Systems and methods for efficient wake-up for beacon reception

Abstract

The present application discloses systems and methods for efficient wake-up for beacon reception. According to an embodiment, systems and methods are disclosed for efficient wake-up in wireless communication devices (140, 150, 160) to receive beacons (210, 212) without significantly affecting battery power and data throughput. The wireless devices (140, 150, 160) receive beacons from network elements such as access points (180). If beacons (210, 212) are not received within a defined interval according to a schedule, then the wireless devices (140, 150, 160) determine a pattern of beacon reception timing and use a weighted score process to select the best possible timing pattern and use it as a schedule for receiving beacons on an ongoing basis, thus avoiding staying awake all the time to receive misaligned beacons.

Description

[0001] This application is a divisional application of the Chinese patent application with the application number 2016112716149 and the title "System and Method for Effective Wake-up for Beacon Reception", which was filed on December 30, 2016. Technical Field

[0002] The present disclosure generally relates to the field of wireless communication, and more particularly to beacon reception in a wireless communication network. Background Art

[0003] In a wireless communication network such as a wireless local area network (WLAN), communication management packets / frames are used to communicate information about the network. These frames are called beacons. Beacons are sent by network elements such as access points (APs) and include basic information about the network to establish a connection with, maintain a connection with, and communicate with network elements, such as network IDs, communication parameters, supported data rates, network capabilities, and other relevant information required for any wireless device (e.g., cellular phone, PDA, laptop computer, or any other device capable of wireless communication in the network).

[0004] Beacons are periodically sent to wireless devices in the network at regular intervals (e.g., 100 ms, 50 ms, 102.4 ms, 204.8 ms, etc.) to maintain their connections with network elements and perform many other connection management related functions. The beacon interval is communicated to wireless devices in the network at the moment of connection establishment, so that the wireless devices can receive beacons at a predetermined time and maintain their connections with network elements. Generally, the beacon interval is a default value selected by the device manufacturer of the network element and the interval remains fixed in the network.

[0005] Typically, when a wireless device is in an idle state and not performing any tasks, in order to conserve battery power, the wireless device enters "sleep" in a power-saving mode and "wakes up" after a set interval (e.g., every 100 ms) to receive beacons from a network element and maintain a connection with the network. Although beacons are sent at a given interval, due to various conditions such as clock synchronization misalignment, environmental conditions, network traffic congestion, etc., the beacon interval can drift. In this case, the wireless device can miss a beacon, and either assume that the network element is no longer available and start searching for another network element, or stay awake and continue to monitor the network environment until they receive the next beacon. If the beacon interval has drifted for a long time, then in order to maintain a connection with the network, the wireless device stays awake and remains on the channel for the entire duration of the beacon interval to continuously monitor the network for beacons. When the wireless device scans the network for beacons, since it requests the wireless device to change the channel for data transmission, these wireless devices pause sending and receiving data packets, which can cause the wireless device to miss another beacon. This causes the wireless device to relatively quickly lose battery power when connected to a wireless network (especially when connected to a WLAN AP), and also affects the data throughput in the wireless network. Summary of the Invention

[0006] According to one embodiment, a device is disclosed. The device includes a transceiver and a processing unit coupled to the transceiver. The processing unit is configured to receive a predetermined number of beacons from a network element, determine a receive timing pattern for the predetermined number of beacons, and use the determined receive timing pattern to further receive beacons from the network element, wherein the at least one beacon among the predetermined number of beacons is received before or after a scheduled receive time for the at least one beacon.

[0007] According to another embodiment, a method is disclosed. The method includes receiving, by a processing unit, a predetermined number of beacons from a network element, determining a receive timing pattern for the predetermined number of beacons, and using the determined receive timing pattern to further receive beacons from the network element, wherein the at least one beacon among the predetermined number of beacons is received before or after a scheduled receive time for the at least one beacon.

[0008] According to yet another embodiment, a device is disclosed. The device includes a transceiver for sending and receiving data packets; and a processing unit coupled to the transceiver and configured to: receive a predetermined number of beacons from a network element, determine a reception timing pattern for the predetermined number of beacons, determine a score for each of the reception timing patterns, and use a reception timing pattern having at least one of the lowest score or the highest score to further receive beacons from the network element; wherein the at least one of the predetermined number of beacons is received before or after a scheduled reception time for at least one beacon. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Illustrates an exemplary wireless network according to one embodiment.

[0010] Figures 2A - 2C Illustrates an exemplary pattern of beacon reception timing according to another embodiment.

[0011] Figure 3 Illustrates an exemplary flowchart for determining an unaligned beacon pattern for effective wake-up according to one embodiment. DETAILED DESCRIPTION

[0012] The following description provides many different embodiments or examples for implementing different features of the subject matter. These descriptions are for illustrative purposes only and do not limit the scope of the present invention.

[0013] Reference Figure 1 , an exemplary wireless network 100 is illustrated according to one embodiment. Network 100 includes a network element 110. The network element 110 can be any wireless communication network element, for example, an access point capable of connecting to the network, a network repeater, a network extender, a wireless router, or any other device, and the network element 110 can provide a wireless communication connection to various devices. The network element 110 includes a transceiver 112, a processor 114, a storage device 116, and an antenna 118 among various other system components. Although simple elements are shown for explanation; the network element 110 can have various other system components and multiple elements, for example, the network element 110 can have multiple processors, antennas, storage devices, transceivers, displays, user interfaces, etc.

[0014] The network element 110 is communicatively coupled to a backend network device 120 and a network 130. The network element 110 can be coupled to various other networks and systems to provide network services. For example, the network element 110 can be connected to content servers, the Internet, cellular networks, media service providers, routers, etc. Additionally, the network element 110 can be connected to these systems via wired or wireless communication links or a combination thereof. The network 100 includes various wireless communication devices such as, for example, a cellular phone 140, a laptop computer 150, and a personal digital assistant device (PDA) 160. The network 100 can also include many other devices that can communicate wirelessly with the network element 110, such as control systems, printers, customer electronic devices, and various other devices and systems. Additionally, the network element 110 can also be communicatively coupled to other network elements in a mesh network scenario. Each of these devices (such as the cellular phone 140) can also include various other system components such as a transceiver 142, a processor 144, a storage device 146, and other components (not shown) such as a display, a keyboard, an antenna, etc.

[0015] When a wireless device such as, for example, the cellular phone 140 establishes communication with the network element 110, the network element 110 provides various communication-related parameters to the cellular phone 140 for the cellular phone 140 to communicate effectively with the network element 110. Among many other parameters, the network element 110 also provides beacon interval information to the cellular phone 140. For example, if the manufacturer of the network element 110 sets the beacon interval for the network element 110 at 100 milliseconds (100 ms), then the network element 110 provides that information to the cellular phone 140. Depending on the wireless communication protocol used to establish communication, the beacon information can be provided to the cellular phone 140 in various ways. For example, if the network element 110 and the cellular phone 140 can communicate with each other using the IEEE 802.11 WLAN protocol, then the beacon information will be provided in the Target Beacon Transmission Time (TBTT) field of the management frame. Similarly, for other wireless communication protocols that use beacons for connection management, this information can be provided to the cellular phone 140 in the appropriate field of the protocol-specific management frame.

[0016] In this example, after receiving beacon information, cellular phone 140 monitors the channel every 100 ms to receive beacons from network element 110. After receiving a beacon, if cellular phone 140 is not actively processing any data, then cellular phone 140 enters a power-saving idle mode to conserve battery power and wakes up again at every 100 ms interval to receive beacons from network element 110. Typically, an electronic signal includes jitter, which can cause signal misalignment. An electronic device typically includes mechanisms to adjust minor jitter in an electronic signal; however, if the signal is misaligned beyond any given threshold (which cannot be adjusted), then the signal connection is re-established to resynchronize the signal reception.

[0017] As explained above, in a conventional wireless network, when a beacon is not received according to schedule, cellular phone 140 does not terminate the connection with network element 110, but instead remains awake to monitor the channel for the next beacon from network element 110. If the beacon from network element 100 is misaligned with the scheduled timing for receiving the beacon (e.g., 100 ms), then cellular phone 140 may end up remaining awake longer to ensure that it receives the beacon from network element 110 and maintains an appropriate connection with network element 110. This causes cellular phone 140 to lose a significant amount of battery power to merely receive the beacon and results in poor data throughput. According to one embodiment, when cellular phone 140 does not receive a beacon according to schedule, cellular phone 140 initiates an efficient wake-up process to capture the beacon from network element 110, without the need to remain awake for a long time and conserve battery power.

[0018] Refer to Figure 2A , exemplary beacon reception timing pattern 200A is illustrated according to another embodiment. When communicating with a network element such as network element 110, the illustrated beacon reception timing pattern 200A can be observed at any wireless device such as cellular phone 140 (or a device such as computer 150, PDA 160, etc.). The beacon reception timing pattern 200A includes the times at which beacons are received at the wireless device. It is expected to receive beacons A - E at timings 210a - 210e with respective beacon intervals 214 - 217 at the wireless device according to wireless connection parameters. When beacons A - E are received by the wireless device, timings 212a - 212e are the actual timings. As illustrated, beacons A - E are received with minor jitter; however, the wireless device is able to adjust the jitter and receive the beacons without any significant timing issues. In this example, the wireless device continues to wake up after a given interval 214 - 217 and receives beacons A - E as expected.

[0019] Typically, due to various reasons such as clock misalignment, changes in the cyber-physical environment, etc., beacons are misaligned. For example, if a physical structure temporarily obstructs the line of sight for a network element, and its transmission has to bounce off the physical structure before reaching the device with some delay, then that transmission pattern is likely to remain the same for some time until the obstruction is removed. Similarly, if there are other reasons for misaligned beacon reception, then the misaligned beacon reception pattern remains the same until the cause of misalignment is removed.

[0020] Reference Figure 2B , according to another embodiment, an exemplary beacon reception timing pattern 200B with misaligned beacon reception is illustrated. As illustrated, beacons A - E are scheduled to be received at times 220a - 220e; however, beacon A is received at time 222a, which is 4 ms before the scheduled reception time 220a, beacon B is received as scheduled, beacon C is received at time 222c, which is 4 ms before the scheduled time 220c, beacon D is received as scheduled, and beacon E is received at time 222e, which is 4 ms before the scheduled time 220e. Conventionally, the wireless device wakes up at time 220a when beacon A is expected; however, since beacon A arrives at time 222a, which is 4 ms before the scheduled time 220a, the wireless device misses beacon A and remains awake in full-power mode until it receives beacon B, which is received as scheduled at time 220b. After receiving beacon B, the wireless device returns to "sleep" and "wakes up" at time 220c to receive beacon C; however, beacon C arrives at time 222c, which is 4 ms before the scheduled time, and the wireless device misses beacon C and remains "awake" to receive beacon D. In this example, because the wireless device is not receiving beacons as scheduled, the conventional wireless device remains awake after missing a beacon to continue capturing misaligned beacons and exhausting system resources and battery power.

[0021] Reference Figure 2C , according to another embodiment, an exemplary beacon reception timing pattern 200C with a different misaligned beacon reception pattern is illustrated. As illustrated, beacons A - E are scheduled to be received at times 230a - 230e; however, beacon A is received at time 232a, which is 4 ms before the scheduled reception time 230a, beacon B is received at time 232b, which is 8 ms before the scheduled time, beacon C is received as scheduled, beacon D is received at time 232d, which is 4 ms before the scheduled time, and beacon E is received at time 232e, which is 8 ms before the scheduled time 230e. As explained in the previous example, the conventional wireless device will remain "awake" after missing a beacon to continue receiving misaligned beacons and exhausting a large amount of battery power.

[0022] According to one embodiment, after losing a beacon, a wireless device stays awake to receive a predetermined number of misaligned beacons (e.g., 10, 20, 30, 50, etc.), and then determines the misalignment pattern of beacon reception. Based on the determination during the connection establishment process and contrary to the recommended wake-up time communicated with a network element, the wireless device adjusts its wake-up time to align its wake-up time with the misalignment pattern of beacon reception timing. This allows the wireless device to save a significant amount of battery power by avoiding staying awake to receive misaligned beacons for a wireless connection as is typically done in conventional wireless devices.

[0023] According to one embodiment, when the wireless device determines that a beacon has multiple reception patterns, the wireless device monitors the misaligned beacon reception timing pattern and calculates the best weighted pattern for the next beacon, and follows the weighted time pattern until the beacon reception pattern changes again. For example, in Figures 2A - 2C the exemplary illustration of, beacons are received according to some repeating pattern. Each pattern can be considered a hypothesis, and any statistical weighting mechanism can be used to determine the given pattern that is most likely to occur, and then the given pattern can be used as the wake-up time pattern of the wireless device to receive beacons.

[0024] In one embodiment, the beacon arrival times can be analyzed in parallel with each of the patterns from Figures 2A - 2C Then each pattern can be scored based on the actual arrival time relative to the expected arrival time.

[0025] One of many possible score calculation methods can be as follows:

[0026] Score = Score + α(|T1 - T2| - Score)

[0027] T1 = actual beacon arrival time

[0028] T2 = expected beacon arrival time

[0029] α = score factor

[0030] In an exemplary embodiment, a score value can be initialized to zero and incremented with the captured beacon pattern. After a predetermined number of beacons, if the score is below a certain threshold (such as, for example, below 5000), this can indicate that a beacon pattern has been detected. After an initial detection, the detected pattern can be used for future beacon detections. The beacon pattern is monitored and tracked periodically to ensure that the pattern has not changed during, for example, periodic monitoring and tracking. If it is determined that the score remains below, for example, the previously used threshold of 5000, then it is likely that the beacon pattern has not changed and the current pattern will be used to continue detecting beacons. If for some reason the score exceeds the previously captured threshold (e.g., 5000), then it can indicate that the beacon pattern tracking has been lost and a new acquisition phase can be restarted. Additionally, when the pattern is used to receive beacons and a beacon is lost, then it can indicate a lost tracked pattern or that the pattern has changed for various reasons, and the process for a new pattern acquisition can be restarted.

[0031] The term "score factor" in the equation above determines the algorithm sensitivity for irregular delays, which can be added on top of the detected pattern due to a determined network event. In some exemplary embodiments, a score factor of 1 / 8 can be used. Other score factors such as 1 / 4, 1 / 7, 1 / 10, 1 / 16, 1 / 20, etc. can also be used. As the score factor becomes higher, the score will tend to bounce and the beacon pattern can become challenging to monitor and track.

[0032] As the score becomes lower, the calculation more closely tracks the arrival pattern of the beacons. If the score becomes higher, then it can reflect a random beacon interval pattern, which ultimately leads to traditional wake-up methods. Those skilled in the art will understand that an exemplary weighted scoring method is illustrated for determining a weighted beacon pattern; however, the method is not limited to any specific weighted scoring scheme. Any statistical method can be used to determine the success of the best hypothesis, which is used as the beacon reception schedule.

[0033] Reference Figure 3 , a flowchart of a process 300 for determining beacon reception timing is illustrated according to another embodiment. At 310, when a wireless device receives a beacon from a network element (e.g., an access point), then at 320, the wireless device determines whether the beacon is misaligned with the scheduled timing. If the beacon is not misaligned and is received according to the schedule, then the wireless device continues to receive beacons according to the schedule. If the beacon is not received according to the schedule and it is misaligned with the actual schedule time, then at 330, the wireless device receives a predetermined number (e.g., 10, 20, 30, 50, etc.) of beacons.

[0034] At 340, the wireless device determines whether there is an alignment pattern for beacon reception timing. If there is no pattern and the beacon is randomly misaligned, then at 350, the wireless device returns to the normal scheme of staying awake to receive the misaligned beacon. If the wireless device determines that there is a pattern in receiving the misaligned beacon, then at 360, the wireless device determines a pattern such as, for example Figure 2B or Figure 2C illustrated in. At 370, the wireless device further determines whether there is more than one misalignment pattern for beacon reception timing. If there is not more than one pattern, then at 395, the wireless device uses the determined pattern of the received beacon as the schedule for receiving future beacons. If there is more than one misalignment pattern, then at 380, the wireless device calculates a weighted score for each pattern. As explained above, various statistical methods can be used to determine the weighted score. After determining the weighted score, at 390, the wireless device selects the best pattern for beacon reception, and at 395, the wireless device uses the misalignment pattern with the best score as the schedule for receiving beacons from the network element.

[0035] The features of several embodiments are outlined above so that those skilled in the art can better understand the various aspects of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to implement the same purposes and / or achieve the same advantages as the various embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructs do not depart from the spirit and scope of the present disclosure, and they can make various changes, substitutions, and modifications herein without departing from the spirit and scope of the present disclosure.

[0036] Although the subject matter has been described in language specific to structural features or method techniques or both, it should be understood that the subject matter in the appended claims should not be limited to the specific features or acts described above. Instead, the above specific features and acts are disclosed as example forms for implementing at least some of the claims. Various operations of the embodiments are provided herein. The order in which some or all of the operations are described should not be construed as implying that these operations must be order-related. Alternative orders will be understood to have the benefit of this specification. Additionally, it will be understood that not all operations will have to be present in every embodiment provided herein. Additionally, it will be understood that not all operations are required in some embodiments.

[0037] In addition, as used herein, "exemplary" is intended to serve as an example, instance, illustration, etc., and is not necessarily advantageous. Additionally, although the present disclosure has been shown and described with reference to one or more embodiments, other technical personnel within the art will know equivalent variations and modifications based on the reading and understanding of this specification and the drawings. The present disclosure includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with reference to the various functions performed by the above-described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond to (unless otherwise indicated) any component that performs the specific function of the described component (i.e., functionally equivalent), even if not structurally equivalent to the disclosed structure. In addition, although certain features of the present invention may be disclosed only with reference to one of several embodiments, such features may be combined with one or more other features of other embodiments as desired and advantageous for any given or specific application.

Claims

1. An apparatus for a beacon, the apparatus comprising: a transceiver; and a processing unit coupled to the transceiver and configured to: receive a beacon from a network element; determine whether the beacon is misaligned with a scheduling timing; when the beacon is not received as scheduled and is misaligned with the scheduling timing, receive a predetermined number of additional beacons, determine whether at least one of the additional beacons is misaligned, when an additional beacon is misaligned: calculate a weighted score for the misaligned additional beacon; select a misalignment mode based on the weighted score; and receive another beacon using the selected misalignment mode.

2. The apparatus according to claim 1, wherein the weighted score is at least partially based on a probability of repeated beacon misalignment.

3. The apparatus according to claim 1, wherein Each of one or more predetermined numbers of additional beacons arrives within an interval of at least one of the following times: 50 milliseconds, 100 milliseconds, 102.4 ms, and 204.8 ms.

4. A method for a beacon, the method comprising: receiving a beacon from a network element; determining whether the beacon is misaligned; when the beacon is not received as scheduled and is misaligned with the scheduling timing, receiving a predetermined number of additional beacons; determining whether at least one of the additional beacons is misaligned; when an additional beacon is misaligned: calculating a weighted score for the misaligned additional beacon; selecting a misalignment mode based on the weighted score; and receiving another beacon using the selected misalignment mode.

5. The method according to claim 4, wherein the weighted score is at least partially based on a probability of repeated beacon misalignment.

6. The method according to claim 4, wherein, Each of one or more predetermined numbers of additional beacons arrives within an interval of at least one of the following times: 50 milliseconds, 100 milliseconds, 102.4 ms, and 204.8 ms.

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