Method and apparatus for calibrating and adjusting a clear media

Abstract

To provide a method and a device for ensuring that the spurious transmission due to STA calibration does not affect results of self-calibration of other STAs.SOLUTION: A method for calibrating a STA in a wireless communication network includes receiving a beacon frame containing a restricted access window (RAW) parameter set (RPS) information element (IE) and managing based on determining whether an association identity (AID) indicated in the RPS IE of the received beacon frame matches a calibration AID associated with the STA. The process further includes determining the RAW based on the RPS IE, and scheduling a RAW clear media calibration (RAW-cmc) event within the RAW based at least in part on a determination that the AID indicated in the RPS IE matches the calibration AID.SELECTED DRAWING: Figure 5D

Description

[Technical field]

[0001] [Related Applications] This application claims priority to Australian Provisional Patent Application No. 2023 / 900387, filed on February 16, 2023, entitled "Method and Apparatus for Clear Media Calibration Adjustment," the entirety of which is incorporated herein by reference for all purposes.

[0002] TECHNICAL FIELD The present disclosure relates generally to wireless communications. For example, aspects of the present disclosure relate to clear media calibration in wireless communications networks, such as wireless local area networks (WLANs). [Background technology]

[0003] An Access Point (AP) serves as a medium and manages one or more wireless devices, also known as stations (STAs), by creating a wireless communication network for communicating with each other through the AP. The AP allows the STAs to communicate bidirectionally with the AP and / or with other STAs connected to the AP. The AP may also allow all its associated STAs to connect to a wired or wireless communication network (e.g., the Internet, etc.). Before connecting to a particular wireless communication network, the STA sends an association request to the corresponding AP included in the particular wireless communication network. The association request sent by the STA and received by the AP may be used by the AP to check the validity of the STA, for example, by checking whether the STA has a matching service set identifier (SSID). The AP may then allow the association request (e.g., based on validation of the STA and / or the association request) or reject the association request (e.g., based on failure to validate the STA and / or the association request).

[0004] If the STA receives an association response from the AP indicating successful association, the STA is permitted to communicate or forward data frames to the AP, and the AP may forward the received data frames to one or more destination STAs. After successful association, the STA may require periodic self-calibration to align with the noise floor associated with communications with and / or from the STA (e.g., to maintain communication performance and / or for other operational reasons). The self-calibration process performed by the STA may require a quiet medium, such as a quiet wireless medium (WM) of the wireless communication network associated with the AP and the STA. Using a quiet medium during self-calibration can ensure that spurious transmissions do not affect the results of the STA's self-calibration.

[0005] In some examples, the time required for a quiet medium for an Institute of Electrical and Electronics Engineers (IEEE) 802.11ah HaLow-based STA can range up to 230 milliseconds (ms). A conventional HaLow-based STA may use a Clear To Send To Self (CTS-To-Self) mechanism to force a quiet medium during the STA's self-calibration. For example, a HaLow-based STA can be configured to transmit a CTS-To-Self frame indicating the time required for the STA to have exclusive access to the wireless medium. Other devices on the wireless network that receive and recognize this CTS-To-Self frame are configured to stay away from the wireless medium for a period of time.

[0006] The time to transmit a CTS-To-Self frame varies with the primary channel bandwidth and can be, for example, equal to the time to transmit a Null Data Packet (NDP) CTS plus the corresponding Short Interframe Space (SIFS). When transmitting on a 1 MHz channel in a Wi-Fi HaLow-based network, the time to transmit a CTS-To-Self frame is 720 microseconds (μs), while the time to transmit a CTS-To-Self frame on a 2 MHz channel is 400 μs. SIFS is the interval before the transmission of a CTS-To-Self frame and can indicate the time required for the air interface to process the received frame and respond with a response frame. For example, SIFS is equal to 160 μs. The time taken on the wireless medium for a single STA self-calibration event can be up to 230.88 ms (230 ms + 720 μs + 160 μs) in total. During this time, the wireless medium is not accessible for any kind of data transmission. Summary of the Invention [Problem to be solved by the invention]

[0007] The following provides a simplified summary of one or more aspects disclosed herein. As such, the following summary should not be considered as an extensive overview of all contemplated aspects, nor should it be intended to identify key or essential elements of all contemplated aspects or to delineate the scope associated with any particular aspect. As such, the following summary has the sole purpose of presenting certain concepts related to one or more aspects of the mechanisms disclosed herein in a simplified form prior to the detailed description presented below. [Means for solving the problem]

[0008] Systems, methods, apparatus, and computer-readable media for performing wireless communications over a wireless communication network, such as a wireless local area network (WLAN), are disclosed. According to at least one illustrative example, a method of wireless communication over a wireless communication network is provided, including a method for managing calibration of a station (STA). The method of managing calibration includes receiving a beacon frame including a Restricted Access Window (RAW) Parameter Set (RPS) Information Element (IE), determining whether an Association Identity (AID) indicated in an RPS IE of the received beacon frame matches a calibration AID associated with the STA, determining a RAW based on the RPS IE, scheduling a RAW clear media calibration (RAW-cmc) event in the RAW based at least in part on a determination that the AID indicated in the RPS IE matches the calibration AID, and performing a calibration of the STA as scheduled using the scheduled RAW-cmc event in the RAW.

[0009] In some aspects, the RPS IE indicates information corresponding to one or more of a start time associated with the RAW, a slot duration associated with the RAW, or a number of slots associated with the RAW.

[0010] In some aspects, to calibrate the STA on a schedule, the STA calibrates one or more physical (PHY) layer parameters in the RAW-cmc event during the RAW.

[0011] In some aspects, the RAW-cmc event is scheduled based on a further determination that the STA supports RAW-cmc, and the method further includes restricting any transmissions of the STA during the RAW based on a determination that the STA does not support RAW-cmc.

[0012] In some aspects, the method further includes, in response to determining that the AID indicated in the RPS IE matches the calibration AID, determining whether the STA requires calibration, scheduling the RAW-cmc event based on a determination that the STA requires calibration, and skipping scheduling of the RAW-cmc event based on a determination that the STA does not require calibration.

[0013] In some aspects, whether the STA requires calibration is determined based on the amount of time elapsed since the STA's last silent media calibration.

[0014] In some aspects, whether the STA requires calibration is determined based on one or more external events observed by the STA at a PHY layer associated with the STA.

[0015] In some aspects, the calibration AID is set by an access point (AP) associated with the STA, and the calibration AID comprises a static value set within a higher range of allowed AIDs.

[0016] In some aspects, the method further includes the steps of: sending, by the STA, an association request to associate with an AP in the wireless communication network; receiving from the AP an association response including the calibration AID and a RAW-cmc vendor IE indicating a calibration period for the RAW-cmc event; and storing, by the STA, the calibration AID and calibration period indicated in the RAW-cmc vendor IE.

[0017] In some aspects, the STA utilizes a silent medium for calibration, and the method further includes determining whether the STA supports RAW-cmc; determining whether the STA can defer performing calibration until a next RAW-cmc event based on a determination that the STA supports RAW-cmc; and in response to determining that the STA does not support RAW-cmc or that the STA cannot defer performing calibration until the next RAW-cmc event, transmitting a Clear To Send to Self (CTS-To-Self) frame by the STA to reserve a silent medium for calibration and perform calibration of the STA using the reserved silent medium corresponding to the CTS-To-Self frame.

[0018] In some aspects, the STA restricts any transmissions during the RAW based on a determination that the AID indicated in the RPS IE does not match a calibration AID stored by the STA and does not match an AID associated with the STA.

[0019] In some aspects, the technology described herein relates to a STA connected to a wireless communication network, the STA including a receiver and a transmitter, a processor communicatively coupled to the receiver and the transmitter, and one or more memory banks communicatively coupled to the processor and storing processor-readable code, which, when executed by the processor in cooperation with the receiver and the transmitter, causes the processor to receive a beacon frame including an RPS IE, determine whether an AID communicated in an RPS IE of the received beacon frame matches a calibration AID stored in the STA, determine a RAW according to the RPS IE, and if the AID communicated in the RPS IE matches the calibration AID, schedule a RAW-clear-media-calibration (RAW-cmc) event during the RAW, calibrate in the RAW-cmc event as scheduled, or limit any transmission during the RAW.

[0020] In some aspects, the techniques described herein relate to a method for managing calibration of a plurality of STAs in a wireless communication network, the method including: determining, by an AP associated with the plurality of STAs, an elapsed time since a last RAW-cmc event on a wireless medium; inserting an RPS IE including a RAW slot in a RAW associated with a calibration AID included in a beacon frame generated by the AP based on the elapsed time being greater than a predefined threshold time value; and transmitting the beacon frame from the AP over a wireless medium to one or more STAs in the wireless communication network, the wireless medium being reserved as a silent medium during the RAW slot in the RAW for the one or more STAs to perform calibration.

[0021] In some aspects, the method further includes receiving an association request from a STA in the wireless communication network, inserting a RAW-cmc vendor IE including the calibration AID and calibration period into an association response generated by the AP corresponding to the association request received from the STA, and transmitting the association response with the RAW-cmc vendor IE to the STA.

[0022] In some aspects, the RPS IE indicates information corresponding to one or more of a start time associated with a RAW, a slot duration associated with the RAW, or a number of slots associated with the RAW.

[0023] In some aspects, the method further includes receiving a CTS-To-Self frame from a STA indicating a request for calibration on a silent medium, and reserving a wireless medium by the STA to perform calibration in accordance with the CTS-To-Self frame, wherein the reserved wireless medium is not accessible for any data transfer during the reserved time.

[0024] In some aspects, the method further includes comparing the elapsed time since the last RAW-cmc event with a dynamic maintenance interval value obtained by the AP, and transmitting the beacon frame based on a determination that the elapsed time since the last RAW-cmc event is greater than the dynamic maintenance interval value.

[0025] According to some embodiments, the dynamic maintenance interval may be adaptively updated. In some aspects, adaptively updating the dynamic maintenance interval includes decreasing the dynamic maintenance interval in response to receiving an isolated CTS-To-Self frame by the AP, determining by the AP that a CTS-To-Self Partial AID matches a device in the wireless communication network, and determining by the AP that an average time between isolated CTS-To-Self frames is less than the dynamic maintenance interval and the dynamic maintenance interval is greater than a predetermined lower limit. The isolated CTS-To-Self frame may be defined as having a CTS time that is less than a valid frame time associated with the AP.

[0026] In some aspects, adaptively updating the dynamic maintenance interval further includes determining that an update timer associated with the AP has expired; determining, by the AP, whether the dynamic maintenance interval has decreased in any of the past 10 update intervals based on the expiration of the update timer; and extending the dynamic maintenance interval based on a determination that the dynamic maintenance interval has not decreased in any of the past 10 update intervals or using an unchanged dynamic maintenance interval value based on a determination that the dynamic maintenance interval has decreased in any of the past 10 update intervals.

[0027] In some aspects, the technology described herein relates to an AP connected to a wireless communication network, the AP including a receiver and a transmitter, a processor communicatively coupled to the receiver and the transmitter, and one or more memory banks communicatively coupled to the processor and storing processor-readable code that, when executed by the processor in cooperation with the receiver and the transmitter, is configured to: check whether a sufficient time has passed since a last RAW-cmc event, and if a sufficient time has passed since the last RAW-cmc event, insert an RPS IE including a RAW slot assigned to a calibration AID into a beacon frame, and transmit the beacon frame by the transmitter to one or more STAs in the wireless communication network, and schedule the current RAW-cmc event for device calibration.

[0028] In some aspects, the technology described herein relates to a wireless communication device, wherein the wireless communication device is an AP or a STA.

[0029] Other objects and advantages associated with the embodiments disclosed herein will become apparent to one of ordinary skill in the art upon review of the accompanying drawings and detailed description. [Brief description of the drawings]

[0030] Exemplary aspects of the present application will now be described in detail with reference to the following drawings.

[0031] [Figure 1A] 1 is a block diagram illustrating an example wireless communication network.

[0032] [Figure 1B] FIG. 2 illustrates an example of wireless medium reservation by multiple stations (STAs).

[0033] [Figure 2A]1 is a block diagram of a wireless communication device that can implement a station (STA) or an access point (AP) according to some embodiments.

[0034] [Figure 2B] 2B is a schematic block diagram of a receiver data flow architecture of the wireless communication device of FIG. 2A according to some embodiments.

[0035] [Figure 2C] 1 is a schematic block diagram of a transmitter data flow architecture that can be used to transmit radio frequency (RF) signals over a wireless medium according to some embodiments.

[0036] [Figure 3A] FIG. 1 illustrates an example of a Restricted Access Window (RAW) Parameter Set (RPS) Information Element (RPS IE) defined by the IEEE 802.11ah HaLow specification.

[0037] [Figure 3B] FIG. 3B illustrates an example of a RAW allocation subfield format associated with the RPS IE of FIG. 3A.

[0038] [Figure 3C] FIG. 3B illustrates an example of a RAW control subfield format associated with the RPS IE of FIG. 3A.

[0039] [Figure 3D] FIG. 3B illustrates an example of a RAW slot definition subfield format associated with the RPS IE of FIG. 3A.

[0040] [Figure 4] FIG. 2 illustrates an example of clear media calibration (CMC) that can be used to reserve the wireless medium for self-calibration using RAW functionality, according to some embodiments.

[0041] [Figure 5A] FIG. 1 is a flow diagram of an example wireless communication method implemented by an AP to perform RAW-based clear media calibration (RAW-cmc) by advertising support for RAW-cmc to a destination STA in an association response frame, according to some embodiments.

[0042] [Figure 5B] 1 is a flow diagram of an example method of RAW-cmc implemented by a STA based on receiving an association response from an AP indicating a RAW-cmc vendor IE, according to some embodiments.

[0043] [Figure 5C] FIG. 1 is a flow diagram of an example wireless communication method implemented by an AP to perform RAW-cmc in which the AP initiates an adjusted silent media calibration window based on an RPS IE that includes a preselected calibration association identifier (AID), according to some embodiments.

[0044] [Figure 5D] 1 is a flow diagram of an example method of RAW-cmc implemented by a STA based on receiving a beacon frame from an AP that includes an RPS IE indicating an AID, according to some embodiments.

[0045] [Figure 5E] 1 is a flow diagram of an example calibration method implemented by a STA capable of performing calibration using silent media external to RAW, according to some embodiments.

[0046] [Figure 5F] FIG. 13 is a wireless communication flow diagram for an AP to perform RAW-cmc using a dynamic interval update mode to respond to changing conditions that may require STAs to calibrate more frequently, according to some embodiments.

[0047] [Figure 5G] 1 is a flow diagram of an example wireless communication method implemented by an AP to perform RAW-cmc with gradually increasing dynamic maintenance intervals using a dynamic interval update mode, according to some embodiments.

[0048] [Figure 6] FIG. 13 illustrates a RAW-cmc calibration period graph illustrating dynamic RAW-cmc calibration period changes over time based on changing requirements of the network and / or STAs, according to one embodiment.

[0049] [Figure 7] 1 is a flow diagram of a wireless transmission method implemented in a STA according to some embodiments.

[0050] [Figure 8] FIG. 1 is a block diagram illustrating an example of a computing system for implementing certain aspects described herein, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Specific aspects of the present disclosure are described below. As will be apparent to one skilled in the art, some of these aspects can be applied independently and some of them can be applied in combination. In the following description, for the purpose of explanation, specific details are set forth in order to provide a thorough understanding of the aspects of the present application. However, it will be apparent that various aspects can be practiced without these specific details. The drawings and description are not intended to limit the present invention.

[0052] The following description provides exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the present disclosure. Rather, the following description of exemplary embodiments will provide those skilled in the art with an effective description for implementing the exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the spirit or scope of the invention as set forth in the appended claims.

[0053] As previously mentioned, in at least some examples, the duration of a self-calibration event by a Wi-Fi HaLow STA on the wireless medium can be up to 230.88 ms (consisting of a 230 ms silent medium period, 720 μs of CTS-To-Self frame transmission time on a 1 MHz channel, and 160 μs of SIFS). During this time, the wireless medium is inaccessible to any type of data transmission. As the use and deployment of Internet of Things (IOT) devices and Low Power Wide Area Network (LPWAN) devices increases, the number of STAs that may be present in a given area also increases. At this increasingly large deployment scale, the wireless medium can quickly become saturated or overwhelmed by multiple STAs each attempting to schedule a silent medium to perform self-calibration. For example, in the above example where self-calibration by a single STA on a Wi-Fi HaLow network takes 230.88 ms on the medium, fewer than five STAs can perform self-calibration per second, resulting in multiple STAs occupying the wireless medium for long periods of time with sequential self-calibration.

[0054] This principle is illustrated in the example of FIG. 1B. FIG. 1B illustrates an example of wireless medium reservation 150 by multiple stations (e.g., STA0, STA1, STA2, STA3). In the timeline of wireless medium reservation 150 illustrated in FIG. 1B, the four stations STA0-STA3 take turns reserving the wireless medium for self-calibration, resulting in long busy periods during which data transmission on the wireless medium is restricted. A Wi-Fi HaLow-based network can currently theoretically support up to 8,000 STAs simultaneously. Thus, the presence of a large number of STAs on a Wi-Fi HaLow network can result in significant performance degradation and network blocking, as each associated STA periodically reserves the wireless medium to perform self-calibration, resulting in the inability of any STA to communicate over the wireless medium for long periods of time.

[0055] There is a need for systems and techniques that can be used to provide network coordination among multiple STAs that periodically perform self-calibration in a wireless network, such as systems and techniques that can be used to provide support for self-calibration of a large number of STAs in a wireless communication network. Assuming a fully loaded Wi-Fi HaLow network of 8,000 stations, a total of 1,847 seconds of quiet time (230.88 ms*8,000) would be required for silent media calibration if a conventional CTS-To-Self mechanism is used. However, self-calibration is a periodic process and typically needs to be performed, for example, every 60 seconds to ensure that stations are properly synchronized with the AP. In particular, it is impractical to implement a CTS-To-Self mechanism for self-calibration in a wireless network with a large number of wireless devices, when the total silent media time required for self-calibration of all STAs far exceeds the period during which each STA performs self-calibration.

[0056] In particular, systems, methods, apparatus, and computer-readable media (collectively, "systems and techniques") are disclosed that provide novel and effective methods for performing clear media calibration for and / or within a wireless communication network supporting a large number of stations (STAs). An embodiment of a STA receives a beacon frame that includes and / or indicates a restricted access window (RAW) parameter set (RPS) information element (IE). Based on receiving the beacon frame including the RAW IE (e.g., received from an AP), the STA can determine whether an association identifier (AID) communicated in the RPS IE of the received beacon frame matches a calibration AID stored in the STA. The calibration AID can be configured or pre-configured in the memory of the STA, including at the time of manufacture or deployment of the STA and / or by the AP(s) associated with the STA. Based on the AID communicated in the RPS IE that matches a calibration AID associated with the STA, the STA can determine a RAW according to the RPS IE and schedule a RAW clear media calibration (RAW-cmc) event during the RAW. As a result, the STA will calibrate in the RAW-cmc event as scheduled. If the AID in the RPS IE does not match either the calibration AID or the STA's AID, the STA will leave the RAW and will not transmit or calibrate during the RAW.

[0057] In some embodiments, the systems and techniques described herein may use the RPS IE in the beacon frame to convey information corresponding to (e.g., indicative of) the start time of the RAW, the slot duration in the RAW, and / or the number of slots in the RAW. In some embodiments, the STA adjusts physical (PHY) layer related settings, parameters, and / or coefficients of the RAW-cmc event during the RAW. An embodiment of the STA may further determine whether the STA supports RAW-cmc and may restrict any transmission during the RAW if the STA does not support RAW-cmc. If the AID communicated in the RPS IE matches a calibration AID, the STA may adaptively determine whether calibration is required and schedule a RAW-cmc event only if calibration is required. For example, the STA determines whether calibration is required based on the duration since the last silent media calibration. In another example, the STA determines whether calibration is required based on one or more external events observed at the PHY layer.

[0058] During association, the STA transmits an association request to an access point (AP) in the wireless communication network and receives an association response from the AP. In some embodiments, the AP inserts a RAW-cmc vendor IE including a calibration AID and a calibration period into the association response. The STA extracts and stores the calibration AID and calibration period communicated in the RAW-cmc vendor IE to determine whether the STA can perform self-calibration in a subsequent RAW. In some embodiments, if the STA determines that it requires a quiet medium for calibration outside of a RAW and that the STA supports RAW-cmc, the STA may then determine whether the STA can wait until the next RAW-cmc event to perform the calibration. In some embodiments, if the STA does not support RAW-cmc or if the STA cannot wait until the next RAW-cmc event, the STA may be configured to transmit a CTS-To-Self frame to reserve a quiet medium for calibration and then perform the calibration in the quiet medium reserved by the CTS-To-Self frame.

[0059] In one illustrative example, systems and techniques are provided for a STA to connect to a wireless communication network. The STA includes a receiver, a transmitter, a processor communicatively coupled to the receiver and the transmitter, and one or more memory banks. The memory bank communicatively coupled to the processor stores processor-readable code. The processor-readable code, when executed by the processor in cooperation with the receiver and the transmitter, is configured to: receive a beacon frame including an RPS IE by the receiver; determine whether an AID communicated in the RPS IE of the received beacon frame matches a calibration AID stored in the STA; determine a RAW according to the RPS IE; and if the AID communicated in the RPS IE matches the calibration AID, schedule a RAW-cmc event during the RAW, calibrate in the RAW-cmc event as scheduled, or limit any transmission during the RAW.

[0060] An embodiment of a method for clear media calibration of an AP in a wireless communication network includes checking whether a sufficient time has passed since a last RAW-cmc event on a wireless medium, and if a sufficient time has passed since the last RAW-cmc event, inserting an RPS IE into a beacon frame including a RAW slot assigned to a calibration AID, and transmitting the beacon frame on the wireless medium to one or more STAs in the wireless communication network. The wireless medium is reserved as a silent medium during the RAW slots of the RAW so that one or more STAs can calibrate simultaneously. In some embodiments, the AP receives an association request from a STA that wishes to join the wireless communication network, inserts a RAW-cmc vendor IE including a calibration AID and a calibration periodicity into an association response, and transmits the association response to the STA. An embodiment of the RPS IE carries information corresponding to a start time of the RAW, a slot duration in the RAW, and a number of slots in the RAW.

[0061] In one embodiment, when the AP receives a CTS-To-Self frame from a STA requesting calibration on a quiet medium, the AP schedules a self-calibration event for the STA to calibrate, and the medium is not accessible to any data transfer. In some embodiments, the AP checks whether the time since the last RAW-cmc event is sufficient according to the dynamic maintenance interval, and schedules the current RAW-cmc event for device calibration if the time since the last RAW-cmc event exceeds the dynamic maintenance interval. The AP can adaptively update the dynamic maintenance interval. In one embodiment of adaptively updating the dynamic maintenance interval, if an isolated CTS-To-Self frame is received, the CTS-To-Self part AID matches a device in the wireless communication network, the average time between isolated CTS-To-Self frames is less than the dynamic maintenance interval, and the dynamic maintenance interval is greater than a lower limit, the AP decreases the dynamic maintenance interval. Otherwise, the dynamic maintenance interval remains unchanged. An isolated CTS-To-Self frame is defined as one that has a CTS time less than a valid frame time. In another embodiment for adaptively updating the dynamic maintenance interval, if the dynamic maintenance interval has not decreased in any of the past 10 update intervals, the dynamic maintenance interval is increased, otherwise the dynamic maintenance interval remains unchanged.

[0062] One embodiment of the present invention provides an AP connected to a wireless communication network, the AP including a receiver and a transmitter, a processor, and one or more memory banks communicatively coupled to the processor and storing processor-readable code, the AP executes the processor-readable code by the processor in cooperation with the receiver and the transmitter to check whether a sufficient time has passed since the last RAW-cmc event, and if a sufficient time has passed since the last RAW-cmc event, inserts an RPS IE including a RAW slot assigned to the calibration AID into a beacon frame, and transmits the beacon frame by the transmitter to one or more STAs in the wireless communication network to schedule the current RAW-cmc event for device calibration.

[0063] FIG. 1A is a block diagram illustrating an exemplary wireless communication network 100. In some aspects, the wireless communication network 100 may be an example of a wireless local area network (WLAN). As used herein, a WLAN may be a Wi-Fi network. In some examples, the WLAN 100 may be a network that implements at least one of the IEEE 802.11 family of wireless communication protocol standards (e.g., such as, but not limited to, those defined by the IEEE 802.11-2020 specification or amendments thereto, including 802.11ah, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be). The WLAN 100 may include at least one AP 102 and a plurality of associated STAs 104. For example, the STAs 104 may include a first STA 104a, a second STA 104b, a third STA 104c, a fourth STA 104d, and the like. Although only one AP 102 is shown, the WLAN network 100 may include multiple APs 102 .

[0064] Each of the STAs 104a-104d may also be referred to as a mobile station (MS), a mobile device, a mobile handset, a wireless handset, an access terminal (AT), a user equipment (UE), a subscriber station (SS), and / or a subscriber unit. The STAs 104 may represent a variety of devices, such as a mobile phone, a handheld device, a netbook, a computer, a tablet computer, a laptop, a display device (e.g., a TV, a computer monitor, a navigation system, etc.), a music or other audio device or stereo device, a remote control device ("remote control"), a printer, a kitchen or other home appliance, a key fob (e.g., a passive keyless entry and start (PKES) system), etc.

[0065] A single AP 102 and the set of associated STAs 104a-104d may be referred to as a Basic Service Set (BSS) managed by each AP 102. Figure 1A further illustrates an example of a coverage area 106 of an AP 102, which may represent a Basic Service Area (BSA) of the WLAN 100. A BSS may be identified to users by a Service Set Identifier (SSID) and to other devices by a Basic Service Set Identifier (BSSID), which may be the Media Access Control (MAC) address of the AP 102.

[0066] The AP 102 periodically broadcasts a beacon frame ("beacon") including the BSSID to allow any STAs (e.g., one or more, or all of the STAs 104a-104d) within radio range of the AP 102 to associate (or reassociate) with the AP 102 and establish a corresponding communication link 108a-108d (e.g., also referred to below as a "Wi-Fi link"). For example, the first STA 104a can establish a corresponding communication link 108a with the AP 102, the second STA 104b can establish a corresponding communication link 108b with the AP 102, the third STA 104c can establish a corresponding communication link 108c with the AP 102, and the fourth STA 104d can establish a corresponding communication link 108d with the AP 102. The STAs 104a-104d can further use the beacon frames broadcast by the AP 102 to maintain the corresponding communication links 108a-108d with the AP 102. For example, a beacon may include an identification of a primary channel used by a corresponding AP 102, as well as a timing synchronization function for establishing or maintaining timing synchronization with the AP 102. An AP 102 may provide various STAs within a WLAN with access to external networks via a corresponding communication link 108.

[0067] To establish a communication link 108a-108d with the AP 102, each corresponding STA 104a-104d may perform passive or active scanning operations ("scans") on frequency channels in one or more frequency bands. For example, to perform a passive scan, each of the STAs 104a-104d listens for beacons transmitted by the AP 102 at periodic time intervals called target beacon transmit times (TBTTs). The TBTTs may be measured in time units (TUs). In some examples, one TU may equal 1024 microseconds (μs). In some examples, the TBTTs may have a default value of 102.4 milliseconds (ms). To perform an active scan, each of the STAs 104a-104d may generate and transmit a probe request sequentially on each channel to be scanned and listen for a probe response from the AP 102. Each of the STAs 104a-104d may be configured to identify or select an AP 102 to associate with (e.g., based on scanning information obtained via passive or active scanning) and perform authentication and association operations to establish a corresponding communication link 108a-108d with the selected AP 102. The AP 102 assigns an association identifier (AID) to each of the STAs 104a-104d at the end of the association operation, which the AP 102 uses to track the STAs 104a-104d.

[0068] In some cases, one or more of the STAs 104a-104d may have the opportunity to select one of many BSSs within range of the STA, or to select from multiple APs 102 that form an extended service set (ESS) that includes multiple connected BSSs. The extended network stations associated with the WLAN 100 may be connected to a wired or wireless distribution system that allows multiple APs 102 to be connected within the ESS. In some examples, one or more of the STAs 104a-104d may be covered by multiple APs 102 and may associate with different APs 102 at different times for transmission. After association with an AP 102, one or more of the STAs 104a-104d may be configured to periodically scan the surroundings to find a more suitable AP with which to associate. For example, a given one of the STAs 104a-104d that is moving away from its associated AP 102 may perform a "roaming" scan to find another AP with more desirable network characteristics (e.g., a greater received signal strength indicator (RSSI), reduced traffic load, etc.).

[0069] In some cases, the STAs 104a-104d may form a network without any other equipment other than the AP 102 or the STAs 104a-104d themselves. One example of such a network is an ad-hoc network. Examples of ad-hoc networks include mesh networks and peer-to-peer (P2P) networks. In some cases, the ad-hoc network may be implemented within a larger wireless network. In such an implementation, the STAs 104a-104d may communicate with each other via the AP 102 using corresponding communication links 108a-108d, but the STAs 104a-104d may also communicate with each other directly using a direct wireless link 110. In some examples, two STAs may communicate via the direct communication link 110 regardless of whether both STAs 104 are associated with and served by the same AP 102. In such an ad-hoc system, one or more of the STAs 104a-104d may assume the role filled by the AP 102 in the BSS. Such a STA may be referred to as a Group Owner (GO) and may coordinate transmissions within the ad-hoc network. Examples of direct wireless links 110 include one or more of a Wi-Fi Direct connection, a connection established by using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, other P2P group connections, and the like.

[0070] The AP 102 and the STAs 104a-104d can function and communicate using their respective communication links 108a-108d in accordance with at least one of the IEEE 802.11 wireless communication protocol standards. These standards define WLAN radio and baseband protocols at the physical layer (PHY) and media access control (MAC) layers. For example, the AP 102 and the STAs 104a-104d transmit and receive wireless communications with each other in the form of PHY Protocol Data Units (PPDUs) or Physical Layer Convergence Protocol (PLCP) PDUs. The AP 102 and the STAs 104a-104d in the WLAN 100 can transmit PPDUs over licensed or unlicensed spectrum, which may be a portion of the spectrum including frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5 GHz band, the 60 GHz band, the 3.6 GHz band, and the sub-1 GHz band. Some implementations of the AP 102 and STAs 104a-104d described herein may also communicate over other frequency bands, such as the 6 GHz band, which may support both licensed and unlicensed communications. The AP 102 and STAs 104a-104d may also be configured to communicate over other frequency bands, such as shared licensed frequency bands, in which multiple operators may have licenses to operate within the same or overlapping frequency bands.

[0071] Each frequency band may include multiple sub-bands or frequency channels. For example, a PPDU conforming to the IEEE 802.11 standard and specification may be transmitted over a frequency band divided into multiple 20 MHz channels. In such an example, the PPDU is transmitted over a physical channel with a minimum bandwidth of 20 MHz, although other channel bandwidths are possible. In some cases, a larger bandwidth channel may be formed using channel bonding to combine multiple channels of the minimum bandwidth.

[0072] Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PHY service data unit (PSDU). Information provided in the preamble may be used by a receiving device to decode subsequent data in the PSDU. If the PPDU is transmitted on a bonded channel, the preamble field may be replicated and transmitted on each of the multiple component channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble may be used for packet detection, automatic gain control, channel estimation, etc. The legacy preamble may be used to maintain compatibility with typically legacy devices. The format, coding, and information provided in the non-legacy portion of the preamble are based on the particular IEEE 802.11 protocol used to transmit the payload.

[0073] 2A is a high-level block diagram of an exemplary wireless communication device 200 that may be used to implement a STA or an AP in some examples. The wireless communication device 200 may include a MAC layer and a PHY layer in accordance with one or more of the IEEE 802.11 standards.

[0074] The wireless communication device 200 includes a radio frequency (RF) transmitter module 202, an RF receiver module 204, an antenna unit 206, one or more memory banks 208, an input / output interface 210, and a system bus 212. The RF transmitter module 202 and the RF receiver module 204 include a modem (modulator-demodulator) that transmits data by modulating one or more carrier signals to encode digital information and receives data by demodulating the signals to recover the original digital information. As shown, the wireless communication device 200 further includes a MAC processor 214, a PHY processor 216, and a HOST processor 218. These processors can be any type of integrated circuit (IC), including a general-purpose processing unit, an application specific integrated circuit (ASIC), or a reduced instruction set computer 5 (RISC-V) based IC, etc.

[0075] The memory 208 can be used to store software and / or computer readable instructions, including software or instructions that can be used to implement at least some functionality of the MAC layer. For example, each processor included in the wireless communication device 200 (e.g., the MAC processor 214, the PHY processor 216, the HOST processor 218, etc.) executes respective software to implement respective communication / application layer functionality.

[0076] The PHY processor 216 includes a transmit signal processing unit and a receive signal processing unit (not shown) and can be used to manage the interface with the wireless medium (WM). The PHY processor 216 operates on the PPDU by exchanging digital samples with a radio module that includes the RF transmitter 202, the RF receiver 204, an analog-to-digital converter, and a digital filter.

[0077] The MAC processor 214 executes MAC level instructions and manages the interface between the application software and the WM via the PHY processor 216. The MAC processor 214 is responsible for coordinating access to the WM so that within range access points (APs) and STAs can communicate effectively. The MAC processor 214 adds header and tail bytes to units of data provided by higher levels and sends them to the PHY layer for transmission. The reverse occurs when receiving data from the PHY layer. If a frame is received in error, the MAC processor 214 manages the retransmission of the frame.

[0078] The HOST processor 218 is responsible for interfacing with the MAC layer and performing the higher level functions of the wireless communication device.

[0079] The PHY processor 216, the MAC processor 214, the HOST processor 218, the peripheral bus 220, the memory 208, and the input / output interface 210 communicate with each other via a system bus 212. The peripheral bus 220 connects to multiple peripherals that support the core functions of the wireless communication device 200, including timers, interrupts, radio / filter / system registers, counters, UARTs, GPIO interfaces, and the like. The memory 208 can further store an operating system and applications. In some examples, the memory stores record information about captured frames and packets. The input / output interface unit 210 enables information exchange with a user of the wireless communication device. The antenna unit 206 can include a single antenna and / or multiple antennas. For example, multiple antennas can be used to implement multiple-input multiple-output (MIMO) technology, among others.

[0080] FIG. 2B shows a schematic block diagram of a receiver data flow architecture 250 that can be used to receive Wi-Fi packets over a network. In one illustrated example, the receiver data flow architecture 250 shown in FIG. 2B can correspond to or relate to the wireless communication device 200 shown in FIG. 2A. A wireless signal is received via the WM and converted to an electrical signal via a receive antenna 252 (e.g., which may be the same as or similar to the antenna 206). The received signal is conditioned using a series of analog filters 254 (e.g., shown as analog RF receive (Rx) filters) before being converted to an equivalent digital signal using an analog-to-digital converter (ADC) 256. The sampled signal output of the ADC 256 is again conditioned using a filter bank 258, which may include one or more digital RF filters and / or farrows, before the samples are collected in an asynchronous receive first-in-first-out (FIFO) data structure 260.

[0081] The samples in the FIFO structure 260 are accessible by multiple modules. For example, the samples may be accessed by a packet detection module and a sub-band module, both of which may be included in the lower level PHY section 262 shown in Figure 2B. In some embodiments, the lower level PHY section 262 is itself included in the PHY processor 216 shown in Figure 2A.

[0082] The packet detection module included in the lower level PHY section 262 may include hardware and / or implemented algorithms that may be used to analyze an initial section of a PPDU in the time domain. Based on the analysis, the packet detection module may be used to recognize a received frame and synchronize the frequency and timing of the wireless communication device with the packet being received. The sub-band module included in the lower level PHY section 262 may include hardware and / or implemented algorithms that may be used to detect which sub-channel within an assigned frequency band is being used for a packet being received.

[0083] Once a packet is detected and the associated sub-channel is established, the samples can be forwarded to an upper level PHY unit 264. The upper level PHY unit 264 can be included in the PHY processor 216 shown in FIG. 2A. In some aspects, the upper level PHY unit 264 can be used to process and decode the Orthogonal Division Multiplexing (OFDM) symbols (e.g., with the support of a co-processor module) to reconstruct the complete PPDU. The reconstructed PPDU is output by the upper level PHY unit 264 and then processed by the MAC layer processor 266. The MAC layer processor 266 can be used to extract the data payload from the PPDU and provide the relevant information to the HOST layer 268 for consumption.

[0084] In some examples, the MAC layer processor 266 shown in Figure 2B may be the same as or similar to the MAC processor 214 shown in Figure 2A. In some cases, the HOST layer 268 shown in Figure 2B may include or be the same as or similar to the HOST processor 218 shown in Figure 2A.

[0085] FIG. 2C is a schematic block diagram of a transmitter data flow architecture 280 that can be used to transmit RF signals over a wireless medium, according to some embodiments. More specifically, FIG. 2C illustrates a simplified schematic block diagram of a transmitter data flow architecture 280 used to transmit wireless signals over a WM. Data may be generated from a HOST or APP module 282 and packaged into a MAC-level protocol data unit (MPDU) and routed over a wireless network by a MAC management module 284. A PHY module 286 interfaces with the WM and compiles a PPDU by adding a PHY preamble and tail to the MPDU. Typically, a modulation coding scheme (MCS) for transmitting packets over the medium is established using a rate control algorithm by the MAC module 284 or the PHY module 286. The selected modulation scheme can define the modulation technique and coding rate used to transmit data over the WM. Based on the selected modulation scheme, e.g., quadrature amplitude modulation (QAM) 64, the PPDU is modulated to be transmitted over the WM. The encoder module 288 generates a signal corresponding to a point of a QAM constellation symbol (a group of bits of a PPDU) that can be encoded using polar coordinates (r-θ) or Cartesian coordinates (QI). The modulation is performed by linking the encoder module 288 to a digital phase-locked loop (DPLL) 290. The modulated signal can be filtered by an analog filter 292 and transmitted using a transmit antenna 294.

[0086] The embodiments of the present disclosure utilize a new MAC layer feature introduced in IEEE 802.11ah HaLow, known as the Restricted Access Window (RAW), for tuning the silent media self-calibration. As used herein, the technique of tuning the silent media for self-calibration via the RAW feature may be referred to as "RAW clear media calibration" and / or "RAW-cmc". The RAW feature is designed for applications where the network supports a large number of synchronous streams, such as multiple video cameras associated with one AP. A RAW is an interval where uplink channel access is permitted or enabled for only a subset of STAs in an assigned RAW group. STAs that do not belong to the subset corresponding to the assigned RAW group are prohibited from transmitting in a RAW scheduled for the assigned RAW group. To further reduce simultaneous contention, channel access attempts may be distributed across multiple slots within the entire RAW period. An assigned STA or a subset of STAs may access the wireless medium in a slot using Enhanced Distributed Channel Access (EDCA). In an assigned slot within a RAW, a STA may limit transmissions within the slot period or cross a slot boundary to continue transmission if permitted. Slot allocation among assigned STAs in a RAW is based on a Traffic Indication Map (TIM) element in a beacon frame transmitted from the AP to the STAs. The AP may also assign specific slots to individual STAs and / or various subsets of STAs for uplink and / or downlink traffic by indicating the slot allocation in a resource allocation frame transmitted at the start of the RAW.

[0087] A beacon frame is a type of management frame that contains information about the network. Beacon frames are sent periodically to announce the presence of the network, synchronize members of a service set, and inform members of a service set of the presence of buffered data traffic. The RAW Parameter Set (RPS) information element (IE) can be sent in a beacon frame to advertise the presence of a RAW to all clients. A client cannot transmit during a RAW unless it is part of this particular RAW group, as indicated by the RPS IE.

[0088] The RPS IE may further provide information indicating which clients in a particular RAW group are allowed to transmit in the RAW. For example, each client in a particular RAW group may be aware of the availability of slots in which it can transmit based on the Timer Synchronization Function (TSF) settings. The RPS IE format defined by the HaLow specification is shown in Figure 3A, described below.

[0089] 3A is a diagram illustrating an example of the format of an RPS IE 300 defined by the IEEE 802.11ah HaLow specification, according to some embodiments. As shown, the RPS IE 300 includes an Element ID field 302 (in some embodiments, one octet in length), a Length 304 field (in some embodiments, one octet in length), and a RAW Allocation 306 field (in some embodiments, variable length).

[0090] Each RPS IE 300 may have multiple RAW allocation fields 306 to describe the configuration of multiple RAWs between two beacon frames. The RAW allocation subfield format 306 shown in FIG. 3B may be the same as or similar to the RAW allocation field 306 of FIG. 3A. In particular, FIG. 3B illustrates an example of a RAW allocation subfield format 306 that may be associated with the RPS IE format 300 of FIG. 3A, according to some embodiments. The RAW allocation field 306 may always include at least a RAW control 322 and a RAW slot definition 324 subfield. The RAW allocation field 306 may optionally include one or more of a RAW start time 326, a RAW group 327, a channel indication 328, and / or a periodic operation parameters 329 subfield.

[0091] Figure 3C further illustrates the RAW control subfield 322 of Figure 3B. In particular, Figure 3C illustrates an example of a RAW control subfield 322 that may be the same as or similar to the RAW control subfield 322 of Figure 3B, according to some embodiments. In some aspects, the RAW control subfield 322 of Figure 3B / RAW control subfield 322 of Figure 3C conveys information such as RAW type 342, RAW type options 343, start time indication 344, RAW group indication 345, channel indication presence information 346, and / or periodic RAW indication information 347.

[0092] FIG 3D illustrates a RAW slot definition subfield format (e.g., RAW slot definition 324 of FIG 3B) that, in some embodiments, may be the same as or similar to RAW slot definition subfield 324 of FIG 3B. As shown, RAW slot definition subfield 324 of FIG 3B / RAW slot definition subfield 324 of FIG 3D may carry (e.g., indicate) information such as a slot definition format indication 352, a cross slot boundary 354, a slot duration count 356, and / or a number of slots 358.

[0093] In some embodiments of RAW-clear media calibration (RAW-cmc), the AP specifies a RAW calibration service period in the RPS IE of the beacon frame by setting a preselected calibration association ID (AID) range for self-calibration. The AP ensures that the preselected calibration AID indicating the RAW calibration service period is not assigned to any STA in the basic service set (BSS). The AP assigns a unique AID to a STA that successfully associates with the AP. In some embodiments, the preselected calibration AID can be set to a static value in the higher range of the allowed AIDs. When the AP receives an association request from the STA, the AP inserts the preselected calibration AID for self-calibration and information about the calibration period in the association response and sends the association response to the STA.

[0094] The AP then uses the beacon frame to advertise the RAW for device calibration. For example, the AP can utilize an RPS IE that includes a single RAW slot assigned to a preselected calibration AID in the beacon frame. STAs in the BSS associated with the AP receive the beacon frame that includes the RAW information. These STAs can schedule their silent media self-calibration according to the RAW start time without reserving the wireless medium. STAs that do not support this RAW calibration function are excluded from the service period due to the RAW characteristics and the requirement to comply with the RAW function.

[0095] In some embodiments, the silent self-calibration can include PHY calibration. In one illustrative example, the silent self-calibration / PHY calibration can include either or a combination of direct current (DC) calibration and in-phase quadrature (IQ) calibration. In some aspects, the DC calibration can be performed based on measuring IQ samples in a wireless signal received by the STA, calculating an average or median value of the IQ samples, and adjusting amplifier settings to reduce the portion of the DC component in the wireless signal. In some examples, the IQ calibration can be performed based on transmitting a tone via a transmitter (Tx) of the STA, detecting the difference between the I and Q components by an envelope detector of the STA, and adjusting a phase or amplitude coefficient to reduce the difference between the I and Q components. The DC calibration can be performed to find optimal values ​​of settings, parameters, and / or coefficients to minimize the DC component entering the system. Similarly, the IQ calibration can be performed to find optimal values ​​of settings, parameters, and / or coefficients to minimize the IQ difference.

[0096] The present disclosure will be described with reference to Figure 4. Figure 4 illustrates an example of a clear media calibration (CMC) 400 that can be used to reserve a wireless medium for self-calibration using RAW functionality, according to some embodiments. For example, Figure 4 illustrates one embodiment of a RAW-cmc technique that reserves a wireless medium for self-calibration using RAW. The horizontal axis of the graph 400 in Figure 4 represents time, shown here in units of microseconds (μs). The vertical axis of the graph 400 in Figure 4 represents the power of a signal transmitted on the wireless medium.

[0097] In this embodiment, the AP transmits beacon frames via AP transmissions 402-1 and 402-2. A first STA transmits data via STA(1) transmissions 410-1, 410-2, 410-3, and 410-4, a second STA transmits data via STA(2) transmissions 414-1 and 414-2, and a third STA transmits data via STA(3) transmissions 418-1 and 418-2.

[0098] In one illustrative example, an AP may be configured to transmit a beacon frame 405 including an RPS IE indicating information corresponding to a RAW scheduled for self-calibration. For example, a first AP transmission 402-1 includes a beacon frame 405. In some embodiments, both the start AID and the end AID of the RAW are set (e.g., configured to and / or indicated to each STA associated with the AP) to be equal to a pre-selected calibration AID for self-calibration.

[0099] In this example, the RAW start time is set to x microseconds (μs), the RAW slot duration is set to y μs, and the RAW slot count is set to 1. In the clear media calibration example shown in graph 400 of FIG. 4, a first device STA(1) has two transmissions before the RAW start time at x μs (e.g., first STA(1) transmission 410-1 and second STA(1) transmission 410-2).

[0100] Following the RAW start time at x μs, the wireless medium is reserved as a quiet medium for self-calibration during RAW, thereby allowing STAs associated with the AP to simultaneously perform self-calibration. RAW 430 shown in FIG. 4 corresponds to a quiet medium reservation time during which the wireless medium is reserved for device calibration. After a RAW 430 end time (e.g., equal to the RAW start time at x μs+RAW slot number*RAW slot duration), devices associated with the AP, such as STA(1), STA(2), STA(3), etc., can again transmit on the wireless medium, e.g., as shown as the sequence of transmissions 410-3, 414-1, 418-1, 402-2, 410-4, 414-2, 418-2, ..., etc., shown in FIG. 4.

[0101] 5A-5G show flow diagrams illustrating respective embodiments of the presently disclosed systems and techniques for RAW clear media calibration and adjustment. In some aspects, process 500a of FIG. 5A, process 500c of FIG. 5C, process 500f of FIG. 5F, and / or process 500g of FIG. 5G may be implemented by an AP. In some aspects, process 500b of FIG. 5B, process 500d of FIG. 5D, and process 500e of FIG. 5E may be implemented by one or more STAs associated with the AP.

[0102] FIG. 5A is a flow diagram of a wireless communication process 500a implemented by an AP to perform RAW-based clear media calibration (RAW-cmc), in which the AP is configured to advertise support for RAW-cmc in an association response frame sent to a destination STA, in accordance with some embodiments.

[0103] In one illustrative example, AP support for the RAW-cmc method may be communicated or signaled to STAs associated with the AP using one or more vendor IEs having a predefined structure recognized by supporting devices (e.g., STAs), where the vendor IE indicates that the AP is enabled to support the RAW-cmc method for self-calibration by the STAs. For example, the vendor IE used to indicate RAW-cmc support by the AP may be provided as a RAW-cmc vendor IE.

[0104] In process 500a of FIG. 5A, the AP may receive an association request from a STA and prepare to send an association response to the STA (also referred to as the destination STA) at block 510.

[0105] At block 512, it is determined whether AP support for RAW-cmc is enabled. An AP may or may not support the RAW-cmc method. In some embodiments, an AP that supports the RAW-cmc method can adaptively enable or disable the RAW-cmc feature.

[0106] If the RAW-cmc method is supported and enabled by the AP (e.g., the "Y" or "yes" branch from decision block 512), the AP inserts a RAW-cmc Vendor IE into the association response to the association request from the destination STA, indicating a preselected calibration AID and a calibration period based on a Time Synchronization Function (TSF). The RAW-cmc Vendor IE may be a vendor IE recognized by and configured for STAs supporting the RAW-cmc method, as described above. The calibration period indicates how often the AP schedules quiet time for device calibration.

[0107] In some embodiments, a STA may be configured to signal to the AP upon association (e.g., in the association request sent to the AP at block 510 or in response to receiving an association response from the AP at block 516) one or more clear media calibration requirements or parameters corresponding to that particular STA. For example, upon association with the AP, the STA may signal clear media calibration requirements, such as periodicity or typical calibration period required or implemented by the STA.

[0108] In some embodiments, the STA-specific clear media calibration requirements can be signaled to the AP at association time using a vendor IE sent from the STA to the AP. Upon receiving and signaling a clear media calibration requirement from the STA at association time, including a vendor IE for the STA indicating the STA-specific clear media calibration requirements, the AP can be configured to store the information locally.

[0109] The AP may then be configured to determine one or more aggregate values ​​and / or aggregate information from the multiple vendor IEs sent from the STAs to the AP at each point of association. For example, the AP may aggregate STA-specific clear media calibration requirements and / or vendor IEs received by the AP from the AP and some or all of the multiple STAs associated with the same BSS.

[0110] In one illustrative example, the AP may analyze the aggregate information determined from the STA-specific clear media calibration requirements or parameters to determine, select, or set an optimal periodicity and / or duration of the RAW-cmc Vendor IE that the AP inserts into the association response at block 514 (e.g., the AP determines an optimal periodicity and / or duration of the RAW-cmc Vendor IE to be inserted into the association response at block 514 and then sent to the STA at block 516). In some embodiments, the AP may statically determine the optimal periodicity and / or duration of the RAW-cmc Vendor IE to be inserted into the association response based on the aggregated STA-specific CMC requirements and / or the AP may dynamically determine the optimal periodicity and / or duration of the RAW-cmc Vendor IE to be inserted into the association response based on the aggregated STA-specific CMC requirements. For example, the AP may dynamically change one or more of the periodicity and duration of the RAW-cmc vendor IE inserted into the association response in block 514 based on different STA-specific requirements of the STAs that may associate with the AP.

[0111] At block 516, the AP sends an association response to the destination STA, which is the STA from which the AP received the initial association request, as described above, at block 510. If RAW-cmc is not supported or enabled by the AP, process 500a may proceed from block 512 to block 516 without performing block 514 to insert a RAW-cmc vendor IE into the association response (e.g., the "N" or "No" branch from decision block 512).

[0112] FIG. 5B is a flow diagram of a process 500b of RAW-cmc implemented by a STA based on receiving an association response from an AP indicating a RAW-cmc vendor IE, according to some embodiments.

[0113] At block 520, the STA receives an association response from the AP that received the previous association request sent by the STA. According to one embodiment, the association response received by the STA at block 520 may include and / or indicate a RAW-cmc vendor IE.

[0114] At block 522, it is determined whether the STA supports RAW-cmc and / or whether RAW-cmc is enabled for the STA. If it is determined that the STA supports RAW-cmc and the RAW-cmc capability is enabled, process 500b proceeds to block 524. At block 524, the STA may obtain and store the preselected calibration AID and calibration period indicated / included in the RAW-cmc Vendor IE of the association response received by the STA from the AP at block 520. If the STA does not support RAW-cmc or if the RAW-cmc capability is disabled, process 500b ends.

[0115] 5C is a flow diagram of a process 500c of wireless communication implemented by an AP to perform RAW-cmc, in which the AP initiates an adjusted silent media calibration window based on an RPS IE that includes a preselected calibration association identifier (AID), according to some embodiments. For example, the RPS IE of process 500c can be an RPS IE defined by IEEE 802.11ah HaLow, and may be the same as or similar to the RPS IE format 300 of FIG. 3A.

[0116] 5C illustrates an example of an AP initiating a coordinated quiet media calibration window by transmitting a beacon frame including an RPS IE indicating a preselected calibration AID, according to at least one embodiment. At block 530, the AP prepares to transmit the beacon frame.

[0117] At block 532, the AP checks whether the RAW-cmc method is supported and enabled before transmitting the beacon frame. If RAW-cmc is not supported or is disabled, the process 500c may proceed directly from decision block 532 to block 538 (e.g., via the "N" branch from decision block 532). At block 538, the beacon frame is transmitted by the AP.

[0118] If the AP determines in block 532 that the RAW-cmc method is supported and enabled by the AP, the process 500c may proceed from decision block 532 (e.g., via the "Y" branch from decision block 532) to an additional decision block 534. In decision block 534, the AP further checks whether enough time has passed since the last RAW used for self-calibration. For example, a maintenance interval of 60 seconds may be set as the minimum time interval between two RAW-cmc events.

[0119] If the AP determines that not enough time has passed since the last RAW-cmc calibration period, for example, if the time since the last RAW-cmc calibration period is less than 60 seconds, process 500c can proceed from additional decision block 534 via the “N” branch from decision block 534 directly to block 538, where the AP transmits a beacon frame.

[0120] If the AP determines in block 534 that sufficient time has passed since the last RAW-cmc calibration period, the process 500c may proceed to block 536 (e.g., via the "Y" branch from decision block 534).

[0121] According to this embodiment, in block 536, the AP inserts an RPS IE in the beacon frame with a single RAW slot in the RAW assigned to the preselected calibration AID.

[0122] After inserting the RPS IE into the beacon frame, the AP may proceed to block 538 and transmit the beacon frame including the RPS IE over the wireless medium.

[0123] FIG. 5D is a flow diagram of a process 500d of RAW-cmc implemented by a STA based on receiving a beacon frame from an AP that includes an RPS IE indicating an AID, according to some embodiments.

[0124] For example, according to one embodiment, the STA receives a beacon frame including an RPS IE indicating an AID at block 540. In particular, the STA receives the beacon frame including the RPS IE at block 540 and then performs one or more of the following checks: Check if the STA supports the RAW-cmc method at block 542; Check if the AID communicated in the RPS IE matches a pre-selected calibration AID advertised by the AP during association at block 544; Check if the STA requires calibration at block 546.

[0125] If the STA determines a “No” answer at any of decision blocks 542, 544, or 546, process 500d exits the decision tree via the respective “N” branch from decision block 542, 544, or 546 and proceeds directly to block 549. At block 549, the STA is configured to comply with (e.g., adhere / obey) the rules specified in 802.11ah regarding STA behavior during a RAW period or window.

[0126] If the STA determines that it supports the RAW-cmc method (e.g., the "Y" branch from decision block 542), determines that the AID in the RPS IE matches a preselected calibration AID (e.g., the "Y" branch from decision block 544), and determines that the STA requires calibration (e.g., the "Y" branch from decision block 546), the STA may proceed to block 548 of process 500d.

[0127] At block 548, the STA may be configured to perform PHY calibration utilizing the reserved quiet medium during the RAW specified in the RPS IE of the received beacon frame, e.g., in the same or similar manner as described above. For example, at block 548, the STA may perform PHY calibration using a RAW that is the same as or similar to the RAW 430 reserved for device calibration in example 400 of FIG.

[0128] In block 549 of FIG. 5D, even if the STA does not perform self-calibration during RAW, it does not transmit on the wireless medium to comply with the RAW rules.

[0129] 5E is a flow diagram of an example process 500e implemented by a STA to perform calibration using a silent medium, according to some embodiments. In particular, the flow diagram 500e of FIG. 5E illustrates an example scenario in which a STA may perform PHY calibration outside of a RAW scheduled by the RAW-cmc method, according to at least one embodiment.

[0130] At block 550, the STA determines that it requires a silent medium to perform calibration. At block 552, the process 550e includes determining or checking whether the RAW-cmc method is supported when the STA requires a silent medium for self-calibration. If the STA supports RAW-cmc (e.g., the "Y" branch from decision block 552), the process may proceed to block 554.

[0131] At block 554, process 550e includes determining whether the STA can wait (e.g., delay) performing the calibration until the next RAW-cmc calibration event or period (e.g., the next RAW-cmc service period). For example, the STA can determine whether it can wait to perform the calibration based on the time elapsed since the last RAW-cmc service, and / or the STA can make the determination of block 554 based on the presence of some external event that requires an immediate calibration service. The external event may be observed at the PHY, such as an observation that the noise floor has risen above a certain threshold.

[0132] If the STA does not support the RAW-cmc method described herein (e.g., the "N" branch from decision block 552), the STA may proceed directly from decision block 552 to block 556. In block 556, the STA reserves a quiet medium for self-calibration using a conventional method. That is, in block 556, the STA sends a CTS-To-Self frame to the AP to request a quiet medium for calibration. Otherwise, the STA waits for the next beacon frame that includes an RPS IE advertising a reserved RAW for device calibration and calibrates its PHY parameters in the next reserved RAW.

[0133] For example, if the STA supports the RAW-cmc method described herein (e.g., the "Y" branch from decision block 552) but can wait to perform calibration until the next RAW-cmc service period (e.g., the "Y" branch from decision block 554), process 500e ends with the STA skipping execution of block 556, and no CTS-To-Self is sent by the STA to silence the media during the current period, and no calibration is performed by the STA.

[0134] FIG. 5F is a flow diagram of a wireless communication process 500f for performing RAW-cmc using a dynamic interval update mode implemented by an AP to respond to changing conditions that may require a STA to calibrate more frequently, in accordance with some embodiments.

[0135] In particular, Figure 5F illustrates an optional dynamic interval update mode that may be implemented in an AP to respond to changing conditions. For example, in at least some embodiments, process 500f of Figure 5F may correspond to a dynamic interval update mode that may be used in response to detection by the AP of changed conditions that indicate a need for a STA to perform calibration more frequently.

[0136] In one illustrative example, the dynamic maintenance interval may be initially set as (e.g., initialized to) a preset or pre-configured value. The initial value of the dynamic maintenance interval may be used to determine the minimum time interval between two (e.g., consecutive) RAW-cmc events. In some aspects, the dynamic maintenance interval may be adaptively adjusted. A shorter dynamic maintenance interval indicates that the AP will schedule RAWs for device calibration more frequently.

[0137] As shown, at block 560, process 500f may begin with the AP receiving a CTS-To-Self frame from the STA. In some aspects, the CTS-To-Self frame received by the AP from the STA at block 560 of FIG. 5F may correspond to one of the multiple CTS-To-Self frames shown on the wireless medium 610 of FIG. 6. The CTS-To-Self frame may be a normal frame (e.g., a non-isolated frame) that is the same as or similar to one or more of the normal / non-isolated CTS-To-Self frames 612 of FIG. 6. In some cases, the CTS-To-Self frame may be an isolated frame that is the same as or similar to one of the isolated CTS-To-Self frames 615 of FIG. 6.

[0138] At block 562, the AP checks whether the CTS-To-Self frame is orphaned. For example, the AP can be configured to determine whether the received CTS-To-Self frame of block 560 is a normal / non-orphaned frame or an orphaned frame. For example, the AP can analyze the time in the CTS-To-Self frame to determine whether it is less than a valid frame time based on the implementation where the CTS-To-Self frame is considered orphaned if the CTS-To-Self time is less than a valid frame time.

[0139] If the CTS-To-Self time is less than the valid frame time, then in block 562 the AP determines that the CTS-To-Self frame is isolated and proceeds via the "Y" branch from decision block 562 to additional decision block 563.

[0140] If the CTS-To-Self time is greater than or equal to the valid frame time (e.g., if the CTS-To-Self time is greater than or equal to / greater than the valid frame time), then at block 562 the AP determines that the CTS-To-Self frame is not orphaned and proceeds directly to block 566 via the "N" branch from decision block 562. At block 566, process 500f ends by not updating the RAW-cmc calibration period. For example, if the CTS-To-Self time is greater than the valid frame time, the dynamic maintenance interval (e.g., the RAW-cmc calibration period) can remain unchanged because the AP can wait and see if traffic occurs after the CTS-To-Self frame.

[0141] In block 563, the AP may be configured to further check whether the isolated CTS-To-Self frame has a partial AID that matches a device in the BSS. If the CTS-To-Self partial AID does not match a device in the BSS, the AP may proceed via the "N" branch from decision block 563 directly to block 566 without updating the RAW-cmc calibration period as described above. In block 566, if the CTS-To-Self partial AID does not match any device in the BSS, the dynamic maintenance interval remains unchanged.

[0142] If the isolated CTS-To-Self frame has a partial AID that matches a device in the BSS, the AP may proceed via the "Y" branch from decision block 563 to an additional decision block 564.

[0143] At block 564, if the CTS-To-Self Partial AID matches a device in the BSS (e.g., "Y" at previous decision block 563), the AP may determine whether the average time between isolated CTS-To-Self frames is less than the current dynamic maintenance interval. The average time between isolated CTS-To-Self frames may be determined based on multiple CTS-To-Self frames received by the AP. For example, each CTS-To-Self frame received at example block 560 of process 500f and / or included in multiple isolated CTS-To-Self frames 615 of FIG. 6.

[0144] If the average time between isolated CTS-To-Self frames is not less than the current RAW-cmc calibration period, the AP may proceed directly to No Update of RAW-cmc Calibration Period block 566 via the "N" branch from decision block 564. In block 566, the dynamic maintenance interval remains unchanged based on the average time between isolated CTS-To-Self frames being greater than the current dynamic maintenance interval.

[0145] Otherwise, if the average time between isolated CTS-To-Self frames is greater than or equal to the length of the current RAW-cmc calibration period, the AP proceeds via the "Y" branch from decision block 564 to an additional decision block 565.

[0146] At block 565, the AP further checks whether the length of the dynamic maintenance interval exceeds a lower threshold. The lower threshold may be a predefined threshold limit / value associated with one or more APs and corresponding STAs. In some aspects, the dynamic maintenance interval cannot be decreased if the lower threshold has already been reached. Thus, if the dynamic maintenance interval is already at the lower threshold, the AP may proceed via the "N" branch from decision block 565 to block 566 without updating the RAW-cmc calibration period. At block 566, the dynamic maintenance interval remains unchanged based on the current value already reaching the predefined lower threshold.

[0147] Otherwise, if the RAW-cmc calibration period exceeds the predetermined lower threshold, the AP may proceed via the "Y" branch from decision block 565 to block 568. At block 568, the AP decreases the dynamic maintenance interval.

[0148] In some embodiments, flow diagram 500f in FIG. 5F corresponds to an example illustrating a response to increasing the frequency of calibration by decreasing the calibration period, while flow diagram 500g shown in FIG. 5G corresponds to and illustrates an optional dynamic interval update mode that may be implemented in an AP to gradually increase the dynamic maintenance interval, at least in some embodiments.

[0149] In particular, FIG. 5G is a flow diagram of a wireless communication process 500g that may be implemented by an AP to perform RAW-cmc using a dynamic interval update mode to gradually increase the dynamic maintenance interval in accordance with some embodiments.

[0150] At block 572, process 500g may include an AP RAW-cmc calibration timer being triggered or started at the AP. For example, at block 574, the AP may analyze the previous update interval to check or determine whether the dynamic maintenance interval has decreased in any or more of the past 10 intervals. In other words, starting the AP maintenance update timer at block 572 may correspond to having the AP determine at block 574 whether the RAW-cmc calibration period has decreased in any of the previous 10 intervals.

[0151] In some embodiments, the AP maintenance update timer of block 572 may be set to determine a rate at which to update the dynamic maintenance intervals of the STAs associated with the AP. In one illustrative example, the dynamic maintenance interval may be increased in length based on a determination by the AP that the dynamic maintenance interval has not decreased for any of the past ten intervals.

[0152] In response to determining that the RAW-cmc calibration period has not decreased for the past 10 update intervals, the AP may proceed via the "Y" branch from decision block 574 to block 578. In block 578, the dynamic maintenance interval is increased, thereby increasing the RAW-cmc calibration period.

[0153] If the RAW-cmc calibration period has decreased in at least one of the last ten update intervals, the AP may instead proceed via the "N" branch from decision block 574 to block 576. No update to the RAW-cmc calibration period is made in block 576. In some other embodiments, for device calibration, the AP may use a fixed maintenance interval to adjust the RAW.

[0154] FIG. 7 is a flow diagram of an example process 700 for wireless transmission over a wireless local area network (WLAN), according to some embodiments. The process 700 may be performed by a wireless communication device, such as a Wi-Fi station (STA). At block 702, the process 700 includes receiving a beacon frame including a restricted access window (RAW) parameter set (RPS) information element (IE). At block 704, the process 700 includes determining whether an association identity (AID) indicated in the RPS IE of the received beacon frame matches a calibration AID associated with the STA. At block 706, the process 700 includes determining a RAW based on the RPS IE. At block 708, the process 700 includes scheduling a RAW clear media calibration (RAW-cmc) event in the RAW based at least in part on determining that the AID indicated in the RPS IE matches the calibration AID. At block 710, the process 700 includes performing a calibration of the STA as scheduled using a scheduled RAW-cmc event in the RAW.

[0155] 8 illustrates a computing device architecture 800 of a computing device that can implement one or more of the techniques described herein. In some examples, the computing device can include a mobile device, a wearable device, an augmented reality device (e.g., a virtual reality (VR) device, an augmented reality (AR) device, or a mixed reality (MR) device), a personal computer, a laptop computer, a video server, a vehicle (or a computing device in a vehicle), or other device. The components of the computing device architecture 800 are shown in electrical communication with each other using a connection 805, such as a bus. The computing device architecture 800 includes a processing unit 810 and computing device connections 805 that couple various computing device components, including a computing device memory 815, such as a read only memory (ROM) 820 and a random access memory (RAM) 825, to the processor 810.

[0156] The computing device architecture 800 may include a cache of high-speed memory that is directly connected to the processor 810, close to the processor 810, or integrated as part of the processor 810. The computing device architecture 800 may copy data from the memory 815 and / or the storage device 830 to the cache 812 for quick access by the processor 810. In this manner, the cache may provide a performance boost that avoids delays in the processor 810 while waiting for data. These and other engines may control or be configured to control the processor 810 to perform various operations. Other computing device memories 815 may also be used. The memory 815 may include multiple different types of memory with different performance characteristics. The processor 810 may include any general-purpose processor, hardware or software services (e.g., service 1 832, service 2 834, and service 3 836) stored in the storage device 830 that are configured to control the processor 810, and dedicated processors where software instructions are built into the processor design. The processor 810 may be a self-contained system that includes multiple cores or processors, buses, memory controllers, caches, etc. Multi-core processors may be symmetric or asymmetric.

[0157] To enable user interaction with the computing device architecture 800, the input device 845 may represent any number of input mechanisms, such as a microphone for voice, a touch-sensitive screen for gesture or graphic input, a keyboard, a mouse, motion input, speech, etc. The output device 835 may be one or more of many output mechanisms known to those skilled in the art, such as a display, projector, television, speaker device, etc. In some cases, a multimodal computing device may enable a user to provide multiple types of input to communicate with the computing device architecture 800. The communication interface 840 may generally control and manage user input and computing device output. There is no limitation to operation with a particular hardware configuration, so the basic functions herein may be easily replaced with improved hardware or firmware configurations developed.

[0158] The storage device 830 is a non-volatile memory and may be a hard disk or other type of computer readable medium capable of storing data accessible by a computer, such as a magnetic cassette, a flash memory card, a solid state memory device, a digital versatile disk, a cartridge, RAM, ROM, and hybrids thereof. The storage device 830 may include services 832, 834, 836 for controlling the processor 810. Other hardware or software modules or engines are also contemplated. The storage device 830 may be connected to the computing device connections 805. In one aspect, a hardware module that performs a particular function may include software or processor readable code stored on a computer readable medium in association with the hardware components necessary to perform that function, such as the processor 810, the connections 805, the output devices 835, etc.

[0159] The term "device" is not limited to one or a particular number of physical objects (such as a smartphone, a controller, a processing system, etc.) As used herein, a device may be any electronic device with one or more components capable of implementing at least a portion of the present disclosure.

[0160] Each aspect may be described as a process or method that is depicted as a flowchart or data flow diagram. Although a flowchart may depict operations as a sequential process, many of the operations may be performed in parallel or simultaneously. Additionally, the order of operations may be re-arranged. A process terminates when operations are completed, but may include additional steps not included in the diagram. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination may correspond to a return of the function to the calling function or to the main function.

[0161] The techniques described herein may also be implemented in electronic hardware, computer software, firmware, or any combination thereof. Such techniques may be implemented in any of a variety of devices, such as general purpose computers, wireless communication device handsets, or integrated circuit devices having multiple uses, including applications in wireless communication device handsets and other devices. Any features described as modules or components may be implemented together in an integrated logic device, or separately as separate but interoperable logic devices. If implemented in software, the techniques may be realized at least in part by a computer-readable data storage medium comprising program code including instructions that, when executed, perform one or more of the methods described above.

[0162] The program code may be executed by a processor, which may include one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Such a processor may be configured to perform any of the techniques described in this disclosure. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may be implemented as a combination of computing devices.

Claims

1. A method for managing calibration of a station (STA) in a wireless communication network, comprising: receiving a beacon frame including a restricted access window (RAW) parameter set (RPS) information element (IE); determining whether an Association Identity (AID) indicated in an RPS IE of the received beacon frame matches a calibration AID associated with the STA; determining a RAW based on the RPS IE; scheduling a RAW clear media calibration (RAW-cmc) event within the RAW based at least in part on a determination that the AID indicated in the RPS IE matches the calibration AID; and performing a scheduled calibration of the STA using a scheduled RAW-cmc event in the RAW. method.

2. The method of claim 1 , wherein the RPS IE indicates information corresponding to one or more of a start time associated with the RAW, a slot duration associated with the RAW, or a number of slots associated with the RAW.

3. 2. The method of claim 1, wherein to perform calibration of the STA on a schedule, the STA calibrates one or more physical (PHY) layer parameters in the RAW-cmc event during the RAW.

4. the RAW-cmc event is scheduled based on a further determination that the STA supports RAW-cmc; The method of claim 1 , further comprising restricting any transmissions of a STA during the RAW based on a determination that the STA does not support RAW-cmc.

5. determining whether the STA requires calibration in response to determining that the AID indicated in the RPS IE matches the calibration AID; scheduling the RAW-cmc event based on a determination that the STA requires calibration; and skipping the scheduling of the RAW-cmc event based on a determination that the STA does not require calibration. The method of claim 1.

6. The method of claim 5 , wherein whether the STA requires calibration is determined based on an elapsed time since the STA's last silence media calibration.

7. 6. The method of claim 5, wherein whether the STA requires calibration is determined based on one or more external events observed by the STA at a physical (PHY) layer associated with the STA.

8. The method of claim 1 , wherein the calibration AID is set by an access point (AP) associated with the STA, and the calibration AID comprises a static value set within a higher range of allowed AIDs.

9. transmitting, by the STA, an association request to associate with an access point (AP) in the wireless communication network; receiving an association response from the AP, the association response including the calibration AID and a RAW-cmc vendor IE indicating a calibration period of the RAW-cmc event; and storing, by the STA, a calibration AID and a calibration period indicated in the RAW-cmc vendor IE. The method of claim 1.

10. The STA utilizes a silence medium for calibration; The method comprises: determining whether the STA supports RAW-cmc; determining, based on a determination that the STA supports RAW-cmc, whether the STA can defer performing a calibration until a next RAW-cmc event; and in response to determining that the STA does not support RAW-cmc or that the STA cannot delay performing calibration until the next RAW-cmc event, transmitting, by the STA, a Clear To Send to Self (CTS-To-Self) frame to reserve silence media for calibration, and performing calibration of the STA using the reserved silence media corresponding to the CTS-To-Self frame. The method of claim 1.

11. 2. The method of claim 1, wherein the STA restricts any transmissions during the RAW based on a determination that the AID indicated in the RPS IE does not match a calibration AID stored by the STA and does not match an AID associated with the STA.

12. A station (STA) connected to a wireless communication network, the STA comprising: A receiver and a transmitter; a processor communicatively coupled to the receiver and the transmitter; one or more memory banks communicatively coupled to the processor for storing processor-readable code; The processor readable code, when executed by the processor in conjunction with the receiver and transmitter, The processor, receiving a beacon frame including a restricted access window (RAW) parameter set (RPS) information element (IE); determining whether an Association Identity (AID) communicated in an RPS IE of the received beacon frame matches a calibration AID stored in the STA; determining a RAW according to the RPS IE; If the AID communicated in the RPS IE matches the calibration AID, scheduling a RAW clear media calibration (RAW-cmc) event during the RAW; Calibrating at the RAW-cmc event as scheduled or restricting any transmissions during the RAW; Station (STA).

13. A method for managing calibration of a plurality of stations (STAs) in a wireless communication network, comprising: determining, by an access point (AP) associated with the plurality of STAs, an elapsed time since a last restricted access window (RAW) clear medium calibration (RAW-cmc) event on a wireless medium; inserting an RPS information element (IE) including a RAW slot in a RAW associated with a calibration association identity (AID) included in a beacon frame generated by the AP based on the elapsed time being greater than a predetermined threshold time value; transmitting the beacon frame from the AP to one or more stations (STAs) in the wireless communication network over a wireless medium, the wireless medium being reserved as a silent medium during a RAW slot in the RAW for the one or more STAs to perform calibration; method.

14. receiving an association request from a station (STA) in the wireless communication network; inserting a RAW-cmc vendor IE including the calibration AID and a calibration period into an association response generated by the AP in response to an association request received from the STA; and sending an association response with the RAW-cmc vendor IE to the STA. The method of claim 13.

15. The method of claim 13 , wherein the RPS IE indicates information corresponding to one or more of a start time associated with a RAW, a slot duration associated with the RAW, or a number of slots associated with the RAW.

16. receiving a Clear To Send to Self (CTS-To-Self) frame from a station (STA) indicating a request for calibration on a quiet medium; and (c) reserving a wireless medium for the STA to perform calibration according to the CTS-To-Self frame, the reserved wireless medium being inaccessible to any data transfer during the reserved time. The method of claim 13.

17. comparing the time since the last RAW-cmc event with a dynamic maintenance interval obtained by the AP; and transmitting the beacon frame based on a determination that an elapsed time since the last RAW-cmc event is greater than the dynamic maintenance interval. The method of claim 13.

18. The method of claim 17 , further comprising adaptively updating the dynamic maintenance interval.

19. Adaptively updating the dynamic maintenance interval includes: receiving an isolated CTS-To-Self frame by the AP; determining, by the AP, that the CTS-To-Self Partial AID matches a device in the wireless communication network; In response to determining, by the AP, that an average time between isolated CTS-to-Self frames is less than the dynamic maintenance interval and the dynamic maintenance interval is greater than a predetermined lower limit, decreasing the dynamic maintenance interval.

20. The method of claim 18.

20. The method of claim 19 , wherein the isolated CTS-To-Self frame is associated with a CTS time that is shorter than a valid frame time associated with the AP.

21. Adaptively updating the dynamic maintenance interval includes: determining that an update timer associated with the AP has expired; determining, by the AP, whether the dynamic maintenance interval has decreased in any of the past 10 update intervals based on expiration of the update timer; extending the dynamic maintenance interval based on a determination that the dynamic maintenance interval has not decreased during any of the past ten update intervals; or and using an unchanged dynamic maintenance interval value based on a determination that the dynamic maintenance interval has decreased in any of the last ten update intervals.

20. The method of claim 18.

22. An access point (AP) connected to a wireless communication network, the AP comprising: A receiver and a transmitter; a processor communicatively coupled to the receiver and the transmitter; one or more memory banks communicatively coupled to the processor for storing processor-readable code; The processor readable code, when executed by the processor in conjunction with the receiver and transmitter, Checking whether enough time has passed since the last Limited Access Window (RAW) Clear Media Calibration (RAW-cmc) event; inserting a RAW Parameter Set (RPS) information element (IE) into a beacon frame that includes a RAW slot assigned to a calibration association identity (AID) if a sufficient amount of time has elapsed since the last RAW-cmc event; transmitting the beacon frame by the transmitter to one or more stations (STAs) in the wireless communication network; is set to schedule the current RAW-cmc event for device calibration; Access point (AP).

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