A fast search method of partial transmission sequence algorithm optimal time domain candidate signal

Abstract

The present application is suitable for wideband digital communication technology field, and relates to a fast search method of optimal time domain candidate signal of partial transmission sequence algorithm, a small proportion of time domain candidate signals are calculated first, and a peak threshold C is generated based on the small proportion of time domain candidate signals, then in the calculation process of the remaining time domain candidate signals, the small proportion of local element values of the signals are calculated and compared with the threshold to make a decision, and whether the values of the remaining elements need to be calculated is determined according to the decision. In the case of obtaining the same peak-to-average power ratio performance as the exhaustive search scheme, the high proportion of time domain candidate signals are removed after the values of the small proportion of elements are calculated, and the values of the remaining elements do not need to be calculated, so that the calculation amount of the search process of the optimal time domain candidate signal is greatly reduced, and the peak-to-average power ratio efficiency is provided.

Description

Technical Field

[0001] The invention belongs to the technical field of broadband digital communications, and in particular relates to a fast search method for a partial transmission sequence algorithm. Background Art

[0002] Orthogonal Frequency Division Multiplexing (OFDM) technology enables high-speed data transmission with high spectrum utilization, effectively combats multipath fading, and requires low computational complexity for channel equalization. Therefore, it is widely used in digital broadband communications, including LTE, 5G, digital audio broadcasting (DAB), digital video broadcasting (DVB), and broadband power line carrier (HPLC). However, the high Peak-to-Average Power Ratio (PAPR) of the transmitted signal caused by its multi-carrier system reduces the efficiency of the power amplifier at the transmitter, places higher demands on the linear range of the amplifier, and increases the hardware cost of the system. Therefore, peak-to-average power ratio reduction technology has always been a key technology in OFDM systems.

[0003] Researchers have conducted extensive research on the PAPR reduction problem of OFDM signals and proposed a series of solutions. These solutions can be divided into signal distortion methods and signal distortion-free methods. Signal distortion methods include limiting methods, compression and expansion methods, etc.; signal distortion-free methods can be divided into block coding methods, selective mapping, partial transmit sequences (PTS), etc. Among them, the PTS method is a commonly used peak-to-average ratio reduction algorithm. Its basic idea is to divide an input frame of OFDM symbols into V non-overlapping subsequences in the frequency domain, and multiply each subsequence by a different weighting coefficient. By selecting appropriate weighting coefficients, the PAPR value of the combined sequence is reduced. The core of this method is to generate a certain number of time domain candidate signals, and then select the signal with the smallest PAPR value for transmission. However, when there are W possible weighting coefficients, the process of selecting the optimal signal requires W steps. VThe high computational complexity of multiple iterations places a heavy burden on the system, so both computational complexity and peak-to-average ratio performance must be considered. Currently proposed methods all sacrifice significant PAPR reduction performance to reduce system computational complexity, making them suboptimal. Patent publication number CN102075483B provides a method for reducing the peak-to-average ratio (PAPR) of OFDM signals. The method first employs an SLM or PTS with a smaller number of packets to preliminarily reduce the signal's PAPR. The PAPR is then reduced to the target value by limiting the time-domain data output by the PTS or SLM by setting a limiting rate. This method still suffers from high computational complexity in reducing the peak-to-average ratio of OFDM signals, making it impossible to quickly find the optimal time-domain candidate signal. The drawbacks of the prior art persist.

[0004] Therefore, how to quickly search for time-domain candidate signals with the smallest or smaller peak-to-average ratio, thereby reducing computational complexity and improving peak-to-average ratio reduction efficiency, is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for quickly searching for the optimal time domain candidate signal of the partial transmission sequence algorithm, so as to solve the problems of high computational complexity and poor peak-to-average power reduction efficiency in the selection process of the optimal signal in the partial transmission sequence algorithm of the existing technology.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for quickly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm, comprising the following steps:

[0008] S10, through V times of IDFT operation with length N, calculate x v =IDFT(X v ),v=0,1,...,V-1;

[0009] S20, calculate the time domain signal x=[x(0), x(1), ..., x(N-1)] corresponding to the original frequency domain signal X, that is,

[0010] S30, for x v ,v=0,1,...,V-1 are multiplied by a complex phase rotation factor with an amplitude of 1 where each phase rotation factor is selected from a discrete set of W elements, θ v,w ∈S v ={0,s v,1 ,...,s v,W-1}, calculated

[0011] S40, make W in step S30 V The time domain candidate signal of length N is represented by the following matrix:

[0012] From the matrix W V Select △ time domain candidate signal column vectors and calculate the values ​​of all elements of the column vectors, and select the signal with the smallest peak-to-average ratio, and set the maximum amplitude of the signal as the threshold C;

[0013] S50, set the remaining uncalculated values ​​W V -△ time domain candidate signals are represented by the following matrix:

[0014] Calculate the first row vector in the matrix W V -△ elements, and determine whether the amplitude of each element is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, it is removed from the matrix in step S40;

[0015] S60, assuming that k(0) column vectors are eliminated in step S50, then the matrix in step S50 is updated to contain V W -△-k(0) column vector matrix Θ0, continue to calculate V of the second row vector in matrix Θ0 W -△-k(0) elements, and determine whether the amplitude of each element in the second row vector is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, the column vector corresponding to the element is removed from the matrix Θ0, and the above steps are repeated until the number of column vectors after the matrix is ​​updated is 0, or the process of removing the last row vector is completed;

[0016] S70, assuming that after the calculation process in step S60 is completed, if the number of column vectors after the matrix update is 0, it means that the signal with the minimum peak-to-average ratio selected from the △ time-domain candidate signals in step S40 is all W V The signal with the smallest peak-to-average ratio among the candidate time-domain signals.

[0017] Furthermore, in step S70, if the remaining non-empty matrix after the last row vector is eliminated is Θ N-1 , then from the non-empty matrix Θ N-1 Select a signal with the smallest peak-to-average ratio from all column vector signals of W. V The signal with the smallest peak-to-average ratio among the candidate time-domain signals.

[0018] Furthermore, in step S40, a random function is first used to select theV -1] in W V △ different integers are randomly generated from integers, and the column vectors corresponding to all integers are the corresponding △ candidate signals.

[0019] Furthermore, the specific value of △ in step S40 is 1 / 16 of the total number of time domain candidate signals, that is, , where the symbol Indicates rounding.

[0020] Furthermore, in step S40, it is assumed that W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain is The maximum amplitude of the signal with the smallest peak-to-average ratio selected from the calculated △ time domain candidate signals is C, then

[0021] Furthermore, in step S50, it is assumed that W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain is recorded as The maximum amplitude of the signal with the smallest peak-to-average ratio selected from the calculated △ time domain candidate signals is C, then for the remaining W V Any one of the candidate time domain signals H m ,0≤m≤W V -1, if there is at least one element that satisfies |h n,m |≥C,0≤n≤N-1, then

[0022] Furthermore, for the remaining W V Any one of the candidate time domain signals H m ,0≤m≤W V -1, if an element value h is obtained during the step-by-step calculation of N elements n,m ,0≤n≤N-1, and satisfy|h m,n |≥C, then it is possible to determine the value of the remaining elements without calculating the value of the remaining elements. So the vector H m Remove from search.

[0023] Compared with the prior art, the method for quickly searching for the optimal time-domain candidate signal of the partial transmission sequence algorithm provided by the present invention has at least the following beneficial effects:

[0024] In the prior art, the selection process of the optimal signal of some transmission sequence algorithms requires many iterations, with high computational complexity and poor peak-to-average ratio performance, which puts a heavy burden on the system. The proposed solutions all reduce the amount of system calculation by sacrificing a lot of peak-to-average ratio performance, and cannot take both into account. The present invention first calculates a small proportion of time domain candidate signals, and generates a peak threshold C based on the small proportion of time domain candidate signals. Then, in the calculation process of the remaining time domain candidate signals, a judgment is made by calculating the values ​​of the local elements of the signal in a small proportion and comparing them with the threshold, and based on this, it is determined whether it is necessary to continue calculating the values ​​of the remaining elements. When the same peak-to-average ratio performance as the exhaustive search scheme is achieved, the time domain candidate signals with a higher proportion only need to calculate the values ​​of their small proportion elements before being eliminated, without the need to calculate the values ​​of their remaining elements, thereby greatly reducing the amount of calculation in the search process for the optimal time domain candidate signal and improving peak-to-average ratio efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the scheme of the present invention, a brief introduction is given below to the figures required for use in the description of the embodiments. Obviously, the figures described below are some embodiments of the present invention. For ordinary technicians in this field, other figures can be obtained based on these figures without paying any creative work.

[0026] Figure 1 A schematic diagram of the overall flow of a method for rapidly searching for optimal time-domain candidate signals using a partial transmission sequence algorithm provided by an embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the signal processing flow of the traditional PTS solution;

[0028] Figure 3 A numerical calculation ratio ranking diagram of 65536 time domain candidate signals in a method for quickly searching for the optimal time domain candidate signal of a partial transmission sequence algorithm provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] The present invention provides a method for quickly searching for an optimal time-domain candidate signal for a partial transmission sequence algorithm, which is applied to a PTS peak-to-average ratio reduction technology for OFDM signals. The method comprises:

[0032] S10, through V times of IDFT operation with length N, calculate x v =IDFT(X v ),v=0,1,...,V-1;

[0033] S20, calculate the time domain signal x=[x(0), x(1), ..., x(N-1)] corresponding to the original frequency domain signal X, that is,

[0034] S30, for x v ,v=0,1,...,V-1 are multiplied by a complex phase rotation factor with an amplitude of 1 where each phase rotation factor is selected from a discrete set of W elements, θ v,w ∈S v ={0,s v,1 ,...,s v,W-1}, calculated

[0035] S40, make W in step S30 V The time domain candidate signal of length N is represented by the following matrix:

[0036] From the matrix W V Select △ time domain candidate signal column vectors and calculate the values ​​of all elements of the column vectors, and select the signal with the smallest peak-to-average ratio. Set the maximum amplitude of the signal as the threshold C;

[0037] S50, set the remaining uncalculated values ​​W V -△ time domain candidate signals are represented by the following matrix:

[0038] Calculate the first row vector in the matrix W V -△ elements, and determine whether the amplitude of each element is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, it is removed from the matrix in step S40;

[0039] S60, assuming that k(0) column vectors are eliminated in step S50, then the matrix in step S50 is updated to contain V W -△-k(0) column vector matrix Θ0, continue to calculate V of the second row vector in matrix Θ0W -△-k(0) elements, and determine whether the amplitude of each element in the second row vector is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, the column vector corresponding to the element is removed from the matrix Θ0. Repeat the above steps until the number of column vectors after the matrix update is 0, or the last row vector is removed.

[0040] S70, suppose that after completing the calculation process in step S60, if the number of column vectors after the matrix update is 0, it means that the signal with the minimum peak-to-average ratio selected from the △ time-domain candidate signals in step S40 is all W V The signal with the smallest peak-to-average ratio among the candidate time-domain signals.

[0041] The present invention first calculates a small proportion of time-domain candidate signals and generates a peak threshold C based on this small proportion of time-domain candidate signals. Then, during the calculation of the remaining time-domain candidate signals, a decision is made by comparing the values ​​of the small proportion of local elements of the signal with the threshold, and based on this, a judgment is made as to whether the values ​​of the remaining elements need to be further calculated. While achieving the same peak-to-average power reduction performance as an exhaustive search scheme, time-domain candidate signals with a higher proportion only need to calculate the values ​​of their small proportion of elements before being eliminated, without having to calculate the values ​​of their remaining elements. This significantly reduces the computational complexity of the search process for the optimal time-domain candidate signal and improves peak-to-average power reduction efficiency.

[0042] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0043] In an OFDM system with N subcarriers, X = [X(0), X(1), ..., X(N-1)] represents the frequency domain signal, and x = [x(0), x(1), ..., x(N-1)] represents the corresponding time domain signal. The relationship between the two is as follows:

[0044]

[0045] The peak-to-average ratio of the signal is defined as

[0046]

[0047] where max(|x| 2 ) represents the square of the maximum amplitude of the elements in the signal x, E(|x| 2 ) represents the average power of signal x.

[0048] Among various peak-to-average ratio (PAR) reduction technologies, the PTS algorithm does not cause signal distortion and offers exceptional PARP reduction performance. The core concept of this algorithm is to group N subcarriers, multiply each group of subcarriers by the same phase rotation factor, and then combine them. By selecting the rotation phase for each group, the PARP of the transmitted signal is reduced.

[0049] like Figure 2 As shown, the original frequency domain signal X = [X(0), X(1), ..., X(N-1)] is divided into V non-overlapping group signals, denoted as {X0, X1, ..., X V-1} and these group signals satisfy

[0050]

[0051] Then, a phase rotation factor with an amplitude of 1 is added to each packet signal. where each phase rotation factor is selected from a discrete set of W elements, θ v,w ∈S v ={0,s v,1 ,...,s v,W-1}.

[0052] Note: Each phase rotation factor set of W elements must contain a 0-valued element, which is used to generate the time domain signal corresponding to the original frequency domain signal.

[0053] Then calculate the generated time domain candidate signal set

[0054]

[0055] The above produces a total of W V time domain candidate signals, and then select the signal with the smallest peak-to-average ratio through a certain selection algorithm To send, find the corresponding rotation phase factor, as follows:

[0056]

[0057] Based on the above process, it can be seen that if an exhaustive search scheme is adopted, the sender needs to calculate all W V The value of the time domain candidate signal, the calculation process includes:

[0058] V times of IDFT operation with length N, that is, x is calculated v =IDFT(X v ),v=0,1,...,V-1;

[0059] Then for x v,v=0,1,...,V-1 are multiplied by a complex rotation phase factor with an amplitude of 1, that is, e is calculated jθ x v ,v=0,1,...,V-1 (Note: the first phase factor is 1 and does not need to be calculated);

[0060] Finally, these V complex signals of length N are added together to obtain a time domain candidate signal.

[0061] The IDFT operation process can use the Fast Fourier Transform (IFFT) algorithm, and completing an N-point IFFT operation requires Complex multiplication and Complex number addition. In summary, calculate all W V The number of complex multiplications required for the time-domain candidate signal is , and the number of complex additions is It can be seen that as the values ​​of V and W increase, the amount of algorithm calculation will increase rapidly, especially the number of complex additions will increase exponentially, so it is necessary to carry out research on fast calculation algorithms.

[0062] Based on the above analysis, the present invention provides a fast search method for the optimal time domain candidate signal of the partial transmission sequence algorithm, which is applied to the PTS peak-to-average ratio reduction technology of OFDM signals. Figures 1 to 3 In this embodiment, the method for quickly searching for the optimal time-domain candidate signal of the partial transmission sequence algorithm includes the following steps:

[0063] S10, through V times of IDFT operation with length N, calculate x v =IDFT(X v ),v=0,1,...,V-1;

[0064] S20, calculate the time domain signal x=[x(0), x(1), ..., x(N-1)] corresponding to the original frequency domain signal X, that is,

[0065] S30, for x v ,v=0,1,...,V-1 are multiplied by a complex phase rotation factor with an amplitude of 1 where each phase rotation factor is selected from a discrete set of W elements, θ v,w ∈S v ={0,s v,1 ,...,s v,W-1}, calculated

[0066] S40, without loss of generality, let W in step S30 VThe time domain candidate signal of length N is represented by the following matrix:

[0067] Based on the above analysis, we first start from the matrix W in step S40. V First, select △ time domain candidate signals (column vectors) from the time domain candidate signals and calculate the values ​​of all their elements. Then, select the signal with the smallest peak-to-average ratio from these signals, and set the maximum amplitude of this signal to be C. The specific value of △ is recommended to be about 1 / 16 of the total number of time domain candidate signals, that is, , where the symbol Indicates rounding up.

[0068] Based on the above analysis, we can draw the following conclusions:

[0069] Let W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain is recorded as The maximum amplitude of the signal with the smallest peak-to-average ratio selected from the previously calculated △ time domain candidate signals is C, then

[0070] Let W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain is recorded as The maximum amplitude of the signal with the smallest peak-to-average ratio selected from the △ time-domain candidate signals calculated first is C, then for the remaining W V Any one of the candidate time domain signals H m ,0≤m≤W V -1, if there is at least one element that satisfies |h n,m |≥C,0≤n≤N-1, then

[0071] Since the calculation of all element values ​​of △ time domain candidate signals has been completed in step S40, and the signal with the minimum peak-to-average ratio of C has been selected, the remaining W V -△ time domain candidate signals, its search goal will be equivalently converted to selecting the signal with the smallest peak-to-average ratio from these signals, and the maximum amplitude of the signal needs to be less than C. Therefore, for the remaining W V Any one of the candidate signals H m ,0≤m≤W V -1, if its numerical value is calculated one by one in time sequence, then based on the above conclusion, if an element value h is obtained in the step-by-step calculation process of N elements n,m ,0≤n≤N-1, and satisfy|h m,n |≥C, then it is obvious that without calculating the value of the remaining elements, we can determine So we can transform the vector H m Remove from search.

[0072] S50, set the remaining uncalculated values ​​W V -△ time domain candidate signals are represented by the following matrix:

[0073] Calculate the first row vector in the matrix W V -△ elements, and then determine whether the amplitude of each element is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, it means that the peak-to-average ratio of the column vector corresponding to the element is definitely greater than or equal to the threshold C. Therefore, there is no need to calculate the values ​​of the remaining elements of the vector and they are directly removed from the matrix in step S40.

[0074] S60, assuming that k(0) column vectors are eliminated in step S50, then the matrix in step S50 is updated to contain V W -△-k(0) column vector matrix Θ0, continue to calculate V of the second row vector in matrix Θ0 W -△-k(0) elements, similar to step S50, and then determine whether the amplitude of each element in the second row vector is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, the column vector corresponding to the element is removed from the matrix Θ0. Assuming that k(1) column vectors are removed in this step, the matrix Θ0 is updated to contain V W - A matrix Θ1 with △-k(0)-k(1) column vectors, starting from the third row, repeat the above steps until the number of column vectors after the matrix update is 0, or the last row vector is eliminated;

[0075] S70, suppose that after completing the calculation process in step S60, if the number of column vectors after the matrix update is 0, it means that the signal with the minimum peak-to-average ratio selected from the △ time-domain candidate signals in step S40 is all W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain If the remaining non-empty matrix after the last row vector is eliminated is recorded as Θ N-1 , then select a signal with the smallest peak-to-average ratio from all column vector signals of the matrix, and this signal is the total W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain

[0076] Furthermore, in this embodiment, the strategy for selecting the specific value of the parameter △ in step S40 is as follows:

[0077] A comprehensive analysis of the entire algorithm shows that when the parameter △ is larger, the probability that the corresponding threshold C is smaller is greater, which will be beneficial to quickly eliminate a higher proportion of column vectors in the subsequent screening process of steps S50 to S70, thereby reducing the computational complexity of these steps. However, the increase in parameter △ will increase the computational complexity of the calculation process of step S40, so a certain balancing strategy is required. After a large number of simulation tests, the value of this parameter is set to 1 / 16 of the total number of candidate signals, which is a relatively ideal value.

[0078] Comprehensive analysis of the search process of the embodiment of the present invention shows that the fast search method provided by the embodiment of the present invention is the same as the traditional exhaustive search solution, and can accurately find W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain Therefore, the peak-to-average ratio reduction performance of the fast search method provided by the embodiment of the present invention will be consistent with that of the exhaustive search solution, and will not cause any peak-to-average ratio performance loss.

[0079] Furthermore, in this embodiment, in terms of reducing the complexity of the algorithm, the fast search method of the embodiment of the present invention can compare the threshold value and, when only a small proportion of the element values ​​are calculated, the high proportion of non-signal The time domain candidate signal is directly eliminated without calculating the remaining element values, which effectively reduces the amount of calculation. The following are specific simulation results to illustrate the effect of reducing the amount of calculation in this paper. Assume that an OFDM system uses 16QAM modulation, N = 1024, V = 8, and the rotation phase set satisfies S0 = S1 = ... = S V-1 ={0,π / 2,π,3π / 2}, then one produces 4 8 =65536 candidate time domain signals. For one of the OFDM signals, the threshold C corresponding to the randomly selected △ = 4096 candidate signals is 2.3858. Figure 3 The numerical ratios of the elements that need to be calculated for each of the 65536 candidate time domain signals are given (sorted from large to small). Figure 3 As can be seen from the results, a large proportion of candidate signals are eliminated after a small proportion of element numerical calculations are performed. The remaining element numerical calculations for a large proportion of the candidate signals no longer need to be performed. In addition to the original △ = 4096 candidate signals, there are still 960 candidate time-domain signals remaining in step S70 that require all element numerical calculations. The final statistical results show that the number of elements in the matrix of step S40 calculated from step S40 to step S70 is 15197824, accounting for 1024 × 65536 = 67108864 of the total number of elements, or approximately 22.65%. Therefore, it can be seen that the fast search method of the embodiment of the present invention can effectively reduce the computational complexity of the search algorithm and improve the efficiency of peak-to-average reduction.

[0080] The fast search method for the optimal time-domain candidate signal of the partial transmission sequence algorithm described in the above embodiment is compared with the prior art. The selection process of the optimal signal of the partial transmission sequence algorithm in the prior art requires many iterations, has high computational complexity, and poor peak-to-average ratio performance, which puts a heavy burden on the system. The proposed solutions also reduce the amount of system calculation by sacrificing a lot of peak-to-average ratio performance, and cannot take both into account. The present invention first calculates a small proportion of time-domain candidate signals and generates a peak threshold C based on the small proportion of time-domain candidate signals. Then, in the calculation process of the remaining time-domain candidate signals, a judgment is made by calculating the values ​​of the local elements of the small proportion of the signal and comparing them with the threshold, and based on this, it is determined whether it is necessary to continue calculating the values ​​of the remaining elements. When the peak-to-average ratio performance is achieved that is the same as that of the exhaustive search scheme, the time-domain candidate signals with a higher proportion only need to calculate the values ​​of their small proportion of elements before being eliminated, without calculating the values ​​of their remaining elements, thereby significantly reducing the computational complexity of the search process for the optimal time-domain candidate signal and improving peak-to-average ratio efficiency.

[0081] Obviously, the embodiments described above are only preferred embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned specific embodiments, or to make equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the present invention specification and drawings, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A fast search method for optimal time domain candidate signals of a partial transmission sequence algorithm, characterized in that: The following steps are involved: S10, through V times of IDFT operation with length N, calculate x v =IDFT(X v ),v=0,1,...,V-1; S20, calculate the time domain signal x=[x(0), x(1), ..., x(N-1)] corresponding to the original frequency domain signal X, that is, S30, for x v ,v=0,1,...,V-1 are multiplied by a complex phase rotation factor with an amplitude of 1 v=0,1,...,V-1,w=0,1,...,W-1, where each phase rotation factor is selected from a discrete set of W elements, i.e., θ v,w ∈S v ={0,s v,1 ,...,s v,W-1 }, calculated v=0,1,...,V-1,w=0,1,...,W-1; S40, make W in step S30 V The time domain candidate signal of length N is represented by the following matrix: From this matrix W V Select △ time domain candidate signal column vectors and calculate the values ​​of all elements of the column vectors, and select the signal with the smallest peak-to-average ratio, and set the maximum amplitude of the signal as the threshold C; S50, set the remaining uncalculated values ​​W V -△ time domain candidate signals are represented by the following matrix: Calculate the first row vector in the matrix W V -△ elements, and determine whether the amplitude of each element is greater than or equal to the threshold C. If the amplitude of an element is greater than or equal to the threshold C, it is removed from the matrix in step S40; S60: Assume that k(0) column vectors are eliminated in step S50, then the matrix in step S50 is updated to contain W V -△-k(0) column vector matrix Θ0, continue to calculate W of the second row vector in matrix Θ0 V -△-k(0) elements, and determining whether the amplitude of each element in the second row vector is greater than or equal to the threshold C one by one. If the amplitude of an element is greater than or equal to the threshold C, the column vector corresponding to the element is removed from the matrix Θ0, and S60 is repeated until the number of column vectors after the matrix is ​​updated is 0, or the process of removing the last row vector is completed; S70, assuming that after the calculation process in step S60 is completed, if the number of column vectors after the matrix update is 0, it means that the signal with the minimum peak-to-average ratio selected from the △ time-domain candidate signals in step S40 is all W V The signal with the smallest peak-to-average ratio among the candidate time-domain signals.

2. The method for rapidly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm according to claim 1, characterized in that: In step S70, if the remaining non-empty matrix after the last row vector is eliminated is Θ N-1 , then from the non-empty matrix Θ N-1 Select a signal with the smallest peak-to-average ratio from all column vector signals of W. V The signal with the smallest peak-to-average ratio among the candidate time-domain signals.

3. The method for rapidly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm according to claim 1, characterized in that: In the step S40, a random function is first used to select the V -1] in W V △ different integers are randomly generated from integers, and the column vectors corresponding to all integers are the corresponding △ candidate signals.

4. The method for rapidly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm according to claim 3, characterized in that: The specific value of △ in step S40 is 1 / 16 of the total number of candidate time domain signals, that is, , where the symbol Indicates rounding.

5. The method for rapidly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm according to claim 1, characterized in that: In the step S40, it is assumed that W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain is The maximum amplitude of the signal with the smallest peak-to-average ratio selected from the calculated △ time domain candidate signals is C, then 6. The method for rapidly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm according to claim 5, characterized in that: In the step S50, it is assumed that W V The signal with the minimum peak-to-average ratio among the candidate signals in the time domain is recorded as The maximum amplitude of the signal with the smallest peak-to-average ratio selected from the calculated △ time domain candidate signals is C, then for the remaining W V Any one of the candidate time domain signals H m ,0≤m≤W V -1, if there is at least one element that satisfies |h n,m |≥C,0≤n≤N-1, then 7. The method for rapidly searching for optimal time-domain candidate signals of a partial transmission sequence algorithm according to claim 5, characterized in that: For the remaining W V Any one of the candidate time domain signals H m ,0≤m≤W V -1, if an element value h is obtained during the step-by-step calculation of N elements n,m ,0≤n≤N-1, and satisfy|h m,n |≥C, then it is possible to determine the value of the remaining elements without calculating the value of the remaining elements. So the vector H m Remove from search.

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