A non-sequence orthogonal computation method for spread spectrum transmission

Abstract

A non-sequential orthogonal computational spread spectrum transmission method is disclosed, belonging to the field of wireless communication technology. This invention solves the problem of poor anti-interference capability in existing spread spectrum transmission methods. This invention uses unitary matrix computation for spread spectrum, enabling different users to transmit simultaneous, same-frequency orthogonal spread spectrum signals. This gives the method a significant advantage in multiple access applications compared to traditional code spread spectrum methods. Furthermore, the unitary matrix-based spread spectrum design allows for greater freedom in power spectrum control of the spread spectrum signal. Compared to the code length limitations in existing code design methods, computational spread spectrum can easily control the spread spectrum bandwidth and gain by modifying the dimensions of the unitary matrix. Compared to traditional code sequence spread spectrum methods, the spread spectrum system of this invention has stronger anti-interference capability and lower power spectral density. This invention can be applied to the field of wireless communication technology.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and specifically relates to a spread spectrum transmission method. Background Technology

[0002] In the field of wireless communication technology, spread spectrum technology is a widely researched and applied link performance enhancement technique. It improves system performance by broadening the spectrum of the transmitted signal using pseudo-random sequences with good correlation characteristics, offering resistance to narrowband interference, multipath interference, and human interference. Furthermore, in secure communication scenarios, it makes the signal difficult for eavesdroppers to detect in background noise. However, the anti-interference capability of existing spread spectrum transmission methods remains relatively poor and needs further improvement. Moreover, in multiple access communication systems, existing direct sequence spread spectrum technology suffers from significant inter-user interference due to the cross-correlation between different code sequences. As the number of multiple access users increases, the impact of mutual interference on communication quality also increases, resulting in a much greater inter-user multiple access interference in code division multiple access systems based on direct sequence spread spectrum compared to other orthogonal multiple access communication systems. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of poor anti-interference capability of existing spread spectrum transmission methods, and to propose a non-sequence orthogonal computation spread spectrum transmission method.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] A non-sequence orthogonal computation method for spread spectrum transmission, the method specifically includes the following steps:

[0006] At the launch end

[0007] Step A1: After constellation modulation of the source bit data stream, a baseband complex data sequence is obtained. The m-th element in the baseband complex data sequence is denoted as x. m ;

[0008] Each element in the baseband complex data sequence is extended into a sequence of length K by padding with zeros, and x is then... m The corresponding extended sequence is denoted as {x} m (0),x m (1),…,x m (K-1)},x m (0),x m (1),…,x m (K-1) represent x m The corresponding extended sequence contains the 1st, 2nd, ..., Kth elements; the extended sequence {x} m (0),x m(1),…,x m The element x in (K-1)} m (u)=x m All other elements are 0, and u represents element x. m The extended sequence {x} obtained by zero-padding m (0),x m (1),…,x m The position in (K-1)};

[0009] Step A2: For the m-th element x in the baseband complex data sequence m , will x m The vector formed by the elements in the corresponding extended sequence is denoted as The superscript T represents transpose, which transposes the vector. Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation.

[0010]

[0011] in, x′ m (0),x′ m (1),…,x′ m (K-1) are respectively The first, second, ..., Kth elements in the matrix; the orthogonal spreading matrix T = [t0, ..., tk]. k ,…,t K-1 ],t0,…,t k ,…,t K-1 Let t represent the 1st column, ..., the (k+1)th column, ..., the Kth column in the orthogonal spreading matrix T. u This refers to the (u+1)th column in the orthogonal spreading matrix T;

[0012] Step A3: The vector obtained in step A2 Mapped onto N subcarriers, the resulting sequence is obtained, where N>K;

[0013] Then perform IFFT on the mapped sequence to obtain the time-domain baseband signal sequence to be transmitted;

[0014] Step A4: The time-domain baseband signal sequence to be transmitted obtained in step A3 is digitally filtered and shaped, and then digital-to-analog converted to obtain an analog signal; the obtained analog signal is then up-converted, and the up-converted signal is transmitted to the channel.

[0015] At the receiving end

[0016] Step A5: Receive the signal transmitted from the transmitter in the channel, and perform down-conversion, analog-to-digital conversion and matched filtering on the received signal in sequence to obtain the time-domain baseband digital signal.

[0017] Step A6: Perform FFT on the time-domain baseband digital signal obtained in step A5 to obtain the frequency-domain baseband digital signal r(n);

[0018] Step A7: Process the frequency domain baseband digital signal r(n) according to the reverse process of the mapping method in step A3, and extract the orthogonal spreading vector of length K.

[0019] Step A8: Utilize orthogonal spreading vectors Obtain the judgment value Wherein, the superscript H represents the conjugate transpose;

[0020] Step A9: For each element in the baseband complex data sequence, execute steps A2 to A8 to demodulate and receive the information.

[0021] Furthermore, the orthogonal spreading matrix T has a dimension of 2. L ×2 L ;

[0022] When L=1, let the orthogonal spreading matrix

[0023] When L≥2, let the orthogonal spreading matrix

[0024] in,[·] F1 For matrix operations, a and b are:

[0025]

[0026] Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

[0027] Furthermore, the matrix operation [·] F1 for:

[0028]

[0029] Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M.

[0030] Furthermore, in step A3, the vector obtained in step A2 is... The sequence is mapped onto N subcarriers; the specific process is as follows:

[0031]

[0032] Where s(n) is the (n+1)th element in the mapped sequence, x′ m (n-1) is a vector The nth element in, x′ m (n-N+K) is a vector The (n-N+K+1)th element in the array.

[0033] A non-sequence orthogonal computation method for spread spectrum transmission, the method specifically includes the following steps:

[0034] At the user sending end

[0035] Step B1: For the i-th user in the system, after constellation modulation of the source bit data stream of the i-th user, the baseband complex data sequence corresponding to the i-th user is obtained. The m-th element in the baseband complex data sequence corresponding to the i-th user is denoted as...

[0036] Step B2: Expand each element of the baseband complex data sequence corresponding to the i-th user into a sequence of length K by padding with zeros. The corresponding extended sequence is denoted as They are respectively The corresponding 1st, 2nd, ..., Kth elements in the extended sequence; extended sequence elements in All other elements are 0, and u(i) represents the element in the i-th user. The extended sequence obtained by zero padding The position in the middle;

[0037] Step B3: For the m-th element in the baseband complex data sequence corresponding to the i-th user, by... The vector composed of the elements in the corresponding extended sequence for:

[0038]

[0039] The superscript T represents transpose;

[0040] vector Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation. for:

[0041]

[0042] in, They are respectively The first, second, ..., Kth elements in the matrix; the orthogonal spreading matrix T = [t0, ..., tk]. k ,…,t K-1 ],t0,…,t k ,…,t K-1 Let t represent the 1st column, ..., the (k+1)th column, ..., the Kth column in the orthogonal spreading matrix T. u(i) This refers to the (i)+1th column of the orthogonal spreading matrix T;

[0043] Step B4: The vector obtained in step B3 The sequence is mapped onto N subcarriers, where N > K.

[0044] Perform an IFFT on the mapped sequence to obtain The corresponding time-domain baseband signal sequence to be transmitted;

[0045] Step B5, for The corresponding time-domain baseband signal sequence to be transmitted is sequentially digitally filtered and shaped, and then digital-to-analog converted to obtain an analog signal; the obtained analog signal is then up-converted, and the processed signal is transmitted to the channel;

[0046] Step B6: Process each element in the baseband complex data sequence corresponding to the i-th user according to steps B3 to B5;

[0047] Step B7: Process each user in the system according to steps B1 to B6;

[0048] At the base station receiver

[0049] Step C1: The base station receiver performs down-conversion processing on the received signal, and then performs analog-to-digital conversion and matched filtering on the down-converted signal to obtain a time-domain baseband digital signal.

[0050] Step C2: Perform FFT on the time-domain baseband digital signal obtained in step C1 to obtain the frequency-domain baseband digital signal r(n);

[0051] Step C3: Process the frequency domain baseband digital signal r(n) obtained in step C2 according to the reverse process of the mapping method in step B4, and extract an orthogonal spreading vector of length K.

[0052] Where M′ is the length of the baseband complex data sequence for each user;

[0053] Step C4: Using the orthogonal spreading vectors in step C3, obtain the decision value of each element in the baseband complex data sequence of each user, thereby realizing the demodulation and reception of information from different users;

[0054] For orthogonal spreading vectors

[0055]

[0056] in, Let H be the decision value of the m-th element in the baseband complex data sequence of the i-th user, where the superscript H represents the conjugate transpose.

[0057] Furthermore, the orthogonal spreading matrix T has a dimension of 2. L ×2 L ;

[0058] When L=1, let the orthogonal spreading matrix

[0059] When L≥2, let the orthogonal spreading matrix

[0060] in,[·] F1 This refers to matrix operations, specifically:

[0061]

[0062] Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M;

[0063] a and b are:

[0064]

[0065] Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

[0066] Furthermore, the vector obtained in step B3 Mapped onto N subcarriers, the mapped sequence is obtained; specifically:

[0067]

[0068] Where s(n) is the (n+1)th element in the mapped sequence, Let n be the nth element in the result of the linear transformation of the matrix. It is the (n-N+K+1)th element in the result of the linear transformation of the matrix.

[0069] A non-sequence orthogonal computation method for spread spectrum transmission, the method specifically includes the following steps:

[0070] At the base station transmitter

[0071] Step D1: Perform constellation modulation on the source bit data stream to be sent to the i-th user in the system to obtain the baseband complex data sequence to be sent to the i-th user in the system. Denote the m-th element in the baseband complex data sequence to be sent to the i-th user as...

[0072] Step D2: Expand each element of the baseband complex data sequence to be sent to the i-th user in the system into a sequence of length K by padding with zeros. The corresponding extended sequence is denoted as They are respectively The corresponding 1st, 2nd, ..., Kth elements in the extended sequence; extended sequence elements in All other elements are 0, and u(i) represents the element to be sent to the i-th user in the system. The extended sequence obtained by zero padding The position in the middle;

[0073] Step D3: Process the source bit data stream to be sent to each user in the system according to steps D1 to D2 respectively;

[0074] Step D4: Construct a vector based on the extended sequence corresponding to the m-th element in the baseband complex data sequence sent to each user.

[0075]

[0076] Where K′ is the number of users in the system;

[0077] vector Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation.

[0078]

[0079] Among them, t u(i) The u(i)+1th column in the orthogonal spreading matrix T; the resulting vector Mapping onto N subcarriers yields the mapped sequence, where N > K;

[0080] Then perform IFFT on the mapped sequence to obtain the time-domain baseband signal sequence to be transmitted corresponding to the m-th element in each baseband complex data sequence;

[0081] The obtained time-domain baseband signal sequence to be transmitted is sequentially subjected to digital filtering shaping, digital-to-analog conversion, and up-conversion processing before the processed signal is transmitted to the channel.

[0082] Similarly, the extended sequences corresponding to other elements are processed;

[0083] At the user receiving end

[0084] Step E1: The receiver receives the signal transmitted by the base station transmitter. The i-th user in the system performs down-conversion, analog-to-digital conversion and matched filtering on the received signal in sequence to obtain the time-domain baseband digital signal.

[0085] Step E2: Perform FFT on the time-domain baseband digital signal obtained in step E1 to obtain the frequency-domain baseband digital signal r(n);

[0086] Step E3: Following the inverse process of the mapping method in step D4, extract the signal from the frequency domain baseband digital signal r(n). The corresponding orthogonal spreading vector of length K M′ is the total number of elements in the baseband complex data sequence of the i-th user;

[0087] Step E4: Obtain the decision value based on the orthogonal spreading vector in step E3, and realize the demodulation and reception of the i-th user information;

[0088]

[0089] The superscript H indicates the conjugate transpose. Let M' be the decision value corresponding to the m-th element in the baseband complex data sequence of the i-th user, where m = 1, 2, ..., M'.

[0090] Step E5: Each user in the system executes the process from steps E1 to E4 to demodulate and receive each user's information.

[0091] Furthermore, the orthogonal spreading matrix T has a dimension of 2. L ×2 L ;

[0092] When L=1, let the orthogonal spreading matrix

[0093] When L≥2, let the orthogonal spreading matrix

[0094] in,[·] F1 This refers to matrix operations, specifically:

[0095]

[0096] Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M;

[0097] a and b are:

[0098]

[0099] Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

[0100] Furthermore, the mapped sequence is:

[0101]

[0102] Where s(n) is the (n+1)th element in the mapped sequence, x′ m (n-1) is the nth element in the result of the linear transformation of the matrix, x′ m (n-N+K) represents the (n-N+K+1)th element in the result of the linear transformation of the matrix.

[0103] The beneficial effects of this invention are:

[0104] This invention utilizes unitary matrix calculations for spread spectrum generation, enabling different users to transmit simultaneous, orthogonal spread spectrum signals at the same frequency. This gives the method a significant advantage in multiple access applications compared to traditional code spread spectrum methods. Furthermore, the unitary matrix-based spread spectrum design allows for greater freedom in power spectrum control. Compared to the limitations of code length in existing code design methods, computation-based spread spectrum allows for convenient control of the spread spectrum bandwidth and gain by modifying the dimensions of the unitary matrix. Compared to traditional code sequence spread spectrum methods, the spread spectrum system of this invention exhibits stronger anti-interference capabilities and lower power spectral density. Attached Figure Description

[0105] Figure 1 This is a block diagram of the spread spectrum communication system according to specific implementation method one;

[0106] Figure 2 This is a time-domain waveform diagram of an orthogonal spread spectrum signal obtained through a type of orthogonal spread spectrum matrix defined in this invention;

[0107] Figure 3(a) is a block diagram of the user transmitter system of the spread spectrum communication system according to specific implementation method five;

[0108] Figure 3(b) is a block diagram of the base station receiver system of the spread spectrum communication system in specific implementation five;

[0109] Figure 3(c) is a block diagram of the base station transmitter system of the spread spectrum communication system in specific implementation method eight;

[0110] Figure 3(d) is a block diagram of the user receiver system of the spread spectrum communication system according to specific implementation method eight.

[0111] Figure 4 This is a simulation comparison chart of the communication bit error rate between the method of this invention and the traditional CDMA system. Detailed Implementation

[0112] Specific Implementation Method 1: Combination Figure 1 This embodiment describes a non-sequence orthogonal computation spread spectrum transmission method, which specifically includes the following steps:

[0113] At the launch end

[0114] Step A1: After constellation modulation of the source bit data stream, a baseband complex data sequence is obtained. The m-th element in the baseband complex data sequence is denoted as x. m ;

[0115] Each element in the baseband complex data sequence is extended into a sequence of length K by padding with zeros, and x is then... m The corresponding extended sequence is denoted as {x} m (0),x m (1),…,x m (K-1)},x m (0),x m (1),…,x m (K-1) represent x m The corresponding extended sequence contains the 1st, 2nd, ..., Kth elements; the extended sequence {x} m (0),x m (1),…,x m The element x in (K-1)} m (u)=x m All other elements are 0, and u represents element x. m The extended sequence {x} obtained by zero-padding m (0),x m (1),…,x m The position in (K-1)};

[0116] The total length of the extended sequence corresponding to each element is K times the length of the source sequence;

[0117] Step A2: For the m-th element x in the baseband complex data sequence m , will x m The vector formed by the elements in the corresponding extended sequence is denoted as The superscript T represents transpose, which transposes the vector. Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation.

[0118]

[0119] in, x′ m (0),x′ m (1),…,x′ m (K-1) are respectively The first, second, ..., Kth elements in the matrix; the orthogonal spreading matrix T = [t0, ..., tk]. k ,…,t K-1 ],t0,…,t k ,…,t K-1 Let t represent the 1st column, ..., the (k+1)th column, ..., the Kth column in the orthogonal spreading matrix T. u This refers to the (u+1)th column in the orthogonal spreading matrix T;

[0120] Step A3: The vector obtained in step A2 Mapped onto N subcarriers, the resulting sequence is obtained, where N>K;

[0121] Then perform IFFT on the mapped sequence to obtain the time-domain baseband signal sequence to be transmitted;

[0122] Step A4: The time-domain baseband signal sequence to be transmitted obtained in step A3 is digitally filtered and shaped, and then digital-to-analog converted to obtain an analog signal; the obtained analog signal is then up-converted, and the up-converted signal is transmitted to the channel.

[0123] At the receiving end

[0124] Step A5: Receive the signal transmitted from the transmitter in the channel, and perform down-conversion, analog-to-digital conversion and matched filtering on the received signal in sequence to obtain the time-domain baseband digital signal.

[0125] Step A6: Perform FFT on the time-domain baseband digital signal obtained in step A5 to obtain the frequency-domain baseband digital signal r(n);

[0126] Step A7: Process the frequency domain baseband digital signal r(n) according to the reverse process of the mapping method in step A3, and extract the orthogonal spreading vector of length K.

[0127] Step A8: Utilize orthogonal spreading vectors Obtain the judgment value Wherein, the superscript H represents the conjugate transpose;

[0128] Step A9: For each element in the baseband complex data sequence, execute steps A2 to A8 to demodulate and receive the information.

[0129] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the dimension of the orthogonal spreading matrix T is 2. L ×2 L ;

[0130] When L=1, let the orthogonal spreading matrix

[0131] When L≥2, let the orthogonal spreading matrix

[0132] in,[·] F1 For matrix operations, a and b are:

[0133]

[0134] Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

[0135] The other steps and parameters are the same as in Specific Implementation Method 1.

[0136] Figure 2 This is the time-domain waveform of the orthogonal spread spectrum signal obtained through an orthogonal spreading matrix. Besides satisfying the fundamental requirement that it is a unitary matrix, the orthogonal spreading matrix also possesses the following special properties:

[0137] (1) The magnitude of each element of the matrix is ​​1, so the spectrum of the time-domain spread spectrum signal obtained by IFFT is flat;

[0138] (2) The time-domain spread spectrum signal waveform obtained based on this matrix has a PAPR of 2 when N≥8, which is beneficial for implementation under existing RF hardware schemes;

[0139] (3) A type of matrix with scalable dimensions is defined by the above method, and the spreading bandwidth and spreading gain can be controlled by changing the size of the matrix dimension.

[0140] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the matrix operation [·] F1 for:

[0141]

[0142] Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M.

[0143] Matrix operations are equivalent to transforming matrix T L-1 Each column of elements is flipped while the rows remain unchanged.

[0144] Other steps and parameters are the same as in specific implementation method one or two.

[0145] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that, in step A3, the vector obtained in step A2 is... The sequence is mapped onto N subcarriers; the specific process is as follows:

[0146]

[0147] Where s(n) is the (n+1)th element in the mapped sequence, x′ m (n-1) is a vector The nth element in, x′ m (n-N+K) is a vector The (n-N+K+1)th element in the array.

[0148] The other steps and parameters are the same as those in one of the specific implementation methods one to three.

[0149] Specific Implementation Method Five: This implementation method is described in conjunction with Figures 3(a) and 3(b). The non-sequence orthogonal calculation spread spectrum transmission method described in this implementation method specifically includes the following steps:

[0150] At the user sending end

[0151] Step B1: For the i-th user in the system, after constellation modulation of the source bit data stream of the i-th user, the baseband complex data sequence corresponding to the i-th user is obtained. The m-th element in the baseband complex data sequence corresponding to the i-th user is denoted as...

[0152] Step B2: Expand each element of the baseband complex data sequence corresponding to the i-th user into a sequence of length K by padding with zeros. The corresponding extended sequence is denoted as They are respectively The corresponding 1st, 2nd, ..., Kth elements in the extended sequence; extended sequence elements in All other elements are 0, and u(i) represents the element in the i-th user. The extended sequence obtained by zero padding The position of an element within a user; for each user, there is a corresponding u value. In the extended sequence, the position of an element within a user is its corresponding u value.

[0153] Each user has a different value for parameter u during expansion. That is, when i is different, the value of u is also different. In other words, for each element in the baseband complex data sequence corresponding to the i-th user, their corresponding u values ​​are the same, but the u values ​​corresponding to different users are different. Therefore, the value of K should be selected according to the number of users in the system to ensure that the total number of users in the system is less than or equal to K.

[0154] Step B3: For the m-th element in the baseband complex data sequence corresponding to the i-th user, by... The vector composed of the elements in the corresponding extended sequence for:

[0155]

[0156] The superscript T represents transpose;

[0157] vector Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation. for:

[0158]

[0159] in, They are respectively The first, second, ..., Kth elements in the matrix; the orthogonal spreading matrix T = [t0, ..., tk]. k ,…,t K-1 ],t0,…,t k ,…,t K-1 Let t represent the 1st column, ..., the (k+1)th column, ..., the Kth column in the orthogonal spreading matrix T. u(i) This refers to the (i)+1th column of the orthogonal spreading matrix T;

[0160] Step B4: The vector obtained in step B3 The sequence is mapped onto N subcarriers, where N > K.

[0161] Perform an IFFT on the mapped sequence to obtain The corresponding time-domain baseband signal sequence to be transmitted;

[0162] Step B5, for The corresponding time-domain baseband signal sequence to be transmitted is sequentially digitally filtered and shaped, and then digital-to-analog converted to obtain an analog signal; the obtained analog signal is then up-converted, and the processed signal is transmitted to the channel;

[0163] Step B6: Process each element in the baseband complex data sequence corresponding to the i-th user according to steps B3 to B5;

[0164] Step B7: Process each user in the system according to steps B1 to B6;

[0165] At the base station receiver

[0166] Step C1: The base station receiver performs down-conversion processing on the received signal, and then performs analog-to-digital conversion and matched filtering on the down-converted signal to obtain a time-domain baseband digital signal.

[0167] Step C2: Perform FFT on the time-domain baseband digital signal obtained in step C1 to obtain the frequency-domain baseband digital signal r(n);

[0168] Step C3: Process the frequency domain baseband digital signal r(n) obtained in step C2 according to the reverse process of the mapping method in step B4, and extract an orthogonal spreading vector of length K.

[0169] Where M′ is the length of the baseband complex data sequence for each user;

[0170] Step C4: Using the orthogonal spreading vectors in step C3, obtain the decision value of each element in the baseband complex data sequence of each user, thereby realizing the demodulation and reception of information from different users;

[0171] For orthogonal spreading vectors

[0172]

[0173] in, Let H be the decision value of the m-th element in the baseband complex data sequence of the i-th user, where the superscript H represents the conjugate transpose.

[0174] This implementation method can achieve orthogonal multiple access between different users in a multiple access scenario, avoiding the impact of mutual interference between different users on communication quality.

[0175] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the dimension of the orthogonal spreading matrix T is 2. L ×2 L ;

[0176] When L=1, let the orthogonal spreading matrix

[0177] When L≥2, let the orthogonal spreading matrix

[0178] in,[·] F1 This refers to matrix operations, specifically:

[0179]

[0180] Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M;

[0181] Equivalent to matrix T L-1 Each column of elements is flipped while the rows remain unchanged.

[0182] a and b are:

[0183]

[0184] Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

[0185] The other steps and parameters are the same as in Specific Implementation Method 5.

[0186] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Five or Six in that the vector obtained in step B3 is... Mapped onto N subcarriers, the mapped sequence is obtained; specifically:

[0187]

[0188] Where s(n) is the (n+1)th element in the mapped sequence, Let n be the nth element in the result of the linear transformation of the matrix. It is the (n-N+K+1)th element in the result of the linear transformation of the matrix.

[0189] The other steps and parameters are the same as in specific implementation methods five or six.

[0190] Detailed Implementation Method 8: This implementation method is described in conjunction with Figures 3(c) and 3(d). The non-sequence orthogonal calculation spread spectrum transmission method described in this implementation method specifically includes the following steps:

[0191] At the base station transmitter

[0192] Step D1: Perform constellation modulation on the source bit data stream to be sent to the i-th user in the system to obtain the baseband complex data sequence to be sent to the i-th user in the system. Denote the m-th element in the baseband complex data sequence to be sent to the i-th user as...

[0193] Step D2: Expand each element of the baseband complex data sequence to be sent to the i-th user in the system into a sequence of length K by padding with zeros. The corresponding extended sequence is denoted as They are respectively The corresponding 1st, 2nd, ..., Kth elements in the extended sequence; extended sequence elements in All other elements are 0, and u(i) represents the element to be sent to the i-th user in the system. The extended sequence obtained by zero padding The position of the element to be sent to the user in the extended sequence; for each user, there is a corresponding u value.

[0194] Each user has a different value for parameter u during expansion. That is, when i is different, the value of u is also different. In other words, for each element in the baseband complex data sequence corresponding to the i-th user, their corresponding u values ​​are the same, but the u values ​​corresponding to different users are different. Therefore, the value of K should be selected according to the number of users in the system to ensure that the total number of users in the system is less than or equal to K.

[0195] Step D3: Process the source bit data stream to be sent to each user in the system according to steps D1 to D2 respectively;

[0196] Step D4: Construct a vector based on the extended sequence corresponding to the m-th element in the baseband complex data sequence sent to each user.

[0197]

[0198] Where K′ is the number of users in the system;

[0199] vector Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation.

[0200]

[0201] Among them, t u(i) For the u(i)+1th column of the orthogonal spreading matrix T (for The value of u(i) is In the extended sequence obtained by padding with zeros, since each user has a different u value, the u value changes as the i value changes (but for the same user, the u value is the same for each element within that user); the resulting vector Mapping onto N subcarriers yields the mapped sequence, where N > K;

[0202] Then perform IFFT on the mapped sequence to obtain the time-domain baseband signal sequence to be transmitted that corresponds to the m-th element in each baseband complex data sequence.

[0203] The obtained time-domain baseband signal sequence to be transmitted is sequentially subjected to digital filtering shaping, digital-to-analog conversion, and up-conversion processing before the processed signal is transmitted to the channel.

[0204] Similarly, the extended sequences corresponding to other elements are processed;

[0205] At the user receiving end

[0206] Step E1: The receiver receives the signal transmitted by the base station transmitter. The i-th user in the system performs down-conversion, analog-to-digital conversion and matched filtering on the received signal in sequence to obtain the time-domain baseband digital signal.

[0207] Step E2: Perform FFT on the time-domain baseband digital signal obtained in step E1 to obtain the frequency-domain baseband digital signal r(n);

[0208] Step E3: Following the inverse process of the mapping method in step D4, extract the signal from the frequency domain baseband digital signal r(n). The corresponding orthogonal spreading vector of length K M′ is the total number of elements in the baseband complex data sequence of the i-th user;

[0209] Step E4: Obtain the decision value based on the orthogonal spreading vector in step E3, and realize the demodulation and reception of the i-th user information;

[0210]

[0211] The superscript H indicates the conjugate transpose. Let M' be the decision value corresponding to the m-th element in the baseband complex data sequence of the i-th user, where m = 1, 2, ..., M'.

[0212] Step E5: Each user in the system executes the process from steps E1 to E4 to demodulate and receive each user's information.

[0213] This implementation method can achieve orthogonal multiple access between different users in a multiple access scenario, avoiding the impact of mutual interference between different users on communication quality.

[0214] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Eight in that the dimension of the orthogonal spreading matrix T is 2. L ×2 L ;

[0215] When L=1, let the orthogonal spreading matrix

[0216] When L≥2, let the orthogonal spreading matrix

[0217] in,[·] F1 This refers to matrix operations, specifically:

[0218]

[0219] Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M;

[0220] Equivalent to matrix T L-1 Each column of elements is flipped while the rows remain unchanged;

[0221] a and b are:

[0222]

[0223] Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

[0224] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Eight or Nine in that the mapped sequence is as follows:

[0225]

[0226] Where s(n) is the (n+1)th element in the mapped sequence, x′ m (n-1) is the nth element in the result of the linear transformation of the matrix, x′ m (n-N+K) represents the (n-N+K+1)th element in the result of the linear transformation of the matrix.

[0227] The other steps and parameters are the same as in specific implementation method eight or nine.

[0228] Figure 4This paper presents a performance simulation comparison between the multiple access system based on the non-sequential orthogonal computation spread spectrum transmission method proposed in this invention and a traditional CDMA system. The CDMA system uses a Gold sequence for spread spectrum. The simulation parameters include a spread factor of 128 and an AWGN channel. It can be seen that the bit error rate performance of the traditional CDMA system decreases with the increase in the number of users. However, the method of this invention maintains orthogonality between different users before and after spread spectrum, so an increase in the number of users does not deteriorate the bit error rate performance. Therefore, the non-sequential orthogonal computation spread spectrum transmission method proposed in this invention not only has the advantage of strong anti-interference capability in terms of mechanism, but also has a mechanism advantage over the traditional CDMA system in multi-user scenarios.

[0229] The above examples of the present invention are merely illustrative of the computational model and process of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A non-sequence orthogonal computation method for spread spectrum transmission, characterized in that, The method specifically includes the following steps: At the launch end Step A1: After constellation modulation of the source bit data stream, a baseband complex data sequence is obtained. The m-th element in the baseband complex data sequence is denoted as x. m ; Each element in the baseband complex data sequence is extended into a sequence of length K by padding with zeros, and x is then... m The corresponding extended sequence is denoted as {x} m (0),x m (1),…,x m (K-1)},x m (0),x m (1),…,x m (K-1) represent x m The corresponding extended sequence contains the 1st, 2nd, ..., Kth elements; the extended sequence {x} m (0),x m (1),…,x m The element x in (K-1)} m (u)=x m All other elements are 0, and u represents element x. m The extended sequence {x} obtained by zero-padding m (0),x m (1),…,x m The position in (K-1)}; Step A2: For the m-th element x in the baseband complex data sequence m , will x m The vector formed by the elements in the corresponding extended sequence is denoted as The superscript T represents transpose, which transposes the vector. Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation. in, x′ m (0),x′ m (1),…,x′ m (K-1) are respectively The first, second, ..., Kth elements in the matrix; the orthogonal spreading matrix T = [t0, ..., tk]. k ,…,t K-1 ],t0,…,t k ,…,t K-1 Let t represent the 1st column, ..., the (k+1)th column, ..., the Kth column in the orthogonal spreading matrix T. u This refers to the (u+1)th column in the orthogonal spreading matrix T; Step A3: The vector obtained in step A2 Mapped onto N subcarriers, the resulting sequence is obtained, where N>K; Then perform IFFT on the mapped sequence to obtain the time-domain baseband signal sequence to be transmitted; Step A4: The time-domain baseband signal sequence to be transmitted obtained in step A3 is digitally filtered and shaped, and then digital-to-analog converted to obtain an analog signal; the obtained analog signal is then up-converted, and the up-converted signal is transmitted to the channel. At the receiving end Step A5: Receive the signal transmitted from the transmitter in the channel, and perform down-conversion, analog-to-digital conversion and matched filtering on the received signal in sequence to obtain the time-domain baseband digital signal. Step A6: Perform FFT on the time-domain baseband digital signal obtained in step A5 to obtain the frequency-domain baseband digital signal r(n); Step A7: Process the frequency domain baseband digital signal r(n) according to the reverse process of the mapping method in step A3, and extract the orthogonal spreading vector of length K. Step A8: Utilize orthogonal spreading vectors Obtain the judgment value Wherein, the superscript H represents the conjugate transpose; Step A9: For each element in the baseband complex data sequence, execute steps A5 to A8 to demodulate and receive the information.

2. The non-sequence orthogonal computation spread spectrum transmission method according to claim 1, characterized in that, The orthogonal spreading matrix T has a dimension of 2. L ×2 L ; When L=1, let the orthogonal spreading matrix When L≥2, let the orthogonal spreading matrix in,[·] F1 For matrix operations, a and b are: Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

3. The non-sequence orthogonal computation spread spectrum transmission method according to claim 2, characterized in that, The matrix operations [·] F1 for: Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M.

4. The non-sequence orthogonal computation spread spectrum transmission method according to claim 3, characterized in that, In step A3, the vector obtained in step A2 is... The sequence is mapped onto N subcarriers; the specific process is as follows: Where s(n) is the (n+1)th element in the mapped sequence, x′ m (n-1) is a vector The nth element in, x′ m (n-N+K) is a vector The (n-N+K+1)th element in the array.

5. A non-sequence orthogonal computation method for spread spectrum transmission, characterized in that, The method specifically includes the following steps: At the user sending end Step B1: For the i-th user in the system, after constellation modulation of the source bit data stream of the i-th user, the baseband complex data sequence corresponding to the i-th user is obtained. The m-th element in the baseband complex data sequence corresponding to the i-th user is denoted as... Step B2: Expand each element of the baseband complex data sequence corresponding to the i-th user into a sequence of length K by padding with zeros. The corresponding extended sequence is denoted as They are respectively The corresponding 1st, 2nd, ..., Kth elements in the extended sequence; extended sequence elements in All other elements are 0, and u(i) represents the element in the i-th user. The extended sequence obtained by zero padding The position in the middle; Step B3: For the m-th element in the baseband complex data sequence corresponding to the i-th user, by... The vector composed of the elements in the corresponding extended sequence for: The superscript T represents transpose; vector Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation. for: in, They are respectively The first, second, ..., Kth elements in the matrix; the orthogonal spreading matrix T = [t0, ..., tk]. k ,…,t K-1 ],t0,…,t k ,…,t K-1 Let t represent the 1st column, ..., the (k+1)th column, ..., the Kth column in the orthogonal spreading matrix T. u(i) This refers to the (i)+1th column of the orthogonal spreading matrix T; Step B4: The vector obtained in step B3 The sequence is mapped onto N subcarriers, where N > K. Perform an IFFT on the mapped sequence to obtain The corresponding time-domain baseband signal sequence to be transmitted; Step B5, for The corresponding time-domain baseband signal sequence to be transmitted is sequentially digitally filtered and shaped, and then digital-to-analog converted to obtain an analog signal; the obtained analog signal is then up-converted, and the processed signal is transmitted to the channel; Step B6: Process each element in the baseband complex data sequence corresponding to the i-th user according to steps B3 to B5; Step B7: Process each user in the system according to steps B1 to B6; At the base station receiver Step C1: The base station receiver performs down-conversion processing on the received signal, and then performs analog-to-digital conversion and matched filtering on the down-converted signal to obtain a time-domain baseband digital signal. Step C2: Perform FFT on the time-domain baseband digital signal obtained in step C1 to obtain the frequency-domain baseband digital signal r(n); Step C3: Process the frequency domain baseband digital signal r(n) obtained in step C2 according to the reverse process of the mapping method in step B4, and extract an orthogonal spreading vector of length K. Where M′ is the length of the baseband complex data sequence for each user; Step C4: Using the orthogonal spreading vectors in step C3, obtain the decision value of each element in the baseband complex data sequence of each user, thereby realizing the demodulation and reception of information from different users; For orthogonal spreading vectors in, Let H be the decision value of the m-th element in the baseband complex data sequence of the i-th user, where the superscript H represents the conjugate transpose.

6. The non-sequence orthogonal computation spread spectrum transmission method according to claim 5, characterized in that, The orthogonal spreading matrix T has a dimension of 2. L ×2 L ; When L=1, let the orthogonal spreading matrix When L≥2, let the orthogonal spreading matrix in,[·] F1 This refers to matrix operations, specifically: Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M; a and b are: Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

7. The non-sequence orthogonal computation spread spectrum transmission method according to claim 6, characterized in that, The vector obtained in step B3 Mapped onto N subcarriers, the mapped sequence is obtained; specifically: Where s(n) is the (n+1)th element in the mapped sequence, Let n be the nth element in the result of the linear transformation of the matrix. It is the (n-N+K+1)th element in the result of the linear transformation of the matrix.

8. A non-sequence orthogonal computation method for spread spectrum transmission, characterized in that, The method specifically includes the following steps: At the base station transmitter Step D1: Perform constellation modulation on the source bit data stream to be sent to the i-th user in the system to obtain the baseband complex data sequence to be sent to the i-th user in the system. Denote the m-th element in the baseband complex data sequence to be sent to the i-th user as... Step D2: Expand each element of the baseband complex data sequence to be sent to the i-th user in the system into a sequence of length K by padding with zeros. The corresponding extended sequence is denoted as They are respectively The corresponding 1st, 2nd, ..., Kth elements in the extended sequence; extended sequence elements in All other elements are 0, and u(i) represents the element to be sent to the i-th user in the system. The extended sequence obtained by zero padding The position in the middle; Step D3: Process the source bit data stream to be sent to each user in the system according to steps D1 to D2 respectively; Step D4: Construct a vector based on the extended sequence corresponding to the m-th element in the baseband complex data sequence sent to each user. Where K′ is the number of users in the system; vector Multiplying by an orthogonal spreading matrix T on the left yields the result after a linear matrix transformation. Among them, t u(i) This refers to the (i)+1th column of the orthogonal spreading matrix T; The resulting vector Mapping onto N subcarriers yields the mapped sequence, where N > K; Then perform IFFT on the mapped sequence to obtain the time-domain baseband signal sequence to be transmitted corresponding to the m-th element in each baseband complex data sequence; The obtained time-domain baseband signal sequence to be transmitted is sequentially subjected to digital filtering shaping, digital-to-analog conversion, and up-conversion processing before the processed signal is transmitted to the channel. Similarly, the extended sequences corresponding to other elements are processed; At the user receiving end Step E1: The receiver receives the signal transmitted by the base station transmitter. The i-th user in the system performs down-conversion, analog-to-digital conversion and matched filtering on the received signal in sequence to obtain the time-domain baseband digital signal. Step E2: Perform FFT on the time-domain baseband digital signal obtained in step E1 to obtain the frequency-domain baseband digital signal r(n); Step E3: Following the inverse process of the mapping method in step D4, extract the signal from the frequency domain baseband digital signal r(n). The corresponding orthogonal spreading vector of length K M′ is the total number of elements in the baseband complex data sequence of the i-th user; Step E4: Obtain the decision value based on the orthogonal spreading vector in step E3, and realize the demodulation and reception of the i-th user information; The superscript H indicates the conjugate transpose. Let M' be the decision value corresponding to the m-th element in the baseband complex data sequence of the i-th user, where m = 1, 2, ..., M'. Step E5: Each user in the system executes the process from steps E1 to E4 to demodulate and receive each user's information.

9. The non-sequence orthogonal computation spread spectrum transmission method according to claim 8, characterized in that, The orthogonal spreading matrix T has a dimension of 2. L ×2 L ; When L=1, let the orthogonal spreading matrix When L≥2, let the orthogonal spreading matrix in,[·] F1 This refers to matrix operations, specifically: Where M = 2 L-1 , t i′,j′ For T L-1 The element in the i′ row and j′ column, i′=1,2,…,M, j′=1,2,…,M; a and b are: Where i is the imaginary unit, and θ is any real number in the range [0, 2π).

10. The non-sequence orthogonal computation spread spectrum transmission method according to claim 9, characterized in that, The mapped sequence is: Where s(n) is the (n+1)th element in the mapped sequence, x′ m (n-1) is the nth element in the result of the linear transformation of the matrix, x′ m (n-N+K) represents the (n-N+K+1)th element in the result of the linear transformation of the matrix.

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