Method and apparatus for aligning target beacon transmission times of multi-link connections

Abstract

In embodiments of the present disclosure, a method for aligning target beacon transmit time (TBTT) of multi-link connections is provided. One method includes setting up a first link and a second link between an access point (AP) and a wireless device based on multi-link operation (MLO), and obtaining a first TBTT of the first link and a second TBTT of the second link. The method further includes aligning the first TBTT and the second TBTT at a start time, and then transmitting a beacon frame on the first link and the second link according to the alignment of the first TBTT and the second TBTT. Embodiments of the present disclosure synchronize and align the beacon TBTTs of different links, and can reduce the wake-up time on all active links, thereby saving power for the wireless device.

Description

BACKGROUND

[0001] An access point (AP) is a networking device that creates a wireless local area network (WLAN) and allows one or more stations to connect to a wide area network (WAN). An AP can establish a link with a station on a channel. Typically, an AP is connected to a router or switch via a wired or wireless network as a standalone device. An AP can also be implemented as an integrated component of a wireless router or wireless switch.

[0002] MLO (Multi-Link Operation) is a new feature introduced in IEEE 802.11be (Wi-Fi 7) and enables a non-AP MLD (Multi-Link Device) to discover, authenticate, associate, and setup multiple links with an AP MLD. After the MLO setup procedure, each link enables channel access and frame exchange between the non-AP MLD and the AP MLD, and each link can independently transmit and receive data. BRIEF DESCRIPTION OF DRAWINGS

[0003] Embodiments of the present disclosure can be understood from the following detailed description when read in connection with the accompanying drawings. In accordance with the spirit and traditions of the industry, the various features are not drawn to scale. Indeed, the dimensions of the various features can be arbitrarily increased or decreased for the sake of clarity in the discussion. Some examples of the present disclosure are described with respect to the following drawings:

[0004] Figure 1 An example environment illustrating multi-link operation (MLO) between two MLDs is illustrated;

[0005] Figure 2 An example environment illustrating channel access by two MLDs through a simultaneous transmit and receive (STR) link pair is illustrated;

[0006] Figure 3 A flow diagram illustrating an example method for aligning target beacon transmit time (TBTT) for a multi-link connection according to embodiments of the present disclosure is illustrated;

[0007] Figures 4A-4B An example illustrating alignment of TBTT for two links of MLO according to embodiments of the present disclosure is illustrated;

[0008] Figures 5A-5C Another example illustrating alignment of TBTT for three links of MLO according to embodiments of the present disclosure is illustrated;

[0009] Figures 6A-6B An example relationship between two target wake time (TWT) service periods (SPs) is illustrated;

[0010] Figures 7A-7C An example illustrating alignment of TWT start time for three links of MLO according to embodiments of the present disclosure is illustrated; and

[0011] Figure 8 An example AP MLD is illustrated in accordance with embodiments of the present disclosure. DETAILED DESCRIPTION

[0012] As discussed above, IEEE 802.11be (Wi-Fi 7) introduces new features of MLO, which enables to transmit and receive data with multiple links, and each link can independently transmit and receive data. MLO can simultaneously aggregate multiple channels on different frequency bands, and can achieve seamless flow of network traffic even if there is interference or congestion.

[0013] Traditionally, power saving coordination between multiple links of MLO is not considered. Generally, when a wireless device (such as a mobile device) wants to run in a true power saving (PS) mode, it needs to enter the PS mode in all active links. However, the wireless device can wake up in one link, while it is in PS mode for another link, which makes the overall power saving scheme of the wireless device inefficient. Therefore, there is a problem that power of the wireless device cannot be effectively saved during MLO.

[0014] Embodiments of the present disclosure propose an optimized power saving scheme for Wi-Fi multi-link connection by coordinating all links during multi-link connection, and can improve the PS mode efficiency of the wireless device by solving how to effectively save power during MLO. The present invention reduces the wake-up time on all active links by synchronizing and aligning the beacon TBTT of different links, thereby saving more power for the wireless device.

[0015] According to embodiments of the present disclosure, the TBTT of different links (such as two links, three links, etc.) are aligned at a start time, and the beacon frames of different links all start at the same start time. In this way, the beacon frames on different links are transmitted at the same time, rather than at different times, and different links can have more common inactive time. In this way, the wireless device can have more sleep time on the links, and can save more power than the traditional way.

[0016] Other advantages of embodiments of the present disclosure will be described below in conjunction with example implementation. The basic principles and several preferred embodiments of the present disclosure are explained below with reference to the accompanying drawings. Figures 1-8 DETAILED DESCRIPTION

[0017] Figure 1 An example environment 100 of MLO between two MLDs is illustrated. As Figure 1As shown in FIG. 1, the environment 100 includes an AP MLD 110 (also referred to as an AP) and a non-AP MLD, such as a station (STA) MLD 120 (also referred to as a STA). The AP MLD 110 is a networking hardware device that allows other Wi-Fi devices to connect to a WAN and provides wireless connectivity using a WLAN for other Wi-Fi devices to use the WAN. The STA MLD 120 is a device with the capability to use IEEE 802.11 protocols, and the STA MLD 120 can be a laptop computer, a desktop computer, a cellular phone, or other Wi-Fi enabled wireless device.

[0018] As used herein, an MLD is a device that is a logical entity and has more than one affiliated station, and has a single media access control (MAC) service access point (SAP) to logical link control (LLC) that includes one MAC data service. An AP MLD is an AP where each station affiliated to the MLD is an AP, and a non-AP MLD is a station that supports receiving and transmitting frames on more than one link at a time. A STA affiliated to an MLD can select and manage its capabilities and operating parameters independently of other STAs affiliated to the same MLD.

[0019] As Figure 1 As shown in FIG. 1, multiple links (link 131 and link 132) are simultaneously established between the AP MLD 110 and the STA MLD 120 using MLO, and MLO enables link aggregation at the MAC layer and simultaneously aggregates multiple channels on different frequencies. Each link can be mapped to a channel and a frequency band, for example, the first link 131 can operate at 2.4 GHz, while the second link 132 can operate at 5 GHz. For example, the STA MLD 120 can start scanning at 2.4 GHz and select 5 GHz based on out-of-band discovery, such as reduced neighbor report (RNR).

[0020] Due to the multiple links in parallel between two MLDs, higher throughput, lower latency, and higher reliability can be achieved, which is useful for a variety of scenarios, such as virtual reality (VR), augmented reality (AR), industrial Internet of Things (IoT), etc.

[0021] It should be understood that while Figure 1 two links based on MLO are shown in FIG. 1, MLO can have more links between the AP MLD 110 and the STA MLD 120. It should also be understood that while the first link 131 is shown at 2.4 GHz and the second link 132 is shown at 5 GHz, the first link 131 and / or the second link 132 can operate at other frequencies, such as 6 GHz.

[0022] Figure 2 An example environment 200 illustrating channel access of two MLDs on a simultaneous transmit and receive (STR) link pair is shown. As Figure 2 As shown in FIG. 1, an AP MLD 110 establishes two links with a STA MLD 120 based on MLO, where an AP1 111 affiliated with the AP MLD 110 has downlink traffic to a STA1 121 affiliated with the STA MLD 120, and an AP2 112 affiliated with the AP MLD 110 has uplink traffic from a STA2 122 affiliated with the STA MLD 120.

[0023] Figure 2 The AP MLD 110 and the STA MLD 120 are shown operating on the STR link pair and contending for frame exchange between the two MLDs on those links. After the AP MLD 110 has performed a multi-link setup with the STA MLD 120 to successfully setup a first link 131 and a second link 132, the AP1 111 can transmit data frames to the STA1 121 on the link 131, and the AP2 112 can receive data frames from the STA2 122 on the link 132.

[0024] For example, the STA1 121 can find the AP1 111 in order to establish an MLD setup with the AP MLD 110. That is, the STA1 121 can discover at least one AP in the AP MLD 110 to initiate authentication and MLD setup. The MLD link setup creates the links 131 and 132, and the MLD link setup signaling is transmitted on a single link. In some cases, an AP in the AP MLD 110 can be unavailable, and the STA MLD 120 can detect the availability of each AP and / or each link.

[0025] As shown in FIG. 1, each MLD owns different links (such as the links 131 and 132) on different channels and / or different frequency bands. The same traffic identifier (TID) traffic is allowed to have frame exchange on different links with a default TID mapping, and TID-to-link mapping negotiation is also optional. The TID-to-link mapping mechanism allows an AP MLD and a non-AP MLD that performs a multi-link setup to determine how to map TIDs to the setup links in downlink (DL) and uplink (UL). By default, all TIDs are mapped to all setup links in DL and UL. When two MLDs explicitly negotiate TID-to-link mapping by following the procedure, each TID can be mapped to the same or different links. Figures 1-2

[0026] ​Figure 3 FIGURE 1 illustrates a flow diagram of an example method 100 for aligning TBTTs of multi-link connections, in accordance with embodiments of the present disclosure. To better describe the method 100, reference is made to FIGURE 2, which illustrates an example of two links of a multi-link operation (MLO) being aligned in terms of target beacon transmission times (TBTTs), in accordance with embodiments of the present disclosure. Figures 4A-4B Reference is made to FIGURE 4, which illustrates an example of two links of an MLO being aligned in terms of TBTTs, in accordance with embodiments of the present disclosure.

[0027] At 302, a first link and a second link are established between an access point (AP) and a wireless device based on a multi-link operation (MLO). For example, as indicated in 400 of FIGURE 4, a first link 410 (also referred to as link 1) and a second link 420 (also referred to as link 2) of an MLO are established between two MLDs, such as an AP MLD 110 and a STA MLD 120. As shown in FIGURE 4, beacon frames 411, 412, 413, and 414 are transmitted on the link 410, and the beacon interval on the link 410 is 400 time units (TUs). Beacon frames 421, 422, 423, 424, and 425 are transmitted on the link 420, and the beacon interval on the link 420 is 300 TUs. For example, one TU is equal to 1024 microseconds. Figure 4A

[0028] As used herein, a beacon frame is one of the management frames in an IEEE 802.1 based WLAN, and it contains information about the network. Beacon frames are transmitted periodically, and they are used to announce the presence of the WLAN and to synchronize the members of the service set.

[0029] At 304, a first target beacon transmission time (TBTT) of the first link and a second TBTT of the second link are obtained. For example, as shown in 400 of FIGURE 4, the beacon frame 411 on the link 410 is transmitted at a start time T1, which can be considered as the first TBTT, while the beacon frame 421 on the link 420 is transmitted at a start time T2, which can be considered as the second TBTT. Each time a beacon is transmitted, the wireless device wakes up from a PS mode, and each wake up of the radio invokes the host CPU to wake up and consume power of the wireless device. Figure 4A

[0030] The PS mode can be a built-in mode that allows a device to save power by analyzing data usage patterns over time, and then ensuring that Wi-Fi does not consume too much battery of the device. For example, a radio device can be in one of two power states, a wake state indicating that the radio is continuously powered on and is able to receive and transmit data, and a sleep state indicating that the radio is unable to receive and transmit data and consumes lower power. The radio power state can transition between the wake state and the sleep state according to IEEE 802.11 power management rules. To save more power, it is desirable to reduce the wake-up time of the radio and / or processor, such as a CPU, on all active links. As indicated in 400 of FIGURE 4, the wireless device is in the PS mode when the radio is in the sleep state, and the wireless device is in the active mode when the radio is in the wake state. Figure 4A ​​As shown in FIG. 4A, the start time T1 and the start time T2 are not aligned, thus resulting in more wake-up time during the period T1-T3.

[0031] At 306, the first TBTT and the second TBTT are aligned at a start time. For example, as Figure 4B indicated at 450 in FIG. 4B, the start time (the second TBTT) of the beacon frame 421 on the link 420 is aligned with the start time (the first TBTT) of the beacon frame 411 on the link 410 at the start time T1. The wireless device wakes up at the start time T1 and sends the beacon frame 411 on the link 410 and the beacon frame 421 on the link 420. Figure 4B The number of wake-ups of the wireless device during the period T1-T3 in FIG. 4A is 6, while the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is 7. Thus, the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is less than that in FIG. 4A. Figure 4A The number of wake-ups of the wireless device during the period T1-T3 in FIG. 4A is 6, while the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is 7. Thus, the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is less than that in FIG. 4A. Figure 4B The number of wake-ups of the wireless device during the period T1-T3 in FIG. 4A is 6, while the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is 7. Thus, the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is less than that in FIG. 4A. Figure 4A The number of wake-ups of the wireless device during the period T1-T3 in FIG. 4A is 6, while the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is 7. Thus, the number of wake-ups of the wireless device during the period T1-T3 in FIG. 4B is less than that in FIG. 4A.

[0032] At 308, beacon frames on the first link and the second link are sent according to the alignment of the first TBTT and the second TBTT. For example, as Figure 4B indicated in FIG. 4B, after the TBTTs of the links 410 and 420 are aligned at the start time T1, the beacon frames 411, 412, 413, and 414 are sent on the link 410, and the beacon frames 421, 422, 423, 424, and 425 are sent on the link 420.

[0033] According to the method 300 of the present disclosure, an optimized power saving scheme of Wi-Fi multi-link connection can be achieved by coordinating all links during multi-link connection. The present disclosure reduces the wake-up time on all active links by synchronizing and aligning the beacon TBTTs of different links, thereby saving more power for the wireless device.

[0034] In some embodiments, a target time can be selected to align the TBTTs on different links, and the target time will be considered as the start time for sending the earliest beacon frame on each link. For example, as Figure 4B indicated in FIG. 4C, the time T1 is selected as the target time for aligning the TBTTs on different links. Alternatively, the time T2 can also be selected as the target time for aligning the TBTTs on different links.

[0035] In some embodiments, the beacon intervals for sending beacon frames on different links can be adjusted to be the same. For example, if the two beacon intervals are different, the beacon interval of one link can be adjusted to be the same as the beacon interval of the other link. In Figure 4B the example of FIG. 4D, the beacon interval on the link 420 can be adjusted from 300 TU to 400 TU. In this way, the wake-up time of the wireless device can be further reduced.

[0036] Figures 5A-5C Another example of aligning TBTTs of three links of a MLO is illustrated, and in this example, there is no offset by using beacon synchronization, in accordance with embodiments of the present disclosure. Figures 5A-5C In the example, there are three links between an AP MLD (such as the AP MLD 110) and a non-AP MLD (such as the STA MLD 120), which include a first link 510, a second link 520, and a third link 530. Each link can have a transmitted virtual AP (TX VAP) and transmit a beacon frame from the AP MLD 110 to the STA MLD 120.

[0037] In embodiments of the present disclosure, in order to save power on a wireless device (such as the STA MLD 120), it is needed to reduce the wake-up times or the wake-up ratio of the STA MLD 120, because a lower wake-up times or wake-up ratio can achieve a better power saving effect for the wireless device. In some embodiments, the wake-up ratio WR beacon may be defined as the ratio of the wake-up times in a single beacon period to the least common multiple (LCM) of the beacon intervals of all links in a time unit (such as 100 TUs). For example, the wake-up ratio WR beacon may be defined by the following equation (1).

[0038]

[0039] wherein T total represents the LCM of the beacon intervals of the links 1-n, Wakeup_times link1_n represents the total wake-up times of the links 1-n during the LCM, and n represents the number of all links between two MLDs.

[0040] After selecting the start time T start of the target period (where the time length of the target period is the LCM), the end time T end of the target period can be determined by the following equation (2).

[0041] T end = T start + T total (2)

[0042] Within the target period [T start , T end ], the wake-up points of each link can be counted, and Wakeup_times link1 , Wakeup_times link2 , …, Wakeup_times linknWakeup_times link1_n , which represents the total number of wakeups for links 1-n during the target period [T start , T end ]. In this way, the value of the wakeup ratio can be calculated to save power on the wireless device.

[0043] As indicated at 500 in Figure 5A , there is a case where there is a TBTT offset. In contrast to Figure 4A , there are three links between the AP MLD 110 and the STA MLD 120 in Figure 5A , a first link 510, a second link 520, and a third link 530. As shown in Figure 5A , beacon frames 511, 512, 513, and 514 are transmitted on the link 510, and the beacon interval on the link 510 is, for example, 400 TUs. Beacon frames 521, 522, 523, 524, and 525 are transmitted on the link 520, and the beacon interval on the link 520 is, for example, 300 TUs. Beacon frames 531, 532, 533, 534, 535, 536, 537, and 538 are transmitted on the link 530, and the beacon interval on the link 530 is, for example, 200 TUs.

[0044] Continuing to refer to Figure 5A , the beacon frame 511 on the link 510 is transmitted at a start time Tl that can be considered a first TBTT, the beacon frame 521 on the link 520 is transmitted at a start time T2 that can be considered a second TBTT, and the beacon frame 531 on the link 530 is transmitted at a start time T3 that can be considered a third TBTT. Each time a beacon is transmitted on any of the three links, the wireless device wakes up from PS mode and consumes more power.

[0045] In Figure 5A , at the start time Tl, the TBTT offset between the link 510 and the link 520 is 50 TUs, and at the start time T2, the TBTT offset between the link 520 and the link 530 is 50 TUs. Since the beacon intervals of the three links are 400 TUs, 300 TUs, and 200 TUs, the T total representing the LCM of the beacon intervals of the three links is determined to be 1200 TUs. The time Tl is chosen as the start time T start , the time T4 is chosen as the end time T end , and T4-Tl = 1200 TUs.

[0046] As indicated at 600 in Figure 5AAs shown, during times T1 and T4, link 510 wakes up at time (0, 400, 800) TU, link 520 wakes up at time (50, 350, 650, 950) TU, and link 530 wakes up at time (100, 300, 500, 700, 900, 1100) TU. In this case, the total number of wakeups for all links between start time T1 and end time T4 is Wakeup_times, depending on the TBTT offset between the three links. link1_n There are 13 times in each 1200TU. Therefore, according to the above equation (1), the wake-up ratio WR is calculated in the presence of TBTT offset. beacon It is 1.083.

[0047] like Figure 5B The figure at 550 indicates a case where there is no TBTT offset due to beacon synchronization. Figure 5A In contrast, the start time T1 of link 510, the start time T2 of link 520, and the start time T3 of link 530 are aligned with... Figure 5B The same start time T1 is used in all three links. In some embodiments, links 510, 520, and 530 may be synchronized based on a timing synchronization function (TSF) in a beacon marked by radio hardware. For example, a tri-band device is installed on all three links, and links 510 and 520 may be synchronized first, followed by links 520 and 530. In some embodiments, not all TBTTs of the three links may be aligned and synchronized. For example, the start time of link 520 may be shifted to start time T1, while the start time of link 530 remains unchanged at time T3. As another example, the start time of link 530 may be shifted to start time T1, while the start time of link 520 remains unchanged at time T2.

[0048] exist Figure 5B At start time T1, there is no TBTT offset between links 510, 520, and 530. Since the beacon spacings of these three links are 400TU, 300TU, and 200TU respectively, the T value representing the LCM of the beacon spacing of the three links is... total The value is still set at 1200TU. Time T1 is selected as the start time T. start Select time T4 as the end time T end And T4-T1=1200TU.

[0049] like Figure 5BAs shown, during times T1 and T4, link 510 wakes up at time (0, 400, 800) TU, link 520 wakes up at time (0, 300, 600, 900) TU, and link 530 wakes up at time (0, 300, 600, 900) TU, and link 530 wakes up at time (0, 200, 400, 600, 800, 1000) TU. In this case, since there is no TBTT offset between the three links, the total number of wakeups for all links between start time T1 and end time T4 is Wakeup_times. link1_n There are 8 times in each 1200TU. Therefore, according to the above equation (1), the wake-up ratio WR is calculated in the absence of TBTT offset. beacon It is 0.667. (Compared to...) Figure 5A compared to, Figure 5B The wake-up rate is reduced, thus saving more power for wireless devices.

[0050] In some embodiments, some or all of the beacon intervals used to transmit beacon frames on different links can be adjusted to be the same. For example, such as Figure 5C As indicated by 590, this diagram illustrates a case where there is no TBTT offset and some of the beacon intervals are adjusted to be the same. Figure 5C In this configuration, the beacon spacing on link 520 is increased from 300TU to 400TU, which is the maximum beacon spacing across the three links. Beacon frames 521', 522', 523', and 524' are transmitted on link 520, with a beacon spacing of 400TU on link 520. In this way, the wake-up time of the wireless device can be further reduced.

[0051] exist Figure 5C At start time T1, there is no TBTT offset between links 510, 520, and 530. Since the beacon spacings of these three links are 400TU, 400TU, and 200TU respectively, the T value representing the LCM of the beacon spacing of the three links is... total It was determined to be 400TU. Time T1 was selected as the start time T. start Select time T5 as the end time T end And T5-T1=400TU.

[0052] like Figure 5C As shown, during times T1 and T5, link 510 wakes up at time (0) TU, link 520 wakes up at time (0) TU, and link 530 wakes up at time (0, 200) TU. In this case, since there is no TBTT offset between the three links, the total number of wakeups for all links between start time T1 and end time T5 is Wakeup_times.link1_n In each 400TU, it is 2 times. Therefore, according to the above formula (1), in the case where there is no TBTT offset and the beacon interval of the link 520 is adjusted to be the same as the beacon interval of the link 510, the wake-up ratio WR beacon is 0.5. Compared with Figure 5B ,the wake-up ratio in the link 520 can be further reduced, thereby saving more power for the wireless device. Figure 5C

[0053] In some embodiments, all beacon intervals of all links can be adjusted to be the same. In this case, the total wake-up time Wakeup_times link1_n is 1 in each 400TU, and the wake-up ratio WR beacon is 0.25. In this way, by adjusting part or all of the beacon intervals of the links to be the same, more sleep time can be obtained for the radio of the wireless device, and the power of the wireless device can be further saved.

[0054] Target wake-up time (TWT) is a function that allows an AP to define a specific time or set of times for individual stations to access the medium. The STA and the AP exchange information including the expected duration of activity in order to allow the AP to control the amount of contention and overlap between contending STAs. The use of TWT is negotiated between the AP and the STA, and TWT can be used to reduce energy consumption because a STA using it can go to sleep until its TWT arrives.

[0055] Embodiments of the present disclosure can be used to align TWTs. Figures 6A-6B An example relationship between two sequential TWT SPs is illustrated. As Figure 6A shown in 650, for a single TWT SP 601 on link 1 and a single TWT SP 602 on link 2, there are three different relationships between them. As indicated by 610, the current TWT SP 601 has a containing relationship with the next TWT SP 602. As indicated by 620, the current TWT SP 601 has an intersecting relationship with the next TWT SP 602. As indicated by 630, the current TWT SP 601 has a disjoint relationship with the next TWT SP 602. According to embodiments of the present disclosure, overlapping TWT sessions on different links can be negotiated, and the start times of TWT SPs can be aligned and synchronized, as indicated by 650 in Figure 6B .

[0056] In some embodiments, TWTs on different links can be aligned, and TWT sessions on different links can be transmitted according to the alignment of TWTs. For a single TWT, a broadcast TWT, or a restricted TWT, it can include a TWT wake-up time, a TWT wake-up interval, and a TWT duration. The TWT duration is the maximum service time for each TWT SP in a TWT session. In the case of a single TWT, a broadcast TWT, or a restricted TWT on all links, each link can have TWT parameters for the three TWT modes.

[0057] Figures 7A-7C FIG. 13 illustrates an example of aligning TWT start times of two links of an MLO according to embodiments of the present disclosure. In Figures 7A-7C In the example of FIG. 13, there are two links between an AP MLD (such as the AP MLD 110) and a non-AP MLD (such as the STA MLD 120), which include a first link 1310 and a second link 1320. The TWT parameters TWT parameter(X) The TWT parameters can be defined by Equations (3)-(6) as follows.

[0058] TWT parameter(X) = {TWT start(X | X, n > 0 and X, n e N} (4) interval(X) = {TWT duratio（X) | X, n > 0 and X, n e N} (5)

[0059] where TWT start(X) (X) represents the TWT SP wake-up time of link X, and TWT interval(X (X) represents the TWT SP wake-up interval of link X, and TWT duratio(X (X) represents the TWT SP wake-up duration of link X.

[0060]

[0061] where TWT (X, n) represents the TWT SP start time of link X at period n.

[0062]

[0063] where TWT (X, n) represents the TWT SP end time of link X at period n.

[0064] TWT SPs(X) = {TWT SP(X，n) | X, n > 0 and X, n e N} (6)

[0065] where TWT SPs (X) represents the TWT SP wake-up time of link X, and TWT SP(X，n)TWT SP wake-up time on link X at cycle n.

[0066] To reduce the wake-up time of a wireless device, such as STA MLD 120, embodiments of the present disclosure negotiate overlapping TWT SPs so that the time space of the LCM of the TWT intervals of links X and Y is not an empty set, i.e.,

[0067] In some embodiments, the wake-up ratio WR TWT may be defined as the ratio of the length of TWT wake-up time on all links to the LCM of the TWT intervals of all links in a time unit, such as 100 TU. For example, the wake-up ratio WR TWT may be defined by the following equation (7).

[0068]

[0069] where LCM TWT_interval denotes the LCM of the TWT intervals of all links.

[0070] As indicated in 700 of Figure 7A , which illustrates the case where there is a TWT offset. As shown in Figure 7A , there are two links between the AP MLD 110 and the STA MLD 120, a first link 710 and a second link 720. TWT SPs 711 and 712 are on link 710, the TWT wake-up interval on link 710 is 100 TU, and the TWT wake-up duration on link 710 is 25 TU. TWT SPs 721, 722, 723, and 724 are on link 720, the TWT wake-up interval on link 720 is 50 TU, and the TWT wake-up duration on link 720 is 10 TU.

[0071] Continuing to refer to Figure 7A , the TWT SP 711 on link 710 starts at a start time T1 that can be considered a first TWT, and the TWT SP 721 on link 720 starts at another start time that can be considered a second TWT. During the TWT, the wireless device will wake up from PS mode to receive and / or transmit data. In Figure 7A , the TWT start time offset between link 710 and link 720 is 30 TU at one start time T1. The TWT parameters for link 710 are {T1, 100 TU, 25 TU}, and the TWT parameters for link 720 are {T1 + 30 TU, 50 TU, 10 TU}, and thus the LCM of the TWT intervals of the two links is determined to be 100 TU. The time T1 is chosen as the start time, the time T2 is chosen as the end time, and T2 - T1 = 100 TU.

[0072] As Figure 7A shown in FIG. 7, during time T1 and T2, link 710 wakes up at time [0, 25] TU, and link 720 wakes up at time ([30, 40], [80, 90]) TU. In this case, with the TWT offset between the two links, the total wake-up time length of all links between the start time T1 and the end time T2 is 45 TU in every 100 TU. Therefore, according to the above equation (7), the wake-up ratio WR TWT is calculated to be 0.45 with the TWT offset.

[0073] As Figure 7B indicated in 750 in FIG. 7, which illustrates the case without TWT offset due to TWT synchronization. In contrast to Figure 7A , the start time of TWT on links 710 and 720 is aligned to be the same start time T1 as in Figure 7B . In Figure 7B , the TWT parameters of link 710 are {T1, 100 TU, 25 TU}, and the TWT parameters of link 720 are {T1, 50 TU, 10 TU}, and thus the LCM of TWT intervals of the two links is also determined to be 100 TU. During time T1 and T2, link 710 wakes up at time [0, 25] TU, and link 720 wakes up at time ([0, 10], [50, 60]) TU. In this case, without TWT offset between the two links, the total wake-up time length of all links between the start time T1 and the end time T2 is 35 TU in every 100 TU. Therefore, according to the above equation (7), the wake-up ratio WR TWT is calculated to be 0.35 without TWT offset, which is lower than WR TWT in FIG. 7 with the TWT offset.

[0074] In some embodiments, overlapping TWT SPs can be determined, and TWT sessions on links can be adjusted accordingly. For example, if a first TWT SP on a first link is greater than a second TWT SP on a second link, the TWT session can be moved from the second link to the first link. In IEEE 802.11be, AP MLDs are mandated to support default TID-to-link mapping, so if , TID traffic can go through any link. Therefore, overlapping TWT SPs can be adjusted to save more power.

[0075] As Figure 7Cindicated in 790, which illustrates the case where there is no TWT offset and the adjusted overlapping TWT SPs. The TWT parameters of link 710 are {T1, 100 TU, 25 TU}, and the TWT parameters of link 720 change from {T1, 50 TU, 10 TU} to {T1+50, 100 TU, 10 TU}. In this case, the total wake-up time length between the start time T1 and the end time T2 for all links is still 35 TU in every 100 TU. Therefore, according to the above equation (7), the wake-up ratio WR TWT is 0.35. Although Figure 7C the wake-up ratio WR TWT in 790 is the same as Figure 7B in 790, it reduces the start time on link 720 in 790 and saves more power on link 720. Figure 7C

[0076] It should be appreciated that although two links are shown in 790 based on MLO, the MLO can have more links for TWT between the AP MLD 110 and the STA MLD 120. For example, in the case where three links are established between the AP MLD and the STA MLD, the TWTs of the three links can be aligned at the same start time. Figures 7A-7C

[0077] According to embodiments of the present disclosure, aligning the TBTT and adjusting the beacon interval(s) and the TWT parameter(s) can improve the power saving of the wireless device, and the high beacon interval and the TWT wake-up interval can save more power.

[0078] Figure 8 An example AP MLD 110 according to embodiments of the present disclosure is illustrated. As shown in 790, the AP MLD 110 includes at least one processor 810 and a memory 820 coupled to the at least one processor 810. The memory 820 stores instructions 822, 824, 826, and 828 to cause the processor 810 to perform actions according to embodiments of the present disclosure. Figure 8 As shown in 790, the memory 820 stores instructions 822 to setup a first link and a second link between an access point (AP) and a wireless device based on multi-link operation (MLO), and instructions 824 to obtain a first target beacon transmission time (TBTT) for the first link and a second TBTT for the second link. As shown in 790, the memory 820 stores instructions 826 to align the first TBTT and the second TBTT, and instructions 828 to adjust a beacon interval and a TWT parameter based on the aligning the first TBTT and the second TBTT.

[0079] Figure 8 Figure 8 ​​​​As shown in FIG. 8B, the memory 820 further stores instructions to align the first TBTT and the second TBTT at the start time, and to transmit the beacon frames on the first link and the second link according to the alignment of the first TBTT and the second TBTT.

[0080] In some embodiments, the instructions 826 are further to select a target time for aligning the first TBTT and the second TBTT, to determine the target time as the start time for transmitting the beacon frames on the first link, and to determine the target time as the start time for transmitting the beacon frames on the second link.

[0081] In some embodiments, the memory 820 further stores instructions to obtain a first beacon interval for transmitting the beacon frames on the first link, and to obtain a second beacon interval for transmitting the beacon frames on the second link. The memory 820 further stores instructions to determine whether the first beacon interval is different from the second beacon interval, and to adjust the second beacon interval of the second link to be the same as the first beacon interval of the first link in response to determining that the first beacon interval is different from the second beacon interval.

[0082] In some embodiments, the instructions 826 are further to obtain a third TBTT of a third link between the AP and the wireless device, and to align the first TBTT, the second TBTT, and the third TBTT at the start time.

[0083] In some embodiments, the memory 820 further stores instructions to obtain a third beacon interval for transmitting the beacon frames on the third link, to determine whether the first beacon interval is different from the third beacon interval. The memory 820 further stores instructions to adjust the third beacon interval of the third link to be the same as the first beacon interval of the first link in response to determining that the first beacon interval is different from the third beacon interval.

[0084] In some embodiments, the wireless device enters a power save mode after completing the transmission of the beacon frames on the first link and the second link.

[0085] In some embodiments, the memory 820 further stores instructions to obtain a target wake time (TWT) of the first link and a second TWT of the second link, to align the first TWT and the second TWT at the start time, and to transmit a TWT session on the first link and the second link according to the alignment of the first TWT and the second TWT.

[0086] In some embodiments, the memory 820 further stores instructions to obtain a first TWT service period of the first link and a second TWT service period of the second link, to determine an overlapping TWT service period based on the first TWT service period and the second TWT service period, and to adjust TWT sessions on the first link and the second link according to the overlapping TWT service period.

[0087] In some embodiments, the memory 820 further stores instructions to determine whether the first TWT service period is greater than the second TWT service period. The memory 820 further stores instructions to, in response to determining that the first TWT service period is greater than the second TWT service period, move a TWT session corresponding to the second TWT service period from the second link to the first link, and transmit the moved TWT session using the first link.

[0088] In some embodiments, a non-transitory computer-readable medium is disclosed. The non-transitory computer-readable medium includes instructions stored thereon that, when executed by an access point (AP), cause the AP to establish a first link and a second link between the access point (AP) and a wireless device based on multi-link operation (MLO), obtain a first target beacon transmit time (TBTT) for the first link and a second TBTT for the second link. The instructions, when executed by the AP, further cause the AP to align the first TBTT and the second TBTT at a start time, and transmit a beacon frame on the first link and the second link according to the alignment of the first TBTT and the second TBTT.

[0089] Program code or instructions for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. These program codes or instructions can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes are executed by the processor or controller to produce the functions / operations specified in the flowcharts and / or block diagrams. The program code or instructions can be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0090] In the context of the present disclosure, a machine-readable medium can be any tangible medium that can contain or store program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable storage media can include, without limitation, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine-readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0091] Moreover, while operations may be depicted in the drawings in a particular order, this should not be understood as requiring such order, nor that all illustrated operations be performed, to implement such operations, and that a described implementation can include frequent counter to those operations, and / or in parallel, and / or at different times. In some cases, described operations can be omitted. In other cases, additional operations can be performed not described. Some examples can be practiced without the use of one or more features or without the use of all features described. Practice of associated examples can be by a single integrated circuit or multiple interconnected integrated circuits, as appropriate. Reference to first, second, etc., can be understood as a non- limiting identification of important points of an illustration, as opposed to an absolute, serial characterization of matters described. It should be understood that many implementation examples can be manifested other than in hardware and / or software, e.g., in fabric, and that can be provided software, such as provided by one or more processors of a computer-based system or other system designed for carrying out the processes described herein. Particularly, a variety of hardware and software systems can be used to implement the example flash memory controller and method steps described in this patent. Whether software or hardware is used to implement the examples is dependent on the specific application and design constraints imposed on the far example. Those skilled in the art can implement the described examples in varying ways for each application. Furthermore, it should be emphasized that a variety of computer-based systems can be used to implement the example flash memory controller and method steps described in this patent. It is therefore intended that the embodiments recited in this patent include all such variations and modifications. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the examples, but one of ordinary skill in the art can recognize that many further combinations and permutations of various example components are possible. Accordingly, it is intended to embrace all such variations and modifications as can come within the scope of the appended claims and their equivalents.

[0092] In the foregoing detailed description of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration examples in which the disclosure can be practiced. These examples are described in sufficient detail to enable those skilled in the art to practice the examples, and it is to be understood that other examples can be utilized and that process, electrical, and / or structural changes can be made

Claims

1. A method of adjusting beacon intervals, comprising: establishing a first link and a second link between an access point (AP) and a wireless device based on multi-link operation (MLO); obtaining a first target beacon transmit time (TBTT) for the first link and a second TBTT for the second link; aligning the first TBTT and the second TBTT at a start time; and transmitting beacon frames on the first link and the second link in accordance with the alignment of the first TBTT and the second TBTT; obtaining a first beacon interval for transmitting beacon frames on the first link; obtaining a second beacon interval for transmitting beacon frames on the second link; determining whether the first beacon interval is different from the second beacon interval; and in response to determining that the first beacon interval is different from the second beacon interval, adjusting the second beacon interval of the second link to be the same as the first beacon interval of the first link.

2. The method of claim 1, wherein aligning the first TBTT and the second TBTT at a start time comprises: selecting a target time for aligning the first TBTT and the second TBTT; determining the target time as the start time for transmitting beacon frames on the first link; and determining the target time as the start time for transmitting beacon frames on the second link.

3. The method of claim 1, wherein aligning the first TBTT and the second TBTT at a start time comprises: obtaining a third TBTT for a third link between the AP and the wireless device; and aligning the first TBTT, the second TBTT, and the third TBTT at the start time.

4. The method of claim 3, further comprising: obtaining a third beacon interval for transmitting beacon frames on the third link; determining whether the first beacon interval is different from the third beacon interval; and in response to determining that the first beacon interval is different from the third beacon interval, adjusting the third beacon interval of the third link to be the same as the first beacon interval of the first link.

5. The method of claim 1, wherein the wireless device enters into a power save mode after completing the transmission of beacon frames on both the first link and the second link.

6. The method of claim 1, further comprising: obtaining a target wake time (TWT) for the first link and a second TWT for the second link; aligning the first TWT and the second TWT at a start time; and transmitting TWT sessions on the first link and the second link in accordance with the alignment of the first TWT and the second TWT.

7. The method of claim 6, further comprising: obtaining a first TWT service period for the first link and a second TWT service period for the second link; determining an overlapping TWT service period based on the first TWT service period and the second TWT service period; and transmitting the TWT sessions on the first link and the second link in accordance with the overlapping TWT service period. ​ ​ ​ ​ ​ adjust the TWT session on the first link and the second link according to the overlapping TWT service periods.

8. The method of claim 7, wherein adjusting the TWT session on the first link and the second link according to the overlapping TWT service periods comprises: determining whether the first TWT service period is greater than the second TWT service period; in response to determining that the first TWT service period is greater than the second TWT service period, moving a TWT session corresponding to the second TWT service period from the second link to the first link; and using the first link to transmit the moved TWT session.

9. An access point (AP), comprising: at least one processor; and a memory coupled to the at least one processor, the memory storing instructions that cause the at least one processor to perform actions comprising: establishing a first link and a second link between the AP and a wireless device based on a multi-link operation (MLO); obtaining a first target beacon transmit time (TBTT) for the first link and a second TBTT for the second link; aligning the first TBTT and the second TBTT at a start time; and transmitting a beacon frame on the first link and the second link according to the alignment of the first TBTT and the second TBTT; obtaining a first beacon interval for transmitting a beacon frame on the first link; obtaining a second beacon interval for transmitting a beacon frame on the second link; determining whether the first beacon interval is different from the second beacon interval; and in response to determining that the first beacon interval is different from the second beacon interval, adjusting the second beacon interval for the second link to be the same as the first beacon interval for the first link.

10. The AP of claim 9, wherein aligning the first TBTT and the second TBTT at a start time comprises: selecting a target time for aligning the first TBTT and the second TBTT; determining the target time as the start time for transmitting a beacon frame on the first link; and determining the target time as the start time for transmitting a beacon frame on the second link.

11. The AP of claim 9, wherein aligning the first TBTT and the second TBTT at a start time comprises: obtaining a third TBTT for a third link between the AP and the wireless device; and aligning the first TBTT, the second TBTT, and the third TBTT at the start time.

12. The AP of claim 11, the actions further comprising: obtaining a third beacon interval for transmitting a beacon frame on the third link; determining whether the first beacon interval is different from the third beacon interval; and in response to determining that the first beacon interval is different from the third beacon interval, adjusting the third beacon interval for the third link to be the same as the first beacon interval for the first link. ​ ​ ​ ​ ​ ​ 13. The AP of claim 9, wherein the wireless device enters into a power save mode after completing the sending of beacon frames on both the first link and the second link.

14. The AP of claim 9, the actions further comprising: obtaining a target wake time (TWT) of the first link and a second TWT of the second link; aligning the first TWT and the second TWT at a start time; and sending a TWT session on the first link and the second link in accordance with the alignment of the first TWT and the second TWT.

15. The AP of claim 14, the actions further comprising: obtaining a first TWT service period of the first link and a second TWT service period of the second link; determining an overlapping TWT service period based on the first TWT service period and the second TWT service period; and adjusting the TWT session on the first link and the second link in accordance with the overlapping TWT service period.

16. The AP of claim 15, wherein adjusting the TWT session on the first link and the second link in accordance with the overlapping TWT service period comprises: determining whether the first TWT service period is greater than the second TWT service period; in response to determining that the first TWT service period is greater than the second TWT service period, moving a TWT session corresponding to the second TWT service period from the second link to the first link; and sending the moved TWT session using the first link.

17. A non-transitory computer-readable medium comprising instructions stored thereon that, when executed by an access point (AP), cause the AP to: establish a first link and a second link between the AP and a wireless device based on multi-link operation (MLO); obtain a first target beacon transmit time (TBTT) of the first link and a second TBTT of the second link; align the first TBTT and the second TBTT at a start time; and send a beacon frame on the first link and the second link in accordance with the alignment of the first TBTT and the second TBTT; obtain a first beacon interval for sending a beacon frame on the first link; obtain a second beacon interval for sending a beacon frame on the second link; determine whether the first beacon interval is different from the second beacon interval; and in response to determining that the first beacon interval is different from the second beacon interval, adjust the second beacon interval of the second link to be the same as the first beacon interval of the first link.

18. The non-transitory computer-readable medium of claim 17, wherein the instructions, when executed by an AP, further cause the AP to: select a target time for aligning the first TBTT and the second TBTT; determine the target time as the start time for sending a beacon frame on the first link; and determine the target time as the start time for sending a beacon frame on the second link. ​ ​ ​ ​ ​ ​

Images