Wireless local area network terminal time domain wake-up method, system, device and storage medium

Abstract

The application discloses a wireless local area network terminal time domain wake-up method, system, device and storage medium, and belongs to the technical field of wireless communication. The method comprises the following steps: an access point (AP) allocates a unique cyclic prefix (CP) length to each wireless terminal, and establishes a mapping table of the CP length and the wireless terminal; when a wake-up signal is sent, the AP adds a CP with a corresponding length to a selected OFDM short training sequence according to the CP length of a target wireless terminal; when the wireless terminal is in a silent state, only a front-end radio frequency part is used to collect air interface wireless time domain signals, window sliding calculation is performed on the collected wireless time domain signals, and a symbol synchronization point is judged through a Schmidl algorithm; the wireless terminal counts the number of continuous symbol synchronization points, obtains the CP length, compares the CP length with the CP length allocated by the wireless terminal, and if the CP lengths are equal, the wireless terminal exits the silent state and is woken up. The application can realize fast wake-up while keeping low power consumption, and avoids additional hardware.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wireless communication, and particularly relates to a wireless local area network terminal time domain wake-up method, system, device and storage medium. BACKGROUND

[0002] In today's era, communication technology continues to develop rapidly, and users' requirements for network use experience are increasing, and faster speed and more stable performance have become an inevitable trend. Under this background, as a key technology to meet user needs, the standard and performance of wireless local area network (WLAN) are constantly evolving and improving.

[0003] In the key period of transformation and upgrading from traditional systems to new power systems in the power industry, wireless local area network communication technology is increasingly widely used in power scenarios such as substations, converter stations, and transmission lines. As the scale of terminals using wireless local area network transmission in power scenarios continues to expand, the types of sensors are also increasingly diverse. Under normal circumstances, sensor data will be reported periodically, and during non-transmission periods, terminal devices will remain in a silent state to reduce power consumption. However, in the silent state, terminal devices cannot respond to business needs triggered by key events in a timely manner. In order to balance the low power consumption needs of data acquisition terminals and the real-time response of burst business needs for key events, there is an urgent need for a fast and effective real-time terminal wake-up technology to solve the conflict between low power consumption needs and high real-time needs of acquisition terminals. Early wireless local area networks usually lack dedicated wake-up technology and mainly rely on periodic listening of beacon frames at the physical layer to achieve wake-up. While new wireless local area network technologies (such as WiFi6, WiFi7) use trigger frames to achieve terminal wake-up, combined with MAC layer-based wake-up technology and application layer-based wake-up technology (such as timed wake-up, message push triggering, etc.) to control terminal activation, but these methods require detection and frequency domain decoding of air interface wireless signals, which to some extent increases terminal power consumption and affects the use time of a large number of low-power devices, and cannot meet the strict requirements of low power consumption and real-time performance in power scenarios. SUMMARY

[0004] The purpose of the present application is to provide a wireless local area network terminal time domain wake-up method, system, device and storage medium to avoid additional hardware, simplify protocol processing, and achieve fast wake-up while maintaining low power consumption.

[0005] In order to achieve the above-mentioned purpose, the present application has the following technical solutions:

[0006] In a first aspect, a wireless local area network terminal time domain wake-up method includes:

[0007] The access point (AP) assigns a unique cyclic prefix (CP) length to each wireless terminal and establishes a mapping table of the cyclic prefix (CP) length and the wireless terminal;

[0008] Based on the mapping table of the cyclic prefix (CP) length and the wireless terminal, when sending the wake-up signal, the access point (AP) adds a cyclic prefix (CP) of a corresponding length to the selected orthogonal frequency division multiplexing (OFDM) short training sequence according to the cyclic prefix (CP) length of the target wireless terminal;

[0009] Based on the orthogonal frequency division multiplexing (OFDM) short training sequence with the added cyclic prefix (CP) of the corresponding length, when the wireless terminal is in a silent state, only the front-end radio frequency part is used to collect the air interface wireless time domain signal, and the collected wireless time domain signal is subjected to window sliding calculation to determine the symbol synchronization point through the Schmidl algorithm.

[0010] The wireless terminal counts the number of consecutive symbol synchronization points to obtain the cyclic prefix (CP) length, and compares the cyclic prefix (CP) length with the cyclic prefix (CP) length assigned to the wireless terminal itself. If they are equal, the corresponding wireless terminal exits the silent state and is woken up.

[0011] As a preferred scheme, in the step of assigning a unique cyclic prefix (CP) length to each wireless terminal by the access point (AP), each wireless terminal periodically reports service data to the access point (AP), and the access point (AP) assigns a unique cyclic prefix (CP) length to the corresponding wireless terminal according to the identification of the wireless terminal and the wake-up allocation scheme of the cyclic prefix (CP) length after receiving the service data periodically reported by the wireless terminal.

[0012] When the access point (AP) issues an instruction to wake up the cyclic prefix (CP) length to the wireless terminal, the wireless terminal sets the symbol synchronization parameter after receiving the instruction to wake up the cyclic prefix (CP) length.

[0013] The access point (AP) issues a wake-up time domain signal based on the cyclic prefix (CP) before the next periodic reporting of service data by the wireless terminal, and the wake-up time domain signal based on the cyclic prefix (CP) only contains one orthogonal frequency division multiplexing (OFDM) short training sequence data.

[0014] As a preferred scheme, the selected orthogonal frequency division multiplexing (OFDM) short training sequence carries non-zero value data on even subcarriers in the frequency domain, and the odd subcarriers carry zero data.

[0015] Inverse Fourier transform is performed on the orthogonal frequency division multiplexing (OFDM) short training sequence to form an orthogonal frequency division multiplexing (OFDM) time domain signal, and the orthogonal frequency division multiplexing (OFDM) time domain signal has the characteristic of symmetry between the first half and the second half.

[0016] According to the cyclic prefix (CP) length of the target wireless terminal to be woken up, a corresponding cyclic prefix (CP) length is added to the orthogonal frequency division multiplexing (OFDM) time domain signal.

[0017] As a preferred solution, when the wireless terminal is in a silent state and only the front-end radio frequency part collects the air interface wireless time domain signal, a data segment with a length of the Fourier transform point number is selected from the starting point.

[0018]

[0019]

[0020]

[0021] In the formula, is the autocorrelation value of the received data before and after, is the conjugate data value of the received data, is the position of the calculation sequence starting point in the received sequence, is the count value, is the received data value, is the Fourier transform series, is the received data power spectral density; is the M value of the starting point of the received data;

[0022] The calculated M value is compared with the set threshold value, and if the M value is greater than the threshold value, counting begins;

[0023] The M value at the next moment is continuously calculated, and if the M value at the next moment is also greater than the set threshold value, counting continues, and the process of M value calculation and comparison with the threshold value is continuously looped until the M value is less than the threshold value, at which point the process stops;

[0024] The counting result is counted and compared with the cyclic prefix (CP) length allocated by the wireless terminal itself, and if the counting result is equal to the cyclic prefix (CP) length allocated by the wireless terminal itself, the wireless terminal exits the silent state and begins data reporting transmission; if the counting result is not equal to the cyclic prefix (CP) length allocated by the wireless terminal itself, the wireless terminal continues to remain in the silent state until the time for the wireless terminal to periodically report service data to the access point (AP) arrives.

[0025] As a preferred solution, the cyclic prefix (CP) length and the mapping table of the wireless terminal each group of mapping data contains a mapping starting time;

[0026] When the access point (AP) assigns a unique cyclic prefix (CP) length to each wireless terminal, for a newly accessed wireless terminal, it is determined whether to assign a cyclic prefix (CP) length, if no cyclic prefix (CP) length is assigned, a mapping table is searched, a first cyclic prefix (CP) length position not assigned to a wireless terminal is found, and is assigned to the corresponding wireless terminal; if no unassigned cyclic prefix (CP) length position is found, the longest cyclic prefix (CP) length is increased by 1, the mapping table length is increased, and is used as a new cyclic prefix (CP) length position;

[0027] For a wireless terminal to which a cyclic prefix (CP) length has been assigned, the mapping start time is updated to the current time;

[0028] The mapping table is periodically checked for the difference between the current time and the start time of a wireless terminal, and when the difference is greater than a specified time, the mapping relationship of the corresponding wireless terminal is deleted.

[0029] In a second aspect, a wireless local area network terminal time domain wake-up system is provided, comprising:

[0030] A cyclic prefix (CP) length assignment module is configured to assign a unique cyclic prefix (CP) length to each wireless terminal at an access point (AP), and to establish a mapping table of cyclic prefix (CP) length and wireless terminal;

[0031] A short training sequence cyclic prefix (CP) increase module is configured to, based on the mapping table of cyclic prefix (CP) length and wireless terminal, when a wake-up signal is sent, the access point (AP) adds a cyclic prefix (CP) of a corresponding length to a selected orthogonal frequency division multiplexing (OFDM) short training sequence according to the cyclic prefix (CP) length of a target wireless terminal;

[0032] A symbol synchronization point determination module is configured to, based on the orthogonal frequency division multiplexing (OFDM) short training sequence with the added cyclic prefix (CP) of a corresponding length, when a wireless terminal is in a silent state, only collect air interface wireless time domain signals through a front-end radio frequency part, perform window sliding calculation on the collected wireless time domain signals, and determine a symbol synchronization point through the Schmidl algorithm;

[0033] A cyclic prefix (CP) length comparison wake-up module is configured to have a wireless terminal count the number of consecutive symbol synchronization points, obtain a cyclic prefix (CP) length, and compare the cyclic prefix (CP) length with the cyclic prefix (CP) length assigned to the wireless terminal itself, and if they are equal, the corresponding wireless terminal exits the silent state and is woken up.

[0034] As a preferred solution, the cyclic prefix CP length allocation module allocates a unique cyclic prefix CP length to each wireless terminal when the access point AP receives the periodically reported service data from each wireless terminal, and the access point AP allocates a unique cyclic prefix CP length to the corresponding wireless terminal according to the identification of the wireless terminal and the wake-up allocation scheme of the cyclic prefix CP length after receiving the periodically reported service data from the wireless terminal.

[0035] When the access point AP issues the instruction of the wake-up cyclic prefix CP length to the wireless terminal, the wireless terminal sets the symbol synchronization parameter after receiving the instruction of the wake-up cyclic prefix CP length.

[0036] The access point AP issues the cyclic prefix CP-based wake-up time domain signal when the access point AP needs to temporarily collect data before the next periodic reporting of the service data by the wireless terminal, and the cyclic prefix CP-based wake-up time domain signal only contains one orthogonal frequency division multiplexing OFDM short training sequence data.

[0037] As a preferred solution, the short training sequence cyclic prefix CP increasing module increases the cyclic prefix CP of the selected orthogonal frequency division multiplexing OFDM short training sequence by a corresponding length, and the selected orthogonal frequency division multiplexing OFDM short training sequence carries non-zero value data on even subcarriers in the frequency domain, and the odd subcarriers carry zero data.

[0038] The short training sequence cyclic prefix CP increasing module performs inverse Fourier transform on the orthogonal frequency division multiplexing OFDM short training sequence to form an orthogonal frequency division multiplexing OFDM time domain signal, and the orthogonal frequency division multiplexing OFDM time domain signal has the characteristic of symmetry between the first half and the second half.

[0039] The orthogonal frequency division multiplexing OFDM time domain signal is increased by a corresponding set cyclic prefix CP length according to the cyclic prefix CP length of the target wireless terminal to be woken up.

[0040] As a preferred solution, the symbol synchronization point judgment module selects a data segment with a Fourier transform point number from the starting point when the wireless terminal is in a silent state and only collects air interface wireless time domain signals through the front-end radio frequency part. The Schmidl algorithm uses the following expression to calculate the M value of the starting point:

[0041]

[0042]

[0043]

[0044] In the formula, is the autocorrelation value before and after receiving the data. a conjugate data value of the received data, a position of a start point of the sequence in the received sequence, a count value, a received data value, a Fourier transform series, a received data power spectral density; an M value of a start point of the received data;

[0045] The cyclic prefix CP length comparison wake-up module compares the calculated M value with a set threshold value, and if the M value is greater than the threshold value, counting is started;

[0046] The M value of the next moment is continuously calculated, and if the M value of the next moment is also greater than the set threshold value, counting is continuously performed. The process of calculating the M value and comparing with the threshold value is continuously performed in a loop until the M value is less than the threshold value, at which point the process is stopped;

[0047] The counting result is counted and compared with the cyclic prefix CP length of the wireless terminal itself, and if the counting result is equal to the cyclic prefix CP length of the wireless terminal itself, the wireless terminal exits the silent state and starts data reporting transmission. If the counting result is not equal to the cyclic prefix CP length of the wireless terminal itself, the wireless terminal continues to maintain the silent state until the time for the wireless terminal to periodically report service data to the access point AP arrives.

[0048] As a preferred scheme, the cyclic prefix CP length allocation module establishes a mapping table of the cyclic prefix CP length and the wireless terminal, and each set of mapping data in the mapping table contains a mapping start time;

[0049] When the access point AP allocates a unique cyclic prefix CP length to each wireless terminal, for a newly accessed wireless terminal, it is determined whether to allocate a cyclic prefix CP length. If no cyclic prefix CP length is allocated, the mapping table is searched to find the first cyclic prefix CP length position that is not allocated to a wireless terminal, and is allocated to the corresponding wireless terminal. If no unallocated cyclic prefix CP length position is found, the longest cyclic prefix CP length is increased by 1, and the mapping table length is increased as a new cyclic prefix CP length position;

[0050] For a wireless terminal that has been allocated a cyclic prefix CP length, the mapping start time is updated to the current time;

[0051] The difference between the current time and the start time of the wireless terminal in the mapping table is periodically checked, and when the difference is greater than a specified time, the mapping relationship of the corresponding wireless terminal is deleted.

[0052] In a third aspect, an electronic device is provided, comprising a processor and a memory, the processor being configured to execute a computer program stored in the memory to implement the time-domain wake-up method of the WLAN terminal as described in the first aspect.

[0053] In a fourth aspect, a computer-readable storage medium is provided, the computer-readable storage medium storing at least one instruction, the at least one instruction being configured to implement the time-domain wake-up method of the WLAN terminal as described in the first aspect when executed by a processor.

[0054] Compared with the prior art, the first aspect of the present application has at least the following beneficial effects:

[0055] The existing physical layer-based wake-up technology needs to configure a separate hardware detection device, increasing hardware cost and integration complexity, and there is a clock synchronization problem with the main system. The wake-up technology based on the media access control (MAC) layer requires the terminal to periodically listen to the MAC layer signaling in the sleep state, increasing the protocol overhead and computational overhead, resulting in high energy consumption. For a large number of Internet of Things detection devices deployed in the power scene, both low power consumption and fast response to sudden business needs are required, and the existing technology cannot meet both needs at the same time. The root cause of these problems is that the existing technology either relies on additional hardware or relies on complex protocols, and cannot achieve fast wake-up while maintaining low power consumption. The time-domain wake-up method of the WLAN terminal proposed by the present application utilizes the cyclic prefix (CP) characteristics of the orthogonal frequency division multiplexing (OFDM) signal, encodes the wake-up information by adjusting the CP length, and does not require additional hardware. The wireless terminal only needs to turn on the front-end radio frequency part for simple symbol synchronization detection, without complex protocol processing, reducing power consumption. The CP length is one-to-one mapped with the wireless terminal, achieving accurate wake-up of specific wireless terminals. Wake-up judgment is based on the characteristics of the physical layer signal, and the response speed is fast, which can meet the sudden business needs. The CP length mapping table is dynamically allocated and updated to adapt to network changes, improving flexibility. In this way, additional hardware is avoided and protocol processing is simplified, achieving fast wake-up while maintaining low power consumption. The wake-up decision in the method of the present application is only in the time domain and does not involve symbol demodulation, which can greatly reduce the power consumption of the terminal in the silent state. In the paging process, the paging content does not include the characteristics of the specific wireless terminal, which also improves the security.

[0056] It can be understood that the beneficial effects of the second aspect to the fourth aspect described above can be referred to the related description in the first aspect described above, and will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0058] Figure 1 The wireless local area network terminal time domain wake-up method flow chart of the embodiment of the present application;

[0059] Figure 2 The wireless terminal and access point AP communication schematic diagram of the embodiment of the present application;

[0060] Figure 3 The cyclic prefix CP length allocation schematic diagram of the wireless terminal of the embodiment of the present application;

[0061] Figure 4 The wireless local area network terminal time domain wake-up system structure schematic diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0062] In the following description, specific details are set forth in order to provide a thorough understanding of embodiments of the present application. However, persons of ordinary skill in the art will readily recognize that embodiments of the present application can be practiced without these specific details. In other instances, well-known structures, devices, circuits, and processes have not been described in detail so as not to unnecessarily obscure the description of the present application.

[0063] Prior art one

[0064] The wake-up receiver (WUR) is a kind of ultra-low power physical layer components, which works independently of the traditional Wi-Fi transceiver. Its core functions are as follows: continuously monitor the wake-up signal of a specific frequency, and trigger the main system to wake up from the sleep state when the target signal is detected. During the main system wake-up period, WUR remains silent and does not participate in data transmission. Usually, WUR uses a specific sequence (such as Manchester encoding) for wireless signal transmission. It uses a third-party hardware acquisition device (radio frequency RF front end) to receive wireless signals, uses an envelope detector to extract the signal envelope, and uses a digital correlator to match the preset specific sequence. If the detection result exceeds the threshold, the wake-up circuit is triggered. The specific implementation method includes: frequency hopping wake-up, sending a wake-up signal at a specific frequency channel. Phase encoding, using signal phase change to carry wake-up instructions.

[0065] The WUR wake-up frame contains the following parts:

[0066] Preamble: 7~10 bytes, used for synchronization and detection.

[0067] Address: 4~8 bytes, identifies the target device.

[0068] Control: 2 bytes, indicates the type of wake-up (e.g. normal wake-up, emergency wake-up).

[0069] CRC Check: 2 bytes, ensures the integrity of the frame.

[0070] The key technical indicators of WUR include the following aspects:

[0071] Wake-up sensitivity: refers to the minimum detectable signal strength, usually <-70dBm.

[0072] Wake-up delay: the time from signal detection to the main system wake-up, typical value <1ms.

[0073] False wake-up rate: the probability of wake-up triggered by non-target signals, requirement <0.1%.

[0074] Missed wake-up rate: the probability of not triggering wake-up by target signals, requirement <0.01%.

[0075] The physical layer WUR technology realizes ultra-fast wake-up under ultra-low power consumption conditions through dedicated hardware design, providing an ideal solution for long-term standby and real-time response of Internet of Things devices. With the advancement of technology and the improvement of integration, WUR will become a standard component of future wireless communication, driving deep changes in smart home, medical health and other fields.

[0076] However, there are some problems in the prior art. The use of the prior art for terminal wake-up requires independent configuration of a set of hardware detection devices, which increases hardware costs; if integrated with the main device, the integration complexity will be greatly increased, and there is a problem of clock synchronization between WUR and the main system; due to the inconsistency of the wake-up frequency and the main device frequency, the attenuation of over-the-air transmission is abnormal, so there may be problems such as inability to wake up or the main device unable to work normally after wake-up.

[0077] Prior art two

[0078] The MAC layer (Medium Access Control Layer) is located in the data link layer and is responsible for coordinating the terminal's access to the wireless channel. The core goal of the MAC layer wake-up technology is to achieve "on-demand wake-up" of the terminal through software protocol optimization without increasing hardware complexity, balancing power consumption, wake-up delay, and real-time requirements. Compared with the physical layer WUR (Wake-Up Receiver) technology, the MAC layer scheme does not require special hardware and has better compatibility. However, due to the dependence on upper-layer protocol monitoring, it needs to perform demodulation and decoding on the data, so the power consumption is usually higher.

[0079] In a wireless local area network (such as WiFi), the access point (AP) periodically sends Beacon frames (usually with an interval of 100ms-500ms), which contain network status, timing information, etc. The terminal determines whether there is data to be received by listening to the Beacon frame, and if there is, it wakes up, and if not, it continues to sleep. The advantage of this method is that it is simple to implement and has strong compatibility, and is suitable for scenarios with high real-time requirements (such as industrial control).

[0080] The Trigger frame wake-up technology adopted in WiFi 6 and subsequent versions: the AP actively sends a Trigger frame to explicitly instruct the target terminal to wake up and prepare to receive data, avoiding continuous listening by the terminal. This technology is further optimized in IEEE 802.11be (WiFi7) to support multi-user MIMO wake-up, improving efficiency. The specific process is as follows: the terminal enters a sleep state, only keeping the MAC layer module running at low power; when data needs to be sent to the terminal, a Trigger frame carrying the terminal's identifier is sent; the terminal MAC layer wakes up after parsing the Trigger frame and establishes a data connection.

[0081] Table 1 MAC layer wake-up technology parameters

[0082]

[0083] The existing MAC layer wake-up technology mainly uses protocols for wake-up. In the process of handling, the terminal needs to wake up regularly for listening even if there is no data transmission. Continuous listening will lead to high energy consumption. The MAC layer wake-up technology usually requires the terminal to periodically listen to the MAC layer signaling (such as Beacon frame, Trigger frame, etc.) in the sleep state to detect whether there is a wake-up instruction. Although the listening period can be optimized, frequent channel detection and signaling analysis will still consume a certain amount of power. In addition, air interface signaling processing will increase additional power consumption. When there are a large number of terminals in the network, the MAC layer needs to process more wake-up signaling, and the terminal needs to continuously analyze these signaling to confirm whether it is woken up. Moreover, multi-terminal competition will cause wake-up delay. When the MAC layer adopts a contention access method (such as CSMA / CA, Carrier Sense Multiple Access / Collision Avoidance), multiple terminals may simultaneously compete for channel resources, which can cause wake-up signaling transmission failure or delay. In addition, the protocol implementation complexity is high. The MAC layer wake-up technology needs to be deeply coupled with the MAC layer mechanism of specific network protocols such as WiFi, ZigBee, LoRaWAN (Long Range Wide Area Network), etc. The wake-up logic of different protocols is quite different.

[0084] The present application is based on the technical characteristics of the autonomous controllable power wireless local area network. According to the self-defined waveform customization, the terminal wake-up is realized at the physical layer, and the wake-up function in the wireless local area network terminal area is realized by using the mapping relationship between the identifier and the terminal dynamics. The cost and other problems caused by the need to redeploy external hardware devices in the existing physical layer wake-up technology are solved, and the additional protocol overhead and operation overhead required for terminal wake-up at the MAC layer are reduced. The fast effectiveness based on the physical layer wake-up technology is maintained, and the protocol customization and operation overhead required for the terminal wake-up technology based on the MAC layer are reduced.

[0085] The wireless local area network adopts a burst access technology system, and the wireless communication wake-up function is an essential technology for wireless local area network technology. In the power business scenario, there are a large number of Internet of Things detection devices, and more and more detection devices use the wireless local area network mode for data transmission. Under normal circumstances, the collected data is periodically reported to the system by the terminal device, such as 15 minutes of collection. When there is no data transmission, the terminal device is in a silent state and does not emit a power signal to save the power consumption of the device. When real-time data is needed, the terminal needs to be woken up and required to perform real-time data transmission.

[0086] As can be seen from the defects of the prior art, the wake-up technology based on the physical layer needs to customize special hardware devices for wireless signal collection and analysis. The increase of these devices will cause an increase in cost and maintenance complexity, and there is a problem of coordination between the wake-up device and the business device.

[0087] From the defects of the prior art two, the MAC-based wake-up technology needs to customize a special protocol for terminal wake-up, and in the implementation process, wireless signals need to be collected and coded. These protocol processing and coding processing increase the operation complexity, and put high requirements on the power of the Internet of Things terminal, and greatly increase the complexity of the wake-up terminal protocol.

[0088] In the power scenarios such as substations and converter stations, in order to realize fine-grained data collection, more and more data collection devices represented by Internet of Things sensors are deployed. These devices have the characteristics of small size, low power consumption, strong environmental adaptability and wide deployment. These characteristics make the device reduce the power consumption as much as possible under the condition of meeting the business data collection, data storage and data backhaul. This requires the data collection device to collect data and transmit data through the wireless module on the collection device in the working condition, at this time, it is in full load operation state, and the power consumption is large; in the non-working condition of the device, it is in low power consumption or deep sleep state, and the power consumption in the non-working state of the device is greatly reduced, thereby reducing the overall power consumption of the data collection device. When the data collection device enters the low power consumption or deep sleep state, it can realize active business reporting according to the set conditions, but cannot realize the business demand of rapid response when a key event is triggered. In order to ensure the low system power consumption of the data collection terminal and realize the sudden business demand of the key event, a wireless air interface wake-up technology is usually used to make the data collection device jump from the deep sleep state to the normal working state. The wireless air interface wake-up technology makes the device in deep sleep state most of the time, and only wakes up quickly when a specific wireless signal is received, and enters the working state, so that the overall energy consumption of the device in long time working can be reduced. As the core mechanism connecting sleep energy saving and instant response, the wireless wake-up function is one of the very important indicators reflecting the reliability of the Internet of Things collection device, which solves the core contradiction of the Internet of Things - the conflict between low power consumption demand and high real-time demand, and enables large-scale devices to run stably for a long time and respond in real time at critical moments.

[0089] Based on the application in the power scenario, the present application proposes a technical solution for determining the burst pulse symbol synchronization platform width by algorithm based on the transformed cyclic prefix, and implementing wake-up on the target terminal. The present application can solve the problem of increasing cost and maintenance complexity caused by the need to customize special hardware devices in the wake-up technology based on the physical layer in the prior art one, and can avoid the problem of cooperation between the wake-up device and the business device. At the same time, the present application solves the problem of customizing a special protocol for terminal wake-up in the MAC-based wake-up technology in the prior art two, avoids the need to collect and code wireless signals in the implementation process, thereby reducing the operation complexity, and reducing the power consumption requirement of the Internet of Things terminal in the prior art two.

[0090] Referring to Figure 1 The wireless LAN terminal time domain wake-up method of the embodiment of the present application mainly comprises the following steps:

[0091] The access point AP allocates a unique cyclic prefix CP length to each wireless terminal and establishes a mapping table of cyclic prefix CP length and wireless terminal;

[0092] Based on the mapping table of cyclic prefix CP length and wireless terminal, when sending a wake-up signal, the access point AP adds a cyclic prefix CP of corresponding length to the selected orthogonal frequency division multiplexing OFDM short training sequence according to the cyclic prefix CP length of the target wireless terminal;

[0093] Based on the orthogonal frequency division multiplexing OFDM short training sequence with the added cyclic prefix CP of corresponding length, when the wireless terminal is in a silent state, only the front-end radio frequency part is used to collect air interface wireless time domain signals, the collected wireless time domain signals are calculated through window sliding, and the symbol synchronization point is determined through the Schmidl algorithm.

[0094] The wireless terminal counts the number of continuous symbol synchronization points to obtain the cyclic prefix CP length, and compares the cyclic prefix CP length with the cyclic prefix CP length allocated to the wireless terminal itself. If they are equal, the corresponding wireless terminal exits the silent state and is woken up.

[0095] The wireless LAN uses the orthogonal frequency division multiplexing (OFDM) modulation technology. In order to effectively solve the problem of inter-symbol interference and interference between subcarriers, the cyclic prefix (CP) is usually used to suppress interference. The cyclic prefix is used to reduce or eliminate the inter-symbol interference caused by multipath propagation. The length of the CP is related to the maximum coverage radius of the cell. The longer the CP, the larger the coverage area of the cell. In the design, the CP and the guard period (GP) are positively correlated, so the CP determines the size of the cell radius.

[0096] Orthogonal Frequency Division Multiplexing (OFDM) is a modulation and demodulation technique widely used in wireless communications, which divides a high-speed data stream into multiple low-speed data streams to reduce the impact of frequency-selective fading in multipath transmission and improve channel utilization. Specific modulation methods can use digital modulation techniques such as Quadrature Amplitude Modulation (QAM) and Phase Shift Keying (PSK). Modulation symbols will be mapped to each subcarrier to generate OFDM symbols. The length of the OFDM symbol is usually a power of 2 to facilitate Fast Fourier Transform (FFT) calculations in the time and frequency domains.

[0097] OFDM symbol synchronization is mainly calculated and determined using the autocorrelation of the time domain signal, i.e., a signal of OFDM symbol length is received in the time domain, which has certain correlation characteristics, such as front-back conjugate correlation, center-symmetric correlation, and self-defined correlation. These sequences can be generated by specific frequency domain coding or composed of self-defined sequences. Among them, the even subcarriers carry data in the frequency domain coding characteristics, and after inverse Fourier transform, the time domain signal has the characteristics of front-back symmetry.

[0098] The Schmidl algorithm is an OFDM symbol synchronization algorithm based on a training sequence, proposed by Timothy Schmidl and Donald Cox, mainly used for timing synchronization and frequency offset estimation in OFDM systems. The training sequence usually consists of two OFDM symbols. The first symbol is composed of two identical parts in the time domain, which can be used for symbol timing synchronization and estimation of fractional frequency offset. The second training symbol has a differential relationship between the data modulated on the even subcarriers and the corresponding data of the first symbol, which is used for integer frequency offset estimation. This algorithm uses the correlation between the first symbol of the training sequence and the second symbol to perform timing synchronization. Since the first symbol has the same front and back halves, the impact of carrier frequency offset is only a phase rotation. Taking the conjugate of the front half data and multiplying it with the corresponding (interval T / 2) data of the back half, the channel impact can be eliminated, and only a phase difference of φ=πT△f exists (where T is the symbol period and △f is the carrier frequency offset). In the starting part of the training symbol, each pair of corresponding data is multiplied, and this phase difference will accumulate, and the timing metric value can be obtained by calculating the correlation function. The Schmidl algorithm has a "flat" region when determining symbol synchronization, and the length of this region is consistent with the length of the cyclic prefix.

[0099] Please refer to Figure 2In a possible implementation, in the step of assigning a unique cyclic prefix CP length to each wireless terminal by the access point AP, each wireless terminal periodically reports service data to the access point AP;

[0100] As shown in Figure 3 After the access point AP receives the service data periodically reported by the wireless terminal, the access point AP assigns a unique cyclic prefix CP length to the corresponding wireless terminal according to the identification of the wireless terminal and the wake-up allocation scheme of the cyclic prefix CP length;

[0101] When the access point AP issues an instruction of a wake-up cyclic prefix CP length to the wireless terminal, the wireless terminal sets a symbol synchronization parameter after receiving the instruction of the wake-up cyclic prefix CP length;

[0102] When the access point AP needs to perform temporary data collection before the next periodic reporting of service data by the wireless terminal, the access point AP issues a cyclic prefix CP-based wake-up time domain signal, and the cyclic prefix CP-based wake-up time domain signal only contains one orthogonal frequency division multiplexing OFDM short training sequence data.

[0103] In a possible implementation, the selected orthogonal frequency division multiplexing OFDM short training sequence carries non-zero value data on even subcarriers in the frequency domain, and odd subcarriers carry zero data.

[0104] Inverse Fast Fourier Transform (IFFT) is performed on the orthogonal frequency division multiplexing OFDM short training sequence to form an orthogonal frequency division multiplexing OFDM time domain signal, and the orthogonal frequency division multiplexing OFDM time domain signal has the characteristic of symmetry between the first half and the second half.

[0105] According to the cyclic prefix CP length of the target wireless terminal to be woken up, the orthogonal frequency division multiplexing OFDM time domain signal is increased by a corresponding set cyclic prefix CP length.

[0106] In a possible implementation, when the wireless terminal is in a silent state and only the front-end radio frequency part is used to collect air interface wireless time domain signals, a data segment with a Fourier transform point number is selected from a starting point.

[0107] The Schmidl algorithm uses the following expression to calculate the M value of the starting point:

[0108]

[0109]

[0110]

[0111] In the formula, autocorrelation value of the received data, conjugate data value of the received data, position of the start point of the calculation sequence in the received sequence, count value, received data value, Fourier transform series, received data power spectrum density; M value of the start point of the received data;

[0112] comparing the calculated M value with the set threshold value, if the M value is greater than the threshold value, starting counting;

[0113] continuing to calculate the M value of the next moment, if the M value of the next moment is also greater than the set threshold value, continuing counting, and the process of calculating the M value and comparing with the threshold value is continuously looped until the M value is less than the threshold value;

[0114] counting the counting result, and comparing with the cyclic prefix CP length allocated by the wireless terminal itself, if the counting result is equal to the cyclic prefix CP length allocated by the wireless terminal itself, the wireless terminal exits the silence state and starts data reporting transmission; if the counting result is not equal to the cyclic prefix CP length allocated by the wireless terminal itself, the wireless terminal continues to maintain the silence state until the time of periodically reporting service data by the wireless terminal to the access point AP comes.

[0115] In a possible implementation, the cyclic prefix CP length and each set of mapping data in the mapping table of the wireless terminal contain a mapping start time;

[0116] When the access point AP allocates a unique cyclic prefix CP length to each wireless terminal, for a newly accessed wireless terminal, it is judged whether to allocate a cyclic prefix CP length, if no cyclic prefix CP length is allocated, the mapping table is searched, the first position of the cyclic prefix CP length not allocated to the wireless terminal is found, and is allocated to the corresponding wireless terminal; if no unallocated cyclic prefix CP length position is found, the longest cyclic prefix CP length is increased by 1, the mapping table length is increased, and is used as a new cyclic prefix CP length position;

[0117] For the wireless terminal to which the cyclic prefix CP length has been allocated, the mapping start time is updated to the current time;

[0118] The difference between the current time and the start time of the wireless terminal in the mapping table is periodically checked, when the difference is greater than a specified time, the mapping relationship of the corresponding wireless terminal is deleted.

[0119] The time domain wake-up method of the wireless local area network terminal of the embodiment of the present application is based on the wake-up technology of the power wireless local area network terminal with a transformed cyclic prefix, and fully utilizes the modulation characteristics of the orthogonal frequency division multiplexing signal. The method of the present application utilizes the synchronization characteristics of the OFDM symbol, adjusts the length of the cyclic prefix, and further causes the change of the platform width of the OFDM synchronization symbol, so as to realize the wake-up of the terminal. The method of the present application can realize fast wake-up, effectively improve the detection efficiency, reduce the detection cost, and reduce the power consumption level of the terminal device, and provides a solid technical foundation for realizing the terminal wake-up of the power wireless local area network with the self-controllable characteristics.

[0120] The method of the present application can be applied to the power wireless local area network communication system, and can also be integrated into the power wireless local area network communication chip based on the physical layer waveform editable technical solution, for designing the wireless local area network communication product dedicated to power, and providing strong guarantee for improving the functional value of the product. After the popularization and application of the technical achievement, a set of self-controllable power wireless local area network communication system can be constructed for the fixed places such as the transformer substation and the converter station, and the self-controllable problem of the wake-up technology in the wireless local area network communication technology of the power industry can be effectively solved, the various wake-up technologies used in the 802.11 series of similar products can be replaced, the controllability of the power wireless local area network technology can be effectively improved, and the application level of the wireless local area network in the scenes such as the transformer substation and the converter station can be improved.

[0121] Please refer to Figure 4 Another embodiment of the present application further provides a wireless local area network terminal time domain wake-up system, comprising:

[0122] A cyclic prefix CP length allocation module is configured to allocate a unique cyclic prefix CP length to each wireless terminal by the access point AP, and establish a mapping table of the cyclic prefix CP length and the wireless terminal;

[0123] A short training sequence cyclic prefix CP increasing module is configured to, based on the mapping table of the cyclic prefix CP length and the wireless terminal, when the wake-up signal is sent, the access point AP increases the cyclic prefix CP of the selected orthogonal frequency division multiplexing OFDM short training sequence by the length of the cyclic prefix CP of the target wireless terminal;

[0124] A symbol synchronization point judgment module is configured to, based on the orthogonal frequency division multiplexing OFDM short training sequence with the increased cyclic prefix CP of the corresponding length, when the wireless terminal is in a silent state, only collect the air interface wireless time domain signal through the front-end radio frequency part, calculate the collected wireless time domain signal through window sliding, and judge the symbol synchronization point through the Schmidl algorithm;

[0125] The cyclic prefix CP length comparison wake-up module is used for the wireless terminal to count the number of continuous symbol synchronization points, to obtain the cyclic prefix CP length, and to compare the cyclic prefix CP length with the cyclic prefix CP length allocated to the wireless terminal itself. If the two lengths are equal, the corresponding wireless terminal exits the silent state and is woken up.

[0126] In a possible implementation, the cyclic prefix CP length allocation module allocates a unique cyclic prefix CP length to each wireless terminal when the access point AP periodically receives service data from each wireless terminal. After the access point AP receives the service data periodically reported by the wireless terminal, the access point AP allocates a unique cyclic prefix CP length to the corresponding wireless terminal according to the wake-up allocation scheme of the wireless terminal identifier and the cyclic prefix CP length.

[0127] When the access point AP issues an instruction to wake up the cyclic prefix CP length to the wireless terminal, the wireless terminal sets the symbol synchronization parameter after receiving the instruction to wake up the cyclic prefix CP length.

[0128] The access point AP issues a cyclic prefix CP-based wake-up time domain signal when the access point AP needs to temporarily collect data before the next periodic reporting of service data by the wireless terminal. The cyclic prefix CP-based wake-up time domain signal only contains one orthogonal frequency division multiplexing OFDM short training sequence data.

[0129] In a possible implementation, the short training sequence cyclic prefix CP addition module adds a cyclic prefix CP of a corresponding length to the selected orthogonal frequency division multiplexing OFDM short training sequence. The selected orthogonal frequency division multiplexing OFDM short training sequence carries non-zero value data on even subcarriers in the frequency domain, and the odd subcarriers carry zero data.

[0130] The short training sequence cyclic prefix CP addition module performs inverse Fourier transform on the orthogonal frequency division multiplexing OFDM short training sequence to form an orthogonal frequency division multiplexing OFDM time domain signal. The orthogonal frequency division multiplexing OFDM time domain signal has the characteristic of symmetry between the first half and the second half.

[0131] According to the cyclic prefix CP length of the target wireless terminal that needs to be woken up, the orthogonal frequency division multiplexing OFDM time domain signal is added with a corresponding set cyclic prefix CP length.

[0132] In a possible implementation, the symbol synchronization point judgment module selects a data segment with a Fourier transform point number from the starting point when the wireless terminal is in a silent state and only collects air interface wireless time domain signals through a front-end radio frequency part. The Schmidl algorithm uses the following expression to calculate the M value of the starting point:

[0133]

[0134]

[0135]

[0136] wherein, is a correlation value of the received data before and after, is a conjugate data value of the received data, is a position of the start point of the calculation sequence in the received sequence, is a count value, is a received data value, is a Fourier transform series, is a received data power spectral density; is an M value of the start point of the received data;

[0137] The cyclic prefix CP length comparison wake-up module compares the calculated M value with a set threshold value, and if the M value is greater than the threshold value, counting is started;

[0138] The M value of the next moment is continuously calculated, and if the M value of the next moment is also greater than the set threshold value, counting is continuously performed. The process of calculating the M value and comparing with the threshold value is continuously performed in a loop until the M value is less than the threshold value, and the process is stopped;

[0139] The counting result is counted and compared with the cyclic prefix CP length of the wireless terminal itself, and if the counting result is equal to the cyclic prefix CP length of the wireless terminal itself, the wireless terminal exits the silent state and starts data reporting transmission; if the counting result is not equal to the cyclic prefix CP length of the wireless terminal itself, the wireless terminal continues to maintain the silent state until the time of periodically reporting service data to the access point AP comes.

[0140] In a possible implementation, the cyclic prefix CP length allocation module establishes a mapping table of the cyclic prefix CP length and the wireless terminal, and each group of mapping data in the mapping table contains a mapping start time;

[0141] When the access point AP allocates a unique cyclic prefix CP length to each wireless terminal, for a newly accessed wireless terminal, it is determined whether to allocate a cyclic prefix CP length. If no cyclic prefix CP length is allocated, the mapping table is searched, the first position of the cyclic prefix CP length not allocated to the wireless terminal is found, and the corresponding wireless terminal is allocated; if no unallocated cyclic prefix CP length position is found, the longest cyclic prefix CP length is increased by 1, and the mapping table length is increased as a new cyclic prefix CP length position;

[0142] For a wireless terminal to which a cyclic prefix CP length has been allocated, the mapping start time is updated to the current time;

[0143] Periodically check the difference between the current time of the wireless terminal and the start time in the mapping table, and when the difference is greater than a specified time, delete the mapping relationship corresponding to the wireless terminal.

[0144] Another embodiment of the present application also provides an electronic device, comprising a processor and a memory, wherein the processor is configured to execute a computer program stored in the memory to implement the wireless LAN terminal time domain wake-up method.

[0145] Another embodiment of the present application also provides a computer readable storage medium, wherein the computer readable storage medium stores at least one instruction, and the at least one instruction is configured to implement the wireless LAN terminal time domain wake-up method when executed by a processor.

[0146] The computer program includes computer program code, which can be in the form of source code, object code, executable code, or some intermediate form. The computer readable storage medium can include any entity or device capable of carrying the computer program code, media, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the computer readable medium can include appropriate contents according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals. For the convenience of description, the above contents only show the parts related to the embodiments of the present application, and the specific technical details are not disclosed, please refer to the method part of the embodiments of the present application. The computer readable storage medium is non-transitory, which can be stored in the storage device formed by various electronic devices, and can realize the execution process recorded in the embodiments of the present application.

[0147] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented 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.

[0148] 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 should 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.

[0149] 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.

[0150] 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.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for time domain wake-up of a wireless local area network terminal, characterized in that, The method comprises the following steps: an access point (AP) assigns a unique cyclic prefix (CP) length to each wireless terminal and establishes a mapping table of the cyclic prefix (CP) length and the wireless terminal; based on the mapping table of the cyclic prefix (CP) length and the wireless terminal, when sending a wake-up signal, the access point (AP) adds a cyclic prefix (CP) of a corresponding length to a selected orthogonal frequency division multiplexing (OFDM) short training sequence according to the cyclic prefix (CP) length of a target wireless terminal; based on the orthogonal frequency division multiplexing (OFDM) short training sequence with the added cyclic prefix (CP) of the corresponding length, when the wireless terminal is in a silent state, only the front-end radio frequency part is used to collect air interface wireless time domain signals, and window sliding calculation is performed on the collected wireless time domain signals to determine a symbol synchronization point by using the Schmidl algorithm; the wireless terminal counts the number of continuous symbol synchronization points to obtain the cyclic prefix (CP) length, and compares the cyclic prefix (CP) length with the cyclic prefix (CP) length assigned to the wireless terminal itself, if the two lengths are equal, the corresponding wireless terminal exits the silent state and is woken up.

2. The method of claim 1, wherein the wireless LAN terminal is a wireless LAN terminal for a mobile station. In the step of assigning a unique cyclic prefix (CP) length to each wireless terminal by the access point (AP), each wireless terminal periodically reports service data to the access point (AP), and after the access point (AP) receives the service data periodically reported by the wireless terminal, the access point (AP) assigns a unique cyclic prefix (CP) length to the corresponding wireless terminal according to the identification of the wireless terminal and the wake-up allocation scheme of the cyclic prefix (CP) length; When the access point (AP) issues a wake-up cyclic prefix (CP) length instruction to the wireless terminal, the wireless terminal sets a symbol synchronization parameter after receiving the wake-up cyclic prefix (CP) length instruction; When the access point (AP) needs to temporarily collect data before the next periodic reporting of service data by the wireless terminal, the access point (AP) issues a wake-up time domain signal based on the cyclic prefix (CP), and the wake-up time domain signal based on the cyclic prefix (CP) only contains one orthogonal frequency division multiplexing (OFDM) short training sequence data.

3. The method of claim 1, wherein the wireless LAN terminal is a wireless LAN terminal for a mobile station. The selected orthogonal frequency division multiplexing (OFDM) short training sequence carries non-zero value data on even subcarriers in the frequency domain, and odd subcarriers carry zero value data; inverse Fourier transform is performed on the orthogonal frequency division multiplexing (OFDM) short training sequence to form an orthogonal frequency division multiplexing (OFDM) time domain signal, and the orthogonal frequency division multiplexing (OFDM) time domain signal has the characteristic of symmetry between the first half and the second half; a corresponding set cyclic prefix (CP) length is added to the orthogonal frequency division multiplexing (OFDM) time domain signal according to the cyclic prefix (CP) length of the target wireless terminal that needs to be woken up.

4. The method of claim 3, wherein the wireless LAN terminal is a wireless LAN terminal according to IEEE 802.11, and the time domain is a time domain of a beacon interval of the wireless LAN terminal. When the wireless terminal is in a silent state and only the front-end radio frequency part is used to collect air interface wireless time domain signals, a data segment with a length of the Fourier transform point number is selected from the starting point; the Schmidl algorithm uses the following expression to calculate the M value of the starting point: wherein is a value of autocorrelation of the reception data before and after, is a value of conjugate data of the reception data, is a position of the start point of the calculation sequence in the reception sequence, is a count value, is a value of the reception data, is a Fourier transform series, is a power spectral density of the reception data; is an M value of the start point of the reception data; The calculated M value is compared with a set threshold value, if the M value is greater than the threshold value, counting is started; The M value of the next moment is continuously calculated, if the M value of the next moment is also greater than the set threshold value, counting is continuously performed, the calculation of the M value and the comparison with the threshold value are continuously performed in a loop, and the process is stopped when the M value is less than the threshold value. The statistical counting result is compared with the cyclic prefix CP length allocated by the wireless terminal itself, if the counting result is equal to the cyclic prefix CP length allocated by the wireless terminal itself, the wireless terminal exits the silence state and starts data reporting transmission; if the counting result is not equal to the cyclic prefix CP length allocated by the wireless terminal itself, the wireless terminal continues to keep the silence state until the time for the wireless terminal to periodically report service data to the access point AP arrives.

5. The method of claim 1, wherein the wireless LAN terminal is a wireless LAN terminal for a mobile station. The cyclic prefix CP length and each set of mapping data in the mapping table of the wireless terminal contain a mapping start time; When the access point AP allocates a unique cyclic prefix CP length to each wireless terminal, for a newly accessed wireless terminal, it is determined whether to allocate a cyclic prefix CP length, if no cyclic prefix CP length is allocated, the mapping table is searched, the first position of the cyclic prefix CP length not allocated to the wireless terminal is found, and is allocated to the corresponding wireless terminal; if no position of the cyclic prefix CP length not allocated is found, the longest cyclic prefix CP length is increased by 1, the length of the mapping table is increased, and is used as a new position of the cyclic prefix CP length; For the wireless terminal to which the cyclic prefix CP length has been allocated, the mapping start time is updated to the current time; The difference between the current time and the start time of the wireless terminal in the mapping table is periodically checked, when the difference is greater than a specified time, the mapping relationship of the corresponding wireless terminal is deleted.

6. A wireless local area network terminal time domain wake-up system, characterized by Comprise: A cyclic prefix CP length allocation module, configured to allocate a unique cyclic prefix CP length to each wireless terminal by the access point AP, and establish a mapping table of the cyclic prefix CP length and the wireless terminal; A short training sequence cyclic prefix CP increasing module, configured to, based on the mapping table of the cyclic prefix CP length and the wireless terminal, when a wake-up signal is sent, the access point AP increases a cyclic prefix CP of a corresponding length to a selected orthogonal frequency division multiplexing OFDM short training sequence according to the cyclic prefix CP length of the target wireless terminal; A symbol synchronization point judgment module, configured to, based on the orthogonal frequency division multiplexing OFDM short training sequence with the cyclic prefix CP of the corresponding length, when the wireless terminal is in a silence state, only collect air interface wireless time domain signals through a front-end radio frequency part, calculate the collected wireless time domain signals through window sliding, and judge a symbol synchronization point through a Schmidl algorithm; A cyclic prefix CP length comparison wake-up module, configured to, the wireless terminal counts the number of continuous symbol synchronization points, obtains a cyclic prefix CP length, and compares the cyclic prefix CP length with the cyclic prefix CP length allocated by the wireless terminal itself, if they are equal, the corresponding wireless terminal exits the silence state and is woken up.

7. The system of claim 6, wherein the wireless LAN terminal is further configured to: The cyclic prefix CP length allocation module allocates a unique cyclic prefix CP length to each wireless terminal by the access point AP, each wireless terminal periodically reports service data to the access point AP, and the access point AP allocates a unique cyclic prefix CP length to the corresponding wireless terminal according to the identification of the wireless terminal and the wake-up allocation scheme of the cyclic prefix CP length after receiving the service data periodically reported by the wireless terminal. When the access point AP sends the wireless terminal the instruction of the wake-up cycle prefix CP length, the wireless terminal sets the symbol synchronization parameter after receiving the instruction of the wake-up cycle prefix CP length; The access point AP sends the wake-up time domain signal based on the cycle prefix CP when it needs to collect data temporarily before the next periodic data reporting of the wireless terminal, and the wake-up time domain signal based on the cycle prefix CP only contains one orthogonal frequency division multiplexing OFDM short training sequence data.

8. The system of claim 6, wherein the wireless LAN terminal time domain wake-up system further comprises: a time domain wake-up signal generator for generating a time domain wake-up signal; and a time domain wake-up signal transmitter for transmitting the time domain wake-up signal to the wireless LAN terminal. When the short training sequence cycle prefix CP increasing module increases the selected orthogonal frequency division multiplexing OFDM short training sequence with the corresponding length of the cycle prefix CP, the selected orthogonal frequency division multiplexing OFDM short training sequence carries non-zero value data on the even subcarriers in the frequency domain, and the odd subcarriers carry zero value data. The short training sequence cycle prefix CP increasing module performs inverse Fourier transform on the orthogonal frequency division multiplexing OFDM short training sequence to form the orthogonal frequency division multiplexing OFDM time domain signal, and the orthogonal frequency division multiplexing OFDM time domain signal has the characteristic of symmetry between the first half and the second half. The orthogonal frequency division multiplexing OFDM time domain signal is increased with the corresponding set cycle prefix CP length according to the cycle prefix CP length of the target wireless terminal that needs to be woken up.

9. The system of claim 8, wherein the wireless LAN terminal is further configured to: When the wireless terminal is in the silent state and only the front-end radio frequency part collects the air interface wireless time domain signal, the symbol synchronization point judgment module selects the data segment with the length of the Fourier transform point number from the starting point. wherein is a value of autocorrelation of the reception data before and after, is a value of conjugate data of the reception data, is a position of the start point of the calculation sequence in the reception sequence, is a count value, is a value of the reception data, is a Fourier transform series, is a power spectral density of the reception data; is an M value of the start point of the reception data; The cycle prefix CP length comparison and wake-up module compares the calculated M value with the set threshold value, and if the M value is greater than the threshold value, the counting starts. The next M value is continuously calculated, and if the next M value is also greater than the set threshold value, the counting continues, and the process of continuously calculating the M value and comparing the M value with the threshold value is repeated until the M value is less than the threshold value. The counting result is compared with the cycle prefix CP length allocated by the wireless terminal itself, and if the counting result is equal to the cycle prefix CP length allocated by the wireless terminal itself, the wireless terminal exits the silent state and starts data reporting transmission; if the counting result is not equal to the cycle prefix CP length allocated by the wireless terminal itself, the wireless terminal continues to remain in the silent state until the time for the wireless terminal to periodically report the service data to the access point AP arrives.

10. The wireless local area network terminal time domain wake-up system of claim 6, wherein, The mapping table of the cycle prefix CP length and the wireless terminal established by the cycle prefix CP length allocation module contains one mapping starting time in each group of mapping data. When the access point AP allocates a unique cycle prefix CP length to each wireless terminal, it is judged whether to allocate a cycle prefix CP length to the newly accessed wireless terminal. If no cycle prefix CP length is allocated, the mapping table is searched to find the first cycle prefix CP length position not allocated to the wireless terminal and allocated to the corresponding wireless terminal. If no unallocated cycle prefix CP length position is found, the longest cycle prefix CP length is increased by 1 to increase the mapping table length as a new cycle prefix CP length position. For the wireless terminal which has been allocated the cyclic prefix (CP) length, the mapping start time is updated as the current time; Periodically check the difference between the current time and the start time of the wireless terminal in the mapping table, and delete the mapping relationship of the corresponding wireless terminal when the difference is greater than the specified time.

11. An electronic device, comprising: The wireless local area network terminal time domain wake-up method comprises a processor and a memory, and the processor is used for executing a computer program stored in the memory to realize the wireless local area network terminal time domain wake-up method according to any one of claims 1 to 5.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores at least one instruction, and the at least one instruction is executed by the processor to realize the wireless local area network terminal time domain wake-up method according to any one of claims 1 to 5.

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