BEACONING WITH RANGE EXTENSION

A method of broadcasting a beacon by a relay device in a basic service set, including: receiving an announcement from a first device indicating whether the relay device is to forward a received beacon to a second device; receiving a beacon from the first device; and forwarding the beacon to the second device based upon the announcement.

FIELD OF THE DISCLOSURE

Various exemplary embodiments disclosed herein relate to beaconing with range extension.

SUMMARY

A summary of various exemplary embodiments is presented below.

Various embodiments relate to a method of broadcasting a beacon by a relay device in a basic service set, including: receiving an announcement from a first device indicating whether the relay device is to forward a received beacon to a second device; receiving a beacon from the first device; and forwarding the beacon to the second device based upon the announcement.

Various embodiments are described, further including: receiving a ultra-high reliability (UHR) PHY protocol data unit (PPDU) from the first device that announces the forwarding of the beacon.

Various embodiments are described, wherein the beacon is forwarded after a short interframe space (SIFS) amount of time after an end of the received UHR PPDU.

Various embodiments are described, wherein a SERVICE field of a PPDU carrying the beacon transmitted by the relay device is same as a SERVICE field of the PPDU carrying the beacon received by the second device.

Various embodiments are described, further including: receiving from the first device a multi-user request to send (MU-RTS) frame; sending a clear to send (CTS) frame to the first device; and guaranteeing an interframe space (IFS) accuracy between the PPDU carrying the received beacon and the PPDU carrying the forwarded beacon to be same as the IFS accuracy of the CTS frame and the MU-RTS frame.

Various embodiments are described, further including adjusting a timestamp of the forwarded beacons based upon a timestamp in the received beacon, a length of the beacon, a predefined interframe space (IFS) time, and a number of hops between the first device and the relay device.

Various embodiments are described, wherein the forwarded beacon includes an indication that the forwarded beacon is a forwarded beacon.

Various embodiments are described, wherein the forwarded beacon only carries information of the first device.

Various embodiments are described, further including: sending a broadcast management frame announcing the information of a relay station to the second device.

Various embodiments are described, wherein the forwarded beacon carries information of the first device and the relay device.

Various embodiments are described, wherein forwarding the beacon to the second device using a backoff procedure and a target beacon transmission time (TBTT) of the first device.

Various embodiments are described, wherein forwarding the beacon to the second device using a backoff procedure and a target beacon transmission time (TBTT) of the relay device.

Various embodiments are described, further including: receiving first block acknowledge from the second device indicating that a PHY protocol data unit (PPDU) from the first device was received by the second device; and transmitting a second block acknowledge to the first device indicating that a PHY protocol data unit (PPDU) from the first device was received by the second device.

Further various embodiments relate to a method of determining by a station whether to use a relay station in communication with an access point, including: receiving an ultra-high reliability (UHR) PHY protocol data unit (PPDU) from the access point; determining a first received signal strength indicator (RSSI) of the access point based on the received UHR PPDU from the access point; receiving a PPDU from a first relay station; determining a second RSSI of the first relay station based on the received PPDU from the relay station; and determining whether to use the relay station to communicate with the access point based upon the first RSSI and the second RSSI.

Various embodiments are described, further including: receiving a PPDU from a second relay station; determining a third RSSI of the second relay station based on the received PPDU from the second relay station; and determining whether to use the first relay station or the second relay station to communicate with the access point based upon the second RSSI and the third RSSI.

Further various embodiments relate to a method of broadcasting a beacon by an access point to a relay station in a basic service set, including: sending an announcement to the relay station indicating whether the relay station is to forward a received beacon to a leaf station; sending a multi-user request to send (MU-RTS) frame; receiving a clear to send (CTS) frame from the relay station; and sending a beacon to the relay station.

Various embodiments are described, wherein sending the beacon to the relay station includes sending an ultra-high reliability (UHR) PHY protocol data unit (PPDU) to the relay station that announces forwarding of the beacon.

Various embodiments are described, wherein a SERVICE field of the UHR PPDU is configured to carry the beacon transmitted by the access point.

Various embodiments are described, further including: receiving a block acknowledge from the relay station indicating a reception of the UHR PPDU by the relay station.

Various embodiments are described, further including: receiving block acknowledge from the relay station indicating a reception of the UHR PPDU by the relay station.

DETAILED DESCRIPTION

FIG.1is a block diagram of an example wireless local area network (WLAN)10, according to an embodiment. Such a WLAN 10 may need to be able to update operating parameters across a range of different versions of Wi-Fi or IEEE 802.11. An access point (AP)14-1includes a host processor15coupled to a network interface16. The network interface16includes a medium access control (MAC) processing unit18and a physical layer (PHY) processing unit20. The PHY processing unit20includes a plurality of transceivers21, and the transceivers21are coupled to a plurality of antennas24. Although three transceivers21and three antennas24are illustrated inFIG.1, the AP14may include different numbers (e.g., 1, 2, 4, 5, etc.) of transceivers21and antennas24in other embodiments. The WLAN 10 may include multiple APs14-1,14-2,14-3as shown, but any number of APs14may be included in WLAN 10.

The WLAN 10 includes a plurality of client stations (STA)25. Although four client stations25are illustrated inFIG.1, the WLAN 10 may include different numbers (e.g., 1, 2, 3, 5, 6, etc.) of client stations25in various scenarios and embodiments. The WLAN 10 may also include AP multi-link device (MLD) where one AP MLD includes multiple affiliated APs and client STA multi-link devices (MLD) where one non-AP MLD includes multiple affiliated STAs. Two or more of the STAs of a non-AP MLD25are configured to receive corresponding data streams that are transmitted simultaneously by the AP14. Additionally, two or more of the STAs of a non-AP MLD25are configured to transmit corresponding data streams to one AP MLD14such that the AP MLD14simultaneously receives the data streams. Also, the client station MLD25are configured to receive data streams that are transmitted simultaneously by multiple APs of one AP MLD14. Likewise, the STAs of a non-AP MLD25may transmit data streams simultaneously to the multiple APs of an AP MLD14. MLD devices and operation will be described in more detail below.

A client station25-1includes a host processor26coupled to a network interface27. The network interface27includes a MAC processing unit28and a PHY processing unit29. The PHY processing unit29includes a plurality of transceivers30, and the transceivers30are coupled to a plurality of antennas34. Although three transceivers30and three antennas34are illustrated inFIG.1, the client station25-1may include different numbers (e.g., 1, 2, 4, 5, etc.) of transceivers30and antennas34in other embodiments.

In an embodiment, one or more of the client stations25-2,25-3, and25-4has a structure the same as or similar to the client station25-1. In these embodiments, the client stations25structured like the client station25-1have the same or a different number of transceivers and antennas. For example, the client station25-2has only two transceivers and two antennas (not shown), according to an embodiment.

In an embodiment, the APs14and the client stations25contend for communication medium using carrier sense multiple access with collision avoidance (CSMA/CA) protocol or another suitable medium access protocol. Further, in an embodiment, the APs14or a client station25dynamically selects a bandwidth for a transmission based on channels available for the transmission.

In an embodiment, the APs14are configured to simultaneously transmit different orthogonal frequency division multiplexing (OFDM) units to different client stations25by forming an orthogonal frequency division multiple access (OFDMA) resource unit (RU) that includes the different OFDM RUs modulated in respective sub-channel blocks of the OFDMA RU. In an embodiment, the AP14allocates different sub-channels to different client stations and forms the OFDMA RU that includes OFDM RUs directed to by modulating the different client stations in sub-channel blocks corresponding to the sub-channels assigned to the client stations.

In an embodiment, the APs14are configured to simultaneously transmit different OFDM units to different client stations25by transmitting the different OFDM RUs via different space time streams of a MU-MIMO communication channel to a single user (SU) or multiple users. In an embodiment, the APs14allocates different sub-channels and space time streams to different client stations and forms the OFDM RUs and modulates the different OFDM RUs to the space time streams corresponding to the sub-channels assigned to the client stations.

Various iterations of the 802.11 specification are referred to herein. IEEE 802.11ac is referred to as very high throughput (VHT). IEEE 802.11ax is referred to as high efficiency (HE). IEEE 802.11be is referred to as extreme high throughput (EHT). IEEE 802.11bn is referred to as ultra-high reliability (UHR). The terms VHT, HE, EHT, and UHR will be used in the descriptions found herein.

As described above a multi-link AP MLD has multiple links where each link has one AP affiliated with the AP MLD. This may be accomplished by having two different radios.

A multi-link STA MLD has one or multiple links where each link has one STA affiliated with the STA MLD. One way to implement the multi-link STA MLD is using two or more radios, where each radio is associated with a specific link. For example, an enhanced multi-link multi-radio (eMLMR) non-AP MLD may be used. The eMLMR non-AP MLD uses multiple full functional radios to monitor the medium in multiple links. Another way to implement the multi-link STA MLD is using a single radio in two different bands. Each band may be associated with a specific link. In this case only one link is available at a time. In yet another implementation, an enhanced single-radio (ESR) STA MLD may be used that operates in an enhanced multi-link single radio (eMLSR) mode. The ESR STA MLD uses two radios in different bands to implement the MLD. For example, one radio may be a lower cost radio with lesser capabilities and the other radio may be a fully functional radio supporting the latest protocols. The ESR STA MLD may dynamically switch its working link while it can only transmit or receive through one link at any time. The ESR STA MLD may monitor two links simultaneously, for example, detecting medium idle/busy status of each link, or receiving a PHY protocol data unit (PPDU) on each link. Each radio may have its own backoff time, and when the backoff counter for one of the radios becomes zero that radio and link may be used for transmission. For example, if an AP wants to use the fully functional radio, it may send a control frame that is long enough for the ESR STA MLD to switch from the lesser capable radio to the fully functional radio that may then transmit data to the AP.

In embodiments of a wireless communications system, a wireless device, e.g., an AP MLD of the WLAN may transmit data to at least one associated STA MLD. The AP MLD may be configured to operate with associated STA MLDs according to a communication protocol. For example, the communication protocol may be an Extremely High Throughput (EHT) communication protocol. Features of wireless communications and multi-link communication systems operating in accordance with the EHT communication protocol and/or next-generation communication protocols may be referred to herein as “non-legacy” features. In some embodiments of the wireless communications system described herein, different associated STAs within range of an AP operating according to the EHT communication protocol are configured to operate according to at least one other communication protocol, which defines operation in a BSS with the AP, but are generally affiliated with lower data throughput protocols. The lower data throughput communication protocols (e.g., HE, VHT, etc.) may be collectively referred to herein as “legacy” communication protocols.

An AP MLD in multi-link operation may remove its links through MLD reconfiguration. Multi-link (ML) reconfiguration broadly refers to a set of post-association procedures to make changes to links between APs and non-AP STAs affiliated with two MLDs including adding or removing links, and without disassociation. This may be accomplished using the reconfiguration multi-link element in a beacon frame. As a result, the AP MLD may have only one link after link removal. Also, a mobile AP MLD may only have one link because often these devices are power constrained, and the use of only a single link saves power. If an AP MLD with multiple links and a non-AP MLD with multiple links have one common link, they may do association through the common link. When links are removed, how the MLD operates with the single link is ambiguous under the current standards and should be clarified, e.g. whether the BSS Parameter Change Count and Critical Update Flag are mandatory requirement at the single-link non-AP MLD, whether the EMLSR mode is still used at non-AP MLD, and whether the radio switch padding delay is still needed for the first control frame addressed to an EMLSR non-AP MLD.

A relay STA (rSTA) may be used when an associated AP cannot reach a faraway STA with a high MCS or Nss. A rSTA may also be used when the AP cannot reach a faraway STA with the lowest MCS.FIG.2illustrates a leaf station (LSTA)205communicating with an AP215according to an embodiment. In this situation a rSTA210is used to forward communications from the LSTA205to the AP215and vice versa. As described above the rSTA210may be used when the LSTA205and the AP215are not able to directly communicate with one another effectively because of the distance between them. The rSTA210will allow for a higher data rate communication between the LSTA205and AP215. The AP215is typically able to operate with higher power and antenna gain than the210. It is noted that inFIG.2the use of just one rSTA210is illustrated, but any number of rSTAs210may be used to connect the LSTA205and the AP215.

FIG.3illustrates an upload (UL) frame transmission between the AP215and the LSTA205according to an embodiment. The AP215first sends a multi-user request to send (MU-RTS) triggered transmission opportunity sharing (TXS)302to the rSTA210. Next after a short interframe space (SIFS) period, the rSTA210sends a clear to send (CTS)304, and the LSTA205sends a CTS306in response to the MU-RTS TXS302. This indicates that the channel is clear. Then the AP215transmits a PPDU-1after a SIFS period. The rSTA210then sends a BA310after a SIFS period. It is noted that the sending of the BA310is optional. After a t_relay period of time, the rSTA210may then send a PPDU-2312to the LSTA205. PPDU-2312forwards the information of the PPDU-1308to the LSTA205. Then the LSTA205sends a multi-STA BS(M-B A)314back to the rSTA210acknowledging the receipt of the PPDU-2312. Finally, the rSTA210sends a M-BA316back to the AP215acknowledging the receipt of the PPDU-1308. It is noted that with the use of the rSTA210, a higher MCS may be used allowing for higher throughput between the LSTA205and the AP215versus a direct wireless link between them.

The DL frame transmission between the AP215and LSTA205are carried out similar to the exchange illustrated inFIG.3, but in reverse where PPDUs are transmitted by the AP215to the rSTA210, and PPDUs are transmitted by rSTA210to LSTA205.

To support communication between the AP215and the LSTA205via the rSTA210, it must be considered how to transmit beacons between the AP215and the LSTA205when a rSTA210may be used. The BA/Ack may be carried out end-to-end or hop-by-hop. With an end-to-end BA, the DL BA transmitted by AP215acknowledges the soliciting UL A-MPDU/BAR from LSTA205that is forwarded by the rSTA210. Likewise, the DL BA transmitted by AP215acknowledges the soliciting A-MPDU/BAR from the LSTA205that is forwarded by the rSTA210. With hop-by-hop DL BA, the DL BA transmitted by AP215acknowledges the soliciting UL A-MPDU/BAR from the rSTA210. Likewise, the DL BA transmitted by the rSTA210acknowledges the soliciting UL A-MPDU/BAR from LSTA205.

With hop-by-hop UL BA, the UL BA transmitted by the rSTA210acknowledges the soliciting DL A-MPDU/BAR from the AP215. Likewise, the UL BA transmitted by LSTA205acknowledges the soliciting DL A-MPDU/BAR from the rSTA210.

In 802.11, the beacon frame is one of the management frames. The beacon frame contains all the information about the network. Beacon frames are transmitted periodically, and they serve to announce the presence of a wireless LAN and to synchronize the members of the service set. Beacon frames are transmitted by the AP in a basic service set (BSS). In a BSS network beacon generation is distributed among the stations.

The beacon frames may include the following components: 802.11 MAC header, frame body, and FCS. Some of the fields in the body may include a timestamp, beacon interval, capability information, service set identifier (SSID), supported rates, Frequency-hopping (FH) Parameter Set, Direct-Sequence (DS) Parameter Set, Contention-Free (CF) Parameter Set, infrastructure BSS (IBSS) Parameter Set, and Traffic indication map (TIM).

The timestamp is used to synchronize the stations local clocks. After receiving the beacon frame all the stations change their local clocks to the timestamp time.

The beacon interval is the time interval between beacon transmissions. The time at which an AP must schedule a beacon transmission is known as target beacon transmission time (TBTT). Beacon interval expressed in time unit (TU). It is a configurable parameter in the AP215.

The capability information field spans to 16 bits and contains information about capability of the device/network. The type of network such as ad hoc or Infrastructure network is signaled in this field. Apart from this information, it announces the support for polling, as well as the encryption details.

The SSID provides the identifier for the BSS. The supported rates identifies the data rates supported by the device. The CF Parameter Set elements are included in beacon frames to keep all mobile stations apprised of contention-free operations. They are also included in Probe Response frames to allow stations to learn about contention-free options supported by a BSS. Various fields make up the CF Parameter Set information element.

IB SS Parameter Set element contains the set of parameters necessary to support an IB SS.

The TIM is a bitmap used to indicate to any sleeping listening stations that the AP has buffered data waiting for it. Because stations should listen to at least one beacon during the listen interval, the AP periodically sends this bitmap in its beacons as an information element. The bit mask is called the TIM and may include 2008 bits where each bit represents the association ID (AID) of a station.

During operation of a BSS, each AP schedules the beacon transmission at its TBTTs to synchronize stations that it communicates with as well as setting and updating parameters for the BSS. The beacon carries the AP's capabilities, BSS operating parameters etc. An associated STA with the AP synchronizes with the AP through the received beacons from the associated AP.

When using an AP215to facilitate communication between the AP215and the LSTA205, the question of how to carry out beaconing arises when a rSTA210is used.

A first approach specifies whether the rSTA210broadcasts beacons or not. An AP215announces whether the rSTAs210in the BSS forward the beacons received from the AP215, no transmission of the beacon received from the AP, or creates their beacons per the beacon received from the AP. This announcement is based on whether the beacons transmitted by the AP215by using a robust data rate and MCS can reach the associated LSTAs205.

When the AP's beacon cannot reach the associated LSTAs205, the AP215uses the rSTA210to get the beacons to the LSTA205by announcing that the associated RSTAs210forward the beacon or generate their own beacons. When the AP's beacons are not forwarded by RSTAs210, the AP's beacons may carry the beacon information of RSTAs210. Another option is that a RSTA210announces its information through a broadcast frame.

An associated LSTA205may decide whether it wants to transmit/receive frames to/from the AP215through a RSTA210depending upon the viable data rates and MCS that may be used. The AP215may decide whether to use the rSTA210to assist with beacon frames based upon the distances and locations of the LSTAs205and rSTAs210during setup of the BSS.

In a second approach, the rSTA210may copy any beacon it receives and forward the beacon information in a beacon frame that it transmits. For example, after a TBTT, a rSTA210forwards a beacon with a predefined inter-frame space (IFS), e.g. a SIFS, after the rSTA210receives the beacon with a traffic address (TA) equal to its associated AP215that is transmitted by its associated AP215or rSTA210.FIG.4illustrates the rSTA210forwarding a beacon402from the AP215according to an embodiment. The AP215transmits a beacon402that is received by the rSTA210. The rSTA210then transmits a beacon404with a SIFS time period between the end time of the receiving the beacon402and the start time to transmit the beacon402to the LSTA205. All the RSTAs use the same data rate (e.g., the same data rate as AP's beacon transmission) to forward the beacon. As mentioned before, there may be multiple rSTAs210between the AP215and LSTA205.

In a first option, the content of the forwarded beacon is the same as the received beacon. The LSTA205adjusts the timestamp per the number of hops to its associated AP215. A LSTA205that is N hops away from the AP215will use Received_Timestamp+N*(Predefined_IFS+Beacon_Tx_Time) as the Timestamp to account for the delay in transmitting the beacon404to the LSTA205, where the Received_Timestamp is the Timestamp in the received beacon, Predefined_IFS is a predefined IFS, the Beacon_Tx_Time is the received beacon transmit time.

In a second option, the content of the forwarded beacon is same as the received beacon with the following exception: the Timestamp in the forwarded beacon is equal to the sum of the Timestamp in the received beacon, predefined IFS, and the received beacon transmit time. That is the Timestamp from the rSTA210has been updated to accommodate for the delay in transmission so that the LSTA205does not need to make the adjustment.

Further, when a rSTA210forwards the AP's beacon404, a forwarding indication may be added to the beacon404, e.g., in the beacon frame body, in the frame header or in PHY header. Then the LSTA205knows that it is a forwarded beacon and can act accordingly. It is noted that in this scenario the LSTA205may also receive beacon402as well. Then the LSTA205can compare the information in beacon402and beacon404to know that they include the same information.

If the AP215requires the rSTA to forward its beacon, the AP215may schedule the transmission of a specific UHR PPDU to announce the following beacon transmission. The BSS Color or the other AP ID in UHR PPDU header may be used to identify that the AP215that transmits the UHR specific PPDU.FIG.5illustrates the UHR PPDU506that announces the beacon forwarding to the rSTA210according to an embodiment. The beacon502is then transmitted by the AP215after a SIFS time period to the rSTA210. The rSTA210then forwards the beacon502by transmitting beacon504to the LSTA205. The rSTA210detects the specific UHR PPDU from its associated AP215(per the AP's indication in UHR PPDU header) and the following beacon frame504will forward the received beacon frame502. The PPDU of the forwarding beacon has the same content as the received PPDU. The SERVICE field of the PPDU that carries the forwarded beacon, and the SERVICE field of the received PPDU that carries the received beacon are same. The forwarded beacon504and the received beacon502are the same. For example they will have the same data rate, MCS, and scramble initial value. When the rSTA210forwards the received beacon frame502, the rSTA210needs to guarantee the IFS accuracy to be same as the IFS accuracy when the CTS frame is transmitted when solicited by MU-RTS.

When the rSTA210copies the beacons from the AP215there are two options. In a first option, the beacon carries the AP's information only. Then the rSTA210announces its information through broadcast Management frame. In a second option, in the beacon frame, the AP announces the information of the rSTA210in its BSS in addition to the AP's information.

In a third approach the rSTA210beacon creation is carried out. After a TBTT, a rSTA210transmits a beacon through the backoff procedure.FIG.6illustrates a rSTA transmitting a beacon after a backoff procedure according to an embodiment. The AP215transmits a beacon602to the rSTA210. The rSTA210then creates and transmits beacon604after a backoff period of time. The TBTT may be the TBTT of its associated AP215or the TBTT of the rSTA210. Additional requirements of rSTA's beacon transmission could be that the rSTA210receives a beacon with a TA equal to its associated AP215and the rSTA210did not transmit the beacon after the TBTT. The Timestamp field carries the time synchronization function (TSF) time maintained by the rSTA210when the Timestamp field is transmitted through baseband/RF interface or other reference time agreed by the rSTA210and the LSTA205.

In a fourth approach, a LSTA205selects whether to use a rSTA210and is so which rSTA210of a group of available rSTAs to use. When a LSTA205receives an unsolicited PPDU from a rSTA210, the LSTA205may figure out the received signal strength indicator (RSSI) of the rSTA210. A LSTA205may transmit a PPDU to a rSTA210to solicit the responding PPDU from the rSTA210, and the LSTA205can figure out the RSSI of the rSTA210per the received PPDU from the RSTA Likewise, the LSTA205may determine the RSSI of the AP215based upon PPDUs received from the AP215. A LSTA205uses the RSSI of the received PPDU from a rSTA210and the RSSI of the PPDU from AP215to decide whether it does association and data frame exchanges through a rSTA210, and if so, which of multiple rSTAs210to use (if multiple rSTA210are present).

As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code—it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.

As used herein, the term “non-transitory machine-readable storage medium” will be understood to exclude a transitory propagation signal but to include all forms of volatile and non-volatile memory. When software is implemented on a processor, the combination of software and processor becomes a specific dedicated machine.

Because the data processing implementing the embodiments described herein is, for the most part, composed of electronic components and circuits known to those skilled in the art, circuit details will not be explained in any greater extent than that considered necessary as illustrated above, for the understanding and appreciation of the underlying concepts of the aspects described herein and in order not to obfuscate or distract from the teachings of the aspects described herein.

It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative hardware embodying the principles of the aspects.

While each of the embodiments are described above in terms of their structural arrangements, it should be appreciated that the aspects also cover the associated methods of using the embodiments described above.