5g mimo survey meter time synchronization method and system

Abstract

A 5G MIMO comprehensive tester time synchronization method and system, comprising: obtaining a local reference signal: generating a local reference signal S local , the local reference signal S local Is set to the sum of the pilot time domain symbols of all data streams: synchronization: each receiving channel independently carries out time synchronization processing, and the time synchronization point of each channel and the neighborhood signal-to-noise ratio value corresponding to the synchronization point are obtained; Signal-to-noise ratio decision: the time synchronization point of the channel corresponding to the maximum neighborhood signal-to-noise ratio value is selected as the total time synchronization point of the system; The above-mentioned 5G MIMO comprehensive tester time synchronization method and system effectively avoid the pseudo-peak superposition problem caused by the superposition of multi-stream signals by selecting the time synchronization sampling point with the maximum neighborhood SINR, effectively avoid the situation that the superposition of multi-stream data exceeds the peak value of the correct synchronization point, and improve the timing accuracy and precision.

Description

Technical Field

[0001] This invention relates to signal analysis and testing techniques for wireless systems, and particularly to a time synchronization method and system for a 5G MIMO comprehensive tester. Background Technology

[0002] A comprehensive test analyzer, also known as a comprehensive test and analysis instrument, is used for performance testing of wireless communication base stations or terminal products. It analyzes indicators such as in-band flatness, IQ (In-phase Quadrature) imbalance, DC bias, and EVM (Error Vector Magnitude) of the transmitted signal to provide feedback on the quality of the transmitted signal. It is widely used in the R&D and production line testing of wireless communication products. Common comprehensive test analyzers operate in single-port testing mode. Because they are unaffected by data streams from other ports, and the timing synchronization correlation peak is unique, timing synchronization schemes often employ time-domain correlation based on pilot signals (DMRS Demodulation Reference Signal). In 5G MIMO communication systems, as known from the 3GPP (3rd Generation Partnership) physical layer protocols, MIMO transmitted signals can reach up to four streams, and the DMRS of these four streams is the result of multiplying the same base sequence with a time-frequency orthogonal mask, exhibiting strong cross-correlation. Therefore, in a MIMO environment, the correlation peaks of multi-stream DMRS data are not unique, which may cause the value of the superimposed peaks to exceed the peak value of the correct time synchronization point. Simple threshold judgment will judge the peak point as the correct time synchronization point, resulting in a large timing error and making it impossible to correctly detect and provide feedback on various performance indicators of the transmitted signal.

[0003] In OFDM (Orthogonal Frequency Division Multiplexing) systems, common timing synchronization methods generally fall into two main categories: one uses pilot signals (DMRS) to correlate with the received sequence, and the other uses the cyclic prefix (CP) of the received signal to correlate with the received signal. Because the correlation method using DMRS signals with the local sequence is more accurate than the cyclic prefix method, it is more commonly used in integrated testers for single-stream signals.

[0004] Existing DMRS-based systems are all single-stream data testing systems, which exhibit weak cross-correlation between local sequences and fail to adequately consider the peak superposition problem caused by the strong cross-correlation of multi-stream data pilot time-domain signals in 5G MIMO scenarios. Furthermore, some multi-stream data systems employ the CP correlation method, which has poor accuracy and also exhibits poor cross-correlation between local multi-stream data, making it unsuitable for 5G MIMO systems. Summary of the Invention

[0005] Therefore, it is necessary to provide a time synchronization method for 5G MIMO comprehensive test instruments to improve timing accuracy.

[0006] Meanwhile, a time synchronization system for a 5G MIMO comprehensive test instrument is provided to improve timing accuracy.

[0007] A time synchronization method for a 5G MIMO comprehensive test instrument, comprising:

[0008] Acquire local reference signal: Generate local reference signal S local The number of data streams transmitted by the MIMO system is N. s The receiving antenna channel is N r Let r be the frequency domain pilot data of each first-order frequency domain after resource mapping and OFDM modulation. i (t), i = 1: N s ,t=1:N fft i represents each stream, t represents each sampling point, and N fft The length of the system's FFT transform, and the local reference signal S local Set as the sum of the time-domain signs of all data stream pilots:

[0009] Synchronization: Each receiving channel performs time synchronization processing independently, and the time synchronization point of each channel and the corresponding signal-to-noise ratio value of the neighborhood of the synchronization point are calculated;

[0010] Signal-to-noise ratio (SNR) decision: Select the time synchronization point of the channel with the largest neighborhood SNR value as the overall time synchronization point of the system.

[0011] In a preferred embodiment, the synchronization includes: performing time synchronization processing on the data from each receiving antenna independently, and determining the synchronization start sampling point t for each antenna. sync (j),j=1:N r , j represents the signal-to-noise ratio (SNR) SINR2(j) of the neighborhood corresponding to the j-th receiving antenna and the sampling point, j = 1:N r Let the received signal of each antenna be S. j (t),j=1:N r , t=1:N sample N sample This represents the number of sampling points for the signal, and the outer window length is winLen. out For N fft Each slide N fft One point.

[0012] In a preferred embodiment, the time synchronization process includes: dual sliding window time synchronization process.

[0013] In a preferred embodiment, the dual sliding window time synchronization process includes:

[0014] Data retrieval: Let wIdx be the window index. The received data that the wIdx-th window needs to process is S. temp The range of numbers to be selected is as follows:

[0015]

[0016] Sliding correlation: Transferring data stream S temp With local sequence S local Perform sliding correlation to obtain the correlation results. For a length of N fft sequence;

[0017] Peak storage: the calculated relevant energy Stored in peak memory P buff In the memory, the length is L store ;

[0018] Peak search: when the length L of the memory store >4N fft If the memory length does not meet the condition, the data retrieval step continues, and the aforementioned steps in the double sliding window time synchronization process are repeated. If the memory length meets the condition, the position of the maximum peak point in the memory is obtained and set as l. peak The following equation is satisfied:

[0019] P buff (l peak ) = max(P buff ),

[0020] Where max(x) represents finding the maximum value of x;

[0021] Threshold comparison: Calculate the overall signal-to-noise ratio (SINR1) and the neighborhood signal-to-noise ratio (SINR2) at the peak point.

[0022]

[0023] Where mean(x) represents the mean of x, if SINR1 > δ Thred Proceed to the next step, δ Thred This represents the threshold. If SINR1 does not exceed the threshold, the data retrieval step continues, resuming the previous steps in the dual sliding window time synchronization process. N cp Indicates the length of the cyclic prefix of the OFDM symbol;

[0024] Peak point determination: Pilot peak point determination: l dmrs =l peak +L store-4*N fft , where l dmrs The peak position related to the pilot symbol is denoted as l, and the synchronization point of the j-th receiving antenna is denoted as l. sync (j), j = 1: N r , l sync (j)=l dmrs -l offset , where l offset The starting position of the DMRS symbol within the entire OFDM symbol set, if l sync If (j) > 0, then output l. sync (j) and SINR2(j); if l sync If the value is less than 0, proceed to the data retrieval step and repeat the above steps of the double sliding window time synchronization process.

[0025] In a preferred embodiment, the signal-to-noise ratio (SNR) decision includes: selecting the time synchronization start point corresponding to the channel with the largest neighborhood SNR2(j) value as the system's time synchronization point. The condition is satisfied that SINR2(j) = max(SINR2).

[0026] A system for time synchronization of a 5G MIMO comprehensive test instrument, comprising:

[0027] Local reference signal acquisition module: generates local reference signal S local The number of data streams transmitted by the MIMO system is N. s The receiving antenna channel is N r Let r be the frequency domain pilot data of each first-order frequency domain after resource mapping and OFDM modulation. i (t), i = 1: N s ,t=1:N fft i represents each stream, t represents each sampling point, and N fft The length of the system's FFT transform, and the local reference signal S local Set as the sum of the time-domain signs of all data stream pilots:

[0028] Synchronization module: Each receiving channel performs time synchronization processing independently, and calculates the time synchronization point of each channel and the corresponding signal-to-noise ratio value of the neighborhood of the synchronization point;

[0029] Signal-to-noise ratio (SNR) decision module: Selects the time synchronization point of the channel with the largest neighborhood SNR value as the overall time synchronization point of the system.

[0030] In a preferred embodiment, the synchronization module includes: performing time synchronization processing independently on the data from each receiving antenna, and determining the synchronization start sampling point t for each antenna. sync (j),j=1:N r, j represents the signal-to-noise ratio (SNR) SINR2(j) of the neighborhood corresponding to the j-th receiving antenna and the sampling point, j = 1:N r Let the received signal of each antenna be S. j (t),j=1:N r , t=1:N sample N sample This represents the number of sampling points for the signal, and the outer window length is winLen. out For N fft Each slide N fft One point.

[0031] In a preferred embodiment, the time synchronization processing in the synchronization module includes a dual sliding window time synchronization processing module.

[0032] In a preferred embodiment, the dual sliding window time synchronization processing module includes:

[0033] Data retrieval unit: Let wIdx be the window index. The received data that the wIdx-th window needs to process is S. temp The range of numbers to be selected is as follows:

[0034]

[0035] Sliding correlated unit: Transfers data stream S temp With local sequence S local Perform sliding correlation to obtain the correlation results. For a length of N fft sequence;

[0036] Peak storage unit: This unit stores the calculated relevant energy. Stored in peak memory P buff In the memory, the length is L store ;

[0037] Peak search unit: When the length of the memory is greater than L store >4N fft If the memory length does not meet the condition, then the process proceeds to the data retrieval unit, continuing the processing of the preceding units in the dual sliding window time synchronization module. If the memory length meets the condition, the position of the maximum peak point in the memory is obtained and set as l. peak The following equation is satisfied:

[0038] P buff (l peak ) = max(P buff ),

[0039] Where max(x) represents finding the maximum value of x;

[0040] Threshold comparison unit: Calculates the overall signal-to-noise ratio (SINR1) and the neighborhood signal-to-noise ratio (SINR2) at the peak point.

[0041] Where mean(x) represents the mean of x, if SINR1 > δ Thred δ Thred Indicates the threshold, proceed to the next unit. If SINR1 does not exceed the threshold, proceed to the data retrieval unit and continue the processing of the previous units in the dual sliding window time synchronization processing module. N cp Indicates the length of the cyclic prefix of the OFDM symbol;

[0042] Peak point determination: Pilot peak point determination: l dmrs =l peak +L store -4*N fft , where l dmrs The peak position related to the pilot symbol is denoted as l, and the synchronization point of the j-th receiving antenna is denoted as l. sync (j), j = 1: N r , l sync (j)=l dmrs -l offset , where l offset The starting position of the DMRS symbol within the entire OFDM symbol set, if l sync If (j) > 0, then output l. sync (j) and SINR2(j); if l sync If the value is less than 0, then the data retrieval unit is entered, and the previous unit processing in the double sliding window time synchronization processing module is repeated.

[0043] In a preferred embodiment, the signal-to-noise ratio (SNR) decision module includes: selecting the time synchronization start point corresponding to the channel with the largest neighborhood SNR2(j) value as the system's time synchronization point. The condition is satisfied that SINR2(j) = max(SINR2).

[0044] The aforementioned 5G MIMO comprehensive tester time synchronization method and system effectively avoids the problem of pseudo-peak superposition caused by the superposition of multiple stream signals by selecting the time synchronization sampling point with the largest neighborhood SINR (signal-to-interference noise ratio), and effectively avoids the situation where the superposition of multiple stream data peaks exceeds the peak value of the correct synchronization point, thereby improving timing accuracy and precision. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a time synchronization system for a 5G MIMO comprehensive test instrument according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the peak storage structure of the present invention;

[0047] Figure 3 This is a correlation diagram of the time-domain signals of different data stream pilots in a specific embodiment of the present invention;

[0048] Figure 4 This is a demodulation constellation diagram for different data streams in a specific embodiment of the present invention. Detailed Implementation

[0049] The following examples are provided to help better understand the present invention, but are not intended to limit the invention.

[0050] A time synchronization method for a 5G MIMO comprehensive test instrument according to an embodiment of the present invention includes:

[0051] Acquire local reference signal: Generate local reference signal S local The number of data streams transmitted by the MIMO system is N. s The receiving antenna channel is N r Let r be the frequency domain pilot data of each first-order frequency domain after resource mapping and OFDM modulation. i (t), i = 1: N s ,t=1:N fft i represents each stream, t represents each sampling point, and N fft The length of the system's FFT transform, and the local reference signal S local Set as the sum of the time-domain signs of all data stream pilots:

[0052] Synchronization: Each receiving channel performs time synchronization processing independently, and the time synchronization point of each channel and the corresponding signal-to-noise ratio value of the neighborhood of the synchronization point are calculated;

[0053] Signal-to-noise ratio (SNR) decision: Select the time synchronization point of the channel with the largest neighborhood SNR value as the overall time synchronization point of the system.

[0054] Furthermore, the synchronization steps in this embodiment include: performing time synchronization processing independently on the data from each receiving antenna, and determining the synchronization start sampling point t for each antenna. sync (j),j=1:N r , j represents the signal-to-noise ratio (SNR) SINR2(j) of the neighborhood corresponding to the j-th receiving antenna and the sampling point, j = 1:N r Let the received signal of each antenna be S. j (t),j=1:N r , t=1:N sample N sample This represents the number of sampling points for the signal, and the outer window length is winLen. out For Nfft Each slide N fft One point.

[0055] Furthermore, the time synchronization processing in this embodiment includes: dual sliding window time synchronization processing.

[0056] Furthermore, the dual sliding window time synchronization processing in this embodiment includes:

[0057] Data retrieval: Let wIdx be the window index. The received data that the wIdx-th window needs to process is S. temp The range of numbers to be selected is as follows:

[0058]

[0059] Sliding correlation: Transferring data stream S temp With local sequence S local Perform sliding correlation to obtain the correlation results. For a length of N fft sequence;

[0060] Peak storage: the calculated relevant energy Stored in peak memory P buff In the memory, the length is L store Related energy Storage methods such as Figure 2 As shown;

[0061] Peak search: when the length L of the memory store >4N fft If the memory length does not meet the condition, the data retrieval step continues, and the above steps in the double sliding window time synchronization process are continued. If the memory length meets the condition, the position of the maximum peak point in the memory is obtained, and set as l. peak The following equation is satisfied:

[0062] P buff (l peak ) = max(P buff ),

[0063] Where max(x) represents finding the maximum value of x, max(P) buff ) indicates finding P buff The maximum value;

[0064] Threshold comparison: Calculate the overall signal-to-noise ratio (SINR1) and the neighborhood signal-to-noise ratio (SINR2) at the peak point.

[0065]

[0066] Where mean(x) represents the mean of x, mean(P(l)peak -N cp / 2):l peak +N cp / 2-1) means to find (P(l) peak -N cp / 2):l peak +N cp The mean of / 2-1),

[0067] mean(P(l peak -N fft / 2):l peak +N fft / 2-1) represents finding P(l) peak -N fft / 2):l peak +N fft / 2-1 mean, max(P(l peak -N cp ):l peak +N cp -1) indicates that (P(l) is being searched. peak -N cp ):l peak +N cp -1) Maximum value, max(P(l) peak -N fft / 2):l peak +N fft / 2-1) represents finding P(l) peak -N fft / 2):l peak +N fft / 2-1 maximum value, if SINR1>δ Thred Proceed to the next step, δ Thred This represents the threshold. If SINR1 does not exceed the threshold, the data retrieval step continues, and the previous steps in the dual sliding window time synchronization process are resumed. In this embodiment, N... cp Indicates the length of the cyclic prefix of the OFDM symbol;

[0068] Peak point determination: Pilot peak point determination: l dmrs =l peak +L store -4*N fft , where l dmrs The peak position related to the pilot symbol is denoted as l, and the synchronization point of the j-th receiving antenna is denoted as l. sync (j), j = 1: N r , l sync (j)=l dmrs -l offset , where l offset The starting position of the DMRS symbol within the entire OFDM symbol set, if lsync If (j) > 0, then output l. sync (j) and SINR2(j); if l sync If the value is less than 0, proceed to the data retrieval step and repeat the above steps of the double sliding window time synchronization process.

[0069] Furthermore, preferably, N s ≤N r .

[0070] Furthermore, the signal-to-noise ratio (SNR) decision step in this embodiment includes: selecting the time synchronization start point corresponding to the channel with the largest neighborhood SNR2(j) value as the system's time synchronization point. The condition is satisfied that SINR2(j) = max(SINR2).

[0071] The 5G MIMO comprehensive tester time synchronization method of the present invention is based on the DMRS sliding correlation method. It selects the time synchronization sampling point with the largest neighborhood SINR (signal to interference noise ratio), which can effectively avoid the problem of pseudo-peak superposition caused by the superposition of multiple stream signals.

[0072] like Figure 1 The 5G MIMO comprehensive test instrument time synchronization system shown in this embodiment of the present invention includes:

[0073] Local reference signal acquisition module: generates local reference signal S local The number of data streams transmitted by the MIMO system is N. s The receiving antenna channel is N r Let r be the frequency domain pilot data of each first-order frequency domain after resource mapping and OFDM modulation. i (t), i = 1: N s ,t=1:N fft i represents each stream, t represents each sampling point, and N fft The length of the system's FFT transform, and the local reference signal S local Set as the sum of the time-domain signs of all data stream pilots:

[0074] Synchronization module: Each receiving channel performs time synchronization processing independently, and calculates the time synchronization point of each channel and the corresponding signal-to-noise ratio value of the neighborhood of the synchronization point;

[0075] Signal-to-noise ratio (SNR) decision module: Selects the time synchronization point of the channel with the largest neighborhood SNR value as the overall time synchronization point of the system.

[0076] The synchronization module includes: performing independent time synchronization processing on the data from each receiving antenna, and determining the synchronization start sampling point t for each antenna. sync(j),j=1:N r , j represents the signal-to-noise ratio (SNR) SINR2(j) of the neighborhood corresponding to the j-th receiving antenna and the sampling point, j = 1:N r Let the received signal of each antenna be S. j (t),j=1:N r , t=1:N sample N sample This represents the number of sampling points for the signal, and the outer window length is winLen. out For N fft Each slide N fft One point.

[0077] Furthermore, the time synchronization processing in the synchronization module of this embodiment includes: a dual sliding window time synchronization processing module.

[0078] The dual sliding window time synchronization processing module in this embodiment includes:

[0079] Data retrieval unit: Let wIdx be the window index. The received data that the wIdx-th window needs to process is S. temp The range of numbers to be selected is as follows:

[0080]

[0081] Sliding correlated unit: Transfers data stream S temp With local sequence S local Perform sliding correlation to obtain the correlation results. For a length of N fft sequence;

[0082] Peak storage unit: This unit stores the calculated relevant energy. Stored in peak memory P buff In the memory, the length is L store Related energy Storage methods such as Figure 2 As shown;

[0083] Peak search unit: When the length of the memory is greater than L store >4N fft If the memory length does not meet the condition, then the process proceeds to the data retrieval unit, continuing the processing of the preceding units in the dual sliding window time synchronization module. If the memory length meets the condition, the position of the maximum peak point in the memory is obtained and set as l. peak The following equation is satisfied:

[0084] P buff (l peak ) = max(P buff ),

[0085] Where max(x) represents finding the maximum value of x;

[0086] Threshold comparison unit: Calculates the overall signal-to-noise ratio (SINR1) and the neighborhood signal-to-noise ratio (SINR2) at the peak point.

[0087] Where mean(x) represents the mean of x, if SINR1 > δ Thred Proceed to the next step, δ Thred This indicates the threshold. If SINR1 does not exceed the threshold, the data retrieval unit is entered, and the previous unit processing continues.

[0088] Peak point determination: Pilot peak point determination: l dmrs =l peak +L store -4*N fft , where l dmrs The peak position related to the pilot symbol is denoted as l, and the synchronization point of the j-th receiving antenna is denoted as l. sync (j), j = 1: N r , l sync (j)=l dmrs -l offset , where l offset The starting position of the DMRS symbol within the entire OFDM symbol set, if l sync If (j) > 0, then output l. sync (j) and SINR2(j); if l sync If the value is less than 0, then the data retrieval unit is entered, and the previous unit processing in the double sliding window time synchronization processing module is repeated.

[0089] Furthermore, the signal-to-noise ratio (SINR) decision module in this embodiment includes: selecting the time synchronization start point corresponding to the channel with the largest neighborhood SINR2(j) value as the system's time synchronization point: The condition is satisfied that SINR2(j) = max(SINR2).

[0090] The pilot signals for different ports of MIMO in 5G PUSCH pilot type 1 are shown in the table below. The table is Table 6.4.1.1.3-1 from the 3GPP 38.211 series.

[0091] Table 1: PUSCH DM-RS configuration type 1 parameter table

[0092]

[0093] As can be seen from the table, the base sequence of the DMRS signals at different ports is the same, as shown by the time-domain mask w. f (k') and frequency domain mask w t (l') Achieving orthogonality in the time and frequency domains. In cellular communication, since time synchronization can be achieved through PRACH, it is not necessary to use the DMRS correlation of service data to detect signals. Therefore, the cross-correlation of pilots between different ports has no impact on the system. However, in the field of measurement instruments, especially in non-signaling testing, there is no synchronization and access process. MIMO test instruments need to perform timing synchronization based on the received signal to detect the true starting sampling point of the signal. The data of each receiving channel is the result of the signals from different ports being superimposed through the channel. However, the strong cross-correlation of DMRS of multiple ports can cause the value after the pseudo-peak superposition to exceed the main peak value, resulting in a large timing synchronization error. When the error exceeds the CP length, even with time delay compensation, the test instrument still cannot demodulate correctly, thus failing to detect the true transmission quality of the signal. To avoid the impact of the pseudo-peak superposition of DMRS of multiple ports, the time synchronization method and system applicable to MIMO of this invention, based on DMRS sliding correlation, adds the judgment of the SINR value of the peak point neighborhood, and selects the time synchronization point corresponding to the channel with the largest neighborhood SINR as the correct time synchronization point of the system among all receiving channels. Since the SINR of the main peak's neighborhood is smaller than that of the secondary peak's neighborhood, this invention can effectively avoid the problem of secondary peak superposition caused by the superposition of MIMO multi-stream data.

[0094] A specific application example of the 5G MIMO time synchronization method and system of the present invention is as follows: The system has 4 transmit antennas, 4 receive antennas, and the DMRS port is selected as a DMRS type 2 PUSCH link [2 3 8 9]. The transmit signal format conforms to the 38.2x series, and other configurations are shown in Table 2.

[0095] Table 2 Link Configuration Parameters

[0096] SNR 30dB Frequency offset 500Hz TA [10006 10001 10004 10006] sampling points IQ offset 2 / 3 DC offset 3 / 2 MCS table 1 MCS 10 Additional DMRS 1

[0097] Obtaining the local reference signal: The pilot data of the 4-stream data, after RE mapping and OFDM signal acquisition, is as follows:

[0098]

[0099] The correlation diagram of the four-stream DMRS time-domain signal is as follows: Figure 3 Each stream of DMRS signal has a time-domain symbol length of 2048, and the autocorrelation peak is at point 2048. Figure 3 The first two graphs show that if a multi-stream signal is transmitted, at point 1706, the cross-correlation value of stream 1 and stream 2 is 29.9, the autocorrelation value of stream 1 is 44.5, and the summed value is 74.4, which exceeds the peak autocorrelation value of stream 1 (64). Figure 3 The same logic applies to the two figures below. Therefore, the system can easily misidentify point 1706 as the correct main peak, thus causing timing synchronization errors.

[0100] Synchronization: Each receiving antenna is independently time-synchronized based on a dual sliding window, resulting in four synchronization start points [10007 9660 10005 10007], with corresponding neighborhood SINR values ​​of [10.11 8.84 10.68 9.87].

[0101] Signal-to-noise ratio (SINR) decision: Select the synchronization start point 10005 of the third receiving antenna as the overall synchronization start point of the system. Combined with the time delay of each channel in the parameter configuration table, the timing synchronization error of each channel can be calculated as [1 4 1 1] sampling points.

[0102] The demodulation constellation diagram of the four streams after time delay compensation is as follows: Figure 4 As shown.

[0103] The EVM value for the fourth stream data is:

[0104] Stream 1 PUSCH aver EVM 0.0227982576％ Stream 1 DMRS EVM 0.0010404981％ Stream 2 PUSCH aver EVM 0.0287389091％ Stream 2 DMRS EVM 0.0008471429％ Stream 3 PUSCH aver EVM 0.0126314934％ Stream 3 DMRS EVM 0.0006887399％ Stream 4 PUSCH aver EVM 0.0404210705％ Stream 4 DMRS EVM 0.0021555776％

[0105] Based on the above-described preferred embodiments according to this application, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A 5G MIMO surveyor time synchronization method, characterized in that, Comprising: Obtaining local reference signal: generating local reference signal S local , the number of data streams sent by the MIMO system is N s , the number of receiving antenna channels is N r , let the data of each stream after resource mapping and OFDM modulation of the frequency domain pilot data be r i (t), i = 1:N s , t = 1:N fft , i represents each stream, t represents each sampling point, N fft is the length of the system fft transform, the local reference signal S local Let the sum of all data stream pilot time domain symbols be: Synchronization: each receiving channel independently carries out time synchronization processing, and finds out time synchronization points of each channel and neighborhood signal-to-noise ratio values corresponding to the synchronization points; The signal-to-noise ratio decision: selecting the time synchronization point of the channel corresponding to the maximum neighborhood signal-to-noise ratio value as the total time synchronization point of the system; the synchronization comprises: independently performing time synchronization processing on the data of each receiving antenna, and obtaining the synchronization starting sampling point t of each antenna sync (j), j = 1:N r , j represents the neighborhood signal-to-noise ratio SINR2(j), j = 1:N corresponding to the jth receiving antenna and the sampling point r , assuming that the received signal of each antenna is S j (t), j = 1:N r , t = 1:N sample , N sample , assuming that the outer window length winLen out is N fft , and N fft points are slid each time; the time synchronization processing comprises: double sliding window time synchronization processing; the double sliding window time synchronization processing comprises: Fetching: Let wldx be the index of the window, The received data that needs to be processed by the wldx-th window is S temp The fetching range is as follows: Slide correlation: slide the data stream S temp with the local sequence S local and get the result of correlation is a sequence with length N fft ; Peak storage: store the relevant energy computed in the peak storage P buff where the length of the memory is L store ; Peak search: when the length L of the memory store > 4N fft , peak judgment is performed, and if the length of the memory does not satisfy the condition, the data obtaining step is continued, the above steps are continued, and if the length of the memory satisfies the condition, the position of the maximum peak point in the memory is obtained and set as l peak , which satisfies the following equation: P buff (l peak )=max(P buff ), Wherein max(x) represents finding the maximum value of x; Threshold comparison: calculating the overall signal-to-noise ratio SINR1 value and the neighborhood signal-to-noise ratio SINR2 value at the peak point, Where mean(x) represents the mean of x, if SINR1 > δ Thred δ Thred Indicates the threshold, proceed to the next step. If SINR1 does not exceed the threshold, proceed to the data retrieval step, and continue the previous steps in the dual sliding window time synchronization processing. N cp Indicates the length of the cyclic prefix of the OFDM symbol; Peak point determination: pilot peak point determination: l dmrs = l peak + L store - 4*N fft , where l dmrs is the peak point position related to pilot symbols, the synchronization point of the jth receiving antenna is denoted as l sync (j), j = 1:N r , l sync (j) = l dmrs - 1 offset , where l offset is the starting position of the DMRS symbol in the entire OFDM symbol, if l sync (j) > 0, output l sync (j) and SINR2(j); if l sync (j) < 0, enter the data taking step, repeat the above steps of the double sliding window time synchronization processing.

2. The 5G MIMO metrology time synchronization method of claim 1, wherein, The signal-to-noise ratio decision comprises: selecting the time synchronization starting point corresponding to the channel with the maximum neighborhood signal-to-noise ratio SINR2(j) value as the time synchronization point of the system: SINR2(j) = max(SINR2) is satisfied.

3. A system for time synchronization of 5G MIMO metrology, characterized in that, Comprising: acquiring a local reference signal module: generating a local reference signal S local , the number of data streams sent by the MIMO system is N s , the number of receiving antenna channels is N r , let the data of each stream after resource mapping and OFDM modulation of the frequency domain pilot data be r i (t), i = 1:N s , t = 1:N fft , i represents each stream, t represents each sampling point, N fft is the length of the system fft transform, the local reference signal S local Let it be the sum of all data stream pilot time domain symbols: Synchronization module: each receiving channel independently carries out time synchronization processing, and finds out time synchronization points of each channel and neighborhood signal-to-noise ratio values corresponding to the synchronization points; Signal-to-noise ratio decision module: selecting the time synchronization point of the channel with the maximum neighborhood signal-to-noise ratio value as the total time synchronization point of the system; The synchronization module comprises: independently performing time synchronization processing on data of each receiving antenna, and obtaining a synchronization starting sampling point t sync (j), j = 1:N r , j represents a neighborhood signal-to-noise ratio SINR2(j), j = 1:N corresponding to the jth receiving antenna and a sampling point r , and assuming that the received signal of each antenna is S j (t), j = 1:N r , t = 1:N sample , N sample represents the number of sampling points of the signal, and assuming that the outer window length winLen out is N fft , and N fft points are slid each time; the time synchronization processing in the synchronization module comprises: a double sliding window time synchronization processing module; the double sliding window time synchronization processing module comprises: The data taking unit: let wIdx be the index of the window, The received data that the wIdxth window needs to process is S temp The data taking range is as follows: Slide correlation unit: slide correlation of data stream S temp with local sequence S local , obtaining the result after correlation is a sequence with length N fft ; Peak storage unit: stores the relevant energy obtained from the calculation stored in the peak storage P buff In this case, the length of the memory is L store ; Peak search unit: when the length of the memory is greater than L store > 4N fft , peak judgment is performed, if the memory length does not satisfy the condition, the data obtaining unit is entered, the previous unit processing is continued, if the memory length satisfies the condition, the position of the maximum peak point in the memory is obtained, and is set as l peak , the following formula is satisfied: P buff (l peak )=max(P buff ), Wherein max(x) represents finding the maximum value of x; Threshold comparison unit: calculating the overall signal-to-noise ratio SINR1 value and the neighborhood signal-to-noise ratio SINR2 value at the peak point, Where mean(x) represents the mean of x, if SINR1 > δ Thred δ Thred The threshold is indicated, and the process proceeds to the next unit. If SINR1 does not exceed the threshold, the process proceeds to the data retrieval unit and continues the processing in the previous unit of the dual sliding window time synchronization module. Peak point judging unit: pilot peak point judging: l dmrs = l peak + L store - 4*N fft , where l dmrs is the peak point position of pilot symbol correlation, the synchronization point of the jth receiving antenna is denoted as l sync (j), j = 1:N r , l sync (j) = l dmrs - l offset , where l offset is the starting position of DMRS symbol in the whole OFDM symbol, if l sync (j) > 0, output l sync (j) and SINR2(j); if l sync (j) < 0, enter the taking unit, repeat the previous unit processing in the double sliding window time synchronization processing module.

4. The system for 5G MIMO DAS time synchronization of claim 3, wherein, The signal-to-noise ratio judging module comprises: selecting a time synchronization starting point corresponding to a channel with a maximum neighborhood signal-to-noise ratio SINR2(j) value as a time synchronization point of the system: satisfies SINR2(j)=max(SINR2).

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