Method and system for implementing OTSM based on three-mode index modulation

Abstract

The application belongs to the field of wireless communication, and specifically discloses a kind of OTSM implementation method and system based on three-mode index modulation, the method includes: introducing mode A, mode B and silence mode Z in the time delay-sequence domain of OTSM, three-mode index modulation mapping is completed using mutually non-overlapping constellation diagram, and time delay-sequence domain OTSM signal is constructed;Walsh-Hadamard transform technology is used to modulate time delay-sequence domain OTSM signal, time domain OTSM signal is obtained, after adding cyclic prefix, it is sent into channel for transmission;The cyclic prefix of time domain OTSM signal is removed, after Walsh-Hadamard transform and equalization, log likelihood ratio detection is carried out to each subframe, according to the activation mode of the maximum cumulative log likelihood ratio value, index bit is recovered, according to the activation mode of the decision symbol bit, original information bit stream is reconstructed.The application can effectively improve the spectral efficiency and mode selection flexibility, while reducing the complexity of detector.

Description

Technical Field

[0001] This application belongs to the field of wireless communication, and more specifically, relates to an OTSM implementation method and system based on three-mode indexed modulation. Background Technology

[0002] In traditional Orthogonal Time Sequency Multiplexing (OTSM) systems, information bits are directly mapped onto a two-dimensional signal constellation diagram in the time-delay-sequence domain and modulated using the Walsh-Hadamard Transform (WHT). This system fully leverages the inherent advantage of OTSM in combating time-frequency dual-selective fading in high-speed mobile scenarios, but its spectral efficiency is comparable to that of traditional OFDM, leaving considerable room for improvement.

[0003] To improve the spectral efficiency of OTSM systems, indexed modulation-based OTSM systems (OTSM-IM) transmit additional information bits by activating the index of specific grid cells, effectively improving spectral efficiency without increasing the modulation order. However, existing OTSM-IM systems can only use a single constellation diagram, limiting further improvements in spectral efficiency.

[0004] To address the aforementioned issues, the dual-mode indexed modulation OTSM (OTSM-DM-IM) system employs two disjoint signal constellation diagrams, dividing the active grid cells into two subsets, each mapped using a different constellation diagram. This design eliminates silent grid cells, significantly improving spectral efficiency. However, its dual-mode design only provides two non-zero states, limiting the flexibility of mode selection. To achieve optimal bit error rate performance, the receiver typically requires a maximum likelihood (ML) detector, whose computational complexity increases exponentially with the number of active grid cells and the modulation order, resulting in high system implementation costs and making it difficult to deploy in practical communication equipment.

[0005] Therefore, how to improve the spectral efficiency and mode selection flexibility of OTSM systems while reducing detector complexity is a problem that urgently needs to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this application is to provide an OTSM implementation method and system based on three-mode index modulation, which can improve the spectral efficiency and mode selection flexibility of the OTSM system while reducing detector complexity.

[0007] To achieve the above objectives, in a first aspect, this application provides an OTSM implementation method based on three-mode index modulation, comprising the following steps: S10, Introduce three states—first mode, second mode, and silent mode—into the time delay-sequence domain of OTSM, and use the non-overlapping first constellation diagram and second constellation diagram to complete the three-mode index modulation mapping and construct the time delay-sequence domain OTSM signal; S20, the time-delay-sequence domain OTSM signal is modulated using Walsh-Hadamard transform technology to obtain a time-domain OTSM signal, which is then sent into the channel for transmission after a cyclic prefix is ​​added; S30: After removing the cyclic prefix from the received time-domain OTSM signal, performing Walsh-Hadamard transform and equalization, log-likelihood ratio detection is performed on each subframe: For each grid cell in the subframe, the log-likelihood factor of its belonging to the first mode, the second mode, and the silent mode is calculated. According to the preset legal activation mode lookup table, all possible activation modes are traversed. For each hypothetical activation mode, the log-likelihood factors of all corresponding grid cells are accumulated to obtain the cumulative log-likelihood ratio. The activation mode with the largest cumulative log-likelihood ratio is selected as the decision result to recover the index bits. According to the determined activation mode, the signal of each grid cell is hard-determined. The nearest neighbor point is found in the corresponding first constellation diagram, second constellation diagram, or near the zero point to recover the symbol bits. The index bits and symbol bits recovered from all subframes are merged to reconstruct the original information bit stream.

[0008] As a further preferred embodiment, in step S10, each frame of OTSM signal is transmitted c TM Each information bit is mapped to a [missing information] through three-mode index modulation. M × N A two-dimensional matrix, c TM Bits are divided by the bit blocker module G Groups, each group contains p = c TM / G bits, of which G = M × N / L , M × N This represents the grid size of a time-delay sequence domain OTSM signal. L This represents the number of grid cells in each OTSM signal subframe; the total number of active grid cells in an OTSM signal subframe is... K , K < L ,in K A One grid is assigned to the first mode. K B Each grid is assigned to the second mode, and K = K A + KB Remaining L - K Each grid is in silent mode, transmitting 0 signals.

[0009] As a further preferred embodiment, in any frame of OTSM signal, the... g In each subframe, 1 ≤ g ≤ G , in each subframe p Bits are divided into p 1 bit and p 2 bits, p = p 1+ p 2, of which p 1 is the index bit, used to determine the activation mode. p 2 represents the sign bit; Index bits p 1 is determined by the polynomial coefficients, that is p 1= log2( C ( L , K ) × C ( K , K A )) ,in C (·,·) are the binomial coefficients. · Indicates the plateau function, i.e., floor function; sign bit. p 2 by K A ×log2( N A ) + K B ×log2( N B ) decision, among which N A and N B These are the modulation orders of the first and second constellation diagrams, respectively.

[0010] As a further preferred option, based on the index bits p 1. Determine an activation mode from a preset set of legal activation modes. This mode defines the state of each grid cell within a subframe. Based on the activation mode, map symbol bits to the corresponding grid cells: grid cells in the first mode use the first constellation diagram for symbol mapping, grid cells in the second mode use the second constellation diagram for symbol mapping, and grid cells in the silent mode have a mapping value of 0.

[0011] As a further preferred embodiment, in step S20, the modulation using the Walsh-Hadamard transform technique specifically includes: Construct the normalized Walsh-Hadamard transformation matrix W N ; For the time-delay-sequence domain OTSM signal matrix X DS Perform an inverse Walsh-Hadamard transform on each row to obtain the time-delay-time domain signal matrix X. DT , ; The time-delay-time domain signal matrix X DT Column vectorization yields the time-domain OTSM signal s. T0 , ; P to s through row-column interleaving permutation matrix T0 Perform an interleaving operation to obtain the time-domain OTSM signal s. T Its equivalent matrix form can be expressed as:

[0012] Where x DS For X DS The vector form of I M for M 3D identity matrix This represents the Kronecker product.

[0013] As a further preferred embodiment, in step S30, after removing the cyclic prefix from the received time-domain OTSM signal, the time-domain signal r after removing the cyclic prefix is... T Fold by column M × N The size of the matrix yields the delay-time domain. DT ;right DT Performing an N-point Walsh-Hadamard transform yields the received symbol matrix Y in the time-delay-sequence domain. DS , ; For Y DS Perform minimum mean square error equalization to obtain the equalized signal matrix. DS ;right DS Deinterweave to restore the subframe structure.

[0014] As a further preferred embodiment, in the log-likelihood ratio detection, for the first... g The first subframe i a symbol The log-likelihood factor belonging to the first mode is calculated according to the following formula. :

[0015] The log-likelihood factor belonging to the second mode is calculated using the following formula. :

[0016] Calculate the log-likelihood factor for the silent mode using the following formula. :

[0017] in, and Defined as:

[0018]

[0019] in, For noise variance, for The n A constellation map point, for The m A constellation map point.

[0020] As a further preferred option, for each legitimate activation mode... The first pattern index set defined according to this pattern Second mode index set Silent mode index set The cumulative log-likelihood ratio is calculated using the following formula:

[0021] The activation mode with the largest cumulative log-likelihood ratio is selected as the optimal activation mode, and the index bits are recovered.

[0022] Secondly, this application provides an OTSM implementation system based on tri-mode indexed modulation, for implementing the steps of the method described in any one of the above, including a transmitting end and a receiving end; The transmitting end includes a bit blocker module, an OTSM subframe generator module, an OTSM frame generator module, an inverse Walsh-Hadamard transform module, a vectorization and interleaving module, and a cyclic prefix module; each OTSM subframe generator includes an index selector module, a first constellation map mapper module, and a second constellation map mapper module; The receiver includes a cyclic prefix removal module, a shaping and deinterleaving module, a Walsh-Hadamard transform module, a minimum mean square error equalizer, a three-mode indexed modulation log-likelihood ratio detector module, an OTSM subframe demodulator module, and a bit integrator module; each OTSM subframe demodulator includes an index detector module, a first constellation diagram mapper module, and a second constellation diagram mapper module.

[0023] Thirdly, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method as described in any one of the above.

[0024] The beneficial effects of the technical solution provided in this application are: (1) Higher spectral efficiency and flexibility: By introducing three-mode (A / B / Z) states, more index bits can be transmitted compared to traditional binary (active / silent) index modulation. At the same time, by reasonably selecting two non-overlapping constellation diagrams, the spectral efficiency of the system can be adjusted more flexibly, especially under low-order modulation, the advantages are obvious; (2) Stronger robustness: The tri-mode design combined with the inherent anti-Doppler and anti-multipath capabilities of OTSM enables the system to exhibit better bit error rate performance in high-speed mobile scenarios. (3) Lower peak-to-average power ratio: Due to the presence of the silent mode Z, the signal energy distribution is more uniform. Compared with the fully activated dual-mode system, this application has better PAPR suppression capability, which is beneficial to the linear operation of the power amplifier. (4) Lower detector complexity: The designed tri-mode indexed modulation LLR detector makes decisions by accumulating log-likelihood factors, avoiding the exponential traversal of all possible symbol combinations by the ML detector, thus greatly reducing the detection complexity from exponential to linear, while its performance is close to that of the ML detector, making it very suitable for actual hardware deployment. Attached Figure Description

[0025] Figure 1 This is a flowchart of the method provided in this application; Figure 2 This is a structural diagram of the transmitter end of the three-mode indexed modulation OTSM system provided in this application; Figure 3 This is a structural diagram of the receiver end of the three-mode indexed modulation OTSM system provided in this application; Figure 4 This is a comparison chart of the system bit error rate performance provided in the embodiments of this application; Figure 5 This is a schematic diagram of the electronic device structure provided in this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] It should be understood that, in the description of this application, the terms "first" and "second," etc., are used to distinguish different objects, rather than to describe a specific order of objects.

[0028] To address the issues of insufficient spectral efficiency and limited flexibility of dual-mode indexed modulation in existing OTSM systems, this application provides an OTSM implementation method and system based on tri-mode indexed modulation.

[0029] like Figure 1 As shown, the OTSM implementation method includes the following steps: S1: Introduce three states, Mode A, Mode B and Silent Mode Z, into the time delay-sequence domain of OTSM. Use non-overlapping constellation diagrams to complete the three-mode index modulation mapping and construct the time delay-sequence domain OTSM signal. S2: The Walsh-Hadamard transform (WHT) technique is used to modulate the time-delay-sequence domain OTSM signal to obtain a two-dimensional time-domain OTSM signal. A cyclic prefix is ​​added and the quantized signal is sent to the time-varying multipath channel in a high-speed mobile scenario for transmission. S3: Design a low-complexity LLR detector based on valid activation mode constraints at the receiver. By accumulating the likelihood factors of each grid cell that satisfies the index mode table, select the optimal activation mode and recover the information bits, thereby realizing an OTSM system based on three-mode index modulation.

[0030] Specifically, step S1 may include: Each OTSM signal frame sends c TM Each information bit is mapped to a [missing information] through three-mode index modulation. M × N A two-dimensional matrix, c TM Bits are divided by the bit blocker module G Groups, each group contains p = c TM / G bits, of which G = M × N / L , M × N This represents the grid size of a time-delay sequence domain OTSM signal. L This indicates the number of grid cells in each OTSM signal subframe; In an OTSM signal subframe, the total number of active grids is K ( K < L ),in K A One grid is assigned to pattern A. K B A grid is assigned to pattern B, and satisfies K = K A + K B Remaining L - K Each grid is in silent mode Z, transmitting a 0 signal.

[0031] Step S1 may also include: The steps to complete the three-mode index modulation mapping using non-overlapping first and second constellation diagrams are as follows: In any frame of OTSM signal g In each subframe, 1 ≤ g ≤ G , in each subframe p Bits are divided into p 1 bit and p 2 bits, that is p = p 1+ p 2, p 1 is the index bit, used to determine the activation mode. p 2 represents the sign bit; Index bits p 1 is determined by the polynomial coefficients, that is p 1= log2( C ( L , K ) × C ( K , K A )) ,in C (·,·) are the binomial coefficients; Symbol bits p 2 by K A ×log2( N A ) + K B ×log2( N B ) decided, among which, Representing constellations The magnitude of the modulation order.

[0032] Based on index bits p 1. Determine an activation mode from the preset set of legal activation modes (A / B / Z), which defines the state of each grid cell within the subframe.

[0033] For the Subframe The reference set of pattern A can be represented as Mapping symbol vector ,in .

[0034] The index set of pattern B is Mapping symbol vector ,in Remaining index set of pattern Z Mapping symbol vector , where all symbols are 0.

[0035] According to the activation mode, symbol bits are mapped to the corresponding grid cells: grid cells in mode A use the first constellation diagram for symbol mapping; grid cells in mode B use the second constellation diagram for symbol mapping; and grid cells in silent mode Z have a mapping value of 0. This application provides an embodiment as follows, when L = 4, K = 2, K A = K B When = 1, an OTSM subframe U based on tri-mode indexed modulation g The implementation is shown in Table 1: Table 1

[0036] Cascade all G Each subframe is interleaved to construct a M × N A two-dimensional matrix, i.e., an OTSM signal X in the time-delay-sequence domain. DS .

[0037] Step S2 may specifically include: S21: Construct the normalized Walsh-Hadamard transformation matrix W N ; S22: For the time-delay-sequence domain OTSM signal matrix X DS Perform an inverse Walsh-Hadamard transform on each row to obtain the time-delay-time domain signal matrix X. DT ,Right now: (1) S23: X DTColumn vectorization yields the time-domain OTSM signal s. T0 ,Right now: (2) Based on the transformation and vectorization operations described in S21 to S23, s is further processed by the row-column interleaving permutation matrix P. T0 Perform an interleaving operation to obtain the time-domain OTSM signal s. T Its equivalent matrix form can be expressed as: (3) Where x DS For X DS The vector form of I M for M 3D identity matrix This represents the Kronecker product.

[0038] Optionally, step S3 includes: S31: The receiver receives the signal, removes the cyclic prefix, and converts the received time-domain signal r... T Fold by column M × N The size of the matrix yields the delay-time domain. DT Then proceed N By using WHT, the received symbol matrix Y in the time-delay-sequence domain is obtained. DS ; S32: For Y DS Minimum mean square error (MMSE) equalization is performed to suppress channel interference and obtain the equalized signal. DS ; S33: Yes DS Perform deinterleaving to restore the subframe structure; S34: Perform three-mode indexed modulation LLR detection for each subframe: S341: For each grid cell in the subframe, calculate its log-likelihood factor for belonging to mode A, mode B, and silent mode Z, respectively. ; For the g The first subframe i a symbol The log-likelihood factor belonging to pattern A, B, or Z They are represented as follows: (4) (5) (6) In equations (4) and (5), and Defined as: (7) (8) In equations (7) and (8), For noise variance, for The n A constellation map point, for The m A constellation map point.

[0039] To recover the index bits The optimal activation mode needs to be selected based on a predefined lookup. Define the index bits. The corresponding lookup table contains A legitimate activation mode, for the first A pattern is defined by three disjoint sets of indices. Let these represent the sets of grid indices in patterns A, B, and Z, respectively, satisfying... To determine the optimal active index, the cumulative LLR factor value of all possible index patterns is calculated, and the pattern corresponding to the maximum value is selected, i.e.: (9) The optimal indexing mode has been determined. Then, the index bits can be recovered. Then, using the mapping method corresponding to this index pattern, symbol demapping is performed to recover the symbol bits. .

[0040] S342: Based on the preset legal activation mode lookup table, traverse all possible activation modes; S343: Activation mode for each hypothesis ξ The cumulative LLR value of the model is obtained by summing the log-likelihood factors of all its corresponding grid cells. S344: Select the activation mode with the largest cumulative LLR value as the decision result, thereby recovering the index bits; S345: Based on the determined activation mode, perform hard decision on the signal of each grid cell, and find the nearest neighbor in the corresponding constellation diagram (A or B) or near the zero point to recover the symbol bit; S35: Merge the index bits and symbol bits recovered from all subframes to reconstruct the original information bit stream.

[0041] See Figure 2The three-mode indexed modulation OTSM system transmitter provided in this application includes: a bit blocker module, an OTSM subframe generator module, an OTSM frame generator module, an inverse Walsh-Hadamard transform (IWHT) module, a vectorization and interleaving module, and a cyclic prefix module; each OTSM subframe generator includes: an index selector module, a first constellation map mapper module, and a second constellation map mapper module.

[0042] Reference Figure 3 The receiver of a tri-mode indexed modulation (OTSM) system includes: a cyclic prefix removal module, a shaping and deinterleaving module, a Walsh-Hadamard transform (WHT) module, a minimum mean square error (MMSE) equalizer and a tri-mode indexed modulation LLR detector module, an OTSM subframe demodulator module, and a bit integrator module. Each OTSM subframe demodulator includes: an index detector module, a first constellation diagram mapper module, and a second constellation diagram mapper module.

[0043] This application provides an example, as follows: In an OTSM system based on tri-mode indexed modulation in this application, BPSK is used as the first constellation diagram (A) and BPSK as the second constellation diagram (B). Other parameters are as follows. M = N = 16, L = 4, K = 2, K A = K B = 1. The mapping relationship is shown in Table 1. 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 The frame OTSM signal is used for bit error rate statistics at the receiver.

[0044] Ignoring the effect of the cyclic prefix, the spectral efficiency of this application can be calculated as follows:

[0045] Figure 4 A comparison chart of the system bit error rate (BER) performance of this application with conventional techniques 1 (using a BPSK constellation diagram), 2 (using a QPSK constellation diagram), and 3 (using BPSK as constellation diagram A and BPSK as constellation diagram B) is provided. Simulation results show that the OTSM-TM-IM system proposed in this application outperforms the reference systems at the same or similar spectral efficiency. For conventional technique 1, it has higher spectral efficiency and BER performance; for conventional techniques 2 and 3, it has better BER performance.

[0046] For each subframe, the computational complexity of the LLR detector based on tri-mode indexed modulation mainly consists of two parts: index detection and data symbol detection, with a complexity of O(n). The complexity of using an ML detector is O(n). ,when N A = 4, N B = 8, and the specific complexity comparison is shown in Table 2. It can be seen that the LLR detector set based on three-mode index modulation designed in this application greatly reduces the computational complexity.

[0047] Table 2

[0048] The key technical point of this application is: (1) This application is the first to apply three-mode index modulation technology to the OTSM system. Through the design of three states (A / B / Z), the system robustness is enhanced while improving the spectrum efficiency. (2) This application designs a low-complexity LLR detector based on legal activation mode constraints to address the characteristics of three-mode index modulation. This effectively solves the problem of high complexity and difficulty in implementation of traditional ML detectors, and achieves a balance between reliability, effectiveness and low complexity.

[0049] This application also discloses an electronic device. (See reference...) Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device disclosed in an embodiment of this 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.

[0050] The communication bus 502 is used to enable communication between these components.

[0051] The user interface 503 may include a display screen, and optionally, the user interface 503 may also include a standard wired interface or a wireless interface.

[0052] The network interface 504 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0053] This application also discloses a computer-readable storage medium storing multiple instructions adapted for loading by a processor to execute the above-described high-dimensional indexed modulation OTFS implementation method based on wavelet transform.

[0054] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for implementing OTSM based on three-mode indexed modulation, characterized in that, Includes the following steps: S10, Introduce three states—first mode, second mode, and silent mode—into the time delay-sequence domain of OTSM, and use the non-overlapping first constellation diagram and second constellation diagram to complete the three-mode index modulation mapping and construct the time delay-sequence domain OTSM signal; S20, the time-delay-sequence domain OTSM signal is modulated using Walsh-Hadamard transform technology to obtain a time-domain OTSM signal, which is then sent into the channel for transmission after a cyclic prefix is ​​added; S30: After removing the cyclic prefix from the received time-domain OTSM signal, performing Walsh-Hadamard transform and equalization, log-likelihood ratio detection is performed on each subframe: For each grid cell in the subframe, the log-likelihood factor of its belonging to the first mode, the second mode, and the silent mode is calculated. According to the preset legal activation mode lookup table, all possible activation modes are traversed. For each hypothetical activation mode, the log-likelihood factors of all corresponding grid cells are accumulated to obtain the cumulative log-likelihood ratio. The activation mode with the largest cumulative log-likelihood ratio is selected as the decision result to recover the index bits. According to the determined activation mode, the signal of each grid cell is hard-determined. The nearest neighbor point is found in the corresponding first constellation diagram, second constellation diagram, or near the zero point to recover the symbol bits. The index bits and symbol bits recovered from all subframes are merged to reconstruct the original information bit stream.

2. The OTSM implementation method based on three-mode index modulation as described in claim 1, characterized in that, In step S10, each frame of OTSM signal is transmitted c TM Each information bit is mapped to a [missing information] through three-mode index modulation. M × N A two-dimensional matrix, c TM Bits are divided by the bit blocker module G Groups, each group contains p = c TM / G bits, of which G = M × N / L , M × N This represents the grid size of a time-delay sequence domain OTSM signal. L This indicates the number of grid cells in each OTSM signal subframe; In an OTSM signal subframe, the total number of active grids is K , K < L ,in K A One grid is assigned to the first mode. K B Each grid is assigned to the second mode, and K = K A + K B Remaining L - K Each grid is in silent mode, transmitting 0 signals.

3. The OTSM implementation method based on three-mode index modulation as described in claim 2, characterized in that, In any frame of OTSM signal g In each subframe, 1 ≤ g ≤ G , in each subframe p Bits are divided into p 1 bit and p 2 bits, p = p 1+ p 2, of which p 1 is the index bit, used to determine the activation mode. p 2 represents the sign bit; Index bits p 1 is determined by the polynomial coefficients, that is p 1 = log2( C ( L , K ) × C ( K , K A )) ,in C (·,·) are the binomial coefficients. · Indicates the plateau function, i.e., floor function; sign bit. p 2 by K A ×log2( N A ) + K B ×log2( N B ) decision, among which N A and N B These are the modulation orders of the first and second constellation diagrams, respectively.

4. The OTSM implementation method based on three-mode index modulation as described in claim 3, characterized in that, Based on index bits p 1. Determine an activation mode from a preset set of legal activation modes, which defines the state of each grid cell within the subframe; According to the activation mode, symbol bits are mapped to the corresponding grid cells: grid cells in the first mode use the first constellation diagram for symbol mapping, grid cells in the second mode use the second constellation diagram for symbol mapping, and grid cells in the silent mode have a mapping value of 0.

5. The OTSM implementation method based on three-mode index modulation as described in claim 1, characterized in that, In step S20, the modulation using the Walsh-Hadamard transform technique specifically includes: Construct the normalized Walsh-Hadamard transformation matrix W N ; For the time-delay-sequence domain OTSM signal matrix X DS Perform an inverse Walsh-Hadamard transform on each row to obtain the time-delay-time domain signal matrix X. DT , ; The time-delay-time domain signal matrix X DT Column vectorization yields the time-domain OTSM signal s. T0 , ; P to s through row-column interleaving permutation matrix T0 Perform an interleaving operation to obtain the time-domain OTSM signal s. T Its equivalent matrix form can be expressed as: Where x DS For X DS The vector form of I M for M 3D identity matrix This represents the Kronecker product.

6. The OTSM implementation method based on three-mode index modulation as described in claim 5, characterized in that, In step S30, after removing the cyclic prefix from the received time-domain OTSM signal, the time-domain signal r after removing the cyclic prefix is... T Fold by column M × N The size of the matrix yields the delay-time domain. DT ;right DT Performing an N-point Walsh-Hadamard transform yields the received symbol matrix Y in the time-delay-sequence domain. DS , ; For Y DS Perform minimum mean square error equalization to obtain the equalized signal matrix. DS ;right DS Deinterweave and restore the subframe structure.

7. The OTSM implementation method based on three-mode index modulation as described in claim 6, characterized in that, In the aforementioned log-likelihood ratio detection, for the first... g The first subframe i a symbol The log-likelihood factor belonging to the first mode is calculated according to the following formula. : The log-likelihood factor belonging to the second mode is calculated using the following formula. : Calculate the log-likelihood factor for the silent mode using the following formula. : in, and Defined as: in, For noise variance, for The n A constellation map point, for The m A constellation map point.

8. The OTSM implementation method based on three-mode index modulation as described in claim 7, characterized in that, For each valid activation mode The first pattern index set defined according to this pattern Second mode index set Silent mode index set The cumulative log-likelihood ratio is calculated using the following formula: The activation mode with the largest cumulative log-likelihood ratio is selected as the optimal activation mode, and the index bits are recovered.

9. An OTSM implementation system based on three-mode indexed modulation, characterized in that, The steps for implementing the method of any one of claims 1 to 8 include a transmitting end and a receiving end; The transmitting end includes a bit blocker module, an OTSM subframe generator module, an OTSM frame generator module, an inverse Walsh-Hadamard transform module, a vectorization and interleaving module, and a cyclic prefix module; each OTSM subframe generator includes an index selector module, a first constellation map mapper module, and a second constellation map mapper module; The receiver includes a cyclic prefix removal module, a shaping and deinterleaving module, a Walsh-Hadamard transform module, a minimum mean square error equalizer, a three-mode indexed modulation log-likelihood ratio detector module, an OTSM subframe demodulator module, and a bit integrator module; each OTSM subframe demodulator includes an index detector module, a first constellation diagram mapper module, and a second constellation diagram mapper module.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method as described in any one of claims 1 to 8.

Images