SYSTEMS, APPARATUS AND METHODS FOR ENHANCING BROADCAST SERVICES IN WIRELESS LOCAL AREA NETWORKS

Disclosed herein are apparatus and methods for enhancing broadcast services in wireless local area networks (WLAN). Embodiments provide systems, apparatus and methods that ensure a mobile transceiver (STA) receiving a broadcast stream, receives the stream in a continuous and seamless manner as the STA moves from an area covered by a first AP into an area covered by a second AP. Further embodiments provide systems, apparatus and methods by which an Access Point acquires channel sounding information from one or more sensor devices comprising transceiver stations (STA) to provide enhanced broadcast channel condition services to STA operating within the AP coverage area.

BACKGROUND

Wireless networks include mobile, portable and fixed stations (STA) with increasingly diverse capabilities and usage profiles. For example, in an Internet of Things (IoT) environment, wireless Internet access point (AP) may serve a large number of small limited capability sensor STAs. Such sensor devices typically relay relatively small amounts of various sensed environmental parameters to remote receivers via wireless uplinks to an AP. At the same time an AP may also serve Internet access to STAs comprising wireless laptops, PDAs, mobile phones, etc. These devices can be equipped with multiple transceivers configured for wireless communication in one or more radio frequency bands corresponding to one or more IEEE 802.11 standards: 900 MHz (802.11ah), 2.4 GHz (802.11b/g/n/ax), 3.6 GHz (802.11y), 4.9 GHz-5 GHz (802.11j-WLAN), 5 GHz (802.11a/h/j/n/ac/ax), 5.9 GHz (802.11p), 6 GHz (802.11ax) and 60 GHz (802.11ad/ay.

An AP typically provides a wide range of services to wireless STAs operating within the AP broadcast range. For example, an AP can broadcast streams of media content to laptop, PDA and smartphone STA within its broadcast range. The AP can also broadcast channel conditions to STAs trying to connect to the AP as well as to STAs already associated with an AP. Therefore, it is important for an AP to be capable of ascertaining channel conditions for its broadcasts. It is also important for an AP to be capable of supporting a STA receiving a broadcast stream as the STA transitions from the area covered by the AP to an area covered by a different AP. Accordingly a need exists for an AP to provide enhanced broadcast services to STAs operating in wireless local area networks (WLANs).

SUMMARY

Disclosed herein are apparatus and methods for enhancing broadcast services in wireless local area networks (WLAN). Embodiments provide systems, apparatus and methods that ensure a mobile transceiver (STA) receiving a broadcast stream, receives the stream in a continuous and seamless manner as the STA moves from an area covered by a first AP into an area covered by a second AP. Further embodiments provide systems, apparatus and methods by which an Access Point device acquires channel sounding information from one or more sensor devices comprising transceiver stations (STA) to provide enhanced broadcast channel condition services to STA operating within the AP coverage area.

DETAILED DESCRIPTION

In an embodiment, the base station114aand the WTRUs102a,102b,102cmay implement a radio technology such as NR Radio Access, which may establish the air interface116using NR.

The RAN104may be in communication with the CN106, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs102a,102b,102c,102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN106may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown inFIG.1A, it will be appreciated that the RAN104and/or the CN106may be in direct or indirect communication with other RANs that employ the same RAT as the RAN104or a different RAT. For example, in addition to being connected to the RAN104, which may be utilizing a NR radio technology, the CN106may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

The CN106shown inFIG.1Cmay include a mobility management entity (MME)162, a serving gateway (SGW)164, and a packet data network (PDN) gateway (PGW)166. While the foregoing elements are depicted as part of the CN106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

The CN106may facilitate communications with other networks. For example, the CN106may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN106and the PSTN108. In addition, the CN106may provide the WTRUs102a,102b,102cwith access to the other networks112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In one embodiment, the WTRUs102a,102b,102cmay be connected to a local DN185a,185bthrough the UPF184a,184bvia the N3 interface to the UPF184a,184band an N6 interface between the UPF184a,184band the DN185a,185b.

An Enhanced broadcast service (eBCS or EBCS) as used herein is any broadcast service that enhances transmission and reception of broadcast data in an infrastructure BSS where there is an association between an AP (broadcast transmitter) and one or more STA clients (broadcast receivers), and also in situations in which there is not an association between an AP server and AP clients.

Channel sensing as used herein is a mechanism to detect channel occupancy or predict future traffic in wireless networks that use carrier sense multiple access with collision avoidance (CSMA/CA). For example, in a virtual channel sensing technique, a timer mechanism is used that is based upon durations of previous frame transmission in order to predict future traffic in the channel. A network allocation vector (NAV) is used as a counter that counts down to zero. The maximum NAV duration is the transmission time required by a frame, which is the time for which the channel will be busy. At the start of transmission of a frame, the NAV value is set to its maximum. A non-zero value indicates that the channel is busy, and thus the STA does not contend for the wireless medium. When the NAV value decrements to zero, that indicates that the channel may be free and the STA can then contend for the wireless medium.

Sensing procedure as used herein is a series of steps or acts by which a wireless device performs channel sensing for the purpose of measuring some parameter of a channel.

Sensing session as used herein is a temporary and cooperative exchange of signals or information between two or more devices to perform channel sensing. A sensing session may be further defined by operational parameters associated with that sensing session. A sensing session can comprise any one or more of the following processes: setup, measurement, reporting, and/or termination. Accordingly, a STA implementing sensing according to the disclosed embodiments is configured to perform one or more of the following sensing functions: setup, measurement, reporting and or termination.

A sensing initiator is a STA that initiates a sensing session.

A sensing responder is a STA that participates in a sensing session initiated by a sensing initiator.

A sensing transmitter is a STA that transmits protocol packet data units (PPDUs) corresponding to a sensing measurement or a sensing session.

A sensing receiver is a STA that receives PPDUs sent by a sensing transmitter and performs sensing measurement acts as part of a sensing session.

In the above definitions a STA can assume more than one role in a sensing session. For example, in a given session a first STA can serve as a sensing transmitter as a well as a sensing receiver. In another session a first STA can serve as a sensing transmitter and a second STA can serve as a sensing transmitter. Not all STAs in a BSS necessarily participate in every sensing sessions. In some instances, no STA will serve as a sensing transmitter or a sensing receiver.

In some embodiments, EBCS APs broadcast data streams on a downlink to non-AP STAs. In some embodiments, an AP provides broadcast services (i.e. data streams) to associated STA as well as unassociated STA. In some embodiments, an AP provides broadcast services to up to 300 non-AP STA. A non-AP STA can be a low cost non AP STA that is only capable of receiving the AP broadcast data stream but is not capable of transmitting directly to the AP.

The embodiments described herein may be found in a variety of applications. For example, an AP broadcasts video streams to STAs in a sports stadium. In another example application, an AP broadcasts streams of safety information to vehicles. In some embodiments, an AP broadcasts data provided by sensors on an uplink to the AP. Other applications include broadcasts of museum information, multilingual broadcasts and Event Producer Information and Content Broadcasting.

An AP may automatically provide EBCS data streams, or provide particular EBCS traffic streams on a routine or scheduled basis depending on a broadcast schedule or configuration. For some data streams, a STA in an AP coverage area need not be associated with the AP to receive the broadcast data stream from the AP. For some data streams, a STA need not be registered with or request the AP to receive the broadcast data stream. Thus, an AP may not have records of all STAs receiving its broadcast data streams in a scenario where the AP is also broadcasting data streams to unassociated STAs and/or unregistered STAs. In those instances, a STA need not request an EBCS data stream to receive it. In other instances, an AP provides one or more EBCS traffic streams only upon request or register of one or more STAs.

In some cases, one or more EBCS data streams are always provided, depending on the operators' configuration, while other EBCS data streams are provided upon request from a STA. For an EBCS data stream that is transmitted by the AP upon request or register from a STA, mobility support may be needed for a STA that is currently receiving an EBCS data stream and is predicted to move outside a broadcast coverage range of the current AP. This scenario raises an issue as to how to provide an efficient mechanism to ensure that an EBCS traffic stream can be continued seamlessly upon leaving a coverage area of a first AP and entering the coverage area of a second AP.

An EBCS AP may provide broadcast data streams to STAs that are either associated with the EBCS AP or unassociated with the EBCS AP. Information for EBCS broadcast services provided by an AP may be contained in an EBCS information (Info) frame, which may be broadcasted by the AP. Discovery methods disclosed herein may be used by STAs to discover EBCS services provided by the AP by efficiently discovering the timing of the EBCS Info frame.

In some embodiments, WLAN sensing protocols (e.g., 802.11bf) may support sensing operations by a large number (e.g., thousands) of non-AP STAs, including legacy STAs (e.g. pre 802.11bf devices), that have certain sensing capabilities. The sensing operations may include various sensing phases including setup phase, measurement phase, reporting phase, and/or termination phase.

In one embodiment, a seamless transition of reception of an EBCS traffic stream by a STA from a first AP to a second AP occurs. The STA receives an EBCS traffic stream from a first AP. The STA is mobile and is leaving the area covered by the first AP and entering an area covered by one or more second APs. The first AP, which is an EBCS AP, may provide information about other EBCS APs that provide the same EBCS data streams that one or more of the EBCS STAs are currently consuming, or information about one or more EBCS data streams that the EBCS AP is currently providing. The first AP may transmit at least one of a beacon, a short beacon, a probe response, a fast initial link setup (FILS) Discovery frame and/or or other management, control, or data frame that includes indications of one or more second APs providing the same or similar EBCS data streams as those provided by the first AP.

In one embodiment, the first AP provides the indications of the one or more second EBCS APs that provide similar or the same EBCS data streams in a Neighbor Report element or a Reduced Neighbor Report element, or a newly designed element. For example, the STA may send a request for a Neighbor Report to the first AP. The first AP sends a Neighbor Report or Reduced Neighbor Report containing information about neighboring APs that are known candidates for the first STA or other STAs to receive the same EBCS data streams as offered by the first AP. The information may include whether the first STA is required to associate with one or more second APs to receive the same EBCS data streams from one or more of the second APs.

In one embodiment, the first AP provides an indication of one or more second EBCS APs that provide the same or similar EBCS data streams by constructing an EBCS Neighbor AP sub-element, which may be included in a Neighbor Report element, Reduced Neighbor Report element, or in a newly designed EBCS Neighbor element, or in any other newly designed element. The EBCS Neighbor AP sub-element may then be transmitted, for example, to a STA.

Referring toFIG.2A, an EBCS Neighbor AP sub-element200includes one or more of the following fields or subfields, a Subelement ID field210, a Length field220, and a Content ID Indication field230. The Subelement ID field210may be used to indicate that the sub-element is an EBCS Neighbor AP sub-element. The Subelement ID field may contain some number of bits that encode a value indicative to a decoder that the subelement is an EBCS Neighbor AP subelement. The Length field220is used to indicate the length of the sub-element. The length field may contain some number of bits that encode a value indicative to a decoder of the length of the subelement. The Content ID Indication field230may be used to indicate one or more content identifiers that are associated with one or more EBCS data streams or content that is provided by the AP. This field may be a bitmap to indicate one or more content IDs for EBCS data streams that the AP is currently broadcasting. The field may provide an explicit indication of each content ID associated with the EBCS traffic streams that the current AP is currently providing.

The EBCS Neighbor AP sub-element may be contained in one or more elements, for example, the Neighbor Report element, or Reduced Neighbor Report element, which may be used to indicate one or more neighboring APs such that the indication of the ID of the APs may be omitted in the EBCS Neighbor AP sub-element.

In another embodiment, the first AP generates neighbor AP information. The first AP may generate a target beacon transmission time (TBTT) information subfield, or a BSS Parameters subfield, to be included in a Neighbor Report element, or in a Reduced Neighbor Report Element, or a newly designed element. In any case, the first AP inserts one or more indicator bits, and sets the bits to “true” or “false” (which may correspond respectively to a value of 1 or 0, or vice versa) to indicate that the AP associated with the neighbor AP information field can support one or more of the data streams or content that is supported by the first AP.

In another embodiment, the indicator bit or bits may be set to “true”, or “1”, to indicate that the AP associated with the neighbor AP information supports one or more, or all, active EBCS data streams or content that is currently provided by the transmitting AP. In another embodiment, the indicator bit or bits may be set to “true” or “1” to indicate that the AP associated with the neighbor AP information supports one or more, or all, EBCS data streams or content, or all EBCS data streams or content that require registration or request, that are currently provided by the transmitting AP. Such indication may be contained in the Reduced Neighbor Report element, or any other element. In one example, the indication is not set for any co-located or co-hosted AP or any non-transmitted basic service set identifier (BSSID) as the transmitting AP.

FIG.2Billustrates an EBCS Neighbor AP element250. The EBCS Neighbor AP element may include one or more of the following fields. Although shown inFIG.2Bas including all fields, this is only for illustration, and any combination of the fields shown may be present in the EBCS Neighbor AP element250. The element ID260is used to indicate that the element is an EBCS Neighbor AP element. The element ID260may contain some number of bits that indicate to a decoder that the element is an EBCS Neighbor AP element250. The Length262is used to indicate the length of the element. The Length262may contain some number of bits that encode a value indicative to a decoder of the length of the EBCS Neighbor AP element250. The AP ID264indicates the AP ID, such as a MAC address of the AP, or a BSSID, or the MAC address of the AP MLD. The AP ID264may contain some number of bits that encode a value indicative to a decoder of the identifiers mentioned. The Operating Class266and the Operating Channel268indicate the operating class and operating channels of the AP, respectively. The Operating Class266and the Operating Channel268fields may contain some number of bits that encode a value indicative to a decoder of the operating class and the operating channel of the AP, respectively. The Content ID Indication270indicates one or more Content IDs that are associated with one or more EBCS data streams transmitted by the AP. This field may also be implemented as a bitmap to indicate one or more content IDs for EBCS data streams that the current transmitting AP provides. Alternatively, the field includes an explicit indication of each content ID. Alternatively, the field is a bitmap indicating which EBCS traffic streams provided by the current AP are supported.

Note that any of the information described above may be present in a sub-element or an element. Any one or more subfield or information provided thereby can be included in any existing or new element, sub-element, control, management, data frame, and/or PHY and MAC header, or any combination thereof.

In some embodiments, a STA may receive a Reduced Neighbor Report and determine to receive EBCS streams from another AP discovered through the Reduced Neighbor Report received in an associated AP's beacon frame.

As mentioned above, when a STA is consuming an EBCS traffic stream from a first AP, the STA may desire to continue consuming the EBCS traffic stream if the STA roams to another AP. An EBCS AP/BSS transition procedure is needed. In one embodiment, an EBCS AP/BSS transition procedure may begin with an EBCS AP broadcasting one or more EBCS data streams. The AP indicates the available EBCS data streams in one or more frames, such as beacon, short beacon, EBCS Info frame, and/or FILS Discovery frames. For example, the AP may transmit a periodic EBCS Info frame, and contained in that frame is information regarding which EBCS traffic streams the AP is providing or transmitting. The EBCS AP may include information about one or more EBCS neighbor APs in one or more elements or frames, including but not limited to, a Neighbor Report element or a Reduced Neighbor Report element, or may transmit a new EBCS Neighbor AP element, frame, or other data structure. For example, an EBCS Neighbor AP element may be included in the Neighbor Report element to indicate an AP's capability to provide all traffic streams, or all active EBCS traffic streams, or any other content that is provided by the current transmitting AP, or to indicate that the AP has capability to provide all, or all active, EBCS traffic streams and/or content that may or may not require a STA to register or request the second AP that are currently provided by the first AP.

An EBCS non-AP STA may consume an EBCS data stream or content that requires the EBCS non-AP STA to register with the AP or to transmit a request via EBCS Content request frames. The EBCS non-AP STA may receive a frame from an EBCS AP that is the transmitter of, or capable of providing, the EBCS traffic stream or content that contains one or more indicators of one or more EBCS Neighbor APs. Such information may be included in a Neighbor Report element, a Reduced Neighbor Report element, or an EBCS Neighbor AP element. The EBCS non-AP STA may use information received regarding EBCS Neighbor APs to register for one or more EBCS data streams or content offered by one or more indicated EBCS neighbor APs. The EBCS non-AP STA may use an EBCS Traffic Stream or Content Request ANQP-element to register for one or more EBCS data streams or content offered by a neighbor AP. Alternatively, an EBCS non-AP STA may use information received from EBCS Neighbor APs to request one or more EBCS data streams or content from one or more indicated EBCS Neighbor APs, for example using an EBCS Traffic Stream or content request frame.

When a registration request made using an EBCS Traffic Stream or a Content Request ANQP-element, or made using an EBCS request including an EBCS Traffic Stream/content Request frame, is unsuccessful, the EBCS AP may respond with an ANQP-element or EBCS Traffic Stream/Content Response frame in which an EBCS Request status bit is set to a value that indicates “fail”. The EBCS AP may, in some embodiments, include EBCS Neighbor AP information in the response frame, such information may be contained in a Neighbor Report element, a Reduced Neighbor Report element, an EBCS Neighbor AP element, which may identify an EBCS Neighbor AP that provides the same EBCS traffic streams or content as requested by the EBCS STA. The EBCS non-AP STA can use the information received about EBCS Neighbor APs to register for one or more EBCS traffic streams or content being transmitted or provided by one or more indicated EBCS Neighbor APs. To do so, a non-AP STA can use a frame containing an EBCS Traffic Stream or Content Request ANQP-element, or the EBCS non-AP STA uses the information received on EBCS Neighbor APs to request one or more EBCS traffic streams or content from one or more indicated EBCS Neighbor APs using an EBCS Traffic Stream or content request frame.

To terminate one or more EBCS traffic streams or content, an EBCS AP may transmit one or more Termination Notice frames indicating that the AP is terminating the transmission of the EBCS traffic stream or content. In some embodiments, the EBCS AP includes EBCS Neighbor AP information in the Termination Notice frame. For example, in a case where the EBCS AP will not extend the transmission of the EBCS traffic streams or content (regardless of any EBCS non-AP STA requests for the extension of the EBCS traffic streams), the EBCS AP sets a negotiation method field to “no negotiation”. The EBCS Neighbor AP information may be inserted in a Neighbor Report element, a Reduced Neighbor Report element, or an EBCS Neighbor AP element, which may be contained in the EBCS Termination Notice, indicating that the EBCS Neighbor AP provides the same EBCS traffic streams or content that the transmitting EBCS AP will terminate. The EBCS non-AP STA then uses information received regarding EBCS Neighbor APs to register for one or more EBCS traffic streams or content. The registration may be achieved using a frame containing an EBCS Traffic Stream or Content Request ANQP-element. Alternatively, the EBCS non-AP STA can use the information received on EBCS Neighbor APs to request one or more EBCS traffic streams or content from one or more indicated EBCS Neighbor APs. The requested EBCS traffic stream or content may be the same or similar to the EBCS traffic stream or content that the STA is presently consuming.

Example techniques for efficient discovery of enhanced broadcasting services (EBCS) are described in the following embodiments. In one embodiment, a fast initial link setup (FILS) Discovery frame may be used for discovery of EBCS services and EBCS traffic streams. For example, referring toFIG.2C, a signal flow diagram2500shows a first EBCS AP2510transmitting an EBCS traffic stream2540to at least one EBCS STA2520that receives the EBCS traffic stream2542. In embodiment, the second EBCS AP2530transmits a FILS Discovery frame2544including an indication that the second EBCS AP2530is an EBCS AP and/or an indication that the AP provides EBCS broadcasting services. For example, the FILS Discovery frame transmitted by an EBCS AP may contain one or more EBCS related fields, such as, but not limited to: an EBCS capability indication, an EBCS Info frame transmission field, and/or an EBCS Info frame transmission (Tx) Countdown field, which will be described in more detail below.

In some embodiments, the EBCS Info frame transmission field and/or the EBCS Info frame TX Countdown field contained in the FILS Discovery frame2544may be one or two bytes in length. The value indicated in the EBCS Info frame transmission field and/or EBCS Info frame TX Countdown field may be in terms of any one of more of the following units: number of target beacon transmission times (TBTTs), number of beacon intervals, number of time units (e.g., TUs), and/or a duration of time (e.g., in terms of microseconds, milliseconds, or other time units). The EBCS Info frame transmission field and/or the EBCS Info frame TX Countdown field indicates, to the EBCS STA2520, information regarding a subsequent transmission of an EBCS Info frame by the second EBCS AP2530, thereby assisting the EBS STA2520to receive the subsequent EBCS Info frame.

In some embodiments, the FILS Discovery frame2544may include an EBCS Info frame transmission field present bit or an EBCS Info Frame Tx Countdown present bit. An EBCS Info frame transmission field present bit, or EBCS Info Frame Tx Countdown present bit, set to encode a value of 1 indicates that the current FILS Discovery frame carrying the bit may contains an EBCS Info Frame Transmission field, and/or an EBCS Info frame Tx Countdown field, respectively. Alternatively, a value encoding 0 may also indicate the same information.

In some embodiments, the FILS Discovery frame2544transmitted by an EBCS AP2530contains an EBCS Parameters element. Table 1 shows a FILS Discovery frame format including an EBCS Parameters element.

TABLE 1FILS Discovery frame format including an EBCS Parameters elementOrderInformationNotes1Category2Public Action3FILS Discovery Information field4Reduced NeighborOne or more Reduced Neighbor Report elements mayReport elementbe present if dot11FILSActivated ordot11ColocatedRNRImplemented is true; otherwise, theyare not present.(11ax)5FILS IndicationThe FILS Indication element may be present ifelementdot11FILSActivated is true; otherwise, it is notpresent.(11ax)6Roaming ConsortiumThe Roaming Consortium element may be present ifelementdot11FILSActivated is true; otherwise, it is notpresent.(11ax)7TIM elementThe TIM element may be present ifdot11HEOptionImplemented is true;otherwise, it is not present.8TWT elementThe TWT element may be present ifdot11HEOptionImplemented is true, otherwise,it is not present. If present, the Broadcastfield of the TWT element is 1.9OPS elementThe OPS element may be present ifdot11HEOptionImplemented is true; otherwise,it is not present.10Transmit PowerOne Transmit Power Envelope element may be presentEnvelope elementfor each distinct combination of values of the MaximumTransmit Power Interpretation subfield and MaximumTransmit Power Category subfield that is supported forthe BSS if both of the following conditions are met:Either dot11VHTOptionImplemented ordot11ExtendedSpectrumManagementImplementedis true.Either dot11SpectrumManagementRequired ordot11RadioMeasurementActivated is true.(e.g., in a 6 GHz HE AP, bothdot11VHTOptionImplemented anddot11SpectrumManagementRequired may be true).11EBCS ParametersThe EBCS Parameters element may be present if theelementtransmitting AP has enabled EBCS. An EBCS Info frameTX Countdown field may be present if the transmittingSTA or AP has dot11EBCSSupportActivated equal totrue. In some embodiments, the EBCS Info frame TXCountdown field may be present if the transmitting STAor AP has dot11EBCSSupportActivated equal to trueand the length of its dot11EBCSContentList is largerthan 0, it is otherwise not present.

The EBCS Parameters element may contain an EBCS Info Frame TX Countdown field, which may indicate the time remaining until the next transmission of an EBCS Info frame by the AP. The value indicated in EBCS Info Frame TX Countdown field may be in terms of any one or more of the following units: number of TBTTs, number of beacon intervals, number of time units (e.g., TUs), and/or a duration of time (e.g., in terms of microseconds, milliseconds, or other time units), as described above.

Still referring toFIG.2C, an EBCS AP that has EBCS enabled, such as the second EBCS AP2530, that transmits a FILS Discovery frame2544, may include an EBCS Parameters element in the FILS Discovery frame2544that it transmits. In embodiments where an AP is not in a multiple BSSID set and has enabled EBCS, the AP may include an EBCS Parameters element in the FILS Discovery frame that it transmits. In embodiments where an AP in a multiple BSSID set corresponding to the transmitted BSSID and has enabled EBCS may include an EBCS Parameters element in the FILS Discovery frame that it transmits.

In other embodiments, an AP or STA that transmits a FILS Discovery frame and has dot11EBCSSupportActivated equal to true may include an EBCS Parameter element in the FILS Discovery frame that it transmits. In other embodiments, an AP that is not in a multiple BSSID set and has dot11EBCSSupportActivated equal to true may include an EBCS Parameters element in the FILS Discovery frame that it transmits. In a multiple BSSID set, the AP corresponding to the transmitted BSSID and has dot11EBCSSupportActivated equal to true may include an EBCS Parameters element in the FILS Discovery frame that it transmits. In either case, the transmitted FILS Discovery frame that is transmitted includes the EBCS Info Frame TX Countdown field in the EBCS Parameters element.

In another embodiment, an AP or STA that transmits a FILS Discovery frame and has dot11EBCSSupportActivated equal to true and the length of its dot11EBCSContentList larger than 0 may include an EBCS Parameter element in the FILS Discovery frame that it transmits. In an embodiment, an AP that is not in a multiple BSSID set and has dot11EBCSSupportActivated equal to true and the length of its dot11EBCSContentList larger than 0 may include an EBCS Parameters element in the FILS Discovery frame that it transmits. In a multiple BSSID set, the AP corresponding to the transmitted BSSID and has dot11EBCSSupportActivated equal to true and the length of its dot11EBCSContentList larger than 0 may include an EBCS Parameters element in the FILS Discovery frame that it transmits. In either case, the transmitted FILS Discovery frame that is transmitted includes the EBCS Info Frame TX Countdown field in the EBCS Parameters element.

Still referring toFIG.2C, once the EBCS STA2520receives the FILS Discovery frame2544from the second EBCS AP2530, using the information contained in the FILS Discovery frame2544, and particularly using the information contained in the EBCS Parameters element carried therein, such as EBCS Info Frame TX Countdown field, the EBCS STA2520may receive an EBCS Info frame2548that is transmitted2550by the second EBCS AP2530. Using the information contained in the EBCS Info frame2550, the EBCS STA2520may then receive a desired EBCS traffic stream2552that is transmitted2554by the second EBCS AP2530. In this embodiment, the EBCS traffic stream2554transmitted by the second EBCS AP2530does not require the EBCS STA2520to be associated in order to receive the transmitted EBCS traffic stream2554.

In some embodiments, though, the EBCS STA2520must associate with the second EBCS AP2530to receive the EBCS traffic stream2554. In this scenario, the EBCS STA2520may request the EBCS data stream using methods described above. In order to facilitate this, an EBCS AP that provides one or more EBCS traffic streams requiring association may include robust security network (RSN) information in the FILS Discovery (FD) RSN Information subfield in the FILS Discovery Information field of the FILS Discovery frame. Accordingly, if a received FILS Discovery frame contains an EBCS Parameter element, then the EBCS STA2520that received the FILS Discovery frame that contains an EBCS Parameter element may determine the beacon interval during which the next EBCS Info frame2550is expected to be transmitted by the second EBCS AP2530.

The EBCS STA2520that receives a FILS Discovery frame2544containing an EBCS Parameters element that includes RSN information in the FILS Discovery RSN Information subfield may use the RSN information to conduct FILS authentication/association2560with the second EBCS AP2530(e.g., using a FILS authentication protocol). The EBCS STA2520will do this if it has determined that the second EBCS AP2530provides one or more desired EBCS traffic streams that require association. The EBCS STA2520may determine that an AP provides one or more desired EBCS traffic streams that require association based on parameters such as SSID, short SSID, or through other means.

In other related embodiments of, a method of enhancing a broadcast service by performing a channel sensing method will now be described. APs typically broadcast beacon signals conveying information to STAs operating within their broadcast ranges. Wireless networks can comprise a large number, e.g., thousands, of non-AP STAs. Non-AP STAs can include a wide variety of sensors operating in an Internet of Things (IoT) environment in which the sensors wirelessly transmit their sensed data to an AP within their transmission ranges. Many of these sensors are suitable for sensing environmental phenomena useful for characterizing a channel in which the non-AP STA and the AP operate. Embodiments of systems, apparatus and methods disclosed and described herein provide an enhanced channel sounding beacon service that provides channel information based on data provided by one or more of these sensor devices to thereby improve the ability of a STA to broadcast accurate reports of channel conditions in its operating area.

In some embodiments, a method includes establishing at least one service period (SP) during which at least one channel sounding procedure is performed. For example, in some embodiments a method includes establishing a first SP and performing one or more channel sounding set up actions within the first SP, then establishing a second SP and carrying out at least one channel measurement action within the second SP, then establishing a third SP and carrying out at least one channel measurement reporting action within the third SP, then establishing a fourth SP and carrying out at least one channel sounding termination action within the fourth SP.

In some embodiments, a measurement action comprises acquiring channel state information (CSI) associated with the channel. For example, a sensing initiator performs one or more actions to collect CSI, or to collect changes in CSI in a particular sensing environment. These actions may include the initiator transmitting one or more trigger frames to a non-AP sensor STA to solicit uplink data from the non-AP sensor STA.

FIG.3illustrates a signal flow of a sensing procedure300according to one embodiment. In the procedure, a sensing initiator AP310is in wireless communication with a first sensing responder STA320and a second sensing responder STA330. the sensing initiator AP310transmits a request to transmit (RTS1)342to the first sensing responder STA320. The first sensing responder STA320transmits a physical protocol data unit (PPDU) carrying a clear to send (CTS)344signal in response to the RTS342. The sensing initiator AP310performs a channel measurement346while the sensing responder STA320transmits the PDDU carrying the CTS344. In some embodiments, the PPDU carrying the CTS344includes a training field that is used by the sensing initiator AP310to measure the CSI. In some embodiments, the training field is used to measure the CSI at another receiver in the vicinity of the sensing initiator AP310. This procedure may then be repeated for the second sensing responder STA330, with another RTS348, and another PPDU carrying a CTS350, where the sensing initiator AP310may measure the channel352.

Thus, embodiments use RTS/CTS frames in a novel way to measure a channel, instead of for use in preparing to transmit data. Therefore, the length of the RTS that the sensing initiator AP transmits may be set to a very small value. In some embodiments, a first RTS may be of sufficient length to cover the time for just one RTS/CTS transmission, or for multiple RTS/CTS transmissions, during which one or more additional STAs perform an action of setting a NAV such that interference is avoided during the measurement time. This is illustrated inFIG.3by the NAV timer360. The NAV timer360, residing in each of the sensing responder STAs, is updated upon receipt of each received message. In some embodiments, CTSs and RTSs are subsequently transmitted so as to set the length of all remaining RTS/CTS transmissions based on the time remaining in the countdown from the initial setting such that the NAV setting from other devices can be set accordingly. Note the “Other message” block shown inFIG.3may be used for signalling additional actions such as terminating sensing.

For some embodiments in which a responding STA is an 802.11bf compliant sensing device, a flag is used, such as a 1-bit indicator provided in the service field of the data field of the RTS. This bit indicates that this RTS is sent as part of a sensing procedure. Thus, the responding STAs will not expect to subsequently receive data from the RTS transmitter, in this case, the sensing initiator. In some embodiments, the sensing initiator and sensing responder are high efficiency (HE) or Extreme High Throughput (EHT) capable devices. In such embodiments, the channel measurement actions may be carried out using an MU-RTS/CTS mechanism, where multi-user (MU) transmissions are utilized.FIG.4illustrates an embodiment of this method.

Referring toFIG.4, a signal flow400according to one embodiment includes a sensing initiator AP410that is HE or EHT capable, and thus MU capable, a first sensing responder STA420and a second sensing responder STA430that are both HE and MU capable, and a legacy third sensing responder STA440that is not HE or MU capable. It is noted that the MU capable devices are described herein as HE or EHT capable devices, but that is not meant to be limiting. Any device that is compliant with future standards that is MU capable is encompassed by the embodiments described herein. The sensing initiator AP410sends a MU-RTS trigger450to the first sensing responder STA420and the second sensing responder STA430soliciting the HE STAs to send CTSs in a MU coordinated transmission on resources indicated in the MU-RTS trigger450. The first sensing responder STA420transmits a first PPDU carrying CTS452in MU resources indicated by the MU-RTS trigger450along with the second sensing responder STA that transmits a second PPDUY carrying CTS454. The training fields in the PPDUs that carry the first and second CTSs (452and454) are then used by the sensing initiator AP410to perform channel measurement456. In some embodiments, such as shown inFIG.4, both HE STAs and legacy STAs exist in a WLAN. Accordingly, in order to measure a channel associated with the legacy STA, the sensing initiator AP410uses a legacy RTS transmission462to solicit a PPDU carrying CTS460from the third, legacy sensing responder STA440. In one embodiment, the legacy RTS transmission462and the PPDU carrying CTS260from the third, legacy sensing responder STA440occur in the same transmission opportunity as the other transmissions described. The method of setting the NAV or length information in the soliciting MU-RTS Trigger frame and in RTS frame, the NAV timer at each STA, and use of the “other message” illustrated and described above with reference toFIG.3may also be applied here to the method illustrated inFIG.4.

In a further embodiment, a target wake time (TWT) sensing method will now be described. Referring toFIG.5, an AP510has two associated STAs, STA1520and STA2530, and the AP510establishes a channel sensing session using TWT procedures. First, the AP510announces its capabilities to perform TWT based sensing within a TWT service period (SP) (not shown in the figure). The announcement is made using any one of: a Beacon frame, a Probe Response frame, a (Re)Association Response frame, or other suitable type of management frame or control frame. Likewise, a non-AP STA or a sensing responder STA announces its capabilities to perform TWT based sensing within an SP using one of: a Probe Request frame, a (Re)Association Request frame or other type of management frame or control frames (also not shown in the figure).

As shown inFIG.5, a non-AP STA520may negotiate with an AP510and acquires a TWT membership by sending a TWT request frame540to the AP510, and receiving from the AP510a TWT response frame542. The non-AP STA510, now in TWT operation, enters an awake state prior to the transmission of a beacon frame544carrying a Broadcast TWT IE546. The STA520determines a Broadcast sensing TWT SP570based on the information in the Broadcast TWT IE546. The AP indicates in TWT IE550, a broadcast TWT start time, a TWT wake duration, an interval between broadcast TWT service periods and support for trigger based TWT procedure.

The Broadcast TWT IE546may also include setup information for the scheduled sensing procedure. For example, in some embodiments the information includes identification of the sensing initiator(s) and sensing responder(s), an indication of sensing measurement type, e.g., CQI, CSI, SINR, Path loss, time of Arrival (TOA), angle of arrival (AOA), angle of departure (AOD). The Broadcast TWT IE546can further indicate parameters of the sensing procedure to be conducted in the broadcast sensing TWT service period, e.g., multi-antenna setting, channel bandwidth setting, sensing measurement resolution, etc. The IE can further indicate a periodicity of the broadcast sensing TWT service period as well as a TWT sensing channel, which may or may not comprise the primary channel(s).

Next, the AP510transmits a trigger frame548, which may be a basic trigger frame, to STAs that are awake in their respective TWT. STAs scheduled for a TWT (STA 1520and STA 2530) respond with an indication of their awake status and readiness to participate in sensing procedures. For example, STA1520and STA2530each transmit a QoS null frame550(or a PS-Poll frame or an NDP packet). In some embodiments, the AP and STAs exchange frames, e.g., an NDPA frame, an NDP frame, an NDP trigger frame, a BFRP trigger frame, a BF report frame or any other frame suitable for a particular sensing procedure during the sounding exchanges580phase of the sensing TWT SP570. A sensing broadcast TWT ID may be used in some embodiments to uniquely identify a sensing TWT SP. A STA may go back to doze state after the scheduled TWT.

In some embodiments, an AP advertises TWT SP parameters and AP updated information in Beacon frames. A non-AP STA transmits a TWT response frame to negotiate the TWT SP parameters. In some embodiments, the AP terminates a periodically occurring sensing TWT SP by transmitting a broadcast TWT IE that indicates the termination of the sensing TWT.

In another embodiment, referring toFIG.6, a signal flow600, similar to the procedure described above with reference toFIG.4, includes a sensing initiator AP610transmitting an MU-RTS (trigger) frame650to solicit STAs that are capable of transmitting Trigger Based (TB) PPDUs (i.e. a first MU capable sensing STA responder STA620, a second MU capable sensing responder STA630, and a legacy sensing responder STA640). The first MU capable sensing responder STA620and the second MU capable sensing responder STA630each transmit respective PPDUs carrying CTS652,654. The sensing initiator AP uses the received PDDU carrying CTS652,654to measure each channel (i.e. a first channel between the sensing initiator AP610and the first MU capable sensing responder STA620, and a second channel between the sensing initiator AP610and the second MU capable sensing responder STA630, or combined channel between the sensing initiator AP610and the MU capable sensing responders STA620and630). The sensing initiator AP610may subsequently transmit one or more legacy RTS frames658to solicit a PPDU carrying a CTS frame660from at least one non-MU capable sensing responder STA640. The sensing initiator AP610may perform channel measurements using the PPDU carrying a CTS frame660transmitted by the at least one non-MU capable (i.e. legacy) sensing responder STA640. In some embodiments, the sensing initiator AP610may send an MU-RTS trigger frame650with the duration field in the medium access control (MAC) header set to (N*2+1)*aSIFSTime+(N+1)*aCTSTime+N*aRTSTime, wherein aSIFSTime is the time duration of Short Interframe Space (SIFS), aCTSTime is the time to transmit a CTS frame, aRTSTIME is the time to transmit a RTS frame, and N is the number of legacy RTS/CTS exchanges following the current MU-RTS/CTS exchange. The MU-RTS trigger frame650may be used to solicit one or more CTS frames from STAs (e.g., HE STAs, EHT STAs, and/or future generations STAs) that can interpret the MU-RTS frames (i.e.620,630for example). The STAs620,630may respond by transmitting a CTS frame652,654on resources as allocated by the MU-RTS trigger frame650and the STAs620,630may set the duration field of the CTS frame652,654to N*2*aSIFSTime+N*aCTSTime+N*aRTSTime.

In another embodiment, referring toFIG.7, a signal flow700, similar to the example described above with reference toFIG.6, includes a PPDU carrying CTS754,756transmission by a first MU capable sensing responder STA720and a second MU capable sensing responder STA730, triggered by a sensing initiator AP710transmitting a MU-RTS trigger752. The MU-RTS trigger752and CTS754,756exchange may be followed by one or more legacy RTS/CTS exchanges760within the same TXOP and/or in a different TXOP. The one or more legacy RTS/CTS exchanges760may be initiated by the sensing initiator AP710to solicit a PPDU carrying a CTS frame764transmitted by a legacy STA740, that may or may not able to understand MU-RTS frames. The sensing initiator AP710may measure the channel766when the CTS frames764are transmitted by the sensing responder STAs740. For each RTS frame762, the duration field in the MAC header may be set to (M*2+1)*aSIFSTime+(M+1)*aCTSTime+(M−1)*aRTSTime if there are M RTS/CTS exchanges following the current RTS/CTS exchange.

In the embodiments described with reference toFIG.6andFIG.7, based on the duration information contained in an MU-RTS frame, a (legacy) RTS frame, and/or a (legacy) CTS frame, other STAs listening on the medium and reading the duration information from those frames may set and/or update their NAV timer so they can defer from accessing the medium for the indicated duration and save power.

In another embodiment, the MU-RTS/CTS exchanges may be followed by one or more MU-RTS/CTS exchanges, which may be followed by one or more RTS/CTS exchanges within the same TXOP and/or in a different TXOP.

In the example procedures described above, the sensing initiator (e.g., AP) may also initiate one or more legacy RTS/CTS exchanges first before transmitting one or more MU-RTS frames to solicit CTS frames from multiple STAs that may be capable of interpreting MU-RTS frames.

In other embodiments, with reference to any of the procedures described hereinbefore, MU-RTS/CTS exchanges may be replaced by buffer status report poll (BSRP)/buffer status report (BSR) exchanges so that the sensing initiator AP may measure the channel over non-overlapping subchannels in the channel when BSR frames are transmitted by sensing responder STAs. In this embodiment, the duration field settings in the BSRP frames may be calculated by (N*2+1)*aSIFSTime+N*aCTSTime+N*aRTSTime+aBSRTime, wherein aBSRTime is the time to transmit an BSR frame, and N is the number of legacy RTS/CTS exchanges following the current BSRP/BSR exchange. The BSRP frame may be used to solicit one or more BSR frames from STAs (e.g., HE STAs, EHT STAs, and/or future generations STAs) that can interpret the BSRP frames. The HE/EHT/future generation STAs may respond to the BSRP frame by transmitting a BSR frame on resources as allocated by the BSRP frame and set the duration field of the CTS frame to N*2*aSIFSTime+N*aCTSTime+N*aRTSTime.

The BSRP/BSR exchanges may be followed by N (N>=0) RTS/CTS exchanges within the same TXOP and/or in a different TXOP. The RTS/CTS exchanges may be initiated by the sensing initiator to solicit CTS frames transmitted by STAs that may or may not able to understand MU-RTS frames. The sensing initiator AP may measure the channel when the CTS frames are transmitted by the sensing responder STAs. For each RTS frame, the duration field in the MAC header may be set to (M*2+1)*aSIFSTime+(M+1)*aCTSTime+(M−1)*aRTSTime if there are M RTS/CTS exchanges following the current RTS/CTS exchange. In any the examples described herein, SIFS nay be used as an example, however other interframe spacings or time durations may be used in place of SIFs.

In another embodiment, the MU-RTS frame (or sensing trigger frame) described in the embodiments above may include a new class of User Info field or Sensing User Info field. For example, the Sensing User Info field may contain resource unit (RU) allocations for a sensing response STA that does not occupy the primary channel(s), which may be used by the sensing initiating AP to measure a particular RU or subchannel. A sensing MU-RTS or sensing trigger frame may include User Info fields that may be used to solicit CTS frames from legacy STAs on subchannels that occupy the primary channel(s), and may include User Info fields to solicit CTS or other sensing frames from STAs such as 802.11bf STAs (or future generation STAs) on subchannels that do not occupy the primary channel(s).

A legacy STA receiving a sensing MU-RTS frame or sensing trigger frame that includes new class of User Info Fields may respond with a (legacy) CTS frame on subchannels that occupy the primary channel, and a STA such as an 802.11bf STA receiving a sensing MU-RTS frame or sensing trigger frame that includes new class of User Info Fields may respond with a CTS frame or other type of sensing frames on subchannels that do not occupy the primary channel as indicated by the received sensing MU-RTS or sensing trigger frame.

In another embodiment, a new Sensing Report Poll frame may be an enhanced version of a trigger frame, such as a BFRP frame or NFRP frame. The Sensing Report Poll frame may contain a Threshold field, for example in the common info field or other part of the Sensing Report Poll frame. The Sensing Report Poll frame may allocate one or more Random Access RUs in its frame body (e.g., using one or more of the User Info fields). A sensing responder STA that has conducted channel measurement may respond to the Sensing Report Poll frame by transmitting channel measurement information and/or CSI on one or more of the allocated random access RUs if the measurement of the channel performed by the sensing responder STA has exceeded the value indicated in the Threshold field included in the received Sensing Report Poll frame.

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. Although the solutions described herein conform to one or more 802.11 specific protocols, it is understood that the solutions described herein are not limited to implementation in 802.11 networks and lend themselves to implementation in other wireless systems as well. Although SIFS is used to indicate various inter frame spacing in the examples of the designs and procedures, all other inter frame spacing such as RIFS, AIFS, DIFS or other agreed time interval could be applied in the same solutions.