Patent Description:
Wireless local area network (WLAN) technology allows devices to access the internet in the <NUM>, <NUM>, <NUM> or <NUM> frequency bands. WLANs are based on the Institute of Electrical and Electronic Engineers (IEEE) <NUM> standards. The IEEE <NUM> family of standards aim to increase speed and reliability and to extend the operating range of wireless networks.

Multi-link operation (MLO) is a key feature for next generation extremely high throughput (EHT) WI-FI systems, e.g., IEEE <NUM>. The WI-FI devices that support MLO are referred to as multi-link devices (MLDs). With MLO, it is possible for a non-access point (non-AP) MLD to discover, authenticate, associate, and set up multiple links with an AP MLD. Channel access and frame exchange is possible on each link that is set up between the AP MLD and non-AP MLD.

MLO has two variations. The first type is simultaneous transmit/receive (STR) where the STAs affiliated with an MLD can transmit and receive independent of each other. The second variation is non-simultaneous transmit/receive (NSTR) in which the links formed by the STAs affiliated with an MLD do not form an STR link pair. If a link pair constitutes an NSTR link pair, transmission on one link can cause interference to the other link due to signal leakiness which the device's radio transceiver is unable to withstand. Consequently, two STAs forming an NSTR link pair cannot simultaneously transmit and receive frames. Since the STR mode of operation requires two or more radios with sufficient isolation, it is expected that AP MLDs will have STR capabilities while non-AP MLDs are more likely not to be capable of STR, and thus use NSTR.

An MLD can be configured as a Mobile AP. For instance, when a battery powered mobile device is configured as a Mobile AP, it executes the functionalities of an AP. It can utilize links with a WI-FI router as the backhaul and one or more links connected to another MLD to provide connectivity to that other MLD. The role of an AP is performed on the latter links. When configured as a Mobile AP, an MLD may be required to support high throughput applications (e.g., AR, VR, etc.).

Document <CIT> discloses a multi-link device witih several APs, each of them establishing a link with a non-AP STA of a Non-AP device.

Documents <NPL> and "<NPL> disclose the configurations for establishment of multi-link connections.

Document <CIT> discloses a Non-AP MLD and its establishment of different links with an AP MLD.

Embodiments of the present disclosure provide methods and apparatuses for facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in a wireless local area network.

In one embodiment, an MLD is provided, according to claim <NUM>.

In one embodiment, a method performed by an MLD is provided, according to claim <NUM>.

The following documents and standards descriptions are referred to in the present disclosure:.

<FIG>, discussed below, and the one embodiment used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure.

Embodiments of the present disclosure recognize that devices, such as non-AP MLDs, associated with a Mobile AP MLD for traffic flows may need an internet connection to run various services such as gaming applications, video applications, etc. Consequently, an architecture and procedure for setting up backhaul links to provide internet access to the devices associated with the Mobile AP MLD is necessary.

Accordingly, embodiments of the present disclosure provide apparatuses and methods that facilitate setting up backhaul links for a Mobile AP MLD. Further, the disclosure also provides methods and signaling procedures for their discovery as well as exchanging relevant information.

<FIG> illustrates an example wireless network <NUM> according to one embodiment of the present disclosure. The embodiment of the wireless network <NUM> shown in <FIG> is for illustration only.

The wireless network <NUM> includes APs <NUM> and <NUM>. The APs <NUM> and <NUM> communicate with at least one network <NUM>, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network. The AP <NUM> provides wireless access to the network <NUM> for a plurality of STAs <NUM>-<NUM> within a coverage area <NUM> of the AP <NUM>. The APs <NUM>-<NUM> may communicate with each other and with the STAs <NUM>-<NUM> using Wi-Fi or other WLAN communication techniques.

Depending on the network type, other well-known terms may be used instead of "access point" or "AP," such as "router" or "gateway. " For the sake of convenience, the term "AP" is used in this disclosure to refer to network infrastructure components that provide wireless access to remote terminals. In WLAN, given that the AP also contends for the wireless channel, the AP may also be referred to as a STA (e.g., an AP STA). Also, depending on the network type, other well-known terms may be used instead of "station" or "STA," such as "mobile station," "subscriber station," "remote terminal," "user equipment," "wireless terminal," or "user device. " For the sake of convenience, the terms "station" and "STA" are used in this disclosure to refer to remote wireless equipment that wirelessly accesses an AP or contends for a wireless channel in a WLAN, whether the STA is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer, AP, media player, stationary sensor, television, etc.). This type of STA may also be referred to as a non-AP STA.

In one embodiment of this disclosure, each of the APs <NUM> and <NUM> and each of the STAs <NUM>-<NUM> may be an MLD. In such embodiments, APs <NUM> and <NUM> may be AP MLDs, and STAs <NUM>-<NUM> may be non-AP MLDs. Each MLD is affiliated with more than one STA. For convenience of explanation, an AP MLD is described herein as affiliated with more than one AP (e.g., more than one AP STA), and a non-AP MLD is described herein as affiliated with more than one STA (e.g., more than one non-AP STA).

It should be clearly understood that the coverage areas associated with APs, such as the coverage areas <NUM> and <NUM>, may have other shapes, including irregular shapes, depending upon the configuration of the APs and variations in the radio environment associated with natural and man-made obstructions.

As described in more detail below, one or more of the APs may include circuitry and/or programming for facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs. Although <FIG> illustrates one example of a wireless network <NUM>, various changes may be made to <FIG>. For example, the wireless network <NUM> could include any number of APs and any number of STAs in any suitable arrangement. Also, the AP <NUM> could communicate directly with any number of STAs and provide those STAs with wireless broadband access to the network <NUM>. Similarly, each AP <NUM>-<NUM> could communicate directly with the network <NUM> and provide STAs with direct wireless broadband access to the network <NUM>. Further, the APs <NUM> and/or <NUM> could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

<FIG> illustrates an example AP <NUM> according to one embodiment of the present disclosure. The embodiment of the AP <NUM> illustrated in <FIG> is for illustration only, and the AP <NUM> of <FIG> could have the same or similar configuration. In the embodiments discussed herein below, the AP <NUM> is an AP MLD. However, APs come in a wide variety of configurations, and <FIG> does not limit the scope of this disclosure to any particular implementation of an AP.

The AP MLD <NUM> is affiliated with multiple APs 202a-202n (which may be referred to, for example, as AP1-APn). Each of the affiliated APs 202a-202n includes multiple antennas 204a-204n, multiple RF transceivers 209a-209n, transmit (TX) processing circuitry <NUM>, and receive (RX) processing circuitry <NUM>. The AP MLD <NUM> also includes a controller/processor <NUM>, a memory <NUM>, and a backhaul or network interface <NUM>.

The illustrated components of each affiliated AP 202a-202n may represent a physical (PHY) layer and a lower media access control (LMAC) layer in the open systems interconnection (OSI) networking model. In such embodiments, the illustrated components of the AP MLD <NUM> represent a single upper MAC (UMAC) layer and other higher layers in the OSI model, which are shared by all of the affiliated APs 202a-202n.

For each affiliated AP 202a-202n, the RF transceivers 209a-209n receive, from the antennas 204a-204n, incoming RF signals, such as signals transmitted by STAs in the network <NUM>. In some embodiments, each affiliated AP 202a-202n operates at a different bandwidth, e.g., <NUM>, <NUM>, or <NUM>, and accordingly the incoming RF signals received by each affiliated AP may be at a different frequency of RF. In other embodiments, each affiliated AP 202a-202n can operate at various different bandwidths, and the RF transceivers 209a-209n include transceivers capable of operating at those different bandwidths. The RF transceivers 209a-209n down-convert the incoming RF signals to generate IF or baseband signals. The RX processing circuitry <NUM> transmits the processed baseband signals to the controller/ processor <NUM> for further processing.

For each affiliated AP 202a-202n, the TX processing circuitry <NUM> receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor <NUM>. The RF transceivers 209a-209n receive the outgoing processed baseband or IF signals from the TX processing circuitry <NUM> and up-convert the baseband or IF signals to RF signals that are transmitted via the antennas 204a-204n. In embodiments wherein each affiliated AP 202a-202n operates at a different bandwidth, e.g., <NUM>, <NUM>, or <NUM>, the outgoing RF signals transmitted by each affiliated AP may be at a different frequency of RF.

The controller/processor <NUM> can include one or more processors or other processing devices that control the overall operation of the AP MLD <NUM>. For example, the controller/processor <NUM> could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 209a-209n, the RX processing circuitry <NUM>, and the TX processing circuitry <NUM> in accordance with well-known principles. The controller/processor <NUM> could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor <NUM> could support beam forming or directional routing operations in which outgoing signals from multiple antennas 204a-204n are weighted differently to effectively steer the outgoing signals in a desired direction. The controller/processor <NUM> could also support OFDMA operations in which outgoing signals are assigned to different subsets of subcarriers for different recipients (e.g., different STAs <NUM>-<NUM>). Any of a wide variety of other functions could be supported in the AP MLD <NUM> by the controller/processor <NUM> including facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs. In some embodiments, the controller/processor <NUM> includes at least one microprocessor or microcontroller. The controller/ processor <NUM> can move data into or out of the memory <NUM> as required by an executing process.

The backhaul or network interface <NUM> allows the AP MLD <NUM> to communicate with other devices or systems over a backhaul connection or over a network. For example, the interface <NUM> could allow the AP MLD <NUM> to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The memory <NUM> is coupled to the controller/ processor <NUM>.

As described in more detail below, the AP MLD <NUM> may include circuitry and/or programming for facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs. Although <FIG> illustrates one example of AP MLD <NUM>, various changes may be made to <FIG>. For example, the AP MLD <NUM> could include any number of each component shown in <FIG>. As a particular example, an AP MLD <NUM> could include a number of interfaces <NUM>, and the controller/processor <NUM> could support routing functions to route data between different network addresses. As another particular example, while each affiliated AP 202a-202n is shown as including a single instance of TX processing circuitry <NUM> and a single instance of RX processing circuitry <NUM>, the AP MLD <NUM> could include multiple instances of each (such as one per RF transceiver) in one or more of the affiliated APs 202a-202n. Alternatively, only one antenna and RF transceiver path may be included in one or more of the affiliated APs 202a-202n, such as in legacy APs.

<FIG> illustrates an example STA <NUM> according to one embodiment of this disclosure. The embodiment of the STA <NUM> illustrated in <FIG> is for illustration only, and the STAs <NUM>-<NUM> of <FIG> could have the same or similar configuration. In the embodiments discussed herein below, the STA <NUM> is a non-AP MLD. However, STAs come in a wide variety of configurations, and <FIG> does not limit the scope of this disclosure to any particular implementation of a STA.

The non-AP MLD <NUM> is affiliated with multiple STAs 203a-203n (which may be referred to, for example, as STA1-STAn). Each of the affiliated STAs 203a-203n includes antenna(s) <NUM>, a radio frequency (RF) transceiver <NUM>, TX processing circuitry <NUM>, and receive (RX) processing circuitry <NUM>. The non-AP MLD <NUM> also includes a microphone <NUM>, a speaker <NUM>, a controller/processor <NUM>, an input/output (I/O) interface (IF) <NUM>, a touchscreen <NUM>, a display <NUM>, and a memory <NUM>.

The illustrated components of each affiliated STA 203a-203n may represent a PHY layer and an LMAC layer in the OSI networking model. In such embodiments, the illustrated components of the non-AP MLD <NUM> represent a single UMAC layer and other higher layers in the OSI model, which are shared by all of the affiliated STAs 203a-203n.

For each affiliated STA 203a-203n, the RF transceiver <NUM> receives, from the antenna(s) <NUM>, an incoming RF signal transmitted by an AP of the network <NUM>. In some embodiments, each affiliated STA 203a-203n operates at a different bandwidth, e.g., <NUM>, <NUM>, or <NUM>, and accordingly the incoming RF signals received by each affiliated STA may be at a different frequency of RF. In other embodiments, each affiliated STA 203a-203n can operate at various different bandwidths, and may include multiple RF transceivers that are capable of operating at those different bandwidths. The RX processing circuitry <NUM> transmits the processed baseband signal to the speaker <NUM> (such as for voice data) or to the controller/processor <NUM> for further processing (such as for web browsing data).

For each affiliated STA 203a-203n, the TX processing circuitry <NUM> receives analog or digital voice data from the microphone <NUM> or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the controller/processor <NUM>. The RF transceiver <NUM> receives the outgoing processed baseband or IF signal from the TX processing circuitry <NUM> and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) <NUM>. In embodiments wherein each affiliated STA 203a-203n operates at a different bandwidth, e.g., <NUM>, <NUM>, or <NUM>, the outgoing RF signals transmitted by each affiliated STA may be at a different frequency of RF.

The controller/processor <NUM> can include one or more processors and execute the basic OS program <NUM> stored in the memory <NUM> in order to control the overall operation of the non-AP MLD <NUM>. In one such operation, the main controller/ processor <NUM> controls the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver <NUM>, the RX processing circuitry <NUM>, and the TX processing circuitry <NUM> in accordance with well-known principles. The main controller/processor <NUM> can also include processing circuitry configured to facilitate the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs. In some embodiments, the controller/ processor <NUM> includes at least one microprocessor or microcontroller.

The controller/processor <NUM> is also capable of executing other processes and programs resident in the memory <NUM>, such as operations for facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs. In some embodiments, the controller/processor <NUM> is configured to execute a plurality of applications <NUM>, such as applications for facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs. The controller/ processor <NUM> can operate the plurality of applications <NUM> based on the OS program <NUM> or in response to a signal received from an AP. The main controller/processor <NUM> is also coupled to the I/O interface <NUM>, which provides non-AP MLD <NUM> with the ability to connect to other devices such as laptop computers and handheld computers. The I/O interface <NUM> is the communication path between these accessories and the main controller <NUM>.

The controller/processor <NUM> is also coupled to the touchscreen <NUM> and the display <NUM>. The operator of the non-AP MLD <NUM> can use the touchscreen <NUM> to enter data into the non-AP MLD <NUM>. The memory <NUM> is coupled to the controller/ processor <NUM>.

Although <FIG> illustrates one example of non-AP MLD <NUM>, various changes may be made to <FIG>. In particular examples, one or more of the affiliated STAs 203a-203n may include any number of antenna(s) <NUM> for MIMO communication with an AP <NUM>. In another example, the non-AP MLD <NUM> may not include voice communication or the controller/processor <NUM> could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while <FIG> illustrates the non-AP MLD <NUM> configured as a mobile telephone or smartphone, non-AP MLDs can be configured to operate as other types of mobile or stationary devices.

In one embodiment of the present disclosure, the non-AP MLD <NUM> of <FIG> may be an MLD in which some of the STAs 203a-203n are configured as non-AP STAs and some are configured as AP STAs that form a Mobile AP MLD within the MLD <NUM>. The AP STAs of the Mobile AP MLD are configured to associate with other non-AP MLDs, such as non-AP MLD <NUM>. Meanwhile, the non-AP STAs of the MLD <NUM> may form backhaul links with an AP MLD, such as AP MLD <NUM>. The backhaul links may be used as a backhaul for traffic flowing through the AP STAs of the Mobile AP MLD from the associated non-AP MLDs (such as non-AP MLD <NUM>). The backhaul links may be set up on-demand as needed or requested.

<FIG> illustrates an example network scenario including an MLD that comprises both non-AP STAs and AP STAs that form a Mobile AP MLD according to one embodiment of the present disclosure. For ease of explanation, the AP MLD <NUM> (also referred to as AP MLD1) is illustrated with two affiliated AP STAs, the MLD <NUM> (also referred to as Device A) is illustrated with two affiliated non-AP STAs, and two affiliated AP STAs, and the non-AP MLD <NUM> is illustrated with two affiliated non-AP STAs, but it is understood that this scenario could be applied with suitable MLDs having any number of affiliated AP STAs or non-AP STAs.

As shown in <FIG>, STA1 and STA2 located on Device A are configured as non-AP STAs whereas AP1 and AP2 located on Device A are configured as AP STAs (or simply APs) that form a Mobile AP MLD <NUM> (which may be referred to simply as a Mobile AP). The non-AP STAs (STA <NUM> and STA <NUM>) and the AP STAs (AP1 and AP2) are affiliated with the same MLD (Device A). Further, STA1 and STA2 form link1 and link2 after association with AP3 and AP4, respectively, which are affiliated with AP MLD1. Further, AP1 and AP2 of the Mobile AP MLD form primary link and non-primary link with STA3 and STA4, respectively, which are affiliated with non-AP MLD1.

According to one embodiment, the above architecture can be used to lower the latency for traffic flowing from AP MLD1 to non-AP MLD1 via the Mobile AP. According to one embodiment, the above architecture can be used to create on-demand backhaul links (in addition to existing backhaul links) to boost the net speed of the backhaul for the Mobile AP.

According to some embodiments, such an on-demand backhaul link can be requested by the non-AP STAs affiliated with the non-AP MLD1 to the AP STAs affiliated with the Mobile AP. That is, the non-AP STAs affiliated with the non-AP MLD1 can send a request to the AP STAs affiliated with the Mobile AP. Upon receiving such a request, the AP STAs affiliated with the Mobile AP MLD can then create an on-demand backhaul link to boost the net speed of the backhaul.

According to one embodiment, in order to create an awareness that device A has setup its Mobile AP MLD and backhaul according to the above architecture, device A can provide an indication via frames transmitted by the Mobile AP MLD or frames transmitted by the STAs that constitute the backhaul links. The Mobile AP MLD can indicate its capability to form backhaul links to the non-AP MLD1 associated with it in one or more frames transmitted by the Mobile AP MLD to the non-AP MLD1.

According to this embodiment, the Mobile AP MLD can provide information related to the STAs that are capable of setting up backhaul links to the associated non-AP MLD1 in one or more frames transmitted by the Mobile AP MLD to the non-AP MLD1. The Mobile AP MLD can indicate the availability of, and information related to, the STAs that are capable of setting up backhaul links via a Reduced Neighbor Report element. Further, according to this embodiment, an AP affiliated with the Mobile AP MLD can include a reduced neighbor report element containing such information in beacon and probe response frames that it transmits, and such beacon and probe response frames can be transmitted on the primary link of the Mobile AP MLD.

When the non-AP MLD associated with the Mobile AP MLD receives such information, it can interpret such information as information corresponding to STAs that constitute the backhaul after determining that the transmitter sending such information is a Mobile AP MLD. Further, according to this embodiment, the Mobile AP MLD can indicate that the information it transmits to its associated non-AP MLD in a reduced neighbor report element corresponds to a STA constituting the backhaul link by providing an indication in one of the fields of the reduced neighbor element. According to one such embodiment, this indication may be made using one or more bits from the MLD Parameters sub-field of the reduced neighbor report element.

<FIG> illustrates an example MLD Parameters sub-field format including a backhaul STA indicator according to one embodiment of the present disclosure. The Backhaul STA Indicator bit can be set to <NUM> when the information in the Reduced Neighbor Report element corresponds to a STA that constitutes the backhaul link and is set to <NUM> otherwise.

When using the Reduced Neighbor Report element to indicate the presence of, or information related to, STAs that constitute the backhaul links, the fields of the Reduced Neighbor Report element that are not relevant for characterization of a STA but are relevant for characterization of an AP (e.g., BSSID, Short SSID, BSS parameters, etc.) can be used for providing information about the AP with which a STA that constitutes a backhaul link is associated. According to one embodiment, such fields can be left empty or can be omitted if that option is available in the Reduced Neighbor Report element.

According to embodiments, the Mobile AP MLD can indicate information of the STAs that constitute the backhaul in a Basic multi-link element. Further, according to this embodiment, the Mobile AP MLD can include the complete profile of a STA in the Per-STA Profile sub-element in the Basic Multi-link element. When such information is included in the Per-STA Profile sub-element, one or more bits of a STA control field can be used to indicate that the information corresponds to a STA that constitutes the backhaul link.

<FIG> illustrates an example STA control field format including a backhaul STA indicator according to embodiments of the present disclosure. In this example, bit B11 (a Backhaul STA Indicator bit) is set to <NUM> to indicate that corresponding STA information carried in a Per-STA Profile sub-element belongs to a STA that constitutes a backhaul link, and is set to <NUM> otherwise.

According to one embodiment, the STAs that constitute the backhaul can provide, to the APs that they are associated with, an indication about the presence of, or information related to, the APs that constitute the Mobile AP MLD. According to one such embodiment, the STAs that constitute the backhaul can indicate the presence of the APs that constitute the Mobile AP MLD via the Reduced Neighbor Report element. When an AP receives a Reduced Neighbor Report element from a non-AP STA, the information can be interpreted as discussed below after determining that the transmitter sending such information is a non-AP STA.

According to one such embodiment, the AP that receives a Reduced Neighbor Report element can be informed about the APs that constitute the Mobile AP MLD by the non-AP STA (e.g., STA1 or STA2) by using one or more bits of the MLD Parameters sub-field.

<FIG> illustrates an example MLD Parameters sub-field format including a bit that indicates that included information corresponds to an AP of a Mobile AP MLD according to one embodiment of the present disclosure. In this example, the B21 bit (a Mobile AP MLD Indicator bit) is set to <NUM> when the information in the Reduced Neighbor Report element corresponds to an AP of the Mobile AP MLD, and is otherwise set to <NUM>.

When an AP of an AP MLD receives a Reduced Neighbor Report element from an associated non-AP STA (e.g., STA1 or STA2), it can interpret the information in the Reduced Neighbor Report as belonging an AP of a Mobile AP MLD (e.g., AP1 or AP2 of Mobile AP MLD <NUM>) being reported by a STA located on the same device (e.g., Device A).

According to one embodiment, the STAs that constitute the backhaul can indicate information of the APs of the Mobile AP MLD in the Basic multi-link element. Further, according to this embodiment, a STA can include the complete profile of an AP in the Per-STA Profile sub-element in the Basic Multi-link element. According to one embodiment, when such information is included in the Per-STA Profile sub-element, one or more bits of the STA control field can be used to indicate that the information corresponds to an AP of the Mobile AP MLD.

<FIG> illustrates an example STA control field format including a Mobile AP MLD indicator according to one embodiment of the present disclosure. In this example, bit B11 (a Mobile AP MLD indicator bit) is used to indicate that corresponding information included in the Per-STA Profile sub-element belongs to an AP of the Mobile AP MLD when B11 is set to <NUM>. When the information does not correspond to an AP of the Mobile AP MLD, the bit can be set to <NUM>.

According to one embodiment, the STA that sends information about an AP of the Mobile AP MLD in the Reduced Neighbor Report element can further indicate whether the AP is an AP that forms the primary link of the Mobile AP MLD by using one or more bits of the Reduced Neighbor Report element. According to one embodiment, this indication can be provided via the MLD Parameters sub-field.

<FIG> illustrates an example MLD Parameters sub-field format including a primary link AP indication according to one embodiment of the present disclosure. In this example, bit B22 (a Primary Link AP Indicator bit) is set to <NUM> when the information in the Reduced Neighbor Report element corresponds to the primary link AP of the Mobile AP MLD, and is otherwise set to <NUM>.

According to one embodiment, this information can also be indicated in the Basic multi-link element. When such information is included in the Per-STA Profile sub-element, one or more bits of the STA control field can be used to indicate that the information corresponds to an AP that forms the primary link of the Mobile AP MLD.

<FIG> illustrates an example STA control field format including a primary link AP indication according to one embodiment of the present disclosure. In this example, the bit B12 (a Primary Link AP Indicator bit) is set to <NUM> to indicate that information carried in a Per-STA Profile sub-element belongs to an AP that constitutes the primary link of the Mobile AP MLD, and is set to <NUM> otherwise.

According to one embodiment, the links used for backhaul formation can be shared to carry traffic that does not originate from the APs of the Mobile AP. According to this embodiment, the STAs that constitute the backhaul links can also use the backhaul links to carry their own downlink and uplink traffic.

According to one such embodiment, the Mobile AP MLD can indicate that the STAs that constitute the backhaul can have their own downlink and uplink traffic - i.e., they constitute a shared backhaul link - via the Reduced Neighbor Report element. According to one embodiment, this indication can be provided by the Mobile AP MLD via the MLD Parameters sub-field.

<FIG> illustrates an example MLD Parameters sub-field including a shared backhaul indication according to one embodiment of the present disclosure. In this example, bit B22 (a Shared Backhaul Indicator bit) is set to <NUM> to indicate a shared backhaul link, and is set to <NUM> otherwise.

According to one embodiment, this information can be indicated in the Basic multi-link element. When such information is included in the Per-STA Profile sub-element, one or more bits of the STA control field can be used to indicate that the information corresponds to a STA that creates a shared backhaul link.

<FIG> illustrates an example STA control field format including a shared backhaul indication according to one embodiment of the present disclosure. In this example, bit B12 (a Shared Backhaul Indicator bit) is set to <NUM> to indicate a shared backhaul link, and is set to <NUM> otherwise.

According to one embodiment, a STA that constitutes the backhaul link can provide an indication that the QoS expectations of a traffic flow that it provides to its associated AP affiliated with an AP MLD corresponds to the traffic being generated by the Mobile AP MLD by using one or more fields of a QoS characteristic element. Such an indication can enable the AP MLD with which the STA that constitutes the backhaul link is associated to perform appropriate resource allocation for traffic of the Mobile AP MLD and for the traffic of the STA itself.

According to one such embodiment, the STA can provide such an indication via the Control Info field of the QoS characteristic element.

<FIG> illustrates an example Control Info field format of a QoS characteristic element including an indication of that QoS expectations of a traffic flow correspond to traffic being generated by a Mobile AP MLD according to one embodiment of the present disclosure. In this example, the Direction sub-field of the Control field can be used to provide this indication. When the B0 and B1 bits of the Direction sub-field are both set to <NUM>, the QoS expectations indicated in the QoS characteristic element can be considered as belonging to the traffic corresponding to the Mobile AP.

According to one embodiment, the above architecture can be used for improving coordination for setup of backhaul links and access links - i.e., UL/DL links - of the Mobile AP MLD such that they do not interfere with each other. For example, backhaul link STAs and APs of the Mobile AP MLD may negotiate to reconfigure backhaul links as needed.

<FIG> and <FIG> illustrate an example process from the point of view, respectively, of a backhaul link STA and an AP of the Mobile AP MLD to negotiate reconfiguration of a backhaul link according to one embodiment of the present disclosure. Upon determining that reconfiguration of a backhaul link is necessary (step <NUM>), a backhaul link STA can send a negotiation frame (step <NUM>) to request a reconfiguration from the AP. Upon receiving the negotiation frame from the STA (step <NUM>), the AP can either determine if the reconfiguration proposed by the STA is feasible or not or can determine a suitable reconfiguration (step <NUM>). The AP can then provide confirmation to the STA about link reconfiguration (steps <NUM> and <NUM>). Following this, both AP and STA can adopt the new configuration at the indicated time (steps <NUM> and <NUM>).

According to this embodiment, a STA that constitutes the backhaul link can indicate the desired backhaul link channel configuration to its associated AP MLD as shown in <FIG> and <FIG>. Such an indication can be provided by the STA to its associated AP by transmitting a frame containing the channel number that it desires for the backhaul link.

<FIG> illustrates an example negotiation frame transmitted by a backhaul STA to an AP with indication of a desired backhaul link configuration according to one embodiment of the present disclosure. In this example, the frame transmitted by the STA to the associated AP contains a per-link configuration field which provides information about the configuration desired for each link.

<FIG> illustrates an example per-link configuration field format of a negotiation frame according to one embodiment of the present disclosure. The sub-fields of the per-link configuration field can contain the information shown in Table <NUM>.

In one embodiment, upon receiving such a negotiation frame, the AP can use the indicated information and change the configuration to suit the Mobile AP MLD's needs without any explicit notification to the STA.

In one embodiment, upon receiving such a negotiation frame, the AP can transmit a negotiation response frame (with the same format as the negotiation frame). In the response frame, the AP can include per-link configuration elements which contain the link ID, the desired channel number that the AP intends to set, and the channel config change time that the AP intends to set. In this embodiment, the AP may choose to determine another configuration (if the one indicated by the STA is not suitable for it). The information indicated in the response frame would correspond to the final configuration that the AP intends to set.

In one embodiment, the STA can transmit a negotiation frame containing only link IDs of the backhaul links that need reconfiguration. <FIG> illustrates an example negotiation frame transmitted by a backhaul STA to an AP including link IDs of backhaul links that need reconfiguration according to one embodiment of the present disclosure. The negotiation frame of this example can contain the information shown in Table <NUM>.

<FIG> illustrates an example format of the Link ID List of Table <NUM> and <FIG> according to one embodiment of the present disclosure.

Furthermore, the STA can also provide information related to the APs of the Mobile AP MLD in the per-STA profile sub-element (e.g., leveraging the indication signaling of the STA Control field in the embodiments of <FIG> or <FIG>).

Based on the above embodiments, upon receiving a negotiation frame from the STA (e.g., as illustrated in <FIG>), the AP that the backhaul link STA is associated with can have knowledge of the backhaul links that need reconfiguration. The AP would also have knowledge of the configuration of the APs of the Mobile AP. The APs that the backhaul link STAs are associated with can then use the information in the per-STA profile and determine a configuration for the backhaul links such that they does not interfere with the access links of the Mobile AP MLD.

<FIG> illustrates an example process for configuration of the access links of the Mobile AP to avoid violating NSTR conditions according to one embodiment of the present disclosure. As illustrated in this example, when Mobile AP Mode (also referred to as "Soft AP Mode") is initiated (step <NUM>), the MLD (e.g., Device A) can check if access links (or "Soft AP links") of the Mobile AP form an NSTR link pair with a backhaul link (step <NUM>). The MLD can maintain a set of channel configurations with which a sufficient level of isolation can be achieved such that its STAs can operate in STR mode. If NSTR link pairs are detected via the check, and if the MLD has such a set of channel configurations (step <NUM>), then MLD can configure the Mobile AP links to avoid NSTR conflicts with the backhaul (step <NUM>).

In one such embodiment, the MLD can divide the supported frequency bands (or channels) into groups that do not result in any NSTR conflicts and assign bands from one of such groups to the Mobile AP links. In one embodiment, the use of adjacent bands for Mobile AP links and backhaul links can be avoided while configuring the STAs. For example, a Mobile AP link may be configured to operate in the <NUM> band whereas the backhaul link is configured to operate in the <NUM> band.

The configuration of the Mobile AP links to avoid NSTR conflicts can be achieved via procedures used in the group formation process. In one embodiment, the Mobile AP links can be configured using the Mobile AP (or Soft AP) group owner (GO) negotiation procedure.

<FIG> illustrates an example Mobile AP (or Soft AP) group owner negotiation process for configuration of the access links of the Mobile AP to avoid violating NSTR conditions according to one embodiment of the present disclosure. In this example, the Mobile AP (or Soft AP) can transmit a modified GO Negotiation Request frame to its associated STA (e.g., STA2).

In one embodiment, the GO Negotiation Request frame can carry the operating channel attribute (configured by the Mobile AP to avoid NSTR conflicts with the backhaul) and an updated channel list attribute (including the channels that avoid NSTR conflicts with the backhaul).

In one embodiment, the GO Negotiation Request frame can contain a bit indicating an NSTR related configuration issue to indicate to the STA2 to accept the proposed configuration without modification or choose a configuration from the options made available in the channel list attribute. STA2 can either accept the proposed configuration or indicate a new configuration in the GO Negotiation response frame.

In yet one embodiment, the GO Negotiation Request frame can contain an NSTR bitmap to indicate the set of links that form NSTR link pairs with the backhaul. The associated STA2 can choose the configuration such that NSTR links are not formed with the backhaul, and indicate the choice via the GO Negotiation Response frame. In one embodiment, the GO Negotiation Request frame can contain an STR bitmap instead of the NSTR bitmap.

In one embodiment, when the Mobile AP links have not been set up, the Mobile AP can use procedures of the Mobile AP autonomous mode. The Mobile AP can use channels that do not cause any NSTR conflicts with the backhaul links and transmit beacons only on the selected channels. Thereby, the clients can discover the Mobile AP on the selected channels and continue further communication on the same channels.

<FIG> illustrates an example wait time procedure for avoiding violation of NSTR conditions according to one embodiment of the present disclosure. In this example, when the Mobile AP is ready to transmit on its access links, it can check the backoff counter value of a STA used for a backhaul link. For example, when a backoff counter of an AP of the Mobile AP reaches zero, the AP can check if the backoff counter of a STA forming the backhaul and having NSTR conflicts with the access link has also reached zero. If the STA backoff counter has reached zero, the AP of the Mobile AP and the STA forming the backhaul can proceed as per the NSTR channel access procedure and initiate transmission.

However, if the backoff counter of the backhaul link STA has not reached zero, the AP of the Mobile AP can reserve the channel for an amount of time that is equal to the time to transmit its own data (including time for any MAC layer overhead, interframe spacings and acknowledgement) plus the remaining backoff counter value of the backhaul link STA. Following this, the AP of the Mobile AP can set a wait time (Twait) equal to the remainder of the backoff counter of the backhaul link STA. When the wait time is completed, the AP of the Mobile AP can again check if the backhaul link STA is ready to transmit.

At this point, if the backhaul link STA is ready to transmit, the AP of the Mobile AP and the backhaul link STA can initiate transmission. However, it may happen that the backhaul link STA is not ready to transmit (e.g., the backhaul link STA has initiated a deferral procedure due to a transmission from a STA affiliated with a different MLD on its own link). When this happens, in one embodiment, the AP of the Mobile AP can start the transmission without the backhaul link STA. In one embodiment, the AP of the Mobile AP can compute the remainder of the deferral duration for the backhaul link STA and determine if the transmission can tolerate an additional delay of that amount. If it can, the AP of the Mobile AP can set another wait time equal to the computed amount and again check the status of the backhaul link STA following the wait.

<FIG> illustrate an example process facilitating the use of STAs of an MLD to set up and operate backhaul links to serve a Mobile AP within the same MLD in WLANs according to one embodiment of the present disclosure. The process of <FIG> is discussed as being performed by an MLD <NUM>, but it is understood that a corresponding AP MLD <NUM> and a corresponding non-AP MLD <NUM> perform corresponding processes. Additionally, for convenience, the process of <FIG> is discussed as being performed by a WI-FI MLD comprising a plurality of STAs that each comprise a transceiver, wherein some of the plurality of STAs are configured as APs forming a Mobile AP MLD, and some of the plurality of STAs are configured as backhaul STAs. However, it is understood that any suitable wireless communication device could perform these processes.

Referring to <FIG>, the process begins with the MLD instructing at least one AP forming the Mobile AP MLD to set up an access link with a corresponding STA of a non-AP MLD (step <NUM>). The access link may include a primary link and a non-primary link.

Next, the MLD transmits, from the at least one AP to the corresponding STA of the non-AP MLD, a capability indication that indicates availability of the at least one backhaul STA to form the backhaul link (step <NUM>). The capability indication may be a reduced neighbor report element or a basic multi-link element.

After step <NUM> is performed, the MLD will then receive, at the at least one AP from the corresponding STA of the non-AP MLD, a request to set up the backhaul link (step <NUM>).

At step <NUM>, the MLD instructs at least one backhaul STA to set up a backhaul link with a corresponding AP of an AP MLD to carry traffic of the non-AP MLD that flows through the Mobile AP MLD over the access link. Step <NUM> is performed in response to the request received at step <NUM> (e.g., to create an on-demand backhaul link),.

The MLD may then, in some embodiments, transmit, from the at least one backhaul STA to the corresponding AP of the AP MLD, an indication of information related to the APs of the Mobile AP MLD for which the backhaul link carries traffic (step <NUM>). This indication may be a reduced neighbor report element or a basic multi-link element.

Referring now to <FIG>, the MLD may determine that reconfiguration of the backhaul link is necessary to avoid interference between the backhaul link and the access link (step <NUM>). In some cases, the MLD may also determine a desired channel configuration for the reconfiguration of the backhaul link (step <NUM>).

The MLD then transmits, from the at least one backhaul STA to the corresponding AP of the AP MLD, a request for the reconfiguration of the backhaul link (step <NUM>). If step <NUM> was performed, then the reconfiguration request includes the desired channel configuration. In other cases, the reconfiguration request instead includes a link identifier of the backhaul link that needs reconfiguration, and may also include configuration information of the APs of the Mobile AP MLD.

Next, the MLD receives, at the at least one backhaul STA from the corresponding AP of the AP MLD, a response to the request that includes information on a new configuration for the backhaul link and an indication of a time to adopt the new configuration (step <NUM>). The information on the new configuration for the backhaul link may be the information on the desired channel configuration, if transmitted at step <NUM>, or may be information on a different channel configuration determined by the AP of the AP MLD.

The MLD then instructs the at least one backhaul STA to adopt the new configuration at the indicated time (step <NUM>).

Referring now to <FIG>, the MLD may receive QoS expectations of a traffic flow corresponding to the traffic that flows through the Mobile AP MLD (step <NUM>).

The MLD then transmits, from the at least one backhaul STA to the corresponding AP of the AP MLD, a QoS characteristic element that includes the QoS expectations of the traffic flow and an indication that the traffic flow corresponds to the Mobile AP MLD (step <NUM>).

The above flowcharts illustrate an example method that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the method illustrated in the flowcharts. For example, while shown as a series of steps, various steps could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.

Claim 1:
A multi-link device, MLD, comprising:
access points, APs,(<NUM>) forming a Mobile AP MLD (<NUM>), each of the APs comprising a transceiver (<NUM>);
backhaul stations, STAs,(<NUM>) each of the backhaul STAs comprising a transceiver (<NUM>); and
a processor (<NUM>) operably coupled to the APs and the backhaul STAs, the processor configured to:
generate a capability indication that indicates availability of the backhaul STAs to form a backhaul link,
wherein the transceiver (<NUM>) of the at least one AP is configured to:
transmit, to a corresponding STA of a non-AP MLD, the capability indication; and
receive, from the corresponding STA of the non-AP MLD, a request to set up the backhaul link, and
the processor is configured to: instruct the at least one backhaul STA to set up the backhaul link in response to the received request;
instruct at least one of the APs to set up an access link with the corresponding STA of the non-AP MLD; and
instruct at least one of the backhaul STAs to set up the backhaul link with a corresponding AP of an AP MLD to carry traffic of the non-AP MLD that flows through the Mobile AP MLD over the access link.