Leading pattern recognition method, device and electronic equipment

Abstract

The present invention belongs to the field of wireless communication technology, and specifically relates to a method, device, and electronic device for identifying a preamble pattern. The method first receives a baseband sampling signal, and when it is determined that a valid signal has arrived, performs a cross-correlation calculation on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to a set time-frequency code; then, a delayed autocorrelation calculation is performed on the obtained cross-correlation calculation result and its energy value is calculated; if the maximum value of the energy value is greater than a preset peak threshold value, the preamble pattern corresponding to the set time-frequency code is determined to be the correct preamble pattern. The method only needs to perform a scanning process half the total number of time-frequency codes at most to find the correct preamble pattern, and has high recognition efficiency. Especially in the case of low signal-to-noise ratio and large frequency deviation, the method has high accuracy in time-frequency code detection and recognition, low delay overhead, and does not affect the speed at which the device joins the micro-network. It has low implementation complexity, low power consumption, and strong noise and frequency deviation resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a leading pattern recognition method, device and electronic equipment. Background Art

[0002] Ultra-Wide Band (UWB) based on MB-OFDM is a short-range wireless communication technology with the characteristics of low power consumption and high data transmission rate. Its maximum data transmission rate can reach 480Mbps. UWB is a wireless personal area network, so adjacent devices are combined into a network, which is called a piconet. In the MB-OFDM UWB system, channelization of different piconets is achieved by using different time-frequency codes (TFCs) for different piconets. Different time-frequency codes correspond to different preamble patterns. When a new device wants to join the current piconet, it needs to first detect the time-frequency code of the piconet, that is, identify and determine the preamble pattern used by the piconet.

[0003] MB-OFDM UWB systems, characterized by extremely short symbol intervals, high transmission rates (53.3 to 480 Mbps), frequency hopping, dense multipath channels, and a wide signal-to-noise ratio (SNR) range (-8.4 to 24 dB), place high demands on the speed and time required for signal processing at the receiver. Current recognition methods primarily rely on two algorithms: delayed autocorrelation (AC) of the received signal and cross-correlation (CC) between the received signal and the local preamble sequence. The AC algorithm has relatively low complexity but is significantly affected by noise, resulting in suboptimal performance under low SNR conditions and requiring further improvement in recognition accuracy. The CC algorithm offers strong noise immunity but is relatively complex and significantly affected by frequency offset. Furthermore, most of these methods focus on optimizing the implementation complexity or performance of a single function, failing to optimize the power consumption of the overall synchronization process. Furthermore, implementation complexity is a primary design consideration. Lower implementation complexity typically results in a certain degree of power reduction, but this does not necessarily translate to lower power consumption. For example, a key consideration for low-complexity methods is the hardware cost of operation. However, in low-power designs, it is necessary not only to reduce the hardware cost of the operation but also the number of operations performed. Therefore, to achieve low power consumption and efficient preamble recognition, the recognition algorithm must be simple, perform fewer operations, and be highly resistant to noise. Summary of the Invention

[0004] The object of the present invention is to provide a leading pattern recognition method, device and electronic device to solve the problem that the power consumption of the prior art method needs to be reduced and the recognition accuracy needs to be improved.

[0005] To solve the above technical problems, the present invention provides a leading pattern recognition method, comprising the following steps:

[0006] 1) Receive baseband sampling signals and determine whether valid signals have arrived;

[0007] 2) When it is determined that a valid signal has arrived, a cross-correlation calculation is performed on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to the set time-frequency code;

[0008] 3) performing delayed autocorrelation calculation on the cross-correlation calculation result obtained in step 2) and calculating its energy value;

[0009] 4) If the maximum value of the energy value is greater than the preset peak value threshold, it is determined that the preamble pattern corresponding to the set time-frequency code is the correct preamble pattern.

[0010] The present invention has the following beneficial effects: the present invention uses a cross-correlation-based matched filter to identify the correct preamble pattern. Specifically, when a valid signal is determined to have arrived, a cross-correlation calculation is performed on the symbol sequence corresponding to the baseband sampled signal and the local preamble sequence corresponding to the set time-frequency code. The cross-correlation calculation result is then subjected to a delayed autocorrelation calculation and its energy value is calculated. When the maximum energy value is greater than a preset peak threshold, the preamble pattern corresponding to the set time-frequency code is determined to be the correct preamble pattern. Otherwise, a cross-correlation calculation is performed on the symbol sequence corresponding to the baseband sampled signal and the local preamble sequence corresponding to another time-frequency code, and the above process is repeated. Since the total number of time-frequency codes is fixed, the correct preamble pattern can be found by performing a scan process at most half the total number of time-frequency codes, resulting in high recognition efficiency. Especially in low signal-to-noise ratio and large frequency offset conditions, the method achieves high accuracy in time-frequency code detection and recognition, does not affect the speed at which devices join the piconet, has low latency overhead, low implementation complexity, strong noise and frequency offset immunity, and low power consumption. Therefore, the method has high application value in MB-OFDM systems.

[0011] Furthermore, the cross-correlation calculation formula in step 2) is:

[0012]

[0013] Where s(n+i) is the symbol sequence corresponding to the baseband sampling signal, and r(n) is the received baseband sampling signal, n is the received sampling signal index, n=0,1,..., i is the correlation window data index, i=0,1,...,N-1, N is the correlation window length; c(i) is the local preamble sequence corresponding to the set time-frequency code, Q c (i) is the quantized value of the local preamble sequence c(i), Q c (i)=round(c(i)), round(·) means rounding; sign(·) means taking the sign function; |.| means taking the absolute value; F(n) is the result of cross-correlation calculation.

[0014] Furthermore, the energy value is calculated as follows:

[0015] E(n)=|F(n)·F * (nM·L)| 2

[0016] Where, E(n) is the calculated energy value; F(n) is the cross-correlation calculation result; F * (n) is the conjugate of F(n); L is the number of time domain points of a leading OFDM symbol; and M is the number of OFDM symbols in the interval.

[0017] Furthermore, in step 1), the signal power of the received baseband sampling signal is calculated, and whether a valid signal has arrived is determined based on the power change.

[0018] The beneficial effect is that whether a valid signal has arrived can be effectively and accurately identified by utilizing the power change situation.

[0019] Furthermore, the following method is used to determine whether a valid signal has arrived:

[0020] ① Compare the detected current power and the product of the previous power and the preset threshold: if the current power is greater than the product, the power increase value is increased by 1 and the previous power is updated; if the current power is less than or equal to the product, the power decrease value is increased by 1 and the previous power is updated;

[0021] When the power increase count value is greater than the preset power increase count threshold value, the power reduction count value is set to 0; when the power reduction count value is greater than the preset power reduction count threshold value, the power increase count value is set to 0; when the power reduction count value is less than or equal to the preset power reduction count threshold value and the power increase count value is greater than the preset power increase count threshold value, the power increase count value is increased by 1;

[0022] ② Repeat step ① and determine that a valid signal has arrived when the power increase times is equal to the preset signal detection threshold.

[0023] Furthermore, the update formula of the previous power is:

[0024] P_last(n)=P(n)*α+P_last(n-1)*(1-α)

[0025] Wherein, P_last(n) is the previous power after the update; P_last(n-1) is the previous power before the update; P(n) is the current power; α is the smoothing factor, 0<α≤1.

[0026] Furthermore, the power calculation formula is:

[0027]

[0028] Where P(n) is the calculated power; r(n) is the received baseband sampling signal, and n is the index of the received sampling signal, n = 0, 1, 2, ..., N p is the power calculation window length, k is the data index in the calculation window, k=0,1,...,N p -1.

[0029] Furthermore, when the time-frequency code is 1 or 2, M=3; when the time-frequency code is 3, 4, 5, 6 or 7, M=1; when the time-frequency code is 8, 9 or 10, M=2.

[0030] To solve the above technical problems, the present invention further provides a leading pattern recognition device, comprising a signal detection module, a correlation calculation module and a recognition module:

[0031] Signal detection module: used to receive baseband sampling signals and determine whether valid signals have arrived;

[0032] Correlation calculation module: used to perform cross-correlation calculation on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to the set time-frequency code when determining that a valid signal has arrived, and then perform delayed autocorrelation calculation on the cross-correlation calculation result and calculate its energy value;

[0033] Identification module: used to determine whether the maximum value of the energy value is greater than the preset peak threshold value, and if it is greater than, determine that the preamble mode corresponding to the set time-frequency code is the correct preamble mode.

[0034] The beneficial effect is that the above-mentioned identification device can ensure that the leading pattern recognition method operates effectively and reliably.

[0035] To solve the above technical problems, the present invention further provides an electronic device, comprising a memory and a processor, wherein the processor is configured to execute computer program instructions stored in the memory to implement the leader pattern recognition method introduced above.

[0036] The beneficial effect is that the electronic device can ensure that the leading pattern recognition method operates effectively and reliably. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of frequency band group allocation of the present invention;

[0038] Figure 2 It is a schematic diagram of the physical layer frame structure of the present invention;

[0039] Figure 3 It is a structural block diagram of a receiver system of the present invention;

[0040] Figure 4 is a flow chart of the leading pattern recognition method of the present invention;

[0041] Figure 5 is a block diagram of the leading pattern recognition scheme of the present invention;

[0042] Figure 6 It is a structural diagram of the leading pattern recognition device of the present invention. DETAILED DESCRIPTION

[0043] In an ultra-wideband system based on MB-OFDM, each transmitted OFDM symbol is frequency-hopped across different frequency bands depending on the time-frequency code used. Before synchronization is achieved, the receiver scans all frequency bands within the frequency band group, listening for possible preamble signals on a particular band. If no information data packet is detected within a certain period, the receiver switches to another frequency band to continue listening. Due to frequency hopping, only the symbols of the frequency band the receiver is currently monitoring will be detected for any incoming information data packet. For example, for TFC1, one symbol will be detected every three symbol periods. To determine the time-frequency code used for the current signal transmission, the most common method is to identify the preamble pattern of the frame signal. This can be achieved using a matched filter based on cross-correlation. If the received signal and the matched filter use the same preamble pattern, the calculated value will produce a peak, which can be used to determine the time-frequency code. Since there are a total of 10 time-frequency codes, the entire time-frequency code detection process requires a maximum of five scans, with each scan performing the same process. Based on this concept, the present invention can implement a preamble pattern recognition method, a preamble pattern recognition device, and an electronic device. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0044] Leading pattern recognition method embodiment:

[0045] The following ultra-wideband (UWB) system based on MB-OFDM uses a combination of OFDM modulation and frequency hopping technology for data transmission. Figure 1As shown. In this system, the spectrum bandwidth of 7.5GHz (3.1~10.6GHz) is divided into 14 frequency bands, and each frequency band has a bandwidth of 528MHz. The first 12 frequency bands are divided into 4 groups, each containing 3 frequency bands; the last 2 frequency bands form the fifth frequency band group (Band Group). In addition, 3 of the frequency bands are defined as the sixth frequency band group. According to the communication environment, the system can flexibly select one of the frequency band groups. In the MB-OFDM UWB system, a symbol contains N FFT = 128 IFFT samples and N ZPS =37 zero-padded suffixes. MB-OFDM UWB enables OFDM symbols to be time-frequency interleaved (TFI) transmitted on the frequency bands included in the frequency band group. During the duration of one OFDM symbol, only one frequency band is working. The system implements frequency hopping switching of frequency bands based on the time-frequency code (TFC). ECMA (European Computer Manufacturers Association) defines 10 time-frequency codes TFC1 to TFC10, and the preamble pattern corresponds to the time-frequency code. Using time-frequency codes to transmit data on different frequency bands can improve the system's frequency diversity gain and multiple access capabilities. For example, the TFC and preamble pattern of frequency band group #1 are shown in Table 1 below:

[0046] Table 1

[0047]

[0048] In the table above, the frequency band number corresponding to each TFC represents the frequency band number occupied by frequency-hopping transmission. Furthermore, different preamble sequences are used when the system uses different TFCs. ECMA-368 defines a unique 128-byte preamble sequence for each TFC.

[0049] The physical frame structure diagram defined by the MB-OFDM UWB system is as follows Figure 2 As shown in Figure 1, it consists of three parts: preamble, header, and payload data. The preamble precedes the header and primarily assists the receiver with time synchronization, carrier offset recovery, and channel estimation. The preamble is further composed of two parts: the packet / frame synchronization sequence and the channel estimation sequence. The time-frequency code or preamble pattern is primarily identified based on the packet / frame synchronization sequence.

[0050] The preamble pattern and time-frequency code play an important role in the symbol transmission of the UWB system based on MB-OFDM. Figure 3As shown. At the receiving end, if correct reception is to be achieved, the time-frequency code used by the transmitting end must be accurately understood. The present invention utilizes the characteristics of the preamble to propose a simple and efficient method for identifying and judging the preamble pattern. The overall process is as follows Figure 4 As shown, the specific process is as follows:

[0051] In step 1, the receiver receives a baseband sampling signal and performs a small-segment signal power calculation on the received baseband sampling signal.

[0052] Specifically:

[0053] The calculation is done as follows:

[0054]

[0055] Where P(n) is the calculated power; r(n) is the received baseband sampling signal; n is the index of the received sampling signal, n = 0, 1, 2, ...; k is the data index in the calculation window, k = 0, 1, ..., N p -1, N p is the power calculation window length. In this embodiment, N p =128.

[0056] Using the iterative calculation method to simplify, P(n) can be expressed as:

[0057]

[0058] Step 2: Determine the arrival of a valid signal based on the change in signal power. The signal of the MB-OFDMUWB system is a burst frame signal. Before the real signal arrives, the receiver digital-to-analog converter outputs a background noise signal. The background noise signal power is generally maintained at a low level. When a useful signal arrives, the received signal power will rise to a certain level. Therefore, a power threshold is preset. Within a certain detection time, if the signal power continues to exceed the preset threshold value and maintains for a certain period of time, it is determined that a valid signal has arrived. In addition, in order to prevent misjudgment caused by interference such as pulses or single tones, the signal power duration is counted. In this way, even if the signal power fluctuates momentarily due to interference, it will not affect the final judgment result. The specific process is as follows:

[0059] 1) Each time a sampling signal is received, if it is detected that the current power P(n) is greater than the product of the previous power P_last(n) and the preset threshold T1, where T1 can take a value range of (1.0, 2.5]), then go to step 2), otherwise go to step 3).

[0060] 2) The power increase times value pOnCnt is accumulated by 1. If the power increase times value pOnCnt is greater than the preset power increase times threshold value T on , where Ton If the value is 3, the power reduction times value pOffCnt is set to zero, and then go to step 4); otherwise, go directly to step 4).

[0061] 3) The power reduction times value pOffCnt is accumulated by 1. If the power reduction times value pOffCnt is greater than the preset power reduction times threshold value T off , where T off If the value is 2, the power increase times value pOnCnt is set to zero, and then go to step 4); if the power reduction times value pOffCnt is less than or equal to the preset power reduction times threshold value T off , and the power increase times value pOnCnt is greater than the preset power increase times threshold value T on , then the power increase times value pOnCnt is accumulated by 1, and then go to step 4); if the power reduction times value pOffCnt is less than or equal to the preset power reduction times threshold value T off , and the power increase times value pOnCnt is less than or equal to the preset power increase times threshold value T on , then go directly to step 4).

[0062] 4) Update the previous power value P_last(n), that is, P_last(n)=P(n)*α+P_last(n-1)*(1-α), where α is a smoothing factor, 0<α≤1.

[0063] 5) If the power increase times value pOnCnt is equal to the preset signal detection threshold value T Det , where T Det If the value is 120, it is determined that a valid signal has arrived.

[0064] Step 3: When it is determined that a valid signal has arrived, a cross-correlation calculation is performed on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to the set time-frequency code.

[0065] The formula for cross-correlation calculation is:

[0066]

[0067] Where s(n+i) is the calculated symbol sequence, and

[0068]

[0069] Where r(n) is the received baseband sampling signal, n is the received sampling signal index, n = 0, 1, ..., i is the correlation window data index, i = 0, 1, ..., N-1, N is the correlation window length, where N is N = 128; c(i) is the local preamble sequence corresponding to the set TFC, Q c(i) is the quantized value of the local preamble sequence c(i), Q c (i)=round(c(i)), where round(·) means rounding off; sign(·) means taking the sign function; and |.| means taking the absolute value.

[0070] Step 4: judge the cross-correlation results and identify the correct leading pattern.

[0071] 1) Perform delayed autocorrelation on F(n) obtained by cross-correlation calculation and calculate its energy value. The calculation formula is as follows:

[0072] E(n)=|F(n)·F * (nM·L)| 2 (5)

[0073] Where L is the number of time domain points of a leading OFDM symbol, which is L=165 here; M is the number of interval OFDM symbols, which is determined by TFC. In the MB-OFDM UWB system, when TFC=1 or 2, M is 3; when TFC=3, 4, 5, 6 or 7, M is 1; when TFC=8, 9 or 10, M is 2; F * (n) is the conjugate of F(n).

[0074] 2) Perform peak search based on energy value E(n) to obtain the maximum value E(n) max , if E is satisfied max ≥T2, then the preamble pattern corresponding to the set TFC is determined to be the correct preamble pattern. Wherein T2 is the preset peak threshold value, and the value of T2 here is 8.

[0075] like Figure 5As shown in the figure, the system is assumed to operate in frequency band group #1. If a valid signal is detected on frequency band 1, the radio is set to receive data fixedly on frequency band 1, and the TFC indexes or preamble pattern indices corresponding to correlators 1-3 are set to 1, 3, and 8, respectively, and four OFDM symbol periods are monitored. (This parameter refers to the duration of the detection. Theoretically, a setting of 3, the maximum OFDM symbol interval for each TFC, can be sufficient. However, to minimize the latency of the entire detection process, a value of 4 is preferred.) If a preamble pattern that meets the requirements is identified, the detection process is terminated and the corresponding TFC / preamble pattern index is output. If no preamble pattern is identified, the TFC indexes or preamble pattern indices corresponding to correlators 1-3 are then set to 2, 4, and 9, respectively, and monitoring continues for four OFDM symbol periods. If a preamble pattern that meets the requirements is identified, the detection process is terminated and the corresponding TFC / preamble pattern index is output. If no preamble pattern is identified, the TFC index or preamble pattern index corresponding to correlator 2 is set to 5, and two OFDM symbol periods are monitored. If the preamble pattern recognition conditions are met, the TFC index or preamble pattern index 5 is output. If no preamble pattern is still identified, the radio frequency is fixed to frequency band 2. Similarly, after receiving data and detecting the arrival of a signal, correlation identification of the preamble pattern is continued. That is, the TFC index or preamble pattern index corresponding to correlators 2 and 3 is set to 6 and 10 respectively, and three OFDM symbol periods are monitored. If a preamble pattern that meets the conditions is identified, the detection process is stopped and the corresponding TFC / preamble pattern index is output. If no preamble pattern is identified, the radio frequency is fixed to frequency band 3. After receiving data and detecting the arrival of a signal, correlation identification of preamble pattern 7 is continued. This completes all TFC / preamble pattern recognition.

[0076] In summary, the present invention performs cross-correlation calculation on the received signal and the matched filter, performs delayed autocorrelation calculation on the cross-correlation calculation result and determines its energy value. If the maximum value of the energy value is greater than the preset peak threshold value, it is determined that the preamble mode corresponding to the set TFC is the correct preamble mode. Since there are a total of 10 time-frequency codes, a maximum of 5 scanning processes are required to find the correct time-frequency code. The proposed preamble mode recognition method has low delay overhead, low implementation complexity, strong anti-noise and anti-frequency deviation capabilities, low power consumption, and has high application value in MB-OFDM systems.

[0077] Preamble pattern recognition device embodiment:

[0078] An embodiment of a leading pattern recognition device of the present invention is as follows: Figure 6 As shown, it includes a signal detection module, a correlation calculation module and an identification module (i.e. Figure 6The TFC identification module in the device can be applied to a server, a computer terminal or various mobile devices. The functions and effects to be achieved by each module are as follows:

[0079] Signal detection module: used to receive baseband sampling signals and determine whether valid signals have arrived;

[0080] Correlation calculation module: used to perform cross-correlation calculation on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to the set time-frequency code when determining that a valid signal has arrived, and then perform delayed autocorrelation calculation on the cross-correlation calculation result and calculate its energy value;

[0081] TFC identification module: used to determine whether the maximum value of the energy value is greater than the preset peak threshold value, and if it is, determine that the preamble mode corresponding to the set time-frequency code is the correct preamble mode.

[0082] Electronic device embodiment:

[0083] An electronic device embodiment of the present invention includes a memory, a processor, and an internal bus. The processor and the memory communicate and exchange data with each other via the internal bus. The processor executes a software program stored in the memory to implement a leading pattern recognition method described in an embodiment of the leading pattern recognition method of the present invention. The processor may be a processing device such as a microprocessor (MCU) or a programmable logic device (FPGA); and the memory may be any type of memory that uses electrical energy to store information, such as RAM or ROM, or may be other types of memory.

Claims

1. A leading pattern recognition method, characterized in that: The steps include: 1) Receive baseband sampling signals and determine whether valid signals have arrived; 2) When it is determined that a valid signal has arrived, a cross-correlation calculation is performed on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to the set time-frequency code; 3) Perform delayed autocorrelation calculation on the cross-correlation calculation result obtained in step 2) and calculate its energy value, and the energy value is: E(n)=|F(n)·F * (n-M·L)| 2 Where, E(n) is the calculated energy value; F(n) is the cross-correlation calculation result; F * (n) is the conjugate of F(n); L is the number of time domain points of a leading OFDM symbol; M is the number of OFDM symbols in the interval; 4) If the maximum value of the energy value is greater than the preset peak value threshold, it is determined that the preamble pattern corresponding to the set time-frequency code is the correct preamble pattern.

2. The leading pattern recognition method according to claim 1, wherein: The cross-correlation calculation formula in step 2) is: Where s(n+i) is the symbol sequence corresponding to the baseband sampling signal, and r(n) is the received baseband sampling signal, n is the received sampling signal index, n=0,1,..., i is the correlation window data index, i=0,1,...,N-1, N is the correlation window length; c(i) is the local preamble sequence corresponding to the set time-frequency code, Q c (i) is the quantized value of the local preamble sequence c(i), Q c (i)=round(c(i)), round(·) means rounding; sign(·) means taking the sign function; |.| means taking the absolute value; F(n) is the result of cross-correlation calculation.

3. The leading pattern recognition method according to claim 1, wherein: In step 1), the signal power of the received baseband sampling signal is calculated, and whether a valid signal has arrived is determined based on the power change.

4. The leading pattern recognition method according to claim 3, wherein: Use the following method to determine whether a valid signal has arrived: ① Compare the detected current power and the product of the previous power and the preset threshold: if the current power is greater than the product, the power increase value is increased by 1 and the previous power is updated; if the current power is less than or equal to the product, the power decrease value is increased by 1 and the previous power is updated; When the power increase count value is greater than the preset power increase count threshold value, the power reduction count value is set to 0; when the power reduction count value is greater than the preset power reduction count threshold value, the power increase count value is set to 0; when the power reduction count value is less than or equal to the preset power reduction count threshold value and the power increase count value is greater than the preset power increase count threshold value, the power increase count value is increased by 1; ② Repeat step ① and determine that a valid signal has arrived when the power increase times is equal to the preset signal detection threshold.

5. The leading pattern recognition method according to claim 4, characterized in that: The update formula for the previous power is: P_last(n)=P(n)*α+P_last(n-1)*(1-α) Wherein, P_last(n) is the previous power after the update; P_last(n-1) is the previous power before the update; P(n) is the current power; α is the smoothing factor, 0<α≤1.

6. The leading pattern recognition method according to claim 3 or 4, characterized in that: The power calculation formula is: Where P(n) is the calculated power; r(n) is the received baseband sampling signal, and n is the index of the received sampling signal, n = 0, 1, 2, ..., N p is the power calculation window length, k is the data index in the calculation window, k=0,1,...,N p -1.

7. The leading pattern recognition method according to claim 1, characterized in that: When the time-frequency code is 1 or 2, M=3; when the time-frequency code is 3, 4, 5, 6 or 7, M=1; when the time-frequency code is 8, 9 or 10, M=2.

8. A leading pattern recognition device, characterized in that: Including signal detection module, correlation calculation module and recognition module: Signal detection module: used to receive baseband sampling signals and determine whether valid signals have arrived; Correlation calculation module: used to perform cross-correlation calculation on the symbol sequence corresponding to the baseband sampling signal and the local preamble sequence corresponding to the set time-frequency code when determining that a valid signal has arrived, and then perform delayed autocorrelation calculation on the cross-correlation calculation result and calculate its energy value. The energy value is: E(n)=|F(n)·F * (n-M·L)| 2 Where, E(n) is the calculated energy value; F(n) is the cross-correlation calculation result; F * (n) is the conjugate of F(n); L is the number of time domain points of a leading OFDM symbol; M is the number of OFDM symbols in the interval; Identification module: used to determine whether the maximum value of the energy value is greater than the preset peak threshold value, and if it is greater than, determine that the preamble mode corresponding to the set time-frequency code is the correct preamble mode.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the processor is configured to execute computer program instructions stored in the memory to implement the leader pattern recognition method according to any one of claims 1 to 7.

Images