High-dimensional index modulation OTFS implementation method and system based on wavelet transform

Abstract

The present application provides a method and system for implementing high-dimensional index modulation (OTFS) based on wavelet transform, which relates to the field of wireless communications. The method includes: using a high-dimensional signal constellation diagram to complete single-mode index modulation mapping or dual-mode index modulation mapping to construct a delay-Doppler domain OTFS signal; using Mallat wavelet transform technology to complete the modulation of the delay-Doppler domain OTFS signal to obtain a two-dimensional time-domain OTFS signal; vectorizing the two-dimensional time-domain OTFS signal, adding a cyclic prefix, and transmitting it into a time-varying channel for transmission to realize a high-dimensional OTFS system based on wavelet transform. The present invention uses wavelet transform to replace traditional Fourier transform, thereby improving system reliability and reducing system complexity. The introduction of index modulation improves spectrum efficiency, better adapts to future communication needs, and solves the technical problem that high-dimensional constellation diagrams improve system reliability but lose spectrum efficiency.

Description

Technical Field

[0001] The present application relates to the field of wireless communications, and in particular to a method and system for implementing high-dimensional index modulation (OTFS) based on wavelet transform. Background Art

[0002] Some traditional orthogonal time-frequency-space (OTFS) modulation systems are described in References 1, 2, and 3. The dual-mode index modulation OTFS system described in Reference 1 uses dual-mode index modulation to transmit information, improving the system's bit error rate performance and spectral efficiency compared to traditional non-index modulation OTFS systems. The dual-mode index modulation OTFS system in Reference 1 uses a two-dimensional signal constellation to carry bit information, but does not consider the advantages of higher-dimensional signal constellations in terms of minimum Euclidean distance (MED). For example, three-, four-, or higher-dimensional constellations can provide higher MED values ​​than corresponding two-dimensional signal constellations while maintaining the same average power.

[0003] Given the advantages of high-dimensional signal constellations, Reference 2 introduces an OTFS system based on a three-dimensional signal constellation. Information bits are mapped to signal points in the three-dimensional constellation to obtain an OTFS signal in the delay-Doppler domain. The OTFS signal is then modulated using the inverse symplectic finite Fourier transform and Heisenberg transform based on Fourier transform technology and converted to the time domain. The system has high reliability, but its spectral efficiency decreases as the transmission bandwidth increases.

[0004] To improve the reliability of the OTFS system, Reference 3 proposed an OTFS system based on wavelet transform. Compared with the Fourier transform, the wavelet transform captures the local details and global characteristics of the signal by providing localized information in both time and frequency dimensions. The time-frequency domain localization characteristics of the wavelet transform are more adaptable to time-varying channels, improving the reliability of the system and reducing its complexity.

[0005] Document 1: H.Zhao, D.He, Z.Kang, and H.Wang, "Orthogonal time frequency space (OTFS) with dual-mode index modulation," IEEE Wireless Commun.Lett., vol.10, no.5, pp.991–995, May 2021.

[0006] Document 2: Y.Chen, L.Zhao, Y.Jiang, W.Li, H.Gao, and C.Liu, "OTFS waveform based 3-D signal constellation for time-variant channels," IEEE Commun.Lett., vol.27, no.8, pp.1999–2003, Aug.2023.

[0007] Document 3: MHAbid, IATalin and MIKadir, "Wavelet-Aided OTFS for RIS-Assisted High-Mobility Wireless Channels," IEEE Wireless Commun. Lett., vol.13, no.6, pp.1611-1615, Jun.2024. Summary of the Invention

[0008] The purpose of the present invention is to provide a method and system for realizing high-dimensional index modulation OTFS based on wavelet transform in order to solve the problem of low spectrum efficiency of existing high-dimensional OTFS systems.

[0009] The above-mentioned purpose of this application is achieved through the following technical solutions:

[0010] S1: Use the high-dimensional signal constellation to complete single-mode index modulation mapping or dual-mode index modulation mapping to construct the delay-Doppler domain OTFS signal;

[0011] S2: Use Mallat wavelet transform technology to complete the modulation of the delay-Doppler domain OTFS signal to obtain a two-dimensional time domain OTFS signal;

[0012] S3: The two-dimensional time-domain OTFS signal is vectorized and a cyclic prefix is ​​added to the signal before it is transmitted into the time-varying channel, thus realizing a high-dimensional OTFS system based on wavelet transform.

[0013] Optionally, step S1 includes:

[0014] Each OTFS signal frame sends c information bits, which are mapped to a two-dimensional matrix of M0×N0 through a high-dimensional signal constellation. The c bits are divided into G groups by the bit grouper module, and each group contains p=c / G bits, where G=M0×N0 / V, M0×N0 also represents the grid size of a frame of delay-Doppler domain OTFS signal, and V represents the number of subcarriers in each OTFS signal subframe, that is, each grid maps a complex signal;

[0015] In a high-dimensional signal constellation of size M, a D-dimensional signal is represented as a column vector S D =(W1,W2,…,W d ,…W D ), T , 1 ≤ d ≤ D, T represents the transpose operation, and the coordinate components of all symbols in the high-dimensional signal constellation are non-zero real numbers.

[0016] Optionally, step S1 further includes:

[0017] The steps to complete single-mode index modulation mapping using the high-dimensional signal constellation are as follows:

[0018] In the g-th sub-frame of any frame of OTFS signal, 1 ≤ g ≤ G, divide the p bits in each sub-frame into p1 bits and p2 bits, that is, p = p1 + p2, p1 is the index bit, which determines the activated sub-carrier position, and p2 represents the number of bits carried by a high-dimensional signal, that is, each sub-frame maps a high-dimensional symbol;

[0019] In the formula[[ID=H22]] represents the floor function, that is, rounding down, is the binomial coefficient, D < V, that is, D of the V sub-carriers in the sub-frame are activated for mapping the high-dimensional signal coordinate elements, and the positions of the unactivated V - D sub-carriers are 0;

[0020] The indexes of the activated sub-carriers are represented as I = [I1, I2, …, I D ;

[0021] p2 = log2M is the number of bits contained in a high-dimensional signal, that is, the symbol bits in a sub-frame;

[0022] The mapped sub-frame is represented as U g = [W1(I1), W2(I2), …, W T D (I D )];

[0023] Concatenate all G sub-frames to construct a two-dimensional matrix M0×N0, that is, an OTFS signal X in the time-delay - Doppler domain DD .

[0024] Optionally, step S1 further includes:

[0025] The steps to complete dual-mode index modulation mapping using the high-dimensional signal constellation are as follows:

[0026] In the g-th sub-frame of any frame of OTFS signal, 1 ≤ g ≤ G, set a two-dimensional real matrix X of D×n for mapping n high-dimensional signals, that is, each column maps a high-dimensional signal;

[0027] The p bits in each subframe are divided into p1 bits and p2 bits, that is, p = p1 + p2, where p1 is the index bit that determines the activation position, and p2 represents the total number of bits carried by the n high-dimensional signals;

[0028] The K columns in n columns have size M A Constellation diagram S A Mapping, that is The activated position index is represented by I A =[I A，1 ,I A，2 ,…,I A，K ], the mapped signal is represented by U A =[S A (I A，1 ),…,S A (I A，K )];

[0029] The other n–K columns in the n columns use size M B Constellation diagram S B Mapping is performed, and the mapped signal is represented as U B =[S B (I B，1 ),…,S B (I B，n-K )], where the index position is represented by I B =[I B，1 ,I B，2 ,…,I B，n-K ];

[0030] p2=K log2M A +(n–K)log2M B is the number of symbol bits in a subframe;

[0031] The two-dimensional matrix after mapping is expressed as X=[U A ,U B ];

[0032] By in-phase conversion or orthogonal conversion, each two adjacent real groups in the matrix X are combined into a complex signal; the subframe after in-phase conversion or orthogonal conversion is represented as U g =[X1,X2,…,X V ], 1≤v≤V, V represents the number of complex signals in the subcarrier; the number of complex signals in the reorganized subframe is V=D×n / 2;

[0033] Concatenate all G subframes to construct a M0×N0 two-dimensional matrix, i.e., an OTFS signal X in the delay-Doppler domain. DD .

[0034] Optionally, step S2 includes:

[0035] S21: Calculate the coefficients of the wavelet transform matrix;

[0036] Wavelet transform is achieved by scaling function φ(x) and wavelet transform coefficients The main information and detailed information of the OTFS signal in the delay-Doppler domain are expressed as follows:

[0037]

[0038] In the formula, the coefficient c k The constraints are

[0039] S22: Construct wavelet transform matrix W N ;

[0040] S23: Two-dimensional signal matrix X of the OTFS signal in the delay-Doppler domain DD Each row of the DWT transform and each column of the IDWT transform are performed to convert the delay-Doppler domain signal into the time-frequency domain signal X TF ,as follows:

[0041]

[0042] Where H represents the complex conjugate transpose; Represents the wavelet transform matrix with dimension M0; Represents the complex conjugate transposed matrix of the wavelet transform matrix with dimension N0;

[0043] S24: To X TF Perform DWT transformation on each column to obtain the two-dimensional time domain OTFS signal x T ,Right now

[0044]

[0045] A high-dimensional index modulation (OTFS) implementation system based on wavelet transform, the system comprising: a transmitting end and a receiving end;

[0046] The transmitter includes: a bit grouper module, an OTFS subframe generator module, an OTFS frame generator module, a discrete wavelet transform module, an inverse discrete wavelet transform module, and a cyclic prefix module; each OTFS subframe generator includes: an index selector module and a high-dimensional signal mapper module;

[0047] The receiving end includes: a cyclic prefix removal module, a DWT module, an IDWT module, a minimum mean square error equalizer and maximum likelihood detection module, an OTFS subframe demodulator module, and a bit generator module; each OTFS subframe demodulator includes: an index detector module and a high-dimensional signal demapper module.

[0048] An electronic device includes a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device performs a high-dimensional index modulation (OTFS) implementation method based on wavelet transform.

[0049] A computer-readable storage medium stores instructions. When the instructions are executed, a method for realizing high-dimensional index modulation (OTFS) based on wavelet transform is executed.

[0050] The beneficial effects of the technical solution provided by this application are:

[0051] 1. The present invention uses wavelet transform to replace the traditional Fourier transform. The time-frequency domain localization characteristics of wavelet transform are more adaptable to time-varying channels, improving the reliability of the system. The wavelet transform matrix is ​​sparse, which reduces the implementation complexity of the system. Moreover, the more information the high-order signal carries, the more signal details can be extracted using the wavelet transform, and the better the performance obtained. Mallat wavelet transform technology is applied to the high-dimensional OTFS signal based on index modulation for modulation, which reduces the implementation complexity of the system and further improves the system performance.

[0052] 2. Compared with the traditional three-dimensional OTFS system, this invention applies high-dimensional index modulation technology to the OTFS system for the first time. Index modulation technology improves the spectrum efficiency. At the same time, the high-dimensional signal improves the reliability of the system. The high-dimensional index modulation OTFS system is more adaptable to future communication needs.

[0053] 3. Compared with the corresponding two-dimensional signal constellation diagram, the high-dimensional signal constellation diagram of the present invention has a larger MED. Compared with some traditional index modulation OTFS systems, the larger constellation diagram MED enables the system of the present invention to achieve better system bit error rate performance, which is conducive to meeting the requirements for high-quality communication in time-varying channel environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present application will be further described below with reference to the accompanying drawings and embodiments, in which:

[0055] Figure 1 It is a step diagram in the embodiment of the present application;

[0056] Figure 2This is a structural diagram of the high-dimensional OTFS system sending end in an embodiment of the present application;

[0057] Figure 3 This is a structural diagram of a high-dimensional OTFS system receiving end in an embodiment of the present application;

[0058] Figure 4 is a comparison chart of system bit error rate performance in an embodiment of the present application;

[0059] Figure 5 It is a schematic diagram of the structure of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0060] In order to have a clearer understanding of the technical features, purposes and effects of this application, the specific implementation methods of this application are now described in detail with reference to the accompanying drawings.

[0061] The embodiments of the present application provide a method for implementing high-dimensional index modulation (OTFS) based on wavelet transform.

[0062] Please refer to Figure 1 , Figure 1 This is a step diagram of a method for implementing high-dimensional index modulation (OTFS) based on wavelet transform in an embodiment of the present application, including:

[0063] S1: Use the high-dimensional signal constellation to complete single-mode index modulation mapping or dual-mode index modulation mapping to construct the delay-Doppler domain OTFS signal;

[0064] S2: Use Mallat wavelet transform technology to complete the modulation of the delay-Doppler domain OTFS signal to obtain a two-dimensional time domain OTFS signal;

[0065] S3: The two-dimensional time-domain OTFS signal is vectorized and a cyclic prefix is ​​added to the signal before it is transmitted into the time-varying channel, thus realizing a high-dimensional OTFS system based on wavelet transform.

[0066] Step S1 includes:

[0067] Each OTFS signal frame sends c information bits, which are mapped to a two-dimensional matrix of M0×N0 through a high-dimensional signal constellation. The c bits are divided into G groups by the bit grouper module, and each group contains p=c / G bits, where G=M0×N0 / V, M0×N0 also represents the grid size of a frame of delay-Doppler domain OTFS signal, and V represents the number of subcarriers in each OTFS signal subframe, that is, each grid maps a complex signal;

[0068] In a high-dimensional signal constellation diagram of size M, a D-dimensional signal is represented as a column vector S D =(W1,W2,…,W d ,…W D )T , where \(1\leq d\leq D\), \(T\) represents the transpose operation, and the coordinate components of all symbols in the high-dimensional signal constellation are non-zero real numbers.

[0069] Step S1 further includes:

[0070] The steps of completing single-mode index modulation mapping using the high-dimensional signal constellation are as follows:

[0071] In the \(g\)th sub-frame of any frame of OTFS signals, where \(1\leq g\leq G\), the \(p\) bits in each sub-frame are divided into \(p1\) bits and \(p2\) bits, that is, \(p = p1 + p2\). \(p1\) is the index bit, which determines the position of the activated sub-carrier, and \(p2\) represents the number of bits carried by a high-dimensional signal, that is, each sub-frame maps a high-dimensional symbol;

[0072] [[ID=1३]] »In the formula represents the floor function, that is, rounding down, is the binomial coefficient, \(D < V\), that is, \(D\) of the \(V\) sub-carriers in the sub-frame are activated for mapping the high-dimensional signal coordinate elements, and the positions of the unactivated \(V - D\) sub-carriers are 0;

[0073] [[ID=2१]]The index of the activated sub-carrier is represented as \(I=[I1, I2, \cdots, I D [[ID=2३]]];

[0074] \(p2=\log2M\) is the number of bits contained in a high-dimensional signal, that is, the symbol bits in a sub-frame;

[0075] The mapped sub-frame is represented as \(U g =[W1(I1), W2(I2), \cdots, W D [[ID=3३]](I[[ID=३4]] D )];

[0076] [[ID=३८]]All the \(G\) sub-frames are concatenated to construct a two-dimensional matrix \(M0\times N0\), that is, an OTFS signal \(X\) in the time-delay - Doppler domain DD .

[0077] An embodiment provided by this application is as follows. For example, when \(V = 4\) and \(D = 3\), the implementation of a high-dimensional index modulation OTFS sub-frame based on wavelet transform is shown in Table I:

[0078] Table I

[0079]

[0080] When \(p1 = [0 0]\), the mapped two-dimensional matrix is represented as:

[0081] U g =[W1, W2, W3, 0] (4)

[0082] Step S1 further includes:

[0083] The steps to complete dual-mode index modulation mapping using a high-dimensional signal constellation are as follows:

[0084] In the g-th subframe of any OTFS signal, 1≤g≤G, a D×n two-dimensional real matrix X is assumed to be used to map n high-dimensional signals, that is, each column maps a high-dimensional signal;

[0085] The p bits in each subframe are divided into p1 bits and p2 bits, that is, p = p1 + p2, where p1 is the index bit that determines the activation position, and p2 represents the total number of bits carried by the n high-dimensional signals;

[0086] The K columns in n columns have size M A Constellation diagram S A Mapping, that is The activation position index is denoted as I A =[I A ,1,I A ,2,…,I A , K ], the mapped signal is represented by U A =[S A (I A ,1),…,S A (I A , K )];

[0087] The other n–K columns in the n columns use size M B Constellation diagram S B Mapping is performed, and the mapped signal is represented as U B =[S B (I B，1 ),…,S B (I B，n-K )], where the index position is represented by I B =[I B，1 ,I B，2 ,…,I B，n-K ];

[0088] p2=K log2M A +(n–K)log2M B is the number of symbol bits in a subframe;

[0089] The two-dimensional matrix after mapping is expressed as X=[U A ,U B ];

[0090] By in-phase conversion or orthogonal conversion, each two adjacent real groups in the matrix X are combined into a complex signal; the subframe after in-phase conversion or orthogonal conversion is represented as U g=[X1,X2,…,X V ], 1≤v≤V, V represents the number of complex signals in the subcarrier; the number of complex signals in the reorganized subframe is V=D×n / 2;

[0091] Concatenate all G subframes to construct a M0×N0 two-dimensional matrix, i.e., an OTFS signal X in the delay-Doppler domain. DD .

[0092] As an embodiment, for example, when n=4, K=2, and D=3, a high-dimensional index modulation OTFS subframe based on wavelet transform is implemented as shown in Table II:

[0093] Table II

[0094]

[0095]

[0096] When p1 = [0 0], the mapped two-dimensional matrix is ​​expressed as

[0097]

[0098] The subframe after in-phase / quadrature conversion is expressed as:

[0099]

[0100] Step S2 includes:

[0101] S21: Calculate the coefficients of the wavelet transform matrix;

[0102] Wavelet transform is achieved by scaling function φ(x) and wavelet transform coefficients The main information and detailed information of the OTFS signal in the delay-Doppler domain are expressed as follows:

[0103]

[0104] In the formula, the coefficient c k The constraints are

[0105] S22: Construct wavelet transform matrix W N ;

[0106] As an embodiment, the wavelet transform technology is used instead of the traditional Fourier transform to improve the system performance and reduce the implementation complexity.

[0107] As an example, according to the Mallat wavelet decomposition algorithm, the signal decomposition process is divided into two steps: filtering and downsampling. The wavelet transform matrix is ​​composed of a high-pass filter and a low-pass filter, and downsampling by two units is performed by circular shift. In order to recover the information conveyed by the signal, the wavelet transform matrix must have orthogonality. The Mallat algorithm is mainly used for multiresolution analysis (MRA) of wavelet transform.

[0108] S23: Two-dimensional signal matrix X of the OTFS signal in the delay-Doppler domain DD Each row of the DWT transform and each column of the IDWT transform are performed to convert the delay-Doppler domain signal into the time-frequency domain signal X TF ,as follows:

[0109]

[0110] Where H represents the complex conjugate transpose; Represents the wavelet transform matrix with dimension M0; Represents the complex conjugate transposed matrix of the wavelet transform matrix with dimension N0;

[0111] S24: To X TF Perform DWT transformation on each column to obtain the two-dimensional time domain OTFS signal x T ,Right now

[0112]

[0113] As an example, when the wavelet length is 4 and the matrix dimension is N, the wavelet transform matrix W N Expressed as:

[0114]

[0115] At this time, the inverse wavelet transform matrix Expressed as

[0116]

[0117] By choosing different wavelet bases, different coefficients c are calculated. k , different wavelet transform matrices can be obtained.

[0118] As an embodiment, when Haar wavelet is used, k=2, and the coefficient matrix C is calculated using formula (1). Haar It can be expressed as C Haar =[c0,c1]=

[11] . When Daubechies wavelet is used, k=4. After calculation, the coefficient matrix C D4Represented as C D4 =[c0,c1,c2,c3]=[0.6830,1.1830,0.3170,-0.1830].

[0119] A high-dimensional index modulation (OTFS) implementation system based on wavelet transform, the system comprising: a transmitting end and a receiving end;

[0120] The transmitter includes: a bit grouper module, an OTFS subframe generator module, an OTFS frame generator module, a discrete wavelet transform module, an inverse discrete wavelet transform module, and a cyclic prefix module; each OTFS subframe generator includes: an index selector module and a high-dimensional signal mapper module;

[0121] The receiving end includes: a cyclic prefix removal module, a DWT module, an IDWT module, a minimum mean square error equalizer and maximum likelihood detection module, an OTFS subframe demodulator module, and a bit generator module; each OTFS subframe demodulator includes: an index detector module and a high-dimensional signal demapper module.

[0122] As an example, as an example, refer to Figure 2 The high-dimensional OTFS system transmitter based on wavelet transform includes: a bit grouper module, an OTFS subframe generator module, an OTFS frame generator module, a discrete wavelet transform (DWT) module, an inverse discrete wavelet transform (IDWT) module, and a cyclic prefix module; each OTFS subframe generator includes: an index selector module and a high-dimensional signal mapper module. Figure 3 The receiving end of the high-dimensional OTFS system based on wavelet transform includes a cyclic prefix removal module, a DWT module, an IDWT module, a minimum mean square error (MMSE) equalizer and maximum likelihood (ML) detection module, an OTFS subframe demodulator module, and a bit generator module. Each OTFS subframe demodulator includes an index detector module and a high-dimensional signal demapper module. This combined high-dimensional OTFS system based on wavelet transform is used to transmit digital signals, improving the efficiency and reliability of information transmission.

[0123] This application provides an example as follows:

[0124] In a high-dimensional OTFS system based on wavelet transform of the present invention, a wavelet transform matrix based on Haar wavelet is applied, and a three-dimensional quaternary signal constellation is adopted. Modulation scheme II (using a high-dimensional signal constellation to complete dual-mode index modulation mapping) is adopted, that is, M A =M B=4, D=3, and the coordinates of all symbols are shown in Table III. Other parameters are as follows: M0=N0=8, n=4, K=2, V=6, G=16. The mapping relationship is shown in Table I. The channel environment is a time-varying channel, the number of paths in the multipath channel is 4, and the Doppler tap and delay tap are [0 1 2 3]. The transmitter sends 10 5 Frame OTFS signal, used for bit error rate statistics at the receiving end.

[0125] Table III

[0126]

[0127] Table IV

[0128]

[0129] Computer simulation results are as follows Figure 4 As shown, reference 1 adopts dual-mode index modulation, mapping scheme A adopts QPSK modulation, mapping scheme B adopts BPSK modulation, V=4, and 2 subcarriers are activated in each OTFS subframe; reference 2 adopts a three-dimensional quaternary signal constellation diagram, whose coordinates are shown in Table IV, and has the same MED as the three-dimensional quaternary signal constellation diagram adopted by the present invention; reference 3 adopts the same three-dimensional quaternary signal constellation diagram as reference 2, and uses the wavelet transform matrix of the Haar wavelet basis instead of the Fourier transform matrix.

[0130] When the proposed solution II is adopted, the system spectrum efficiency can be calculated as follows:

[0131]

[0132] For mapping scheme II and other high-dimensional OTFS systems, when a square OTFS grid is used, let G = 16, n = 4, is the total number of OTFS grid cells during actual transmission, L ZP The number of zero-filled grids required to generate a square OTFS grid. Indicates rounding up. Based on this example, the spectrum efficiency can be calculated as follows

[0133]

[0134] Similarly, we can calculate that the spectrum efficiency of document 1 is 1.5 bits / s / Hz, and the spectrum efficiency of documents 2 and 3 is 1.28 bits / s / Hz. Figure 3 It can be seen that the system of the present invention has the best reliability and higher spectrum efficiency.

[0135] The key technical points of the present invention are:

[0136] (1) The present invention applies high-dimensional index modulation technology to the OTFS system. The index modulation technology improves the spectrum efficiency of the system. At the same time, the high-dimensional signal improves the reliability of the system. The high-dimensional index modulation OTFS system is more adaptable to future communication needs.

[0137] (2) The present invention applies Mallat wavelet transform technology to modulate the high-dimensional OTFS signal based on index modulation, which reduces the implementation complexity of the system and further improves the system performance.

[0138] This application also discloses an electronic device. Figure 5 , Figure 5 Schematic diagram of the structure of an electronic device disclosed in an embodiment of the present application. The electronic device 500 may include: at least one processor 501, at least one network interface 504, a user interface 503, a memory 505, and at least one communication bus 502.

[0139] The communication bus 502 is used to implement the connection and communication between these components.

[0140] The user interface 503 may include a display screen, and the optional user interface 503 may also include a standard wired interface or a wireless interface.

[0141] The network interface 504 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0142] The present application also discloses a computer-readable storage medium storing a plurality of instructions suitable for loading by a processor to execute the above-mentioned high-dimensional index modulation (OTFS) implementation method based on wavelet transform.

[0143] The above are merely exemplary embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. In other words, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure.

[0144] This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not described herein. The description and examples are to be considered as exemplary only, and the scope and spirit of the present disclosure are to be defined by the claims.

Claims

1. A method for implementing high-dimensional index modulation (OTFS) based on wavelet transform, characterized in that: The method comprises the following steps: S1: Use the high-dimensional signal constellation to complete single-mode index modulation mapping or dual-mode index modulation mapping to construct the delay-Doppler domain OTFS signal; S2: Use Mallat wavelet transform technology to complete the modulation of the delay-Doppler domain OTFS signal to obtain a two-dimensional time domain OTFS signal; S3: The two-dimensional time-domain OTFS signal is vectorized and a cyclic prefix is ​​added to the signal before it is transmitted into the time-varying channel to realize a high-dimensional OTFS system based on wavelet transform.

2. The method for implementing high-dimensional index modulation (OTFS) based on wavelet transform according to claim 1, wherein: Step S1 includes: Each OTFS signal frame sends c information bits, which are mapped to a two-dimensional matrix of M0×N0 through a high-dimensional signal constellation. The c bits are divided into G groups by the bit grouper module, and each group contains p=c / G bits, where G=M0×N0 / V, M0×N0 also represents the grid size of a frame of delay-Doppler domain OTFS signal, and V represents the number of subcarriers in each OTFS signal subframe, that is, each grid maps a complex signal; In a high-dimensional signal constellation diagram of size M, a D-dimensional signal is represented as a column vector S D =(W1,W2,…,W d ,…W D ) T , 1≤d≤D, T represents a transpose operation, and the coordinate components of all symbols in the high-dimensional signal constellation are non-zero real numbers.

3. The method for implementing high-dimensional index modulation (OTFS) based on wavelet transform according to claim 2, wherein: Step S1 further includes: The steps to complete single-mode index modulation mapping using a high-dimensional signal constellation are as follows: In the g-th subframe of any OTFS signal, 1≤g≤G, the p bits in each subframe are divided into p1 bits and p2 bits, that is, p=p1+p2, where p1 is the index bit that determines the activated subcarrier position, and p2 represents the number of bits carried by a high-dimensional signal, that is, each subframe maps a high-dimensional symbol; In the formula represents the floor function, that is, rounding down, is the binomial coefficient, D < V, that is, D out of V subcarriers in a subframe are activated for mapping high-dimensional signal coordinate elements, and the positions of the V - D unactivated subcarriers are 0; The activated subcarrier index is represented as I = [I1, I2, ..., I D ]; p2=log2M is the number of bits contained in a high-dimensional signal, that is, the number of symbol bits in a subframe; The mapped subframe is represented as U g =[W1(I1),W2(I2),…,W D (I D )]; Concatenate all G subframes to construct a M0×N0 two-dimensional matrix, i.e., an OTFS signal X in the delay-Doppler domain. DD .

4. The method for implementing high-dimensional index modulation (OTFS) based on wavelet transform according to claim 2, wherein: Step S1 further includes: The steps to complete dual-mode index modulation mapping using a high-dimensional signal constellation are as follows: In the g-th subframe of any OTFS signal, 1≤g≤G, a D×n two-dimensional real matrix X is assumed to be used to map n high-dimensional signals, that is, each column maps a high-dimensional signal; The p bits in each subframe are divided into p1 bits and p2 bits, that is, p = p1 + p2, where p1 is the index bit that determines the activation position, and p2 represents the total number of bits carried by the n high-dimensional signals; The K columns in n columns have size M A Constellation diagram S A Mapping, that is The activation position index is denoted as I A =[I A，1 ,I A，2 ,…,I A，K ], the mapped signal is represented by U A =[S A (I A，1 ),…,S A (I A，K )]; The other n–K columns in the n columns use size M B Constellation diagram S B Mapping is performed, and the mapped signal is represented as U B =[S B (I B，1 ),…,S B (I B，n-K )], where the index position is represented by I B =[I B，1 ,I B，2 ,…,I B，n-K ]; p2=K log2M A +(n–K)log2M B is the number of symbol bits in a subframe; The two-dimensional matrix after mapping is expressed as X=[U A ,U B ]; By in-phase conversion or orthogonal conversion, each two adjacent real groups in the matrix X are combined into a complex signal; the subframe after in-phase conversion or orthogonal conversion is represented as U g =[X1,X2,…,X V ], 1≤v≤V, V represents the number of complex signals in the subcarrier; the number of complex signals in the reorganized subframe is V=D×n / 2; Concatenate all G subframes to construct a M0×N0 two-dimensional matrix, i.e., an OTFS signal X in the delay-Doppler domain. DD .

5. The method for implementing high-dimensional index modulation (OTFS) based on wavelet transform according to claim 4, characterized in that: Step S2 includes: S21: Calculate the coefficients of the wavelet transform matrix; Wavelet transform is achieved by scaling function φ(x) and wavelet transform coefficients The main information and detailed information of the OTFS signal in the delay-Doppler domain are expressed as follows: In the formula, the coefficient c k The constraints are S22: Construct wavelet transform matrix W N ; S23: Two-dimensional signal matrix X of the OTFS signal in the delay-Doppler domain DD Each row of the DWT transform and each column of the IDWT transform are performed to convert the delay-Doppler domain signal into the time-frequency domain signal X TF ,as follows: Where H represents the complex conjugate transpose; Represents the wavelet transform matrix with dimension M0; Represents the complex conjugate transposed matrix of the wavelet transform matrix with dimension N0; S24: To X TF Perform DWT transformation on each column to obtain the two-dimensional time domain OTFS signal x T ,Right now 6. A high-dimensional index modulation (OTFS) implementation system based on wavelet transform, used to implement a high-dimensional index modulation (OTFS) implementation method based on wavelet transform according to any one of claims 1 to 5, characterized in that: The system includes: a transmitting end and a receiving end; The transmitting end includes: a bit grouper module, an OTFS subframe generator module, an OTFS frame generator module, a discrete wavelet transform module, an inverse discrete wavelet transform module, and a cyclic prefix module; each OTFS subframe generator module includes: an index selector module and a high-dimensional signal mapper module; The receiving end includes: a cyclic prefix removal module, a DWT module, an IDWT module, a minimum mean square error equalizer and maximum likelihood detection module, an OTFS subframe demodulator module, and a bit generator module; each OTFS subframe demodulator includes: an index detector module and a high-dimensional signal demapper module.

7. An electronic device, characterized in that: The electronic device comprises a processor (501), a memory (505), a user interface (503) and a network interface (504), wherein the memory (505) is used to store instructions, the user interface (503) and the network interface (504) are used to communicate with other devices, and the processor (501) is used to execute the instructions stored in the memory (505) so that the electronic device executes the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions, and when the instructions are executed by a computer, the method according to any one of claims 1 to 5 is executed.

Images