Hybrid precoding method and equipment for OFDM time-modulated antenna array systems

Abstract

This invention provides a hybrid precoding method and apparatus for a time-modulated antenna array (OFDM) system. The method includes: generating hybrid precoding parameters based on channel state information, including the pulse duty cycle, start time, and baseband precoding matrix of the single-pole double-throw (SPDT) RF switch of the time-modulated antenna array; performing baseband precoding processing on user data using a baseband precoder; generating an active interference cancellation signal, superimposing it with the baseband precoding signal, and then performing OFDM modulation; and controlling the antenna array to transmit signals via the SPDT RF switch to suppress sideband radiated interference. This invention employs regularization processing to achieve an effective trade-off between beamforming gain and avoiding sideband radiated interference. Adjusting the pulse start time of the SPDT RF switch controls the phase of the maximum harmonic interference, minimizing the statistically significant maximum harmonic interference. Furthermore, by introducing an active interference cancellation signal, other higher-order harmonic interference caused by subcarriers is further canceled.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a hybrid precoding method and device for a time-modulated antenna array (OFDM) system. Background Technology

[0002] Time-modulated antenna arrays (TMAAs) use periodic pulse signals to control radio frequency switches to generate array beam pointing, offering advantages over traditional phase shifter solutions such as low cost, low insertion loss, and miniaturized feed networks. However, harmonic interference from periodic switching can cause sideband radiation. Most current related technologies for suppressing sideband radiation are based on narrowband wireless communication. For broadband multicarrier communication, existing solutions overcome harmonic interference between subcarriers by using idle subchannels. In reality, TMAAs have abundant high-order harmonic components, and idle subchannels cannot completely eliminate sideband radiation. Furthermore, too many idle subchannels can lead to a decrease in system bandwidth utilization. Therefore, developing a hybrid precoding method and device for time-modulated antenna array (OFDM) systems to effectively overcome the shortcomings of the aforementioned technologies has become a pressing technical problem in the industry. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, embodiments of the present invention provide a hybrid precoding method and device for a time-modulated antenna array (OFDM) system.

[0004] In a first aspect, embodiments of the present invention provide a hybrid precoding method for a time-modulated antenna array (OFDM) system, comprising: generating hybrid precoding parameters based on channel state information, including the pulse duty cycle, start time, and baseband precoding matrix of a single-pole double-throw (SPD) RF switch of the time-modulated antenna array; performing baseband precoding processing on user data using a baseband precoder; generating an active interference cancellation signal, superimposing it with the baseband precoding signal, and then performing OFDM modulation; and controlling the antenna array to transmit signals using a SPD RF switch to suppress sideband radiated interference.

[0005] Based on the above method embodiments, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this embodiment of the invention includes generating hybrid precoding parameters based on channel state information, comprising:

[0006] Step 1: Construct the transmission sub-channel frequency response matrix T based on the channel frequency response matrix H, and then... And extract the eigenvector group G corresponding to its first L largest eigenvalues;

[0007] Step 2: Solve the SOCP optimization problem for all column vectors g[i], i∈[0,L-1] of the feature vector group G:

[0008]

[0009] Step 3, according to g RF The results of [i], i∈[0,L-1] are normalized to obtain the fundamental frequency simulation precoding matrix. And calculate the pulse duty cycle for each single-pole double-throw switch.

[0010]

[0011] Step 4: Based on the fundamental frequency analog precoding matrix Calculate the digital baseband precoding matrix F BB ,in

[0012] Where L is the number of radio frequency links; Used to extract the real part of a matrix; (·) H To obtain the sign of the conjugate transpose; g RF [i] represents the optimal solution to the SOCP problem constructed from the i-th column vector g[i] of the eigenvector group G; argmax(·) is the parameter that maximizes the function; γ is the regularization parameter; ρ i,j This represents the duty cycle of the single-pole double-throw RF switch corresponding to the j-th RF link for the i-th antenna; ||·||2 is the 2-norm symbol; (·) T is the transpose symbol; min(·) is the minimum value symbol of the vector; max(·) is the maximum value symbol of the vector; Δ is the subcarrier spacing; k is the kth information transmission subchannel; K is the number of information transmission subchannels; h[kΔ] is the frequency response of the kΔth subchannel.

[0013] Based on the above method embodiments, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this invention is characterized in that the OFDM system uses K sub-channels with a subcarrier spacing of Δ as information transmission channels. Simultaneously, for the k-th transmission sub-channel ∈ [0, K-1], the system utilizes the current sub-channel and its adjacent left and right sub-channels... Each idle subchannel generates an active interference cancellation signal to cancel harmonic interference.

[0014] Based on the above method embodiments, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this embodiment of the invention, wherein the pulse start time adjustment of the single-pole double-throw RF switch considers that the interference with the greatest impact on the information transmission sub-channel is caused by the harmonic components of the adjacent left and right transmission sub-channels, and reduces such interference by adjusting the pulse start time τ, includes:

[0015] Step 1, according to Calculate the initial precoding matrix of the qth harmonic when τ = 0.

[0016] Step 2: Calculate the coefficient matrix A of harmonic interference caused by the harmonic components of the adjacent left and right transmission sub-channels;

[0017] Step 3: Define vector v = vec(exp(jπΔ(τ / T0))), construct the optimization problem min||A·v||2, and solve vector v using the block coordinate descent method;

[0018] Step 4: Update the starting time matrix τ based on vector v;

[0019] Step 5: Correct the q-th harmonic precoding matrix Each element of the matrix is ​​defined as:

[0020]

[0021] Where vec(·) is the matrix straightening operation; exp(·) is the natural exponential function; τ is the start time matrix of the single-pole double-throw RF switch group, where τ i,j T0 is the pulse start time of the i-th antenna corresponding to the j-th link; T0 is the OFDM symbol duration; sinc(·) is the symbol for the singer function.

[0022] Based on the above method embodiments, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this invention is characterized in that the generation of the active interference cancellation signal includes:

[0023] Step 1, based on the information s sent by the system and The harmonic interference in the transmit subchannel of the calculation system is I = [I[0], I[1], ..., I[K-1]]. T ,in,

[0024]

[0025] Step 2: Introduce active interference cancellation signal Constructing an interference cancellation signal optimization problem:

[0026]

[0027] The interference cancellation signal C is solved using convex optimization tools, including:

[0028]

[0029] Where I[k] is the sum of all harmonic interferences received by the k-th transmitting sub-channel; P c P represents the total power of the interference cancellation signal; μ represents the weighting of the total power of the interference cancellation signal; P TX Ψ represents the total power of the transmitted signal. k Let m be the set of interference cancellation signals whose harmonic components affect the k-th information transmission sub-channel. Specifically, the m-th harmonic component of the n-th interference cancellation signal affects the k-th information transmission sub-channel, where m = kΔ-n and... |·| represents the absolute value sign; Φ k Let N be the set of transmitted sub-channel signals whose harmonic components interfere with the k-th information transmitting sub-channel, that is, the q-th harmonic component of the p-th transmitted sub-channel signal interferes with the k-th information transmitting sub-channel; c Total number of subcarriers; ||·|| F The F-norm symbol is used; s[p] is the transmitted signal of the p-th transmitting sub-channel; e[n] is the complex weight of C[n].

[0030] Based on the above method embodiments, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this embodiment of the invention, wherein the interference cancellation signal and the baseband precoding signal are superimposed and then OFDM modulated, includes: performing an inverse fast Fourier transform on the superimposed signal; adding a cyclic prefix to the transformed signal and converting it into a serial signal, which is then converted into an analog signal by digital-to-analog conversion; and using an RF link to convert the analog signal into an RF signal, amplify and filter it, and then transmit it through the time-modulated antenna array.

[0031] Based on the above method embodiments, the hybrid precoding method for a time-modulated antenna array OFDM system provided in this embodiment of the invention, wherein controlling the antenna array to transmit signals through a single-pole double-throw radio frequency switch includes: in a millimeter-wave OFDM system, using a single-pole double-throw switch to control multiple transmit antennas and corresponding multiple radio frequency links.

[0032] Secondly, embodiments of the present invention provide a time-modulated antenna array OFDM transmission system, comprising: a hybrid precoding parameter generator for generating precoding parameters; a baseband precoder for precoding the baseband; an interference cancellation signal generator for generating an interference cancellation signal; an IFFT module for performing an inverse fast Fourier transform on the signal; an insertion CP circuit for reducing inter-symbol interference and inter-carrier interference; a parallel-to-serial conversion circuit for converting parallel data into serial data; a DAC circuit for converting digital signals into analog signals; an RF link for modulating the baseband signal into an RF signal and performing amplification, filtering, and other processing; a time-modulated antenna array for performing analog precoding based on a single-pole double-throw RF switch and transmitting RF signals; and a main controller for loading corresponding programs to implement the time-modulated antenna array OFDM hybrid precoding method as described in any of the foregoing method embodiments.

[0033] Thirdly, embodiments of the present invention provide a hybrid precoding apparatus for a time-modulated antenna array (OFDM) system, comprising: a first main module for generating hybrid precoding parameters based on channel state information, including the pulse duty cycle, start time, and baseband precoding matrix of the single-pole double-throw (SPDC) RF switch of the time-modulated antenna array; a second main module for performing baseband precoding processing on user data using a baseband precoder; a third main module for generating an active interference cancellation signal, which is then superimposed with the baseband precoding signal for OFDM modulation; and a fourth main module for controlling the antenna array to transmit signals via the SPDC RF switch to suppress sideband radiated interference.

[0034] Fourthly, embodiments of the present invention provide an electronic device, comprising:

[0035] At least one processor, at least one memory, and a communication interface; wherein,

[0036] The processor, memory, and communication interface communicate with each other;

[0037] The memory stores program instructions that can be executed by the processor. The processor calls the program instructions to execute the hybrid precoding method of the OFDM system for time-modulated antenna arrays provided by any of the various implementations of the first aspect.

[0038] Fifthly, embodiments of the present invention provide a non-transitory computer-readable storage medium storing computer instructions that cause a computer to execute a hybrid precoding method for a time-modulated antenna array (OFDM) system provided by any of the various implementations of the first aspect.

[0039] The hybrid precoding method and device for a time-modulated antenna array (OFDM) system provided in this invention adjusts the pulse duty cycle of a single-pole double-throw (SPDT) RF switch and designs a hybrid precoding scheme. Regularization is used to achieve an effective trade-off between beamforming gain and avoiding sideband radiation interference. The maximum harmonic interference phase is controlled by adjusting the pulse start time of the SPDT RF switch, so that the system obtains the minimum maximum harmonic interference under statistically significant conditions. By introducing an active interference cancellation signal, other high-order harmonic interference caused by subcarriers is further canceled. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the hybrid precoding method for a time-modulated antenna array OFDM system provided in an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of the hybrid precoding device structure of the OFDM time-modulated antenna array system provided in this embodiment of the invention;

[0043] Figure 3 A schematic diagram of the physical structure of an electronic device provided in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the OFDM (Optical Frequency Division Multiplexing) transmission system structure provided in an embodiment of the present invention.

[0045] Figure 5 This is a schematic diagram illustrating the subcarrier allocation effect in the hybrid precoding method of the OFDM system with time-modulated antenna array provided in this embodiment of the invention.

[0046] Figure 6 This is a schematic diagram illustrating the parameter control effect of a single-pole double-throw radio frequency switch provided in an embodiment of the present invention.

[0047] Figure 7 A simulation comparison diagram of the hybrid precoding method and related technical solutions of the time-modulated antenna array OFDM system provided in the embodiments of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form feasible technical solutions. Such combinations are not constrained by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. If there are step numbers in the following embodiments, they are only set for ease of explanation and do not limit the order between steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0049] This invention provides a hybrid precoding method for a time-modulated antenna array (OFDM) system, see [link to relevant documentation]. Figure 1 The method includes: generating hybrid precoding parameters based on channel state information, including the pulse duty cycle, start time, and baseband precoding matrix of the single-pole double-throw RF switch of the time-modulated antenna array; performing baseband precoding processing on user data through a baseband precoder; generating an active interference cancellation signal, superimposing it with the baseband precoded signal, and then performing OFDM modulation; and controlling the antenna array to transmit signals through the single-pole double-throw RF switch to suppress sideband radiated interference.

[0050] Based on the above method embodiments, as an optional embodiment, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this invention includes generating hybrid precoding parameters based on channel state information, comprising:

[0051] Step 1: Construct the transmission sub-channel frequency response matrix T based on the channel frequency response matrix H, and then... And extract the eigenvector group G corresponding to its first L largest eigenvalues;

[0052] Step 2: Solve the SOCP optimization problem for all column vectors g[i], i∈[0,L-1] of the feature vector group G:

[0053]

[0054] Step 3, according to g RF The results of [i], i∈[0,L-1] are normalized to obtain the fundamental frequency simulation precoding matrix. And calculate the pulse duty cycle for each single-pole double-throw switch.

[0055]

[0056] Step 4: Based on the fundamental frequency analog precoding matrix Calculate the digital baseband precoding matrix F BB ,in

[0057] In the formula, L represents the number of radio frequency links; Used to extract the real part of a matrix; (·) H To obtain the sign of the conjugate transpose; g RF [i] represents the optimal solution to the SOCP problem constructed from the i-th column vector g[i] of the eigenvector group G; argmax(·) is the parameter that maximizes the function; γ is the regularization parameter; ρ i,j This represents the duty cycle of the single-pole double-throw RF switch corresponding to the j-th RF link for the i-th antenna; ||·||2 is the 2-norm symbol; (·) T is the transpose symbol; min(·) is the minimum value symbol of the vector; max(·) is the maximum value symbol of the vector; Δ is the subcarrier spacing; k is the kth information transmission subchannel; K is the number of information transmission subchannels; h[kΔ] is the frequency response of the kΔth subchannel.

[0058] Specifically, assume the system uses M transmitting antennas and L RF links to transmit wireless signals, and the receiving user uses a single antenna to receive signals. Each RF link is controlled by a single-pole double-throw switch and connected to all transmitting antennas via an adder, where the parameter ρ of the single-pole double-throw switch is... i,j ∈[0,1] and τ i,j ∈[0,T0] respectively control the duty cycle and start time of the single-pole double-throw switch of the j-th RF link corresponding to the i-th transmit antenna. T0 is the time width of the OFDM symbol. The number of OFDM subcarriers in the system is N. c K subcarriers with adjacent number intervals of Δ are used as the information transmission channel. The overall information transmission subcarriers are allocated as follows: Figure 5 As shown. The transmitter hybrid precoding includes a digital baseband precoding matrix.

[0059] F BB =[F BB [0],F BB [1],...,F BB [K-1] and the fundamental frequency analog precoding matrix based on single-pole double-throw switch control The elements in the precoding matrix With single-pole double-throw switch parameter ρ i,j The correspondence is as follows:

[0060]

[0061] To address the harmonic interference caused by TMAA, the precoding matrix for the qth harmonic caused by single-pole double-throw is: The elements of this matrix correspond to each element ρ in the single-pole double-throw switch duty cycle parameter ρ and start time parameter τ. i,j and τ i,j The correspondence is The single-pole double-throw RF switch parameter control demonstration diagram is shown below. Figure 6 As shown.

[0062] The system can use pilot channel estimation to obtain the channel frequency response matrix of all antennas. H = [h[0],h[1],...,h[N] c -1]], then the signal-to-interference-plus-noise ratio of the k-th information transmission channel in [0, K-1] is:

[0063]

[0064] Where Φ k Let σ be the set of transmitted sub-channel signals whose harmonic components interfere with the k-th information transmitting sub-channel, that is, the q-th harmonic component of the p-th transmitted sub-channel signal interferes with the k-th information transmitting sub-channel; 2 Let $\mathbf{a}$ be the Gaussian white noise power of the sub-channel. Set the system transmit power under harmonic interference. The system's total transmit power is P, and it is evenly distributed across each subchannel. The following describes a specific algorithm to maximize the average signal-to-interference-plus-noise ratio (SIR) of each subchannel under the total power constraint:

[0065]

[0066] The fundamental frequency analog precoding matrix and RF switch pulse duty cycle parameters are calculated based on channel state information. The transmit subchannel frequency response matrix is ​​constructed based on the overall channel frequency response matrix H.

[0067]

[0068] And calculate For matrix The eigenvector group corresponding to the first L largest eigenvalues, where Used to extract the real part of a matrix.

[0069] For each column vector g[i] of the obtained matrix G, construct the SOCP optimization problem g RF [i]. A feasible solution is obtained using convex optimization tools, and after normalization, a fundamental frequency simulation precoding matrix is ​​constructed. Simultaneously calculate the corresponding duty cycle parameters of the single-pole double-throw RF switch. Among them ||·|| ∞ The ∞ norm sign is adopted. Subsequently, a precoding matrix based on the fundamental frequency simulation is used. The digital baseband precoding matrix F can be calculated. BB ,in

[0070] Based on the above method embodiments, as an optional embodiment, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this embodiment of the invention, wherein the pulse start time adjustment of the single-pole double-throw RF switch considers that the interference with the greatest impact on the information transmission sub-channel is caused by the harmonic components of the adjacent left and right transmission sub-channels, and reduces such interference by adjusting the pulse start time τ, includes:

[0071] Step 1, according to Calculate the initial precoding matrix of the qth harmonic when τ = 0.

[0072] Step 2: Calculate the coefficient matrix A of harmonic interference caused by the harmonic components of the adjacent left and right transmission sub-channels;

[0073] Step 3: Define vector v = vec(exp(jπΔ(τ / T0))), construct the optimization problem min||A·v||2, and solve vector v using the block coordinate descent method;

[0074] Step 4: Update the starting time matrix τ based on vector v;

[0075] Step 5: Correct the q-th harmonic precoding matrix Each element of the matrix is ​​defined as:

[0076]

[0077] Where vec(·) is the matrix straightening operation; exp(·) is the natural exponential function; τ is the start time matrix of the single-pole double-throw RF switch group, where τ i,j T0 is the pulse start time of the i-th antenna corresponding to the j-th link; T0 is the OFDM symbol duration; sinc(·) is the symbol for the singer function.

[0078] Specifically, the RF switch pulse start time is calculated based on the hybrid precoding matrix to suppress adjacent maximum harmonic interference. The interference with the greatest impact on the information transmission sub-channel is considered to be caused by harmonic components from the adjacent left and right transmission sub-channels. This type of interference is reduced by adjusting the pulse start time τ.

[0079] according to and the corresponding ρ is used to calculate the initial simulation precoding matrix of the qth harmonic when τ = 0. vector

[0080] Construct optimization problem Solve for v, the maximum nearest neighbor harmonic interference matrix for all transmitting sub-channels. When k = 0 When k∈[1,K-2], we have: When k = K-1, we have:

[0081]

[0082] Where conj(·) is used to obtain the complex conjugate of a vector; diag(·) is the function to generate a diagonal matrix. This refers to the Kronecker product operation; K is the number of information transmission sub-channels; k is the k-th information transmission sub-channel; This is the initial harmonic interference matrix assuming τ = 0 for the q-th harmonic interference, where each element of the matrix is ​​given by the formula...

[0083] Calculated.

[0084] This optimization problem is solved using the block coordinate descent method, where each step updates only one element of v. The matrix B = A is constructed. H A. Set a convergence threshold ε, initialize vector v, let the iteration number t = 1, and perform element update calculations for v sequentially. After all elements of v have been updated, calculate the value of ||A·v||2. If it is less than the threshold ε, stop the iteration; if it is greater than the threshold ε, increment the iteration count t by 1 and recalculate the element update of v until the value of ||A·v||2 is less than the threshold ε or the iteration count t reaches a certain value.

[0085] After obtaining the solution to the optimization problem, the inverse transformation of the formula v = vec(exp(jπΔ(τ / T0))) is used to obtain the start time parameter τ of the single-pole double-throw switch and update it.

[0086] Based on the above method embodiments, as an optional embodiment, the hybrid precoding method for a time-modulated antenna array (OFDM) system provided in this invention includes generating an active interference cancellation signal, comprising:

[0087] Step 1, based on the information s sent by the system and The harmonic interference in the transmit subchannel of the calculation system is I = [I[0], I[1], ..., I[K-1]]. T ,in,

[0088]

[0089] Step 2: Introduce active interference cancellation signal Constructing an interference cancellation signal optimization problem:

[0090]

[0091] The interference cancellation signal C is solved using convex optimization tools, including:

[0092]

[0093] Where I[k] is the sum of all harmonic interferences received by the k-th transmitting sub-channel; P c P represents the total power of the interference cancellation signal; μ represents the weighting of the total power of the interference cancellation signal; P TX Ψ represents the total power of the transmitted signal. k Let m be the set of interference cancellation signals whose harmonic components affect the k-th information transmission sub-channel. Specifically, the m-th harmonic component of the n-th interference cancellation signal affects the k-th information transmission sub-channel, where m = kΔ-n and... |·| represents the absolute value sign; Φ k Let N be the set of transmitted sub-channel signals whose harmonic components interfere with the k-th information transmitting sub-channel, that is, the q-th harmonic component of the p-th transmitted sub-channel signal interferes with the k-th information transmitting sub-channel; c Total number of subcarriers; ||·|| F The F-norm symbol is used; s[p] is the transmitted signal of the p-th transmitting sub-channel; e[n] is the complex weight of C[n].

[0094] Specifically, an active interference cancellation signal is calculated to cancel other higher-order harmonic interference within the current transmitted symbol. An interference cancellation signal is introduced. Further cancellation of higher-order sideband radiation interference. For each transmit subchannel k∈[0,K-1], the system utilizes the interference cancellation signal C[kΔ] of the current subchannel and the adjacent left and right sides... The idle sub-channel signal cancels out the interference signal.

[0095] The harmonic components cancel out the interference.

[0096] Assuming the transmitted OFDM signal is s = [s[0], s[1], ..., s[K-1]], then the interference across all channels is I = [I[0], I[1], ..., I[K-1]]. T Construct an interference cancellation signal optimization problem:

[0097]

[0098] in μ is the weighting factor for the total power of the interference cancellation signal, Ψ k Let m be the set of all sub-channels whose harmonic components interfere with the k-th information transmission sub-channel. Specifically, the m-th harmonic component of the n-th sub-channel interferes with the k-th information transmission sub-channel. Considering that the power of the interference cancellation signal is much smaller than the power of the information transmission sub-channel, and the power of higher harmonics caused by the RF switch is even smaller, the interference of the cancellation signal's harmonics on other transmission sub-channels can be approximated as negligible. That is, the cancellation signal of a certain sub-channel only affects a few adjacent information transmission sub-channels, satisfying m = kΔ - n.

[0099] The specific method for calculating and obtaining a feasible solution for interference cancellation signal and power allocation is as follows:

[0100]

[0101] Constructing a strip matrix Where for any i∈[0,K-1], when hour, All other D[i,j] values ​​are 0. The problem of optimizing the interference cancellation signal is transformed into a QCQP problem with a total power constraint: in e = [e[0],e[1],...,e[N] c -1]] T The problem can be solved by using convex optimization tools to obtain a feasible solution for e, thereby obtaining the interference cancellation signal C.

[0102] Based on the above method embodiments, as an optional embodiment, the hybrid precoding method of the OFDM system for time-modulated antenna array provided in this embodiment of the invention, wherein the OFDM modulation is performed after superimposing the baseband precoded signal, includes: performing an inverse fast Fourier transform on the superimposed signal; adding a cyclic prefix to the transformed digital signal, performing a parallel-to-serial conversion, and then performing a digital-to-analog conversion to an analog signal; converting the serial analog signal into a radio frequency signal through a radio frequency link, amplifying and filtering it, and then transmitting it through the time-modulated antenna array.

[0103] Based on the above method embodiments, as an optional embodiment, the hybrid precoding method for a time-modulated antenna array OFDM system provided in this embodiment of the invention, wherein controlling the antenna array to transmit signals through a single-pole double-throw radio frequency switch includes: in a millimeter-wave OFDM system, using a single-pole double-throw switch to control multiple transmit antennas and corresponding multiple radio frequency links.

[0104] For details, please refer to [link / reference]. Figure 7Experimental results comparing the bit error rate (BER) of this method with other methods under the same system parameters for transmitting OFDM 64QAM symbols are presented. Existing hybrid precoding (WHP) schemes rely solely on adjusting the pulse duty cycle of a single-pole double-throw RF switch for hybrid precoding, resulting in a sharp deterioration in performance under medium-to-high signal-to-noise ratio (SNR) conditions. This is because increased signal power also leads to increased higher-order harmonic power. Although idle subcarrier schemes are used to isolate nearby harmonic components, the influence of higher-order harmonics still causes a sharp deterioration in BER performance. The EWHP (Enhanced-WHP) implemented in this invention, while possessing the advantages of existing schemes, utilizes the pulse start time of the time-modulated antenna array to control the phase of the maximum harmonic interference, maximizing the suppression of adjacent maximum harmonic interference, thus significantly improving BER performance compared to existing schemes. Finally, the EWHP with AIC algorithm implemented in this invention, based on EWHP, incorporates Active Interference Cancellation (AIC) technology, effectively solving the sideband radiation problem of higher-order harmonics using no more than one percent of the transmitted signal energy as the interference cancellation signal, further improving BER performance.

[0105] The hybrid precoding method for the OFDM time-modulated antenna array system provided in this invention adjusts the pulse duty cycle of the single-pole double-throw RF switch and designs a hybrid precoding scheme. It achieves an effective trade-off between beamforming gain and avoiding sideband radiation interference by using regularization processing. It controls the phase of the maximum harmonic interference by adjusting the pulse start time of the single-pole double-throw RF switch, so that the system obtains the minimum maximum harmonic interference under statistically significant conditions. By introducing an active interference cancellation signal, it further cancels other high-order harmonic interference caused by the subcarrier.

[0106] This invention provides a time-modulated antenna array OFDM transmission system, see [link to documentation]. Figure 4 The system includes: a hybrid precoding parameter generator for generating precoding parameters; a baseband precoder for precoding the baseband; an interference cancellation signal generator for generating interference cancellation signals; an IFFT module for performing inverse fast Fourier transform on the signal; an insertion CP circuit for reducing inter-symbol interference and inter-carrier interference; a parallel-to-serial conversion circuit for converting parallel digital signals into serial digital signals; a DAC circuit for converting digital signals into analog signals; an RF link for modulating the baseband signal into an RF signal and performing amplification and filtering; a time-modulated antenna array for performing analog precoding based on a single-pole double-throw RF switch and transmitting RF signals; and a master controller (lower-level device, implicitly disclosed) for loading the corresponding program to implement the hybrid precoding method of the time-modulated antenna array OFDM system as described in any of the foregoing method embodiments.

[0107] Specifically, this invention provides a time-modulated antenna array OFDM transmission system, comprising: a hybrid precoding parameter generator, a baseband precoder, an interference cancellation signal generator, an IFFT module, a parallel-to-serial conversion circuit, an insertion CP circuit, a DAC, an RF link, and a time-modulated antenna array based on a single-pole double-throw RF switch. The system is characterized in that: the base station transmitter uses the obtained channel state information as input to the hybrid precoding parameter generator to generate baseband precoding parameters and the parameter information required by the single-pole double-throw switch group; the transmitter inputs user data to the baseband precoder and the interference cancellation signal generator respectively; the output of the baseband precoder is added to the output of the interference cancellation signal generator and then sequentially connected to the IFFT module, the insertion cyclic prefix circuit, the serial-to-parallel conversion circuit, the DAC, and the RF link; finally, the signal is transmitted through the transmitting antenna array after passing through the single-pole double-throw RF switch assembly.

[0108] The present invention discloses a method for calculating hybrid precoding parameters of a time-modulated antenna array (OFDM) system. The method is characterized by: calculating single-pole double-throw (SPDT) RF switch control parameters and baseband precoding parameters based on the user's channel state information, with the optimization objective of maximizing the signal-to-noise ratio (SNR) of the system's sub-channels. The main difference from existing designs lies in: while controlling the pulse duty cycle parameter of the RF switch to maximize the fundamental beamforming gain, the method also reduces the interference of the maximum harmonic to adjacent sub-channels by controlling the pulse start time of the RF switch. The interference cancellation signal generation method for the time-modulated antenna array (OFDM) system uses an active interference cancellation signal to suppress the sideband radiated interference of the time-modulated antenna array (OFDM) system, making it almost negligible.

[0109] The implementation of the various embodiments of the present invention is based on programmed processing by a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention can be encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a hybrid precoding apparatus for a time-modulated antenna array (OFDM) system. This apparatus is used to execute the hybrid precoding method for the time-modulated antenna array (OFDM) system described in the above method embodiments. See also... Figure 2 The device includes: a first main module for generating hybrid precoding parameters based on channel state information, including the pulse duty cycle, start time, and baseband precoding matrix of the time-modulated antenna array single-pole double-throw RF switch; a second main module for performing baseband precoding processing on user data through a baseband precoder; a third main module for generating an active interference cancellation signal, which is then superimposed with the baseband precoded signal and subjected to OFDM modulation; and a fourth main module for controlling the antenna array to transmit signals through the single-pole double-throw RF switch to suppress sideband radiated interference.

[0110] The hybrid precoding device for the OFDM system of the time-modulated antenna array provided in this embodiment of the invention adopts... Figure 2 Several modules in the system achieve an effective trade-off between beamforming gain and avoiding sideband radiation interference by adjusting the pulse duty cycle of the single-pole double-throw RF switch of the time-modulated antenna array and designing a hybrid precoding scheme. Regularization is used to achieve an effective trade-off between beamforming gain and avoiding sideband radiation interference. The maximum harmonic interference phase is controlled by adjusting the pulse start time of the single-pole double-throw RF switch, so that the system obtains the minimum maximum harmonic interference under statistical conditions. By introducing an active interference cancellation signal, other high-order harmonic interference caused by subcarriers is further canceled.

[0111] It should be noted that the apparatus in the device embodiments provided by the present invention can be used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above device embodiments provided by the present invention. As long as those skilled in the art can improve the apparatus in the above device embodiments by referring to the specific technical solutions in other method embodiments and combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, on the basis of the above device embodiments, under the premise of ensuring the practicality of the technical solutions, so as to obtain corresponding device-type embodiments for implementing the methods in other method-type embodiments.

[0112] The method in this embodiment of the invention is implemented using an electronic device; therefore, it is necessary to introduce the relevant electronic device. For this purpose, this embodiment of the invention provides an electronic device, such as... Figure 3 As shown, the electronic device includes at least one processor, a communications interface, at least one memory, and a communications bus, wherein the at least one processor, the communications interface, and the at least one memory communicate with each other via the communications bus. The at least one processor can invoke logical instructions stored in the at least one memory to execute all or part of the steps of the methods provided in the foregoing method embodiments.

[0113] Furthermore, when the logical instructions in at least one of the aforementioned memories can be implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various method embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0114] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0115] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0116] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Based on this understanding, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or sometimes in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0117] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Any expressions such as "predetermined threshold," "preset threshold," etc., without specifying a particular value, can be determined by those skilled in the art through simple experimentation or appropriate adjustments.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hybrid precoding method for a time-modulated antenna array (OFDM) system, characterized in that, include: Hybrid precoding parameters are generated based on channel state information, including the pulse duty cycle, start time, and baseband precoding matrix of the time-modulated antenna array single-pole double-throw RF switch. User data is pre-coded using a baseband pre-encoder. An active interference cancellation signal is generated, superimposed on the baseband precoded signal, and then OFDM modulated. The antenna array transmits signals by controlling the single-pole double-throw radio frequency switch, suppressing sideband radiation interference; The generation of hybrid precoding parameters based on channel state information includes: Step 1, based on the channel frequency response matrix Construct the frequency response matrix of the transmitting sub-channel According to the matrix And extract its front The eigenvector group corresponding to the largest eigenvalue ; Step 2, for the feature vector group All column vectors Solve the SOCP optimization problem separately: ; Step 3, according to The results were normalized to obtain the base. Wave simulation precoding matrix And calculate the pulse duty cycle for each single-pole double-throw switch. ； Step 4: Based on the fundamental frequency analog precoding matrix Calculate the digital baseband precoding matrix ,in ; in, This represents the number of radio frequency links. Used to extract the real part of a matrix; To obtain the sign of the conjugate transpose; For the feature vector group The column vectors The optimal solution to the constructed SOCP problem; To find the independent variable parameter that makes the function take its maximum value; For regularization parameters; Indicates the first The antenna corresponds to the first The duty cycle of the single-pole double-throw RF switch in the RF link; To take the sign of the 2-norm; To obtain the transpose sign; To determine the sign of the minimum value of the vector; To determine the sign of the maximum value of the vector; Subcarrier spacing; For the first One information transmission sub-channel; The number of information transmission sub-channels. For the first Frequency response of each sub-channel.

2. The hybrid precoding method for a time-modulated antenna array OFDM system according to claim 1, characterized in that, The OFDM system uses a subcarrier spacing of of The first sub-channel serves as the information transmission channel; simultaneously, for the second sub-channel... The system utilizes the current sub-channel and its adjacent left and right sub-channels. Each idle subchannel generates an active interference cancellation signal to cancel harmonic interference.

3. The hybrid precoding method for a time-modulated antenna array OFDM system according to claim 1, characterized in that, The pulse start time adjustment of the single-pole double-throw RF switch takes into account that the interference with the greatest impact on the information transmission sub-channel is caused by the harmonic components of the adjacent left and right transmission sub-channels. This is achieved by adjusting the pulse start time. Adjustments to reduce such interference include: Step 1, according to Calculation assumptions The first time Subharmonic initial precoding matrix ; Step 2: Calculate the coefficient matrix of harmonic interference caused by the harmonic components of the adjacent left and right transmission sub-channels. ; Step 3, Define vectors Construct optimization problem The vector is solved by the block coordinate descent method. ; Step four, based on the vector Update the start time matrix ; Step 5, correct the first Subharmonic precoding matrix Each element of the matrix is ​​defined as: ； in, For matrix straightening operations; It is a natural exponential function; This is the start time matrix of a single-pole double-throw RF switch group, where For the first The antenna corresponds to the first The pulse start time of the link; OFDM symbol duration; This is the symbol for the Singer function.

4. The hybrid precoding method for a time-modulated antenna array OFDM system according to claim 1, characterized in that, The generation of the active interference cancellation signal includes: Step 1: According to the information sent by the system as well as Harmonic interference in the transmission sub-channel of the computing system ,in, ； Step 2: Introduce active interference cancellation signal Construct an interference cancellation signal optimization problem: The interference cancellation signal is solved using convex optimization tools. ,include: ； in, For the first The sum of all harmonic interferences experienced by each transmitting sub-channel; The total power of the interference cancellation signal; Weighting the total power of the interference cancellation signal; This represents the total power of the transmitted signal. Its harmonic components for the first The set of interference cancellation signals that affect the information transmission sub-channel, namely the first... The interference cancellation signal of the first The second harmonic component affects the first The information transmission sub-channels are affected, among which and ; To determine the absolute value sign; Its harmonic components for the first The set of transmitted sub-channel signals where interference exists in the nth information transmitting sub-channel, i.e., the nth The first transmission subchannel signal The second harmonic component affects the first The information transmission sub-channel is subject to interference. This represents the total number of subcarriers. To determine the sign of the F-norm; For the first The transmitted signals of each transmission sub-channel; for The complex weights.

5. The hybrid precoding method for a time-modulated antenna array OFDM system according to claim 1, characterized in that, The interference cancellation signal is superimposed with the baseband precoded signal and then OFDM modulated, including: performing an inverse fast Fourier transform on the superimposed signal; adding a cyclic prefix to the transformed signal and converting it into a serial signal, which is then converted into an analog signal by digital-to-analog conversion; and using an RF link to convert the analog signal into an RF signal, amplify and filter it, and then transmit it through a time-modulated antenna array.

6. The hybrid precoding method for a time-modulated antenna array OFDM system according to claim 1, characterized in that, The method of controlling the transmission signal of the time modulation antenna array by a single-pole double-throw radio frequency switch includes: in a millimeter-wave OFDM system, using a single-pole double-throw switch to control multiple transmitting antennas and corresponding multiple radio frequency links.

7. A time-modulated antenna array OFDM hybrid precoding system applying the hybrid precoding method according to any one of claims 1-6, characterized in that, include: A hybrid precoding parameter generator is used to generate precoding parameters; Baseband pre-encoder, used for pre-coding baseband; Interference cancellation signal generator, used to generate interference cancellation signals; The IFFT module is used to perform inverse fast Fourier transform on signals; Insert a CP circuit to reduce inter-symbol interference and inter-carrier interference; a parallel-to-serial conversion circuit to convert parallel data into serial data; a DAC circuit to convert digital signals into analog signals; and an RF link to modulate baseband signals into RF signals and perform amplification and filtering. A time-modulated antenna array for analog precoding and transmitting radio frequency signals based on a single-pole double-throw radio frequency switch; a main controller for loading the corresponding program to implement the hybrid precoding method of the time-modulated antenna array OFDM system as described in any one of claims 1 to 6.

8. A hybrid precoding apparatus for a time-modulated antenna array OFDM system applying the hybrid precoding method according to any one of claims 1-6, characterized in that, include: The first main module is used to generate hybrid precoding parameters based on channel state information, including the pulse duty cycle, start time and baseband precoding matrix of the time-modulated antenna array single-pole double-throw RF switch. The second main module is used to perform baseband precoding processing on user data through a baseband precoder. The third main module is used to generate an active interference cancellation signal, which is then superimposed on the baseband precoded signal and subjected to OFDM modulation. The fourth main module is used to control the antenna array to transmit signals through a single-pole double-throw RF switch, thereby suppressing sideband radiation interference.

9. An electronic device, characterized in that, include: At least one processor, at least one memory, and a communication interface; wherein, The processor, memory, and communication interface communicate with each other; The memory stores program instructions that can be executed by the processor, which invokes the program instructions to perform the method described in any one of claims 1-6.

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