System and method for detecting beacon transmission timing offset in a wireless network

Abstract

A system and method are provided for adaptively optimizing a wake-up schedule of a client station in a wireless network to enable efficient and reliable communication. By analyzing one or more received beacon frames and classifying them as current or previous beacon frames, the client station determines whether the access point sent a beacon frame early. In response to detecting that a received beacon frame is a current beacon frame, a lead time is calculated based on a transmission time and a target time of the received beacon frame. The client station wakes up early enough using the lead time to reliably receive the beacon frame while minimizing unnecessary power consumption.

Description

Technical Field

[0001] The technical field of this disclosure generally relates to wireless communication, and more specifically, to a system and method for adaptive wake-up scheduling optimization of client stations in a wireless network. Background Technology

[0002] This disclosure generally relates to wireless communication systems, and more specifically to wireless networks (e.g., WLANs). In a wireless network, an access point periodically sends beacon frames to announce the presence of the network and allow client stations to connect and maintain the connection. To conserve battery power, battery-powered client stations, such as mobile phones and laptops, typically enter a power-saving mode between data transmissions. Summary of the Invention

[0003] An adaptive optimization method for wake-up scheduling of a client station involves: predicting a target beacon transmission time (TBTT) by one or more processors of the client station; receiving a beacon frame from an access point via a transceiver of the client station, the beacon frame including a transmission time according to the clock of the access point; determining, by one or more processors of the client station, that the transmission time is less than the TBTT, indicating that the beacon frame should be transmitted before the TBTT; in response to determining that the transmission time is less than the TBTT, performing a beacon frame classification process by one or more processors of the client station; determining, based on a beacon frame received during the beacon frame classification process being identified as the current beacon frame, that the access point should transmit the beacon frame before the TBTT; determining a lead time by one or more processors of the client station based on the transmission time and the TBTT; and waking up the client station by one or more processors of the client station at the lead time before a subsequent TBTT to receive subsequent beacon frames.

[0004] In one embodiment, the client station includes one or more processors and a non-transitory memory for storing instructions, configuring the client station to perform these steps when the instructions are executed by the one or more processors.

[0005] In another embodiment, a non-transitory computer-readable storage medium includes instructions that, when executed by a computer, configure the computer to perform these steps. Attached Figure Description

[0006] To facilitate identification of any particular element or action being discussed, the highest significant digit in the reference numerals refers to the numeral that was first introduced for that element.

[0007] Figure 1 This is a schematic diagram illustrating a network environment based on some examples.

[0008] Figure 2 This is a block diagram showing sample components of a client site based on some examples.

[0009] Figure 3 This is a conceptual diagram showing the components of an example beacon frame according to some examples, and a timeline showing the beacon frame transmission from the access point and the wake-up time of the client station for receiving the beacon frame.

[0010] Figure 4 This is a conceptual diagram showing two timelines illustrating example timing for sending beacon frames from an access point to a client station using network traffic, based on some examples.

[0011] Figure 5 This is a conceptual diagram showing two timelines of the example beacon frame classification process based on some examples.

[0012] Figure 6A and 6B This is a flowchart illustrating a method for adaptively optimizing wake-up scheduling for client stations, based on some examples.

[0013] Figure 7 These are schematic diagrams based on some example client sites. Detailed Implementation

[0014] The following description includes systems, methods, techniques, instruction sequences, and computer machine program products embodying exemplary embodiments of the present disclosure. In the following description, numerous specific details are set forth for purposes of explanation in order to provide an understanding of various embodiments of the subject matter of the invention. However, embodiments of the subject matter of the invention may be practiced without these specific details and will be apparent to those skilled in the art. Generally, it is not necessary to show in detail well-known examples of instructions, protocols, structures, and techniques. In the examples provided below, time units are described in milliseconds (ms); however, the system and methods are not limited to any particular time unit. In some examples, microseconds (μs) are used instead of milliseconds to obtain more precise time values.

[0015] Figure 1 This is a schematic diagram illustrating a network environment 100 according to some examples.

[0016] Network environment 100 includes network 102, access point 104, client station 106, and client station 108. Network environment 100 represents the configuration of devices and connections within a wireless communication environment.

[0017] Access point 104 connects to network 102 and acts as an intermediary between network 102 and wireless devices such as client station 106 and client station 108. Client station 106 may be included in a device such as a smartphone or laptop. Client station 106 is wirelessly connected to network 102 via access point 104. This connection enables client station 106 to access network resources, communicate with other devices, and exchange data. In some examples, from the perspective of client station 108, client station 106 acts as access point 104.

[0018] Figure 2 This is a block diagram showing sample components of a client site based on some examples.

[0019] The client station 106 includes an RX component 202, a beacon frame analysis component 204, and a sleep / wake controller 206. The RX component 202 is communicatively connected to the beacon frame analysis component 204, and the beacon frame analysis component 204 is communicatively connected to the sleep / wake controller 206.

[0020] RX component 202 receives wireless signals at client station 106. In some examples, the wireless signals received by client station 106 include beacon frames broadcast from access point 104.

[0021] The beacon frame analysis component 204 analyzes the received beacon frames. The beacon frame analysis component 204 may further include a target beacon transmission time (TBTT) calculation component 208, a transmission time determination component 210, a beacon frame classifier 212, and a lead time determination component 214.

[0022] The TBTT calculation component 208 calculates the TBTT of a beacon frame. The TBTT can refer to the scheduled time for access point 104 to send beacon frames. Beacon frames can be sent by access point 104 at regular intervals to maintain connectivity with client stations and / or APs in network 102 and / or to provide them with information. Each beacon frame has a corresponding TBTT, which specifies when access point 104 should send each beacon frame. A given beacon frame can be referred to as a "previous," "current," or "following" beacon frame relative to other beacon frames. Specifically, a previous beacon frame has a corresponding previous TBTT and refers to a beacon frame sent before the current beacon frame. A subsequent beacon frame has a corresponding subsequent TBTT and refers to a beacon frame sent after the current beacon frame. The TBTT serves as the goal or purpose for access point 104 to send beacon frames at predefined times. However, due to factors such as network congestion, manufacturer settings, and / or configurations, the actual transmission time of a beacon frame may differ from the TBTT. Normally, the current beacon frame corresponding to the current TBTT should be received at or near the current TBTT; however, due to internet traffic delays, previous beacon frames corresponding to previous TBTTs may be received at or near the current TBTT.

[0023] The transmission time determination component 210 can determine the transmission time of a received beacon frame. In some examples, the transmission time indicates the time when the beacon header is transmitted to the air interface. In some examples, the transmission time determination component 210 determines the transmission time of the received beacon frame based on a timestamp (e.g., a TSF value) extracted from the received beacon frame. Alternatively, the transmission time determination component 210 can determine the transmission time based on when the client station 106 receives the received beacon frame. In some examples, the transmission time determination component 210 determines that the transmission time is less than the calculated TBTT, indicating that the received beacon frame was transmitted before its corresponding TBTT.

[0024] Beacon frame classifier 212 classifies received beacon frames. For example, beacon frame classifier 212 determines that a received beacon frame is the current beacon frame based on whether the wireless medium remains unoccupied for one or more predetermined time periods after the received beacon frame is received (i.e., no other beacon frames for the current TBTT are received). The wireless medium can refer to the radio frequency (RF) channel or bandwidth used to transmit wireless signals, including beacon frames, between devices (e.g., access points, client stations, etc.) in a wireless network (e.g., network 102). It acts as the communication medium of the wireless network.

[0025] The lead time determination component 214 calculates one or more lead times based on the transmission time of one or more current beacon frames and the TBTT.

[0026] The sleep / wake controller 206 wakes up the client station 106 at a calculated lead time prior to the subsequent TBTT to receive subsequent beacon frames. This allows the client station 106 to reliably receive beacon frames from the access point 104, which transmits beacon frames prior to the TBTT.

[0027] Figure 3 This is a conceptual diagram showing the components of an example beacon frame according to some examples, and a timeline showing the beacon frame transmission from the access point and the wake-up time of the client station for receiving the beacon frame.

[0028] Timeline 316 shows the interval at which beacon frame 302 is sent from access point 104 to client station 106 and the time it takes for client station 106 to wake up to receive beacon frame 302.

[0029] Beacon frame 302 includes a beacon header 04 and a beacon body 306.

[0030] The Beacon Header 304 is the first part of the beacon frame. In some examples, the Beacon Header 304 is the first 24 bytes of the beacon frame. In some examples, the Beacon Header 304 is the Radio Media Address Control (MAC) Header 308. The MAC Header 308 indicates the type of frame. In some examples, the MAC Header 308 indicates that the frame being transmitted is a beacon frame.

[0031] The beacon body 306 may include additional information carried by the beacon frame 302. In some examples, the beacon body 306 includes a timing synchronization function (TSF) 310. The TSF 310 is a counter indicating the length of time since the access point 104 was powered on. In other words, the TSF 310 may be a timestamp indicating when the TSF field of the beacon frame was sent to the air interface.

[0032] Timeline 316 illustrates the periodic transmission of beacon frames from access point 104 to client station 106, the lead time 312 calculated by client station 106, and the timing at which client station 106 wakes up from power-saving mode before the transmission of each beacon frame according to the lead time 312. After receiving a beacon frame, client station 106 can return to power-saving mode (e.g., sleep) until client station 106 wakes up in the next interval.

[0033] The lead time or wake-up advance 312 is the amount of time before the expected TBTT (Breakpoint Time To Begins) for transmitting the corresponding beacon frame. Client station 106 can wake from power-saving mode at the lead time 312 before the TBTT. If the lead time 312 is too large, client station 106 may wake up earlier than necessary, wasting energy; however, if the lead time 312 is too small, client station 106 may wake up too late and miss the corresponding beacon frame. The lead time 312 can take one or more factors into account. In some examples, the lead time 312 includes one or more components that take into account the time required for hardware components to prepare to receive data (e.g., activating RX component 202) and the buffer time required for access point 104 to transmit the beacon frame before the TBTT. In a particular example, with a 2ms lead time and a subsequent TBTT of 302.4ms, client station 106 wakes up from power-saving mode at 300.4ms.

[0034] Figure 4 This is a conceptual diagram showing two timelines illustrating example timing for sending beacon frames from an access point to a client station using network traffic, based on some examples.

[0035] In some examples, due to various reasons, such as adapting to network congestion, access point 104 intentionally sends beacon frame 302 before TBTT. Figure 4In the example shown, access point 104 transmits a beacon frame 1.2 ms before its TBTT. The TBTT of the first beacon frame is 102.4 ms, but access point 104 transmits the first beacon frame at 101.2 ms, earlier than 102.4 ms. The TBTT of the second beacon frame is 204.8 ms, but access point 104 attempts to transmit the second beacon frame before its TBTT; however, due to internet traffic, access point 104 cannot transmit the second beacon frame at the scheduled time (e.g., 204.8 - 1.2 = 203.6 ms), so access point 104 transmits the second beacon frame at 209.2 ms after the wireless interface (e.g., wireless medium, RF interface, radio communication interface) has become idle. The TBTT of the third beacon frame is 307.2 ms, but access point 104 transmits the third beacon frame at 306.0 ms, 1.2 ms earlier than its TBTT. The TBTT of the eighth beacon frame is 819.2 ms. Access point 104 attempts to send the eighth beacon frame at 818.0 ms, but due to internet traffic, access point 104 cannot send the eighth beacon frame at 818.0 ms. Therefore, in response to the radio medium not being occupied, access point 104 sends the eighth beacon frame at 920.3 ms. Upon receiving the eighth beacon frame at 920.3 ms, which is close to the ninth TBTT, client station 106 needs to determine whether the eighth beacon frame is a ninth beacon frame sent before the ninth TBTT or a delayed eighth beacon frame. To make this determination, client station 106 waits for a predetermined time period to see if it receives the ninth beacon frame (i.e., the current beacon frame); if so, it indicates that the eighth beacon frame is a delayed eighth beacon frame (i.e., the previous beacon frame); if not, it indicates that the received beacon frame is the current beacon frame. The length of the predetermined time period will be... Figure 5 The description is discussed therein.

[0036] Figure 5 This is a conceptual diagram showing two timelines of the example beacon frame classification process based on some examples.

[0037] As described above, CCA allows client station 106 to check for other transmissions based on the radio frequency (RF) signal and / or energy level in the wireless medium: if the RF signal and / or energy level is above a predetermined threshold, client station 106 determines that one or more other transmissions exist. Alternatively, if no RF signal and / or energy level exceeds the predetermined threshold, client station 106 determines that the wireless medium remains unoccupied when performing CCA. In some examples, access point 104 periodically transmits beacon frames at or near the TBTT. In response to receiving or transmitting a received beacon frame, client stations (e.g., client station 106) and / or APs with data to transmit must wait for the Distributed Interframe Space (DIFS) before transmission to allow the wireless medium to remain idle. In some examples, a random backoff mechanism is used to avoid collisions when multiple client stations and / or APs are ready to transmit after the DIFS. The backoff time is a random value between 0 and the Contention Window (CW), where CW starts at the minimum contention window (CWMin) and increases exponentially to the maximum contention window (CWMax) with each successive collision. In some examples, the duration of the CCA process is equal to the combined duration of DIFS and CWMax. In some examples, the backoff mechanism allows the client station and / or AP to randomly delay their transmissions for a period of time based on the current contention window size, aiming to minimize collisions. Therefore, to determine whether other beacon frames will be received, the client station 106 may need to wait for a predetermined period of time, including the combined duration of DIFS and CWMax. By waiting for a predetermined period of time equal to DIFS + CWMax after receiving the received beacon frame, the client station 106 allows sufficient time to elapse if any other beacon frame transmission is expected. If no other transmission is detected during this period (i.e., no other beacon frames are received), the client station 106 can conclude that the received beacon frame is likely the current beacon frame, rather than a delayed previous beacon frame.

[0038] In some examples, client station 106 sends a Request to Send (RTS) to access point 104 after a predetermined time period. In some examples, after client station 106 sends the RTS, the AP is busy and unable to respond to the RTS due to reasons such as ongoing data transmission from a hidden node. In other examples, in response to receiving the RTS, access point 104 can send a Clear to Send (CTS) to notify all client stations, APs, and / or hidden nodes in network 102 to wait for the current transmission to complete, thereby gaining control of the radio interface. Furthermore, access point 104 can also send pending non-beacon packets and / or pending beacon frames that were not sent due to busy radio media. Since the radio media has been reserved for the RTS, access point 104 can send pending non-beacon packets and / or pending beacon frames after the CTS.

[0039] Once the RTS-CTS exchange (i.e., sending RTS and receiving CTS) is complete, all client stations will need to wait for the DIFS period before competing again. After DIFS, the random backoff mechanism can be used again. The client station selects a random backoff time between 0 and the current CW value. If the collision continues, the CW will again grow exponentially, reaching CWMax. Therefore, to determine whether to receive the current beacon frame, client station 106 waits for another predetermined period (i.e., the combined duration of DIFS and CWMax).

[0040] In some examples, client station 106 may repeat the cycle of sending RTS, receiving CTS, and checking other transmissions one or more times within a predetermined time period until there is insufficient remaining time for another cycle before the subsequent TBTT. In other words, client station 106 may first determine whether there is enough remaining time to complete another cycle before needing to receive subsequent beacon frames. If the remaining time is insufficient, the client station ends the determination process by determining that the received beacon frame is the current beacon frame and prepares to receive subsequent beacon frames at or before the subsequent TBTT.

[0041] In some examples, client station 106 calculates the remaining time based on the subsequent TBTT, the end of one of the scheduled time periods, and / or the current time value of the client station's clock, and then determines whether there is sufficient remaining time by comparing the remaining time with the time required for the RTS-CTS exchange and other scheduled time periods. In some other examples, client station 106 adds the time required for the RTS-CTS exchange and other scheduled time periods to the current time value to determine whether there is sufficient time for another loop.

[0042] Figure 6AThis is a flowchart illustrating an adaptive optimization method 600 for wake-up scheduling for a client station, based on some examples. Method 600 includes blocks 602, 604, 606, 608, 610, and 612. It should be understood that the blocks depicted in the flowchart are not limited to the specific order in which they are presented. The order of operations may vary, and performing the process may not require all blocks. Without departing from the scope of the disclosed method, some blocks may be performed in a different order, simultaneously, omitted entirely, or other blocks may be included. This flowchart is for illustrative purposes only and should not be construed as a limitation on the methods or systems described herein. The described process is flexible and can be adapted to various implementations within the scope of those skilled in the art.

[0043] In box 602, the client station predicts the TBTT. The TBTT can be predicted by the TBTT calculation component 208. The TBTT indicates the time when a beacon frame is scheduled to be sent. In some examples, the TBTT calculation component 208 predetermines the TBTT. For example, TBTT = (N+1) × a predetermined beacon interval. N is the interval number corresponding to the beacon frame. For example, the first beacon frame sent by access point 104 has a corresponding interval number 1, the second beacon frame sent by access point 104 has a corresponding interval number 2, and so on. Figure 4 In the examples shown, the TBTT is 102.4, 204.8, 307.2, ..., 819.2, and 921.6 milliseconds (ms), meaning the beacon frame is scheduled to be sent every 102.4 ms. In some examples, the current TBTT is determined based on the transmission time of the previous beacon frame. In these examples, the TBTT calculation component 208 determines the current beacon interval by dividing the transmission time of the previous beacon frame by the floor division of the predetermined beacon interval. For example: 110.0 / / 102.4 = 1, where 110.0 is the transmission time of the previous beacon frame, 102.4 is the predetermined beacon interval, and 1 indicates that the interval number corresponding to the previous frame is 1, and the interval number corresponding to the current beacon frame is 2 (i.e., 1+1). Therefore, the current TBTT will be twice the predetermined beacon interval (i.e., 2 × 102.4 = 204.8). In response to determining the current TBTT, the client station 106 proceeds to box 604.

[0044] In block 604, client station 106 receives a beacon frame (i.e., the received beacon frame) from access point 104. The received beacon frame may be received by the RX component 202 of client station 106 at or near the current TBTT. RX component 202 may include a transceiver for receiving data such as beacon frames from access point 104. Transmission time determination component 210 may determine the transmission time of the received beacon frame. In response to determining the transmission time, client station 106 proceeds to block 606.

[0045] In box 606, client station 106 determines via beacon frame analysis component 204 that the transmission time of the received beacon frame is less than the predicted TBTT of the current beacon frame. When the transmission time is less than the predicted TBTT, it indicates that the beacon frame may have been transmitted before the TBTT. However, further confirmation is needed because the received beacon frame may be a previous beacon frame received before the TBTT of the current beacon frame due to internet traffic delays, rather than because the current beacon frame was transmitted before its TBTT. Client station 106 proceeds to box 608 to confirm that the received beacon frame is the current beacon frame and not a previous beacon frame.

[0046] In box 608, client station 106 performs a beacon frame classification process to determine whether a received beacon frame is a current beacon frame or a previous beacon frame. The beacon frame classification process can be performed by beacon frame classifier 212. Beacon frame classifier 212 can determine that the received beacon frame is the current beacon frame based on the absence of other beacon frames detected within a predetermined time period, because if the received beacon frame were a delayed previous beacon frame, client station 106 should receive other beacon frames intended to become the current beacon frame after a certain period. Beacon frame classifier 212 can also determine that the received beacon frame is a previous beacon frame based on other beacon frames received during the predetermined time period. Details of the beacon frame classification process will be provided later. Figure 6B This is discussed further in the description. In response to determining that the received beacon frame is the current beacon frame, client station 106 continues to frame 610.

[0047] In box 610, client station 106 determines the lead time. The lead time determines the extent to which TBTT client station 106 should exit power-saving mode (i.e., wake up). The lead time can be determined by lead time determination component 214. In response to determining that the received beacon frame is the current beacon frame, indicating that the current beacon frame was indeed sent before its TBTT, lead time determination component 214 can determine the lead time based on how much earlier the current beacon frame was sent and / or received than the current TBTT. As described above, the lead time can include one or more components. In some examples, one component of the lead time is determined based on the difference between the transmission time and the current TBTT. In some examples, one component of the lead time = the transmission time of the current beacon frame - the current TBTT, obtaining the negative time of that component. In these examples, assuming the other components of the lead time are 0, client station 106 wakes up at the subsequent TBTT + lead time to prepare for receiving subsequent beacon frames. In some other examples, the lead time = current TBTT - transmission time of the current beacon frame, obtaining a positive time for one component of the lead time. In these examples, again assuming the other components of the lead time are 0, client station 106 wakes up at the subsequent TBTT - lead time to prepare for receiving the subsequent TBTT. In response to determining the lead time, client station 106 proceeds to box 612.

[0048] In some examples, client station 106 repeats frames 602, 604, 606, 608, and 610 a predetermined number of times to obtain multiple lead times. The lead time determination component 214 can select the lead time with the largest absolute value from the multiple lead times, thereby minimizing the risk that client station 106 wakes up too late and misses the beacon frame.

[0049] In box 612, client station 106 wakes up from power-saving mode based on subsequent TBTT and lead time. Client station 106 can be woken up by sleep / wake controller 206. Sleep / wake controller 206 controls the timing of entering or exiting power-saving mode. In some examples, sleep / wake controller 206 tracks time based on the client station's clock and, in response to the client station's clock reaching a wake-up time determined by TBTT, lead time, and any other time required to prepare client station 106, instructs client station 106 to exit power-saving mode.

[0050] Figure 6BThis is a flowchart illustrating further details of box 608 according to some examples. It should be understood that the boxes depicted in the flowchart are not limited to the specific order in which they are presented. The order of operations may vary, and performing the process may not require all boxes. Some boxes may be performed in a different order, simultaneously, omitted entirely, or may include other steps without departing from the scope of the disclosed methods. This flowchart is for illustrative purposes only and should not be construed as a limitation on the methods or systems described herein. The described processes are flexible and can be adapted to various implementations within the scope of those skilled in the art.

[0051] In box 608, client station 106 performs a beacon frame classification process, which may include boxes 614, 616, 618 and 620.

[0052] In box 614, client station 106 checks for other transmissions from access point 104 within a predetermined time period. This check can be performed by beacon frame classifier 212. Client station 106 can check for other beacon frame transmissions from access point 104 after receiving a received beacon frame. By checking for other beacon frame transmissions, client station 106 can determine whether the received beacon frame is the current beacon frame or a delayed previous beacon frame.

[0053] Client station 106 can check for other transmissions from access point 104 by performing Clear Channel Assessment (CCA). CCA allows client station 106 to check for other transmissions based on radio frequency (RF) signals and / or energy levels in the wireless medium: if the RF signal and / or energy level is above a predetermined threshold, client station 106 determines that one or more other transmissions exist. Alternatively, if no RF signal and / or energy level exceeds the predetermined threshold, client station 106 determines that the wireless medium remains unoccupied when performing CCA. Client station 106 can perform CCA within a predetermined time period. In addition to CCA, client station 106 can also determine the existence of one or more other transmissions based on data received from access point 104 (e.g., received beacon frames, non-beacon packets, etc.).

[0054] In response to receiving a beacon frame from access point 104, client station 106 may initiate box 614 to check for other transmissions from access point 104 within a predetermined time period. Alternatively, client station 106 may initiate box 614 in response to receiving a CTS from access point 104 in box 618, as will be discussed below. Optionally, client station 106 may continue to box 620 in response to receiving other transmissions from access point 104 or the expiration of the predetermined time period.

[0055] In one example, client station 106 determines that the wireless medium is not occupied during a predetermined time period and does not receive other transmissions, and continues to box 616.

[0056] In another example, client station 106 receives additional beacon frames for the current TBTT, indicating that the received beacon frame is a delayed previous beacon frame. Client station 106 proceeds to box 620 to classify the received beacon frame as a previous beacon frame, and then proceeds to box 610.

[0057] In another example, client station 106 receives non-beacon packets. Client station 106 continues to perform CCA (Continuous Complaint Action) for a predetermined period of time to check for other transmissions.

[0058] In box 616, client station 106 may send an RTS to access point 104. As described above, by sending an RTS to access point 104, access point 104 may send a CTS in response, and then send pending beacon frames that were not sent due to busy radio media. In other words, if other beacon frames are available for the current TBTT, sending an RTS will cause access point 104 to send other beacon frames after the CTS. Client station 106 may continue to box 618 in response to sending an RTS.

[0059] In some examples, before sending the RTS to access point 104, client station 106 determines whether there is sufficient remaining time before the subsequent TBTT to complete the cycle of sending the RTS, receiving the CTS from access point 104, and checking other transmissions within the predetermined time period. If yes, client station 106 can continue sending the RTS and execute box 618; if not, client station 106 can terminate the beacon frame classification process and prepare to receive subsequent beacon frames.

[0060] In box 618, client station 106 checks the CTS from access point 104. The CTS check can be performed by RX component 202. In one example, client station 106 receives the CTS and begins box 614 to check for other transmissions from access point 104, as other beacon frames may be sent by access point 104. In another example, client station 106 fails to receive the CTS from access point 104, indicating that access point 104 is communicating with other client stations in network 102, and client station 106 can either terminate or restart the beacon frame classification process.

[0061] In box 620, client station 106 classifies a received beacon frame as a current beacon frame or a previous beacon frame based on other transmissions (e.g., other beacon frames and non-beacon packets) from access point 104 within a predetermined time period or their absence.

[0062] In some examples, the beacon frame classifier 212 classifies the received beacon frame as the current beacon frame based on the fact that no other transmissions have occurred within a predetermined time period, and then ends the beacon frame classification process.

[0063] In some other examples, beacon frame classifier 212 classifies received beacon frames as previous beacon frames based on other beacon frames received by client station 106 for the current TBTT. Client station 106 then proceeds to box 610.

[0064] Figure 7 This is a schematic diagram of client station 700, in which instructions 710 (e.g., software, programs, applications, applets, apps, or other executable code) can be executed to cause client station 700 to perform any one or more of the methods discussed herein. For example, instructions 710 can cause client station 700 to perform any one or more of the methods described herein. Instructions 710 can transform a general, non-programmed client station 700 into a specific client station 700 programmed to perform the functions described and illustrated in the manner stated. Client station 700 can operate as a standalone device or be coupled (e.g., networked) to other machines. In a networked deployment, client station 700 can operate as a server machine or a client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. Client station 700 may include, but is not limited to, server computers, client computers, personal computers (PCs), tablets, laptops, netbooks, set-top boxes (STBs), entertainment media systems, cellular phones, smartphones, mobile devices, wearable devices (e.g., smartwatches), smart home devices (e.g., smart appliances), other smart devices, network devices, network routers, network switches, network bridges, or any machine capable of sequentially or otherwise executing instructions 710 that specify the actions to be taken by client station 700. Furthermore, while a single client station 700 is shown, the term "machine" can include a collection of machines that individually or jointly execute instructions 710 to perform any one or more of the methods discussed herein.

[0065] Client station 700 may include processor 704, memory 706, and I / O components 702, which may be configured to communicate via bus 740. In some examples, processor 704 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a radio frequency integrated circuit (RFIC), other processors, or any suitable combination thereof) may include, for example, processors 708 and 712 that execute instruction 710. The term "processor" is intended to include multi-core processors, which may include two or more independent processors (sometimes referred to as "cores") capable of executing instruction 710 simultaneously. Although Figure 7 Multiple processors 704 are shown, but client station 700 may include a single processor with a single core, a single processor with multiple cores (e.g., a multi-core processor), multiple processors with a single core, multiple processors with multiple cores, or any combination thereof.

[0066] Memory 706 includes main memory 714, static memory 716, and memory cell 718, both of which are accessible by processor 704 via bus 740. Main memory 706, static memory 716, and memory cell 718 store instructions 710 embodying any one or more of the methods or functions described herein. During execution of instructions 710 by client station 700, instructions 710 may also reside wholly or partially in main memory 714, static memory 716, machine-readable storage medium 720, memory cell 718, processor 704 (e.g., processor cache memory), or any suitable combination thereof.

[0067] I / O component 702 may include various components for receiving input, providing output, generating output, sending information, exchanging information, or capturing measurements. The specific I / O component 702 included in a particular machine depends on the type of machine. For example, portable machines such as mobile phones may include touch input devices or other such input mechanisms, while headless server machines may not include such touch input devices. I / O component 702 may include... Figure 7Many other components are not shown. In various examples, I / O component 702 may include output component 726 and input component 728. Output component 726 may include visual components (e.g., displays such as plasma display panels (PDPs), light-emitting diode (LED) displays, liquid crystal displays (LCDs), projectors, or cathode ray tube (CRT) displays), sound components (e.g., speakers), haptic components (e.g., vibration motors, resistance mechanisms), or other signal generators. Input component 728 may include alphanumeric input components (e.g., keyboards, touchscreens configured to receive alphanumeric input, photoelectric keyboards, or other alphanumeric input devices), point-based input components (e.g., mice, touchpads, trackballs, joysticks, motion sensors, or other indicating instruments), haptic input components (e.g., physical buttons, touchscreens providing position and / or force for touch or touch gestures, or other haptic input components), audio input components (e.g., microphones), etc.

[0068] In a further example, I / O component 702 may include a range of other components such as biometric component 730, motion component 732, environmental component 734, or position component 736. For example, biometric component 730 includes components for detecting facial expressions (e.g., hand gestures, facial expressions, vocal expressions, body posture, or eye tracking), measuring biosignals (e.g., blood pressure, heart rate, body temperature, sweat, or brain waves), or identifying a person (e.g., voice recognition, retinal recognition, facial recognition, fingerprint recognition, or EEG-based recognition). Motion component 732 includes accelerometer components (e.g., accelerometers), gravity sensor components, and rotation sensor components (e.g., gyroscopes). Environmental component 734 includes, for example, one or more cameras, an illumination sensor component (e.g., a photometer), a temperature sensor component (e.g., one or more thermometers that detect ambient temperature), a humidity sensor component, a pressure sensor component (e.g., a barometer), an acoustic sensor component (e.g., one or more microphones that detect background noise), a proximity sensor component (e.g., an infrared sensor that detects nearby objects), a gas sensor (e.g., a gas detection sensor for the safe detection of hazardous gas concentrations or for measuring pollutants in the atmosphere), or other components that can provide indications, measurements, or signals corresponding to the surrounding physical environment. Position component 736 includes a position sensor component (e.g., a Global Positioning System (GPS) receiver component), an altitude sensor component (e.g., an altimeter or barometer that detects air pressure from which altitude is derived), an orientation sensor component (e.g., a magnetometer), etc.

[0069] Communication can be achieved through a variety of technologies. I / O component 702 also includes a communication component 738, which can connect client station 700 to network 722 or device 724 via its respective coupling or connection. For example, communication component 738 may include a network interface component or other suitable device interfaced with network 722. In further examples, communication component 738 may include wired communication components, wireless communication components, cellular communication components, near field communication (NFC) components, Bluetooth components (e.g., Bluetooth Low Energy), Wi-Fi components, and other communication components to provide communication in other ways. Device 724 can be another machine or any of various peripheral devices (e.g., a peripheral device coupled via USB).

[0070] Furthermore, the communication component 738 can detect identifiers or include components capable of detecting identifiers. For example, the communication component 738 may include a radio frequency identification (RFID) tag reader component, an NFC smart tag detection component, an optical reader component (e.g., an optical sensor for detecting one-dimensional barcodes (e.g., Universal Product Code (UPC) barcodes), multi-dimensional barcodes (e.g., Quick Response (QR) codes, Aztec codes, data matrices, data glyphs, Maxi codes, PDF417, Ultra codes, UCC RSS-2D barcodes, and other optical codes)), or a sound detection component (e.g., a microphone for identifying tag audio signals). Additionally, various information can be derived via the communication component 738, such as location via Internet Protocol (IP) geolocation, etc. The location of the signal triangulation, or the location of the NFC beacon signal that can be detected to indicate a specific location.

[0071] Various memories (e.g., main memory 714, static memory 716, and / or the memory of processor 704) and / or memory units 718 may store one or more sets of instructions and data structures (e.g., software) that embody or are used for any one or more methods or functions described herein. When executed by processor 704, these instructions (e.g., instruction 710) cause various operations to implement the disclosed examples.

[0072] Instruction 710 can be sent or received via network 722, using a transmission wireless medium, through a network interface device (e.g., the network interface component in communication component 738), and using any of several well-known transmission protocols (e.g., Hypertext Transfer Protocol (HTTP)). Similarly, instruction 710 can be sent or received using a transmission medium via coupling (e.g., peer-to-peer coupling) to device 724.

[0073] The described system and method provide an efficient technique for adaptive optimization of wake-up scheduling for client stations in wireless networks. By analyzing and classifying the transmission times of received beacon frames, the client station determines whether the access point has transmitted the beacon frame before the target time. Once detected, the client station calculates a lead time based on the time difference. Using this lead time allows the client station to wake up early enough to reliably receive the beacon frame while minimizing unnecessary power consumption.

[0074] Key advantages may include: optimizing the wake-up time scheduling of the client station to match the beacon frames sent in advance by the access point, and reducing the power consumption of the client station by avoiding premature exit from power-saving mode. Overall, this invention adaptively optimizes the wake-up time scheduling of the client station to achieve efficient and reliable wireless communication.

[0075] The following are example systems and methods for adaptive optimization of wake-up scheduling for client stations in wireless networks:

[0076] Example 1 is a method comprising: predicting a target beacon transmission time (TBTT) by one or more processors at a client station; receiving a beacon frame from an access point via a transceiver at the client station, the beacon frame including a transmission time according to the clock of the access point; determining, by one or more processors at the client station, that the transmission time is less than the TBTT, indicating that the beacon frame be transmitted before the TBTT; in response to determining that the transmission time is less than the TBTT, performing a beacon frame classification process by one or more processors at the client station; determining, based on a beacon frame received during the beacon frame classification process being identified as the current beacon frame, that the access point transmits the beacon frame before the TBTT; determining a lead time by one or more processors at the client station based on the transmission time and the TBTT; and waking up the client station by the lead time before a subsequent TBTT to receive subsequent beacon frames.

[0077] In Example 2, the subject of Example 1 includes: repeating the prediction a predetermined number of times, receiving, determining that the transmission time is less than TBTT, executing, determining that the access point transmits a beacon frame before TBTT, and determining a lead time to obtain multiple lead times; and selecting the lead time with the largest absolute value from the multiple lead times as the lead time.

[0078] In Example 3, the subject matter of Examples 1-2 includes the beacon frame classification process comprising: determining that the radio medium remains unoccupied for a predetermined time period including the Distributed Inter-Frame Spacing (DIFS) and the Contention Window Maximum (CWMax); and determining that the radio medium remains unoccupied for the predetermined time period indicates that the received beacon frame is the current beacon frame.

[0079] In Example 4, the subject matter of Examples 1-3 includes the following, wherein the beacon frame classification process includes: determining that the radio medium remains unoccupied for a first predetermined time period including a distributed inter-frame gap (DIFS) and a contention window maximum (CWMax); sending a request transmission (RTS) to the access point; checking for a clear transmission (CTS) from the access point; checking for other beacon frames in a subsequent predetermined time period equal to the first predetermined time period; and indicating that the received beacon frame is the current beacon frame if no other beacon frames are received in the subsequent predetermined time period.

[0080] In Example 5, the subject matter of Examples 1-4 includes the following, wherein the beacon frame classification process comprises: determining that the radio medium remains unoccupied for a first predetermined time period including a distributed inter-frame gap (DIFS) and a contention window maximum (CWMax); sending a request transmission (RTS) to the access point; checking for a clear transmission (CTS) from the access point; checking for other beacon frames for a subsequent predetermined time period equal to the first predetermined time period; detecting that no other beacon frames are received during the subsequent predetermined time period; repeating the steps of sending the RTS, checking the CTS, and checking for other beacon frames one or more times; and obtaining multiple unreceived detections by repeating the sending of the RTS, checking the CTS, and checking for other beacon frames, indicating that the received beacon frame is the current beacon frame.

[0081] In Example 6, the subject matter of Examples 1-5 includes the following, wherein the beacon frame classification process includes: determining that the radio medium remains unoccupied for a first predetermined time period including a distributed inter-frame gap (DIFS) and a contention window maximum (CWMax); sending a request transmission (RTS) to the access point; checking for a clear transmission (CTS) from the access point; checking for other beacon frames in a subsequent predetermined time period equal to the first predetermined time period; and receiving other beacon frames from the access point in the subsequent predetermined time period; and determining, in response to receiving the other beacon frames, that the received beacon frame is a previous beacon frame.

[0082] In Example 7, the subject matter of Examples 1-6 includes the following, wherein the beacon frame classification process comprises: determining that the radio medium remains unoccupied for a first predetermined time period including a distributed inter-frame gap (DIFS) and a contention window maximum (CWMax); sending a request to transmit (RTS) to the access point; checking for a clear transmission (CTS) from the access point; checking for other beacon frames in subsequent predetermined time periods equal to the first predetermined time period; receiving non-beacon data packets from the access point in the subsequent predetermined time periods; repeating the steps of sending the RTS, checking the CTS, and checking for other beacon frames one or more times; and indicating that the received beacon frame is the current beacon frame if no other beacon frame is received in one or more subsequent predetermined time periods.

[0083] In Example 8, the subject of Example 7 includes: predicting subsequent TBTTs of subsequent beacon frames; determining the time required for RTS-CTS switching; determining that there is sufficient time for RTS-CTS switching, and checking the other beacon frames based on the time required for RTS-CTS switching and a predetermined time period before the repetition.

[0084] In Example 9, the subject matter of Examples 1-8 includes the following, wherein the beacon frame classification process includes: determining that the radio medium remains unoccupied for a first predetermined time period including a distributed inter-frame gap (DIFS) and a contention window maximum (CWMax); sending a request transmission (RTS) to the access point; detecting that no clear transmission (CTS) has been received from the access point; and terminating the beacon frame classification process in response to detecting that the CTS has not been received.

[0085] In Example 10, the subject of Examples 1-9 includes the beacon frame classification process comprising: receiving other beacon frames from the access point; and in response to receiving the other beacon frames, determining that the received beacon frame is a previous beacon frame.

[0086] Example 11 is a client site that includes a device that implements any of Examples 1-10.

[0087] Example 12 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement any one of Examples 1-10.

Claims

1. A method for detecting timing deviation in beacon transmission in a wireless network, characterized in that, include: Predict the Target Beacon Transmission Time (TBTT) using one or more processors at the client station; The client station receives beacon frames from the access point via its transceiver, the beacon frames including the transmission time according to the access point's clock. If one or more processors at the client station determine that the transmission time is less than the TBTT, they indicate that the beacon frame is transmitted before the TBTT. In response to determining that the transmission time is less than the TBTT, one or more processors of the client station perform a beacon frame classification process; Based on the beacon frame received during the beacon frame classification process being identified as the current beacon frame, one or more processors of the client station determine that the access point will send a beacon frame before TBTT; The lead time is determined by one or more processors at the client station based on the transmission time and the TBTT; as well as The client station is woken up by one or more processors at the pre-time prior to the subsequent TBTT to receive the subsequent beacon frame.

2. The method according to claim 1, characterized in that, Also includes: Repeat the steps of prediction, reception, determining that the transmission time is less than TBTT, performing the classification process, determining that the access point will send a beacon frame before TBTT, and determining the lead time, repeating the process a predetermined number of times to obtain multiple lead times; as well as The preceding time with the largest absolute value is selected from the plurality of preceding times as the preceding time.

3. The method according to claim 1, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a predetermined period, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); and Determine that the wireless medium remains unoccupied during the predetermined time period, and indicate that the received beacon frame is the current beacon frame.

4. The method according to claim 1, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; and If no other beacon frames are received within the subsequent predetermined time period, it indicates that the received beacon frame is the current beacon frame.

5. The method according to claim 1, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; No other beacon frames were detected during the subsequent predetermined time period; Repeat the steps of sending RTS, checking CTS, and checking other beacon frames once or multiple times; and By repeatedly sending RTS, checking CTS, and checking other beacon frames to obtain multiple unreceived detections, the received beacon frame is indicated to be the current beacon frame.

6. The method according to claim 1, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; Receive other beacon frames from the access point during the subsequent predetermined time period; and In response to receiving the other beacon frames, it is determined that the received beacon frame is a previous beacon frame.

7. The method according to claim 1, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; Receive non-beacon data packets from the access point during the subsequent predetermined time period; Repeat the steps of sending RTS, checking CTS, and checking other beacon frames once or multiple times; and If no other beacon frame is received within one or more subsequent predetermined time periods, it indicates that the received beacon frame is the current beacon frame.

8. The method according to claim 7, characterized in that, Also includes: Predict the subsequent TBTT of subsequent beacon frames; Determine the time required for RTS-CTS exchange; Ensure that there is sufficient time for RTS-CTS exchange, and check the other beacon frames based on the time required for the RTS-CTS exchange and a predetermined time period before the repetition.

9. The method according to claim 1, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); No Clear Send (CTS) was received from the access point; and In response to the detection that the CTS has not been received, the beacon frame classification process is terminated.

10. The method according to claim 1, characterized in that, The beacon frame classification process includes: Receive other beacon frames from the access point; and In response to receiving the other beacon frames, it is determined that the received beacon frame is a previous beacon frame.

11. A client website, characterized in that, include: One or more processors; as well as A non-transitory memory storing instructions that, when executed by the one or more processors, configure the one or more processors to: Predict the target beacon transmission time (TBTT); The client station receives beacon frames from the access point via its transceiver. The beacon frames include a transmission time based on the access point's clock. Determining that the transmission time is less than the TBTT indicates that the beacon frame was transmitted before the TBTT; In response to determining that the transmission time is less than the TBTT, a beacon frame classification process is performed; Based on the beacon frame received during the beacon frame classification process being identified as the current beacon frame, it is determined that the access point sent the beacon frame before the TBTT. The lead time is determined based on the transmission time and the TBTT; as well as The client station is woken up at the lead time before the subsequent TBTT to receive the subsequent beacon frames.

12. The client station according to claim 11, characterized in that, The instruction also configures the client station as follows: Repeat the steps of prediction, reception, determining that the transmission time is less than TBTT, performing the classification process, determining that the access point will send a beacon frame before TBTT, and determining the lead time, repeating the process a predetermined number of times to obtain multiple lead times; as well as Select the preceding time with the largest absolute value from among the multiple preceding times as the preceding time.

13. The client station according to claim 11, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a predetermined period, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); and Determine that the wireless medium remains unoccupied during the predetermined time period, and indicate that the received beacon frame is the current beacon frame.

14. The client station according to claim 11, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; and If no other beacon frames are received within the subsequent predetermined time period, it indicates that the received beacon frame is the current beacon frame.

15. The client station according to claim 11, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; No other beacon frames were detected during the subsequent predetermined time period; Repeat the steps of sending RTS, checking CTS, and checking other beacon frames once or multiple times; and By repeatedly sending RTS, checking CTS, and checking other beacon frames to obtain multiple unreceived detections, the received beacon frame is indicated to be the current beacon frame.

16. The client station according to claim 11, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; Receive other beacon frames from the access point during the subsequent predetermined time period; and In response to receiving the other beacon frames, it is determined that the received beacon frame is a previous beacon frame.

17. The client station according to claim 11, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); Check the Clear Send (CTS) from the access point; Inspect other beacon frames within a subsequent predetermined time period equal to the first predetermined time period; Receive non-beacon data packets from the access point during the subsequent predetermined time period; Repeat the steps of sending RTS, checking CTS, and checking other beacon frames once or multiple times; and If no other beacon frame is received within one or more subsequent predetermined time periods, it indicates that the received beacon frame is the current beacon frame.

18. The client station according to claim 17, characterized in that, The beacon frame classification process includes: Predict the subsequent TBTT of subsequent beacon frames; Determine the time required for RTS-CTS exchange; and Ensure that there is sufficient time for RTS-CTS exchange, and check other beacon frames based on the time required for the RTS-CTS exchange and a predetermined time period before the repetition.

19. The client station according to claim 11, characterized in that, The beacon frame classification process includes: Determine that the radio medium remains unoccupied for a first predetermined period of time, including the Distributed Inter-Frame Inter-Frame Interval (DIFS) and the Contention Window Maximum (CWMax); Send a request to the access point (RTS); No Clear Send (CTS) was received from the access point; and In response to the detection that the CTS has not been received, the beacon frame classification process is terminated.

20. A non-transitory computer-readable storage medium comprising instructions that, when executed by one or more processors of a client station, configure the client station to: Predict the target beacon transmission time (TBTT); The client station receives beacon frames from the access point via its transceiver, the beacon frames including the transmission time according to the access point's clock. Determining that the transmission time is less than the TBTT indicates that the beacon frame was transmitted before the TBTT; In response to determining that the transmission time is less than the TBTT, a beacon frame classification process is performed; Based on the beacon frame received during the beacon frame classification process being identified as the current beacon frame, it is determined that the access point sent the beacon frame before the TBTT. The lead time is determined based on the transmission time and the TBTT; as well as The client station is woken up at the lead time before the subsequent TBTT to receive the subsequent beacon frames.

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