Signal capture and synchronization method, receiver and medium

Abstract

The present application discloses a signal capture and synchronization method and a receiver, which relates to the field of wireless communication. The method includes: constructing a segmented training sequence; inserting the segmented training sequence between payload data blocks with cyclic prefixes to form a transmission data frame; and synchronously capturing a received signal obtained by transmitting the transmission data frame through a channel. By dividing the training sequence into several segments of segmented training sequences and inserting them between payload data blocks with cyclic prefixes to form a transmission data frame for transmission, it is ensured that the synchronization training sequence will not be completely in a time window with severe fading. Under the premise of not increasing the channel overhead, effective capture and synchronization of the transmission signal of the fading channel can be achieved at an extremely low signal-to-noise ratio.

Description

Technical Field

[0001] The present application relates to the field of wireless communications, and in particular to a signal capture and synchronization method, a receiver and a medium. Background Art

[0002] In wireless communication systems, signal transmission is often affected by multiple interference factors such as receiver noise, transmission channel environment noise, and human interference, resulting in signal quality degradation. Due to the constraints of transmitter power, channel conditions, communication distance and other conditions, some communications, especially guaranteed communications, need to achieve effective connectivity under extremely low signal-to-noise ratio conditions. However, due to the movement of transmitters, reflectors and receivers, the transmission channel has time-varying fading.

[0003] At present, the traditional signal capture and synchronization method sends the training sequences used for synchronization capture together. In a time-varying fading channel environment, the training sequences fall into the fading time window with a certain probability, resulting in a significant decrease in the signal capture probability and synchronization quality, which is difficult to meet the needs of modern communication systems. Summary of the invention

[0004] The purpose of the present application is to provide a signal capture and synchronization method, a receiver and a medium to solve the problem that the signal capture probability and synchronization quality of the existing signal capture and synchronization methods do not meet the requirements of modern communication systems.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a signal capture and synchronization method, comprising:

[0007] Construct segmented training sequences;

[0008] Inserting the segmented training sequence between the payload data blocks with cyclic prefixes to form a transmission data frame;

[0009] Signal capture and timing are performed on the received signal obtained by transmitting the transmission data frame through the channel.

[0010] Optionally, constructing a segmented training sequence includes:

[0011] Construct J segmented training sequences S according to the following formula j :

[0012] S j ={S j (k)},0≤j≤J-1,0≤k≤K-1;

[0013] Among them, S j (k) represents the jth segment training sequence S jThe kth sample data, K is the segmented training sequence S j Length;

[0014] The step of inserting the segmented training sequence between payload data blocks with cyclic prefixes to form a transmission data frame comprises:

[0015] The J segmented training sequences S j Insert Q payload data blocks D with cyclic prefix q Between, a transmission data frame is formed, in which:

[0016] D q ={D q (p)},0≤q≤Q-1,0≤p≤P-1;

[0017] In the above formula, D q (p) represents the qth payload data block D with a cyclic prefix q The pth sample data, P is the payload data block D with a cyclic prefix q The length of Q is greater than or equal to J-1.

[0018] Optionally, the transmission data frame is:

[0019] X={S0,D0,S1,D1,…,D J-2 ,S J-1 ,D J-1 ,D J ,…,D Q-1};

[0020] Wherein, X is the transmission data frame.

[0021] Optionally, a signal capture and synchronization method based on time diversity is used to perform signal capture and timing on a received signal obtained by transmitting the transmission data frame through a channel;

[0022] The signal capture and synchronization method based on time diversity is used to capture and time the received signal obtained by transmitting the transmission data frame through the channel, including:

[0023] The sample data of the received signal at each time sample point is divided according to the order of the transmission data frame, and the sample data of a single time sample point is divided into J candidate segmented training sequences with an interval of P and a length of K, wherein: K is the length of the segmented training sequence, P is the length of the payload data block with a cyclic prefix, and J is the number of the segmented training sequences;

[0024] Cross-correlate and sum each candidate segment training sequence of the sample data of the received signal at each time sample point with the corresponding local segment training sequence to obtain J segment correlation sum values ​​at each time sample point:

[0025] Performing a fast Fourier transform operation on the J segment correlation sum values ​​at each time sample point, and determining the absolute maximum value of the fast Fourier transform operation value at each time sample point and its corresponding frequency index position;

[0026] A peak curve is constructed by using the absolute maximum value of the fast Fourier transform operation value of each time sample point, wherein the abscissa of the peak curve is the time sample point, and the ordinate is the absolute maximum value of the fast Fourier transform operation value of each time sample point;

[0027] Determine whether the absolute maximum value of the fast Fourier transform operation value of the peak curve is less than a preset threshold; if so, determine that the output state is an uncaptured state; otherwise, determine that the output state is a captured state, and select the time sample point corresponding to the maximum value of the peak curve as the synchronization starting point to complete time synchronization.

[0028] Optionally, the signal capture and synchronization method further includes:

[0029] When determining the absolute maximum value of the fast Fourier transform operation result of each time sample point, the frequency index position corresponding to the absolute maximum value is recorded;

[0030] After the synchronization starting point is obtained, the frequency index position of the synchronization starting point is determined according to the record of the frequency index position corresponding to the maximum absolute value of the fast Fourier transform operation result of each time sample point.

[0031] Optionally, the signal capture and synchronization method further includes:

[0032] After determining the synchronization start point and its frequency index position, the carrier frequency difference between the receiving end and the transmitting end, namely the frequency offset, is estimated, and the estimated frequency offset estimation value is used to perform frequency offset compensation.

[0033] Optionally, the frequency offset is estimated according to the following process:

[0034] Using the obtained synchronization starting point and its frequency index position, the first frequency offset estimation is performed according to the following formula:

[0035]

[0036] Where d is the synchronization starting point, Ind_f(d) is the frequency index position of the synchronization starting point, and f ind (d) is the first frequency offset estimate, f s is the sampling frequency, J is the total number of the segmented training sequences, K is the length of the segmented training sequence, and P is the length of the payload data block with a cyclic prefix;

[0037] Using the cyclic prefix of the payload data block in the constructed transmission data frame and the synchronization start point, the second frequency offset estimation is performed according to the following formula:

[0038]

[0039] Among them, f CP(d) is the second frequency offset estimation value, angle(C(d)) represents the phase angle of the complex number C(d), C(d) is the estimated intermediate value, r(d+(K+P)×q+K+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+g, r * (d+(K+P)×q+K+g) is the conjugate complex number of r(d+(K+P)×q+K+g), r(d+(K+P)×q+K+P-G+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+P-G+g, r(d+K×J+P×q+g) is the sample data of the received signal at the time sample point d+K×J+P×q+g, r * (d+K×J+P×q+g) is the conjugate complex number of r(d+K×J+P×q+g), r(d+K×J+P×q+P-G+g) is the sample data of the received signal at the time sample point d+K×J+P×q+P-G+g, and G is the cyclic prefix length of the payload data block;

[0040] Calculate the intermediate estimate using the following formula

[0041]

[0042] in, represents rounding down, N and M are the integers that satisfy the equation A set of smallest positive integers;

[0043] From all possible combinations of n and m, find the value that makes The smallest {n,m} is recorded as {n',m'}, and the final frequency offset estimate Δf' is:

[0044]

[0045] The final offset estimation value Δf' is used to perform frequency offset compensation at the receiving end and the transmitting end.

[0046] In a second aspect, the present application provides a receiver, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of any one of the signal capture and synchronization methods described above.

[0047] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the signal capture and synchronization methods described above.

[0048] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0049] The present application provides a signal capture and synchronization method, a receiver and a medium. By dividing a training sequence into a plurality of segmented training sequences and inserting them between payload data blocks with cyclic prefixes, a transmission data frame is formed for transmission, thereby ensuring that the synchronization training sequence will not be completely in a time window with severe fading. Without increasing the channel overhead, effective capture and synchronization of the transmission signal of the fading channel can be achieved at an extremely low signal-to-noise ratio, so that the capture frequency and synchronization quality of the signal meet the requirements of modern communication systems, and the problem that the capture probability and synchronization quality of the signal of the existing signal capture and synchronization methods do not meet the requirements of modern communication systems is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A flow chart of a signal acquisition and synchronization method provided in one embodiment of the present application;

[0052] Figure 2 This is a schematic diagram of the structure of a transmission data frame according to an embodiment of the present application;

[0053] Figure 3 for Figure 1 A detailed flow chart of the step of synchronously capturing the received signal obtained by transmitting the transmission data frame through the channel;

[0054] Figure 4 A schematic diagram showing the relationship between the CP and PMF-FFT frequency offset estimation results and the actual frequency offset according to an embodiment of the present application;

[0055] Figure 5 A schematic diagram of functional modules of a signal capture and synchronization device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0058] In an exemplary embodiment, Figure 1 As shown, a signal capture and synchronization method is provided, including the following steps 101 to 103. Among them:

[0059] Step 101: construct a segmented training sequence.

[0060] In the embodiment of the present application, the constructed segmented training sequence should have good autocorrelation so that an obvious correlation peak can be obtained by using a cross-correlation operation in the synchronization capture stage.

[0061] Step 102: insert the segmented training sequence between payload data blocks with cyclic prefixes to form a transmission data frame.

[0062] In the embodiment of the present application, the number of payload data blocks with cyclic prefixes should be greater than or equal to the number of constructed segmented training sequences minus one, ensuring that the segmented training sequences are not set continuously to obtain time diversity benefits. The length of the transmission data frame is greater than the channel coherence time.

[0063] Step 103, performing signal capture and timing on the received signal obtained by transmitting the transmission data frame through the channel.

[0064] In the embodiment of the present application, the receiver completes the signal capture decision and determines the timing sample point by using the transmission data frame formed in step 102.

[0065] By implementing the above steps 101 to 103, by dividing the training sequence into several segmented training sequences and distributing them in a data frame much larger than the channel coherence time for transmission, it is ensured that the synchronization training sequence will not be completely in the time window with severe fading. Without increasing the channel overhead, the effective capture and synchronization of the fading channel transmission signal can be achieved under extremely low signal-to-noise ratio, so that the signal capture frequency and synchronization quality meet the requirements of modern communication systems, and solve the problem that the signal capture probability and synchronization quality of the existing signal capture and synchronization methods do not meet the requirements of modern communication systems. In addition, the signal capture and synchronization method of the embodiment of the present application is suitable for communication systems of wireless fading channels such as shortwave in extremely low signal-to-noise ratio environments.

[0066] As an optional implementation, in step 101, constructing a segmented training sequence includes:

[0067] Construct J segmented training sequences S with the same length of K according to the following formula: j :

[0068] S j ={S j (k)},0≤j≤J-1,0≤k≤K-1;

[0069] Among them, S j (k) represents the jth segment training sequence S j The kth sample data.

[0070] As an optional implementation, in step 102, inserting the segmented training sequence between payload data blocks with cyclic prefixes to form a transmission data frame includes:

[0071] The J segmented training sequences S j Insert Q payload data blocks D with cyclic prefix of length P q Between, a transmission data frame is formed, in which:

[0072] D q ={D q (p)},0≤q≤Q-1,0≤p≤P-1;

[0073] In the above formula, D q (p) represents the qth payload data block D with a cyclic prefix q The pth sample data, Q is greater than or equal to J-1.

[0074] As an optional implementation, J segmented training sequences S j Insert Q payload data blocks D with cyclic prefix of length P uniformly q Between them, a transmission data frame is formed, and Q is greater than or equal to J-1.

[0075] As an optional embodiment, the following composition is used: Figure 2 The transmission data frame shown:

[0076] X={S0,D0,S1,D1,…,D J-2 ,S J-1 ,D J-1 ,D J ,…,D Q-1};

[0077] Among them, X is the transmission data frame, S0 is the first segment training sequence, S1 is the second segment training sequence, SJ-1 is the Jth segment training sequence, D0 is the first payload data block with a cyclic prefix, D1 is the second payload data block with a cyclic prefix, and D J-2 is the J-1th payload data block with a cyclic prefix, D J is the Jth payload data block with a cyclic prefix, D Q-1 It is the Qth payload data block with a cyclic prefix.

[0078] In another exemplary embodiment of the present application, the step 103 uses a signal capture and synchronization method based on time diversity to perform signal capture and timing on the received signal obtained by transmitting the transmission data frame through the channel. Figure 3 As shown, the signal capture and synchronization method based on time diversity is used to capture and time the received signal obtained by transmitting the transmission data frame through the channel, including the following steps 201 to 205. Wherein:

[0079] Step 201, the sample data of the received signal at each time sample point is divided according to the order of the transmission data frame, and the sample data of a single time sample point is divided into J candidate segmented training sequences with an interval of P and a length of K, wherein: K is the length of the segmented training sequence, P is the length of the payload data block with a cyclic prefix, and J is the number of the segmented training sequences.

[0080] In the embodiment of the present application, the sample data r(i) of the received signal at the time sample point i is:

[0081]

[0082] Where V is the number of resolvable paths in the wireless transmission channel, h v (i) is the fading factor of the vth resolvable path, with time index i indicating time-varying, X is the transmission data frame, τ v is the delay of the vth variable path, f s is the sampling frequency, π is the circumference of a circle, j is the imaginary unit, and n0 is the additive white Gaussian noise.

[0083] The sample data r(i) of the received signal at time sample point i is divided according to the structure of the transmission data frame to obtain J candidate segmented training sequences r(i+j*(K+P)+k) with an interval of P and a length of K, j={0,1,…,J-1}, and at each j, k={0,1,…,K-1}.

[0084] Step 202: perform cross-correlation operation on each candidate segment training sequence of the sample data of the received signal at each time sample point and the corresponding local segment training sequence, and then sum them up to obtain J segment correlation sum values ​​at each time sample point.

[0085] In the embodiment of the present application, the data r(i+j*(K+P)+k) of each candidate segment training sequence of the received signal r(i) at each time sample point i and the data S of the corresponding local segment training sequence are calculated according to the following formula: j (k) Perform cross-correlation operation and then sum:

[0086]

[0087] Among them, R j (i) is the jth segment correlation sum value, K is the segment training sequence S j The length of P is the payload data block D with a cyclic prefix. q Length, is the segmented training sequence S j The kth sample data S j The complex conjugate of (k).

[0088] Step 203: Perform a fast Fourier transform operation on the J segment correlation sum values ​​at each time sample point, and determine the absolute maximum value of the J fast Fourier transform operation results at each time sample point.

[0089] In the embodiment of the present application, the J segment correlation sum values ​​are subjected to a fast Fourier transform operation according to the following formula to obtain the maximum absolute value of the J fast Fourier transform operation results:

[0090]

[0091] Among them, Y j (i) is the fast Fourier transform value of the jth segment correlation sum value at time sample point i, fft is the fast Fourier transform operation, M(i) is Y j (i), the absolute maximum value of 0≤j≤J-1.

[0092] Step 204, construct a peak curve using the absolute maximum value of the fast Fourier transform operation value of each time sample point, wherein the abscissa of the peak curve is the time sample point and the ordinate is the absolute maximum value of the fast Fourier transform operation value of each time sample point.

[0093] Step 205, determine whether the absolute maximum value of the fast Fourier transform operation value of the peak curve is less than a preset threshold; if so, output the uncaptured state (indicating that there is no signal, and re-capture is performed after receiving new data); otherwise, output the captured state, and select the sampling position (time sample point) corresponding to the absolute maximum value of the fast Fourier transform operation value of the peak curve as the synchronization starting point (frame starting position) d to complete the time synchronization.

[0094] In another exemplary embodiment of the present application, the signal capture and synchronization method further includes:

[0095] When determining the absolute maximum value M(i) of the fast Fourier transform operation result of each time sample point, the frequency index position Ind_f(i) corresponding to the absolute maximum value is recorded:

[0096]

[0097] Among them, Ind(i) represents the j value corresponding to the maximum value M(i);

[0098] After the synchronization starting point d is obtained, the frequency index position Ind_f(d) of the synchronization starting point d is determined based on the record of the frequency index position Ind_f(i) corresponding to the absolute maximum value of the fast Fourier transform operation result of each time sample point.

[0099] In another exemplary embodiment of the present application, the signal capture and synchronization method further includes:

[0100] After determining the synchronization starting point d and its frequency index position Ind_f(d), the carrier frequency difference between the receiving end and the transmitting end, namely the frequency offset, is estimated, and the estimated frequency offset estimation value is used to perform frequency offset compensation to achieve frequency synchronization.

[0101] As an optional implementation manner, the frequency offset is estimated according to the following process:

[0102] Using the obtained synchronization starting point d and its frequency index position Ind_f(d), the first frequency offset estimation is performed according to the following formula:

[0103]

[0104] Among them, f ind(d) is the first frequency offset estimate, f s is the sampling frequency, J is the total number of segmented training sequences, K is the length of the segmented training sequence, and P is the length of the payload data block with a cyclic prefix;

[0105] Using the cyclic prefix of the payload data block in the constructed transmission data frame and the synchronization starting point d, the second frequency offset estimation is performed according to the following formula:

[0106]

[0107] Among them, f CP(d) is the second frequency offset estimation value, angle(C(d)) represents the phase angle of the complex number C(d), C(d) is the estimated intermediate value, r(d+(K+P)×q+K+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+g, r* (d+(K+P)×q+K+g) is the conjugate complex number of r(d+(K+P)×q+K+g), r(d+(K+P)×q+K+P-G+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+P-G+g, r(d+K×J+P×q+g) is the sample data of the received signal at the time sample point d+K×J+P×q+g, r * (d+K×J+P×q+g) is the conjugate complex number of r(d+K×J+P×q+g), r(d+K×J+P×q+P-G+g) is the sample data of the received signal at the time sample point d+K×J+P×q+P-G+g, and G is the cyclic prefix length of the payload data block;

[0108] In the embodiment of the present application, the first frequency offset estimation value f ind(d) The relationship with the actual frequency deviation Δf is as follows Figure 4 As shown, Figure 4 The PMF-FFT estimation result is f ind(d) , the relational expression is as follows:

[0109]

[0110] Where m is an integer, and δ2 is the error introduced by noise and calculation accuracy during the calculation process;

[0111] The second frequency offset estimate f CP(d) The relationship with the actual frequency deviation is as follows Figure 4 As shown, Figure 4 The CP estimation result is f CP(d) , the relational expression is as follows:

[0112]

[0113] Where n is an integer, δ1 is the error introduced by noise and calculation accuracy during the calculation process;

[0114] The first frequency offset estimate f ind(d) The range is The second frequency offset estimate f CP(d) The range is Both ranges are relatively small. Compared with the traditional PMF-FFT method, since the interval between the starting positions of the segmented training sequence in the embodiment of the present application is increased, the f ind(d) It can be seen that the frequency offset estimation range will be reduced. Based on this, a method for frequency offset estimation using the cyclic prefix of the payload data block is proposed. The first frequency offset estimation value f ind(d) and the second frequency offset estimate f CP(d) Combined with, the frequency estimation range can be extended to That is to say Where N and M satisfy the equation The final frequency offset estimate is determined by the following steps:

[0115] Calculate the intermediate estimate using the following formula

[0116]

[0117] in, Indicates rounding down;

[0118] From all possible combinations of n and m, find the value that makes The smallest {n,m} is recorded as {n',m'}, and the final frequency offset estimate Δf' is:

[0119]

[0120] The final offset estimation value Δf' is used to perform frequency offset compensation at the receiving end and the transmitting end.

[0121] Based on the same inventive concept, the embodiment of the present application also provides a signal capture and synchronization device for implementing the signal capture and synchronization method involved above. The implementation solution provided by the device to solve the problem is similar to the implementation solution recorded in the above method, so the specific limitations in one or more signal capture and synchronization device embodiments provided below can refer to the limitations of the signal capture and synchronization method above, and will not be repeated here.

[0122] In an exemplary embodiment, Figure 5 As shown, a signal capture and synchronization device 30 is provided, comprising:

[0123] A training sequence construction module 301 is used to construct a segmented training sequence;

[0124] A transmission data framing module 302 is used to insert the segmented training sequence between the payload data blocks with cyclic prefixes to form a transmission data frame;

[0125] The signal capture and timing module 303 is used to perform signal capture and timing on the received signal obtained by transmitting the transmission data frame through the channel.

[0126] As an optional implementation manner, the training sequence construction module 301 is further used to:

[0127] Construct J segmented training sequences S with the same length of K according to the following formula: j :

[0128] S j ={S j(k)},0≤j≤J-1,0≤k≤K-1;

[0129] Among them, S j (k) represents the jth segment training sequence S j The kth sample data.

[0130] As an optional implementation manner, the transmission data framing module 302 is further configured to:

[0131] The J segmented training sequences S j Insert Q payload data blocks D with cyclic prefix of length P q Between, a transmission data frame is formed, in which:

[0132] D q ={D q (p)},0≤q≤Q-1,0≤p≤P-1;

[0133] In the above formula, D q (p) represents the qth payload data block D with a cyclic prefix q The pth sample data, Q is greater than or equal to J-1.

[0134] As an optional implementation manner, the transmission data framing module 302 is further configured to:

[0135] The J segmented training sequences S j Insert Q payload data blocks D with cyclic prefix of length P uniformly q Between them, a transmission data frame is formed, and Q is greater than or equal to J-1.

[0136] As an optional implementation manner, the transmission data framing module 302 is further configured to:

[0137] The transmission data frame is composed as follows:

[0138] X={S0,D0,S1,D1,…,D J-2 ,S J-1 ,D J-1 ,D J ,…,D Q-1}.

[0139] Among them, X is the transmission data frame, S0 is the first segment training sequence, S1 is the second segment training sequence, S J-1 is the Jth segment training sequence, D0 is the first payload data block with a cyclic prefix, D1 is the second payload data block with a cyclic prefix, and D J-2 is the J-1th payload data block with a cyclic prefix, D J is the Jth payload data block with a cyclic prefix, DQ-1 It is the Qth payload data block with a cyclic prefix.

[0140] As an optional implementation manner, the signal capture timing module 303 is further used to:

[0141] The sample data of the received signal at each time sample point is divided according to the order of the transmission data frame, and the sample data of a single time sample point is divided into J candidate segmented training sequences with an interval of P and a length of K, wherein: K is the length of the segmented training sequence, P is the length of the payload data block with a cyclic prefix, and J is the number of the segmented training sequences;

[0142] Each candidate segmented training sequence of the sample data of the received signal at each time sample point is cross-correlated with the corresponding local segmented training sequence and then summed to obtain J segmented correlation sum values ​​at each time sample point. For detailed introduction, please refer to the description of the above method embodiment, which will not be repeated here;

[0143] Performing a fast Fourier transform operation on the J segmented correlation sum values ​​at each time sample point, and determining the absolute maximum value of the J fast Fourier transform operation results at each time sample point. For specific related introductions, please refer to the records of the above method embodiment, which will not be repeated here;

[0144] A peak curve is constructed by using the absolute maximum value of the fast Fourier transform operation value of each time sample point, wherein the abscissa of the peak curve is the time sample point and the ordinate is the absolute maximum value of the fast Fourier transform operation value of each time sample point;

[0145] Determine whether the absolute maximum value of the fast Fourier transform operation value of the peak curve is less than a preset threshold; if so, output the uncaptured state; otherwise, output the captured state, and select the sampling position (time sample point) corresponding to the absolute maximum value of the fast Fourier transform operation value of the peak curve as the synchronization starting point (frame starting position) d to complete time synchronization.

[0146] As an optional implementation manner, the signal capture timing module 303 is further used to:

[0147] When determining the absolute maximum value M(i) of the fast Fourier transform operation result of each time sample point, the frequency index position Ind_f(i) corresponding to the absolute maximum value is recorded:

[0148]

[0149] After the synchronization starting point d is obtained, the frequency index position Ind_f(d) of the synchronization starting point d is determined according to the calculation method of Ind_f(i).

[0150] As an optional implementation manner, the signal capture and synchronization device 30 further includes:

[0151] The frequency deviation estimation module 304 is used to estimate the carrier frequency difference between the receiving end and the transmitting end, that is, the frequency deviation, after determining the synchronization starting point d and its frequency index position Ind_f(d);

[0152] The frequency offset compensation module 305 is used to use the estimated frequency offset value to perform frequency offset compensation to achieve frequency synchronization.

[0153] As an optional implementation manner, the frequency offset estimation and compensation module 304 is further configured to:

[0154] Using the obtained synchronization starting point d and its frequency index position Ind_f(d), the first frequency offset estimation is performed according to the following formula:

[0155]

[0156] Among them, f ind(d) is the first frequency offset estimate, f s is the sampling frequency, J is the total number of segmented training sequences, K is the length of the segmented training sequence, and P is the length of the payload data block with a cyclic prefix;

[0157] The second frequency offset estimation is performed using the cyclic prefix of the payload data block in the constructed transmission data frame and the synchronization starting point d:

[0158]

[0159] Among them, f CP(d) is the second frequency offset estimation value, angle(C(d)) represents the phase angle of the complex number C(d), C(d) is the estimated intermediate value, r(d+(K+P)×q+K+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+g, r * (d+(K+P)×q+K+g) is the conjugate complex number of r(d+(K+P)×q+K+g), r(d+(K+P)×q+K+P-G+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+P-G+g, r(d+K×J+P×q+g) is the sample data of the received signal at the time sample point d+K×J+P×q+g, r * (d+K×J+P×q+g) is the conjugate complex number of r(d+K×J+P×q+g), r(d+K×J+P×q+P-G+g) is the sample data of the received signal at the time sample point d+K×J+P×q+P-G+g, and G is the cyclic prefix length of the payload data block;

[0160] Calculate the intermediate estimate using the following formula

[0161]

[0162] in, represents rounding down, N and M are the integers that satisfy the equation A set of smallest positive integers;

[0163] From all possible combinations of n and m, find the value that makes The smallest {n,m} is recorded as {n',m'}, and the final frequency offset estimate Δf' is:

[0164]

[0165] The final offset estimation value Δf' is used to perform frequency offset compensation at the receiving end and the transmitting end.

[0166] In an exemplary embodiment, a receiver is provided, which includes a processor, a memory, an input / output interface (I / O) and a communication interface. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface is connected to the system bus via the input / output interface. The processor of the receiver is used to provide computing and control capabilities. The memory of the receiver includes a non-volatile storage medium and an internal memory. The input / output interface of the receiver is used to exchange information between the processor and an external device. The communication interface of the receiver is used to communicate with an external device via a network connection. When the computer program is executed by the processor, a signal capture and synchronization method is implemented.

[0167] In an exemplary embodiment, a receiver is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0168] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0169] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0170] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory or other media used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0171] The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, etc., but is not limited thereto.

[0172] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0173] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A signal capture and synchronization method, characterized in that: The signal capture and synchronization method comprises: Construct segmented training sequences; Inserting the segmented training sequence between the payload data blocks with cyclic prefixes to form a transmission data frame; Signal capture and timing are performed on the received signal obtained by transmitting the transmission data frame through the channel.

2. The signal capture and synchronization method according to claim 1, characterized in that: The step of constructing a segmented training sequence comprises: Construct J segmented training sequences S according to the following formula j : S j ={S j (k)},0≤j≤J-1,0≤k≤K-1; Among them, S j (k) represents the jth segment training sequence S j The kth sample data, K is the segmented training sequence S j Length; The step of inserting the segmented training sequence between payload data blocks with cyclic prefixes to form a transmission data frame comprises: The J segmented training sequences S j Insert Q payload data blocks D with cyclic prefix q Between, a transmission data frame is formed, in which: D q ={D q (p)},0≤q≤Q-1,0≤p≤P-1; In the above formula, D q (p) represents the qth payload data block D with a cyclic prefix q The pth sample data, P is the payload data block D with a cyclic prefix q The length of Q is greater than or equal to J-1.

3. The signal capture and synchronization method according to claim 2, characterized in that: The transmission data frame is: X={S0,D0,S1,D1,…,D J-2 ,S J-1 ,D J-1 ,D J ,…,D Q-1 }; Wherein, X is the transmission data frame.

4. The signal capture and synchronization method according to claim 1, characterized in that: Using a signal capture and synchronization method based on time diversity, signal capture and timing are performed on the received signal obtained by transmitting the transmission data frame through the channel; The signal capture and synchronization method based on time diversity is used to capture and time the received signal obtained by transmitting the transmission data frame through the channel, including: The sample data of the received signal at each time sample point is divided according to the order of the transmission data frame, and the sample data of a single time sample point is divided into J candidate segmented training sequences with an interval of P and a length of K, wherein: K is the length of the segmented training sequence, P is the length of the payload data block with a cyclic prefix, and J is the number of the segmented training sequences; Cross-correlate and sum each candidate segment training sequence of the sample data of the received signal at each time sample point with the corresponding local segment training sequence to obtain J segment correlation sum values ​​at each time sample point: Performing a fast Fourier transform operation on the J segment correlation sum values ​​at each time sample point, and determining the absolute maximum value of the fast Fourier transform operation value at each time sample point and its corresponding frequency index position; A peak curve is constructed by using the absolute maximum value of the fast Fourier transform operation value of each time sample point, wherein the abscissa of the peak curve is the time sample point, and the ordinate is the absolute maximum value of the fast Fourier transform operation value of each time sample point; Determine whether the absolute maximum value of the fast Fourier transform operation value of the peak curve is less than a preset threshold; if so, determine that the output state is an uncaptured state; otherwise, determine that the output state is a captured state, and select the time sample point corresponding to the maximum value of the peak curve as the synchronization starting point to complete time synchronization.

5. The signal capture and synchronization method according to claim 4, characterized in that: Also includes: When determining the absolute maximum value of the fast Fourier transform operation result of each time sample point, the frequency index position corresponding to the absolute maximum value is recorded; After the synchronization starting point is obtained, the frequency index position of the synchronization starting point is determined according to the record of the frequency index position corresponding to the maximum absolute value of the fast Fourier transform operation result of each time sample point.

6. The signal capture and synchronization method according to claim 5, characterized in that: Also includes: After determining the synchronization start point and its frequency index position, the carrier frequency difference between the receiving end and the transmitting end, namely the frequency offset, is estimated, and the estimated frequency offset estimation value is used to perform frequency offset compensation.

7. The signal capture and synchronization method according to claim 6, characterized in that: The frequency offset is estimated according to the following process: Using the obtained synchronization starting point and its frequency index position, the first frequency offset estimation is performed according to the following formula: Where d is the synchronization starting point, Ind_f(d) is the frequency index position of the synchronization starting point, and f ind(d) is the first frequency offset estimate, f s is the sampling frequency, J is the total number of the segmented training sequences, K is the length of the segmented training sequence, and P is the length of the payload data block with a cyclic prefix; Using the cyclic prefix of the payload data block in the constructed transmission data frame and the synchronization start point, the second frequency offset estimation is performed according to the following formula: Among them, f CP(d) is the second frequency offset estimation value, angle(C(d)) represents the phase angle of the complex number C(d), C(d) is the estimated intermediate value, r(d+(K+P)×q+K+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+g, r * (d+(K+P)×q+K+g) is the conjugate complex number of r(d+(K+P)×q+K+g), r(d+(K+P)×q+K+P-G+g) is the sample data of the received signal at the time sample point d+(K+P)×q+K+P-G+g, r(d+K×J+P×q+g) is the sample data of the received signal at the time sample point d+K×J+P×q+g, r * (d+K×J+P×q+g) is the conjugate complex number of r(d+K×J+P×q+g), r(d+K×J+P×q+P-G+g) is the sample data of the received signal at the time sample point d+K×J+P×q+P-G+g, and G is the cyclic prefix length of the payload data block; Calculate the intermediate estimate using the following formula in, represents rounding down, N and M are the integers that satisfy the equation A set of smallest positive integers; From all possible combinations of n and m, find the value that makes The smallest {n,m} is recorded as {n',m'}, and the final frequency offset estimate Δf' is: The final offset estimation value Δf' is used to perform frequency offset compensation at the receiving end and the transmitting end.

8. A receiver, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the signal capture and synchronization method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the signal acquisition and synchronization method described in any one of claims 1 to 7 are implemented.

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