Dynamic methods and procedures for secondary channel access in a wifi system

Abstract

Systems and methods are provided for enabling use of remaining bandwidth when a primary portion is occupied, busy, or otherwise unavailable. In particular, the present disclosure relates to implementations of secondary channel access via one or more secondary channels when a primary channel is busy or occupied. In an example, when the primary channel is busy, a wireless device can switch to monitoring one of its secondary sub-channels for physical and virtual carrier sensing. A first device can define and advertise one or more anchor channels that can be used as sub-channels on which other devices can perform channel access using physical and / or virtual carrier sensing. The anchor channels can be temporarily used as the primary channel when the primary channel is busy. In some implementations, the device can continue to monitor the primary channel and can switch back to the primary channel when the primary channel becomes available again.

Description

Cross-references to related applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 620,813, filed January 13, 2024, the contents of which are incorporated herein by reference. Background Technology

[0002] In some implementations of wireless local area network (WLAN) systems with multiple channel widths, a portion (or sometimes most) of the available bandwidth of the system (e.g., the basic service set (BSS)) may be wasted due to media access by a single station (STA) or overlapping BSSs operating only on a portion of the available bandwidth. For example, a portion of the bandwidth used for the first BSS may be busy or may experience interference from overlapping BSSs. This portion may be referred to as the primary channel, and some or all of the remaining bandwidth may be referred to as secondary channels. Summary of the Invention

[0003] Various aspects of this disclosure may relate to implementations of systems and methods that enable the use of remaining bandwidth when the primary channel is occupied, busy, or otherwise unavailable by a transmitter, receiver, or both. In particular, aspects may relate to implementations for secondary channel access via one or more secondary sub-channels when the primary sub-channel is busy or occupied. In some implementations, when the primary channel is busy, a wireless device (including an access point (AP), a non-AP station (STA), or other wireless transmit / receive unit (WTRU)) may switch to monitoring one of its secondary sub-channels for physical and virtual carrier sensing.

[0004] In one aspect, a first device (such as an AP) can define and advertise one or more anchor channels, which can be used as sub-channels for non-primary channel access (NPCA) by the AP and STA using physical and / or virtual carrier sensing. When the primary channel is busy, the anchor channel can be used as a temporary primary channel. In some implementations, the device can begin transmitting on the anchor channel when physical and / or virtual carrier sensing determines that the radio media is idle or free from interference. In some implementations, the device can continue monitoring the primary channel and can switch back to the primary channel when it becomes available again.

[0005] In one example, a device / method for use in a wireless local area network (WLAN) station (STA) (e.g., an AP STA or a non-AP STA) may include: determining that the first AP will switch from the primary channel to an anchor channel associated with the first AP based on the primary channel being unavailable. Before a timer associated with the first AP expires, the STA receives a control frame from a second AP indicating that the anchor channel associated with the first AP is idle. In response to receiving the control frame, the STA transmits a transmission via the anchor channel for accessing the anchor channel. In various aspects, the STA may be the first AP, i.e., an AP STA, or a non-AP STA associated with the first AP. In various aspects, the first AP and the second AP are associated with a multi-AP group (MAP). In some aspects, the anchor channel associated with the first AP conforms to the primary channel associated with the second AP. In various aspects, the control frame may be a short control frame, including one of a request to transmit (RTS), allow to transmit (CTS), a buffer status report polling (BSRP) frame, a buffer status report response (BSRR) frame, and a trigger frame, the short control frame having a duration field for setting the network allocation vector (NAV), the duration field being set to zero. This allows a STA that receives a control frame on the anchor channel to immediately respond to non-master channel access on the anchor channel. In one example, the timer associated with the first AP is a synchronization delay timer. In another example, the first and second APs use the same bandwidth.

[0006] According to other aspects of this disclosure, an example STA / method used in the STA may include receiving an indication from the AP associated with the STA of an anchor channel for non-primary channel access when the AP's primary channel is unavailable. The STA determines that the AP's primary channel is unavailable and monitors the indicated anchor channels. The STA receives a control frame from the AP on one of the monitored anchor channels, indicating that the corresponding anchor channel is idle and the duration for which the AP will remain on the anchor channel. In response to receiving the control frame, the STA transmits a transmission for anchor channel access via the anchor channel. According to some aspects, the STA receives a Transmission Opportunity (TXOP) from the AP on the anchor channel for the STA to transmit or receive on the anchor channel. In one example, the STA then sends an indication to the AP on the anchor channel during the TXOP that the STA will remain on the anchor channel for a longer period after the TXOP than indicated by the AP. In a variant example, before sending the indication that the STA will remain on the anchor channel after the TXOP, the STA receives an indication from the AP on the anchor channel that the STA should remain on the anchor channel after the TXOP.

[0007] In various implementations, the control frame is one of a Request to Send (RTS), Allow to Send (CTS), Buffer Status Report Polling (BSRP) frame, and trigger frame. In some aspects, the control frame may have a duration field used by the STA to set its Network Allocation Vector (NAV), which is set to zero to allow the STA to immediately contend for anchor channel access. In various examples, the anchor channel is a secondary channel for the bandwidth of the AP used for channel bonding. In various examples, the anchor channel conforms to or falls within the bandwidth of the primary channel of the second AP in a multi-AP group (MAP) with APs. Additional aspects, features, and advantages will become apparent from the detailed embodiments described below. Attached Figure Description

[0008] A more detailed understanding can be obtained from the following description given with reference to the accompanying drawings, in which the same reference numerals in the figures denote the same elements, and wherein: Figure 1A This is a system diagram illustrating an example communication system that can implement one or more of the disclosed embodiments; Figure 1B This illustrates that, according to an embodiment, it is possible to Figure 1A The system diagram shown is of an example wireless transmit / receive unit (WTRU) used in the communication system. Figure 1C This illustrates that, according to an embodiment, it is possible to Figure 1A The system diagram shows an example radio access network (RAN) and an example core network (CN) used in the communication system shown. Figure 1D This illustrates that, according to an embodiment, it is possible to Figure 1A The system diagram shown illustrates another example RAN and another example CN used within the communication system. Figure 2 It is a signal flow diagram of secondary channel access using the target wake-up time according to some implementation methods; Figure 3A This is a table showing example target wake-up time elements according to some implementation methods; Figure 3B This is a table showing example target wake-up time control fields based on some implementation methods; Figure 3C This is a table showing a single parameter field for the target wake-up time based on some implementation methods; Figure 4 This is a signal diagram illustrating an embodiment of MAP-assisted synchronization recovery according to some implementation methods; Figure 5 This is a signal diagram illustrating an embodiment of switching between the main channel and the anchor channel according to some implementation methods; and Figure 6 This is a signal diagram illustrating another embodiment of switching between the main channel and the anchor channel according to some implementation methods. Detailed Implementation

[0009] Figure 1A This diagram illustrates an example communication system 100 that can implement one or more of the disclosed embodiments. The communication system 100 can be a multiple access system that provides content such as voice, data, video, messaging, and broadcasting to multiple wireless users. The communication system 100 enables multiple wireless users to access such content through shared system resources including wireless broadband. For example, the communication system 100 can employ one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Zero-Tail Unique Word Discrete Fourier Transform Extended OFDM (ZT-UW-DFT-S-OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), etc.

[0010] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112. However, it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d can be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRUs 102a, 102b, 102c, and 102d (any of which may be referred to as a station (STA)) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0011] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be base transceiver stations (BTS), node Bs, eNodeBs (eNBs), master node Bs, master eNodeBs, next-generation node Bs such as gNode Bs (gNBs), new radio (NR) node Bs, site controllers, access points (APs), wireless routers, etc. Although base stations 114a and 114b are each depicted as a single element, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0012] Base station 114a may be part of RAN 104, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a specific geographic area that may be relatively fixed or may change over time. A cell may also be divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one for each sector of the cell. In embodiments, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0013] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0014] More specifically, as described above, the communication system 100 can be a multiple access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base station 114a in RAN 104 and WTRUs 102a, 102b, and 102c can implement radio technologies, such as using Wideband CDMA (WCDMA) to establish Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) for air interface 116. WCDMA can include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​Uplink (UL) Packet Access (HSUPA).

[0015] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies, such as using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro) to establish Evolved UMTS Terrestrial Radio Access (E-UTRA) for air interface 116.

[0016] In the embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies, such as using NR to establish NR radio access for air interface 116.

[0017] In the embodiments, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can, for instance, use the dual connectivity (DC) principle to jointly implement LTE radio access and NR radio access. Therefore, the air interface used by WTRUs 102a, 102b, and 102c can be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0018] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.11 (i.e., WiFi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), GSMEDGE (GERAN), etc.

[0019] Figure 1A Base station 114b can be, for example, a wireless router, master node B, master eNode B, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for use by drones), roads, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-a, LTE-a Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can be directly connected to Internet 110. Therefore, base station 114b does not need to access Internet 110 via CN 106.

[0020] RAN 104 can communicate with CN 106, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although... Figure 1AAs not shown, but will be understood, RAN 104 and / or CN 106 can communicate directly or indirectly with other RANs that use the same RAT as or a different RAT than RAN 104. For example, in addition to connecting to RAN 104, which may be utilizing NR radio technology, CN 106 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0021] CN 106 can also serve as a gateway for WTRUs 102a, 102b, 102c, and 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 or a different RAT.

[0022] Some or all of the WTRUs 102a, 102b, 102c, and 102d in communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, Figure 1A The WTRU 102c shown can be configured to communicate with a base station 114a that can use cellular-based radio technology and with a base station 114b that can use IEEE 802 radio technology.

[0023] Figure 1B This is a system diagram illustrating example WTRU 102. (See diagram below.) Figure 1B As shown, WTRU 102 may include a processor 118, a transceiver 120, a transmitting / receiving element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, etc. It will be understood that, while remaining consistent with the embodiments, WTRU 102 may include any sub-combination of the foregoing elements.

[0024] Processor 118 can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. Processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 can be coupled to transceiver 120, which can be coupled to transmitting / receiving element 122. Although Figure 1B While the processor 118 and transceiver 120 are depicted as separate components, it will be understood that the processor 118 and transceiver 120 can be integrated together in an electronic package or chip.

[0025] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In another embodiment, transmitting / receiving element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF signals and optical signals. It will be understood that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0026] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. More specifically, WTRU 102 may employ MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via air interface 116.

[0027] Transceiver 120 can be configured to modulate signals transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As described above, WTRU 102 can have multi-mode capability. Therefore, transceiver 120 can include multiple transceivers for enabling WTRU 102 to communicate via various RATs (e.g., such as NR and IEEE 802.11).

[0028] The processor 118 of WTRU 102 can be coupled to and receive user input data from: a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit). The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Additionally, the processor 118 can access information and store data from any suitable type of memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a subscriber identity module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 can access information and store data from memory not actually located on WTRU 102, such as on a server or home computer (not shown).

[0029] The processor 118 may receive power from the power supply 134 and may be configured to distribute power to other components in the WTRU 102 and / or control power to those other components. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0030] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that, while remaining consistent with the embodiments, the WTRU 102 may acquire location information using any suitable location determination method.

[0031] The processor 118 can also be connected to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or videos), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral devices 138 may include one or more sensors. These sensors may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, humidity sensors, etc.

[0032] WTRU 102 may include a full-duplex radio, wherein some or all of the transmission and reception of signals (e.g., associated with a specific subframe of both UL (e.g., for transmission) and DL (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In embodiments, WTRU 102 may include a half-duplex radio, wherein some or all of the transmission and reception of signals (e.g., associated with a specific subframe of both UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0033] Figure 1C This is a system diagram illustrating RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 can employ E-UTRA radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 104 can also communicate with CN 106.

[0034] RAN 104 may include eNode-Bs 160a, 160b, and 160c, but it will be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, for example, eNode-B 160a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a.

[0035] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0036] Figure 1C The CN 106 shown may 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 CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0037] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, activating / deactivating bearers, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0038] The SGW 164 can connect to each of the eNode Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can typically route and forward user data packets to or from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during eNode-B handover, triggering paging when DL data is available to WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c.

[0039] SGW 164 can be connected to PGW 166, which can provide WTRU 102a, 102b, 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0040] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRUs 102a, 102b, and 102c with access to circuit-switched networks (such as PSTN 108) to facilitate communication between WTRUs 102a, 102b, and 102c and traditional terrestrial line communication equipment. For example, CN 106 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and PSTN 108, or can communicate with it. Additionally, CN 106 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0041] Despite WTRU in Figures 1A to 1D While described as a wireless terminal, it is envisioned that, in some representative embodiments, such a terminal may (e.g., temporarily or permanently) use a wired communication interface with a communication network.

[0042] In a representative embodiment, the other network 112 may be a WLAN.

[0043] A WLAN in Infrastructure Basic Services Set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may access a distribution system (DS) or another type of wired / wireless network that loads traffic into and / or loads traffic out of the BSS, or have an interface to it. Traffic originating outside the BSS destined for a STA can be delivered to the AP via it. Traffic from a STA destined for a destination outside the BSS can be sent to the AP for delivery to the appropriate destination. Traffic between STAs within the BSS can be sent via the AP, for example, where a source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as point-to-point traffic. Point-to-point traffic can be sent between a source STA and a destination STA using a direct link setup (DLS) (e.g., directly between them). In some representative embodiments, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as a "self-organizing" communication mode in this document.

[0044] When operating in 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of fixed width (e.g., a bandwidth of 20 MHz) or dynamically configured. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, Carrier Sense Multiple Access - Collision Avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. For CSMA / CA, each STA (e.g., every STA), including the AP, can sense the primary channel. If a particular STA senses / detects that the primary channel is busy and / or determines that the primary channel is busy, that particular STA can back off. In a given BSS, at any given time, only one STA (e.g., only one station) can transmit.

[0045] High-throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels.

[0046] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-consecutive 80 MHz channels, which can be referred to as an 80+80 configuration. In the 80+80 configuration, after channel coding, data can be passed through a fragment parser, which splits the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed on each stream separately. The streams can be mapped onto the two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations of the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0047] 802.11af and 802.11ah support operating modes below 1 GHz. The channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV Blank (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument-type control / machine-type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only) certain and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0048] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be designated as the primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by the STAs operating in the BSS that support the minimum bandwidth operating mode. In the 802.11ah example, for STAs that support (e.g., only support) the 1 MHz mode (e.g., MTC type devices), the primary channel can be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier Sense and / or Network Assignment Vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy, for example, due to STAs (which only support the 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even if most available frequency bands remain idle.

[0049] In the United States, the available frequency band for 802.11ah is 902 MHz to 928 MHz. In South Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0050] Figure 1D This is a system diagram illustrating RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 may employ NR radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 104 may also communicate with CN 106.

[0051] RAN 104 may include gNBs 180a, 180b, and 180c, but it will be understood that RAN 104 may include any number of gNBs while remaining consistent with the embodiments. gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Thus, for example, gNB 180a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In embodiments, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be located on unlicensed spectrum, while the remaining component carriers may be located on licensed spectrum. In embodiments, gNBs 180a, 180b, and 180c can implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0052] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable parameter sets. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing can be varied for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes of various or scalable lengths or transmission time intervals (TTIs) (e.g., containing different numbers of OFDM symbols and / or absolute times of varying durations).

[0053] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as mobile anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c while also communicating / connecting with another RAN (such as eNode-Bs 160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-Bs 160a, 160b, and 160c can act as mobile anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput to serve WTRUs 102a, 102b, and 102c.

[0054] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, interoperability between DC, NR, and E-UTRA, routing of user plane data to User Plane Functions (UPF) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0055] Figure 1DThe CN 106 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although the foregoing elements are depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0056] AMF 182a and 182b can connect to one or more of the gNBs 180a, 180b, and 180c in RAN 104 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different Protocol Data Unit (PDU) sessions with different requirements), selecting specific SMF 183a and 183b, managing registration areas, terminating Non-Access Stratum (NAS) signaling, mobility management, etc. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the service types being used by WTRU 102a, 102b, and 102c. For example, different network slices can be created for different use cases, such as services that rely on Ultra Reliable Low Latency (URLLC) access, services that rely on Enhanced Massive Mobile Broadband (eMBB) access, and services for MTC access. AMF 182a and 182b can provide control plane functions for handover between RAN 104 and other RANs (not shown) that employ other radio technologies (such as LTE, LTE-A, LTE-A Pro) and / or non-3GPP access technologies (such as WiFi).

[0057] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 106 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 106 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure traffic routing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing DL data notifications. PDU session types can be IP-based, non-IP-based, or Ethernet-based.

[0058] UPF 184a and 184b can connect to one or more of the gNBs 180a, 180b, and 180c in RAN 104 via the N3 interface. These gNBs can provide WTRU 102a, 102b, and 102c with access to packet-switched networks (such as the Internet 110) to facilitate communication between WTRU 102a, 102b, and 102c and IP-enabled devices. UPF 184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering DL packets, and providing mobility anchoring.

[0059] CN 106 can facilitate communication with other networks. For example, CN 106 may include or be able to communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and PSTN 108. Additionally, CN 106 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c can be connected to DNs 185a and 185b via UPFs 184a and 184b through their N3 interfaces and the N6 interface between UPFs 184a and 184b and local DNs 185a and 185b.

[0060] Given Figures 1A to 1D and Figures 1A to 1D The corresponding descriptions can be performed by one or more emulation devices (not shown) that perform one or more of the functions described herein with respect to: WTRU 102a to 102d, base stations 114a to 114b, eNode-B 160a to 160c, MME 162, SGW 164, PGW 166, gNB 180a to 180c, AMF 182a to 182b, UPF 184a to 184b, SMF 183a to 183b, DN 185a to 185b, and / or any other devices described herein. An emulation device can be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0061] Simulation devices can be designed to perform one or more tests on other devices in laboratory and / or carrier network environments. For example, one or more simulation devices may perform one or more functions when fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices may perform one or more functions when temporarily implemented / deployed as part of a wired and / or wireless communication network. Simulation devices may be directly coupled to another device for testing purposes and / or use over-the-air wireless communication to perform tests.

[0062] One or more simulation devices may perform one or more functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, a simulation device may be used to test scenarios in a laboratory and / or an undeployed (e.g., tested) wired and / or wireless communication network to enable testing of one or more components. One or more simulation devices may be test equipment. Simulation devices may transmit and / or receive data using direct RF connections and / or wireless communication via an RF circuit system (e.g., which may include one or more antennas).

[0063] As described in IEEE Standard 802.11™-2020: Wireless Local Area Network (WLAN) Media Access Control (MAC) and Physical Layer (PHY) Specification, which is incorporated herein by reference: WLANs in Infrastructure Basic Services Set (BSS) mode have an access point (AP) for the BSS (i.e., AP STA) and one or more stations (STAs) associated with the AP (i.e., non-AP STAs). APs typically have access to a distribution system (DS) or another type of wired / wireless network that loads and unloads traffic into and out of the BSS, or have an interface to it. Traffic originating outside the BSS destined for a STA arrives via the AP and is delivered to the STA. Traffic from a STA destined for a destination outside the BSS is sent to the AP for delivery to the appropriate destination. Traffic between STAs within the BSS can also be sent via the AP, where the source STA sends traffic to the AP, and the AP delivers the traffic to the destination STA. This traffic between STAs within the BSS is effectively point-to-point traffic. This point-to-point traffic can also be sent directly between a source STA and a destination STA with a direct link setup (DLS) using 802.11e DLS or 802.11z tunneled DLS (TDLS). WLANs using the Standalone BSS (IBSS) mode do not have APs and / or STAs communicating directly with each other. This communication mode is called a "self-organizing" communication mode.

[0064] In infrastructure mode (e.g., BSS infrastructure mode), the AP can transmit beacons on a fixed channel (typically the primary channel). In the example, this channel might be 20 MHz wide and referred to as the working channel of the BSS. In some implementations, this channel is also used by the STA to establish a connection with the AP. In some implementations, the basic channel access mechanism in an 802.11 system is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). In this operating mode, each STA, including the AP, will sense whether the primary channel is occupied or idle. If the channel is detected to be busy, the STA backs off. Therefore, in a given BSS, only one station can transmit at any given time.

[0065] In 802.11n, High Throughput (HT) STAs can also communicate using a 40 MHz wide channel. This is achieved by combining a primary 20 MHz channel with an adjacent 20 MHz channel to form a continuous 40 MHz wide channel.

[0066] Described in the IEEE P802.11ax™ / D8.0: Wireless LAN Media Access Control (MAC) and Physical Layer (PHY) specification and incorporated herein by reference, the Very High Throughput (VHT) STA can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and 160 MHz. 40 MHz and 80 MHz channels can be formed by combining consecutive 20 MHz channels, similar to the 802.11n configuration described above. Combining lower bandwidth channels to create a larger bandwidth channel is sometimes referred to as channel bonding. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-consecutive 80 MHz channels, which can also be referred to as an 80+80 configuration. For the 80+80 configuration, in some implementations, the data at the transmitter, after channel coding, is passed through a fragment parser that splits the data into two streams. Inverse Fast Fourier Transform (IFFT) and time-domain processing are performed on each stream. The stream is then mapped onto both channels, and data is transmitted. At the receiver, this mechanism is reversed, and the combined data is sent to the MAC layer.

[0067] 802.11af and 802.11ah support operating modes below 1 GHz. For these specifications, the channel operating bandwidth and carrier are reduced compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV Blank (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. A possible use case for 802.11ah is supporting meter-type control (MTC) devices within a macro coverage area. MTC devices can have limited capabilities, including supporting only limited bandwidth, but can also include requirements for very long battery life.

[0068] WLAN systems supporting multiple channels and channel widths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel designated as the primary channel. The primary channel may, but does not necessarily, have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. Therefore, the bandwidth of the primary channel is limited by the STAs operating in the BSS that support the minimum bandwidth operating mode. In the 802.11ah example, if there are STAs that only support the 1 MHz mode (e.g., MTC-type devices), the primary channel can be 1 MHz wide, even if the AP and other STAs in the BSS can support 2 MHz, 4 MHz, 8 MHz, 16 MHz, or other channel bandwidth operating modes. In many implementations, carrier sense and NAV settings depend on the state of the primary channel; that is, if the primary channel is busy, for example, due to STAs only supporting the 1 MHz operating mode transmitting to the AP, the entire available band is considered busy even if most of the available band remains idle and available.

[0069] In the United States, the available frequency bands for 802.11ah are 902 MHz to 928 MHz. In South Korea, the available bands are 917.5 MHz to 923.5 MHz; and in Japan, the available bands are 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz, depending on the country code. Other frequency bands and channel widths may be used depending on the application and implementation.

[0070] As previously mentioned, in some implementations of wireless local area network (WLAN) systems with multiple channel widths, a portion (or sometimes most) of the available bandwidth of the system (e.g., the Basic Service Set (BSS)) may be wasted due to media access by a single station (STA) or overlapping BSSs operating only on a portion of the available bandwidth. For example, a portion of the bandwidth used for the first BSS may be busy or may experience interference from overlapping BSSs. This portion can be referred to as the primary channel, and some or all of the remaining bandwidth can be referred to as secondary channels. In WLANs, a "primary channel" generally refers to the main frequency band used for wireless communication, while a "secondary channel" is typically paired with the primary channel to create one or more additional frequency bands with wider bandwidth, generally used to increase data throughput by "binding" the channels together. Essentially, the primary channel handles control functions and is always active, while the secondary channel is used for data transmission when needed and requires compatibility between devices to operate effectively.

[0071] Several approaches to Secondary Channel Access (SCA) have been explored, but various drawbacks exist. For example, in Sub-Channel Selective Transmission (SST) implementations (such as those used with 802.11ax), the STA can transmit and receive on the secondary channel. High-Efficiency (HE) SST non-AP STAs and HE SST APs can establish SST operation by negotiating an enabled TWT using a separate Target Wake-Up Time (TWT) protocol.

[0072] refer to Figure 2 Example method 200 for standalone TWT operation is shown, in which STA1 sends a TWT request 205 and receives a TWT response 210 from AP to set a TWT service period 215 to trigger activation, during which STA1 should be awake and ready to receive and / or send. Reference Figures 3A to 3B An example of a TWT element 300 with corresponding control field 320 and TWT parameter information field 340 used in this process is shown.

[0073] refer to Figure 3B An example of TWT control field 320 is shown, where negotiation type subfield 322 may include broadcast type subfield (not shown), which may indicate whether TWT element 300 is used for broadcast TWT or standalone TWT. If the broadcast type subfield of negotiation type subfield 322 is 0, then the TWT element is used for standalone TWT, and then only one set of standalone TWT parameter information fields 340 is included in TWT element 300.

[0074] exist Figure 3CThe diagram illustrates an example of a separate TWT parameter information field 340, which includes a TWT channel subfield 342. The TWT channel subfield 342 indicates the subchannels that the STA may need to monitor during the negotiated TWT SP. SST operation allows non-AP STAs to operate on either a secondary 20 MHz or secondary 80 MHz subchannel in the negotiated TWT SP. Non-AP STAs should be available at the TWT start time and should not use Distributed Coordination Function (DCF) or Enhanced Distributed Channel Access Function (EDCAF) to access the media on the subchannels. Instead, channel access for non-AP STAs during SST operation is trigger-based, meaning the AP grants uplink resources for the non-AP STA to perform uplink transmissions. Non-AP STAs may include a channel handover timing element in their (re)association request frames sent to the AP to indicate the time required for the STA to handover between different subchannels.

[0075] The embodiments disclosed herein may relate to implementations of systems and methods for enabling the use of remaining bandwidth when the primary channel is occupied, busy, or otherwise unavailable by a transmitter, receiver, or both. In particular, embodiments for secondary channel access (SCA) via one or more secondary sub-channels are disclosed when the primary sub-channel is busy or occupied. In some implementations, when the primary channel is busy, wireless devices (including access points (APs), non-AP stations (STAs), or other wireless transmit / receive units (WTRUs)) may switch to monitoring one of their secondary (sub)channels for physical and virtual carrier sensing.

[0076] In one example embodiment, a first device (such as an AP) may define and advertise one or more (sub)channels (referred to herein as anchor channels), which can be used by the AP and STAs to perform channel access using physical and / or virtual carrier sensing. In various examples, the anchor channel may be used as a temporary primary channel when the primary channel is busy. This may be referred to as non-primary channel access (NPCA). In some examples, the anchor channel (which may be interchangeably referred to herein as an NPCA primary channel) may use a 20 MHz resolution or a 40 MHz resolution. Anchor channels / NPCA primary channels may differ from the primary channel generally described in the preceding paragraphs. For example, a primary channel may refer to a 20 MHz channel in which CCA / NAV operations are typically performed. Alternatively or concurrently, a primary channel may refer to a channel in which one or more STAs are configured to perform CCA / NAV operations by default. In contrast, the terms anchor channel and / or NPCA primary channel may refer to a 20 MHz channel in which one or more STAs are configured to perform CCA / NAV when the primary channel is occupied. Anchored channels and / or NPCA primary channels can be considered as secondary channels.

[0077] In some implementations, the device can begin transmitting on the anchor channel when physical and / or virtual carrier sensing determines that the wireless medium is idle and / or free from interference. In other implementations, the device can continue monitoring the primary channel and can switch back to the primary channel when it becomes available again.

[0078] In embodiments where multi-link operation (MLO) can be used, secondary channel access (SCA) can be supported per link. This means that the first STA associated with a STA MLD can support SCA, while another STA associated with the same STA MLD may not support SCA. Alternatively, in another implementation, SCA can be supported per device. In such an implementation, if the STA MLD supports SCA operation, then all STAs associated with the STA MLD can support SCA. If the STA MLD does not support SCA operation, then all STAs associated with the STA MLD may not support SCA.

[0079] In some example embodiments, the anchor channel may have a resolution of 20 MHz or 40 MHz. In some implementations, the secondary channel may have a resolution of 20 MHz, 40 MHz, 60 MHz, 80 MHz, or 160 MHz. Access to the secondary channel can be achieved through access to the anchor channel. Therefore, in some implementations, anchor channel access may refer to secondary channel access (SCA). In one example, the AP may operate on a 320 MHz channel and its primary 20 MHz sub-channel may be within its primary 160 MHz sub-channel. In one example, one or more 20 MHz sub-channels from the secondary 160 MHz channel may be selected as anchor channels. In one example, a 20 MHz sub-channel from the secondary 80 MHz sub-channel, a 20 MHz sub-channel from the third 80 MHz channel, and / or a 20 MHz sub-channel from the fourth 80 MHz sub-channel may be selected and used as anchor channels.

[0080] The following embodiments primarily relate to AP STAs and non-AP STAs. However, implementations of these systems and methods can be equally applied to AP MLDs and / or non-AP STA MLDs, as well as APs associated with AP MLDs and non-AP STAs associated with non-AP STA MLDs, or any combination of the foregoing.

[0081] Existing Network Allocation Vector (NAV) setting methods are typically unrelated to bandwidth. For example, a STA can receive a PPDU. The STA can read the SIG field or MAC header to obtain the Transmission Opportunity (TXOP) Duration field or Duration field to set the NAV. Therefore, the NAV setting is unrelated to any specific channel or sub-channel. However, for primary / anchor channel handover, the STA may need to know whether the NAV setting is for the primary channel, the anchor channel, or both. Therefore, the STA / AP may need sub-channel-based NAV setting capabilities. If the Physical Layer Protocol Data Unit (PPDU) triggering the primary / anchor channel handover is an intra-BSS PPDU, the STA can check the Bandwidth (BW) field and Punch Channel Indicator in the SIG field to determine the sub-channel that the NAV may be associated with. If the PPDU triggering the primary / anchor channel handover is an inter-BSS downlink (DL) PPDU, the STA can check the Basic Service Set Identifier (BSSID) field or Transmitter Address (TA) in the MAC header field to determine which AP sent the PPDU. If the STA previously received a beacon frame from an AP (an inter-BSS AP acting as the transmitter or receiver of the PPDU), the STA can determine the BSS's operating channel and primary channel. Using this information, or a portion thereof, along with the BW field in the PPDU's SIG field, the STA can determine on which sub-channels the PPDU can be transmitted. If the PPDU is an inter-BSS uplink (UL) PPDU, the STA can check the BSSID field or receiver address (RA) in the MAC header field to identify the AP acting as the receiver of the PPDU. Alternatively or additionally, the STA can detect whether it has received any energy on the anchor channel when receiving the PPDU. In this way, the STA can determine whether a NAV has also been set for the anchor channel. The following discussion also applies to implementations where a NAV is set on the primary channel, the anchor channel, or both the primary and anchor channels. For example, when a NAV is set on the primary channel, the NAV can be set only on the primary channel and not on the anchor or secondary channels.

[0082] In some example implementations, after a device (AP or STA) switches to an anchor channel, it can use one or more of the following processes to access the anchor channel. In some modes, both the AP STA and a non-AP STA can be allowed to use CSMA / CA to access the secondary channel. In another mode, the AP can perform anchor channel access, and the non-AP STA may need to wait for the AP to send a trigger for uplink transmission. If the AP has an additional radio or RF chain, it can use the radio or RF chain to monitor the anchor channel or the next anchor channel the AP can switch to. The AP can determine under what conditions it can use the radio / RF chain to monitor the anchor channel. For example, in some implementations, if the AP notices that a neighboring BSS is operating on the same operating channel or the same primary channel, and that activity from the neighboring BSS is frequent, the AP can use an additional radio / RF chain to monitor the anchor channel. The AP may have already updated the NAV settings on the anchor channel, and the AP may need to adhere to the NAV on that anchor channel when it switches to the anchor channel. If the AP does not have updated NAV settings on the anchor channel, it may need to monitor the anchor channel and follow one or more of these rules to perform channel access: (i) The AP may start a MediumSyncDelay timer (or a timer of other names) immediately after switching to the anchor channel, and if the AP has not yet detected or has not detected any transmissions from another WiFi device on the anchor channel, the AP may attempt to contend for or gain priority for transmission over the media on the anchor channel when the MediumSyncDelay timer reaches 0; and (ii) If the AP receives a PPDU with valid NAV information on the anchor channel, the AP may attempt to contend for or acquire the priority for transmission via the medium after the NAV duration on the anchor channel.

[0083] In some implementations, secondary access can always begin with control frame exchanges, for example, using short frames such as Request to Send (RTS) / Allow to Send (CTS) exchanges, Multi-User (MU)-RTS / CTS exchanges, Buffer Status Report Polling (BSRP) / Buffer Status Report (BSR) exchanges, Trigger Frame / UL Response exchanges, new control frames (e.g., frames including anchor channel characteristics or other such information), etc. Control frame exchanges enable polling of non-AP STAs, allowing the AP to know whether a non-AP STA is monitoring the anchor channel before actual data transmission. If the AP does not receive a response from a non-AP STA, the AP knows that the STA may not be usable for transmission and reception via the anchor channel.

[0084] In some implementations, APs with different primary operating channels can form a Multiple AP (MAP) group and a Primary Basic Service Set (M-BSS). APs can negotiate to help each other achieve faster media synchronization recovery. For example, in AP-to-AP transmission / negotiation, all APs in the MAP group can indicate whether they agree to provide a MAP-assisted synchronization recovery process. APs that agree to provide a MAP-assisted synchronization recovery process can follow... Figure 4 The process is shown in the signal diagram 400.

[0085] exist Figure 4 The example network diagram 400 is shown, where AP1 and AP2 are located in a MAP group. In this example, AP1's anchor channel 410 is part of AP2's primary 80 MHz channel 450. AP1 can determine whether it can switch from its primary channel 405 to the anchor channel 410 using the process described herein. AP1 may not update NAV information on the anchor channel 410, and therefore it may need to monitor the anchor channel 410 until its MediumSyncDelay timer 420 reaches 0 (provided that it has not received any PPDU on the anchor channel while monitoring the channel). Meanwhile, AP2 may send one or more short control frames 460 on its primary channel (e.g., the primary 80 MHz channel shown in the dark slot of AP2's bandwidth 450), for example, using non-high throughput (HT) repeated PPDUs, so that AP1, which is monitoring its anchor channel 410 (e.g., a 20 MHz, 40 MHz, or 80 MHz anchor channel), can receive at least one copy. Short frame 460 may include a duration field set to = 0 to indicate that the channel is idle after the frame. In some examples, AP2 may determine to send a short frame when the idle time of AP1's anchor channel is greater than a predefined or advertised threshold.

[0086] In some example embodiments, after the AP switches to the secondary channel / anchor channel, the AP can immediately transmit a short secondary access beacon / announcement frame on the anchor channel. In some embodiments, the short secondary access beacon / announcement frame may carry an indication of any or a combination of the following (1) to (4): (1) The duration for which an AP can remain on the anchored channel; (2) Allowed uplink channel access scheme field, indicating whether one or more uplink access schemes are allowed. Uplink access schemes may include UL-triggered access, CSMA / CA-based uplink access, uplink orthogonal frequency division multiplexing random access (UORA), etc., and may be signaled by predetermined flags or bitmaps, parameter-value pairs or any other such method; (3) The maximum operating channel width on the secondary channel; and / or (4) Identification of any punched subchannel or disabled subchannel on the secondary channel.

[0087] In some embodiments, the AP may determine the dwell time, or the time to remain on or continue using the anchor channel, based on its NAV setting on the primary channel. For example, an AP that switches to the anchor channel and becomes the TXOP holder of the anchor channel may determine the duration of its stay on the anchor channel. In one implementation, the AP may determine the duration of its stay on the anchor channel based on its NAV setting on the primary channel.

[0088] In some cases, the AP may need to switch back to the primary channel before the NAV set on the primary channel ends. In such cases, the AP may not lose media synchronization on the primary channel because it has the correct NAV setting. In some such implementations, non-AP STAs participating in a TXOP on the anchor channel (e.g., participating in transmission or reception) may need to switch back to the primary channel when the TXOP on the anchor channel ends, regardless of their own NAV setting on the primary channel.

[0089] In other examples, a non-AP STA participating in a TXOP (e.g., participating in transmission or reception) on the anchor channel may preferably remain on the anchor channel for a longer period. This could be due to a longer NAV setting on the STA's primary channel, or because the STA may not want to switch back and forth between the primary and anchor channels due to the additional handover delay overhead (e.g., when latency is critical or only a small amount of data needs to be transmitted). If a non-AP STA's NAV might be longer than the TXOP or the expected stay on the anchor channel, the non-AP STA can inform the AP of its NAV setting on the primary channel, or it can simply inform the AP that the STA will remain on the anchor channel.

[0090] Go to Figure 5 The diagram 500 illustrates a method for a WLAN device to switch between a primary channel and an anchor channel according to some example embodiments. In example method diagram 500, an AP and an associated STA can switch from the AP's primary channel to the anchor channel. The AP can obtain the media of the anchor channel and initiate TXOP 505. Based on the AP's NAV settings on the primary channel, the AP can set the duration field of TXOP 505 on the anchor channel. For example, it can set the duration of TXOP 505 on the anchor channel to the end of the NAV on the primary channel, such as... Figure 5As shown. However, in the example shown, for example, for any of the reasons mentioned above, the STA may preferably remain on the anchor channel for a longer period than the duration of TXOP 505. In this case, the STA may send PPDU 510 to the AP via the anchor channel, where PPDU 505 indicates one or a combination of the following options (1) to (3).

[0091] (1) After TXOP 505 ends, the STA can remain on the anchored channel. As an example, this could be a one-bit or several-bit field / subfield carried in the PHY / MAC header along with control / management / data transmission, or a newly defined control / management frame.

[0092] (2) The STA can remain on the anchor channel until the next beacon frame is transmitted from the AP. As an example, if this field / subfield is set, the STA can switch back to the primary channel just before the next beacon frame. Similarly, as an option (1), this can be a one-bit or several-bit field / subfield that can be carried in the PHY / MAC header along with control / management / data transmission, or a newly defined control / management frame.

[0093] (3) The STA can signal to the AP that it can stay on the anchor channel for a specific duration (or for the duration the STA will remain on the anchor channel after TXOP 505). As an example, a field / subfield referred to as the anchor channel duration can be indicated to the AP. Examples of anchor channel duration fields / subfields can indicate microseconds, time units, or a predetermined microsecond length, or any other unit indicating the duration.

[0094] After receiving a frame / PPDU 510 from the STA indicating that the STA will remain on the anchor channel for a longer period than TXOP 505, the AP can send an acknowledgment (ACK) to the STA via the anchor channel (not shown). At the end of TXOP 505 on the anchor channel, the AP can switch back to monitoring the primary channel. The AP can obtain priority over media on the primary channel, and its free channel assessment (CCA) for any or all secondary channels, including the anchor channel, can be idle. For example, the AP can initiate TXOP 515 on a determined idle channel. The AP can know that one or more STAs may still be monitoring the anchor channel, and therefore it can send PPDUs using Orthogonal Frequency Division Multiple Access (OFDMA) mode or Aggregated PPDU (A-PPDU) mode. In some implementations, the AP can allocate downlink (DL) resources to STAs stopped on the anchor channel by including a resource allocation field in the SIG field sent via the secondary channels (including the anchor channel). In such implementations, the SIG fields sent via the primary and secondary channels may be different, allowing the SIG field on the anchor channel to carry more information. In some implementations, the AP can allocate uplink (UL) resources to the STA parked on the anchor channel by including a trigger frame sent via the secondary channel (including the anchor channel).

[0095] refer to Figure 6 This illustrates another method 600 for switching between the primary channel and the anchor channel according to an example embodiment. Figure 6 Example method 600 allows the AP to switch back to the primary channel while the non-AP STA can remain on the anchored channel. Figure 6 The process and setup of method 600 are similar. Figure 5 As shown in the examples, but in this example embodiment, the AP may suggest / instruct non-AP STAs to remain on the anchor channel after the TXOP on the anchor channel ends. In this way, the AP can control the number of STAs remaining on the primary channel and the number of STAs remaining on the secondary channels (including the anchor channel).

[0096] In method 600, after the AP initiates TXOP 605 on the anchor channel / secondary channel, the AP can suggest that one or more STAs remain on the anchor channel for a longer period than the duration of TXOP 605 by sending an anchor channel operation request frame 610. The AP can send a PPDU to the STAs via the anchor channel, and in the PPDU, the AP can indicate one or a combination of the following options (1) to (3): (1) Is it possible to suggest that the STA remain on the anchored channel after TXOP 605 ends? This could be a one-bit or several-bit field / subfield carried in the PHY / MAC header along with control / management / data transmission, or a newly defined control / management frame; (2) Can the STA be advised to remain on the anchor channel until the next beacon frame is transmitted from the AP? If this field / subfield is set, the STA is advised to switch back to the primary channel just before the next beacon frame. This could be a one-bit or several-bit field / subfield that can be carried in the PHY / MAC header along with control / management / data transmission, or a newly defined control / management frame; and / or (3) The duration for which the STA remains in the anchor channel can be suggested. This field / subfield can be referred to as the anchor channel duration (which is in Figure 6 The field / subfield is shown as indicating the length of time (617). The field / subfield can be in microseconds, time units, or any other such units.

[0097] Upon receiving the anchor channel operation request frame 610, each STA can send a response frame 615 to the AP via the anchor channel. The STA can use the response frame 615 to indicate whether it accepts the AP's suggestion, or potentially indicate whether it will remain on the anchor channel for a different period of time.

[0098] At the end of TXOP 605, the AP can switch back to monitoring the primary channel. The AP gains priority over media on the primary channel, and it can determine that the CCA of the secondary channel, including the anchor channel, is idle. The AP can then initiate TXOP 620 on the idle channel. The AP can know that one or more STAs may still be monitoring the anchor channel, and therefore it can send PPDUs via the anchor channel using OFDMA mode or A-PPDU mode. It can allocate DL resources to STAs stopped on the anchor channel by including the resource allocation field in the SIG field sent via the secondary channel (including the anchor channel). In this scenario, the SIG fields sent via the primary and secondary channels may be different, allowing the SIG field to carry more information. The AP can allocate UL resources to STAs stopped on the anchor channel by including a trigger frame sent via the secondary channel (including the anchor channel).

[0099] In various example embodiments, to terminate anchor channel operation, a device (including an AP STA or a non-AP STA) may send an end anchor operation frame (not shown) to indicate that it can immediately switch back to the primary channel after that frame. This frame can be sent via the anchor channel.

[0100] In one implementation, the STA may send another end-anchor operation frame on the main channel to announce its availability on the main channel. In some implementations, the STA may send a short control or action frame on the main channel to announce its availability on the main channel.

[0101] In one example, a method for use in a wireless local area network (WLAN) station (STA) (e.g., an AP STA or a non-AP STA) may include: determining that the first AP will switch from the primary channel to an anchor channel associated with it, based on the unavailability of the primary channel associated with the first AP. Before a timer associated with the first AP expires, the STA receives a frame from a second AP indicating that the anchor channel associated with the first AP is idle. In response to receiving this frame from the second AP, the STA accesses the anchor channel associated with the first AP based on a Carrier Sense Multiple Access Collision Avoidance (CSMA / CA) procedure. Next, the STA sends an initial anchor channel control frame to the second STA to check the availability of the second STA in the anchor channel. The STA may then receive a control response frame indicating that the second STA is available for transmission and / or reception in the anchor channel.

[0102] In various embodiments, the STA can be a first access point (AP), i.e., an AP STA, or a non-AP STA associated with the first AP. According to one embodiment, the first AP and the second AP are associated with a multiple AP group (MAP). In some embodiments, the anchor channel associated with the first AP is located within the primary channel bandwidth associated with the second AP; for example, the anchor channel of the first AP is the same as or part of the primary channel of the second AP. According to various embodiments, the initial anchor channel control frame can be a short control frame, including one of a request to transmit (RTS), allow to transmit (CTS), a buffer status report polling (BSRP) frame, a buffer status report response (BSRR) frame, and a trigger frame, which has a duration field for setting the network allocation vector (NAV), the duration field being set to zero. This allows the STA receiving the control frame on the anchor channel to immediately respond to non-primary channel access on the anchor channel. In one example, the timer associated with the first AP is a synchronization delay timer. In one example, the first AP and the second AP use the same bandwidth.

[0103] According to other embodiments, an example STA / method used in a STA may include receiving an indication from the AP associated with the STA for anchor channel access for non-primary channel access when the AP's primary channel is unavailable. The STA determines that the AP's primary channel is unavailable and monitors the indicated anchor channel.

[0104] The STA receives a control frame from the AP on one of the monitored anchor channels. This control frame indicates that the corresponding anchor channel is idle and the duration for which the AP will remain on the anchor channel. In response to receiving the control frame, the STA transmits a transmission opportunity (TXOP) for anchor channel access via the anchor channel. According to some embodiments, the STA receives a Transmission Opportunity (TXOP) from the AP on the anchor channel for the STA to make a transmission on the anchor channel. In one example, the STA then, during the TXOP, sends an indication to the AP on the anchor channel, for example using an anchor channel duration frame, that the STA will remain on the anchor channel for a longer period after the TXOP than indicated by the AP. In a variant example, before sending the indication that the STA will remain on the anchor channel after the TXOP, the STA receives an indication from the AP on the anchor channel that the STA should remain on the anchor channel after the TXOP, for example, an anchor channel operation request frame.

[0105] In various implementations, the control frame may be one of a Request to Send (RTS), Allow to Send (CTS), Buffer Status Report Polling (BSRP) frame, and trigger frame. In some aspects, the control frame may have a duration field used by the STA to set its Network Allocation Vector (NAV), which is set to zero to allow the STA to immediately contend for access to the anchor channel. In various examples, the anchor channel is a secondary channel for the bandwidth of the channel-bonded AP. In various examples, the anchor channel conforms to the primary channel of the second AP in a multi-AP group (MAP) with APs. In other aspects, this disclosure relates to a Wireless Transmitter Receiver Unit (WTRU); an Access Point (AP); a Station (STA); at least one processor operatively connected to at least one transceiver; a network device; a computing device; and / or an integrated circuit configured to perform any of the methods discussed above, or a non-transitory computer-readable medium comprising instructions that, when executed by a processing device, cause the processing device to perform any of the methods discussed above.

[0106] Although the features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in a computer program, software, or firmware incorporated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM discs and digital multifunction disks (DVDs). The processor associated with the software can be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method for use at a station (STA), the method comprising: Based on the unavailability of the primary channel associated with the first access point (AP), it is determined that the first AP will switch from the primary channel to the anchor channel associated with the first AP; Before the timer associated with the first AP expires, a frame indicating that the anchor channel associated with the first AP is idle is received from the second AP; Based on the Carrier Sense Multiple Access Collision Avoidance (CSMA / CA) process, access is made to the anchored channel associated with the first AP; Send an initial anchor channel control frame to the second STA to check the availability of the second STA in the anchor channel; as well as Receive a control response frame, the control response frame indicating that the second STA can be used for transmission and reception in the anchored channel.

2. The method according to claim 1, wherein, The STA is the first AP or a non-AP STA associated with the first AP.

3. The method according to claim 1, wherein, The first AP and the second AP are associated in a multi-AP (MAP) group.

4. The method according to claim 1, wherein, The anchored channel associated with the first AP is within the main channel bandwidth of the second AP.

5. The method according to claim 1, wherein, The initial anchor channel control frame is one of a request to transmit (RTS) frame, a allow to transmit (CTS) frame, a buffer status report polling (BSRP) frame, a buffer status report response (BSRR) frame, and a trigger frame, wherein the control frame has a duration field set to zero, the duration field being used to set the receiver's network allocation vector (NAV).

6. The method according to claim 1, wherein, The timer associated with the first AP includes a synchronization delay timer.

7. The method according to claim 1, wherein, The first AP and the second AP use the same bandwidth.

8. A station (STA), said station comprising: transceiver; as well as A processor communicatively connected to the transceiver; wherein the transceiver and the processor are configured to: Based on the unavailability of the primary channel associated with the first access point (AP), it is determined that the first AP will switch from the primary channel to the anchor channel associated with the first AP; Before the timer associated with the first AP expires, a frame indicating that the anchor channel associated with the first AP is idle is received from the second AP; Based on the Carrier Sense Multiple Access Collision Avoidance (CSMA / CA) process, access is made to the anchored channel associated with the first AP; Send an initial anchor channel control frame to the second STA to check the availability of the second STA in the anchor channel; and Receive a control response frame, the control response frame indicating that the second STA can be used for transmission and reception in the anchored channel.

9. The STA according to claim 8, wherein, The STA is the first AP or a non-AP STA associated with the first AP.

10. The STA according to claim 8, wherein, The first AP and the second AP are located in a multi-AP (MAP) group.

11. The STA according to claim 8, wherein, The anchored channel associated with the first AP is within the main channel bandwidth of the second AP.

12. The STA according to claim 8, wherein, The initial anchor channel control frame is one of a request to transmit (RTS) frame, a allow to transmit (CTS) frame, a buffer status report polling (BSRP) frame, a buffer status report response (BSRR) frame, and a trigger frame, wherein the control frame has a duration field set to zero, the duration field being used to set the receiver's network allocation vector (NAV).

13. The STA according to claim 8, wherein, The timer associated with the first AP includes a synchronization delay timer.

14. The STA according to claim 8, wherein, The first AP and the second AP use the same bandwidth.

15. A method for use at a station (STA), the method comprising: When the primary channel of the access point (AP) associated with the STA is unavailable, an indication of an anchored channel for non-primary channel access is received from the AP; It was determined that the main channel of the AP was unavailable; Monitor the anchored channel; A control frame is received from the AP on the anchor channel, the control frame indicating that the anchor channel is idle and the duration for which the AP will remain on the anchor channel; as well as In response to receiving the control frame, a transmission for anchor channel access is sent via the anchor channel.

16. The method of claim 15, further comprising: On the anchored channel, receive from the AP a transmission opportunity (TXOP) for the STA to transmit on the anchored channel. as well as During the TXOP, an indication is sent to the AP on the anchor channel that the STA will remain on the anchor channel for a longer period after the TXOP than the indicated duration for which the AP will remain on the anchor channel.

17. The method according to claim 16, wherein, Before sending an indication that the STA will remain on the anchored channel after the TXOP, the method further includes: The STA receives an indication from the AP on the anchored channel that it should remain on the anchored channel after the TXOP.

18. The method according to claim 15, wherein, The control frame includes one of a Request to Send (RTS) frame, a Allow to Send (CTS) frame, a Buffer Status Report Polling (BSRP) frame, and a trigger frame, wherein the control frame has a duration field set to zero, the duration field being used to set the receiver's Network Allocation Vector (NAV).

19. The method according to claim 15, wherein, The anchoring channel is a secondary channel used for channel bonding of the bandwidth of the AP.

20. The method according to claim 19, wherein, The anchoring channel is within the main channel bandwidth of the second AP in the multi-AP (MAP) group containing the AP.

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