Multi-user burst detection method and device

Abstract

The invention relates to a multi-user burst detection method and device, and the method comprises the steps: carrying out the digital gain adjustment of a received signal, and obtaining an adjusted signal; determining a burst judgment threshold; performing frequency offset coarse compensation on the local synchronization sequence to obtain a plurality of coarse compensation sequences with the length of N; selecting a plurality of sampling point positions from the sampling point positions between the minimum sampling point position and the maximum sampling point position as starting sampling point positions; taking the position of each initial sampling point as a starting point, intercepting N continuous signal values from the adjusted signal, and obtaining an intercepted signal corresponding to the position of the initial sampling point; combining each coarse compensation sequence and the intercepted signal corresponding to the position of each initial sampling point in pairs to form a plurality of sequence-signal combination pairs; determining a correlation peak sequence of each sequence-signal combination pair; determining a peak value and a frequency offset estimation value of each sequence-signal combination pair; and detecting time domain initial positions and frequency offset estimation values of a plurality of users.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, more particularly to a multi-user burst detection method and device. BACKGROUND

[0002] VDES (Very High Frequency Data Exchange System) is a standard formulated by ITU-R (International Telecommunication Union Radio Communication Department) for water mobile communication, see R-REC-M.2092 protocol, which needs to support satellite-ship and ship-satellite communication. Satellite communication has the characteristics of wide coverage, long communication distance, large frequency offset range, and large number of users in the coverage area, which makes the communication environment relatively poor.

[0003] VDE (Wideband Very High Frequency Data Exchange) is a main way of high-speed data transmission in VDES, and there are multiple communication links, including link20, link25 and link32. Link20 is a random access channel of VDES, and multiple user collision access is inevitable. The multi-user collision recognition capability is directly related to the maximum capacity of the system.

[0004] Therefore, how to accurately identify each user on the same time-frequency resource is a technical problem to be solved in the field. SUMMARY

[0005] The purpose of the present application is to provide a multi-user burst detection method and device to accurately detect each user.

[0006] To achieve the above purpose, one aspect of the present application provides a multi-user burst detection method applied to the receiving end of a communication system, which comprises:

[0007] Performing digital gain adjustment on the received signal to obtain an adjusted signal;

[0008] Determining a burst decision threshold based on the adjusted signal;

[0009] Performing coarse frequency offset compensation on the local synchronization sequence in the maximum frequency offset range with a preset frequency offset compensation step to obtain a plurality of coarse compensation sequences, each coarse compensation sequence corresponding to a different frequency offset, and the length of each coarse compensation sequence being N;

[0010] Obtaining the minimum sampling point position based on the minimum time delay and the maximum sampling point position based on the maximum time delay, selecting a plurality of sampling point positions as the starting sampling point positions from the minimum sampling point position and the maximum sampling point position in a preset value interval, and for each starting sampling point position, taking the starting sampling point position as the starting point to cut N continuous signal values from the adjusted signal to obtain the cut signal corresponding to the starting sampling point position;

[0011] Each coarse compensation sequence and the truncated signal corresponding to each starting sampling point position are paired to form several sequence-signal combination pairs. The number of sequence-signal combination pairs is the product of the number of coarse compensation sequences and the number of starting sampling points. For each sequence-signal combination pair, the correlation peak sequence of the sequence-signal combination pair is determined based on the coarse compensation sequence and the truncated signal corresponding to the starting sampling point position.

[0012] Based on the correlation peak sequence of each sequence-signal combination pair, determine the peak value and frequency offset estimate of the sequence-signal combination pair;

[0013] Based on the burst decision threshold and the peak and frequency offset estimates of each sequence-signal combination pair, the time-domain start position and frequency offset estimates of multiple users were detected.

[0014] Optionally, the received signal is digitally gain-adjusted to obtain the adjusted signal, specifically including:

[0015] The maximum time delay K consecutive signal values ​​are extracted from the received signal to form the maximum time delay truncation signal;

[0016] Calculate the average signal power based on the signal intercepted with the maximum time delay;

[0017] The difference between the preset target power and the average signal power is obtained as the digital gain adjustment factor;

[0018] The received signal is digitally gained by adjusting the digital gain of the digital gain adjustment factor to obtain the adjusted signal.

[0019] Optionally, the sudden decision threshold is determined based on the adjusted signal, specifically including:

[0020] N consecutive signal values ​​after the maximum time delay are extracted from the adjusted signal to form the noise power signal;

[0021] Calculate the power of the noise power signal to obtain the noise power;

[0022] Multiply the noise power by the preset noise threshold to obtain the burst decision threshold.

[0023] Optionally, for each sequence-signal combination pair, based on the coarse compensation sequence of the sequence-signal combination pair and the truncated signal corresponding to the starting sampling point position, the correlation peak sequence of the sequence-signal combination pair is determined, specifically including:

[0024] For each sequence-signal combination pair, the coarse compensation sequence of the sequence-signal combination pair is divided into multiple subsequences of equal length in a continuous order. The i-th subsequence is composed of the (i-1)×n+1 to the i×n elements of the coarse compensation sequence, where n is the length of the subsequence, i is a positive integer and i≤N / n;

[0025] The intercepted signal corresponding to the starting sampling point of the sequence-signal combination is divided into multiple sub-signals of equal length in a continuous sequence. The i-th sub-signal is composed of the (i-1)×n+1 to the i×n signal values ​​of the intercepted signal corresponding to the starting sampling point.

[0026] Determine the correlation peak sequence of the sequence-signal combination pair, wherein the length of the correlation peak sequence is N / n and the i-th element of the correlation peak sequence is obtained by correlation between the i-th sub-sequence of the coarse compensation sequence of the sequence-signal combination pair and the i-th sub-signal corresponding to the starting sampling point position of the sequence-signal combination pair.

[0027] Optionally, based on the correlation peak sequence of each sequence-signal combination pair, the peak value and frequency offset estimate of the sequence-signal combination pair are determined, specifically including:

[0028] The correlation peak sequence of each sequence-signal combination pair is transformed from the time domain to the frequency domain to obtain the frequency domain correlation peak sequence of each sequence-signal combination pair;

[0029] The frequency domain correlation peak sequence of each sequence-signal combination pair is shifted by one subcarrier and then added to the frequency domain correlation peak sequence of the same sequence-signal combination pair to obtain the processed frequency domain correlation peak sequence of the sequence-signal combination pair.

[0030] Obtain the peak value and the interval between the peak value and the center point of the processed frequency domain correlation peak sequence for each sequence-signal combination pair;

[0031] The interval between the peak position and the center point of the processed frequency domain correlation peak sequence of each sequence-signal combination pair is compared with a preset threshold. If the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of the sequence-signal combination pair is greater than the preset threshold, then the peak value of the sequence-signal combination pair is 0; if the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of the sequence-signal combination pair is less than or equal to the preset threshold, then the peak value of the sequence-signal combination pair is equal to the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair.

[0032] The frequency offset estimate of each sequence-signal combination pair is determined based on the interval between the peak position and the center point of the processed frequency domain correlation peak sequence.

[0033] Optionally, based on the burst decision threshold and the peak and frequency offset estimates of each sequence-signal combination pair, the time-domain start position and frequency offset estimates of multiple users are detected, specifically including:

[0034] For each of the peak values ​​of each sequence-signal combination pair, the peak value of the sequence-signal combination pair is compared with the burst decision threshold; if the peak value of the sequence-signal combination pair is less than the burst decision threshold, the peak value of the sequence-signal combination pair is set to 0; if the peak value of the sequence-signal combination pair is greater than the burst decision threshold, the peak value of the sequence-signal combination pair remains unchanged; thus obtaining the peak value after decision for each sequence-signal combination pair.

[0035] The maximum value of the peak value after the decision of each sequence-signal combination pair is obtained as the maximum peak value;

[0036] Determine if the maximum peak value is greater than 0;

[0037] If not, no user was detected, and the detection ends;

[0038] If so, a user is detected, a user index is assigned to the user; the starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the user's time domain starting position, and the frequency offset estimate of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the user's frequency offset;

[0039] When a user is detected, the peak value of the sequence-signal combination pair near the maximum peak value is set to 0, and the peak value of each sequence-signal combination pair after the decision is updated. Then, the maximum peak value of each sequence-signal combination pair after the decision is re-acquired, and the maximum peak value is re-determined to be greater than 0, until the detection ends or the number of all detected users reaches the preset number.

[0040] Another aspect of the present invention provides a multi-user burst detection device, applied to the receiving end of a communication system, the device comprising:

[0041] The gain adjustment module is used to digitally adjust the gain of the received signal to obtain the adjusted signal.

[0042] The first determining module is used to determine the burst decision threshold based on the adjusted signal;

[0043] The coarse compensation module is used to perform coarse frequency offset compensation on the local synchronization sequence within the maximum frequency offset range with a preset frequency offset compensation step size, so as to obtain multiple coarse compensation sequences, each coarse compensation sequence corresponding to a different frequency offset, and the length of each coarse compensation sequence is N.

[0044] The interception module is used to obtain the minimum sampling point position based on the minimum time delay and the maximum sampling point position based on the maximum time delay. Starting from the minimum sampling point position, it sequentially selects multiple sampling point positions from the sampling point positions between the minimum and maximum sampling point positions at preset value intervals, as each starting sampling point position. For each starting sampling point position, it intercepts N consecutive signal values ​​from the adjusted signal, using that starting sampling point position as the starting point, to obtain the intercepted signal corresponding to that starting sampling point position.

[0045] The second determining module is used to combine each coarse compensation sequence and the truncated signal corresponding to each starting sampling point position in pairs to form a number of sequence-signal combination pairs. The number of sequence-signal combination pairs is the product of the number of coarse compensation sequences and the number of starting sampling points. For each sequence-signal combination pair, based on the coarse compensation sequence and the truncated signal corresponding to the starting sampling point position of the sequence-signal combination pair, the relevant peak sequence of the sequence-signal combination pair is determined.

[0046] The third determining module is used to determine the peak value and frequency offset estimate of each sequence-signal combination pair based on the correlation peak sequence of each sequence-signal combination pair.

[0047] The detection module is used to detect the time-domain start position and frequency offset estimate of multiple users based on the burst decision threshold and the peak and frequency offset estimates of each sequence-signal combination pair.

[0048] Optionally, the received signal is digitally gain-adjusted to obtain the adjusted signal, specifically including:

[0049] The maximum time delay K consecutive signal values ​​are extracted from the received signal to form the maximum time delay truncation signal;

[0050] Calculate the average signal power based on the signal intercepted with the maximum time delay;

[0051] The difference between the preset target power and the average signal power is obtained as the digital gain adjustment factor;

[0052] The received signal is digitally gained by adjusting the digital gain of the digital gain adjustment factor to obtain the adjusted signal.

[0053] Optionally, the sudden decision threshold is determined based on the adjusted signal, specifically including:

[0054] N consecutive signal values ​​after the maximum time delay are extracted from the adjusted signal to form the noise power signal;

[0055] Calculate the power of the noise power signal to obtain the noise power;

[0056] Multiply the noise power by the preset noise threshold to obtain the burst decision threshold.

[0057] Optionally, for each sequence-signal combination pair, based on the coarse compensation sequence of the sequence-signal combination pair and the truncated signal corresponding to the starting sampling point position, the correlation peak sequence of the sequence-signal combination pair is determined, specifically including:

[0058] For each sequence-signal combination pair, the coarse compensation sequence of the sequence-signal combination pair is divided into multiple subsequences of equal length in a continuous order. The i-th subsequence is composed of the (i-1)×n+1 to the i×n elements of the coarse compensation sequence, where n is the length of the subsequence, i is a positive integer and i≤N / n;

[0059] The intercepted signal corresponding to the starting sampling point of the sequence-signal combination is divided into multiple sub-signals of equal length in a continuous sequence. The i-th sub-signal is composed of the (i-1)×n+1 to the i×n signal values ​​of the intercepted signal corresponding to the starting sampling point.

[0060] Determine the correlation peak sequence of the sequence-signal combination pair, wherein the length of the correlation peak sequence is N / n and the i-th element of the correlation peak sequence is obtained by correlation between the i-th sub-sequence of the coarse compensation sequence of the sequence-signal combination pair and the i-th sub-signal corresponding to the starting sampling point position of the sequence-signal combination pair.

[0061] Optionally, based on the correlation peak sequence of each sequence-signal combination pair, the peak value and frequency offset estimate of the sequence-signal combination pair are determined, specifically including:

[0062] The correlation peak sequence of each sequence-signal combination pair is transformed from the time domain to the frequency domain to obtain the frequency domain correlation peak sequence of each sequence-signal combination pair;

[0063] The frequency domain correlation peak sequence of each sequence-signal combination pair is shifted by one subcarrier and then added to the frequency domain correlation peak sequence of the same sequence-signal combination pair to obtain the processed frequency domain correlation peak sequence of the sequence-signal combination pair.

[0064] Obtain the peak value and the interval between the peak value and the center point of the processed frequency domain correlation peak sequence for each sequence-signal combination pair;

[0065] The interval between the peak position and the center point of the processed frequency domain correlation peak sequence of each sequence-signal combination pair is compared with a preset threshold. If the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of the sequence-signal combination pair is greater than the preset threshold, then the peak value of the sequence-signal combination pair is 0; if the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of the sequence-signal combination pair is less than or equal to the preset threshold, then the peak value of the sequence-signal combination pair is equal to the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair.

[0066] The frequency offset estimate of each sequence-signal combination pair is determined based on the interval between the peak position and the center point of the processed frequency domain correlation peak sequence.

[0067] Optionally, based on the burst decision threshold and the peak and frequency offset estimates of each sequence-signal combination pair, the time-domain start position and frequency offset estimates of multiple users are detected, specifically including:

[0068] For each of the peak values ​​of each sequence-signal combination pair, the peak value of the sequence-signal combination pair is compared with the burst decision threshold; if the peak value of the sequence-signal combination pair is less than the burst decision threshold, the peak value of the sequence-signal combination pair is set to 0; if the peak value of the sequence-signal combination pair is greater than the burst decision threshold, the peak value of the sequence-signal combination pair remains unchanged; thus obtaining the peak value after decision for each sequence-signal combination pair.

[0069] The maximum value of the peak value after the decision of each sequence-signal combination pair is obtained as the maximum peak value;

[0070] Determine if the maximum peak value is greater than 0;

[0071] If not, no user was detected, and the detection ends;

[0072] If so, a user is detected, a user index is assigned to the user; the starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the user's time domain starting position, and the frequency offset estimate of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the user's frequency offset;

[0073] When a user is detected, the peak value of the sequence-signal combination pair near the maximum peak value is set to 0, and the peak value of each sequence-signal combination pair after the decision is updated. Then, the maximum peak value of each sequence-signal combination pair after the decision is re-acquired, and the maximum peak value is re-determined to be greater than 0, until the detection ends or the number of all detected users reaches the preset number. Attached Figure Description

[0074] Figure 1This is a flowchart of a multi-user burst detection method according to an embodiment of the present invention;

[0075] Figure 2 This is a structural block diagram of a multi-user burst detection device according to an embodiment of the present invention. Detailed Implementation

[0076] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0077] In maritime mobile communication networks, different users (such as ships) transmit signals, which include their respective navigation information. The onboard VDES (i.e., the receiver) can receive these signals. The signals received by the onboard VDES can be called received signals. The received signals are time-domain signals, which are collected at a preset sampling rate. Therefore, they include signal values ​​from different sampling points. The multi-user burst detection method identifies short burst signals randomly transmitted by multiple users on the same time-frequency resource and obtains the key basic information of each user's signal, paving the way for subsequent separation and demodulation of each user's data.

[0078] like Figure 1 As shown, this embodiment of the invention provides a multi-user burst detection method, which includes the following steps:

[0079] S100: Perform digital gain adjustment on the received signal to obtain the adjusted signal.

[0080] In some embodiments, step S100 specifically includes S110-S140:

[0081] S110: Extract K consecutive signal values ​​after the maximum time delay from the received signal to form the maximum time delay truncation signal.

[0082] Assume the received signal is The maximum time delay truncation signal is ,but:

[0083]

[0084] Where m is the time index, corresponding to the sampling point position of the received signal, and slc is the sampling point position corresponding to the maximum signal strength. Taking a maximum delay of 11.68ms and a baseband sampling rate of 33.6kHz as an example, the received signal is obtained by sampling at 4 times the baseband sampling rate. If the sampling point corresponding to the maximum time delay is the 1569th sampling point, then the starting point of the signal intercepted for the maximum time delay is the 1570th sampling point.

[0085] Assuming the bit width of the digital field is 16 bits, then K can take the value 256.

[0086] S120: Calculate the average signal power based on the signal intercepted with the maximum time delay.

[0087] The energy of the signal with the maximum time delay is:

[0088]

[0089] The formula for calculating average signal power is:

[0090]

[0091] in, P represents the average signal power, where P is the power of a 1-bit signal, for example, P = 6.02 dB / bit.

[0092] S130: Determine the digital gain adjustment factor based on the average signal power and the preset target power.

[0093] The digital gain adjustment factor is denoted as The calculation formula is as follows:

[0094]

[0095] in, The target power can be set as needed, for example, to 11.

[0096] S140: The received signal is digitally gained based on the digital gain adjustment factor to obtain the adjusted signal.

[0097] The adjusted signal is denoted as The calculation formula is as follows:

[0098]

[0099] Since digital gain adjustment only enhances or attenuates each signal value without changing its time-domain order, the adjusted signal has the same time-domain order as the received signal.

[0100] S200: Determines the burst decision threshold based on the adjusted signal.

[0101] In some embodiments, step S200 specifically includes S210-S230:

[0102] S210: Extract N consecutive signal values ​​after the maximum time delay from the adjusted signal to form a noise power signal;

[0103] S220: Calculate the power of the noise power signal to obtain the noise power;

[0104] S230: Determine the burst decision threshold based on noise power and a preset noise threshold.

[0105] Link20 supports multi-user detection. The user with the highest signal energy can be considered noise relative to other users. Therefore, the noise power can be calculated using N points after the maximum time delay, where N is the length of the local synchronization sequence, for example, N=3072. The noise power signal can be denoted as... The noise power can be denoted as The threshold for sudden judgments can be denoted as The noise threshold can be denoted as TH, and its calculation formula is:

[0106]

[0107]

[0108]

[0109] The noise threshold TH can be obtained from simulation; for example, TH = 0.825 can be chosen.

[0110] S300: With a preset frequency offset compensation step size, perform coarse frequency offset compensation on the local synchronization sequence within the maximum frequency offset range to obtain multiple coarse compensation sequences. Each coarse compensation sequence corresponds to a different frequency offset, and the length of each coarse compensation sequence is N.

[0111] Let the frequency offset compensation step size be denoted as ,by Taking a maximum frequency deviation range of ±5.2kHz as an example, 13 coarse compensation frequency points (i.e., frequency deviations) can be obtained, denoted as Hz. , This means that starting from a frequency of -4800Hz and ending at 4800Hz, a value is taken every 800Hz to obtain 13 coarse compensation frequency points. Each coarse compensation frequency point is used to compensate the local synchronization sequence to obtain the coarse compensation sequence corresponding to each coarse compensation frequency point, resulting in a total of 13 coarse compensation sequences.

[0112] Let the local synchronization sequence be denoted as The coarse compensation sequence is denoted as ,in, For frequency offset indexes, for example, , This indicates the first frequency offset, which is -4800Hz. This indicates the second frequency offset, which is -4000Hz, and so on; For frequency offset index The coarse compensation sequence corresponding to the frequency offset is calculated using the following formula:

[0113]

[0114] Where j is the imaginary unit and t is the time corresponding to the sampling point x.

[0115] Each coarse compensation sequence can be pre-calculated based on the local synchronization sequence and stored locally. Then, when performing user identification, each coarse compensation sequence can be directly called without real-time calculation, thereby reducing the consumption of logical resources.

[0116] It is understandable that coarse frequency offset compensation can also be a pre-compensation for the adjusted signal. The compensation method is equivalent to the above method. When compensating, only a portion of the data can be compensated. For example, if the maximum delay is 11.68ms, only 1570+3072=4642 signal values ​​can be compensated to reduce resource consumption.

[0117] S400: Obtain the minimum sampling point position based on the minimum time delay, and obtain the maximum sampling point position based on the maximum time delay. Starting from the minimum sampling point position, select multiple sampling point positions sequentially from the sampling point positions between the minimum and maximum sampling point positions according to a preset value interval, as each starting sampling point position; for each starting sampling point position, extract N consecutive signal values ​​from the adjusted signal, using the starting sampling point position as the starting point, to obtain the intercepted signal corresponding to the starting sampling point position.

[0118] Latency refers to the time difference between a user's transmitted signal and the time difference between the transmitted signal and its reception by the onboard VDES. The latency varies depending on the user's signal transmission. The minimum latency is the latency of the signal arriving first, and the maximum latency is the latency of the signal arriving last. Within the time interval between the minimum and maximum latency, signals from different users can be received at any point between these two times; that is, the origin of different user signals can be anywhere between the minimum and maximum latency.

[0119] Let the preset interval be d. The minimum sampling point position can be obtained based on the minimum time delay, and the maximum sampling point position can be obtained based on the maximum time delay. The starting point of different user signals can be any sampling point position between the minimum sampling point position and the maximum sampling point position. Therefore, multiple sampling point positions can be selected from the two at equal intervals d as each starting sampling point position. Then, with each starting sampling point position as the starting point, N consecutive signal values ​​are extracted from the adjusted signal to obtain the extracted signal corresponding to each starting sampling point position.

[0120] For example, if the minimum delay is 3ms, the maximum delay is 11.68ms, and the received signal sampling rate is 4 times the baseband sampling rate: 4 × 33.6KHz, then the location of the minimum sampling point is: The location of the maximum sampling point is: The preset value interval is 3, then the positions of each starting sampling point are: There are a total of 389 initial sampling points.

[0121] The intercepted signal corresponding to each initial sampling point position can be denoted as: The calculation formula is as follows:

[0122]

[0123] S500: Combine each coarse compensation sequence with the truncated signal corresponding to each starting sampling point position in pairs to form several sequence-signal combination pairs. The number of sequence-signal combination pairs is the product of the number of coarse compensation sequences and the number of starting sampling points. For each sequence-signal combination pair, determine the correlation peak sequence of the sequence-signal combination pair based on the coarse compensation sequence and the truncated signal corresponding to the starting sampling point position.

[0124] Combining each coarse compensation sequence with the truncated signal corresponding to each starting sampling point means that each coarse compensation sequence is paired with the truncated signal corresponding to each starting sampling point to form a sequence-signal combination pair. This results in several sequence-signal combination pairs, each consisting of a coarse compensation sequence and a truncated signal corresponding to a starting sampling point. Each sequence-signal combination pair is different from the others. For example, if there are 13 coarse compensation sequences and 389 starting sampling points, then there are a total of 13 × 389 = 5057 sequence-signal combination pairs.

[0125] In some embodiments, for each sequence-signal combination pair, based on the coarse compensation sequence of the sequence-signal combination pair and the truncated signal corresponding to the starting sampling point position, the relevant peak sequence of the sequence-signal combination pair is determined, specifically including:

[0126] For each sequence-signal combination pair, the coarse compensation sequence of the sequence-signal combination pair is divided into multiple subsequences of equal length in a continuous order. The i-th subsequence is composed of the (i-1)×n+1 to the i×n elements of the coarse compensation sequence, where n is the length of the subsequence, i is a positive integer and i≤N / n;

[0127] The intercepted signal corresponding to the starting sampling point of the sequence-signal combination is divided into multiple sub-signals of equal length in a continuous sequence. The i-th sub-signal is composed of the (i-1)×n+1 to the i×n signal values ​​of the intercepted signal corresponding to the starting sampling point.

[0128] Determine the correlation peak sequence of the sequence-signal combination pair, wherein the length of the correlation peak sequence is N / n and the i-th element of the correlation peak sequence is obtained by calculating the correlation value of the i-th sub-sequence of the coarse compensation sequence of the sequence-signal combination pair and the i-th sub-signal corresponding to the starting sampling point position of the sequence-signal combination pair.

[0129] The correlation peak sequence of the sequence-signal combination pair can be denoted as: It satisfies the following relationship (i.e., the formula for calculating the correlation value):

[0130]

[0131] Indicates frequency offset index The correlation peak sequence of the sequence consisting of the corresponding coarse compensation sequence and the truncated signal corresponding to the starting sampling point position s.

[0132] S600: Based on the correlation peak sequence of each sequence-signal combination pair, determine the peak value and frequency offset estimate of that sequence-signal combination pair.

[0133] In some embodiments, step S600 specifically includes the following steps S610-S650:

[0134] S610: Transform the correlation peak sequence of each sequence-signal combination pair from the time domain to the frequency domain to obtain the frequency domain correlation peak sequence of each sequence-signal combination pair.

[0135] For each sequence-signal combination pair of length N / n, the correlation peak sequence can be adjusted by padding it with zeros at the end. Then, perform the following steps on the length-adjusted sequence: Point Fast Fourier Transform is used to transform the signal from the time domain to the frequency domain, and the frequency domain correlation peak sequence of each sequence-signal combination pair is denoted as... It satisfies the following relationship:

[0136]

[0137] The frequency interval between any two adjacent elements is denoted as F. , Wherein is the baseband sampling rate.

[0138] S620: The frequency domain correlation peak sequence of each sequence-signal combination pair is offset by one subcarrier and then added to the frequency domain correlation peak sequence of the sequence-signal combination pair to obtain the processed frequency domain correlation peak sequence of the sequence-signal combination pair.

[0139] The frequency domain correlation peak sequence after processing the sequence-signal combination pair can be denoted as , which satisfies the following relationship:

[0140]

[0141] The length N / n of the correlation peak sequence and the frequency offset compensation step size They exhibit a positive correlation. To ensure user recognition performance, they can satisfy the following relationship:

[0142]

[0143] Where M is the baseband sampling rate factor. At Hz, Values ​​from 48 to 64 are acceptable. Easier to implement, when Configurable .

[0144] S630: Obtain the peak value and the interval between the peak value and the center point of the processed frequency domain correlation peak sequence for each sequence-signal combination pair.

[0145] After obtaining the processed frequency domain correlation peak sequence of each sequence-signal combination pair, we can find its maximum element value, which is its peak value. The location of the maximum element value is the location of the peak value. Subtracting the center point (i.e., the center position) from the location of the peak value gives the interval between the location of the peak value and the center point.

[0146] S640: Compare the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of each sequence-signal combination pair with a preset threshold. If the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of the sequence-signal combination pair is greater than the preset threshold, then the peak value of the sequence-signal combination pair is 0; if the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of the sequence-signal combination pair is less than or equal to the preset threshold, then the peak value of the sequence-signal combination pair is equal to the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair.

[0147] The preset threshold can be denoted as It satisfies the following relationship:

[0148]

[0149] If the distance between the peak location and the center point is greater than a preset threshold, the result is considered unreliable and is therefore set to 0 to prevent false detections. Conversely, if the distance is less than a preset threshold, the result is considered reliable and the peak value is retained as the basis for subsequent user detection.

[0150] S650: Determine the frequency offset estimate of the sequence-signal combination pair based on the interval between the peak position and the center point of the processed frequency domain correlation peak sequence of each sequence-signal combination pair.

[0151] The frequency offset estimate for each sequence-signal combination pair is denoted as... It satisfies the following relationship:

[0152]

[0153] The peak values ​​of each sequence-signal combination pair can be stored in a two-dimensional search matrix. In this process, the frequency offset estimates of each sequence-signal combination pair can be stored in the frequency offset matrix. In the middle. That is, each. and Each corresponds to a peak value and a frequency offset estimate.

[0154] S700: Based on the burst decision threshold and the peak and frequency offset estimates of each sequence-signal combination pair, the time-domain start position and frequency offset estimates of multiple users are detected.

[0155] In some embodiments, step S700 specifically includes the following steps S710-S760:

[0156] S710: For each of the peak values ​​of each sequence-signal combination pair, compare the peak value of the sequence-signal combination pair with the burst decision threshold; if the peak value of the sequence-signal combination pair is less than the burst decision threshold, then set the peak value of the sequence-signal combination pair to 0; if the peak value of the sequence-signal combination pair is greater than the burst decision threshold, then the peak value of the sequence-signal combination pair remains unchanged; so as to obtain the peak value after the decision of each sequence-signal combination pair.

[0157] S720: Obtain the maximum value of the peak value after the decision of each sequence-signal combination pair, and use it as the maximum peak value.

[0158] S730: Determine if the maximum peak value is greater than 0.

[0159] S740: If not, no user was detected, and the detection ends.

[0160] If the maximum peak value is less than 0, then all peak values ​​are 0, indicating that no user was detected, and the detection ends.

[0161] S750: If yes, then a user is detected, a user index is assigned to the user; the starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the user's time domain starting position, and the frequency offset estimate of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the user's frequency offset.

[0162] If the maximum peak value is greater than 0, it means that a user has been detected. A user index can be assigned to the user. The starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value is the starting position of the user in the time domain. The frequency offset estimate of the sequence-signal combination pair corresponding to the maximum peak value is the frequency offset of the user.

[0163] S760: Set the peak value of the sequence-signal combination pairs near the sequence-signal combination pair corresponding to the maximum peak value to 0, and obtain the peak value of each sequence-signal combination pair after the decision; repeat steps S720-S760 until the detection ends or the number of all detected users reaches the preset number.

[0164] Specifically, in step S760, the frequency index of the sequence-signal combination pair corresponding to the maximum peak value can be one point before and after the starting sampling point. The peak values ​​of the sequence-signal combination pairs at each point are set to zero (the baseband sampling rate multiple M divided by the sampling interval d, rounded up). This yields the updated peak values ​​of each sequence-signal combination pair after the decision. The purpose of this is to remove the correlation values ​​of already detected users and avoid duplicate detection. This process can be expressed as follows:

[0165]

[0166] in, This is the frequency index of the coarsely compensated sequence for the sequence-signal combination pair corresponding to the maximum peak value. This represents the starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value.

[0167] After obtaining the peak values ​​of each updated sequence-signal combination pair, the maximum peak value can be retrieved again, and user detection can be performed again based on the maximum peak value until the detection ends or the number of detected users reaches the preset number.

[0168] Ultimately, the method of this invention can detect multiple users, as well as the time-domain start position and frequency offset of each user.

[0169] It should be noted that although the method of the present invention is described in the above embodiments using a baseband sampling rate of 4 times that of the link20 channel as an example, it is understood that the method of the present invention is not limited to the link20 channel, but can also be applied to other link channels and other multiples of baseband sampling rates. Furthermore, the method of the present invention is not limited to communication systems using the VDES protocol, but can also be applied to other communication systems; specifically, it can be applied to the receiving end of any communication system.

[0170] The multi-user burst detection method of this invention reduces resource consumption by adjusting the amplitude of the received signal to a suitable range through digital gain adjustment; it first performs coarse frequency offset compensation on the local synchronization sequence and correlates it with the received signal, then groups and merges the correlation values, performs small-point FFT operation, finds the maximum correlation value, thereby reducing the impact of residual frequency offset on the correlation peak, ensuring signal recognition accuracy at low signal-to-noise ratio while reducing implementation complexity and resource consumption.

[0171] like Figure 2 As shown, this embodiment of the invention also provides a multi-user burst detection device, which is applied to the receiving end of a communication system. The device includes a gain adjustment module 10, a first determination module 20, a coarse compensation module 30, a truncation module 40, a second determination module 50, a third determination module 60, and a detection module 70.

[0172] The gain adjustment module 10 is used to digitally adjust the gain of the received signal to obtain the adjusted signal.

[0173] The first determining module 20 is used to determine the burst decision threshold based on the adjusted signal.

[0174] The coarse compensation module 30 is used to perform coarse frequency offset compensation on the local synchronization sequence within the maximum frequency offset range with a preset frequency offset compensation step size, so as to obtain multiple coarse compensation sequences, each coarse compensation sequence corresponding to a different frequency offset, and the length of each coarse compensation sequence is N.

[0175] The interception module 40 is used to obtain the minimum sampling point position based on the minimum time delay and the maximum sampling point position based on the maximum time delay. Starting from the minimum sampling point position, multiple sampling point positions are selected sequentially from the sampling point positions between the minimum and maximum sampling point positions according to a preset value interval, as each starting sampling point position. For each starting sampling point position, N consecutive signal values ​​are intercepted from the adjusted signal, starting from the starting sampling point position, to obtain the intercepted signal corresponding to the starting sampling point position.

[0176] The second determining module 50 is used to combine each coarse compensation sequence and the truncated signal corresponding to each starting sampling point position in pairs to form a number of sequence-signal combination pairs. The number of sequence-signal combination pairs is the product of the number of coarse compensation sequences and the number of starting sampling points. For each sequence-signal combination pair, based on the coarse compensation sequence and the truncated signal corresponding to the starting sampling point position of the sequence-signal combination pair, the relevant peak sequence of the sequence-signal combination pair is determined.

[0177] The third determining module 60 is used to determine the peak value and frequency offset estimate of each sequence-signal combination pair based on the correlation peak sequence of each sequence-signal combination pair.

[0178] The detection module 70 is used to detect the time-domain start position and frequency offset estimate of multiple users based on the burst decision threshold and the peak and frequency offset estimates of each sequence-signal combination pair.

[0179] The multi-user burst detection device of this invention reduces resource consumption by digitally adjusting the amplitude of the received signal to a suitable range; it first performs coarse frequency offset compensation on the local synchronization sequence and correlates it with the received signal, then groups and merges the correlation values, performs small-point FFT operation, finds the maximum correlation value, thereby reducing the impact of residual frequency offset on the correlation peak, ensuring signal recognition accuracy at low signal-to-noise ratio while reducing implementation complexity and resource consumption.

[0180] Another embodiment of the present invention provides a readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the steps of the multi-user burst detection method described in the above embodiments of the present invention.

[0181] Another embodiment of the present invention provides an electronic device, which includes a memory and a processor. The memory stores executable code. When the processor executes the executable code, it performs the steps of the multi-user burst detection method in the above embodiments of the present invention.

[0182] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0183] For ease of description, the above apparatus is described by dividing it into various functional units. Of course, in implementing this invention, the functions of each unit can be implemented in one or more software and / or hardware components.

[0184] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0185] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0186] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0187] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0188] In a typical configuration, an electronic device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0189] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0190] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by electronic devices. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0191] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0192] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0193] This invention can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This invention can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0194] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0195] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0196] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A multi-user burst detection method applied to a receiving end of a communication system, characterized in that, The method comprises: performing digital gain adjustment on the received signal to obtain an adjusted signal; determining a burst decision threshold based on the adjusted signal; performing coarse frequency offset compensation on the local synchronization sequence in a maximum frequency offset range with a preset frequency offset compensation step to obtain a plurality of coarse compensation sequences, each coarse compensation sequence corresponding to a different frequency offset, and each coarse compensation sequence having a length of N; obtaining a minimum sampling point position based on a minimum time delay and a maximum sampling point position based on a maximum time delay, selecting a plurality of sampling point positions from the minimum sampling point position and the maximum sampling point position at a preset interval as a plurality of starting sampling point positions; and for each starting sampling point position, taking N continuous signal values from the adjusted signal starting from the starting sampling point position to obtain a corresponding truncated signal; combining each coarse compensation sequence and the corresponding truncated signal of each starting sampling point position to form a plurality of sequence-signal combination pairs, the number of the sequence-signal combination pairs being the product of the number of coarse compensation sequences and the number of starting sampling point positions; and for each sequence-signal combination pair, determining a correlation peak sequence of the sequence-signal combination pair based on the coarse compensation sequence and the corresponding truncated signal of the starting sampling point position of the sequence-signal combination pair; determining a peak value and a frequency offset estimation value of each sequence-signal combination pair based on the correlation peak sequence of the sequence-signal combination pair; detecting the time domain starting position and the frequency offset estimation value of a plurality of users based on the burst decision threshold and the peak value and the frequency offset estimation value of each sequence-signal combination pair.

2. The multi-user burst detection method of claim 1, wherein, The method comprises: performing digital gain adjustment on the received signal to obtain an adjusted signal, specifically comprising: truncating K continuous signal values after a maximum time delay from the received signal to form a maximum time delay truncated signal; calculating an average signal power according to the maximum time delay truncated signal; obtaining a difference between a preset target power and the average signal power as a digital gain adjustment factor; 3. The multi-user burst detection method of claim 1, wherein, performing digital gain adjustment on the received signal based on the digital gain adjustment factor to obtain the adjusted signal. The method comprises: truncating N continuous signal values after a maximum time delay from the adjusted signal to form a noise power signal; calculating a power of the noise power signal to obtain a noise power; 4. The multi-user burst detection method of claim 1, wherein, multiplying the noise power and a preset noise threshold to obtain a burst decision threshold. For each sequence-signal combination pair, the correlation peak sequence of the sequence-signal combination pair is determined based on the coarse compensation sequence and the corresponding truncated signal of the starting sampling point position of the sequence-signal combination pair, specifically comprising: for each sequence-signal combination pair, the coarse compensation sequence of the sequence-signal combination pair is equally divided into a plurality of sub-sequences in a continuous order, the i-th sub-sequence being composed of the (i-1)×n+1-th to i×n-th elements of the coarse compensation sequence, where n is the length of the sub-sequence, i is a positive integer and i≤N / n. The truncated signal corresponding to the starting sampling point position of the sequence-signal combination pair is divided into a plurality of sub-signals in continuous order and equal length, and the i-th sub-signal is composed of the signal values from the (i-1)×n+1-th to the i×n-th of the truncated signal corresponding to the starting sampling point position of the sequence-signal combination pair; A correlation peak sequence of the sequence-signal combination pair is determined, wherein the length of the correlation peak sequence is N / n, and the i-th element of the correlation peak sequence is obtained by correlating the i-th sub-sequence of the coarse compensation sequence of the sequence-signal combination pair and the i-th sub-signal corresponding to the starting sampling point position of the sequence-signal combination pair.

5. The multiuser burst detection method of claim 1, wherein Based on the correlation peak sequence of each sequence-signal combination pair, a peak value and a frequency offset estimation value of the sequence-signal combination pair are determined, specifically including: The correlation peak sequence of each sequence-signal combination pair is converted from the time domain to the frequency domain to obtain a frequency domain correlation peak sequence of each sequence-signal combination pair; After a sub-carrier offset of the frequency domain correlation peak sequence of each sequence-signal combination pair, the frequency domain correlation peak sequence of each sequence-signal combination pair is added to the frequency domain correlation peak sequence of the sequence-signal combination pair to obtain a processed frequency domain correlation peak sequence of the sequence-signal combination pair; The peak value of the processed frequency domain correlation peak sequence of each sequence-signal combination pair and the interval between the position of the peak value and the center point are obtained; The interval between the position of the peak value of the processed frequency domain correlation peak sequence of each sequence-signal combination pair and the center point is compared with a preset threshold value, if the interval between the position of the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair and the center point is greater than the preset threshold value, the peak value of the sequence-signal combination pair is 0; if the interval between the position of the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair and the center point is less than or equal to the preset threshold value, the peak value of the sequence-signal combination pair is equal to the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair; The frequency offset estimation value of the sequence-signal combination pair is determined based on the interval between the position of the peak value of the processed frequency domain correlation peak sequence of each sequence-signal combination pair and the center point.

6. The multiuser burst detection method of claim 1, wherein Based on the burst decision threshold and the peak value and the frequency offset estimation value of each sequence-signal combination pair, the time domain starting position and the frequency offset estimation value of multiple users are detected, specifically including: For each of the peak values of each sequence-signal combination pair, the peak value of the sequence-signal combination pair is compared with the burst decision threshold; if the peak value of the sequence-signal combination pair is less than the burst decision threshold, the peak value of the sequence-signal combination pair is set to 0; if the peak value of the sequence-signal combination pair is greater than the burst decision threshold, the peak value of the sequence-signal combination pair remains unchanged; to obtain the decision peak value of each sequence-signal combination pair; The maximum value of the decision peak value of each sequence-signal combination pair is obtained as the maximum peak value; It is judged whether the maximum peak value is greater than 0; If not, no user is detected, and the detection ends; If yes, a user is detected, and the user is assigned a user index; the starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the time domain starting position of the user, and the frequency offset estimation value of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the frequency offset of the user. When a user is detected, the detected peak values of the sequence-signal combination pairs near the sequence-signal combination pair corresponding to the maximum peak value are set to 0, to obtain updated detected peak values of the sequence-signal combination pairs; and the maximum detected peak value of each sequence-signal combination pair is reacquired, and it is rejudged whether the maximum detected peak value is greater than 0 until the detection ends or the number of all the detected users reaches a preset number.

7. A multi-user burst detection apparatus applied to a receiving end of a communication system, characterized in that, The device comprises: a gain adjustment module configured to perform digital gain adjustment on the received signal to obtain an adjusted signal; a first determination module configured to determine a burst decision threshold based on the adjusted signal; a coarse compensation module configured to perform coarse frequency offset compensation on the local synchronization sequence in a maximum frequency offset range with a preset frequency offset compensation step to obtain a plurality of coarse compensation sequences, each coarse compensation sequence corresponding to a different frequency offset, and each coarse compensation sequence having a length of N; a clipping module configured to acquire a minimum sampling point position based on a minimum time delay and a maximum sampling point position based on a maximum time delay, select a plurality of sampling point positions from the sampling point positions between the minimum sampling point position and the maximum sampling point position at preset value intervals as a plurality of starting sampling point positions, and clip N continuous signal values from the adjusted signal starting from each starting sampling point position to obtain a clipping signal corresponding to the starting sampling point position; a second determination module configured to combine each coarse compensation sequence and the clipping signal corresponding to each starting sampling point position in pairs to form a plurality of sequence-signal combination pairs, the number of the sequence-signal combination pairs being a product of the number of the coarse compensation sequences and the number of the starting sampling point positions, and determine a correlation peak sequence of each sequence-signal combination pair based on the coarse compensation sequence and the clipping signal corresponding to the starting sampling point position of the sequence-signal combination pair; a third determination module configured to determine a peak value and a frequency offset estimation value of each sequence-signal combination pair based on the correlation peak sequence of the sequence-signal combination pair; a detection module configured to detect time domain starting positions and frequency offset estimation values of a plurality of users based on the burst decision threshold and the peak values and the frequency offset estimation values of the sequence-signal combination pairs.

8. The multiuser burst detection apparatus of claim 7, wherein, The digital gain adjustment on the received signal to obtain the adjusted signal specifically comprises: K continuous signal values after a maximum time delay are clipped from the received signal to form a maximum time delay clipping signal; an average signal power is calculated according to the maximum time delay clipping signal; a difference between a preset target power and the average signal power is obtained as a digital gain adjustment factor; the digital gain adjustment on the received signal is performed based on the digital gain adjustment factor to obtain the adjusted signal; the burst decision threshold is determined based on the adjusted signal, specifically comprising: N continuous signal values after a maximum time delay are clipped from the adjusted signal to form a noise power signal; a power of the noise power signal is calculated to obtain a noise power; the noise power and a preset noise threshold are multiplied to obtain the burst decision threshold.

9. The multiuser burst detection apparatus of claim 7, wherein, For each sequence-signal combination pair, based on the coarse compensation sequence of the sequence-signal combination pair and the intercepted signal corresponding to the starting sampling point position of the sequence-signal combination pair, a correlation peak sequence of the sequence-signal combination pair is determined, specifically including: For each sequence-signal combination pair, the coarse compensation sequence of the sequence-signal combination pair is divided into a plurality of sub-sequences in continuous order and with equal length, the i th sub-sequence is composed of the (i-1)×n+1 th to i×n th elements of the coarse compensation sequence, where n is the length of the sub-sequence, i is a positive integer and i≤N / n; The intercepted signal corresponding to the starting sampling point position of the sequence-signal combination pair is divided into a plurality of sub-signals in continuous order and with equal length, the i th sub-signal is composed of the (i-1)×n+1 th to i×n th signal values of the intercepted signal corresponding to the starting sampling point position; The correlation peak sequence of the sequence-signal combination pair is determined, wherein the length of the correlation peak sequence is N / n and the i th element of the correlation peak sequence is obtained by correlating the i th sub-sequence of the coarse compensation sequence of the sequence-signal combination pair and the i th sub-signal corresponding to the starting sampling point position of the sequence-signal combination pair; Based on the correlation peak sequence of each sequence-signal combination pair, the peak value and the frequency offset estimation value of the sequence-signal combination pair are determined, specifically including: The correlation peak sequence of each sequence-signal combination pair is converted from time domain to frequency domain to obtain the frequency domain correlation peak sequence of each sequence-signal combination pair; The frequency domain correlation peak sequence of each sequence-signal combination pair is offset by 1 sub-carrier and then added to the frequency domain correlation peak sequence of the sequence-signal combination pair to obtain the processed frequency domain correlation peak sequence of the sequence-signal combination pair; The peak value of the processed frequency domain correlation peak sequence of each sequence-signal combination pair and the interval between the position of the peak value and the center point are obtained; The interval between the position of the peak value of the processed frequency domain correlation peak sequence of each sequence-signal combination pair and the center point is compared with a preset threshold, if the interval between the position of the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair and the center point is greater than the preset threshold, the peak value of the sequence-signal combination pair is 0; if the interval between the position of the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair and the center point is less than or equal to the preset threshold, the peak value of the sequence-signal combination pair is equal to the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair; The frequency offset estimation value of each sequence-signal combination pair is determined based on the interval between the position of the peak value of the processed frequency domain correlation peak sequence of the sequence-signal combination pair and the center point.

10. The multiuser burst detection apparatus of claim 7, wherein, Based on the burst decision threshold and the peak value and the frequency offset estimation value of each sequence-signal combination pair, the time domain starting position and the frequency offset estimation value of multiple users are detected, specifically including: For each of the peak values of the sequence-signal combination pairs, the peak value of the sequence-signal combination pair is compared with a burst decision threshold; if the peak value of the sequence-signal combination pair is less than the burst decision threshold, the peak value of the sequence-signal combination pair is set to 0; if the peak value of the sequence-signal combination pair is greater than the burst decision threshold, the peak value of the sequence-signal combination pair remains unchanged; to obtain the decision peak values of the sequence-signal combination pairs; The maximum value of the decision peak values of the sequence-signal combination pairs is obtained as a maximum peak value; It is judged whether the maximum peak value is greater than 0; If not, no user is detected, and the detection ends; If yes, a user is detected, the user is assigned a user index; the starting sampling point position of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the time domain starting position of the user, and the frequency offset estimation value of the sequence-signal combination pair corresponding to the maximum peak value is obtained as the frequency offset of the user; When a user is detected, the decision peak values of the sequence-signal combination pairs near the sequence-signal combination pair corresponding to the maximum peak value are set to 0, to obtain the updated decision peak values of the sequence-signal combination pairs; and the updated maximum peak value of the decision peak values of the sequence-signal combination pairs is re-obtained, and it is re-judged whether the maximum peak value is greater than 0, until the detection ends or the number of all the detected users reaches a preset number.

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