed DS matrix of the reconstructed embedded SCMA codebook to obtain the reconstructed superimposed DS matrix. The reconstructed superimposed DS matrix is ​​split and the bit sequences of multiple users are recovered by inverse mapping of the DS grid; The continuous time-domain signal is obtained by the OTSM-SCMA signal transmission method for shortwave communication as described in any one of claims 1-5.

7. The OTSM-SCMA signal receiving method for shortwave communication according to claim 6, characterized in that, The received continuous time-domain signal is converted from analog to digital to obtain the reconstructed DT matrix, including: The received continuous time-domain signal is converted from analog to digital to obtain a time-domain sample sequence in one-dimensional vector form; The time-domain sample sequence in one-dimensional vector form is traversed element-wise in reverse order according to the preset row priority or column priority order. The time-domain sample data in one-dimensional vector form is reconstructed into a two-dimensional matrix DT matrix, and the reconstructed DT matrix is ​​obtained. The reconstructed DT matrix is ​​represented as follows: ； In the formula, This represents the reconstructed DT matrix.

8. The OTSM-SCMA signal receiving method for shortwave communication according to claim 6, characterized in that, The reconstructed DT matrix is ​​subjected to an inverse WHT transform to obtain each row vector of the superimposed DS matrix of the reconstructed SCMA codebook, including: The WHT inverse matrix or WHT matrix that has the same order as the transmitting end and matches the number of columns of the reconstructed DT matrix; By performing the WHT inverse transformation on each row vector of the reconstructed DT matrix using the WHT inverse matrix pair or the WHT matrix, the DT field data is transformed and reconstructed into each row vector of the superimposed DS matrix embedded in the SCMA codebook, thus obtaining the reconstructed superimposed DS matrix embedded in the SCMA codebook. The superimposed DS matrix of the reconstructed embedded SCMA codebook is represented as follows: ； In the formula, This represents the superimposed DS matrix of the reconstructed embedded SCMA codebook. This represents the inverse WHT transform.

9. The OTSM-SCMA signal receiving method for shortwave communication according to claim 6, characterized in that, SCMA decoding is performed on each row vector of the superimposed DS matrix of the reconstructed embedded SCMA codebook to obtain the reconstructed superimposed DS matrix, including: The SCMA detector based on the message passing algorithm uses the effective factor matrix to separate the time-delay domain symbols of all users in each row of the superimposed DS matrix of the reconstructed embedded SCMA codebook through multi-user independent detection. The time delay domain symbols corresponding to all users in each row are combined in user order to obtain the reconstructed superimposed DS matrix; The effective factor matrix is ​​represented as follows: ； In the formula, Represents the effective factor matrix, This represents the effective factor parameter corresponding to the first resource node. This represents the effective factor parameter corresponding to the second resource node. This represents the effective factor parameter corresponding to the 3rd resource node. Indicates the first The effective factor parameter corresponding to each resource node is 0, which indicates that the resource node has no SCMA codebook association with a certain user node.

10. The OTSM-SCMA signal receiving method for shortwave communication according to claim 6, characterized in that, The reconstructed superimposed DS matrix is ​​split and the bit sequences of multiple users are recovered through inverse DS grid mapping, including: The reconstructed superimposed DS matrix is ​​separated into multiple users using an SCMA detector based on a message passing algorithm to obtain the DS matrix for each user. The interleaved data sequence is read from each user's DS matrix in the reverse order of the DS grid mapping at the sending end; The interleaved data sequence for each user is obtained by reading the DS matrix of each user in reverse order of filling the DS grid; Perform deinterleaving on the interleaved data sequence for each user to obtain the encoded sequence for each user; The encoded sequence of each user is decoded using a channel decoder corresponding to the transmitting end to obtain the bit stream of each user; the bit stream of each user is then converted from parallel to serial to recover the bit sequence of multiple users.

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