This disclosure relates generally to wireless communication systems, and more particularly to, for example, but not limited to, multi-AP coordination in wireless communication systems.
Wireless local area network (WLAN) technology has evolved toward increasing data rates and continues its growth in various markets such as home, enterprise and hotspots over the years since the late 1990s. WLAN allows devices to access the internet in the 2.4 GHZ, 5 GHZ, 6 GHz or 60 GHz frequency bands. WLANs are based on the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standards. IEEE 802.11 family of standards aims to increase speed and reliability and to extend the operating range of wireless networks.
WLAN devices are increasingly required to support a variety of delay-sensitive applications or real-time applications such as augmented reality (AR), robotics, artificial intelligence (AI), cloud computing, and unmanned vehicles. To implement extremely low latency and extremely high throughput required by such applications, multi-link operation (MLO) has been suggested for the WLAN. The WLAN is formed within a limited area such as a home, school, apartment, or office building by WLAN devices. Each WLAN device may have one or more stations (STAs) such as the access point (AP) STA and the non-access-point (non-AP) STA.
The MLO may enable a non-AP multi-link device (MLD) to set up multiple links with an AP MLD. Each of multiple links may enable channel access and frame exchanges between the non-AP MLD and the AP MLD independently, which may reduce latency and increase throughput.
The description set forth in the background section should not be assumed to be prior art merely because it is set forth in the background section. The background section may describe aspects or embodiments of the present disclosure.
An aspect of the present disclosure provides a first access point (AP) in a wireless network. The first AP device comprises a memory and a processor coupled to the memory. The processor configured to cause: establishing a multi-AP coordination with a second AP, wherein the first AP and the second AP are members of a target wake time (TWT) coordination AP set and the first AP shares a TWT schedule or a TWT agreement with a second AP; generating a frame indicating a change to one or more TWT parameters of the TWT schedule or the TWT agreement; and transmitting the frame to the second AP.
In some embodiments, the frame indicates a time when the change to the one or more TWT parameters takes effect.
In some embodiments, the processor is further configured to cause advertising an updated TWT schedule to one or more non-AP stations that are associated with the first AP, the updated TWT schedule including the change to the one or more TWT parameters.
In some embodiments, the processor is further configured to cause, in response to transmitting the frame, receiving a response frame from the second AP. The response frame indicates a rejection, an acceptance, or alternative suggestion to the change.
In some embodiments, the time is indicated in a TWT persistence parameter of a TWT element included in the frame.
In some embodiments, the time is associated with a number of beacon intervals during one or more TWT service periods of the TWT schedule or the TWT agreement.
In some embodiments, the second AP controls one or more APs that are members of the TWT coordination AP set.
In some embodiments, the frame comprises a TWT element corresponding to the TWT schedule or the TWT agreement for which the one or more TWT parameters are to be changed.
In some embodiments, the processor is further configured to cause, in response to receiving the response frame indicating the acceptance or the alternate suggestion to the change from the second AP, transmitting another frame indicating the change or an alternative change to the one or more TWT parameters of the TWT schedule or the TWT agreement.
In some embodiments, the advertising the updated TWT schedule comprises advertising the time when the change to the one or more TWT parameters take effect.
An aspect of the present disclosure provides a first access point (AP) in a wireless network. The first AP device comprises a memory and a processor coupled to the memory. The processor configured to cause: establishing a multi-AP coordination with a second AP, wherein the first AP and the second AP are members of a target wake time (TWT) coordination AP set and the second AP shares a TWT schedule or a TWT agreement with the first AP; receiving a frame indicating a change to one or more TWT parameters for the TWT schedule or the TWT agreement; and in response to receiving the frame, transmitting a response frame indicating a rejection, an acceptance, or alternative suggestion to the change.
In some embodiments, the frame indicates a time when the change to the one or more TWT parameters takes effect.
In some embodiments, when the response frame indicating the acceptance to the change is transmitted, the processor is further configured to cause advertising an updated TWT schedule to one or more non-AP stations that are associated with the first AP, the updated TWT schedule including the change to the one or more TWT parameters.
In some embodiments, the response frame indicating the rejection to the change is transmitted, the processor is further configured to cause abstaining advertising the TWT schedule to one or more non-AP stations that are associated with the first AP.
In some embodiments, the time is indicated in a TWT persistence parameter of a TWT element included in the frame.
In some embodiments, the time is associated with a number of beacon intervals during one or more TWT service periods of the TWT schedule or the TWT agreement.
In some embodiments, the frame comprises a TWT element corresponding to the TWT schedule or the TWT agreement for which the one or more TWT parameters are to be changed.
In some embodiments, the frame is received from the second AP and the response frame is transmitted to the second AP.
In some embodiments, the frame is received from a controlling AP that controls one or more APs that are members of the TWT coordination AP set, and the response frame is transmitted to the controlling AP.
In some embodiments, the advertising the updated TWT schedule comprises advertising the time when the change to the one or more TWT parameters take effect.
In one or more implementations, not all of the depicted components in each figure may be required, and one or more implementations may include additional components not shown in a figure. Variations in the arrangement and type of the components may be made without departing from the scope of the subject disclosure. Additional components, different components, or fewer components may be utilized within the scope of the subject disclosure.
The detailed description set forth below, in connection with the appended drawings, is intended as a description of various implementations and is not intended to represent the only implementations in which the subject technology may be practiced. Rather, the detailed description includes specific details for the purpose of providing a thorough understanding of the inventive subject matter. As those skilled in the art would realize, the described implementations may be modified in various ways, all without departing from the scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements.
The following description is directed to certain implementations for the purpose of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The examples in this disclosure are based on WLAN communication according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, including IEEE 802.11be standard and any future amendments to the IEEE 802.11 standard. However, the described embodiments may be implemented in any device, system or network that is capable of transmitting and receiving radio frequency (RF) signals according to the IEEE 802.11 standard, the Bluetooth standard, Global System for Mobile communications (GSM), GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA), Evolution Data Optimized (EV-DO), 1×EV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High Speed Packet Access (HSPA+), Long Term Evolution (LTE), 5G NR (New Radio), AMPS, or other known signals that are used to communicate within a wireless, cellular or internet of things (IoT) network, such as a system utilizing 3G, 4G, 5G, 6G, or further implementations thereof, technology.
Depending on the network type, other well-known terms may be used instead of “access point” or “AP,” such as “router” or “gateway.” For the sake of convenience, the term “AP” is used in this disclosure to refer to network infrastructure components that provide wireless access to remote terminals. In WLAN, given that the AP also contends for the wireless channel, the AP may also be referred to as a STA. Also, depending on the network type, other well-known terms may be used instead of “station” or “STA,” such as “mobile station,” “subscriber station,” “remote terminal,” “user equipment,” “wireless terminal,” or “user device.” For the sake of convenience, the terms “station” and “STA” are used in this disclosure to refer to remote wireless equipment that wirelessly accesses an AP or contends for a wireless channel in a WLAN, whether the STA is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer, AP, media player, stationary sensor, television, etc.).
Multi-link operation (MLO) is a key feature that is currently being developed by the standards body for next generation extremely high throughput (EHT) Wi-Fi systems in IEEE 802.11be. The Wi-Fi devices that support MLO are referred to as multi-link devices (MLD). With MLO, it is possible for a non-AP MLD to discover, authenticate, associate, and set up multiple links with an AP MLD. Channel access and frame exchange is possible on each link between the AP MLD and non-AP MLD.
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The APs 101 and 103 communicate with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network. The AP 101 provides wireless access to the network 130 for a plurality of stations (STAs) 111-114 with a coverage are 120 of the AP 101. The APs 101 and 103 may communicate with each other and with the STAs using Wi-Fi or other WLAN communication techniques.
Depending on the network type, other well-known terms may be used instead of “access point” or “AP,” such as “router” or “gateway.” For the sake of convenience, the term “AP” is used in this disclosure to refer to network infrastructure components that provide wireless access to remote terminals. In WLAN, given that the AP also contends for the wireless channel, the AP may also be referred to as a STA. Also, depending on the network type, other well-known terms may be used instead of “station” or “STA,” such as “mobile station,” “subscriber station,” “remote terminal,” “user equipment,” “wireless terminal,” or “user device.” For the sake of convenience, the terms “station” and “STA” are used in this disclosure to refer to remote wireless equipment that wirelessly accesses an AP or contends for a wireless channel in a WLAN, whether the STA is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer, AP, media player, stationary sensor, television, etc.).
In
As described in more detail below, one or more of the APs may include circuitry and/or programming for management of MU-MIMO and OFDMA channel sounding in WLANs. Although
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The TX processing circuitry 214 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor 224. The TX processing circuitry 214 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers 209a-209n receive the outgoing processed baseband or IF signals from the TX processing circuitry 214 and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 204a-204n.
The controller/processor 224 can include one or more processors or other processing devices that control the overall operation of the AP 101. For example, the controller/processor 224 could control the reception of uplink signals and the transmission of downlink signals by the RF transceivers 209a-209n, the RX processing circuitry 219, and the TX processing circuitry 214 in accordance with well-known principles. The controller/processor 224 could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor 224 could support beam forming or directional routing operations in which outgoing signals from multiple antennas 204a-204n are weighted differently to effectively steer the outgoing signals in a desired direction. The controller/processor 224 could also support OFDMA operations in which outgoing signals are assigned to different subsets of subcarriers for different recipients (e.g., different STAs 111-114). Any of a wide variety of other functions could be supported in the AP 101 by the controller/processor 224 including a combination of DL MU-MIMO and OFDMA in the same transmit opportunity. In some embodiments, the controller/processor 224 may include at least one microprocessor or microcontroller. The controller/processor 224 is also capable of executing programs and other processes resident in the memory 229, such as an OS. The controller/processor 224 can move data into or out of the memory 229 as required by an executing process.
The controller/processor 224 is also coupled to the backhaul or network interface 234. The backhaul or network interface 234 allows the AP 101 to communicate with other devices or systems over a backhaul connection or over a network. The interface 234 could support communications over any suitable wired or wireless connection(s). For example, the interface 234 could allow the AP 101 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 234 may include any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver. The memory 229 is coupled to the controller/processor 224. Part of the memory 229 could include a RAM, and another part of the memory 229 could include a Flash memory or other ROM.
As described in more detail below, the AP 101 may include circuitry and/or programming for management of channel sounding procedures in WLANs. Although
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The RF transceiver 210 receives, from the antenna(s) 205, an incoming RF signal transmitted by an AP of the network 100. The RF transceiver 210 down-converts the incoming RF signal to generate an IF or baseband signal. The IF or baseband signal is sent to the RX processing circuitry 225, which generates a processed baseband signal by filtering, decoding, and/or digitizing the baseband or IF signal. The RX processing circuitry 225 transmits the processed baseband signal to the speaker 230 (such as for voice data) or to the controller/processor 240 for further processing (such as for web browsing data).
The TX processing circuitry 215 receives analog or digital voice data from the microphone 220 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the controller/processor 240. The TX processing circuitry 215 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 210 receives the outgoing processed baseband or IF signal from the TX processing circuitry 215 and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) 205.
The controller/processor 240 can include one or more processors and execute the basic OS program 261 stored in the memory 260 in order to control the overall operation of the STA 111. In one such operation, the controller/processor 240 controls the reception of downlink signals and the transmission of uplink signals by the RF transceiver 210, the RX processing circuitry 225, and the TX processing circuitry 215 in accordance with well-known principles. The controller/processor 240 can also include processing circuitry configured to provide management of channel sounding procedures in WLANs. In some embodiments, the controller/processor 240 may include at least one microprocessor or microcontroller.
The controller/processor 240 is also capable of executing other processes and programs resident in the memory 260, such as operations for management of channel sounding procedures in WLANs. The controller/processor 240 can move data into or out of the memory 260 as required by an executing process. In some embodiments, the controller/processor 240 is configured to execute a plurality of applications 262, such as applications for channel sounding, including feedback computation based on a received null data packet announcement (NDPA) and null data packet (NDP) and transmitting the beamforming feedback report in response to a trigger frame (TF). The controller/processor 240 can operate the plurality of applications 262 based on the OS program 261 or in response to a signal received from an AP. The controller/processor 240 is also coupled to the I/O interface 245, which provides STA 111 with the ability to connect to other devices such as laptop computers and handheld computers. The I/O interface 245 is the communication path between these accessories and the main controller/processor 240.
The controller/processor 240 is also coupled to the input 250 (such as touchscreen) and the display 255. The operator of the STA 111 can use the input 250 to enter data into the STA 111. The display 255 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites. The memory 260 is coupled to the controller/processor 240. Part of the memory 260 could include a random access memory (RAM), and another part of the memory 260 could include a Flash memory or other read-only memory (ROM).
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The non-AP MLD 320 may include a plurality of affiliated STAs, for example, including STA 1, STA 2, and STA 3. Each affiliated STA may include a PHY interface to the wireless medium (Link 1, Link 2, or Link 3). The non-AP MLD 320 may include a single MAC SAP 328 through which the affiliated STAs of the non-AP MLD 320 communicate with a higher layer (Layer 3 or network layer). Each affiliated STA of the non-AP MLD 320 may have a MAC address (lower MAC address) different from any other affiliated STAs of the non-AP MLD 320. The non-AP MLD 320 may have a MLD MAC address (upper MAC address) and the affiliated STAs share the single MAC SAP 328 to Layer 3. Thus, the affiliated STAs share a single IP address, and Layer 3 recognizes the non-AP MLD 320 by assigning the single IP address.
The AP MLD 310 and the non-AP MLD 320 may set up multiple links between their affiliate APs and STAs. In this example, the AP 1 and the STA 1 may set up Link 1 which operates in 2.4 GHz band. Similarly, the AP 2 and the STA 2 may set up Link 2 which operates in 5 GHZ band, and the AP 3 and the STA 3 may set up Link 3 which operates in 6 GHz band. Each link may enable channel access and frame exchange between the AP MLD 310 and the non-AP MLD 320 independently, which may increase date throughput and reduce latency. Upon associating with an AP MLD on a set of links (setup links), each non-AP device is assigned a unique association identifier (AID).
The following documents are hereby incorporated by reference in their entirety into the present disclosure as if fully set forth herein: i) IEEE 802.11-2020, “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications” and ii) IEEE P802.11be/D3.0, “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.”
Target wake time (TWT) operation is a feature of power management in WLAN networks. The TWT operation enables an AP to manage activity in the basic service set (BSS) to minimize contention between STAs and reduce required wake times for STAs during the TWT operation. It may be achieved by allocating STAs to operate at non-overlapping times or frequencies and perform frame exchange sequences in pre-scheduled service periods. In the TWT operation, a STA can wake up at pre-scheduled times that have been negotiated with an AP or another STA in the BSS. The STA does not need to be aware of TWT parameter values of other STAs within the BSS or of STAs in other BSSs. The STA does not need to be aware that a TWT service period (SP) is used to exchange frames with other STAs. Frames transmitted during the TWT SP can employ any PPDU (physical layer protocol data unit) format supported by the pair of STAs that have established the corresponding TWT agreement, including, but not limited to, HE MU (high efficiency multi-user) PPDU, HE TB (high efficiency trigger based) PPDU.
IEEE 802.11 standard describes two types of TWT operations: individual TWT operation and broadcast TWT operation. In the individual TWT operation, an individual TWT agreement can be established between two STAs or between a STA and an AP. The negotiation for the individual TWT operation may occur between two STAs or between a STA and an AP on an individual basis. An AP may have TWT agreements with multiple STAs. Any changes in the TWT agreement between the AP and one STA do not affect the TWT agreement between the AP and other STAs.
On the other hand, the broadcast TWT operates in a membership-based approach. In broadcast TWT operation, an AP can set up a shared TWT session for a group of STAs. The AP is typically the controller of the broadcast TWT schedule. The non-AP STAs in the BSS can request membership in the broadcast TWT schedule, or the AP can send unsolicited response to a STA to make the STA a member of the broadcast TWT schedule that the AP maintains in the BSS. The AP may advertise and maintain multiple broadcast TWT schedules in the BSS. When a change is made to any broadcast TWT schedules in the BSS, it may affect all or some of STAs that are members of the corresponding broadcast TWT schedule.
As discussed above, the multi-link operation (MLO) is a key feature for next generation WLAN. Devices that support the MLO may be referred to as multi-link devices (MLD). With MLO, it is possible for a non-AP MLD to discover, authenticate, associate, and set up multiple links with an AP MLD. Channel access and frame exchange is possible on each link between the AP MLD and non-AP MLD.
TWT enhancements for multi-link devices have recently been discussed in various ways. For example, for individual TWT agreements between two MLDs, a STA affiliated with an MLD, which is a TWT requesting STA, may indicate one or more links that are requested for setting up TWT agreements in the Link ID bitmap subfield of a TWT element in the TWT request. If only one link is indicated in the Link ID bitmap subfield of the TWT element, a single TWT agreement is requested for the STA affiliated with the same MLD, which is operating on the indicated link. A Target Wake Time field of the TWT element may be in reference to the TSF time of the link indicated by the TWT element. Then, a TWT responding STA affiliated with a peer MLD that receives the TWT request including the Link ID bitmap subfield responds with a TWT response indicating one or more links in the Link ID bitmap subfield in the TWT element. The one or more links in the TWT element carried in the TWT response may be the same as the one or more links in the TWT element carried in the TWT response.
Restricted TWT (R-TWT) operation is another important feature for the next generation WLAN. The R-TWT operation provides better support for latency sensitive applications. For instance, traffic in real time applications has stringent requirements in terms of latency and jitter along with certain reliability constraints. Such traffic may be referred to as latency sensitive traffic in this disclosure. The R-TWT operation may offer a protected service period (SP) for R-TWT member STAs by sending Quiet elements to non-member STAs in the BSS in the R-TWT schedule. In some implementations, a quiet interval of the Quiet element overlaps with the initial portion of the R-TWT SP. Therefore, it may provide greater channel access opportunities to R-TWT member STAs than non-member STAs, thereby improving the flow of latency sensitive traffic.
Interference from one BSS may often lead to performance issues for STAs and APs in neighboring BSSs. This interference may result in overall throughput degradation in the network. The Overlapping BSS (OBSS) interference may also increase the overall latency since it takes more time to access the channel due to the interference occupying the channel. If a STA in a BSS has latency-sensitive traffic, this delay in channel access may significantly impede the performance of the STA's latency-sensitive applications. TWT-based multi-AP coordination can be an important feature for the next generation WLAN.
In an embodiment, a first AP may coordinate with a second AP in the vicinity in order to coordinate with the AP's individual TWT agreement, a broadcast TWT schedule, or R-TWT schedule. The coordination mechanism may take different formats based on the architecture of the C-TWT negotiation.
In
In an embodiment, negotiations between APs for TWT based multi-AP coordination may be controlled by a controller, for example, a TWT central controller.
In
In some embodiments, a first AP has successfully established TWT-based multi-AP coordination with a second AP in a multi-AP coordination set for a TWT schedule or a TWT agreement identified by a first TWT parameter set within a TWT element. The first AP may be a TWT sharing AP and the second AP may be a TWT shard AP. In this disclosure, a TWT sharing AP refers to an AP that has a TWT schedule in its BSS and initiates a TWT coordination request to a neighboring AP in the multi-AP coordination set. If an AP has established a TWT schedule in its BSS and solicits assistance from the neighboring AP to protect channel access during its TWT SP, the AP is designated as the TWT sharing AP. On the other hand, a TWT shared AP refers to an AP that receives the TWT coordination request from another AP.
In this scenario, when the first AP intends to make any changes to TWT parameters to the TWT schedule or the TWT agreement, it may result in the creation of a second TWT parameter set or an updated TWT parameter set. However, the response of both the first AP and the second AP to such changes or updates to the TWT parameters remains unclear and undefined. Therefore, a procedure and the framework are needed to manage changes in TWT parameters associated with the TWT schedule or the TWT agreement where multi-AP coordination has been established among two or more APs.
The present disclosure provides a mechanism and a procedure for updating TWT parameters associated with a TWT schedule or a TWT agreement where multi-AP coordination has been established among two or more APs.
In some embodiments, a first AP has successfully established TWT-based multi-AP coordination with a second AP in multi-AP coordination set for a TWT schedule or a TWT agreement identified by a first TWT parameter set. The first AP may be a TWT sharing AP and the second AP may be a TWT shard AP. In this scenario, when the first AP intends to make any changes or updates to parameters to the TWT schedule or the TWT agreement, it may result in the creation of a second TWT parameter set. The first AP will notify the second AP about the impending changes before the first AP makes the changes to the TWT parameters. In some implementations, this notification can be made by sending a frame to the second AP. The frame can be referred to as a coordinated TWT (C-TWT) parameter update notification frame. The frame may include identification of the TWT schedule for which parameters are to be changed. The frame may also include information associated with the changes. The frame can be an individually-addressed frame, a multi-cast frame, or a broadcast frame. A possible format of the C-TWT parameter update notification frame is provided in the following Table 1.
Referring to Table 1, the C-TWT parameter update notification frame includes a category field, an unprotected SIG action field, a dialog token field, and one or more TWT elements.
The category field may indicate a category to which the C-TWT parameter update notification frame belongs. The unprotected SIG action field differentiates unprotected SIG action frame formats within predetermined unprotected SIG category. The dialog token field may be set to a nonzero value chosen by the AP sending the C-TWT parameter update notification frame to identify the notification/response transaction.
The TWT element in the C-TWT parameter update notification frame may correspond to the TWT schedule or the TWT agreement for which parameters are pending changes or updates. For a broadcast TWT schedule, the Broadcast TWT ID of the updated TWT parameter set may be the same as the Broadcast TWT ID of the previous TWT parameter set which has been established between two or more APs. For an individual TWT agreement, the TWT Flow Identifier of the updated TWT parameter set may be the same as the TWT Flower Identifier of the previous TWT parameter set which has been established between two APs. Other TWT parameters in the TWT element may correspond to updated TWT parameters. An example of the TWT element will be provided later, with reference to
The process 600 may begin in operation 601. In operation 601, a first AP establishes a TWT-based multi-AP coordination with a second AP in a multi-AP coordination set for a TWT schedule or a TWT agreement identified by a first TWT parameter set.
In operation 603, the first AP intends to change or update TWT parameters of the TWT schedule or the TWT agreement. Furthermore, the first AP may intend to replace the first TWT parameter set with a second TWT parameter set.
In operation 605, the first AP sends a C-TWT parameter update notification frame to the second AP to notify the second AP of impending changes or updates to the TWT parameters.
In operation 607, the first AP starts advertising an updated TWT schedule in a frame carrying an TWT element including the second TWT parameter set in its BSS, indicating a time when the updated TWT schedule and the updated TWT parameter takes effect. The updated TWT schedule and the updated TWT parameter will take effect from the time indicated in the second TWT parameter set. In some embodiments, the time can be indicated by the TWT Persistence subfield of the TWT element.
The process 650 may begin in operation 651. In operation 651, the second AP establishes a TWT-based multi-AP coordination with the first AP in the multi-AP coordination set for the TWT schedule or the TWT agreement identified by the first TWT parameter set.
In operation 653, the second AP receives the C-TWT parameter update notification frame from the first AP notifying the second AP of impending changes or updates to the TWT parameters.
In operation 655, in response to receiving the C-TWT parameter update notification frame, the second AP sends a C-TWT parameter update response frame to the first AP indicating whether the second AP accepts the changes, rejects the changes, or suggest an alternative changes to the TWT parameters of the TWT schedule or the TWT agreement. In some embodiments, a possible format of the C-TWT parameter update response frame is provided in the following Table
Referring to Table 2, the C-TWT parameter update response frame includes a category field, an unprotected SIG action field, a dialog token field, and one or more TWT elements.
The category field may indicate a category to which the C-TWT parameter update response frame belongs. The unprotected SIG action field differentiates unprotected SIG action frame formats within predetermined unprotected SIG category. The dialog token field may be set to a nonzero value chosen by the AP sending the C-TWT parameter update response frame to identify the notification/response transaction.
The TWT element in the C-TWT parameter update response frame may correspond to the TWT schedule or the TWT agreement for which parameters are pending changes or updates. For a broadcast TWT schedule, the Broadcast TWT ID of the updated TWT parameter set may be the same as the Broadcast TWT ID of the previous TWT parameter set which has been established between two or more APs. For an individual TWT agreement, the TWT Flow Identifier of the updated TWT parameter set may be the same as the TWT Flower Identifier of the previous TWT parameter set which has been established between two APs. Other TWT parameters in the TWT element may correspond to updated TWT parameters.
In
In response to the C-TWT parameter update notification frame, AP 2 rejects the update on the TWT parameter of the TWT schedule or the TWT agreement by sending a C-TWT parameter update response frame indicating the reject of the update to AP 1. AP 3 may suggest alternative update on the TWT parameter of the TWT schedule or the TWT agreement by sending a C-TWT parameter update response frame indicating alternative update to AP 1. AP 4 may accept the update on the TWT parameter of the TWT schedule or the TWT agreement by sending a C-TWT parameter update response frame indicating the acceptance of the updates to AP 1.
Subsequently, AP 1 sends a second C-TWT parameter update notification frame to AP 3 and AP 4, indicating impending changes or updates to the TWT parameter of the TWT schedule or the TWT agreement. In response to the second C-TWT parameter update notification frame, AP 3 and AP 4 accepts the update by sending a C-TWT parameter update response frame to AP 1, indicating the acceptance of the updates on the TWT parameter of the TWT schedule or the TWT agreement.
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In some embodiments, a possible format of the C-TWT parameter update request frame is provided in the following Table 3.
Referring to Table 3, the C-TWT parameter update request frame includes a category field, an unprotected SIG action field, a dialog token field, and one or more TWT elements.
The category field may indicate a category to which the C-TWT parameter update response frame belongs. The unprotected SIG action field differentiates unprotected SIG action frame formats within predetermined unprotected S1G category. The dialog token field may be set to a nonzero value chosen by the AP sending the C-TWT parameter update response frame to identify the request/response transaction.
The TWT element in the C-TWT parameter update request frame may correspond to the TWT schedule or the TWT agreement for which parameters are pending changes or updates. For a broadcast TWT schedule, the Broadcast TWT ID of the updated TWT parameter set may be the same as the Broadcast TWT ID of the previous TWT parameter set which has been established between two or more APs. For an individual TWT agreement, the TWT Flow Identifier of the updated TWT parameter set may be the same as the TWT Flower Identifier of the previous TWT parameter set which has been established between two APs. Other TWT parameters in the TWT element may correspond to updated TWT parameters.
In some embodiments, a format of the C-TWT parameter update response frame in
In some embodiments, a first AP has successfully established TWT-based multi-AP coordination with a second AP in multi-AP coordination set for a TWT schedule or a TWT agreement identified by a first TWT parameter set. The first AP may be a TWT sharing AP and the second AP may be a TWT shard AP. In this scenario, the second AP may receive a C-TWT parameter update notification frame from the first AP notifying the second AP about the impending changes to the TWT parameters. If the second AP accepts the changes to the TWT parameters, the second AP starts advertising an updated TWT schedule with the updated TWT parameters. The updated TWT schedule and updated TWT parameters will take effect from the time indicated by the first AP. In some embodiments, the second AP advertises the updated TWT schedule in a frame carrying an TWT element including a second TWT parameter set in its BSS and the second TWT parameter set indicates the time when the updated TWT schedule and the updated TWT parameters takes effect. The following describes the process by which the second AP in its BSS advertises the updated TWT schedule.
The process 900 may begin in operation 901. In operation 901, a second AP establishes a TWT-based multi-AP coordination with a first AP in a multi-AP coordination set for a TWT schedule or a TWT agreement identified by a first TWT parameter set.
In operation 903, the second AP receives a C-TWT parameter update notification frame from the first AP indicating impending changes to TWT parameters and intending to replace the first TWT parameter set with a second TWT parameter set which can also be referred to as an updated TWT parameter set in this disclosure.
In operation 905, the second AP determines whether it accepts the changes to the TWT parameters of the first TWT parameter set. When the second AP accepts the changes, the process proceeds to operation 907. Otherwise, it proceeds to operation 911.
In operation 907, the second AP sends a C-TWT parameter update response frame to the first AP indicating the acceptance of the changes to the TWT parameter.
In operation 909, the second AP starts advertising the updated TWT schedule with the updated TWT parameters. The updated TWT schedule and the updated TWT parameter will take effect from the time indicated by the first AP. In some embodiments, the second AP advertises the updated TWT schedule in a frame carrying a TWT element with the second TWT parameter set in its BSS and the second TWT parameter set indicates the time indicated by the first AP in the C-TWT parameter update notification frame. The updated TWT schedule and the second TWT parameter set becomes effective from the indicated time.
In operation 911, the second AP does not advertise the updated TWT schedule corresponding to the second TWT parameter set. In some embodiments, the second AP stops advertising the existing TWT schedule corresponding to the first TWT parameter set, starting from the time indicated by the first AP in the C-TWT parameter update notification frame. As described, the updated TWT schedule and the second TWT parameter set take effect from the indicated time.
In some embodiments, a first AP has successfully established TWT-based multi-AP coordination with a second AP in multi-AP coordination set for a TWT schedule or a TWT agreement identified by a first TWT parameter set. The first AP may be a TWT sharing AP and the second AP may be a TWT shard AP. The second AP monitors and decodes a TWT element within a beacon frame or a probe response frame transmitted by the first AP. Consequently, the second AP can be aware of changes to the TWT parameter to the existing TWT schedule by the first AP. If the second AP observes any changes to the TWT parameters, the second AP advertises the updated TWT schedule with the updated TWT parameters starting the time indicated by the first AP. The updated TWT parameters becomes effective from the indicated time. In some embodiments, the start time may be indicated by the TWT persistence field in the TWT element. In these embodiments, no explicit negotiation between the two APs is needed to update any TWT parameter.
In
The Control field may include a null data PPDU (physical layer protocol data unit) (NDP) Paging Indicator subfield, a Responder power management (PM) Mode subfield, a Negotiation Type subfield, a TWT Information Frame Disabled subfield, a Wake Duration Unit subfield, a Link ID Bitmap Present subfield, and an OBSS R-TWT subfield. The NDP Paging Indicator subfield may indicate whether an NDP paging field is present or not in an Individual TWT Parameter Set field. The Responder PM Mode subfield may indicate the power management mode, such as active mode and power save (PS) mode. The negotiation Type subfield may indicate whether the information included in the TWT element is for the negotiation of parameters of broadcast or individual TWT or Wake TBTT (target beacon transmission time) interval. The MSB (most significant bit) of the Negotiation Type subfield is the Broadcast field which indicates if one or more Broadcast TWT Parameter Sets are contained in the TWT element. The TWT Information Frame Disabled subfield may indicate whether the reception of TWT information frame is disabled by the STA. The Wake Duration Unit subfield may indicate the unit of the Nominal Minimum TWT Wake Duration subfield in the Broadcast TWT Parameter Set field. The Link ID Bitmap Present subfield may indicate the presence of the Link ID Bitmap field in the Individual TWT Parameter Set field. The OBSS R-TWT subfield may indicate whether the R-TWT schedules corresponding to the Broadcast TWT Parameter Set fields in the TWT element are the R-TWT schedule of the neighboring BSS. When the OBSS R-TWT subfield is set to ‘1’, it may indicate that the R-TWT schedules in the TWT element are the R-TWT schedule of the neighboring BSS. Otherwise, it indicates that there is no neighboring BSS's R-TWT schedule in the TWT element.
The TWT Parameter information field includes an individual TWT parameter set field or one or more Broadcast TWT Parameter Set fields. For the convenience of description,
A reference to an element in the singular is not intended to mean one and only one unless specifically so stated, but rather one or more. For example, “a” module may refer to one or more modules. An element proceeded by “a,” “an,” “the,” or “said” does not, without further constraints, preclude the existence of additional same elements.
Headings and subheadings, if any, are used for convenience only and do not limit the invention. The word exemplary is used to mean serving as an example or illustration. To the extent that the term “include,” “have,” or the like is used, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. Relational terms such as first and second and the like may be used to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions.
Phrases such as an aspect, the aspect, another aspect, some aspects, one or more aspects, an implementation, the implementation, another implementation, some implementations, one or more implementations, an embodiment, the embodiment, another embodiment, some embodiments, one or more embodiments, a configuration, the configuration, another configuration, some configurations, one or more configurations, the subject technology, the disclosure, the present disclosure, other variations thereof and alike are for convenience and do not imply that a disclosure relating to such phrase(s) is essential to the subject technology or that such disclosure applies to all configurations of the subject technology. A disclosure relating to such phrase(s) may apply to all configurations, or one or more configurations. A disclosure relating to such phrase(s) may provide one or more examples. A phrase such as an aspect or some aspects may refer to one or more aspects and vice versa, and this applies similarly to other foregoing phrases.
A phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list. The phrase “at least one of” does not require selection of at least one item; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, each of the phrases “at least one of A, B, and C” or “at least one of A, B, or C” refers to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C.
It is understood that the specific order or hierarchy of steps, operations, or processes disclosed is an illustration of exemplary approaches. Unless explicitly stated otherwise, it is understood that the specific order or hierarchy of steps, operations, or processes may be performed in different order. Some of the steps, operations, or processes may be performed simultaneously or may be performed as a part of one or more other steps, operations, or processes. The accompanying method claims, if any, present elements of the various steps, operations or processes in a sample order, and are not meant to be limited to the specific order or hierarchy presented. These may be performed in serial, linearly, in parallel or in different order. It should be understood that the described instructions, operations, and systems can generally be integrated together in a single software/hardware product or packaged into multiple software/hardware products.
The disclosure is provided to enable any person skilled in the art to practice the various aspects described herein. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. The disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the principles described herein may be applied to other aspects.
All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using a phrase means for or, in the case of a method claim, the element is recited using the phrase step for.
The title, background, brief description of the drawings, abstract, and drawings are hereby incorporated into the disclosure and are provided as illustrative examples of the disclosure, not as restrictive descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, in the detailed description, it can be seen that the description provides illustrative examples and the various features are grouped together in various implementations for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separately claimed subject matter.
The claims are not intended to be limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims and to encompass all legal equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirements of the applicable patent law, nor should they be interpreted in such a way.
This application claims the benefit of priority from U.S. Provisional Application No. 63/464,415, entitled “PARAMETER UPDATE PROCEDURE FOR TWT-BASED MULTI-AP COORDINATION,” filed May 5, 2023, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63464415 | May 2023 | US |