Method for beam fault detection and recovery

Abstract

Methods and apparatus for beam fault detection and recovery (BFR) are described. The method includes a wireless transmit / receive unit: receiving configuration information including a set of BFR parameters having corresponding candidate beam reference signals (RS), measurement criteria, and interference criteria; detecting a beam fault; determining a first set of BFR parameters based on a priority of the first set of BFR parameters, wherein the priority of the first set of BFR parameters is determined based on which of the plurality of antenna panels is active or based on the received indication; under the condition that at least one candidate beam RS of a set of candidate beam RSs of the first set of BFR parameters satisfies both the measurement criterion and the interference criterion: selecting a candidate beam RS of the set of candidate beam RSs of the first set of BFR parameters that satisfies the measurement criterion and the interference criterion, and indicating the selected candidate beam RS.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 332,180, filed on April 18, 2022, the contents of which are incorporated herein by reference. Background Art

[0003] The 3rd Generation Partnership Project (3GPP) New Radio (NR) for wireless communications provides duplex operation to be implemented. Such technology can provide a basis for improvement of conventional time division duplex (TDD) operation, for example, by enhancing uplink (UL) coverage, improving capacity and reducing latency. Conventional TDD can be implemented, for example, by dividing the time domain between uplink and downlink. The feasibility of allowing full duplex at the base station (BS) side within the conventional TDD band, or more specifically, allowing cross-division duplex (XDD) as sub-band non-overlapping full duplex, is being explored. Summary of the invention

[0004] A method and apparatus for beam failure detection and recovery is provided herein. A method for beam failure detection performed by a wireless transmit receive unit (WTRU) may include: receiving configuration information including multiple beam failure recovery (BFR) parameter sets, wherein each BFR parameter set includes a corresponding set of candidate beam reference signals (RS), measurement (RSRP) criteria, and interference (CLI) criteria; detecting a beam failure; determining a first BFR parameter set from the multiple BFR parameter sets based on a priority of the first BFR parameter set, wherein the priority of the first BFR parameter set is determined based on which panel is active or based on a received indication; and under the condition that at least one candidate beam RS in the set of candidate beam RSs in the first BFR parameter set meets both the measurement and interference criteria: selecting a candidate beam RS in the set of candidate beam RSs in the first BFR parameter set that meets the measurement and interference criteria, and transmitting an indication indicating the selected candidate beam RS. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A more detailed understanding may be obtained from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals indicate like elements, and in which:

[0006] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0007] Figure 1B is an example of an embodiment in which Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within the illustrated communication system;

[0008] Figure 1C is an example of an embodiment in which Figure 1A a system diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within the illustrated communication system;

[0009] Figure 1D is an example of an embodiment in which Figure 1A A system diagram of another example RAN and another example CN used within the illustrated communication system;

[0010] Figure 2 is a diagram illustrating cross-division duplexing;

[0011] Figure 3 is a diagram illustrating the CLI between a gNB and a WTRU;

[0012] Figure 3 is a diagram illustrating a panel switching mechanism in beam failure recovery caused by CLI in Cross Division Duplex (XDD) (or dynamic / flexible TDD scheme);

[0013] Figure 4A is a diagram illustrating an example of beam selection between a base station and a WTRU;

[0014] Figure 4B is a diagram illustrating an example of a CLI between a base station and a WTRU;

[0015] Figure 4C is a diagram illustrating an example of a CLI between a base station and a WTRU;

[0016] Figure 5 is a diagram illustrating an example process;

[0017] Figure 6 is a diagram illustrating an example process; and

[0018] Figure 7 is a diagram illustrating an example process. DETAILED DESCRIPTION

[0019] Figure 1A1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word discrete Fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0020] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d 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 send and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, 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 process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0021] The communication 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 communication 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 evolved Node B (eNB), a Home Node B, a Home evolved Node B, a next generation Node B such as a gNode B (gNB), a new radio (NR) Node B, a site controller, an access point (AP), a wireless router, and the like. While 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.

[0022] The base station 114a may be part of the RAN 104, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an 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, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0023] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over 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).

[0024] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), that may use Wideband CDMA (WCDMA) to establish the air interface 116. WCDMA may include communication 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).

[0025] In an 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) that may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0026] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology (such as NR radio access) that may establish the air interface 116 using NR.

[0027] In an 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 together implement LTE radio access and NR radio access, for example using the dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0028] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies 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), etc.

[0029] Figure 1A The base station 114b in the 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 local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. 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 an 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 utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, the base station 114 b may have a direct connection to the Internet 110. Therefore, the base station 114 b may not need to access the Internet 110 via the CN 106.

[0030] The RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 may provide call control, billing 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 described in detail in the accompanying drawings, the CN 106 may be configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Figure 1AAlthough not shown in the figure, it will be appreciated that the RAN 104 and / or the CN 106 may be in direct or indirect communication with other RANs that employ 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 be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0031] The CN 106 may also act 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 that provides 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) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks 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 employ the same RAT as the RAN 104 or a different RAT.

[0032] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication 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 via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0033] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, 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 appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0034] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of 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 decoding, 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 Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0035] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from the base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0036] Although the transmit / receive element 122 Figure 1B 1 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.

[0037] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0038] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) 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 a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a 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, or the like. 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 a home computer (not shown).

[0039] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0040] The processor 118 may also be coupled to the 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 the 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 received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0041] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules 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 video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device, activity tracker, etc. The peripheral device 138 may include one or more sensors. The sensor may be one or more of the following: 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, etc.

[0042] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and DL (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via signal processing performed by hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with specific subframes for both UL (e.g., for transmission) or DL ​​(e.g., for reception)) may be concurrent and / or simultaneous.

[0043] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0044] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0045] Each of the evolved Node Bs 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 UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0046] Figure 1C The illustrated CN 106 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 should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0047] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an 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.

[0048] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0049] The SGW 164 may be connected to the 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.

[0050] 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 may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts 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 networks and / or wireless networks owned and / or operated by other service providers.

[0051] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communication interface with a communication network.

[0052] In a representative embodiment, the other network 112 may be a WLAN.

[0053] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and leading to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and leading to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Direct link establishment (DLS) may be utilized to transmit point-to-point traffic 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 tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0054] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send beacons 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 set width. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (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.

[0055] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0056] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be sent by the transmitter STA. At the receiver of the receiver STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0057] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0058] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. 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 set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (which only supports a 1MHz operating mode) is transmitting to the AP, all available bands may be considered busy even if most of the available bands remain idle.

[0059] In the United States, the available frequency band for 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 code.

[0060] Figure 1D1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0061] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated 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 one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an 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 an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNB 180a and the gNB 180b (and / or the gNB 180c).

[0062] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with a set of parameters that may be scalable. For example, 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 transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths over time).

[0063] 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 while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRU 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the evolved Node-B 160a, 160b, 160c. For example, the WTRU 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the evolved Node-B 160a, 160b, 160c may act as a mobility anchor for the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRU 102a, 102b, 102c.

[0064] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, interworking between DC, NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0065] Figure 1DThe illustrated CN 106 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although the aforementioned elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0066] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 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.

[0067] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 106 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 106 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure the traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy implementation and QoS, providing DL data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0068] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the 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 UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, etc.

[0069] The CN 106 may facilitate communications with other networks. For example, the CN 106 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts 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 networks 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 DNs 185a, 185b via the UPFs 184a, 184b via the N3 interfaces to the UPFs 184a, 184b and the N6 interfaces between the UPFs 184a, 184b and the local DNs 185a, 185b.

[0070] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following items may be performed by one or more simulation devices (not shown): WTRU102a to 102d, base station 114a to 114b, evolved Node B 160a to 160c, MME 162, SGW 164, PGW 166, gNB180a to 180c, AMF 182a to 182b, UPF 184a to 184b, SMF 183a to 183b, DN 185a to 185b and / or any other device described herein. The simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, the simulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0071] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for the purpose of testing and / or performing tests using over-the-air wireless communications.

[0072] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0073] The acronyms and abbreviations used in the preceding and following paragraphs may be defined as follows:

[0074] Δf Subcarrier spacing

[0075] gNB NR Node B

[0076] AP Aperiodic

[0077] BFR Beam Failure Recovery

[0078] BFD-RS Beam Fault Detection Reference Signal

[0079] BLER Block Error Rate

[0080] BWP Bandwidth Part

[0081] CA Carrier Aggregation

[0082] CB Contention-based (e.g., access, channel, resources)

[0083] CCA Clear Channel Assessment

[0084] CDM Code Division Multiplexing

[0085] CG Cell Group

[0086] CLI Cross Link Interference

[0087] CoMP Coordinated Multi-Point Transmission / Reception

[0088] COT Channel Occupancy Time

[0089] CP Cyclic Prefix

[0090] CPE Common Phase Error

[0091] CP-OFDM Conventional OFDM (depends on cyclic prefix)

[0092] CQI Channel Quality Indicator

[0093] CN Core Network (e.g., LTE Packet Core or NR Core)

[0094] CRC Cyclic Redundancy Check

[0095] CSI Channel State Information

[0096] CSI-RS Channel State Information Reference Signal

[0097] CU Central Unit

[0098] D2D device-to-device transmission (e.g., LTE sidelink)

[0099] DC Dual Connectivity

[0100] DCI Downlink Control Information

[0101] DL Downlink

[0102] DM-RS Demodulation Reference Signal

[0103] DRB Data Radio Bearer

[0104] DU Distributed Unit

[0105] EN-DC E-UTRA-NR dual connectivity

[0106] EPC Evolved Packet Core

[0107] FD-CDM Frequency Domain Code Division Multiplexing

[0108] FDD Frequency Division Duplex

[0109] FDM Frequency Division Multiplexing

[0110] ICI Inter-cell Interference

[0111] ICIC Inter-cell Interference Cancellation

[0112] IP Internet Protocol

[0113] LBT Listen before you speak

[0114] LCH Logical Channel

[0115] LCID Logical Channel Identifier

[0116] LCP Logical Channel Priority

[0117] LLC low latency communication

[0118] LTE Long Term Evolution, such as from 3GPP LTE Release 8 and higher

[0119] MAC Media Access Control

[0120] MAC CE Medium Access Control Element

[0121] NACK Negative ACK

[0122] MBMS Multimedia Broadcast Multicast System

[0123] MCG Master Cell Group

[0124] MCS modulation and coding scheme

[0125] MIMO Multiple Input Multiple Output

[0126] MTC Machine Type Communication

[0127] MR-DC Multi-RAT Dual Connectivity

[0128] NAS Non-Access Stratum

[0129] NCB-RS New Candidate Beam Reference Signal

[0130] NE-DC NR-RAN–E-UTRA Dual Connectivity

[0131] NR New Radio

[0132] NR-DC has dual connectivity

[0133] OFDM Orthogonal Frequency Division Multiplexing

[0134] OOB Out of Band (Emit)

[0135] P cmax Total available WTRU power in a given transmission interval

[0136] Pcell Primary cell of the primary cell group

[0137] PCG Primary Cell Group

[0138] PDU Protocol Data Unit

[0139] PER Packet Error Rate

[0140] PHY Physical Layer

[0141] PLMN Public Land Mobile Network

[0142] PLR Packet Loss Rate

[0143] PRACH Physical Random Access Channel

[0144] PRB Physical Resource Block

[0145] PRS Positioning Reference Signal

[0146] Pscell: the primary cell of the secondary cell group

[0147] PSS Primary Synchronization Signal

[0148] PT-RS Phase Tracking Reference Signal

[0149] QoS Quality of Service (from the perspective of the physical layer)

[0150] RAB Radio Access Bearer

[0151] RAN PA Radio Access Network Paging Area

[0152] RACH Random Access Channel (or process)

[0153] RAR Random Access Response

[0154] RAT Radio Access Technology

[0155] RB Resource Block

[0156] RCU Radio Access Network Central Unit

[0157] RF Radio Front End

[0158] RE Resource Element

[0159] RLF Radio Link Failure

[0160] RLM Radio Link Monitoring

[0161] RNTI Radio Network Identifier

[0162] RO Random Access Opportunity

[0163] ROM read-only mode (for MBMS)

[0164] RRC Radio Resource Control

[0165] RRM Radio Resource Management

[0166] RS reference signal

[0167] RTT Round Trip Time

[0168] SCG Secondary Cell Group

[0169] SCMA Single Carrier Multiple Access

[0170] SCS Subcarrier Spacing

[0171] SDU Service Data Unit

[0172] SOM Spectrum Operation Mode

[0173] SP Semi-Persistent

[0174] SpCell Primary cell of primary cell group or secondary cell group

[0175] SRB Signalling Radio Bearer

[0176] SS Sync Signal

[0177] SRS Sounding Reference Signal

[0178] SSS Secondary synchronization signal

[0179] SUL Supplementary Uplink

[0180] SWG Switching Gap (in an independent subframe)

[0181] TB Transfer Block

[0182] TBS Transport Block Size

[0183] TCI Send Configuration Index

[0184] TDD Time Division Duplex

[0185] TDM Time Division Multiplexing

[0186] TI time interval (in units of integer multiples of one or more symbols)

[0187] TTI Transmit Time Interval (in units of one or more integer multiples of symbols)

[0188] TRP Send / Receive Point

[0189] TRPG send / receive point group

[0190] TRS Tracking Reference Signal

[0191] TRx Transceiver

[0192] UL Uplink

[0193] URC Ultra Reliable Communications

[0194] URLLC Ultra-Reliable Low Latency Communications

[0195] V2X vehicle-to-vehicle communications

[0196] WLAN Wireless Local Area Network and related technologies (IEEE 802.xx domain)

[0197] XDD Cross Division Duplex

[0198] The terms further defined herein may be referred to using a variety of different symbols. Hereinafter, "a", "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". For example, the term "may" may be interpreted as "can".

[0199] A beam may be defined as follows: A WTRU may transmit or receive a physical channel transmit or reference signal according to at least one spatial domain filter. The term "beam" may be used to refer to a spatial domain filter.

[0200] The WTRU may transmit a physical channel transmission or signal using the same spatial domain filters as used to receive RS (such as CSI-RS) or SS blocks. 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 cases, the WTRU may be said to transmit the target physical channel or signal based on the spatial relationship of the reference to such RS or SS block.

[0201] The WTRU may transmit a first physical channel transmission and / or signal according to the same spatial domain filter as used to transmit a second physical channel transmission or signal. The first transmission and the second transmission may be referred to as a "target" and a "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 with reference to a second (reference) physical channel or signal.

[0202] The spatial relationship may be implicit, configured by RRC, or signaled by MAC CE or DCI, or another logically equivalent message. For example, the WTRU may implicitly send a PUSCH transmission and a DM-RS for the PUSCH according to the same spatial domain filter as the SRS indicated by the SRI (which may be indicated in the DCI or configured by RRC or other logically equivalent message or transmission). In some examples, the spatial relationship may be configured by RRC for SRS Resource Indicator (SRI) or by MAC CE signaling for PUCCH, or by other logically equivalent means. Such a spatial relationship may also be referred to as "beam indication".

[0203] 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 corresponding DM-RS. Such an association may exist at least when the first signal and the second signal are reference signals and when the WTRU is configured with a quasi co-location (QCL) assumption type D between the corresponding antenna ports. Such an association may be configured as a TCI (transmission configuration indicator) state. The WTRU may indicate the association between a CSI-RS or SS block and a DM-RS by an index to a TCI state set (configured by the RRC and / or signaled by the MACCE). Such an indication may also be referred to as a "beam indication".

[0204] The terms related to TRP in this document may be used as follows. In the following, TRP (e.g., transmit receive point) may be used interchangeably with one or more of TP (transmit point), RP (receive point), RRH (radio remote head), DA (distributed antenna), BS (base station), (BS's) sector and / or cell (e.g., the geographic cell area served by the BS), but still consistent with the description provided herein. In the following, the term multi-TRP may be used interchangeably with one or more of MTRP, M-TRP, and multiple TRPs, but still consistent with the description provided herein.

[0205] In the following, the term "beam" may be used to refer to the antenna panel.

[0206] In the following, the term "subband" is used to refer to frequency domain resources and may be characterized by at least one of: a set of resource blocks (RBs); a set of resource block sets (RB sets) (e.g., when a carrier has an intra-cell guard band); a set of interleaved resource blocks; a bandwidth portion or a portion thereof; or a carrier or a portion thereof. For example, a subband may be characterized by a starting RB and a number of RBs of a set of consecutive RBs within a bandwidth portion. A subband may also be defined by a value of a frequency domain resource allocation field and a bandwidth portion index.

[0207] In the following, the term "XDD" may be used to refer to a sub-band-wise duplexing scheme (e.g., UL or DL ​​is used per sub-band), and may be characterized by at least one of: a cross-division duplexing (e.g., sub-band-wise FDD within a TDD band) scheme; a sub-band-based full-duplexing scheme (e.g., full-duplexing because both UL and DL are used / mixed on a symbol / time slot, and UL or DL ​​is used per sub-band on a symbol / time slot); a frequency domain multiplexing (FDM) scheme for DL / UL transmission within a TDD spectrum; a sub-band non-overlapping full-duplexing scheme (e.g., non-overlapping sub-band full-duplexing); full-duplexing other than a co-frequency (e.g., spectrum sharing, sub-band-wise overlapping) full-duplexing scheme; or an advanced duplexing method, e.g., other than (pure) TDD or FDD.

[0208] Hereinafter, the term "dynamic ( / flexible) TDD" may be used to refer to a TDD system / cell that can dynamically (and / or flexibly) change / adjust / switch a communication direction (e.g., downlink, uplink, or sidelink, etc.) based on a time instance (e.g., time slot, symbol, subframe, etc.). In one example, in a system adopting dynamic / flexible TDD, based on an indication of a group common (GC)-DCI (e.g., format 2_0) including a time slot format indicator (SFI) and / or based on a tdd-UL-DL-config-common / dedicated configuration, a component carrier (CC) or a bandwidth part (BWP) may have a single type of 'D', 'U', and 'F' on a symbol / time slot. At a given time instance / time slot / symbol, a first BS (e.g., cell, TRP) employing dynamic / flexible TDD may send a downlink signal to a first WTRU communicating / associated with the first BS based on a first SFI and / or tdd-UL-DL-config configured / indicated by the first BS, and a second BS (e.g., cell, TRP) employing dynamic / flexible TDD may receive an uplink signal sent from a second WTRU communicating / associated with the second BS based on a second SFI and / or tdd-UL-DL-config configured / indicated by the second BS. In some examples, the first WTRU may determine that reception of the downlink signal is being interfered with by the uplink signal, where the interference caused by the uplink signal may refer to WTRU-to-WTRU cross-link interference (CLI).

[0209] The WTRU may report a subset of channel state information (CSI) components, where the CSI components may correspond to at least a CSI-RS resource indicator (CRI), an SSB resource indicator (SSBRI), an indication of a panel for reception at the WTRU (such as a panel identifier or a group identifier), measurement results such as L1-RSRP, L1-SINR obtained from SSB or CSI-RS (e.g., cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR), and at least other channel state information such as a rank indicator (RI), a channel quality indicator (CQI), a precoding matrix indicator (PMI) and / or a layer index (LI).

[0210] 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 for each BWP for monitoring and detecting beam failure detection. For example, the term q0 may be used for a beam failure detection set. In another example, the term q0,0 or q0,1 may be used as a beam failure detection set. A beam failure detection set (e.g., set q0, q0,0 or q0,1) may include one or more reference signals, where the reference signal may be a CSI-RS resource configuration index and / or a SS / PBCH block (SSB) index. 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).

[0211] If the WTRU is not provided / configured with a beam failure detection RS set for BWP (e.g., set q0, q0,0, or q0,1), the WTRU may determine the corresponding RS set. For example, the WTRU may determine the RS signals to be included in the beam failure detection RS set for BWP based on the periodic CSI-RS resource configuration index that the WTRU uses to monitor the PDCCH transmission in the corresponding CORESET as indicated by the TCI state.

[0212] The WTRU may measure the 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 corresponding beam. The terms Q_out and Q_in may be used to represent one or more attributes and parameters and corresponding values.

[0213] The threshold Q_out may be used to determine a radio link and / or beam quality at which signal transmission may not be reliably received, corresponding to, for example, an out-of-sync block error rate (BLER_out). Alternatively or additionally, the threshold Q_in may be used to determine a radio link and / or beam quality at which signal transmission can be reliably received, corresponding to a in-sync block error rate (BLER_in). BLER_out and / or BLER_in may be explicitly determined by the BS.

[0214] In the case where the BS does not explicitly determine BLER_out and / or BLER_in, 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 assessment and / or in-sync assessment. In some examples, the number of OFDM symbols, aggregation level, ratio of assumed PDCCH RE energy to average SSS RE energy, ratio of assumed 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.

[0215] 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 in evaluating the out-of-sync threshold and the in-sync threshold. One or more of these parameters may be included. The values, number of PRBs, and selections for each parameter are examples. Other values, number of PRBs, or selections may be included.

[0216] property Value of BLER configuration #0 DCI format 1-0 Controlling the number of OFDM symbols 2 Aggregation Level (CCE) 8 Ratio of assumed PDCCH RE energy to average SSS RE energy 4dB Ratio of assumed PDCCH DMRS energy to average SSS RE energy 4dB Bandwidth (PRB) 24 Subcarrier spacing (kHz) SCS of active DL BWP DMRS pre-decoder granularity REG Bundle Size REG Bundle Size 6 CP length normal Mapping from REG to CCE distributed

[0217] Table 1

[0218] property Value of BLER configuration #0 DCI payload size 1-0 Controlling the number of OFDM symbols 2 Aggregation Level (CCE) 4 Ratio of assumed PDCCH RE energy to average SSS RE energy 0dB Ratio of assumed PDCCH DMRS energy to average SSS RE energy 0dB Bandwidth (PRB) 24 Subcarrier spacing (kHz) SCS of active DL BWP DMRS pre-decoder granularity REG Bundle Size REG Bundle Size 6 CP length normal Mapping from REG to CCE distributed

[0219] Table 2

[0220] Various aspects of beam failure detection are described herein. The WTRU may monitor a beam failure detection RS set in an active BWP. The WTRU may also estimate the beam / radio link quality and report an out-of-sync state and / or an in-sync state. In one example, the WTRU may measure the radio link quality (L1-RSRP) of the SSB and / or CSI-RS in the corresponding beam failure detection RS set. The WTRU may then compare the measurement results with corresponding thresholds to determine, indicate, or detect whether a beam failure instance (BFI) has occurred.

[0221] The WTRU may indicate, determine or be configured with one or more beam failure detection (BFD) counters. In this way, 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 for counting the number of BFIs, which may be initially set to 0 and incremented at each BFI detection; BFI_Max_Count, which may be the maximum value of the BFI_Counter that may trigger beam failure detection; or BFD_Timer, which may be a timer that starts with the first BFI detection. Alternatively or additionally, the parameter BFD_Timer may refer to a time period that is considered when determining whether a beam failure has occurred. For example, the BFD_Timer may define a duration during which the WTRU monitors for the occurrence of one or more conditions. If the timer or time period expires before the BFI_Counter reaches the BFI_Max_Count, the beam failure detection process is stopped.

[0222] 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 be included.

[0223] In some examples, if a BFI has occurred, the WTRU may start and / or restart the BFD_timer (i.e., monitor one or more conditions for a given duration) and increment the BFI_counter by 1. If the BFI_counter reaches the 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 has expired and the BFI_counter has not reached the BFI_Max_count.

[0224] Other aspects of beam failure recovery are described herein. The WTRU may determine, indicate, or trigger beam failure recovery based on a beam failure detection process. The WTRU may indicate, determine, or be configured with one or more of the following parameters: a BFR_timer, which may represent a duration starting with a beam failure recovery process; an RSRP_threshold, which may be a threshold for RSRP used in beam failure recovery, a candidateBeamRSList, which may provide a list of candidate beam reference signal indices to be monitored, measured, and selected during beam failure recovery; a power ramp parameter, which may include a power ramp step, a received preamble target power, or other; or a random access parameter, which may include a PRACH parameter, which includes a preamble index, an SSB per RACH opportunity, a random access response window, a PRACH configuration index, a random access opportunity, and an SSB association mask index, among others.

[0225] The WTRU may use / receive / or be configured with one or more sets of reference signals for each BWP for monitoring, measurement, and selection as resources for beam failure recovery. For example, the term q1 may be used for a beam failure recovery set. As another example, the terms q1,0 or q1,1 may be used as a 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, where the reference signal 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 a candidateBeamRSList that is configured as part of the BFR process.

[0226] The WTRU may initiate beam failure recovery based on a random access procedure. In some examples, the WTRU may configure random access parameters, start monitoring one or more conditions during a duration defined by parameters such as BFR_timer, and apply power ramp parameters. The WTRU may monitor and measure one or more reference signals from the reference signals in candidateBeamRSList. The WTRU may determine whether at least one of the SSBs has an SS-RSRP higher than the corresponding RSRP_threshold in the SSBs in candidateBeamRSList, or whether at least one of the CSI-RSs has a CSI-RSRP higher than the corresponding RSRP_threshold in the CSI-RS in candidateBeamRSList. The WTRU may then select the corresponding reference signal as a candidate new beam / random access resource for the BFR procedure. For example, the term q_new may be used to represent a newly selected beam / random access resource. In the corresponding random access resource, and based on the spatial relationship of the SS / PBCH blocks associated with the periodic CSI-RS resource configuration or the index q_new, the WTRU may perform a PRACH transmission.

[0227] 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. In this case, the WTRU may generate a BFR MAC-CE or equivalent message and send the message using the corresponding uplink channel resources.

[0228] The WTRU may determine, identify or be configured with one or more CORESETs corresponding to the random access procedure for corresponding beam failure recovery. In one example, the WTRU may monitor the PDCCH transmission in the search space set to detect a DCI format with a corresponding CRC scrambled with a radio network identifier (e.g., C-RNTI or MCS-C-RNTI). The WTRU may determine the same antenna port quasi-co-location parameters as the antenna port quasi-co-location parameters associated with index q_new for monitoring the PDCCH in the search space set and receiving the corresponding PDSCH transmission.

[0229] If the duration provided, for example, by the parameter BFR_Timer has expired and the beam failure recovery procedure has not been successfully completed, the WTRU may trigger a link failure detection and follow a link failure recovery (LFR) procedure.

[0230] Channel and / or interference measurements are described herein. A WTRU may receive a synchronization signal / physical broadcast channel (SS / PBCH) block. An SS / PBCH block (SSB) may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and / or a physical broadcast channel (PBCH). A WTRU may monitor, receive, or attempt to decode an SSB during initial access, initial synchronization, radio link monitoring (RLM), cell search, cell handover, etc.

[0231] The WTRU may measure and report channel state information (CSI), wherein the CSI for each connection mode may include or be configured with one or more of the following parameters. For example, the WTRU may be configured with a CSI reporting configuration that may include one or more of the following: CSI reporting amount, such as channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), CSI-RS resource indicator (CRI), layer indicator (LI), etc.; CSI reporting type, such as aperiodic, semi-persistent, periodic; CSI reporting codebook configuration, such as type I, type II, type II port selection, etc.; or CSI reporting frequency.

[0232] The WTRU may be configured with a CSI-RS resource set including one or more of the following CSI resource settings: NZP-CSI-RS resources for channel measurement; NZP CSI-RS resources for interference measurement; or CSI-IM resources for interference measurement.

[0233] The WTRU may be configured with NZP-CSI-RS resources including one or more of: 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.

[0234] 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 the corresponding reference signals. For example, one or more of the following may be applied. The following parameters are non-limiting examples of parameters that may be included in the reference signal measurement. One or more of these parameters may be included. Other parameters may be included.

[0235] 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) or SSS in PBCH). It may be defined as the linear average of the power contribution of the resource elements (REs) carrying the corresponding synchronization signal. When measuring RSRP, power scaling of the reference signal may be required. In the case where SS-RSRP is used for L1-RSRP, the measurement may be done based on the CSI reference signal in addition to the synchronization signal.

[0236] Reference signal measurements may include CSI-RSRP. CSI-RSRP may be measured based on a linear average of the power contributions of resource elements (REs) carrying corresponding CSI-RS. CSI-RSRP measurements may be configured within the measurement resources of a configured CSI-RS opportunity.

[0237] Reference signal measurements may include SS-SINR. SS signal-to-noise and interference ratio (SS-SINR) may be measured based on synchronization signals (e.g., DMRS or SSS in PBCH). It may be defined as the linear average of the power contribution of the resource elements (REs) carrying the corresponding synchronization signal divided by the linear average of the noise and interference power contributions. In the case where SS-SINR is used for L1-SINR, noise and interference power measurements may be done based on resources configured by higher layers.

[0238] Reference signal measurements may include CSI-SINR. CSI-SINR may be measured based on the linear average of the power contribution of the resource elements (REs) carrying the corresponding CSI-RS divided by the linear average of the noise and interference power contributions. In the case where CSI-SINR is used for L1-SINR, noise and interference power measurements may be done based on resources configured by higher layers. Otherwise, noise and interference power may be measured based on resources carrying the corresponding CSI-RS.

[0239] Reference signal measurements may include RSSI. A received signal strength indicator (RSSI) may be measured based on an average of total power contributions in the configured OFDM symbol and bandwidth. Power contributions may be received from different resources (e.g., co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.).

[0240] Reference signal measurements may include CLI-RSSI. A cross-link interference received signal strength indicator (CLI-RSSI) may be measured based on the average of the total power contribution in the configured OFDM symbols of the configured time and frequency resources. Power contributions may be received from different resources (e.g., cross-link interference, co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.).

[0241] Reference signal measurements may include SRS-RSRP. Sounding Reference Signal RSRP (SRS-RSRP) may be measured based on a linear average of the power contributions of the Resource Elements (REs) carrying the corresponding SRS.

[0242] As described herein, the characteristics of a grant or assignment may include at least one of: frequency allocation; aspects of time allocation, such as duration; priority; modulation and coding scheme; transport block size; number of spatial layers; number of transport blocks; TCI state, CRI, or SRI; number of repetitions; whether the repetition scheme is Type A or Type B; whether the grant is a configured grant Type 1, Type 2, or a dynamic grant; whether the assignment is a dynamic assignment or a semi-persistent scheduled (configured) assignment; a configured grant index or a semi-persistent assignment index; the periodicity of the configured grant or assignment; a channel access priority class (CAPC); and / or any parameters for scheduling grants or assignments provided in the DCI, by the MAC, or by the RRC (or by logically equivalent signaling).

[0243] As described herein, the DCI indication may consist of at least one of: an explicit indication of a DCI field or an RNTI for masking the CRC of the PDCCH; and / or an implicit indication of characteristics such as the DCI format, the DCI size, the CORESET or search space, the aggregation level, the index of the first resource element of the received DCI (e.g., the index of the first control channel element), where the mapping between the characteristics and the values ​​may be signaled by RRC or MAC or a logically equivalent message.

[0244] The term RS may be used interchangeably with one or more of an RS resource, an RS resource set, an RS port, and / or an RS port group. RS may be used interchangeably with one or more of an SSB, a CSI-RS, an SRS, and a DM-RS.

[0245] Further context for the embodiments presented herein is described below. Cross-division duplexing (XDD) can be implemented within a conventional TDD frequency band, such as Figure 2 Such a specific implementation of XDD can be subjected to addressing the key challenges caused by cross-link interference (CLI). Figure 3, in an XDD (or dynamic / flexible TDD) framework, a potential aggressor cell 310 may switch from UL to DL, or vice versa, in communication 313 with a WTRU 322, causing CLI 311 on the potential victim BS 320 and potential CLI 312 on the WTRU 330 to interfere with the communication 323 between the victim WTRU 322 and the gNB 320. In the case of UL to DL CLI, the CLI 331 from the aggressor WTRU 330 may cause beam failure detection at the victim WTRU 322. As such, the beam failure detection and recovery process including candidate RS beams may need to be selected and performed in a different manner than in conventional BFR, since the impact of interference caused by CLI is different from legacy beam detection and recovery. This may result in different WTRU behavior in the case where the beam failure is caused by CLI in XDD (or dynamic / flexible TDD).

[0246] Figures 4a to 4c illustrate examples of beam selection in the presence of CLI. In Figure 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. Figure 4B The CLI 430 shows Figure 4A The influence of beam arrangement. Figure 4C shows that in the presence of interference such as Figure 4A and Figure 4B Example beam selection in the case of CLI 430 for WTRU beams 411, 413, and 412 is shown. Figure 4C As shown, the WTRU selects beam 415 and the base station selects beam 421, even though this is the least preferred combination without the CLI. In this example, the selected beams 421, 415 work because they are reflected by object 440.

[0247] The following paragraphs provide an overview of at least several exemplary embodiments that are described in further detail.

[0248] At least one embodiment may include a panel switching mechanism in BFR caused by CLI in XDD (or dynamic / flexible TDD). Figure 5. In such an embodiment, at 510, the WTRU may report a WTRU capability value (set), which may include the number of panels (e.g., two panels). At 512, the WTRU may receive configuration information for BFR, including a list of candidate RS beams (e.g., candidateBeamRSList), a list of monitoring 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 the candidate RS beams based on priority (e.g., based on panel ID)).

[0249] The WTRU may monitor the beams in the monitoring list, and if a beam failure is detected more than a threshold number of times, the WTRU may determine whether the BFD is due to CLI, as indicated by decision point 518. If the BFD is due to CLI, one or more of the following may be applied: at 520, the WTRU may select a first BFR parameter set based on a priority (e.g., based on an active panel); at 522, the WTRU may initiate a first BFR counter (e.g., BFRcounter#1); and / or at 524, the WTRU may measure SRS-RSRP and / or CLI-RSSI based on the candidate RS beam selected in the first candidate RS beam list (e.g., candidateBeamRSList#1), and compare with a first threshold (e.g., SRSrsrpThreshold#1 and / or CLIrssiThreshold#1) at 526. If the measured resources are below the corresponding threshold, then at 528, the WTRU may send a message indicating a beam failure recovery request (BFRR) (e.g., a PRACH transmission) using the selected candidate RS beam, and then monitor the PDCCH transmission in the BFR-CORESET at 530 and establish a corresponding new beam pair link at 534. Otherwise, at 542, if the first BFR counter (e.g., BFRcounter#1) does not reach the first maximum counter threshold (e.g., MaxCount#1), then at 540, the WTRU selects another candidate RS beam from the first list (e.g., candidateBeamRSList#1).

[0250] At 542, if the first BFR counter (e.g., BFRcounter#1) has reached a first maximum counter threshold (e.g., MaxCount#1), then at 550, the WTRU may switch to a second BFR parameter set at 540. One or more of the following conditions, steps, or processes may be taken: The WTRU may reset the BFR counter, or initiate a second BFR counter (e.g., BFRcounter#2) at 552. At 524, the WTRU may measure SRS-RSRP and / or CLI-RSSI based on the 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).

[0251] If the resources measured at 526 are below the corresponding threshold, then at 528, the WTRU may use the selected candidate RS beam to send a message indicating a beam failure recovery request (BFRR) (e.g., a PRACH transmission), and then monitor the PDCCH transmission in the BFR-CORESET at 530 and establish a corresponding new beam pair link.

[0252] Otherwise, if the second BFR counter (e.g., BFRcounter#2) has not reached the 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 the corresponding maximum counter thresholds, then at 546 the WTRU may switch to a contention-based random access procedure.

[0253] References in this article Figure 6 At least one embodiment described may relate to an independent candidate beam RS list for beam failure recovery caused by CLI. In an exemplary embodiment, at 610, the WTRU may be configured with a first list (e.g., candidateBeamRSList) for legacy BFR and a second candidate beam RS list (e.g., candidateBeamRSList-CLI) to be used in the event that BFR is caused by CLI in XDD (or dynamic / flexible TDD). The list may include one or more indications of SSBs and / or CSI-RS that may be in different directions (e.g., the beams in candidateBeamRSList-CLI may be in a direction different from that affected by the victim WTRU).

[0254] In case of a BS switching to UL in a DL subframe, the BS may notify other BSs / WTRUs of the switch: For example, in case of inter-cell coordination, the aggressor BS may notify potential victim BSs through a backhaul connection. Otherwise, in case of no inter-cell coordination, the aggressor BS may send a specific signal in the window. The WTRUs may monitor the signal and detect the switch. The BSs may monitor the signal and notify the WTRUs that they may be affected by the switch.

[0255] When BFR is detected (at 612), the WTRU may determine at 614 whether it is due to CLI according to one or more methods or processes further described in detail herein, such as based on a combination of RSRP, L1-SINR, CLI-RSSI and / or SRS-RSRP.

[0256] In case the BFR is caused by CLI, the WTRU may select SSB or CSI-RS in the second list of reference signals (e.g., candidateBeamRSList-CLI) at 616. The WTRU may then proceed with the beam failure recovery request. In case the BFR is not caused by CLI, the WTRU may select SSB or CSI-RS in the first list of reference signals (e.g., candidateBeamRSList) at 618. The WTRU may then proceed with the beam failure recovery request.

[0257] At least one embodiment may relate to dynamic beam failure detection and recovery caused by CLI. In some embodiments, the WTRU may be configured to measure and report SRS-RSRP based on the SRS received from the potential aggressor WTRU. The SRS-RSRP report may be used at the BS to configure and select a candidate beam RS list (e.g., candidateBeamRSList-CLI or candidateBeamRSList#2 in WTRU capability set 2) in the event that the beam failure is caused by CLI. The WTRU may also process the SRS-RSRP in terms of power and / or beam direction. The WTRU may determine the type of BFD and whether it is due to CLI (based on a combination of assumed 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, where the assumed BLER>threshold, CLI<threshold; BFD Type 2, where the assumed BLER>threshold, CLI>threshold; BFD Type 3, where the assumed BLER<threshold, CLI>threshold; or BFD Type 4, where the assumed BLER<threshold, CLI<threshold.

[0258] In case the beam failure is caused by CLI, the WTRU may report and / or recommend candidate RS (SSB or CSI-RS) beams to be included in the candidate beam RS list (e.g., candidateBeamRSList-CLI or candidateBeamRSList#2 in WTRU capability set 2). For example, based on a combination of L1-RSRP and CLI measurements, the WTRU may determine the candidate RS beams. The WTRU may perform selection of the best beam from the candidate RS beams and based on a combination of L1-RSRP measurements and CLI measurements. If the WTRU determines that the BFR is due to CLI and UL-SCH is available, the WTRU generates and reports a BFR MAC CE to indicate beam failure detection, an index to the SSB or CSI-RS with RSRP above a threshold, and the like.

[0259] A panel switching mechanism in BFR is described herein. The WTRU may determine and report a corresponding 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 for sending and / or receiving as a WTRU capability value / set report. In some examples, the WTRU may include a parameter for the maximum number of supported layers (e.g., 4 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 Tx chains (or Tx / Rx 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 maximum number of 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.

[0260] As used herein, 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.

[0261] According to the description provided herein, for example, the WTRU may use / have / adopt, for example, two WTRU panels (WTRU Panel 1 and WTRU Panel 2 are used to communicate with the BS, for example, which may be reported based on WTRU capability values / aggregate reports), however the embodiments and processes discussed may equally be used in situations with more than two WTRU panels.

[0262] In an embodiment, the WTRU may use / activate the WTRU panel 1 to communicate with the BS, for example based on the outcome / result of the initial access procedure, based on an indication / configuration from the BS, and / or based on a WTRU initiated / directed / driven / triggered selection of an active WTRU panel. In some examples, using the WTRU panel 1 to communicate with the BS may imply that the WTRU may use the WTRU panel 1 to perform at least one of: 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.

[0263] 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 processes. 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 the ratio of channel to interference quality 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 assumed PDCCH RE energy to average SSS RE energy (e.g., assumed BLER), etc. The WTRU may determine, identify or receive configuration information for beam failure recovery (BFR). In some examples, the WTRU may receive configuration information for BFR that includes a list of candidate RS beams (e.g., candidateBeamRSList), a BFR maximum counter threshold (e.g., MaxCount), a set of uplink resources, or other parameters.

[0264] Hereinafter, the parameters described above (such as candidate RS beam list, maximum counter threshold, SS-RSRP threshold, CSI-RSRP threshold, SRS-RSRP threshold, and CLI-RSSI threshold) may be referred to as BFR parameters. A specific combination of such parameters may be referred to as a "BFR parameter set".

[0265] 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.

[0266] In an embodiment, a BFR parameter set may be associated with a WTRU capability value, set, and / or WTRU panel. In some examples, candidateBeamRSList#1 may be associated with (e.g., configured / indicated to be used with) WTRU capability set / panel 1, and candidateBeamRSList#2 may be associated with (e.g., configured / indicated to be used with) WTRU capability set / panel 2.

[0267] For the indication of the BFR parameter set, one or more of the following methods may be used. Figure 7 , at 710, explicit indication may be used, where the WTRU may receive configuration information indicating separate or different lists of BFR parameters (e.g., based on association with WTRU capability values, sets, or WTRU panels).

[0268] Implicit indication may be used, where the WTRU may receive configuration information indicating one or more BFR parameters, and the WTRU may determine, define or identify different or separate sets of BFR parameters (e.g., each corresponding to a respective WTRU capability value, set or WTRU panel) based on the configuration information.

[0269] The WTRU may group the BFR parameters into BFR parameter sets based on a priority. In some examples, the WTRU may determine the priority based on, for example, a WTRU panel ID associated with the BFR parameters. Thus, the WTRU may group the BFR parameters into BFR parameter sets based on the corresponding WTRU panel ID. For example, the WTRU may determine the BFR parameter set based on the candidate RS beams, wherein the WTRU may group the candidate RS beams based on a priority (e.g., based on the WTRU panel ID).

[0270] In some embodiments, the WTRU may monitor reference signals 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, in the event of a beam failure being detected, the WTRU triggers a beam recovery procedure.

[0271] A beam restoration procedure (BRP) is described herein. A WTRU may determine (e.g., based on WTRU panel 1 (being the currently activated / used WTRU panel)) that a beam failure detection has occurred and thus trigger a beam restoration procedure. According to one or more aspects described herein, the WTRU may determine whether the beam failure detection is due to an interfering signal (e.g., due to cross-link interference (CLI)), wherein the effect of the CLI may degrade (downlink) reception performance when receiving downlink signals via (using) the WTRU panel 1.

[0272] One or more of the following conditions may apply. The WTRU may determine the first set of BFR parameters (e.g., in response to determining that the first set of BFR parameters is associated with WTRU panel 1 (as the currently activated / used WTRU panel)). For example, referring to Figure 7 At 714, the WTRU may select a BFR parameter set (e.g., a first BFR parameter set) based on a priority (e.g., a panel ID of a panel that was being used when the beam failure was detected).

[0273] The WTRU may determine, identify, or use a first candidate RS beam list (e.g., candidateBeamRSList#1) from the first BFR parameter list. In some examples, the BS may configure / activate / indicate a first candidate RS beam list associated with WTRU panel 1 based on an efficient beam management strategy / procedure, for example, based on a recent beam report from the WTRU that notifies the BS of one or more preferred RS beam indices, each preferred RS beam index having 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 / update one or more preferred RS beam indices to be 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 of beam failure related processes, because based on the configured / indicated BFR process, the BS may first control the WTRU behavior of searching for a preferred RS beam within the first candidate RS beam list.

[0274] The WTRU may initiate a first BFR counter (eg, BFRcounter#1) based on a maximum counter threshold in a first set of BFR parameters (eg, MaxCount#1).

[0275] refer to Figure 7, at 716, the WTRU may select a candidate RS beam from the first candidate RS beam list. In one example, although the WTRU may be configured with more than one candidate RS beam list (e.g., each candidate RS beam list is associated with each WTRU panel), the WTRU may (be configured to) first search in the candidate RS beam list associated with the currently activated / used WTRU panel (e.g., WTRU panel 1) (e.g., the first candidate RS beam list) and not first search 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 / prioritized, etc.). This may provide benefits in terms of beam management efficiency and improved robustness of beam failure related procedures because the BS may first control the WTRU behavior of searching for a preferred RS beam within the first candidate RS beam list based on the configured / indicated BFR procedures.

[0276] The WTRU may measure the radio link and / or beam quality (e.g., SS-RSRP, CSI-RSRP, signal-to-interference-plus-noise ratio (SINR) value, SSB-based SINR, CSI-SINR, etc.) of the selected candidate RS beam.

[0277] The WTRU may compare the channel quality measurement results with corresponding channel / beam quality thresholds (e.g., SSB-RSRP threshold, CSI-RSRP threshold, SINR threshold, SSB-based SINR threshold, CSI-SINR threshold, etc.) from the first BFR parameter list.

[0278] In some cases, if the measured channel / beam parameters are above corresponding thresholds (or in addition to the above measurements, or together with the above measurements, e.g., to ultimately combine together to determine actions during the BFR process (e.g., candidate beam selection / reporting / request)), the WTRU may measure interference based on interference measurement reference signals and resources (e.g., at least one of SRS-RSRP, CLI-RSSI, CSI-RS interference measurement resources (IMR), predefined / preconfigured interference measurement methods based on configured / indicated RS, etc.). In some examples, the WTRU may measure interference (i.e., SRS-RSRP) based on the configured / indicated SRS signal / configuration and in the configured / indicated time and frequency resources. In one example, the configured / indicated SRS signal / configuration may correspond to an SRS that is (e.g., to be) transmitted from a second WTRU (e.g., as a (potential) aggressor WTRU, a WTRU in a neighboring cell / TRP, etc.). This may provide the benefit that such CLI-related measurements may be considered when deriving / selecting preferred candidate beams as part of the BFR process. In some examples, the WTRU may measure the CLI-RSSI based on the configured reference signal and in the configured time and frequency resources. This may provide the following benefits: the WTRU may apply / use the CLI-RSSI measurement in deriving / selecting preferred candidate beams as part of the BFR process, for example, based on the overall interference level including CLI impact, etc.

[0279] The WTRU may compare the channel quality measurement parameters with the interference measurement parameters. In some examples, the WTRU may compare the interference measurement results with corresponding 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 hypothetical measurement result (e.g., a hypothetical BLER) based on comparing the channel / beam quality measurement results with the interference measurement results (e.g., based on a ratio of the channel quality measurement results to the interference measurement results).

[0280] refer to Figure 7 , at 720, the WTRU may determine whether the candidate beam is a preferred beam to be selected for performing the beam recovery procedure. The WTRU may report one or more of the preferred candidate beams. In an embodiment, the indication may be via MAC-CE or CF-RACH. The WTRU may receive an acknowledgement message from the BS (e.g., by receiving a PDCCH in a corresponding BFR CORESET), for example, indicating whether the beam is preferred or non-preferred.

[0281] 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 lower channel quality measurement compared to a corresponding threshold; a high interference measurement compared to a corresponding threshold; a low ratio of channel quality measurement to interference measurement compared to a corresponding threshold; or a condition where the WTRU does not receive an acknowledgement from the BS on the reported preferred candidate beam (e.g., no PDCCH transmission is received via the BFRCORESET, or another downlink signal, or a given duration expires before receiving an acknowledgement, etc.).

[0282] The WTRU may determine the next candidate beam. One or more of the following steps may be taken. 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 a first BFR parameter set.

[0283] like Figure 7 As shown, at 718, if the first BFR counter does not reach 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.

[0284] The WTRU may measure channel quality parameters and interference parameters based on applying at least one of the above actions / processes / steps (eg, based on the above steps) to the selected candidate beam.

[0285] In the event that a BFR-related counter (e.g., a first BFR counter) has reached a maximum counter threshold in the first BFR parameter set, the WTRU may follow the procedure to search for other candidate beam RSs (e.g., within a second candidate RS beam list, and / or apply automatic panel switching).

[0286] Methods for automatic panel switching are described herein. A WTRU may determine that a first BFR counter and / or a first WTRU panel (e.g., BFRcounter#1) associated with a first BFR parameter set has reached a first maximum counter threshold (e.g., MaxCount#1). Therefore, the WTRU may determine to switch to a second BFR parameter set (e.g., a second WTRU panel). One or more of the following steps or processes may be taken.

[0287] The WTRU may determine, identify, or use a second candidate RS beam list from a second BFR parameter list (eg, candidateBeamRSList#2).

[0288] The WTRU may, for example, in response to 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), reset the BFR counter or initiate a second BFR counter (e.g., BFRcounter#2) based on a maximum counter threshold (e.g., MaxCount#2) in a second BFR parameter set.

[0289] The WTRU may select a candidate RS beam from a second candidate RS beam list (eg, associated with a second WTRU panel, which may be based on at least one of the WTRU capability values / sets).

[0290] The WTRU may measure the radio link and / or beam quality (eg, SS-RSRP, CSI-RSRP, SINR value, SSB-based SINR, CSI-SINR, etc.) of the selected candidate RS beam.

[0291] The WTRU may compare the channel quality measurement results with corresponding channel / beam quality thresholds (e.g., SSB-RSRP threshold, CSI-RSRP threshold, SINR threshold, SSB-based SINR threshold, CSI-SINR threshold, etc.) from the second BFR parameter list.

[0292] If the measured channel / beam parameter is above a corresponding threshold (either in addition to the above measurements, or together with the above measurements, e.g., to ultimately combine together to determine actions during the BFR process (e.g., candidate beam selection / reporting / request)), the WTRU may measure interference based on interference measurement reference signals and resources (e.g., at least one of SRS-RSRP, CLI-RSSI, CSI-RS interference measurement resources (IMR), predefined / preconfigured interference measurement methods based on configured / indicated RS, etc.). In some examples, the WTRU may measure SRS-RSRP based on the configured / indicated SRS signal / configuration and in the configured / indicated time and frequency resources. In some examples, the configured / indicated SRS signal / configuration may correspond to an SRS to be (e.g., to be) sent from a second WTRU (e.g., as a (potential) aggressor WTRU, a WTRU in a neighboring cell / TRP, etc.). This may provide the benefit that such CLI-related measurements may be considered when deriving / selecting preferred candidate beams as part of the BFR process. In some examples, the WTRU may measure the CLI-RSSI based on the configured reference signal and in the configured time and frequency resources. This may provide the following benefits: the WTRU may apply / use the CLI-RSSI measurement in deriving / selecting preferred candidate beams as part of the BFR process, for example, based on the overall interference level including CLI impact, etc.

[0293] The WTRU may compare the channel quality measurement parameter with the interference measurement parameter. In some examples, the WTRU may compare the interference measurement result with a corresponding channel / beam interference threshold (e.g., CLI-RSSI threshold, SRS-RSRP threshold, CSI-IMR threshold, etc.) from the second BFR parameter list. In some examples, the WTRU may estimate a hypothetical measurement result (e.g., a hypothetical BLER) based on comparing the channel / beam quality measurement result with the interference measurement result (e.g., based on a ratio of the channel quality measurement result to the interference measurement result).

[0294] The WTRU may determine whether a candidate beam is a preferred beam to be selected for performing the beam recovery procedure.

[0295] The WTRU may report one or more preferred candidate beams among the preferred candidate beams. The WTRU may receive an acknowledgement from the BS (e.g., by receiving a PDCCH in a corresponding BFR CORESET, or by receiving another logically equivalent message). In response to receiving the acknowledgement, the WTRU may begin using or be configured to begin using (e.g., switch to, update to and / or deactivate a first WTRU panel and begin using, etc.) a second WTRU panel to communicate with the BS based on (using) the candidate beams. Using the second WTRU panel based on the candidate beams may include communicating with the BS based on a second spatial domain filter, which is determined based on the candidate beams, which candidate beams may be included in the second candidate RS beam list and confirmed by the BS based on the acknowledgement. This may provide benefits in terms of reduced overhead and latency relative to the WTRU panel switching / selection process, because the WTRU may change / switch its panel (from a first WTRU panel to a second WTRU panel) to communicate with the BS based on at least one embodiment or solution as described herein, for example, without a separate / explicit WTRU panel switching indication and / or process. This may provide benefits in the sense of automatic WTRU panel switching.

[0296] 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 lower channel quality measurement compared to a corresponding threshold; a high interference measurement compared to a corresponding threshold; a low ratio of channel quality measurement to interference measurement compared to a corresponding threshold, or a situation where the WTRU does not receive an acknowledgement from the BS on the reported preferred candidate beam (e.g., no PDCCH is received via BFR CORESET or another logically equivalent message, or a given duration is exceeded before an acknowledgement is received, etc.).

[0297] The WTRU may determine the next candidate beam. One or more of the following steps or processes may be taken. The WTRU may increment a second BFR counter (e.g., BFRcounter#2) by 1. The WTRU may compare the second BFR counter with a maximum counter threshold (e.g., MaxCount#2) in a second BFR parameter set. In the event that the second BFR counter does not reach 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 applying at least one of the above actions / processes / steps to the selected candidate beam (e.g., based on the above steps).

[0298] In case the second BFR counter has reached the maximum counter threshold in the second BFR parameter set, the WTRU may follow the procedure of the contention based random access procedure.

[0299] Embodiments involving independent BFR parameter sets for beam failure recovery are described herein. In some embodiments, the WTRU may use, determine, or be configured with at least two BFR parameter sets, and each BFR parameter set may be associated with an operating mode. For example, if the WTRU determines and / or identifies a first operating mode, the WTRU may use, determine, or identify a BFR parameter configuration based on the first BFR parameter set. Alternatively or additionally, if the WTRU determines and / or identifies a second operating mode, the WTRU may use, determine, or identify a BFR parameter configuration based on a second BFR parameter set. Parameters that affect the operating mode are defined as follows.

[0300] The parameter may include a duplex mode (e.g., TDD, FDD, or XDD). For example, if the WTRU operates in TDD mode, the WTRU may determine the BFR parameters based on a first set of BFR parameters. If the WTRU operates in FDD mode, the WTRU may determine the BFR parameters based on a second set of BFR parameters. Additionally, if the WTRU operates in XDD mode in the corresponding sub-band, the WTRU may determine the BFR parameters based on a third set of BFR parameters.

[0301] The parameters may include the cause of the BFD. For example, if the WTRU determines that the BFD is due to beam quality degradation (e.g., due to beam blocking), the WTRU may determine the BFR parameters based on a first set of BFR parameters. If the WTRU determines that the BFD is caused by an interfering signal (e.g., CLI in XDD), the WTRU may determine the BFR parameters based on a second set of BFR parameters.

[0302] The parameter may include a sub-band range. For example, if the WTRU determines that the WTRU is not affected / interfered by CLI in XDD operation in the corresponding sub-band, the WTRU may determine the BFR parameter based on a first set of BFR parameters. If the WTRU determines that the WTRU may be affected / interfered by CLI from a potential aggressor cell, BS, and / or WTRU in XDD operation in the corresponding sub-band, the WTRU may determine the BFR parameter based on a second set of BFR parameters.

[0303] The parameter may be determined based on the beam failure recovery procedure. For example, if the WTRU is operating a full BFR procedure, the WTRU may determine the BFR parameter based on a first set of BFR parameters. If the WTRU is operating in a partial BFR procedure, the WTRU may determine the BFR parameter based on a second set of BFR parameters.

[0304] The parameters may be based on a licensing scheme. For example, if the WTRU operates with shared spectrum channel access, the WTRU may determine the BFR parameters based on a first set of BFR parameters. If the WTRU operates without shared spectrum channel access, the WTRU may determine the BFR parameters based on a second set of BFR parameters.

[0305] The parameters may be based on the 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 set of BFR parameters. If the WTRU determines a second use case, the WTRU may determine the BFR parameters based on a second set of BFR parameters.

[0306] The parameter may be based on a barring of the WTRU type (e.g., access barring of a specific WTRU type). For example, if the WTRU is not allowed to access a cell, a first type of WTRU (e.g., a WTRU with limited capabilities including reduced Rx antennas, a smaller maximum bandwidth supported, a lower maximum transmit power) may determine the BFR parameter based on a first set of BFR parameters. Otherwise, if the first type of WTRU is allowed to access the corresponding cell, the first type of WTRU may determine the BFR parameter based on a second set of BFR parameters.

[0307] The parameter may be based on one or more other parameters, such as parameters for a beam, TCI, TRP, and / or WTRU panel. For example, in response to determining 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 (e.g., based on at least one of the embodiments of the present disclosure) is associated with a first set of BFR parameters (e.g., based on an explicit indication from the BS), the WTRU may determine the BFR parameters based on the first set of BFR parameters. In response to determining 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 (e.g., based on at least one of the embodiments of the present disclosure) is associated with a second set of BFR parameters (e.g., based on an explicit indication from the BS), the WTRU may determine the BFR parameters based on the second set of BFR parameters.

[0308] The parameters may be based on support for specific functionality in the network (e.g., power saving, carrier aggregation, DRX, etc.). For example, if the WTRU determines a first functionality in the network, the WTRU may determine the BFR parameters based on a first set of BFR parameters. If the WTRU determines a second functionality in the network, the WTRU may determine the BFR parameters based on a second set of BFR parameters.

[0309] In some examples, the WTRU may be configured with a first BFR parameter set including 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 including one or more second CBFR-RS lists (e.g., candidateBeamRSList-CLI). In one example, the second BFR parameter set and the corresponding CBFR-RS list may be used in the case where the BFD is caused by the CLI in the XDD. One or more of the following steps or processes may be taken.

[0310] For a single TRP scheme, 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, the two sets being provided based on candidateBeamRSList and candidateBeamRSList_CLI, respectively. For a multi-TRP scheme, the WTRU may use, determine, or be configured with a first BFR parameter set including first two sets q1,0 and q1,1, the first two sets being provided based on candidateBeamRSList1 and candidateBeamRSList2, respectively. For a multi-TRP scheme, the WTRU may use, determine, or be configured with a second BFR parameter set including, for example, second two sets q1,0_CLI and q1,1_CLI, the second two sets being provided based on candidateBeamRSList1_CLI and candidateBeamRSList2_CLI, respectively.

[0311] In some examples, the WTRU may be configured with a first BFR parameter set that includes 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 that includes 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 in the case where the BFD is caused by CLI in the XDD.

[0312] Embodiments involving potential CLI indications are described herein. In some embodiments, a WTRU may determine whether potential cross link interference (CLI) in a sub-band may affect the beam and / or channel quality of the WTRU. For example, potential CLI may be due to a change in the transmission direction in a neighboring cell in an XDD (or dynamic / flexible TDD) framework. For example, a change in the signal transmission direction from downlink (DL) to uplink (UL) in a neighboring cell may result in a UL to DL CLI from a potential aggressor WTRU on a victim WTRU in a serving cell with DL transmissions.

[0313] The WTRU may determine the potential CLI based on, for example, an explicit or implicit indication. In the case of an explicit indication, the WTRU may receive an indication trigger or indication (e.g., via a DCI, MAC-CE, or logically equivalent message) that the potential CLI may exist or affect the channel and / or beam quality of the WTRU in the corresponding sub-band. In some examples, the potential aggressor BS / cell may indicate to the serving BS / cell (e.g., via backhaul signaling in the presence of inter-cell signaling) that the transmission direction will change in the sub-band.

[0314] 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 logically equivalent messages) that potential CLI may exist or affect the channel and / or beam quality of the WTRU in the corresponding sub-band. In some examples, the potential aggressor BS / cell may send a (pre)configured signal in a window (e.g., in a time domain and / or 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 preconfigured signal, the WTRU may receive information indicating a trigger or an indication from the serving cell that potential CLI may exist or affect the channel and / or beam quality of the WTRU in the corresponding sub-band.

[0315] 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 potential CLI may exist or affect the channel and / or beam quality of the WTRU in the corresponding sub-band.

[0316] The beam failure recovery process is further described herein. In some embodiments, the WTRU may determine that the BFR process is triggered. The WTRU may determine, identify, or be configured that potential CLI may exist or affect the channel and / or beam quality of the WTRU in the corresponding sub-band. The WTRU may determine and / or identify whether the BFR is caused by an interfering signal (e.g., due to cross-link interference (CLI) in XDD), for example, according to one or more methods or processes described herein. One or more of the following conditions, steps, or processes may apply.

[0317] In some cases, if the WTRU determines that the BFD is due to an interfering signal (e.g., due to cross-link interference (CLI) in XDD), the WTRU may determine a second BFR parameter set (e.g., corresponding to a parameter configuration due to CLI). In some cases, the WTRU may determine, identify, or use a second candidate RS beam list from a second BFR parameter list (e.g., candidateBeamRSList_CLI). In some cases, the WTRU may initiate 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 radio link and / or beam quality (e.g., SS-RSRP, CSI-RSRP, etc.) of the selected candidate RS beam. In some cases, the WTRU may compare the channel quality measurement result with a corresponding channel / beam quality threshold (e.g., SSB-RSRP_CLI, CSI-RSRP_CLI, etc.) from the second BFR parameter list.

[0318] In some embodiments, if the measured channel / beam parameters are above the corresponding thresholds, the WTRU may measure interference based on the interference measurement reference signal and resources. In some examples, the WTRU may measure channel quality (e.g., SRS-RSRP) based on the configured SRS signal and in the configured time and frequency resources. In some examples, the WTRU may measure channel quality (e.g., CLI-RSSI) based on the configured reference signal and in the configured time and frequency resources.

[0319] The WTRU may compare the channel quality measurement parameter with the interference measurement parameter. In some examples, the WTRU may compare the interference measurement result with a corresponding channel / beam interference threshold (e.g., SRSrsrpThreshold_CLI, CLIrssiThreshold_CLI, etc.) from the second BFR parameter list. In some examples, the WTRU may estimate a hypothetical measurement result (e.g., a hypothetical BLER) based on comparing the channel / beam quality measurement result with the interference measurement result (e.g., based on a ratio of the channel quality measurement result to the interference measurement result).

[0320] 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 preferred candidate beams among the preferred candidate beams. The WTRU may receive information confirming the preferred beam from the BS (e.g., by receiving a PDCCH in a corresponding BFR CORESET, or another logically equivalent message). In response to receiving the confirmation, the WTRU may begin using or be configured to begin using (e.g., switch to, update to) the candidate beam for communicating with the BS. The use of the candidate beam for communicating with the BS may include communicating with the BS based on a second spatial domain filter, the second spatial domain filter being determined based on the candidate beam, the candidate beam being included in a second candidate RS beam list and confirmed by the BS based on the confirmation.

[0321] The WTRU may determine that a candidate beam is not a preferred beam. For example, the beam may not be selected as a preferred beam due to one or more of the following: a lower channel quality measurement compared to a corresponding threshold; a high interference measurement compared to a corresponding threshold; a low ratio of channel quality measurement to interference measurement compared to a corresponding threshold; or no confirmation is received from the BS on the reported preferred candidate beam (e.g., no PDCCH is received by the BFR CORESET, or another logically equivalent message).

[0322] The WTRU may determine the next candidate beam. One or more of the following conditions, steps, or processes may be applicable or may be taken. For example, the WTRU may increment the BFR counter by 1. The WTRU may compare the BFR counter with a maximum counter threshold (e.g., MaxCount_CLI) in a second BFR parameter set. In the event that 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 above steps for the selected candidate beam. In the event that 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). In the event that the BFR counter has reached the maximum counter threshold in all BFR parameter sets, the WTRU may follow the process of the contention-based random access procedure.

[0323] Methods and processes for dynamic beam failure detection and recovery are described herein.

[0324] Some embodiments for beam failure detection may consider the type of BFD identity. In some embodiments, the WTRU may determine whether the BFD is caused by an interfering signal. For example, when operating in the XDD (or dynamic / flexible TDD) mode, the WTRU may determine whether the BFD is caused by a CLI from a potential aggressor cell, BS, or WTRU. In addition to the interfering signal quality / intensity (e.g., CLI-RSSI, SRS-RSRP), the WTRU may also 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, hypothesized BLER). The WTRU may compare the channel / beam measurement quality (CBMQ) with the corresponding channel / beam measurement threshold (CBMT). The WTRU may compare the interference measurement quality / intensity (IMQ) with the corresponding interference measurement threshold (IMT).

[0325] In some embodiments, the WTRU may determine different types of beam failure detection based on a combination of the CBMQ and IMQ results and according to the corresponding thresholds

[0326] to determine different types of beam failure detection. Thus, the WTRU may determine one or more operating modes and WTRU behaviors based on the determined BFD type. One or more of the following conditions, steps, or processes may apply.

[0327] One type of BFD may be referred to as BFD type 1. In the case of a type 1 BFD, the WTRU may determine that the channel / beam quality is below the corresponding threshold while the interference quality / intensity is below the corresponding threshold (e.g., CBMQ < CBMT and IMQ < IMT). The WTRU may thus determine the operating mode. For example, the WTRU may determine that the BFD may be caused by reasons other than a CLI from an aggressor WTRU or BS in the XDD mode. As such, the WTRU may initiate a beam failure recovery process (e.g., a random access process) based on a first set of BFR parameters corresponding to a beam failure caused by reasons other than interference and / or CLI.

[0328] Another type of BFD may be referred to as BFD type 2. In the case of type 2 BFD, the WTRU may determine that the channel / beam quality is below a corresponding threshold, while the interference quality / intensity is greater than or equal to a corresponding acceptable threshold and / or an out-of-sync indication (e.g., CBMQ < CBMT and IMQ >= IMT). The WTRU may thus determine the operation mode. For example, the WTRU may determine that the BFD may be due to CLI from an aggressor WTRU or BS in XDD mode. As such, the WTRU may initiate a beam failure recovery procedure (e.g., a random access procedure) based on a second set of BFR parameters corresponding to the beam failure caused by interference (e.g., CLI). In some examples, in the case where the WTRU has determined that the BFD is due to interference (e.g., CLI), the WTRU may verify or determine whether the uplink channel is available. In the case where the WTRU determines that the uplink channel is available, the WTRU may thus initiate a BFD procedure (e.g., based on a BFR MAC-CE or another logically equivalent message).

[0329] Another type of BFD may be referred to as BFD type 3. In the case of type 3 BFD, the WTRU may determine that the channel / beam quality is greater than or equal to a corresponding threshold, while the interference quality / intensity is greater than or equal to a corresponding acceptable threshold (e.g., CBMQ > CBMT and IMQ >= IMT).

[0330] In an embodiment, the WTRU may thus determine the operation mode. In some embodiments, the WTRU may determine that the BFD and / or a partial BFD may be due to CLI from an aggressor WTRU or BS in XDD mode. As such, the WTRU may initiate a beam failure recovery procedure (e.g., a random access procedure) based on a second set of BFR parameters corresponding to the beam failure caused by interference (e.g., CLI). In some examples, in the case where the WTRU has determined that the BFD is due to interference (e.g., CLI), the WTRU may verify or determine whether the uplink channel is available. In the case where the WTRU determines that the uplink channel is available, the WTRU may thus initiate a BFD procedure (e.g., based on a BFR MAC-CE or another logically equivalent message). Alternatively or additionally, in some examples, the WTRU may measure, estimate, and / or determine the received power and the beam direction from which it receives interference (e.g., CLI). As such, the WTRU may thus (e.g., dynamically) determine a preferred BFR RS beam. The WTRU may then further report the preferred candidate BFR RS beam. Additionally, the WTRU may also use the information on the power and the beam direction from which it receives interference (e.g., CLI). In one example, the WTRU may thus select, estimate, and / or determine a precoding matrix indicator (PMI) in a CSI-RS report.

[0331] Methods and processes for candidate beam RS recommendation and / or reporting are described herein. In some embodiments, in addition to interference (e.g., CLI) measurements, the WTRU may also use the results from channel / beam measurements to dynamically recommend / report (e.g., to the serving cell / BS) a preferred and / or optimal set of BFR parameters, for example, via a MAC-CE in the UL direction. In this way, the WTRU may associate the results from the channel / beam measurements with the interference measurement results to determine the power / strength and / or beam direction of potential interference sources (e.g., from an aggressor cell, BS, WTRU's CLI in XDD mode).

[0332] In some examples, the WTRU may measure, estimate and / or determine the beam direction of potential interference (e.g., CLI) from an aggressor cell, BS and / or WTRU. The WTRU may then refine, update and / or recommend (e.g., to a serving cell / BS) a list of candidate beam REs that are preferably used in the event of a BFD due to a corresponding interfering signal (e.g., CLI).

[0333] In some embodiments, the WTRU may measure, estimate and / or determine the power / strength and / or beam direction of the interfering signal to determine the best beam selection from the candidate RS beams in the event of BFR due to the interfering signal (e.g., CLI). In this way, the WTRU may use a combination and / or correlation of channel and interference measurements to select the best beam during the beam recovery process.

[0334] 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 whether an uplink channel is available during the beam failure recovery procedure. In some examples, during the beam failure recovery procedure, the WTRU may determine that the beam failure detection may be caused by, for example, an interfering signal on a downlink channel / beam in the corresponding sub-band (e.g., CLI in XDD (or dynamic / flexible TDD)). In this way, the uplink channel (e.g., UL-SCH) is available for use by the WTRU.

[0335] In some embodiments, if the WTRU determines that the uplink channel is available during the channel recovery process, the WTRU may generate and transmit a message, such as a BFR MAC-CE, to indicate beam failure detection. In one example, the message may include an indication of the index of the SSB and / or CSI-RS with an RSRP above a threshold, etc.

[0336] Methods and procedures for sub-band based CLI detection are described herein.A WTRU may be configured to monitor, estimate and / or measure reference signals from a beam failure detection set (eg, q0 list).

[0337] In some embodiments, the WTRU may be configured with a subset of one or more time and / or frequency masks (e.g., configurations, parameters, windows, references, etc.). In one example, the WTRU may use the time and / or frequency masks to determine one or more sets of sub-bands and / or time slots. In this way, the WTRU may monitor, estimate and / or measure reference signals from a beam failure detection set (e.g., q0 list) based on the received, configured or determined time and / or frequency masks.

[0338] In some embodiments, the WTRU may monitor, estimate and / or measure interference (e.g., CLI) on sub-bands 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, if the quality / SINR of q0 on the resource mask is higher than the quality / SINR of q0 plus a configured threshold, the WTRU may determine that the BFD is due to CLI. In some examples, the serving cell may configure the time and / or frequency mask so that there is no interference (e.g., CLI) on the corresponding time and frequency resources.

[0339] Although features and elements are described above in specific combinations, it will be understood by those of ordinary skill in the art that each feature or element may be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (sent via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as built-in hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile disks (DVDs)). A processor associated with software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A beam failure detection method performed by a wireless transmit receive unit (WTRU) having multiple antenna panels, the method comprising: receiving configuration information, the configuration information comprising a plurality of beam failure recovery (BFR) parameter sets, wherein each BFR parameter set comprises a corresponding set of candidate beam reference signals (RS), a measurement criterion, and an interference criterion; Detect beam failures; determining the first BFR parameter set from the plurality of BFR parameter sets based on a priority of the first BFR parameter set, wherein the priority of the first BFR parameter set is determined based on which panel of the plurality of antenna panels is active or based on a received indication; as well as Under the condition 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: selecting a candidate beam RS that satisfies the measurement criterion and the interference criterion from the set of candidate beam RSs in the first BFR parameter set, and An indication indicating the selected candidate beam RS is sent.

2. The method of claim 1, wherein the measurement criterion is Reference Signal Received Power (RSRP).

3. The method of claim 1 or 2, wherein the interference criterion is based on a Cross-Link Interference Received Signal Strength Indicator (CLI-RSSI).

4. The method according to any one of claims 1 to 3, wherein the first BFR parameter set is associated with a first antenna panel among the plurality of antenna panels under the condition that the first antenna panel is active, and the priority of the first BFR parameter set is based on the highest priority of the first antenna panel being active.

5. The method according to any one of claims 1 to 4, wherein under the condition that no candidate beam RS in the set of candidate beam RSs of the first BFR parameter set is determined to satisfy both the measurement criterion and the interference criterion; the second BFR parameter set is selected from the multiple BFR parameter sets based on the priority of the second BFR parameter set.

6. The method according to any one of claims 1 to 5, further comprising sending a message indicating the number of available antenna panels.

7. The method according to any one of claims 1 to 6, wherein each BFR parameter set further includes at least one of the following: a list of beams for the WTRU to monitor, a BFR counter threshold, and a set of uplink resources.

8. The method according to any one of claims 1 to 7, wherein the WTRU operates in a cross-split duplex mode or a dynamic time division duplex mode.

9. The method according to any one of claims 1 to 8, further comprising receiving confirmation of the selected candidate beam.

10. The method according to any one of claims 1 to 8, further comprising: In case the WTRU does not receive an acknowledgement of the selected candidate beam, a second candidate beam is selected and an indication indicating the selected second candidate beam is sent.

11. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: multiple antenna panels; and A circuit, the circuit being configured as: receiving configuration information, the configuration information comprising a plurality of beam failure recovery (BFR) parameter sets, wherein each BFR parameter set comprises a corresponding set of candidate beam reference signals (RS), a measurement criterion, and an interference criterion; Detect beam failures; determining the first BFR parameter set from the plurality of BFR parameter sets based on a priority of the first BFR parameter set, wherein the priority of the first BFR parameter set is determined based on which panel of the plurality of antenna panels is active or based on a received indication; as well as Under the condition 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: selecting a candidate beam RS that satisfies the measurement criterion and the interference criterion from the set of candidate beam RSs in the first BFR parameter set, and An indication indicating the selected candidate beam RS is sent.

12. The WTRU of claim 11, wherein the measurement criterion is reference signal received power (RSRP).

13. The WTRU of claim 11 or 12, wherein the interference criterion is based on a Cross-Link Interference Received Signal Strength Indicator (CLI-RSSI).

14. The WTRU according to any one of claims 11 to 13, wherein the first BFR parameter set is associated with a first antenna panel among the plurality of antenna panels under the condition that the first antenna panel is active, and the priority of the first BFR parameter set is based on the highest priority of the first antenna panel being active.

15. The WTRU according to any one of claims 11 to 14, wherein under the condition that no candidate beam RS in the set of candidate beam RSs of the first BFR parameter set is determined to satisfy both the measurement criterion and the interference criterion; the second BFR parameter set is selected from the multiple BFR parameter sets based on the priority of the second BFR parameter set.

16. The WTRU of any one of claims 11 to 15, further configured to send a message indicating the number of available antenna panels.

17. The WTRU according to any one of claims 11 to 16, wherein each BFR parameter set further includes at least one of the following: a list of beams for the WTRU to monitor, a BFR counter threshold, and a set of uplink resources.

18. The WTRU of any one of claims 11 to 17, wherein the WTRU is configured to operate in a cross-split duplex mode or a dynamic time division duplex mode.

19. The WTRU of any one of claims 11 to 18, wherein the WTRU is further configured to receive confirmation of the selected candidate beam.

20. The WTRU according to any one of claims 11 to 19, the WTRU is further configured to select a second candidate beam and send an indication indicating the selected second candidate beam if the WTRU does not receive a confirmation of the selected candidate beam.

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