Method for beam failure detection and recovery - Patents.com

Abstract

A method and apparatus for beam failure detection and recovery (BFR) are described. The method includes: a wireless transmit / receive unit receiving configuration information including BFR parameter sets having respective candidate beam reference signals (RS), a measurement criterion, and an interference criterion, detecting a beam failure, determining a first BFR parameter set based on a priority of the first BFR parameter set determined based on which panel of a plurality of antenna panels is active or based on a received indication, selecting a candidate beam RS in the set of candidate beam RSs of the first BFR parameter set that satisfies the measurement criterion and the interference criterion, and indicating the selected candidate beam RS, provided that at least one candidate beam RS in the set of candidate beam RSs of the first BFR parameter set satisfies both the measurement criterion and the interference criterion.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 332,180, filed April 18, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] The Third Generation Partnership Project (3GPP) New Radio (NR) for wireless communications defines duplex operation to be implemented. Such technology can provide the basis for improvement of conventional time division duplexing (TDD) operation, for example, by increasing uplink (UL) coverage, improving capacity, and reducing latency. Conventional TDD can be implemented, for example, by splitting the time domain between uplink and downlink. The feasibility of enabling full duplex communication, or more specifically cross division duplex (XDD), which is full duplex communication with no sub-band overlap at the base station (BS) side, within the conventional TDD bands, is under study. Summary of the Invention

[0003] A method and apparatus for beam failure detection and recovery are provided herein. A method of beam failure detection performed by a wireless transmit receive unit (WTRU) may include: receiving configuration information including a plurality of beam failure recovery (BFR) parameter sets, each BFR parameter set including a respective set of candidate beam reference signals (RS), a measurement (RSRP) criterion, and an interference (CLI) criterion; detecting a beam failure; determining a first BFR parameter set from the plurality of BFR parameter sets based on a priority of the first BFR parameter set determined based on which panel is active or based on a received instruction; selecting a candidate beam RS in the set of candidate beam RSs of the first BFR parameter set that satisfies the measurement criterion and the interference criterion, provided that at least one candidate beam RS in the set of candidate beam RSs of the first BFR parameter set satisfies both the measurement criterion and the interference criterion; and sending an instruction indicating the selected candidate beam RS. [Brief description of the drawings]

[0004] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numbers indicate similar elements and in which: [Figure 1A] 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1 is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1C] 1 is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1D] 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Diagram 2] FIG. 2 is a diagram illustrating cross-division duplexing. [Diagram 3] 3 is a diagram illustrating a CLI between a gNB and a WTRU. FIG. 4 is a diagram illustrating a panel switching mechanism in beam failure recovery caused by a CLI in cross division duplexing (XDD) (or dynamic / flexible TDD scheme). [Figure 4A] 1 is a diagram illustrating an example of beam selection between a base station and a WTRU. [Figure 4B] 1 illustrates an example of a CLI between a base station and a WTRU. [Figure 4C] 1 illustrates an example of a CLI between a base station and a WTRU. [Diagram 5] FIG. 1 illustrates an exemplary procedure. [Figure 6] FIG. 1 illustrates an exemplary procedure. [Figure 7] FIG. 1 illustrates an exemplary procedure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. Communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. Communications system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communications system 100 may use 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 Spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0006] 1A, communications 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, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 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, landline or mobile subscriber units, subscription-based units, pagers, mobile 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 wearables, 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 an industrial and / or automated processing chain context), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0007] The communications system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the CN 106, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B (eNode B, eNB), a Home Node B, a home eNode B, a next generation Node B (eNode B, gNB, etc.), a new radio (NR) Node B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0008] The base station 114a may be part of the RAN 104, which may also include other base stations, such as a base station controller (BSC), a radio network controller (RNC), relay nodes, and / or network elements (not shown). The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell, for example, using beamforming to transmit and / or receive signals in desired spatial directions.

[0009] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d via an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0010] More specifically, as noted above, the communications system 100 may be a multiple access system, but may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a and the WTRUs 102a, 102b, 102c of the RAN 104 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communications protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​Uplink (UL) Packet Access (HSUPA).

[0011] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0012] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

[0013] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using a dual connectivity (DC) principle. Thus, the radio interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to and from multiple types of base stations (e.g., eNBs and gNBs).

[0014] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access, WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0015] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as an office, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology, such as IEEE 802.11, to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology, such as IEEE 802.15, to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 through the CN 106.

[0016] The RAN 104 may communicate with the CN 106, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as, for example, different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 may provide call control, charging services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and / or the CN 106 may communicate directly or indirectly with other RANs that use the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may utilize NR radio technology, the CN 106 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0017] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may use the same RAT as the RAN 104 or a different RAT.

[0018] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based wireless technology, and a base station 114b, which may employ an IEEE 802 wireless technology.

[0019] Figure 1B is a system diagram illustrating an example WTRU 102. As shown in Figure 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0020] The processor 118 may 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. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0021] The transmit / receive element 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via the wireless interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0022] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0023] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate over multiple RATs, such as, for example, NR and IEEE 802.11.

[0024] The processor 118 of the WTRU 102 may be coupled to and may receive user-entered data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The 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. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0025] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components in the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0026] 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) regarding the current location of the WTRU 102. In addition to, or in lieu of, information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals being received from two or more neighboring base stations. It will be appreciated that the WTRU 102 may obtain location information by way of any suitable location determination method while remaining consistent with an embodiment.

[0027] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors. The sensor may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor, and the like.

[0028] The WTRU 102 may include a full-duplex radio where the transmission and reception of some or all of the signals (e.g., associated with a particular subframe of both the UL (e.g., for transmission) and DL (e.g., for reception)) may be simultaneous and / or together. The full-duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., via a separate processor (not shown) or via processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio where the transmission and reception of some or all of the signals (e.g., associated with a particular subframe of either the UL (e.g., for transmission) or DL ​​(e.g., for reception)) may be simultaneous and / or together.

[0029] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As mentioned above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also communicate with the CN 106.

[0030] The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, the eNodeB 160a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0031] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG 1C, the eNodeBs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0032] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. 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 the CN operator.

[0033] The MME 162 may be connected to each of the eNodeBs 162a, 162b, 162c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0034] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNodeB handover, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0035] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0036] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0037] Although the WTRU is illustrated in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may use a wired communications interface (e.g., temporarily or permanently) with the communications network.

[0038] In an exemplary embodiment, the other network 112 may be a WLAN.

[0039] A WLAN in infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access or interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic within the BSS and / or outside the BSS. Traffic originating outside the BSS to a STA may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP to be delivered to the respective destination. Traffic between STAs within the BSS may be sent, for example, through the AP, where a source STA may send traffic to the AP, which may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent using a direct link setup (DLS) between the source STA and the destination STA (e.g., directly between them). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad-hoc" communication mode.

[0040] When using an 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a dynamically configured width. The primary channel may be the operating channel of the BSS, but may be used by STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0041] A High Throughput (HT) STA may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0042] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. A 40 MHz and / or 80 MHz channel may be formed by combining multiple adjacent 20 MHz channels. A 160 MHz channel may be formed by combining eight consecutive 20 MHz channels or by combining two non-adjacent 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may pass through a segment parser that may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed and the combined data may be sent to the Medium Access Control (MAC).

[0043] Sub-1 GHz operation modes are supported by 802.11af and 802.11ah. The channel operating bandwidths and carriers 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 White Space (TVWS) spectrum, while 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 Meter Type Control / Machine-Type Communications (MTC), such as MTC devices in macro coverage areas. MTC devices may have limited capabilities, including certain capabilities, for example, support for certain and / or limited bandwidths (e.g., only supporting these). The MTC device may include a battery that has a battery life above a threshold (eg, to maintain a very long battery life).

[0044] WLAN systems that may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that may be designated as a primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be configured and / or limited by the STAs among all STAs operating in the BSS that support the smallest bandwidth operating mode. In an 802.11ah embodiment, the primary channel may be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only) the 1 MHz mode, 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 sensing and / or Network Allocation Vector (NAV) configuration may depend on the status of the primary channel. For example, if a STA (that only supports 1 MHz mode of operation) transmitting to an AP has a busy primary channel, all of the available frequency bands may be considered busy even if most of the available frequency bands are idle.

[0045] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz depending on the country's legal provisions.

[0046] 1D is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As mentioned above, the RAN 104 may use NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also communicate with the CN 106.

[0047] The RAN 104 may include gNBs 180a, 180b, 180c, although it will be understood that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may transmit and / or receive wireless signals to and from the WTRU 102a, for example, using multiple antennas. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or gNB 180c).

[0048] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., including varying numbers of OFDM symbols and / or varying lengths of absolute time durations).

[0049] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed spectrum. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with and connect to a gNB 180a, 180b, 180c while also communicating with and connecting to another RAN, such as an eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0050] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support for network slicing, DC, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0051] 1D 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 the CN operator.

[0052] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may function as a control node. For example, the AMF 182a, 182b may be responsible for user authentication of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions having different requirements), selection of a particular SMF 183a, 183b, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, etc. The AMF 182a, 182b may provide a control plane function for switching between the 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.

[0053] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 106 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 106 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions, such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0054] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policy, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, etc.

[0055] The CN 106 may facilitate communication with other networks. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 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, the WTRUs 102a, 102b, 102c may be connected to the local DNs 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0056] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-102d, base stations 114a-114b, eNodeBs 160a-160c, MME 162, SGW 164, PGW 166, gNBs 180a-180c, AMFs 182a-182b, UPFs 184a-184b, SMFs 183a-183b, DNs 185a-185b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0057] The emulation device may be designed to implement one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device may be directly coupled to another device for the purpose of testing and / or performing tests using over-the-air wireless communication.

[0058] The one or more emulation devices may perform one or more functions, inclusive, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, for example, one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0059] The acronyms and abbreviations used in the preceding and following paragraphs may be defined as follows: Δf Sub-carrier spacing gNB NR NodeB (NR NodeB) AP Aperiodic BFR Beam Failure Recovery BFD-RS Beam Failure Detection-Reference Signal BLER Block Error Rate BWP Bandwidth Part CA Carrier Aggregation CB Contention-Based (e.g., access, channel, resource) CCA Clear Channel Assessment CDM Code Division Multiplexing CG Cell Group CLI Cross Link Interference CoMP Coordinated Multi-Point transmission / reception COT Channel Occupancy Time CP Cyclic Prefix CPE Common Phase Error CP-OFDM (relying on cyclic prefix) Conventional OFDM (OFDM(relying on cyclic prefix) CQI Channel Quality Indicator CN Core Network (e.g., LTE Packet Core or NR Core) CRC Cyclic Redundancy Check CSI Channel State Information CSI-RS Channel State Information-Reference Signal CU Central Unit D2D Device to Device transmission (e.g. LTE Sidelink) DC Dual Connectivity DCI Downlink Control Information DL Downlink DM-RS Demodulation Reference Signal DRB Data Radio Bearer DU Distributed Unit EN-DC E-UTRA-NR Dual Connectivity EPC Evolved Packet Core FD-CDM Frequency Domain-Code Division Multiplexing FDD Frequency Division Duplexing FDM Frequency Division Multiplexing ICI Inter-Cell Interference ICIC Inter-Cell Interference Cancellation IP Internet Protocol LBT Listen-Before-Talk LCH Logical Channel LCID Logical Channel Identity LCP Logical Channel Prioritization LLC Low Latency Communications LTE Long Term Evolution, e.g. 3GPP LTE R8 and later MAC Medium Access Control MAC CE Medium Access Control Control Element NACK Negative ACK MBMS Multimedia Broadcast Multicast System MCG Master Cell Group MCS Modulation and Coding Scheme MIMO Multiple Input Multiple Output MTC Machine-Type Communications MR-DC Multi-RAT Dual Connectivity NAS Non-Access Stratum NCB-RS New candidate beam-Reference Signal NE-DC NR-RAN-E-UTRA Dual Connectivity NR New Radio Dual Connectivity with NR-DC OFDM Orthogonal Frequency-Division Multiplexing OOB Out-Of-Band (radiated) Pcmax Total available WTRU power in a given transmission interval Pcell Primary cell of the master cell group PCG Primary Cell Group PDU Protocol Data Unit PER Packet Error Rate PHY Physical Layer PLMN Public Land Mobile Network PLR Packet Loss Rate PRACH Physical Random-Access Channel PRB Physical Resource Block PRS Positioning Reference Signal Pscell Primary cell of a Secondary cell group PSS Primary Synchronization Signal PT-RS Phase Tracking-Reference Signal QoS Quality of Service (from the physical layer perspective) RAB Radio Access Bearer RAN PA Radio Access Network Paging Area RACH Random Access Channel (or procedure) RAR Random Access Response RAT Radio Access Technology RB Resource Block RCU Radio access network Central Unit RF Radio Front End RE Resource Element RLF Radio Link Failure RLM Radio Link Monitoring RNTI Radio Network Identifier RO Random Access Occasion ROM Read-Only Mode (for MBMS) RRC Radio Resource Control RRM Radio Resource Management RS Reference Signal RTT Round-Trip Time SCG Secondary Cell Group SCMA Single Carrier Multiple Access SCS Sub-Carrier Spacing SDU Service Data Unit SOM Spectrum Operation Mode SP Semi-persistent SpCell Primary cell of a master or secondary cell group. SRB Signaling Radio Bearer SS Synchronization Signal SRS Sounding Reference Signal SSS Secondary Synchronization Signal SUL Supplementary UpLink SWG Switching Gap (in self-contained subframes) TB Transport Block TBS Transport Block Size TCI Transmission Configuration Index TDD Time-Division Duplexing TDM Time-Division Multiplexing TI Time Interval (integer multiple of one or more symbols) TTI Transmission Time Interval (an integer multiple of one or more symbols) TRP Transmission / Reception Point TRPG Transmission / Reception Point Group TRS Tracking Reference Signal TRx Transceiver UL Uplink URC Ultra-Reliable Communications URLLC: Ultra-Reliable and Low Latency Communications V2X Vehicular communications WLAN Wireless Local Area Networks and related technologies (IEEE 802.xx area) XDD Cross Division Duplex

[0060] Terms further defined herein may be referred to using a variety of different designations. Hereinafter, "a" and "an" and similar phrases may be interpreted as "one or more" and "at least one." Similarly, any term ending with the suffix "(s)" may be interpreted as "one or more" and "at least one." The term "may" should be interpreted as "e.g., may."

[0061] A beam may be defined as follows: A WTRU may transmit or receive a physical channel transmission or a reference signal according to at least one spatial domain filter. The term "beam" may be used to refer to a spatial domain filter.

[0062] The WTRU may transmit a physical channel transmission or signal using the same spatial domain filter as that used to receive an RS (e.g., CSI-RS) or SS block. The WTRU transmission may be referred to as the "target" and the received RS or SS block may be referred to as the "reference" or "source." In such a case, the WTRU may be said to transmit the target physical channel or signal according to a spatial relationship to such RS or SS block.

[0063] The WTRU may transmit a first physical channel transmission or signal according to the same spatial domain filter used to transmit a second physical channel transmission or signal. The first and second transmissions may be referred to as the "target" and "reference" (or "source"), respectively. In such a case, the WTRU may be said to transmit the first (target) physical channel or signal according to a spatial relationship to the second (reference) physical channel or signal.

[0064] The spatial relationship may be implicit, set by RRC, or signaled by MAC CE or DCI or another logically equivalent message. For example, the WTRU may implicitly transmit PUSCH transmission and DM-RS of PUSCH according to the same spatial domain filter as the SRS indicated by SRI (indicated by DCI or set by RRC or another logically equivalent message or transmission). In some examples, the spatial relationship may be set by RRC for SRS resource indicator (SRI) or signaled for PUCCH by MAC CE or other logically equivalent means. Such spatial relationship may also be referred to as "beam indication".

[0065] The WTRU may receive a first (target) downlink channel transmission or signal according to the same spatial domain filter or spatial reception parameters as a second (reference) downlink channel or signal. For example, such an association may exist between a physical channel, such as a PDCCH or PDSCH, and its respective DM-RS. When at least the first and second signals are reference signals, such an association may exist when the WTRU is configured with a quasi-colocation (QCL) assumption type D between the corresponding antenna ports. Such an association may be configured as a transmission configuration indicator (TCI) state. The WTRU may be indicated the association between the CSI-RS or SS block and the DM-RS by an index into a set of TCI states configured by the RRC and / or signaled by the MAC CE. Such an indication may also be referred to as a "beam indication."

[0066] Terminology related to TRPs may be used herein as follows: Hereinafter, a TRP (e.g., a transmission / reception point) may be used interchangeably with one or more of a TP (transmission point), an RP (reception point), an RRH (radio remote head), a distributed antenna (DA), a BS (base station), a sector (of a BS), and / or a cell (e.g., a geographic cell area served by a BS), and may still be consistent with the description provided herein. Hereinafter, the term multiple TRPs may be used interchangeably with one or more of an MTRP, an M-TRP, and multiple TRPs, and may still be consistent with the description provided herein.

[0067] Hereinafter, the term "panel" may be used to refer to an antenna panel.

[0068] Hereinafter, the term "subband" is used to refer to a frequency domain resource, which may be characterized by at least one of the following: a set of resource blocks (RBs), a set of resource block sets (RB sets) (e.g., if a carrier has intra-cell guard bands), a set of interlaced resource blocks, a bandwidth portion or part thereof, or a carrier or part thereof. For example, a subband may be characterized by a starting RB and a number of RBs for a set of consecutive RBs in a bandwidth portion. A subband may be defined by the value of the frequency domain resource allocation field and / or a bandwidth portion index.

[0069] Hereinafter, the term "XDD" may be used to refer to a subband-by-subband duplexing scheme (e.g., either UL or DL ​​is used per subband) and may be characterized by at least one of the following: cross-division duplexing (e.g., FDD per subband in the TDD band), a subband-based full-duplexing scheme (e.g., full-duplex as both UL and DL is used / mixed on a symbol / slot, or either UL or DL ​​is used per subband on a symbol / slot), a frequency domain multiplexing (FDM) scheme of DL / UL transmission in the TDD spectrum, a full-duplexing scheme where the subbands do not overlap (e.g., non-overlapping subband full-duplexing), full-duplexing other than on the same frequency (e.g., spectrum sharing, overlapping per subband) full-duplexing scheme, or an advanced duplexing method (e.g., other than (pure) TDD or FDD).

[0070] Hereinafter, the term "dynamic (or flexible) TDD" may be used to refer to a TDD system / cell that can dynamically (and / or flexibly) change / adjust / switch communication direction (e.g., downlink, uplink, or sidelink, etc.) at a time instance (e.g., slot, symbol, subframe, etc.). In one example, in a system employing dynamic / flexible TDD, a component carrier (CC) or a bandwidth part (BWP) may have one single type among "D", "U", and "F" at a symbol / slot based on an indication by a group-common (GC)-DCI (e.g., format 2_0) including a slot format indicator (SFI) and / or based on a tdd-UL-DL-config-common / dedicated configuration. At a given time instance / slot / symbol, a first BS (e.g., cell, TRP) employing dynamic / flexible TDD may transmit a downlink signal to a first WTRU communicating / associating with the first BS based on a first SFI and / or tdd-UL-DL-config set / indicated by the first BS, and a second BS (e.g., cell, TRP) employing dynamic / flexible TDD may receive an uplink signal transmitted from a second WTRU communicating / associating with the second BS based on a second SFI and / or tdd-UL-DL-config set / indicated by the second BS. In some examples, the first WTRU may determine that reception of the downlink signal is interfered with by an uplink signal, and the interference caused by the uplink signal may refer to crosslink interference (CLI) between the WTRUs.

[0071] The WTRU may report a subset of channel state information (CSI) components, which may correspond to at least a CSI-RS resource indicator (CRI), an SSB resource indicator (SSBRI), an indication of the panel used for reception at the WTRU (e.g., panel identity or group identity), measurements such as L1-RSRP, L1-SINR obtained from the SSB or CSI-RS (e.g., cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR), and / or other channel state information such as at least a rank indicator (RI), a channel quality indicator (CQI), a precoding matrix indicator (PMI), a Layer Index (LI), etc.

[0072] Various aspects of beam quality monitoring / radio link monitoring are described herein. The WTRU may use, receive, or be configured with one or more sets of reference signals per BWP to monitor and detect beam failure detection. For example, the term q0 may be used for the beam failure detection set. In another example, the term q0,0 or q0,1 may be used as the beam failure detection set. The beam failure detection set (e.g., set q0, q0,0, or q0,1) may include one or more reference signals, which may be CSI-RS resource configuration indexes and / or SS / PBCH block (SSB) indexes. The reference signals included in the beam failure detection RS set may be the same as the reference signals configured / used / received for radio link monitoring (RLM).

[0073] If the WTRU is not provided / configured with a beam failure detection RS set for the BWP (e.g., set q0, q0,0, or q0,1), the WTRU may determine the respective RS set. For example, the WTRU may determine the RS signals to be included in the beam failure detection RS set for the BWP based on a periodic CSI-RS resource configuration index that the WTRU uses to monitor PDCCH transmissions in the respective CORESETs indicated by the TCI status.

[0074] The WTRU may measure reference signals included in the beam failure detection RS set and estimate the radio link quality accordingly. The WTRU may use one or more thresholds / ranges to monitor and estimate the radio link quality. For example, an out-of-sync threshold (e.g., Q_out) and / or an in-sync threshold (e.g., Q_in) may be used, where the thresholds Q_out and / or Q_in may be used to estimate the quality of the radio link and / or the respective beam. The terms Q_out and Q_in may be used to represent one or more attributes and parameters and their respective values.

[0075] The threshold Q_out may, for example, correspond to an out-of-sync block error rate (BLER_out) and may be used to determine the quality of a radio link and / or beam where a signal transmission may not be reliably received. Alternatively or additionally, the threshold Q_in may correspond to an in-sync block error rate (BLER_in) and may be used to determine the quality of a radio link and / or beam where a signal transmission may be reliably received. BLER_out and / or BLER_in may be explicitly determined by the base station.

[0076] If BLER_out and / or BLER_in are not explicitly determined by the BS, they may be estimated based on one or more parameters. For example, the WTRU may use, receive, or be configured with PDCCH transmission parameters to perform out-of-sync and / or in-sync evaluation. In some examples, the number of control OFDM symbols, aggregation level, ratio of virtual PDCCH RE energy to average SSS RE energy, ratio of virtual PDCCH DMRS energy to average SSS RE energy, BWP in number of PRBs, subcarrier spacing, etc. may be used to determine the BLER_out and / or BLER_in thresholds.

[0077] Examples of PDCCH transmission parameters that may be included when evaluating the Q_out and Q_in thresholds are shown in Tables 1 and 2, respectively. Such tables may provide non-limiting examples of parameters that may be included when evaluating the out-of-sync and in-sync thresholds. One or more of them may be included. The values, numbers of PRBs, and options for each parameter are examples. Other values, numbers of PRBs, or options may be included.

[0078] [Table 1]

[0079] [Table 2]

[0080] Various aspects of beam failure detection are described herein. The WTRU may monitor the beam failure detection RS set in an active BWP. The WTRU may further estimate the quality of the beam / radio link and report the out-of-sync and / or in-sync status. In one example, the WTRU may measure the radio link quality (L1-RSRP) for the SSB and / or CSI-RS in the corresponding beam failure detection RS set. The WTRU may then compare the measurements with respective thresholds to determine, indicate, or detect if a beam failure instance (BFI) has occurred.

[0081] The WTRU may indicate, determine, or be configured with one or more beam failure detection (BFD) counters. Thus, the WTRU may detect beam failure by counting BFI indications. The WTRU may indicate, determine, or be configured with one or more of the following parameters: BFI_Counter (which may be a counter used to count the number of BFIs, which may be initially set to 0 and incremented for each BFI detection), BFI_Max_Count (which may be the maximum value of BFI_Counter that may trigger beam failure detection), BFD_Timer (which may be a timer starting from the first BFI detection). Alternatively or in addition, the parameter BFD_timer may indicate a time period that is considered in determining whether a beam failure has occurred. For example, the BFD_timer may define a duration that the WTRU monitors for the occurrence of one or more conditions. If the timer or time period expires before the BFI_Counter reaches BFI_Max_Count, the beam failure detection procedure is stopped.

[0082] The above parameters are non-limiting examples of parameters that may be included in beam failure detection. One or more of these parameters may be included. Other parameters may also be included.

[0083] In some examples, if a BFI occurs, the WTRU may start and / or restart the BFD_Timer (i.e., monitor one or more conditions within a given duration) and increment the BFI_Counter by 1. If the BFI_Counter reaches BFI_Max_Count, the WTRU may initiate a Beam Failure Recovery (BFR) procedure. Alternatively or additionally, the beam failure detection procedure may be considered to have completed successfully if the duration defined by the parameter BFD_Timer expires but the BFI_Counter has not reached BFI_Max_Count.

[0084] Further aspects of beam failure recovery are described herein. The WTRU may determine, indicate, or trigger beam failure recovery based on the beam failure detection procedure. The WTRU may indicate, determine, or be configured with one or more of the following parameters: BFR_Timer (which may represent the duration to start in the beam failure recovery procedure), RSRP_Threshold (which may be a threshold for RSRP used in beam failure recovery candidateBeamRSList, which may give a list of candidate beam reference signal indexes to be monitored, measured, and selected during beam failure recovery), step power increase parameters (which may include step power increase steps, received preamble target power, or others), or random access parameters (which may include PRACH parameters including preamble index, SSB per RACH opportunity, random access response window, PRACH configuration index, random access opportunity, and SSB association mask index, etc.).

[0085] The WTRU may use, receive, or configure with one or more sets of reference signals per BWP to monitor, measure, and select as resources for beam failure recovery. For example, term q1 may be used for the beam failure recovery set. In another example, term q1,0 or q1,1 may be used as the beam failure recovery set. A beam failure recovery set (e.g., set q1, q1,0, or q1,1) may include one or more reference signals, which may be a CSI-RS resource configuration index and / or an SS / PBCH block (SSB) index. In some examples, the reference signals included in the beam failure recovery RS set may be based on candidateBeamRSList, which is configured as part of the BFR procedure.

[0086] The WTRU may initiate beam failure recovery based on the random access procedure. In some examples, the WTRU may set random access parameters and start monitoring one or more conditions within a duration defined by a parameter such as BFR_Timer and apply a step power increase parameter. The WTRU may monitor and measure one or more of the reference signals from the candidateBeamRSList. The WTRU may determine whether at least one of the SSBs has an SS-RSRP above the respective RSRP_Threshold among the SSBs in the candidateBeamRSList, or whether at least one of the CSI-RSs has a CSI-RSRP above the respective RSRP_Threshold among the CSI-RSs in the candidateBeamRSList. The WTRU may then select the respective reference signal as a candidate new beam / random access resource for the BFR procedure. For example, the term q_new may be used to indicate the new selected beam / random access resource. The WTRU may perform PRACH transmission in each random access resource according to a spatial relationship with the periodic CSI-RS resource configuration or with the SS / PBCH block associated / QCL'd with index q_new.

[0087] Alternatively or additionally, if uplink channel resources (e.g., uplink shared channel resources (UL-SCH)) are available, the WTRU may initiate a MAC-CE (or logically equivalent) beam failure recovery procedure. Thus, the WTRU may generate a BFR MAC-CE or equivalent message and transmit the message using the respective uplink channel resources.

[0088] The WTRU may determine, identify, or be configured with one or more CORESETs corresponding to random access procedures for respective beam failure recovery. In one example, the WTRU may monitor PDCCH transmissions in a search space set for detection of DCI formats having respective CRCs scrambled with a radio network identifier (e.g., C-RNTI or MCS-C-RNTI). The WTRU may monitor the PDCCHs in the search space set and determine the same antenna port quasi-co-location parameters associated with index q_new to receive corresponding PDSCH transmissions.

[0089] If the duration provided, for example by the parameter BFR_Timer, expires and the beam failure recovery procedure fails to complete successfully, the WTRU may trigger a link failure detection and continue with a link failure recovery (LFR) procedure.

[0090] Channel and / or interference measurements are described herein. The WTRU may receive a synchronization signal / physical broadcast channel (SS / PBCH) block. The SS / PBCH block (SSB) may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The WTRU may monitor, receive, or attempt to decode the SSB during initial access, initial synchronization, radio link monitoring (RLM), cell search, cell switching, etc.

[0091] The WTRU may measure and report channel state information (CSI), and the CSI for each connection mode may include or be configured with one or more of the following parameters: CSI reporting amount (e.g., Channel Quality Indicator (CQI), Rank Indicator (RI), Precoding Matrix Indicator (PMI), CSI-RS Resource Indicator (CRI), Layer Indicator (LAI), etc.), CSI reporting type (e.g., aperiodic, semi-persistent, periodic), CSI reporting codebook configuration (e.g., Type I, Type II, Type II port selection, etc.), or CSI reporting frequency.

[0092] The WTRU may be configured with a CSI-RS resource set that includes one or more of the following CSI resource configurations: NZP-CSI-RS resources for channel measurements, NZP-CSI-RS resources for interference measurements, or CSI-IM resources for interference measurements.

[0093] The WTRU may be configured with an NZP-CSI-RS including one or more of the following: NZP CSI-RS resource ID, periodicity and offset, QCL information and TCI state information, or resource mapping (e.g., number of ports, density, CDM type, etc.).

[0094] The WTRU may indicate, determine, or be configured with one or more reference signals. The WTRU may monitor, receive, and / or measure one or more parameters based on each reference signal. For example, one or more of the following may apply: The following parameters are non-limiting examples of parameters that may be included in the reference signal measurements. One or more of these parameters may be included. Other parameters may also be included.

[0095] The reference signal measurements may include SS-RSRP. SS reference signal received power (SS-RSRP) may be measured based on a synchronization signal (e.g., a demodulation reference signal (DMRS) in the PBCH or SSS). It may be defined as a linear average of power contributions across resource elements (REs) carrying the respective synchronization signal. Power scaling for the reference signal may be required when measuring RSRP. If SS-RSRP is used for L1-RSRP, measurements may be achieved based on the CSI reference signal in addition to the synchronization signal.

[0096] The reference signal measurements may include the CSI-RSRP. The CSI-RSRP may be measured based on a linear average of power contributions across resource elements (REs) carrying the respective CSI-RS. The CSI-RSRP measurements may be configured within measurement resources for a configured CSI-RS opportunity.

[0097] The reference signal measurements may include SS-SINR. SS signal-to-noise and interference ration (SS-SINR) may be measured based on a synchronization signal (e.g., DMRS in the PBCH or SSS). SS-RSRP may be defined as the linear average of the power contributions over resource elements (REs) carrying the respective synchronization signals divided by the linear average of the noise and interference power contributions. If SS-SINR is used for L1-SINR, the noise and interference power measurements may be achieved based on resources configured by higher layers.

[0098] The reference signal measurements may include CSI-SINR. The CSI-SINR may be measured based on a linear average of the power contributions over resource elements (REs) carrying the respective CSI-RS divided by a linear average of the noise and interference power contributions. If CSI-SINR is used for L1-SINR, the noise and interference power measurement may be accomplished based on resources configured by higher layers. Otherwise, the noise and interference power may be measured based on resources carrying the respective CSI-RS.

[0099] The reference signal measurements may include RSSI. The received signal strength indicator (RSSI) may be measured based on an average of the total power contributions in a set OFDM symbol and bandwidth. The power contributions may be received from different resources (e.g., co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.).

[0100] The reference signal measurements may include a CLI-RSSI. A crosslink interference received signal strength indicator (CLI-RSSI) may be measured based on an average of total power contributions in a set of OFDM symbols of a set of time and frequency resources. The power contributions may be received from different resources (e.g., crosslink interference, co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.).

[0101] The reference signal measurements may include a sounding reference signal RSRP (SRS-RSRP) that may be measured based on a linear average of power contributions across resource elements (REs) carrying the respective SRSs.

[0102] As described herein, the properties of a grant or allocation may include at least one of the following: frequency allocation, time allocation aspects such as duration, priority, modulation and coding scheme, transport block size, number of spatial layers, number of transport blocks, TCI state, CRI or SRI, repetition count, whether the retransmission scheme is Type A or Type B, whether the grant is a configured grant type 1, type 2 or dynamic grant, whether the allocation is a dynamic allocation or a semi-persistent scheduled (configured) allocation, a configured grant index or semi-persistent allocation index, a configured grant or allocation duration, a channel access priority class (CAPC), and / or any parameters provided in the DCI by the MAC or by the RRC (or by logically equivalent signaling) to schedule the grant or allocation.

[0103] The indication by the DCI may include at least one of the following: an explicit indication by the DCI field or RNTI used to mask the CRC of the PDCCH, and / or an implicit indication such as DCI format, DCI size, CORESET or search space, aggregation level, first resource element (e.g. index of the first control channel element) of the received DCI, where the mapping between properties and values ​​may be signaled by RRC or MAC or logically equivalent messages.

[0104] The term RS may be used interchangeably with one or more of RS resource, RS resource set, RS port, and RS port group. RS may be used interchangeably with one or more of SSB, CSI-RS, SRS, and DM-RS.

[0105] Further context for the embodiments presented herein is provided below. Cross-Division Duplexing (XDD) may be implemented within conventional TDD bands, as shown in FIG. 2. Such implementation of XDD may be conditioned to resolve significant challenges arising due to cross-link interference (CLI). With reference to FIG. 3, in an XDD (or dynamic / flexible TDD) framework, a potential interfering cell 310 may switch from UL to DL or vice versa in communication 313 with a WTRU 330, causing a CLI 311 on a potential interfered BS 320 and a potential CLI 312 on a WTRU 322 to interfere with communication 323 between the interfered WTRU 322 and a gNB 320. In the case of a UL to DL CLI, a CLI 331 from an interfering WTRU 330 may cause a beam failure detection in the interfered WTRU 322. Thus, a beam failure detection and recovery procedure involving a candidate RS beam may need to be selected and performed differently than conventional BFR, since the impact of interference caused by CLI is different from conventional beam detection and recovery. This may result in different WTRU behavior when beam failure is caused by CLI in XDD (or dynamic / flexible TDD).

[0106] 4a-c illustrate an example of beam selection in the presence of CLI. In FIG. 4a, WTRU 410 communicates with base station 420 via preferred beam pairing 424, 412. Other candidate beams for the WTRU are 411 and 413. Candidate beams for the base station are 423 and 425. Additional available base station beams 421, 422, 426, and 427 are also shown. FIG. 4B shows the effect of CLI 430 on the beam arrangement of FIG. 4A. FIG. 4C shows an example beam selection in the presence of CLI 430 interfering with WTRU beams 411, 413, and 412 as shown in FIG. 4A and FIG. 4B. As shown in FIG. 4C, the WTRU selects beam 415 and the base station selects beam 421, which is the least preferred combination in the absence of CLI. In this example, the selected beams 421, 415 work because they are reflected by object 440.

[0107] A summary of at least some example embodiments that are described in further detail is provided in the following paragraphs.

[0108] At least one embodiment may include a panel switching mechanism in BFR triggered by CLI in XDD (or dynamic / flexible TDD), as described below with reference to FIG. 5. In such an embodiment, at 510, the WTRU may report a WTRU capability value (set), which may include a number of panels (e.g., two panels). At 512, the WTRU may receive BFR configuration information, including a list of candidate RS beams (e.g., candidateBeamRSList), a list of monitored beams, a BFR maximum counter threshold (e.g., MaxCount), a set of uplink resources, etc. At 514, the WTRU may determine one or more BFR parameter sets. The BFR parameter set may include a candidate RS beam list (e.g., candidateBeamRSList#1 or candidateBeamRSList#2), a maximum counter threshold (e.g., MaxCount#1 or MaxCount#2), an SRS-RSRP threshold (SRSrsrpThreshold#1 or SRSrsrpThreshold#2), a CLI-RSSI threshold (CLIrssiThreshold#1 or CLIrssiThreshold#2), etc. The BFR parameter set may be associated with a WTRU capability value / set / panel. For example, candidateBeamRSList#1 may be associated with WTRU capability set / panel 1, and candidateBeamRSList#2 may be associated with WTRU capability set / panel 2. The candidate RS beam lists may be identified, for example, explicitly (i.e., different / separate lists may be identified) or implicitly (i.e., the WTRU may group candidate RS beams based on a prioritization (e.g., based on panel ID)).

[0109] The WTRU may monitor the beams in the watch list, and if a beam failure is detected more than a threshold number of times, as indicated by decision point 518, the WTRU may determine whether the BFD is due to a CLI. If the BFD is due to a CLI, then one or more of the following may be applied: the WTRU may select a first BFR parameter set based on a priority (e.g., based on an active panel) at 520, the WTRU may start a first BFR counter (e.g., BFRcounter#1) at 522, and / or the WTRU may measure SRS-RSRP and / or CLI-RSSI based on a candidate RS beam selected in a first candidate RS beam list (e.g., candidateBeamRSList#1) at 524 and compare to a first threshold (e.g., SRSrsrpThreshold#1 and / or CLIrssiThreshold#1) at 526. If the measured resources are lower than the respective thresholds, the WTRU may transmit a message indicating a beam failure recovery request (BFRR) (e.g., a PRACH transmission) using the selected candidate RS beam at 528, and may then monitor PDCCH transmissions in the BFR-CORESET at 530 and establish a corresponding new beam pair link at 534. Otherwise, if a first BFR counter (e.g., BFRcounter#1) has not reached a first maximum counter threshold (e.g., MaxCount#1) at 542, the WTRU selects another candidate RS beam from the first list (e.g., candidateBeamRSList#1) at 540.

[0110] If the first BFR counter (e.g., BFRcounter#1) reaches a first maximum counter threshold (e.g., MaxCount#1) at 542, the WTRU may switch to a second BFR parameter set at 540. One or more of the following conditions, steps, or procedures may occur: the WTRU may reset the BFR counter or may start a second BFR counter (e.g., BFRcounter#2) at 552. The WTRU may measure SRS-RSRP and / or CLI-RSSI based on a candidate RS beam selected in the second candidate RS beam list (e.g., candidateBeamRSList#2) and compare with a second threshold (e.g., SRSrsrpThreshold#2 and / or CLIrssiThreshold#2) at 524.

[0111] At 526, if the measured resources are lower than the respective thresholds, at 528, the WTRU may transmit a message indicating a beam failure recovery request (BFRR) (e.g., a PRACH transmission) using the selected candidate RS beam, and then at 530, may monitor PDCCH transmissions in the BFR-CORESET and establish a corresponding new beam pair link.

[0112] Otherwise, if the second BFR counter (e.g., BFRcounter#2) has not reached a second maximum counter threshold (e.g., MaxCount#2) at 544, the WTRU may select another candidate RS beam from the second list (e.g., candidateBeamRSList#2) at 550. If all BFR counters have reached their respective maximum counter thresholds, the WTRU may switch to a contention-based random access procedure at 546.

[0113] At least one embodiment described herein with reference to FIG. 6 may concern an independent candidate beam RS list for CLI-triggered beam failure recovery. In an example embodiment, at 610, the WTRU may be configured with a first list (e.g., candidateBeamRSList) for conventional BFR and a second candidate beam RS list (e.g., candidateBeamRSList-CLI) to be used when BFR is triggered by CLI in XDD (or dynamic / flexible TDD). The list may include one or more indications of SSB and / or CSI-RS that may be in different directions (e.g., the beams in candidateBeamRSList-CLI may be in a different direction than the direction affected by the interfering WTRU).

[0114] If a BS in a DL subframe switches to UL, the BS may notify other BSs / WTRUs of the switch, e.g., if there is inter-cell coordination, the interfering BS may notify the potentially interfered BS through a backhaul connection. Otherwise, if there is no inter-cell coordination, the interfering BS may transmit a specific signal within a window. The WTRU may monitor the signal and detect the switch. The BS may monitor the signal and notify the WTRU that it may be affected by the switch.

[0115] If a BFR is detected (at 612), the WTRU may determine at 614 whether it was due to a CLI, for example based on a combination of RSRP, L1-SINR, CLI-RSSI, and / or SRS-RSRP, according to one or more methods or procedures described in further detail herein.

[0116] If the BFR was triggered by a CLI, then the WTRU may select an SSB or CSI-RS from among the second list of reference signals (e.g., candidateBeamRSList-CLI) at 616. The WTRU may then proceed to a beam failure recovery request. If the BFR was not triggered by a CLI, then the WTRU may select an SSB or CSI-RS from among the first list of reference signals (e.g., candidateBeamRSList) at 618. The WTRU may then proceed to a beam failure recovery request.

[0117] At least one embodiment may relate to dynamic beam failure detection and recovery caused by a CLI. In some embodiments, the WTRU may be configured to measure and report the SRS-RSRP based on the SRS received from a potential interfering WTRU. The SRS-RSRP report may be used at the BS to set and select a candidate beam RS list in case the beam failure is caused by a CLI (e.g., candidateBeamRSList-CLI or candidateBeamRSList#2 in WTRU capability set 2). The WTRU may further process the SRS-RSRP in terms of power and / or beam direction. The WTRU may determine the type of BFD and whether it is caused due to a CLI (based on a combination of virtual PDCCH BLER, L1-RSRP, L1-SINR, CLI-RSSI, and / or SRS-RSRP measurements). In an embodiment, the following BFD types may be applied: BFD Type 1 (Virtual BLER > Threshold, CLI < Threshold), BFD Type 2 (Virtual BLER > Threshold, CLI > Threshold), BFD Type 3 (Virtual BLER < Threshold, CLI > Threshold), or BFD Type 4 (Virtual BLER < Threshold, CLI < Threshold).

[0118] The WTRU may report and / or recommend candidate RS (SSB or CSI-RS) beams to be included in the candidate beam RS list when beam failure is caused by CLI (e.g., candidateBeamRSList-CLI or candidateBeamRSList#2 in WTRU capability set 2). The WTRU may determine the candidate RS beams based on, for example, a combination of L1-RSRP and CLI measurements. From the candidate RS beams, the WTRU may perform a best beam selection based on a combination of L1-RSRP and CLI measurements. If the WTRU determines that the BFR is due to CLI and that the UL-SCH is available, the WTRU generates and reports a BFR MAC CE to indicate beam failure detection, an index to an SSB or CSI-RS with RSRP above a threshold, etc.

[0119] A panel switching mechanism in BFR is described herein. The WTRU may determine and report a respective WTRU capability value / set (e.g., based on WTRU panel-related parameters). In some examples, the WTRU may include a parameter for the number of panels (e.g., two panels) that the WTRU may use to transmit and / or receive as a WTRU capability value / set report. In some examples, the WTRU may include a parameter for the maximum supported number of layers (e.g., four layers) for a WTRU panel (e.g., per WTRU panel, or for all WTRU panels, etc.) as a WTRU capability value / set report. In one example, the WTRU may include a parameter for the number of transmit chains (or transmit / receive units, etc.) for a WTRU panel (e.g., per WTRU panel, or for all WTRU panels, etc.) as a WTRU capability value / set report. In some examples, the WTRU may include a parameter for the number of maximum supported SRS ports (or configurable SRS ports) for a WTRU panel (e.g., per WTRU panel, or for all WTRU panels, etc.) as a WTRU capability value / set report.

[0120] As used in this specification, the term WTRU panel may be used interchangeably with one or more of a WTRU antenna group, a WTRU antenna port group, an entity / block / component capable of performing transmission and / or reception, and an entity / block / component capable of independent power control and / or timing control.

[0121] According to the description provided herein, for example, a WTRU may use / have / use, for example, two WTRU panels (e.g., WTRU panel 1 and WTRU panel 2 for communication with a BS, which may be reported based on a WTRU capability value / set report), although the embodiments and processes discussed may be equally used in cases having more than two WTRU panels.

[0122] In an embodiment, the WTRU may use / activate WTRU-Panel1 for communication with the BS, e.g., based on the outcome / result of an initial access procedure, based on instructions / configuration from the BS, and / or based on an active WTRU-panel selection initiated / directed / driven / triggered by the WTRU. In some examples, using WTRU-Panel1 for communication with the BS may imply that the WTRU can use WTRU-Panel1 for at least one of the following: DL control channel reception, DL data / shared channel reception, DL RS reception, UL control channel transmission, UL data / shared channel transmission, and UL RS transmission.

[0123] The WTRU may determine, identify, or receive configuration information for beam failure monitoring and detection. The WTRU may measure beam quality based on a reference signal associated with the beam. For example, the WTRU may perform one or more of the following procedures: The WTRU may measure channel quality based on at least one of SS-RSRP, CSI-RSRP, L1-RSRP, or other metrics. The WTRU may measure interference power based on at least one of SRS-RSRP, CLI-RSSI, CSI-RS interference measurement resource (IMR), or other metrics. The WTRU may measure channel-to-interference quality ratio using at least one of SS-SINR, CSI-SINR, L1-SINR, etc. The WTRU may measure radio link quality based on PDCCH transmission parameters, a ratio of virtual PDCCH RE energy to average SSS RE energy (e.g., virtual BLER), etc. The WTRU may determine, identify, or receive configuration information for beam failure recovery (BFR). In some examples, the WTRU may receive BFR configuration information including a list of candidate RS beams (eg, candidateBeamRSList), a BFR maximum counter threshold (eg, MaxCount), a set of uplink resources, or other parameters.

[0124] In the following, the parameters described above, such as the candidate RS beam list, the maximum counter threshold, the SS-RSRP threshold, the CSI-RSRP threshold, the SRS-RSRP threshold, and the CLI-RSSI threshold, may be referred to as BFR parameters. A particular combination of such parameters may be referred to as a "BFR parameter set."

[0125] In an embodiment, the WTRU may use, define, determine, or be configured with one or more BFR parameter sets. The BFR parameter sets may include a candidate RS beam list (e.g., candidateBeamRSList#1 or candidateBeamRSList#2), a maximum counter threshold (e.g., MaxCount#1 or MaxCount#2), an SRS-RSRP threshold (SRSrsrpThreshold#1 or SRSrsrpThreshold#2), a CLI-RSSI threshold (CLIrssiThreshold#1 or CLIrssiThreshold#2), etc. An example embodiment is described below with reference to FIG. 4.

[0126] In embodiments, the BFR parameter sets may be associated with WTRU capability values, sets, and / or WTRU panels. In some examples, candidateBeamRSList#1 may be associated with (e.g., may be configured / indicated for use with) WTRU capability set / panel 1, and candidateBeamRSList#2 may be associated with (e.g., may be configured / indicated for use with) WTRU capability set / panel 2.

[0127] For the indication of the BFR parameter set, one or more of the following methods may be used: Referring to Figure 7, at 710, an explicit indication may be used in which the WTRU may receive configuration information indicating a separate or different BFR parameter list (e.g., based on association with a WTRU capability value, set, or WTRU panel).

[0128] An implicit indication may be used in which the WTRU may receive configuration information indicating one or more BFR parameters, from which the WTRU may determine, define, or identify different or separate BFR parameter sets (e.g., each corresponding to a respective WTRU capability value, set, or WTRU panel).

[0129] The WTRU may group the BFR parameters into a BFR parameter set based on the prioritization. In some examples, the WTRU may determine the prioritization based on, for example, a WTRU panel ID associated with the BFR parameters. Thus, the WTRU may group the BFR parameters into a BFR parameter set based on the respective WTRU panel ID. For example, the WTRU may determine the BFR parameter set based on the candidate RS beams, and the WTRU may group the candidate RS beams based on the prioritization (e.g., based on the WTRU-panel ID).

[0130] In some embodiments, the WTRU may monitor a reference signal from a beam failure detection set (e.g., q0 list), for example, based on WTRU panel 1 (as the currently activated / used WTRU panel). At 712, if a beam failure is detected, the WTRU triggers a beam recovery procedure.

[0131] A beam recovery procedure (BRP) is described herein. The WTRU may determine a beam failure detection (e.g., based on WTRU panel 1 (as the currently activated / used WTRU panel)) and trigger a beam recovery procedure accordingly. The WTRU may determine whether the beam failure detection is caused due to an interference signal (e.g., due to crosslink interference (CLI)) according to one or more schemes described herein, and the effect of the CLI may degrade (downlink) reception performance when receiving a downlink signal via (using) WTRU panel 1.

[0132] One or more of the following conditions may apply: The WTRU may determine the first BFR parameter set (e.g., in response to determining that the first BFR parameter set is associated with WTRU panel 1 (as the currently activated / used WTRU panel). For example, with reference to FIG. 7, at 714, the WTRU may select a BFR parameter set (e.g., the first BFR parameter set) based on a prioritization (e.g., a panel ID of the panel that was actively in use when the beam failure was detected).

[0133] The WTRU may determine, identify, or use the first candidate RS beam list from the first BFR parameter list (e.g., candidateBeamRSList#1). In some examples, the BS may configure, activate, and indicate the first candidate RS beam list associated with WTRU panel 1 based on an efficient beam management strategy / procedure, e.g., based on a recent beam report from the WTRU informing the BS of one or more preferred RS beam indexes each with a corresponding WTRU panel ID (e.g., WTRU capability value / set index) reported together. In response to the recent beam report, the BS may activate, indicate, and update one or more preferred RS beam indexes included in the first candidate RS beam list linked / associated with WTRU panel 1 (e.g., via WTRU capability value / set index, WTRU panel ID, etc.). This may provide benefits in terms of beam management efficiency and improved robustness in beam failure related procedures in that the BS may control the WTRU behavior in initially searching for a preferred RS beam in the first candidate RS beam list based on the configured / indicated BFR procedure.

[0134] The WTRU may start a first BFR counter (eg, BFRcounter#1) based on a maximum counter threshold (eg, MaxCount#1) in the first BFR parameter set.

[0135] With reference to FIG. 7, at 716, the WTRU may select a candidate RS beam from the first candidate RS beam list. In an example, the WTRU may be configured with two or more candidate RS beam lists (e.g., one each associated with a respective WTRU panel), but the WTRU may first search through / in the candidate RS beam list (e.g., the first candidate RS beam list) associated with the currently activated / used WTRU panel (e.g., WTRU panel 1) and may not first search through / in the second candidate RS beam list (e.g., if the WTRU panel associated with the second candidate RS beam is not currently activated / used / preferred, etc.). This may provide benefits in terms of beam management efficiency and improved robustness in beam failure related procedures in that the BS may control the WTRU behavior in first searching for a preferred RS beam in the first candidate RS beam list based on the configured / indicated BFR procedure.

[0136] The WTRU may measure the radio link and / or beam quality (e.g., SS-RSRP, CSI-RSRP, signal-to-interference-and-noise ratio (SINR) value, SSB-based SINR, CSI-SINR, etc.) of the selected candidate RS beam.

[0137] The WTRU may compare the channel quality measurement to a respective channel / beam quality threshold from the first BFR parameter list (e.g., SSB-RSRP threshold, CSI-RSRP threshold, SINR threshold, SSB-based SINR threshold, CSI-SINR threshold, etc.).

[0138] In some cases, if the measured channel / beam parameters exceed the respective thresholds (or in addition to or with the above measurements, e.g., eventually combined together to determine an action (e.g., candidate beam selection / report / request) during the BFR procedure), the WTRU may measure interference based on an interference measurement reference signal and resource (e.g., at least one of SRS-RSRP, CLI-RSSI, CSI-RS interference measurement resource (IMR), predefined / preconfigured interference measurement method based on configured / indicated RS, etc.). In some examples, the WTRU may measure interference (i.e., SRS-RSRP) based on configured / indicated SRS signal / configuration and in configured / indicated time and frequency resources. In one example, the configured / indicated SRS signal / configuration may correspond to an SRS being transmitted (e.g., to be transmitted) from a second WTRU (e.g., a (potential) interfering WTRU, a WTRU in a neighboring cell / TRP, etc.). This may provide the benefit that such CLI-related measurements may be taken into account in deriving / selecting a preferred candidate beam as part of the BFR procedure. In some examples, the WTRU may measure the CLI-RSSI based on a configured reference signal and at configured time and frequency resources, which may provide a benefit in that the WTRU may apply / use the CLI-RSSI measurement in deriving / selecting a preferred candidate beam as part of a BFR procedure, e.g., with respect to overall interference levels including CLI effects, etc.

[0139] The WTRU may compare the channel quality measurement parameters and the interference measurement parameters. In some examples, the WTRU may compare the interference measurements to respective channel / beam interference thresholds (e.g., CLI-RSSI threshold, SRS-RSRP threshold, CSI-IMR threshold, etc.) from the first BFR parameter list. In some examples, the WTRU may estimate a virtual measurement (e.g., a virtual BLER) in light of comparing the channel / beam quality measurements and the interference measurements (e.g., based on a ratio of the channel quality measurement to the interference measurement).

[0140] With reference to FIG. 7, at 720, the WTRU may determine whether the candidate beam is a preferred beam to be selected for performing a beam recovery procedure. The WTRU may report one or more of the preferred candidate beams. In an embodiment, the indication may be by MAC-CE or CF-RACH. The WTRU may receive a confirmation message from the BS (e.g., by receiving a PDCCH in the respective BFR CORESET), indicating, for example, that the beam is preferred or not preferred.

[0141] The WTRU may determine that a candidate beam is not a preferred beam. For example, a beam may not be selected as a preferred beam due to one or more of the following conditions: a low channel quality measurement compared to a respective threshold, a high interference measurement compared to a respective threshold, a low ratio of channel quality measurement to interference measurement compared to a respective threshold, or the WTRU has not received confirmation from the BS on the reported preferred candidate beam (e.g., no PDCCH transmissions have been received via the BFR CORESET, or no other downlink signal has been received, or a given duration has expired before receiving confirmation, etc.).

[0142] The WTRU may determine the next candidate beam. One or more of the following steps may be performed: The WTRU may increment a first BFR counter (e.g., BFRcounter#1) by 1. The WTRU may compare the first BFR counter with a maximum counter threshold (e.g., MaxCount#1) in the first BFR parameter set.

[0143] If the first BFR counter has not reached the maximum counter threshold in the first BFR parameter set, the WTRU may determine and / or select another candidate RS beam from the first candidate RS beam list, as shown in FIG. 7 at 718.

[0144] The WTRU may measure channel quality parameters and interference parameters in light of applying at least one of the above-mentioned behaviors / procedures / steps to the selected candidate beam (eg, based on the above-mentioned steps).

[0145] If a BFR-related counter (e.g., a first BFR counter) reaches a maximum counter threshold in a first BFR parameter set, the WTRU may follow a procedure to search for other candidate beam RSs (e.g., in a second candidate RS beam list and / or apply automatic panel switching).

[0146] A method for automatic panel switching is described herein. A WTRU may determine that a first BFR counter associated with a first BFR parameter set and / or a first WTRU panel (e.g., BFRcounter#1) has reached a first maximum counter threshold (e.g., MaxCount#1). Thus, the WTRU may decide to switch to a second BFR parameter set (e.g., a second WTRU panel). One or more of the following steps or procedures may be performed:

[0147] The WTRU may determine, identify, or use a second candidate RS beam list from a second BFR parameter list (eg, candidateBeamRSList#2).

[0148] For example, upon determining that a first BFR counter (e.g., associated with a first WTRU panel) has reached a threshold (e.g., a first maximum counter threshold), the WTRU may reset the BFR counter or start a second BFR counter (e.g., BFRcounter#2) based on a maximum counter threshold (e.g., MaxCount#2) in a second BFR parameter set.

[0149] The WTRU may select a candidate RS beam from a second list of candidate RS beams (eg, associated with a second WTRU panel, which may be based on at least one of the WTRU capability values / set).

[0150] The WTRU may measure the radio link and / or beam quality (e.g., SS-RSRP, CSI-RSRP, SINR value, SSB-based SINR, CSI-SINR, etc.) of the selected candidate RS beam.

[0151] The WTRU may compare the channel quality measurement with a respective channel / beam quality threshold from the second BFR parameter list (e.g., SSB-RSRP threshold, CSI-RSRP threshold, SINR threshold, SSB-based SINR threshold, CSI-SINR threshold, etc.).

[0152] If the measured channel / beam parameters exceed the respective thresholds (or in addition to or with the above measurements, e.g., eventually combined together to determine an action (e.g., candidate beam selection / report / request) during the BFR procedure), the WTRU may measure interference based on an interference measurement reference signal and resource (e.g., at least one of SRS-RSRP, CLI-RSSI, CSI-RS interference measurement resource (IMR), predefined / preconfigured interference measurement method based on configured / indicated RS, etc.). In some examples, the WTRU may measure the SRS-RSRP based on a configured / indicated SRS signal / configuration and in a configured / indicated time and frequency resource. In some examples, the configured / indicated SRS signal / configuration may correspond to an SRS being transmitted (e.g., to be transmitted) from a second WTRU (e.g., a (potential) interfering WTRU, a WTRU in a neighboring cell / TRP, etc.). This may provide the benefit that such CLI-related measurements may be taken into account in deriving / selecting a preferred candidate beam as part of the BFR procedure. In some examples, the WTRU may measure the CLI-RSSI based on a configured reference signal and at configured time and frequency resources. This may provide an advantage that the WTRU may apply / use the CLI-RSSI measurement when deriving / selecting a preferred candidate beam as part of a BFR procedure, e.g., with respect to overall interference levels including CLI effects, etc.

[0153] The WTRU may compare the channel quality measurement parameters and the interference measurement parameters. In some examples, the WTRU may compare the interference measurements to respective channel / beam interference thresholds from the second BFR parameter list (e.g., CLI-RSSI threshold, SRS-RSRP threshold, CSI-IMR threshold, etc.). In some examples, the WTRU may estimate a virtual measurement (e.g., a virtual BLER) in light of comparing the channel / beam quality measurements and the interference measurements (e.g., based on a ratio of the channel quality measurement to the interference measurement).

[0154] The WTRU may determine whether the candidate beam is a preferred beam to be selected for performing a beam recovery procedure.

[0155] The WTRU may report one or more of the preferred candidate beams. The WTRU may receive a confirmation from the BS (e.g., by receiving a PDCCH in the respective BFR CORESET or by receiving another logically equivalent message). In response to receiving the confirmation, the WTRU may start or be configured to start using the second WTRU panel (e.g., switch to, update, and / or deactivate, start using, etc. the first WTRU panel) to communicate with the BS based on (using) the candidate beam. Using the second WTRU panel based on the candidate beam may include communicating with the BS based on a second spatial domain filter determined based on the candidate beam included in the second candidate RS beam list and that may be confirmed by the BS based on the confirmation. This may provide benefits in terms of overhead and delay reduction for WTRU panel switching / selection procedures in that the WTRU may change / switch its panel (from the first WTRU panel to the second WTRU panel) for communication with the BS without, for example, a separate / explicit WTRU panel switching indication and / or procedure based on at least one embodiment or solution described herein. This can provide benefits in terms of automatic WTRU panel switching.

[0156] The WTRU may determine that a candidate beam is not a preferred beam. For example, a beam may not be selected as a preferred beam due to one or more of the following: a low channel quality measurement compared to a respective threshold, a high interference measurement compared to a respective threshold, a low ratio of channel quality measurement to interference measurement compared to a respective threshold, or if the WTRU does not receive confirmation from the BS on a reported preferred candidate beam (e.g., if it does not receive a PDCCH via a BFR CORESET or another logically equivalent message, or if a given duration expires before receiving confirmation, etc.).

[0157] The WTRU may determine the next candidate beam. One or more of the following steps or procedures may be performed: The WTRU may increment a second BFR counter (e.g., BFRcounter#2) by one. The WTRU may compare the second BFR counter with a maximum counter threshold (e.g., MaxCount#2) in the second BFR parameter set. If the second BFR counter has not reached the maximum counter threshold in the second BFR parameter set, the WTRU may determine and / or select another candidate RS beam from the second candidate RS beam list. The WTRU may measure channel quality parameters and interference parameters in light of applying at least one of the above-mentioned behaviors / procedures / steps to the selected candidate beam (e.g., based on the above-mentioned steps).

[0158] If the second BFR counter reaches a maximum counter threshold in the second BFR parameter set, the WTRU may follow procedures for a contention-based random access procedure.

[0159] Embodiments including independent BFR parameter sets for beam failure recovery are described herein. In some embodiments, a WTRU may use, determine, or be configured with at least two BFR parameter sets, and each BFR parameter set may be associated with an operation mode. For example, when a WTRU determines and / or identifies a first operation mode, it may use, determine, or identify a BFR parameter setting based on the first BFR parameter set. Alternatively or in addition, when a WTRU determines and / or identifies a second operation mode, it may use, determine, or identify a BFR parameter setting based on the second BFR parameter set. Parameters that affect operation modes are defined as follows:

[0160] The parameters may include a duplexing mode (e.g., TDD, FDD, or XDD). For example, if the WTRU is operating in a TDD mode, the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU is operating in an FDD mode, the WTRU may determine the BFR parameters based on a second BFR parameter set. Further, if the WTRU is operating in an XDD mode in the respective subband, the WTRU may determine the BFR parameters based on a third BFR parameter set.

[0161] The parameters may include a cause of the BFD. For example, if the WTRU determines that the BFD was caused by beam quality degradation (e.g., due to beam blocking), the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU determines that the BFD was caused by an interference signal (e.g., CLI in XDD), the WTRU may determine the BFR parameters based on a second BFR parameter set.

[0162] The parameters may include a range of subbands. For example, if the WTRU determines that the WTRU is not affected / interfered with by a CLI in XDD operation in the respective subband, the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU determines that the WTRU may be affected / interfered with by a CLI from a potential interfering cell, BS, and / or WTRU in XDD operation in the respective subband, the WTRU may determine the BFR parameters based on a second BFR parameter set.

[0163] The parameters may be determined based on a beam failure recovery procedure. For example, if the WTRU is operating in a full BFR procedure, the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU is operating in a partial BFR procedure, the WTRU may determine the BFR parameters based on a second BFR parameter set.

[0164] The parameters may be based on a licensing regime. For example, if the WTRU is operating with shared spectrum channel access, the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU is operating without shared spectrum channel access, the WTRU may determine the BFR parameters based on a second BFR parameter set.

[0165] The parameters may be based on a use case (e.g., sidelink, NTN, etc.). For example, if the WTRU determines a first use case, the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU determines a second use case, the WTRU may determine the BFR parameters based on a second BFR parameter set.

[0166] The parameters may be based on WTRU type barring (e.g., access barring for a particular WTRU type). For example, a first type WTRU (e.g., a WTRU with limited capabilities including reduced receive antennas, a smaller supported maximum bandwidth, a lower maximum transmit power) may determine BFR parameters based on a first BFR parameter set if the WTRU is not allowed to access the cell. Otherwise, the first type WTRU may determine BFR parameters based on a second BFR parameter set if it is allowed to access the respective cell.

[0167] The parameters may be based on, for example, the beam, the TCI, the TRP, and / or one or more other parameters for the WTRU panel. For example, the WTRU may determine the BFR parameters based on a first BFR parameter set upon a determination (e.g., based on at least one of the embodiments of the present disclosure) that at least one of a first beam index, a first TCI, a first TRP index / ID, and / or a first WTRU panel index / ID is associated with a first BFR parameter set (e.g., based on an explicit instruction from the BS). The WTRU may determine the BFR parameters based on a second BFR parameter set upon a determination (e.g., based on at least one of the embodiments of the present disclosure) that at least one of a second beam index, a second TCI, a second TRP index / ID, and / or a second WTRU panel index / ID is associated with a second BFR parameter set (e.g., based on an explicit instruction from the BS).

[0168] The parameters may be based on support for a particular capability in the network (e.g., power saving, carrier aggregation, DRX, etc.). For example, if the WTRU determines a first capability in the network, the WTRU may determine the BFR parameters based on a first BFR parameter set. If the WTRU determines a second capability in the network, the WTRU may determine the BFR parameters based on a second BFR parameter set.

[0169] In some examples, the WTRU may be configured with a first BFR parameter set that includes one or more first candidate beam failure recovery reference signal (CBFR-RS) lists (e.g., candidateBeamRSList). The WTRU may be configured with a second BFR parameter set that includes one or more second CBFR-RS lists (e.g., candidateBeamRSList-CLI). In one example, the second BFR parameter set and the respective CBFR-RS list may be used when BFD is triggered by a CLI in an XDD. One or more of the following steps or procedures may be performed.

[0170] The WTRU may use, determine, or be configured with a first BFR parameter set having a first set q1 and a second BFR parameter set having a second set q1_CLI for the single-TRP scheme, which are provided based on candidateBeamRSList and candidateBeamRSList_CLI, respectively. The WTRU may use, determine, or be configured with a first BFR parameter set including first two sets q1,0 and q1,1 for the multiple-TRP scheme, which are provided based on candidateBeamRSList1 and candidateBeamRSList2, respectively. The WTRU may use, determine, or be configured with a second BFR parameter set including second two sets q1,0_CLI and q1,1_CLI for the multiple-TRP scheme, which may be provided based on candidateBeamRSList1_CLI and candidateBeamRSList2_CLI, respectively, for example.

[0171] In some examples, the WTRU may be configured with a first BFR parameter set including one or more first parameters (e.g., a maximum counter threshold (e.g., MaxCount), an SRS-RSRP threshold (SRSrsrpThreshold), a CLI-RSSI threshold (CLIrssiThreshold), etc.). The WTRU may be configured with a second BFR parameter set including one or more second parameters (e.g., a maximum counter threshold (e.g., MaxCount_CLI), an SRS-RSRP threshold (SRSrsrpThreshold_CLI), a CLI-RSSI threshold (CLIrssiThreshold_CLI), etc.). In some examples, the second BFR parameter set may be used when BFD is triggered by a CLI in XDD.

[0172] Embodiments including potential CLI indications are described herein. In some embodiments, a WTRU may determine whether potential crosslink interference (CLI) in a subband may affect the quality of the WTRU's beam and / or channel. For example, potential CLI may be due to a change in transmission direction in a neighboring cell in an XDD (or dynamic / flexible TDD) framework. For example, a change in signal transmission direction from downlink (DL) to uplink (UL) in a neighboring cell may cause a CLI from a potential interfering WTRU from UL to DL to an interfered WTRU in a serving cell with DL transmission.

[0173] The WTRU may determine a potential CLI based on, for example, an explicit or implicit indication. In the case of an explicit indication, the WTRU may receive information indicating a trigger or indication (e.g., via a DCI, MAC-CE, or logically equivalent message) that a potential CLI may exist or may affect the quality of the WTRU's channel and / or beam in the respective subband. In some examples, a potential interfering BS / cell may indicate to a serving BS / cell that the transmission direction is about to change in a subband (e.g., via backhaul signaling, if inter-cell signaling is present).

[0174] In the case of an implicit indication, the WTRU may determine, identify, or receive an indication (e.g., via implicit signaling, DCI, MAC-CE, or a logically equivalent message) that a potential CLI may exist or may affect the quality of the WTRU's channel and / or beam in the respective subband. In some examples, a potential interfering BS / cell may transmit a (pre-)configured signal within a window (e.g., within a time domain window and / or a frequency domain window) indicating that a change is occurring in the transmission direction. The serving BS / cell may monitor and attempt to detect the (pre-)configured signal. If the serving BS / cell detects the configured or pre-configured signal, the WTRU may receive information from the serving cell indicating a trigger or indication that a potential CLI may exist or may affect the quality of the WTRU's channel and / or beam in the respective subband.

[0175] In some cases, the WTRU may monitor and attempt to detect a (pre-)configured signal. If the WTRU detects a (pre-)configured signal, the WTRU may determine and / or identify that a potential CLI may exist or may affect the quality of the WTRU's channel and / or beam in the respective subband.

[0176] Beam failure recovery procedures are further described herein. In some embodiments, the WTRU may determine that a BFR procedure has been triggered. The WTRU may determine, identify, or configure that a potential CLI may exist or may affect the quality of the WTRU's channel and / or beam in the respective subband. The WTRU may determine and / or identify if the BFR is caused by an interfering signal (e.g., due to crosslink interference (CLI) in XDD), for example, according to one or more methods or procedures described herein. One or more of the following conditions, steps, or procedures may apply.

[0177] In some cases, if the WTRU determines that the BFD is caused due to an interfering signal (e.g., due to crosslink interference (CLI) in XDD), the WTRU may determine a second BFR parameter set (e.g., corresponding to a parameter setting due to the CLI). In some cases, the WTRU may determine, identify, or use a second candidate RS beam list from the second BFR parameter list (e.g., candidateBeamRSList_CLI). In some cases, the WTRU may start a BFR counter (e.g., BFRcounter) based on a maximum counter threshold (e.g., MaxCount_CLI) in the second BFR parameter set. In some cases, the WTRU may select a candidate RS beam from the second candidate RS beam list. In some cases, the WTRU may measure the selected candidate RS beam (e.g., SS-RSRP, CSI-RSRP, etc.). In some cases, the WTRU may compare the channel quality measurement to a quality threshold of the respective channel / beam from the second BFR parameter list (e.g., SSB-RSRP_CLI, CSI-RSRP_CLI, etc.).

[0178] In some embodiments, if the measured channel / beam parameters exceed the respective thresholds, the WTRU may measure interference based on the interference measurement reference signal and resource. In some examples, the WTRU may measure channel quality (e.g., SRS-RSRP) based on the configured SRS signal at the configured time and frequency resource. In some examples, the WTRU may measure channel quality (e.g., CLI-RSSI) based on the configured reference signal at the configured time and frequency resource.

[0179] The WTRU may compare the channel quality measurement parameters and the interference measurement parameters. In some examples, the WTRU may compare the interference measurements to the respective channel / beam interference thresholds from the second BFR parameter list (e.g., SRSrsrpThreshold_CLI, CLIrssiThreshold_CLI, etc.). In some examples, the WTRU may estimate a virtual measurement (e.g., a virtual BLER) in light of comparing the channel / beam quality measurements and the interference measurements (e.g., based on a ratio of the channel quality measurement to the interference measurement).

[0180] The WTRU may determine whether a candidate beam is a preferred beam to be selected for performing a beam recovery procedure. The WTRU may report one or more of the preferred candidate beams. The WTRU may receive information from the BS confirming the preferred beam (e.g., by receiving a PDCCH in the respective BFR CORESET or another logically equivalent message). Upon receiving the confirmation, the WTRU may begin using or be configured to begin using (e.g., switch to, update) the candidate beam for communication with the BS. Using the candidate beam for communication with the BS may include communicating with the BS based on a second spatial domain filter determined based on the candidate beam, and the candidate beam may be included in a second candidate RS beam list and confirmed by the BS based on the confirmation.

[0181] The WTRU may determine that a candidate beam is not a preferred beam. For example, a beam may not be selected as a preferred beam due to one or more of the following: a low channel quality measurement compared to a respective threshold, a high interference measurement compared to a respective threshold, a low ratio of channel quality measurement to interference measurement compared to a respective threshold, or no confirmation received from the BS on a reported preferred candidate beam (e.g., no PDCCH received via BFR CORESET or another logically equivalent message).

[0182] The WTRU may determine the next candidate beam. One or more of the following conditions, steps, or procedures may be applied or performed. For example, the WTRU may increment a BFR counter by one. The WTRU may compare the BFR counter to a maximum counter threshold (e.g., MaxCount_CLI) in the second BFR parameter set. If the BFR counter has not reached the maximum counter threshold in the second BFR parameter set, the WTRU may determine and / or select another candidate RS beam from the second candidate RS beam list. The WTRU may measure channel quality parameters and interference parameters based on the steps described above for the selected candidate beam. If the BFR counter has reached the maximum counter threshold in the second BFR parameter set, the WTRU may follow the BFR procedure for the first BFR parameter set (e.g., based on one or more steps described herein for the selected candidate beam). If the BFR counter has reached the maximum counter threshold in all BFR parameter sets, the WTRU may follow the procedure for a contention-based random access procedure.

[0183] Methods and procedures for dynamic beam failure detection and recovery are described herein.

[0184] Some embodiments for beam failure detection may describe the type of BFD identification. In some embodiments, the WTRU may determine whether the BFD is caused due to an interfering signal. For example, when operating in XDD (or dynamic / flexible TDD) mode, the WTRU may determine whether the BFD is caused due to a CLI from a potential interfering cell, a BS, or the WTRU. The WTRU may perform measurements on reference signals (e.g., SSB and / or CSI-RS) to determine the channel and / or beam quality (e.g., SS-RSRP, CSI-RSRP, SS-SINR, CSI-SINR, virtual BLER) in addition to the quality / strength of the interfering signal (e.g., CLI-RSSI, SRS-RSRP). The WTRU may compare the channel / beam measurement quality (CBMQ) to a respective channel / beam measurement threshold (CBMT). The WTRU may compare the interference measurement quality / strength (IMQ) to a respective interference measurement threshold (IMT).

[0185] In some embodiments, the WTRU may determine different types for beam failure detection based on a combination of CBMQ and IMQ results and according to respective thresholds. Thus, the WTRU may determine one or more operating modes and WTRU behavior based on the determined BFD type. One or more of the following conditions, steps, or procedures may apply.

[0186] One type of BFD can be referred to as BFD type 1. In the case of type 1 BFD, the WTRU may determine that the channel / beams quality is lower than their respective thresholds, but the interference quality / intensity is lower than the corresponding thresholds (e.g., CBMQ < CBMT and IMQ < IMT). The WTRU may accordingly determine the operating mode. For example, the WTRU may determine that the BFD may have been caused by reasons other than CLI from an interfering WTRU or BS in XDD mode. Thus, the WTRU can initiate beam failure recovery procedures (e.g., random access procedures) based on a first BFR parameter set corresponding to beam failures caused by reasons other than interference and / or CLI.

[0187] Another type of BFD can be referred to as BFD type 2. In the case of type 2 BFD, the WTRU may determine that the channel / beams quality is lower than the corresponding threshold, but the interference quality / intensity is above their respective acceptable thresholds and / or out-of-sync indication (e.g., CBMQ < CBMT and IMQ ≥ IMT). The WTRU may accordingly determine the operating mode. For example, the WTRU may determine that the BFD may have been caused by CLI from an interfering WTRU or BS in XDD mode. Thus, the WTRU can initiate beam failure recovery procedures (e.g., random access procedures) based on a second BFR parameter set corresponding to beam failures caused by interference (e.g., CLI). In some examples, if the WTRU determines that the BFD was caused by interference (e.g., CLI), the WTRU may verify or determine whether an uplink channel is available. If the WTRU determines that the uplink channel is available, the WTRU may initiate the BFD procedure accordingly (e.g., based on a BFR MAC-CE, or another logically equivalent message).

[0188] Another type of BFD may be referred to as BFD Type 3. For Type 3 BFD, the WTRU may determine that the channel / beam quality is above or equal to a respective threshold, but the interference quality / strength is above or equal to a corresponding acceptable threshold (e.g., CBMQ>CBMT and IMQ≧IMT).

[0189] In an embodiment, the WTRU may determine the operation mode accordingly. In some embodiments, the WTRU may determine that the BFD and / or partial BFD may be caused due to a CLI from an interfering WTRU or BS in XDD mode. The WTRU may therefore initiate a beam failure recovery procedure (e.g., a random access procedure) based on a second BFR parameter set corresponding to a beam failure caused by the interference (e.g., CLI). In some examples, if the WTRU determines that the BFD is due to interference (e.g., CLI), the WTRU may verify or determine whether an uplink channel is available. If the WTRU determines that an uplink channel is available, the WTRU may accordingly initiate a BFD procedure (e.g., based on a BFR MAC-CE, or another logically equivalent message). Alternatively or in addition, in some examples, the WTRU may measure, estimate, and / or determine the received power and the beam direction in which the interference (e.g., CLI) is received. The WTRU may therefore (e.g., dynamically) determine a preferred BFR RS beam accordingly. The WTRU may then further report the preferred candidate BFR RS beam. Additionally, the WTRU may further use information regarding the beam direction in which power and interference (e.g., CLI) are received. In an example, the WTRU may select, estimate, and / or determine a precoding matrix indication (PMI) in the CSI-RS report accordingly.

[0190] Methods and procedures for candidate beam RS recommendation and / or reporting are described herein. In some embodiments, the WTRU may use results from channel / beam measurements in addition to interference (e.g., CLI) measurements to dynamically recommend / report (e.g., to a serving cell / BS) preferred and / or optimal BFR parameter sets, e.g., via the MAC-CE in the UL direction. Thus, the WTRU may correlate results from channel / beam measurements with interference measurements to determine the power / strength and / or beam direction of potential interference sources (e.g., interfering cells, BSs, CLI from WTRUs in XDD mode).

[0191] In some examples, the WTRU may measure, estimate, and / or determine the beam direction of an interfering cell, BS, and / or potential interference (e.g., CLI) from the WTRU. The WTRU may then refine, update, and / or recommend (e.g., to a serving cell / BS) a candidate beam RE list that is preferably used when BFD is triggered due to the corresponding interfering signal (e.g., CLI).

[0192] In some embodiments, the WTRU may measure, estimate, and / or determine the power / strength and / or beam direction of an interfering signal to determine the best beam selection from the candidate RS beams when a BFR is caused due to an interfering signal (e.g., a CLI). Thus, the WTRU may use a combination and / or association of channel measurements and interference measurements to select the best beam during a beam recovery procedure.

[0193] Methods and procedures for beam failure recovery based on BFR MAC-CE or other logically equivalent messages are described herein. In some embodiments, the WTRU may verify and / or determine if an uplink channel is available during a beam failure recovery procedure. In some examples, during a beam failure recovery procedure, the WTRU may determine that the beam failure detection may be caused by an interfering signal (e.g., CLI in XDD (or dynamic / flexible TDD)) on a downlink channel / beam in, for example, the respective subband. Thus, the uplink channel (e.g., UL-SCH) may be available for use by the WTRU.

[0194] In some embodiments, if the WTRU determines during the channel recovery procedure that the uplink channel is available, the WTRU may generate and send a message, such as a BFR MAC-CE, to indicate beam failure detection. In one example, the message may include an indication of an index to an SSB and / or CSI-RS that has an RSRP above a threshold, or the like.

[0195] Methods and procedures for subband-based CLI detection are described herein. A WTRU may be configured to monitor, estimate, and / or measure a reference signal from a beam failure detection set (e.g., the q0 list).

[0196] In some embodiments, the WTRU may be configured with one or more subsets (e.g., settings, parameters, windows, references, etc.) of the time and / or frequency masks. In one example, the WTRU may use the time and / or frequency masks to determine one or more sets of subbands and / or time slots. Thus, the WTRU may monitor, estimate, and / or measure a reference signal from a beam failure detection set (e.g., q0 list) based on the received, configured, or determined time and / or frequency masks.

[0197] In some embodiments, the WTRU may monitor, estimate, and / or measure interference (e.g., CLI) on subbands and / or time slots determined based on a time and / or frequency mask. The WTRU may determine that the beam failure is caused by an interfering signal (e.g., CLI). In some examples, the WTRU may determine that the BFD is due to CLI if the quality / SINR of q0 over the resource mask is higher than the quality / SINR of q0 plus a configured threshold. In some examples, the serving cell may configure the time and / or frequency mask such that there is no interference (e.g., CLI) over the respective time and frequency resources.

[0198] Although the features and elements are described above in certain combinations, one skilled in the art will understand that each feature or element may be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) 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 disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A beam failure recovery (BFR) method performed by a wireless transmit / receive unit (WTRU) having multiple antenna panels, A step of receiving configuration information including multiple BFR parameter sets, wherein each BFR parameter set includes a set of candidate beam reference signals (candidate beam RS), a measurement criterion, and a crosslink interference criterion (CLI criterion), A step in initiating the beam failure recovery procedure, Determining a first BFR parameter set from a plurality of BFR parameter sets based on the priority of the first BFR parameter set, wherein the priority of the first BFR parameter set is determined based on which of the plurality of antenna panels is active or based on the received indication. Based on each set of candidate beam RS from the determined first BFR parameter set, measure CLI. It is determined that at least one candidate beam RS in the first BFR parameter set does not satisfy either the measurement criterion or the CLI criterion. Selecting from the plurality of BFR parameter sets a second BFR parameter set such that at least one candidate beam RS in the set of candidate beam RSs satisfies both the measurement criterion and the CLI criterion. Selecting a candidate beam RS that satisfies the measurement criterion and the CLI criterion within the set of candidate beam RSs of the second BFR parameter set, and The steps include transmitting an indication of the selected candidate beam RS and A method for providing this.

2. The method according to claim 1, wherein the measurement criterion is the reference signal received power (RSRP).

3. The method of claim 1 or 2, wherein the CLI criterion is based on a crosslink interference received signal strength indicator (CLI-RSSI).

4. The method according to claim 1 or 2, wherein, under the condition that a first antenna panel among the plurality of antenna panels is active, the first BFR parameter set is associated with the first antenna panel, and the priority of the first BFR parameter set is the highest priority based on the fact that the first antenna panel is active.

5. The method according to claim 1 or 2, further comprising the step of sending a message indicating the number of available antenna panels.

6. The method of claim 1 or 2, wherein each BFR parameter set further comprises at least one of a list of beams for the WTRU to monitor, a BFR counter threshold, and a set of uplink resources.

7. The method according to claim 1 or 2, wherein the WTRU operates in cross-division duplex mode or dynamic time-division duplex mode.

8. The method of claim 1 or 2, further comprising the step of receiving confirmation of the selected candidate beam RS.

9. The method according to claim 1 or 2, further comprising the steps of: determining that the WTRU has not received confirmation of the selected candidate beam; selecting a second candidate beam RS; and transmitting an indication indicating the selected second candidate beam RS.

10. A wireless transmit / receive unit (WTRU), Multiple antenna panels, The system receives configuration information including multiple beam failure recovery parameter sets (multiple BFR parameter sets), each BFR parameter set including a set of candidate beam reference signals (candidate beam RS), a measurement criterion, and a crosslink interference criterion (CLI criterion). Based on the priority of the first BFR parameter set, the first BFR parameter set is determined from the plurality of BFR parameter sets, and the priority of the first BFR parameter set is determined based on which of the plurality of antenna panels is active or based on the received indication. Based on each set of candidate beam RS from the determined first BFR parameter set, the CLI is measured, Under the condition that at least one candidate beam RS in the first BFR parameter set does not satisfy either the measurement criterion or the CLI criterion, From the plurality of BFR parameter sets, select a second BFR parameter set such that at least one candidate beam RS in the set of candidate beam RS satisfies both the measurement criterion and the CLI criterion. Within the set of candidate beam RSs of the second BFR parameter set, select a candidate beam RS that satisfies the measurement criterion and the CLI criterion. Transmit an indication showing the selected candidate beam RS. A circuit configured in such a way WTRU equipped with.

11. The WTRU according to claim 10, wherein the measurement criterion is the reference signal received power (RSRP).

12. The WTRU of claim 10 or 11, wherein the CLI criterion is based on a cross-link interference received signal strength indicator (CLI-RSSI).

13. The WTRU of claim 10 or 11, provided that a first antenna panel among the plurality of antenna panels is active, the first BFR parameter set is associated with the first antenna panel, and the priority of the first BFR parameter set is the highest priority based on the first antenna panel being active.

14. A WTRU according to claim 10 or 11, further configured to transmit a message indicating the number of available antenna panels.

15. The WTRU of claim 10 or 11, wherein each BFR parameter set further comprises at least one of a list of beams for the WTRU to monitor, a BFR counter threshold, and a set of uplink resources.

16. The WTRU according to claim 10 or 11, wherein the WTRU is configured to operate in cross-division dual communication mode or dynamic time-division dual communication mode.

17. The WTRU of claim 10 or 11, further configured to receive confirmation of the selected candidate beam RS.

18. A WTRU according to claim 10 or 11, further configured to select a second candidate beam RS and transmit an indication indicating the selected second candidate beam RS, provided that the WTRU does not receive confirmation of the selected candidate beam.

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