A physical layer security transmission method based on concatenated serial number modulation

Abstract

The application discloses a kind of physical layer security transmission methods based on cascade serial number modulation, the transmission method is that multiple different function serial number modulation is combined by cascade mode, realizes physical layer security transmission under the condition of not affecting the spectral efficiency of original carrier serial number modulation.The application utilizes the effect that serial number modulation can break original sequence, by corresponding scrambling order serial number modulation to modulation symbol bit and the sending symbol vector after completing carrier serial number modulation respectively, effectively break the order of original bit sequence and sending symbol vector, realize the security transmission of information.Only legal user uses the consensus information of transceiver end to do descrambling order serial number modulation processing after receiving end, can correctly demodulate the sending information, and illegal user cannot correctly demodulate the sending information when lacking consensus information, improve the information transmission security between legal user.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically to a physical layer secure transmission method based on concatenated sequence number modulation. Background Technology

[0002] Secure information transmission is one of the most critical issues facing 5G and next-generation mobile and short-range wireless communications. Due to the openness of wireless channels, information sent between legitimate users can be received by eavesdroppers, leading to information leaks. Currently, the main method of information security protection is cryptographic encryption, which uses keys to encrypt information and achieves secure transmission at the network layer and higher. This implementation requires devices with sufficient computing power. Physical layer security technology is an effective supplementary solution to traditional encryption methods. It protects information transmission between legitimate users through physical layer modulation techniques, channel information between legitimate users, and the addition of artificial noise to assist transmission, effectively reducing the ability of eavesdropping devices to correctly demodulate signals.

[0003] Existing technologies include physical layer secure transmission methods based on spatial modulation. These methods redefine antenna numbers used for mapping spatial bit information by sorting the column vector of legitimate channel state information in ascending order of its 2-norm. When an eavesdropping user is unaware of the channel state information between the transmitter and the legitimate user, even if the eavesdropping user correctly detects the modulation information and active antenna number at the transmitter, they cannot determine the antenna number used to map the spatial bit information, and therefore cannot correctly recover the spatial bit information. However, this method suffers from limited transmission methods and low security. Summary of the Invention

[0004] The main objective of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a physical layer secure transmission method based on cascaded sequence modulation. This method effectively combines multiple sequence modulations and increases the physical layer secure transmission capability by cascading sequence modulations with other functions while retaining the ability to transmit sequence modulation information. This achieves physical layer secure information transmission based on the cascaded combination of multiple sequence modulations.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a physical layer secure transmission method based on concatenated sequence number modulation, which achieves physical layer secure transmission through multiple concatenated sequence number modulation modes, including the following steps:

[0007] S1. At the transmitting end, N of each OFDM symbol A The subcarriers are divided into G sub-blocks, each sub-block containing N s =N A / G subcarriers, each sub-block is independently cascaded sequence number modulation to achieve secure physical layer transmission;

[0008] S2. According to the subcarrier segmentation method, the m information bits of each OFDM symbol input are divided into G corresponding groups. The information bits corresponding to each sub-block are p = m / G, where the p information bits are further divided into two groups. The p1 sequence number modulation bits of the first group are used for sub-block sequence number modulation from N. s K subcarriers are selected from the first subcarriers to transmit modulation symbols, and the p2 modulation symbol bits of the second group are used for modulation symbol mapping to generate K modulation symbols;

[0009] S3. Based on the number of modulation symbol bits, perform sequence modulation on the information bits using scrambling sequence number modulation with a dimension of p2, and then apply the scrambling sequence number pattern... The obtained modulation symbol bits after sequence number modulation processing are in Bit scrambling sequence number pattern The corresponding matrix, p2, is the information bit vector before bit scrambling sequence number modulation. This is the information bit vector after bit scrambling sequence number modulation;

[0010] S4. Based on the p1 sequence modulation bits of the first group of each sub-block, the active subcarrier sequence pattern of the g-th (1≤g≤G) sub-block is obtained as follows: in ij≠i k When j≠k, and The elements in the array are arranged in ascending order;

[0011] The information bit vector modulated according to the scrambling sequence number of the p2 modulation symbol bits in the second group of each sub-block The modulation symbol vector of the i-th sub-block is s g = [s1, s2, ..., s K ] T ;

[0012] Based on the obtained active subcarrier sequence pattern and modulation symbol vector s g The symbol vector of the g-th sub-block is obtained as follows: Where the modulation symbol vector s g Mapping to the active subcarrier sequence pattern The corresponding subcarrier, i.e.

[0013] S5. Based on the symbol vector dimension, use a dimension of size N. s Symbol vector perturbation sequence number pattern pair x gPerform scrambling sequence modulation, and scramble the sequence pattern according to the symbol vector. The symbol vector after scrambling sequence modulation can be obtained. for in Disruption of the symbol vector sequence pattern The corresponding N s ×N s Matrix;

[0014] S6. After obtaining the symbol vectors of all G sub-blocks, the G sub-blocks are connected in order of their sub-block numbers to obtain the complete concatenated sequence number modulation transmission symbol vector. After frequency domain block interleaving, the final frequency domain transmission symbol vector is obtained.

[0015] S7, After transmitting the symbol vector x in the frequency domain F The inverse Fourier transform yields the time-domain transmitted signal vector. Add a length of N to the front end of the transmitted symbol vector. CP After the cyclic prefix CP is applied, the final time-domain transmitted symbol vector is obtained. After processing such as parallel-to-serial conversion and digital-to-analog conversion, it is transmitted to the receiver via the antenna.

[0016] S8. The time-domain received signal vector received at the receiving end after transmission through the wireless channel is: After removing the cyclic prefix (CP), a Fourier transform is performed to obtain the frequency domain received signal vector. Then, a reverse block deinterleaving operation is performed to restore the original frequency domain received signal vector.

[0017] Based on the sub-block grouping method of the transmitter sequence modulation, the frequency domain received signal vector is divided into corresponding G sub-blocks. Then, the frequency domain received signal vector of the g-th (1≤g≤G) sub-block is:

[0018]

[0019] in The power adjustment factor at the transmitting end. and The frequency domain received signal vector before descrambling sequence number modulation processing, frequency domain channel state information, frequency domain transmitted symbol vector, and frequency domain Gaussian white noise vector with mean 0 and variance N0 are included.

[0020] S9. Perform descrambling sequence number modulation processing on the received signal vector of the g-th sub-block to restore the original order of the frequency domain received signal vector of the g-th sub-block. The corresponding channel state information vector at this time is The transmitted symbol vector is The frequency domain Gaussian white noise vector is

[0021] After descrambling sequence number modulation processing, the received signal vector y of the g-th sub-block g =γdiag(h g )x g +w g ;

[0022] S10. Based on the received signal vector model of the g-th sub-block, calculate the most likely transmitted modulation symbol and corresponding metric value for each subcarrier under a given active and inactive state. The most likely transmitted symbol vector under a given active state is:

[0023]

[0024] The corresponding metric value is:

[0025]

[0026] When a symbol of 0 is sent during inactivity, the metric value is:

[0027]

[0028] Where n = 1, 2, ..., N s , Represents an M-order constellation diagram;

[0029] S11, the estimated transmitted symbol vector of the g-th sub-block is:

[0030]

[0031] Based on the obtained transmitted symbol vector estimate Demodulation yields the transmitted p1 sequence modulation bits and p2 modulation symbol bits. in After bit descrambling and sequence number modulation, the original bit order of the information is restored.

[0032] As a preferred technical solution, in step S2, based on the sequence number modulation method, the first group is... N numbered modulation bits, where C(N) s Calculation of K) combinations The calculation is performed by rounding down; the second group consists of p2 = Klog2M modulation symbol bits, where M is the order of the modulation constellation diagram.

[0033] As a preferred technical solution, in step S3, the modulation symbol bits are processed by sequence modulation with bit scrambling order to scramble the original order of the modulation symbol bits and obtain a new bit sequence. This prevents illegal receiving nodes from obtaining the adjustment symbol bit p2 of each sub-block through demodulation of the received modulation symbols;

[0034] For the bit scrambling sequence number pattern of the g-th sub-block Where r is true when j≠k j ≠r k Its corresponding p2×p2 matrix Each row contains only one non-zero element, 1, and its position index is determined by... The corresponding element in the array, i.e., the position index of element 1 in the k-th row, is r. k The remaining elements are 0.

[0035] As a preferred technical solution, the bit scrambling sequence number modulation pattern There are a total of KM! available patterns, and N can be selected. B A pattern is used for bit scrambling sequence number modulation, where the sequence number is i∈{1,2,...,N}. B};

[0036] During information transmission, legitimate users can obtain a set of pseudo-random sequences i that are agreed upon by both the sender and receiver through methods such as a codebook, channel state information based on legitimate users, or key information transmission assisted by artificial noise. B = {i1, i2, i3, ...}, where i1, i2, i3, ... ∈ {1, 2, ..., N} B}

[0037] As a preferred technical solution, in step S4, the number of available active subcarrier sequence number patterns is C(N). s , K), and the number of active subcarrier sequence number patterns used in sequence modulation is a power of 2, therefore we have An unused, illegally activated subcarrier sequence number pattern.

[0038] As a preferred technical solution, in step S5, the dimension N is used. s The symbol vector scrambling sequence number modulation scrambles the order of all modulation symbols in the transmitted symbol vector of the sub-block, and each sub-block performs independent symbol vector scrambling sequence number modulation.

[0039] The symbol vector perturbation sequence number pattern of the g-th sub-block is as follows: Its corresponding N s ×N s matrix Each row contains only one non-zero element, 1, whose position index is determined by... The corresponding element in the array is determined, that is, the position index of element 1 in the k-th row is r. k All other elements are 0;

[0040] Using matrices Left-multiply the sent symbol vector x g The transmitted symbol vector after scrambling order is obtained. By effectively altering the active subcarrier sequence number pattern and the modulation symbol order in the transmitted symbol vector, the active subcarrier sequence number pattern of some transmitted symbol vectors will be mapped to the illegal active subcarrier sequence number pattern after the sequence number modulation is disrupted.

[0041] As a preferred technical solution, the dimension is N. s Symbol vector disturbance sequence number pattern From N s ! Select N from the available patterns X One is used for symbol vector scrambling sequence number modulation, where

[0042] Legitimate users can obtain consensus information through methods such as codebooks, channel state information based on legitimate users, and artificial noise-assisted transmission of key information, using a set of consensus pseudo-random sequences. Implement scrambled sequence number modulation and descrambled sequence number modulation among legitimate users, where i1, i2, i3, ... ∈ {1, 2, ..., N}. X}

[0043] As a preferred technical solution, in step S9, the received signal vector and channel estimation vector of each sub-block are multiplied by the inverse matrix of the corresponding symbol vector scrambling sequence number modulation matrix. The original sequence is restored, and after descrambling sequence number modulation processing, the received signal vector model with the original sequence restored is obtained.

[0044] As a preferred technical solution, in step S10, the orthogonality of subcarriers in OFDM is utilized to calculate the most likely symbol to be transmitted and the corresponding metric value of each subcarrier under a given activation and deactivation condition, which is used to make a decision on the transmitted symbol vector based on the entire sub-block.

[0045] As a preferred technical solution, in step S11, a traversal search is performed based on the active subcarrier sequence number pattern of the sub-block and the most likely transmitted symbol obtained by each subcarrier under active and inactive conditions.

[0046] The demodulation yields the modulation symbol bit sequence. Then, in the bit descrambling sequence modulation, the inverse matrix of the bit scrambling sequence modulation matrix is ​​multiplied by the left. Restore the original order of the sequence number modulation bit sequence.

[0047] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0048] (1) The present invention utilizes a cascaded sequence modulation method to sequentially combine multiple sequence modulations with different functions and roles through cascaded combination. This method combines sequence modulation that realizes bit sequence order disturbance, sequence modulation that selects and activates subcarrier mode pattern of traditional transmitted information bits, and sequence modulation that disrupts the order of transmitted symbol vectors into a sequence modulation combination with information security transmission capability, effectively improving the information security transmission capability between legitimate users.

[0049] (2) In the cascaded sequence number modulation method of the present invention, bit scrambling sequence number modulation and symbol vector scrambling sequence number modulation can be independently combined with traditional carrier sequence number modulation to form cascaded sequence number modulation methods with different information security transmission requirements. Moreover, bit scrambling sequence number modulation and symbol vector scrambling sequence number modulation can also be independently combined with traditional OFDM to realize physical layer information security transmission of traditional OFDM. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a flowchart of the physical layer secure transmission method based on concatenated sequence number modulation according to the present invention, wherein... and These represent the modulation symbol bits after the scrambling sequence number processing and the transmitted symbol vector of the g-th sub-block, respectively;

[0052] Figure 2 This is a comparison of the bit error rate performance of legitimate users and illegitimate eavesdropping users when the modulation symbols of the concatenated sequence number modulation based on OFDM-IM subblock parameters N=4, K=2 and the 4QAM constellation diagram are used. Both legitimate and illegitimate users use maximum likelihood receivers calculated based on a single subcarrier. Detailed Implementation

[0053] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0054] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0055] Carrier Sequence Number Modulation (OFDM-IM) is an improvement on traditional OFDM. By grouping and modulating subcarriers, and transmitting information bits through active subcarrier sequence number patterns and sending these active subcarriers to modulation symbols, it achieves better system bit error rate (BER), spectral efficiency, and energy efficiency. With sequence number modulation, subcarriers are selected from K subcarriers in each subblock as active subcarriers to transmit modulation symbols. The sequence number pattern of these K active subcarriers serves as a modulation resource to carry information bits. Multimode Symbol Sequence Number Modulation (MSM) divides the standard constellation diagram into multiple non-overlapping symbol patterns. Information bits are transmitted through these multimode symbol pattern patterns by mapping the symbol pattern patterns to the modulation symbols transmitted by each subcarrier in the subblock. The sequence number pattern pattern changes the traditional sequential vector pattern, allowing the order to be shuffled and recombine into a new vector, which can be used to achieve physical layer secure transmission.

[0056] Cascaded sequence modulation (CMM) effectively combines the effects of multiple sequence modulations by cascading them or combining them into a single joint modulation scheme. This results in more functionality and superior system performance. CMM can effectively combine multiple sequence modulations, and through appropriate signal processing, each sequence modulation can achieve different functions. This adds physical layer security transmission capabilities without affecting traditional information transmission, effectively enhancing information security transmission capabilities in next-generation mobile and wireless communications.

[0057] This invention addresses the need for secure wireless transmission of information between legitimate users and devices in next-generation mobile and wireless communications networks. By combining a concatenated sequence number modulation method, it designs a method for secure information physical layer transmission on a per-sub-block basis, effectively improving the security of information transmission.

[0058] like Figure 1 As shown in this embodiment, a physical layer secure transmission method based on concatenated sequence number modulation uses N in one OFDM symbol period. A A modulation and demodulation method for physical layer secure transmission based on concatenated sequence number modulation is designed based on individual subcarriers, specifically including the following steps:

[0059] S1, at the transmitting end, send the N of an OFDM block A The subcarriers are divided into G independent sub-blocks, each of which performs independent but identical concatenated number modulation and demodulation methods. Each sub-block includes N subcarriers. s =N A / G subcarriers.

[0060] Furthermore, in carrier sequence number modulation, from the N of the sub-block s K subcarriers are selected as active subcarriers from N subcarriers to transmit modulation symbols. At this point, a total of C(N) subcarriers are used. s K) available sequence pattern patterns, where C(·) represents the combinatorial function.

[0061] S2. Divide the m input information bits of each OFDM block into G corresponding groups, where each group contains p = m / G information bits. The p information bits of each sub-block are further divided into two groups, where the first group is... The sequence number modulation bits are used for sub-block sequence number modulation from N s K subcarriers are selected from the first subcarriers for transmitting modulation symbols. The second group consists of p2 = Klog2M modulation symbol bits used for modulation symbol mapping to generate K modulation symbols, where C(N) s Calculation of K) combinations To round down, M is the order of the modulation symbol constellation diagram.

[0062] It is understandable that in cascaded number modulation for physical layer security, each sub-block performs independent and identical cascaded number modulation. This embodiment uses the modulation and demodulation process of the g-th (1≤g≤G) sub-block to illustrate the modulation and demodulation method of cascaded number modulation.

[0063] S3. The original bit vector of the p2 modulation symbol bits in the second group is p2. After modulation by bit scrambling sequence number, a new bit sequence is obtained. Multiply by the bit scrambling sequence number modulation matrix on the left. The original bit vector p2 is used to obtain a new bit sequence with a changed order. The calculation formula is as follows:

[0064]

[0065] in, The bit scrambling sequence number pattern for the g-th sub-block The corresponding p2×p2 matrix has a row containing only one non-zero element 1, and the position of the element 1 in the nth row is determined by... The nth element is given.

[0066] Furthermore, bit scrambling sequence number modulation establishes consensus information among legitimate users. This is achieved through methods such as a codebook, combined with other physical layer security methods, cryptography, and their combinations, to establish a set of pseudo-random sequences i that are agreed upon by both the sender and receiver. B = {i1, i2, i3, ...}, enabling both transmitting and receiving ends to perform sequence number modulation and demodulation based on the same bit scrambling sequence number pattern, where i1, i2, i3, ... ∈ {1, 2, ..., N}. B}, N B This refers to the number of bit scrambling sequence number patterns used. In one embodiment, as shown in Table 1, a scrambling sequence number pattern with a dimension of 4 is given.

[0067] Table 1

[0068]

[0069] Furthermore, the pseudo-random sequence i established by legitimate users for consensus between the sender and receiver is... B = {i1, i2, i3, ...}, where i1, i2, i3, ... ∈ {1, 2, ..., 12}.

[0070] S4. Based on the p1 sequence modulation bits of the g-th sub-block, the active subcarrier sequence number pattern of the g-th sub-block can be obtained as follows: Based on p2 bit vectors modulated by bit scrambling sequence numbers The resulting K modulation symbol vectors are s g = [s1, s2, ..., s K ] T .

[0071] Furthermore, based on the activation subcarrier sequence number pattern of the g-th sub-block and modulation symbol vector s g The transmission vector of the g-th sub-block is The modulation symbol vector is mapped sequentially to the transmitted symbol vector according to the active subcarrier sequence pattern, where:

[0072]

[0073] S5, Use a dimension size of N s Symbol vector perturbation sequence number pattern pair x g Perform scrambling sequence modulation, and scramble the sequence pattern according to the symbol vector. The corresponding N s ×N s matrix Left-multiply the sent symbol vector x g The transmitted symbol vector after scrambling sequence number modulation can be obtained. The calculation formula is as follows:

[0074]

[0075] in, Each row contains only one non-zero element, 1, and its position index is determined by... The corresponding element in the array, i.e., the position index of element 1 in the k-th row, is r. k The remaining elements are 0.

[0076] S6. After obtaining the symbol vectors of all G sub-blocks, the G sub-blocks are concatenated in order of their sub-block numbers to obtain the complete transmit symbol vector. After frequency domain block interleaving, the final concatenated sequence number modulated frequency domain transmit symbol vector is obtained.

[0077] S7. After inverse Fourier transform, the frequency domain symbol vector is... Transformation yields the time-domain signal vector Adding the cyclic prefix CP yields the final transmitted signal vector.

[0078] S8. The time-domain received signal vector after passing through the frequency-selective fading channel is received at the receiving end. After removing the cyclic prefix (CP), the frequency domain received signal vector is obtained through Fourier transform. After deblocking and interleaving, the original order is restored. The frequency domain received signal vector with the restored original order is... Then the frequency domain received signal It can be represented as:

[0079]

[0080] in The power factor at the transmitting end. It is the frequency domain channel response vector. It is a Gaussian white noise vector with a mean of 0 and a variance of N0.

[0081] Furthermore, according to N in each OFDM transmission symbol generated at the transmitting end... A Given the grouping of subcarriers, the received frequency domain signal vector is divided into G corresponding sub-blocks. The frequency domain received signal vector of the g-th sub-block is then:

[0082]

[0083] S9. Perform descrambling sequence number modulation processing on the received signal vector of the g-th sub-block by left multiplying it by the inverse matrix of the transmitting end symbol vector scrambling order matrix. If the received vectors of a sub-block are restored to their original order as transmitted vectors, then the frequency domain received signal vector of the g-th sub-block, after restoring the original order, is:

[0084] y g =γdiag(h g )x g +w g

[0085] in The corresponding channel state information vector at this time is The transmitted symbol vector is The frequency domain Gaussian white noise vector is

[0086] S10. Based on the received signal vector model of the g-th sub-block, the orthogonality between subcarriers is used to calculate the most likely transmission symbol and corresponding metric value of each subcarrier for a given active and inactive state, based on the maximum likelihood criterion. Then, a global decision is made on a sub-block basis. Therefore, the n-th (1≤n≤N) sub-block... s The received signal model for 1 subcarrier is as follows:

[0087] y n =γh n x n +w n

[0088] The most likely transmitted symbol vector for the nth subcarrier when given activation is:

[0089]

[0090] in For an M-order constellation diagram, then The corresponding metric value is:

[0091]

[0092] The nth subcarrier transmits 0 symbols when it is inactive, and the metric value at this time is:

[0093] p n，0 =||y n || 2 .

[0094] S11. Based on the most likely transmitted symbols and corresponding metric values ​​of each subcarrier in the g-th sub-block under active and inactive conditions, the estimated transmitted symbol vector of the g-th sub-block is:

[0095]

[0096] Furthermore, based on the obtained transmitted symbol vector estimate Demodulation yields the transmitted p1 sequence modulation bits and p2 modulation symbol bits. in After bit descrambling and sequence number modulation processing, the original bit order of the information is restored. In the bit descrambling and sequence number modulation process, the original bit order is restored by left multiplying the bit descrambling and sequence number modulation matrix by the inverse matrix. Restore the original bit order

[0097] This invention utilizes a concatenated sequence numbering method to combine sequence number modulations of different functions, thereby enhancing physical layer security transmission capabilities without affecting information transmission and achieving secure information transmission. In the concatenated sequence number modulation, bit scrambling sequence number modulation and symbol vector scrambling sequence number modulation can be combined individually with carrier sequence number modulation to achieve physical layer security transmissions of different security levels.

[0098] This invention can be further illustrated through case simulation:

[0099] This invention obtains simulation results data and simulation graphs through simulation on the MATLAB platform.

[0100] In the simulation, the number of OFDM subcarriers is set to N. B =128 subcarriers, each OFDM-IM subblock has N=4 subcarriers, of which K=2 are active subcarriers used to transmit 4QAM constellation diagram modulation symbols. The wireless channel is a frequency-selective Rayleigh fading channel, the maximum channel delay is 10 sampling slots, the length of the cyclic prefix CP is 16 oversampling periods, and the receiver algorithm uses a single subcarrier maximum likelihood receiver.

[0101] The simulation content compares the bit error rate performance of legitimate users and illegitimate users in the physical layer secure transmission method based on concatenated sequence number modulation of this invention, as well as the comparison between legitimate users using traditional carrier sequence number modulation and the physical layer secure transmission method based on concatenated sequence number modulation.

[0102] Figure 2 The horizontal axis represents the signal-to-noise ratio (SNR) in dB, and the vertical axis represents the system's BER performance. Figure 2 As can be seen, legitimate users achieved the same bit error rate performance as traditional carrier sequence number modulation using the physical layer secure transmission method based on concatenated sequence number modulation, indicating that sequence number modulation with disordered order does not affect the data transmission of legitimate users. Illegal users, unable to obtain consensus information among legitimate users, cannot effectively restore the order disrupted by the disordered sequence number modulation, and therefore cannot correctly demodulate the transmitted information bits. Their bit error rate remains between 0.5 and 0.42, indicating that illegal users cannot demodulate the transmitted information bits.

[0103] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A physical layer secure transmission method based on concatenated sequence number modulation, characterized in that, Secure physical layer transmission is achieved through multiple sequence number modulation concatenation modes, including the following steps: S1. At the transmitting end, each OFDM symbol... Each subcarrier is divided into Each sub-block contains [number] sub-blocks. Each subcarrier and each subblock undergoes independent concatenated sequence number modulation to achieve secure physical layer transmission; S2. According to the subcarrier segmentation method, the input of each OFDM symbol is... Each information bit is divided into corresponding Group, each sub-block corresponds to the following information bits: ,in The information bits are further divided into two groups, the first group One sequence number modulation bit is used for sub-block sequence number modulation from Select from subcarriers One subcarrier transmits modulation symbols, the second group One modulation symbol bit is used for modulation symbol mapping generation. One modulation symbol; S3. Based on the number of modulation symbol bits, use a dimension of... The scrambled sequence number modulation modulates the information bits according to the scrambled sequence number pattern. The obtained modulation symbol bits after sequence number modulation processing are ,in Bit scrambling sequence number pattern The corresponding matrix, This is the information bit vector before bit scrambling sequence number modulation. This is the information bit vector after bit scrambling sequence number modulation; S4. Based on the first group of each sub-block The modulated bit with the sequence number is obtained as the first... The pattern of the activation subcarrier sequence number of each sub-block is as follows: ,in , when At that time, and The elements in the array are arranged in ascending order; According to the second group of each sub-block The information bit vector after modulation of the scrambling sequence number of each modulation symbol bit is... The obtained modulation symbol vector of the i-th sub-block is ; Based on the obtained active subcarrier sequence pattern and modulation symbol vector , obtained the The symbol vector of each sub-block is , where the modulation symbol vector Mapping to the active subcarrier sequence pattern The corresponding subcarrier, i.e. ; S5. Based on the symbol vector dimension, use a dimension size of... Symbol vector perturbation sequence number pattern pair Perform scrambling sequence modulation, and scramble the sequence pattern according to the symbol vector. The symbol vector after scrambling sequence modulation can be obtained. for ,in Disruption of the symbol vector sequence pattern corresponding Matrix; S6, after obtaining all After generating the symbol vectors for each sub-block, then sort them according to their sub-block numbers. The concatenated sequence number modulation transmit symbol vector is obtained by connecting the sub-blocks, and after frequency domain block interleaving, the final frequency domain transmit symbol vector is obtained. ; S7, After transmitting the symbol vector in the frequency domain The inverse Fourier transform yields the time-domain transmitted signal vector. Add a length of to the front end of the transmitted symbol vector. After the cyclic prefix CP is applied, the final time-domain transmitted symbol vector is obtained. After parallel-to-serial conversion and digital-to-analog conversion, it is transmitted to the receiver via the antenna. S8. The time-domain received signal vector received at the receiving end after transmission through the wireless channel is: After removing the cyclic prefix (CP), the received signal vector in the frequency domain is obtained through Fourier transform. Then, a reverse block deinterleaving operation is performed to obtain the frequency domain received signal vector with the original order restored. ; Based on the sub-block grouping method modulated by the transmitter sequence number, the frequency domain received signal vector is divided into corresponding... The number of sub-blocks, then the number of sub-blocks. The frequency domain received signal vector of each sub-block is: ， in The power adjustment factor at the transmitting end. , , and The frequency domain received signal vector before descrambling sequence number modulation processing, frequency domain channel state information, and frequency domain transmitted symbol vector have a mean of 0 and a variance of . The frequency domain Gaussian white noise vector; S9, regarding the first The received signal vectors of each sub-block are descrambled and modulated to restore the original sequence. The frequency domain received signal vector of each sub-block is Then the corresponding channel state information vector at this time is The transmitted symbol vector is The frequency domain Gaussian white noise vector is ; After descrambling sequence number modulation processing, the first... The received signal vector of each sub-block ; S10, based on the first The received signal vector model for each sub-block is used to calculate the most likely transmitted modulation symbol and corresponding metric value for each subcarrier under a given active and inactive state. The most likely transmitted symbol vector under a given active state is: The corresponding metric value is: ， The symbol is sent when given inactivity. The measurement value at this time is: ， in , express Constellation chart; S11, No. The estimated transmit symbol vectors for each sub-block are: ； Based on the obtained transmitted symbol vector estimate Demodulation obtains the sent data. Each sequence number modulation bit and one modulation symbol bit ,in After bit descrambling and sequence number modulation, the original bit order of the information is restored. .

2. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S2, based on the sequence number modulation method, the first group is... 1 modulated bit with sequence number, of which Combination calculation The calculation is performed by rounding down; the second group is... 1 modulation symbol bit, of which The order of the modulated constellation diagram.

3. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S3, the modulation symbol bits are processed by sequence modulation with bit scrambling to scramble the original order of the modulation symbol bits and obtain a new bit sequence. This prevents illegal receiving nodes from obtaining the adjustment symbol bits for each sub-block through demodulation of the received modulation symbols. ; For the Bit scrambling sequence number pattern of each sub-block , among which when From time to time Its corresponding matrix Each row contains only one non-zero element, 1, and its position index is determined by... The corresponding element in, i.e., the first The index of element 1 in the row is The remaining elements are 0.

4. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 3, characterized in that, Bit scrambling sequence number modulation pattern There are a total of available patterns One, can be selected A pattern is used for bit scrambling sequence number modulation, and its sequence number is... ; During information transmission, legitimate users can obtain a set of pseudo-random sequences that are agreed upon by both the sender and receiver through a codebook, channel state information based on legitimate users, or key information transmission methods assisted by artificial noise. ,in .

5. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S4, the number of available active subcarrier sequence number patterns is: The number of active subcarrier sequence number patterns used in sequence modulation is a power of 2, therefore we have An unused, illegally activated subcarrier sequence number pattern.

6. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S5, the dimension is... The symbol vector scrambling sequence number modulation scrambles the order of all modulation symbols in the transmitted symbol vector of the sub-block, and each sub-block performs independent symbol vector scrambling sequence number modulation. No. The symbol vector perturbation sequence number pattern of each sub-block is as follows Its corresponding matrix Each row contains only one non-zero element, 1, whose position index is determined by... The corresponding element in is determined, that is, the first... The index of element 1 in the row is All other elements are 0; Using matrices Left-multiply the transmitted symbol vector The transmitted symbol vector after scrambling order is obtained. This effectively changes the active subcarrier sequence number pattern and the order of modulation symbols in the transmitted symbol vector. After the sequence number is scrambled, the active subcarrier sequence number pattern of some transmitted symbol vectors will be mapped to the illegal active subcarrier sequence number pattern.

7. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 6, characterized in that, Dimensions Symbol vector disturbance sequence number pattern from Choose from the available patterns One is used for symbol vector scrambling sequence number modulation, where ; Legitimate users can obtain consensus information through a codebook, channel state information based on legitimate users, or artificial noise-assisted key information transmission, using a set of consensus pseudo-random sequences. To achieve scrambled sequence number modulation and descrambled sequence number modulation among legitimate users, wherein... .

8. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S9, the received signal vector and channel estimation vector of each sub-block are left-multiplied by the inverse of the modulation matrix of the corresponding symbol vector scrambling sequence number. The original sequence is restored, and after descrambling sequence number modulation processing, the received signal vector model with the original sequence restored is obtained.

9. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S10, the orthogonality of subcarriers in OFDM is utilized to calculate the most likely symbol to be transmitted and the corresponding metric value for each subcarrier under a given activation and deactivation condition, which is used to make a decision on the transmitted symbol vector based on the entire sub-block.

10. The physical layer secure transmission method based on concatenated sequence number modulation according to claim 1, characterized in that, In step S11, a traversal search is performed based on the active subcarrier sequence number pattern of the sub-block and the most likely transmitted symbol obtained under active and inactive conditions for each subcarrier. The demodulation yields the modulation symbol bit sequence. Then, in the bit descrambling sequence modulation, the inverse matrix of the bit scrambling sequence modulation matrix is ​​multiplied by the left. This restores the original order of the sequence number modulation bit sequence.

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