Dynamic determination of beam failure recovery mode

Abstract

A WTRU receives configuration information for beam failure recovery (BFR) including a set of beam failure detection (BFD) reference signals (RSs), a set of new candidate beam (NCB) RSs for QCL Type D, a set of new NCB RSs for other QCL Type, a set of RS for determining a BFR mode and corresponding thresholds for WTRU rotation, WTRU movement and maximum permissible exposure (MPE). The WTRU measures the set of BFD RSs to determine a BFR mode, wherein if an indicated MPE, WTRU rotation and WTRU movement are smaller than the corresponding thresholds, the WTRU determines BFR for other QCL Type, and otherwise, the WTRU determines BFR for QCL Type D. Additional embodiments are disclosed.

Description

DYNAMIC DETERMINATION OF BEAM FAILURE RECOVERY MODECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 526,828, filed July 14, 2023, the contents of which are incorporated herein by reference.BACKGROUND

[0002] New Radio (NR) introduced radio access technology (RAT) in frequency range 2 (FR2), where FR2 denotes the frequency range of 24.25 - 52.6 GHz One of key challenge of FR2 is higher propagation loss. Since propagation loss increases as carrier frequency increases, FR2 experiences the higher propagation loss. In order to overcome the higher propagation loss, efficient usage of highly directional beamformed transmissions and receptions is desirable.

[0003] Beamforming gain can be achieved by adding or subtracting one signal from another signal. Since more beamforming gain can be achieve as more signals are added or subtracted, utilization of large number of antenna elements are helpful for the highly directional beamformed transmission. Controlling signal addition or signal subtraction can be done by controlling phases of respective antenna elements.

[0004] Traditionally, a mobile device such as user equipment (UE), alternatively referred to a wireless transmit receive unit (WTRU), decides its own reception beam based on transmission control indicator (TCI) states provided by gNB indication. However, for artificial intelligence / machine learning (AI / ML) based beam prediction, a concept of beam pair prediction and indication has been proposed. The beam pair prediction estimates not only qualities of gNB Tx beams but also qualities of a pair of a gNB Tx beam and a WTRU Rx beam. As the beam pair prediction considers both Tx beams and Rx beams, performance of the beam pair prediction is expected to be higher than the beam prediction for DL Tx beams alone. However, beam pair prediction may be less reliable in some cases such as WTRU rotation and maximum permissible exposure (MPE). Methods and systems are needed for determining how to decide a beam management mode in a WTRU, i.e., between a Tx beam mode and a beam pair mode for beam indication, beam failure recovery and / or beam reporting.SUMMARY

[0005] Aspects of focus solution embodiments described herein may use dynamic determination on a beam failure recovery (BFR) mode or BFR mode based on multiple BFR sets. In an example of determination on a BFR mode, the WTRU receives a configuration of beam failure recovery (BFR) including one or more of the following: (i) a set of beam failure detection (BFD) RSs; (ii) a set of new candidate beam (NCB) RSs for QCL Type D (e.g., with multiple Tx beams); (iii) a set of new NCB RSs for another QCL Type (e.g., with a best beam and repetition); (iv) a set of RSs for determining a BFR mode; and / or (v) corresponding thresholds for one or more of MPE, WTRU rotation and WTRU movement.

[0006] The WTRU then measures the set of BFD RSs for determining a BFR mode and determines a mode of operation for the BFR. If one or more of the indicated MPE, WTRU rotation and WTRU movement is smaller than the corresponding thresholds, the WTRU determines the BFR for the other QCL Type. If one or more of the indicated MPE, WTRU rotation and WTRU movement is larger than the corresponding thresholds, the WTRU determines BFR for QCL Type D. Next, the WTRU monitors the set of BFD RSs for beam failure detection. If the WTRU detects the number of beam failure instances are greater than a corresponding threshold, then the WTRU starts beam failure recovery procedure based on the determined BFR mode. If the BFR for the other QCL Type is determined, the WTRU measures the set of NCB RSs for the other QCL Type and identifies one or more IDs for the other QCL Type greater than a corresponding threshold.

[0007] If the WTRU identifies the one or more IDs for the other QCL Type, the WTRU transmits a physical random access channel (PRACH) associated with the one or more best RSs for other QCL Types. In the case that the WTRU does not identify the one or more best IDs for the other QCL Type (e.g., within a timer or a counter), the WTRU starts a BFR procedure for QCL Type D When the BFR for QCL Type D is determined or the BFR for the other QCL Type is failed, the WTRU measures the set of NCB RSs for QCL Type D and identifies one or more best RSs for QCL Type D greater than a corresponding threshold. When the WTRU identifies the one or more best RSs for QCL Type D, the WTRU transmits a PRACH associated with the one or more best RSs for QCL Type D. The WTRU receives a confirmation (e.g., by receiving a PDCCH via an associated CORESET / SS with the BFR).

[0008] In an example of dynamic determination of BFR mode based on multiple BFR sets, the WTRU receives a configuration of a set of RSs for determining a BFR mode, thresholds for one or more of MPE, WTRU rotation and WTRU movement and two or more beam failure recovery (BFR) sets for TX beam recovery and Rx beam recovery. Each BFR set includes one or more of the following: (i) a set of beam failure detection (BFD) RSs; (ii) a set of new candidate beam (NCB) RSs; one or more Search Spaces / CORESETs; and / or (iii) one or more UL resources (e.g., PRACH resources).

[0009] Next, the WTRU measures the set of BFD RSs for determining a BFR mode and determines a mode of operation for BFR If one or more of the indicated MPE, WTRU rotation and WTRU movement is smaller than the corresponding thresholds, the WTRU activates a BFR set for the other QCL Type. If one or more of the indicated MPE, WTRU rotation and WTRU movement is larger than the corresponding thresholds, the WTRU determines a BFR for QCL Type D.

[0010] If the BFR set for the other QCL Type is activated, the WTRU monitors the set of BFD RSs in the BFR set for the other QCL Type. If the WTRU detects beam failure instance greater a corresponding threshold, then the WTRU starts a beam failure recovery procedure in which the WTRU measures the set of NCB RSs in the set for the other QCL Type and identifies one or more best IDs greater than a corresponding threshold. Upon the WTRU identifying the one or more best IDs, the WTRU transmits a PRACH associated with the one or more best Rx IDs. If the WTRU does not identify the one or more best IDs (e.g., within a timer or a counter), the WTRU starts a BFR procedure based on the BFR set for QCL Type D.

[0011] If the BFR set for QCL Type D is activated or the BFR procedure for the other QCL Type is failed, the WTRU monitors / measures the set of BFD RSs in the BFR set for QCL Type D If the WTRU detects beam failure instance greater than a corresponding threshold, then the WTRU starts a beam failure recovery procedure (possibly only for Tx beam recovery activation). The WTRU measures the set of NCB RSs in the set for Tx beam recovery and identifies one or more best RSs greater than a corresponding threshold. When the WTRU identifies the one or more best Tx RSs, the WTRU transmits a PRACH associated with the one or more best Tx RSs. Lastly, the WTRU receives a confirmation (e. g. , by receiving a PDCCH via a CORESET / SS associated with the BFR set). Additional aspects features and / or advantages may become apparent from the detailed description of embodiments which follow.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein:

[0013] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0014] FIG. 1 B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0015] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0016] FIG. 1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0017] FIG. 2 is a block diagram representing an example of Hybrid beamforming;

[0018] FIG. 3 is a block diagram showing impact of beams for WTRU measurement / positioning and rotation of a WTRU;

[0019] FIG. 4 is a flow diagram illustrating a method for dynamic determination of beam failure recovery (BFR) mode according to certain embodiments; and

[0020] FIG. 5 is a flow diagram illustrating a method for dynamic determination of BFR using multiple BFR sets according to various embodiments.DETAILED DESCRIPTION

[0021] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users.The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 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), singlecarrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform Spread OFDM (ZT-UW-DFT-S- OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0022] As shown in FIG. 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (ON) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though itwill be appreciated 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 transmit and / or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0023] The communications systems 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 the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (NR) NodeB, 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.

[0024] 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), relay nodes, and the like. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensedand unlicensed spectrum A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one 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 transmit and / or receive signals in desired spatial directions.

[0025] 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).

[0026] More specifically, as noted above, the communications 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, and the like. 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), which may establish the air interface 116 using wideband CDMA (WCDMA). 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).

[0027] 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), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0028] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using NR.

[0029] 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 implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g , an eNB and a gNB).

[0030] 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), and the like.

[0031] The base station 114b in FIG 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g, for use by drones), a roadway, 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 femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106.

[0032] 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 varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc, and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and / or the CN 106 may 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 be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0033] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or the other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide 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), user datagram protocol (UDP) and / or the internet protocol (IP) in the TCP / IP internet protocol suite. The networks 112 may include wired and / or wireless communications 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.

[0034] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g, the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1 A may be configured to communicate with the base station 114a, which may employ a cellularbased radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0035] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include 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, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0036] 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 in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0037] The transmit / receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0038] Although the transmit / receive element 122 is depicted in FIG. 1 B 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.

[0039] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit / receive element 122 and to demodulate the signals that are received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0040] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit) The processor 118 may also output user datato 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 the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and 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).

[0041] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control the 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, and the like.

[0042] 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 over the air interface 116 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment

[0043] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and / or Augmented Reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors. The sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor and the like.

[0044] 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 particular subframes for both the UL (e.g., for transmission) and DL (e.g., for reception) may be concurrent and / or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In anembodiment, 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 particular subframes for either the UL (e g., for transmission) or the DL (e g., for reception)).

[0045] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to 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 ON 106.

[0046] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-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 eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a.

[0047] Each of the eNode-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 the UL and / or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0048] The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0049] The MME 162 may be connected to each of the eNode-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, and the like. 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

[0050] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the 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 user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0051] 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.

[0052] 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 communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers.

[0053] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0054] In representative embodiments, the other network 112 may be a WLAN.

[0055] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic in to and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA The traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. The peer-to- peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad-hoc” mode of communication.

[0056] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example in 802.11 systems. For CSMA / CA, the STAs (e.g., every 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.

[0057] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0058] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels The 40 MHz, and / or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0059] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control / Machine- Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g. , only support for) certain and / or limited bandwidths The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0060] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802 11 n, 802.11ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest 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, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.

[0061] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, theavailable frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0062] FIG. 1 D is a system diagram illustrating the RAN 104 and the GN 106 according to an embodiment. As noted above, the RAN 104 may employ an 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.

[0063] 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, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit 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 unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0064] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0065] 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 the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with / connect to gNBs 180a, 180b, 180c while also communicating with / connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non- standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, 102c.

[0066] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support of network slicing, DC, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0067] The CN 106 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0068] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (NAS) signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and the like 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.

[0069] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0070] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The 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, and the like.

[0071] 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 serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0072] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0073] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or in an operator network environment. For example, the one or more emulation devices may perform the one or more, 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. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network The emulation device may be directly coupled to another device for purposes of testing and / or performing testing using over-the-air wireless communications.

[0074] The one or more emulation devices may perform the one or more, including all, functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0075] In Rel-15, New Radio (NR) has introduced radio access technology (RAT) in frequency range 2 (FR2), where FR2 denotes the frequency range of 24.25 - 52.6 GHz One of key challenge of FR2 is higher propagation loss. Since propagation loss increases as carrier frequency increases, FR2 experiences the higher propagation loss. In order to overcome the higher propagation loss, efficient usage of highly directional beamformed transmission and reception is desirable.

[0076] Beamforming gain can be achieved by adding or subtracting one signal from another signal. Since more beamforming gain can be achieve as more signals are added or subtracted, utilization of large number of antenna elements are essential for the highly directional beamformed transmission. Controlling signal addition or signal subtraction can be done by controlling phases of antenna elements.

[0077] Beamforming methods can be categorized into three types (i.e, analog beamforming, digital beamforming and hybrid beamforming) based on the phase controlling types. While the digital beamforming controls a phase of a signal by applying digital precoder, the analog beamforming controls the phase of the signal through phase shifters. Generally, the digital beamforming provides good flexibility (e.g, applying different phases for different frequency resource blocks), but requires more complex implementation. In contrast to the digital beamforming, the analog beamforming provides relatively simple implementation, but has limitations (e.g., same analog beam for entire frequency resources). Given the situation, hybrid beamforming is a good architecture to achieve large beamforming gain with reasonable implementation complexity. The hybrid beamforming provides enough flexibility with reasonable implementation complexity by combining the analog beamforming and the digital beamforming.

[0078] Referring to FIG. 2, an example of a hybrid beamforming architecture 200 is shown. Hybrid beamforming architecture 200 may include a digital beamforming circuit 210 and an analog beamforming circuit 220. Since width of a beam, i e, beam width, decreases as beamforming gain increases, the beam can only cover a limited area. Therefore, the base station and the WTRU need to utilize multiple beams to cover the entire cell. For example, broadcast signals such as synchronization signal blocks (SSBs) can be transmitted along all directions (e.g, via beam sweeping) to cover the entire cell. For unicast transmission between the base station and the WTRU, procedures to optimize the beam direction to the WTRU are provided through beam management. The beam management includes selection and maintenance of the beam direction for unicast transmission (including control channel and data channel) between the base station and the WTRU

[0079] Beam management procedures can be categorized into beam determination, beam measurement and reporting, beam switching, beam indication, and beam recovery. In beam determination, the base station and the WTRU find a beam direction to ensure a reasonably stable radio link quality for the unicast control and data channel transmission. Once a link is established, the WTRU measures the link quality of multiple transmission (TX) and reception (RX) beam pairs and reports the measurement results to the base station.

[0080] Additionally, WTRU mobility, orientation, and channel blockage can alter the radio link quality of TX and RX beam pairs. When the quality of the current beam pair degrades, the base station and the WTRU can switch to another beam pair with better radio link quality. To accomplish this, the base station and WTRU can monitor the quality of the current beam pair along with some other beam pairs and perform switching when necessary. When the base station assigns a TX beam to the WTRU, via DL control signaling, the beam indication procedure is used. Beam recovery entails a recovery procedure when a link between the base station and the WTRU can no longer be maintained.

[0081] Traditionally, a WTRU decides its own reception beam based on indicated TCI states from the base station, e g., gNB. However, for AI / ML based beam prediction, a concept of beam pair prediction and indication was proposed. The beam pair prediction estimates not only qualities of gNB Tx beams but also qualities of a pair of a gNB Tx beam and a WTRU Rx beam. As the beam pair prediction considers both Tx beams and Rx beams, performance of the beam pair prediction is expected to be higher than the beam prediction. However, beam prediction may be more reliable in some cases such as WTRU rotation, WTRU movement and / or maximum permissible exposure (MPE) limits set by regulatory authorities, which limit the amount of electromagnetic radiation of which radio frequency signals may safely impact humans.

[0082] Referring to FIG. 3, an example network environment 300 illustrates beamforming effects related to WTRU rotation. As shown base station determine measurements or predictions to transmit a beam, i.e., DL Tx beam 312, based on a WTRU being in a first position 320. Similarly, the WTRU in the first position 320 may use a determined / predicted DL Rx beam 322 to receive DL Tx beam 314. However, when WTRU is rotated and / or moved to second position 325 during actual use, DL Tx beam 312 from gNB 310 and the WTRU DL Rx beam 322 may no longer correspond (this is shown graphically in FIG. 3 by respective DL Tx beam 314 and DL Rx beam 327 not corresponding) Embodiments disclosed herein may address how a WTRU decides a beam management mode between a Tx beam mode and a beam pair mode for beam indication, beam failure recovery and / or beam reporting.

[0083] Common terminology for various embodiments will now be described. Hereinafter, ‘a’ and ‘an’ and similar phrases are to be interpreted as ‘one or more’ and ‘at least one ’ Similarly, any term which ends with the suffix ‘(s)’ may be interpreted as ‘one or more’ and ‘at least one.’ The term ‘may’ can be interpreted as ‘may, for example.’ A symbol 7’ (e.g., forward slash) may be used herein to represent ‘and / or,’ where for example, ‘A / B’ may imply 'A and / or B’

[0084] Artificial intelligence (Al) may be broadly defined as the behavior exhibited by machines. Such behavior may e.g., mimic cognitive functions to sense, reason, adapt and act.

[0085] Machine learning (ML) may refer to a type of algorithms that solve a problem based on learning through experience (‘data’), without explicitly being programmed (‘configuring set of rules’). Machine learning can be considered as a subset of Al. Different machine learning paradigms may be envisioned based on the nature of data or feedback available to the learning algorithm. In an example, a supervised learning approach may involve learning a function that maps input to an output based on labeled training examples, wherein each training example may be a pair including an input and the corresponding output In another example, an unsupervised learning approach may involve detecting patterns in the data with no pre-existing labels. In another example, a reinforcement learning approach may involve performing a sequence of actions in an environment to maximize a cumulative reward. In some solutions, it is possible to apply machine learning algorithms using a combination or interpolation of the above-mentioned example approaches. For example, a semi-supervised learning approach may use a combination of a small amount of labeled data with a large amount of unlabeled data during training. In this regard semi-supervised learning falls between unsupervisedlearning (with no labeled training data) and supervised learning (with only labeled training data). As used herein, AI / ML may mean one or more categories of Al.

[0086] Deep learning refers to class of machine learning algorithms that employ artificial neural networks (specifically deep neural networks (DNNs)) which are loosely inspired from biological systems. The DNNs are a special class of machine learning models inspired by the human brain wherein the input is linearly transformed and passed-through a non-linear activation function multiple times. DNNs typically include multiple layers where each layer includes a linear transformation and a given non-linear activation functions. The DNNs can be trained using the training data via a back-propagation algorithm. Recently, DNNs have shown state-of-the-art performance in a variety of domains, e.g., speech, vision, natural language, etc., and for various machine learning settings such as supervised, un-supervised, and semi-supervised. The term AIML based methods / processing may refer to realization of behaviors and / or conformance to requirements by learning based on data, without explicit configuration of a sequence of steps of actions. Such methods may enable learning complex behaviors which might be difficult to specify and / or implement when using legacy methods.

[0087] Definition of Beam. A WTRU may transmit or receive a physical channel or reference signal according to at least one spatial domain filter. The term “beam” may be used to refer to a spatial domain filter. The WTRU may transmit (Tx) a physical channel or signal using the same spatial domain filter as the spatial domain filter used for receiving (Rx) a reference signal (RS) (such as channel state information (CSI)-RS) or a synchronization signal (SS) block. The WTRU transmission may be referred to as “target”, and the received RS or SS block may be referred to as “reference” or “source.” In such cases, the WTRU may be said to transmit the target physical channel or signal according to a spatial relation with a reference to such RS or SS block.

[0088] The WTRU may transmit a first physical channel or signal according to the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel or signal. The first and second transmissions may be referred to as “target” and “reference” (or “source”), respectively. In such case, the WTRU may be said to transmit the first (target) physical channel or signal according to a spatial relation with a reference to the second (reference) physical channel or signal.

[0089] A spatial relation may be implicit, configured by radio resource control (RRC) or signaled by a medium access layer (MAC) control element (CE) or in downlink control information (DCI). For example, a WTRU may implicitly transmit a PUSCH and demodulation reference signal (DM-RS) of the PUSCH according to the same spatial domain filter as a sounding reference signal (SRS) indicated by a SRS resource indicator (SRI) indicated in DCI or configured by RRC In another example, a spatial relation may be configured by RRC for a SRI or signaled by a MAC CE for a PUCCH. Such spatial relation may also be referred to as a “beam indication.”

[0090] The WTRU may receive a first (target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (reference) downlink channel or signal. For example, such association may exist between a physical channel such as PDCCH or PDSCH and its respective DM-RS.At least when the first and second signals are reference signals, such association may exist when the WTRU is configured with a quasi-colocation (QCL) assumption type D between corresponding antenna ports. Such association may be configured as a transmission configuration indicator (TCI) state. In an example, a WTRU may be indicated an association between a channel state information reference signal (CSI-RS) or synchronization signal block (SSB) and a DM-RS by an index to a set of TCI states configured by RRC and / or signaled by MAC CE. Such indication may also be referred to as a “beam indication.”

[0091] Hereafter, a transmission and reception point (TRP) may be interchangeably used with one or more of transmission point (TP), reception point (RP), radio remote head (RRH), distributed antenna (DA), base station (BS), a sector (of a BS), and a cell (e.g., a geographical cell area served by a BS), but still consistent with the embodiments herein. Hereafter, a Multi-TRP may be interchangeably used with one or more of MTRP, M-TRP, and multiple TRPs, but still consistent with the disclosed embodiments.

[0092] In various embodiments, a WTRU may report a subset of channel state information (CSI) components, where CSI components may correspond to at least a CSI-RS resource indicator (CRI), a SSB resource indicator (SSBRI), an indication of a panel used for reception at the WTRU (such as a panel identity or group identity), measurements such as Layer 1 reference signal received power (L1-RSRP), L1 signal interference to noise ratio (L1-SINR) taken from a SSB or CSI-RS (e.g. cri-RSRP, cri-SINR, ssb-lndex-RSRP, ssb-lndex-SINR), and other channel state information such as at least rank indicator (Rl), channel quality indicator (CQI), precoding matrix indicator (PMI), Layer Index (LI), and / or the like.

[0093] In example embodiments, a WTRU may receive a synchronization signal / physical broadcast channel (SS / PBCH) block. The SS / PBCH block (SSB) may include a primary synchronization signal (PSS), secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The WTRU may monitor, receive, or attempt to decode a SSB during initial access, initial synchronization, radio link monitoring (RLM), cell search, cell switching, and so forth.

[0094] In certain embodiments, a WTRU may measure and report the channel state information (CSI), wherein the CSI for each connection mode may include or be configured with one or more of following:

[0095] CSI Report Configuration, including one or more of the following:-CSI report quantity, e.g., Channel Quality Indicator (CQI), Rank Indicator (Rl), Precoding Matrix Indicator (PMI), CSI-RS Resource Indicator (CRI), Layer Indicator (LI), etc.-CSI report type, e.g., aperiodic, semi persistent, periodic.-CSI report codebook configuration, e g., Type I, Type II, Type II port selection, etc.-CSI report frequency.

[0096] CSI-RS Resource Set, including one or more of the following CSI Resource settings: -Non-zero-power (NZP)-CSI-RS Resource for channel measurement. -NZP-CSI-RS Resource for interference measurement.-CSI-lnterference Measurement (IM) Resource for interference measurement.

[0097] NZP CSI-RS Resources, including one or more of the following:-NZP CSI-RS Resource ID.-Periodicity and offset.-QCL Info and TCI -state.-Resource mapping, e.g., number of ports, density, code division multiplexing (CDM) type, etc.

[0098] A WTRU may indicate, determine, or be configured with one or more reference signals (RSs). The WTRU may monitor, receive, and measure one or more parameters based on the respective reference signals. For example, one or more of the following non-limiting example parameters that may be included in reference signal(s) measurements (other parameters may also be included):

[0099] Secondary synchronization reference signal received power (SS-RSRP) may be measured based on the synchronization signals (e.g , demodulation reference signal (DMRS) in the physical broadcast channel (PBCH) or secondary synchronization signal (SSS)). It may be defined as the linear average over the power contribution of the resource elements (REs) that carry the respective synchronization signal. In measuring the RSRP, power scaling for the reference signals may be required. In case a SS-RSRP is used for L1-RSRP, the measurement may be accomplished based on CSI reference signals in addition to the synchronization signals.

[0100] CSI-RSRP may be measured based on the linear average over the power contribution of the resource elements (REs) that carry the respective CSI-RS. The CSI-RSRP measurement may be configured within measurement resources for the configured CSI-RS occasions.

[0101] SS signal-to-noise and interference ration (SS-SINR) may be measured based on the synchronization signals (e.g., DMRS in PBCH or SSS). It may be defined as the linear average over the power contribution of the resource elements (RE) that carry the respective synchronization signal divided by the linear average of the noise and interference power contribution. In case SS-SINR is used for L1-SINR, the noise and interference power measurement may be accomplished based on resources configured by higher layers.

[0102] CSI-SINR may be measured based on the linear average over the power contribution of the resource elements (RE) that carry the respective CSI-RS divided by the linear average of the noise and interference power contribution. In case CSI-SINR is used for L1-SINR, the noise and interference power measurement may be accomplished based on resources configured by higher layers. Otherwise, the noise and interference power may be measured based on the resources that carry the respective CSI-RS.

[0103] Received signal strength indicator (RSSI) may be measured based on the average of the total power contribution in configured OFDM symbols and bandwidth. The power contribution may be received from different resources (e.g., co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc.).

[0104] Cross-Layer Interference received signal strength indicator (CLI-RSSI) may be measured based on the average of the total power contribution in configured OFDM symbols of the configured time and frequencyresources. The power contribution may be received from different resources (e.g., cross-layer interference, cochannel serving and non-serving cells, adjacent channel interference, thermal noise, etc.).

[0105] Sounding reference signals RSRP (SRS-RSRP) may be measured based on the linear average over the power contribution of the resource elements (REs) that carry the respective SRS.

[0106] Secondary synchronization signal reference signal received quality (SS-RSRQ) may be measured based on measurements on the reference signal received power (SS-RSRP) and received signal strength indicator (RSSI). In an example, the SS-RSRQ may be calculated as the ratio of NxSS-RSRP I NR carrier RSSI, where N may be determined based on the number of resource blocks that are in the corresponding NR carrier RSSI measurement bandwidth. As such, the measurements to be used in the numerator and denominator may be over the same set of resource blocks.

[0107] CSI reference signal received quality (CSI-RSRQ) may be measured based on measurements on the CSI reference signal received power (CSI-RSRP) and received signal strength indicator (RSSI). In an example, the SS-RSRQ may be calculated as the ratio of NxCSI-RSRP / CSI-RSSI, where N may be determined based on the number of resource blocks that are in the corresponding CSI-RSSI measurement bandwidth. As such, the measurements to be used in the numerator and denominator may be over the same set of resource blocks.

[0108] Beam / CSI Report Configurations. A CSI report configuration (e.g , CSI-ReportConfigs) may be associated with a single bandwidth part (BWP) (e.g., indicated by BWP-ld), wherein one or more of the following parameters are configured:-CSI-RS resources and / or CSI-RS resource sets for channel and interference measurement;-CSI-RS report configuration type including the periodic, semi-persistent, and aperiodic;-CSI-RS transmission periodicity for periodic and semi-persistent CSI reports;-CSI-RS transmission slot offset for periodic, semi-persistent and aperiodic CSI reports;-CSI-RS transmission slot offset list for semi-persistent and aperiodic CSI reports;-Time restrictions for channel and interference measurements;-Report frequency band configuration (wideband / subband CQI, PMI, and so forth);-Thresholds and modes of calculations for the reporting quantities (CQI, RSRP, SINR, LI, Rl, etc.);-Codebook configuration;-Group based beam reporting;-CQI table;-Subband size;-Non-PMI port indication; and / or-Port Index.

[0109] CSI-RS Resource Configuration. A CSI-RS Resource Set (e.g., NZP-CSI-RS-ResourceSet) may include one or more of CSI-RS resources (e.g , NZP-CSI-RS-Resource and CSI-ResourceConfig), wherein aWTRU may be configured with one or more of the following in a CSI-RS Resource: (i) CSI-RS periodicity and slot offset for periodic and semi-persistent CSI-RS resources; (ii) CSI-RS resource mapping to define the number of CSI-RS ports, density, code division multiplexing (CDM)-type, OFDM symbol, and subcarrier occupancy; (iii) the bandwidth part (BWP) to which the configured CSI-RS is allocated; (iv) the reference to the TCI-State including the QCL source RS(s) and the corresponding QCL type(s).

[0110] RS resource set Configuration. A WTRU may be configured with one or more RS resource sets where a RS resource set configuration may include one or more of: a RS resource set ID, one or more RS resources for the RS resource set, a Repetition (i.e., on or off), aperiodic triggering offset (e.g., one of 0-6 slots), and tracking reference signal (TRS) info (e.g., true or not).

[0111] RS resource Configuration. A WTRU may be configured with one or more RS resources, where a RS resource configuration may include one or more of: RS resource ID, resource mapping (e.g., REs in a physical resource block (PRB)), power control offset (e.g., one value of -8, .... 15), power control offset with SS (e g., -3 dB, 0 dB, 3 dB, 6 dB), scrambling ID, periodicity and offset and QCL information (e.g., based on a TCI state).

[0112] Property of a grant or assignment. In the following, a property of a grant or assignment may include of at least one of the following:-A frequency allocation;-An aspect of time allocation, such as a duration;-A priority;-A modulation and coding scheme;-A transport block size;-A number of spatial layers;-A number of transport blocks;-A TCI state, CRI or SRI;-A 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 scheduling (configured) assignment;-A configured grant index or a semi-persistent assignment index;-A periodicity of a configured grant or assignment;-A channel access priority class (CAPC); and / or-Any parameter provided in a DCI, by MAC or by RRC for the scheduling the grant or assignment.

[0113] In the following, an indication by DCI may consist of at least one of: (i) an explicit indication by a DCI field or by radio network temporary identifier (RNTI) used to mask or scramble the cyclic redundancy check (CRC) of the DCI; or (ii) an implicit indication by a property such as DCI format, DCI size, CORESET or searchspace, Aggregation Level, first resource element of the received DCI (e.g., index of first Control Channel Element (CCE)), where the mapping between the property and the value may be signaled by RRC or MAC. Receiving or monitoring for a DCI with, or using, a RNTI may mean that the CRC of the DCI is masked or scrambled with the RNTI.

[0114] Hereafter, the following terms may be used and still be consistent with the disclosed embodiments. A signal may be interchangeably used with one or more of: sounding reference signal (SRS), channel state information - reference signal (CSI-RS), demodulation reference signal (DM-RS), phase tracking reference signal (PT-RS), and / or synchronization signal block (SSB). A channel may be interchangeably used with one or more of: physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH), physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), and / or physical random access channel (PRACH). A signal, channel, and message (e g., as in DL or UL signal, channel, and / or message) may be used interchangeably. Similarly, RS may be interchangeably used with one or more of RS resource, RS resource set, RS port and RS port group RS may also be interchangeably used with one or more of SSB, CSI-RS, SRS, and DM-RS, tracking reference signal (TRS), positioning reference signal (PRS), and / or PTRS. A time instance, slot, symbol, and subframe may be used interchangeably. The terms SSB, SS / PBCH block, PSS, SSS, PBCH, and master information block (MIB) may be used interchangeably.

[0115] The disclosed solutions for beam resources prediction may be used for beam resources belonging to a single or multiple cells as well as single or multiple TRPs. CSI reporting may be interchangeably used with CSI measurement, beam reporting and beam measurement. Furthermore, RS resource set may be interchangeably used with a beam group, but still consistent with the disclosed embodiments.

[0116] The quasi-colocation (QCL) types may take one of the following values:Type A: {Doppler shift, Doppler spread, average delay, delay spread}; Type B: {Doppler shift, Doppler spread}; Type C: {Doppler shift, average delay}; and Type D: {Spatial Rx parameter}.

[0117] Configuration of beam pairs. In various embodiments, a WTRU may be configured / indicated with: (i) an association between a first type of TCI states; and / or (ii) a TCI state including a first QCL type. For example, in the association between a first type of TCI states (e.g., including QCL Type D and / or DL Tx beam ID) and a second type of TCI states (e.g., including another QCL Type and / or DL Rx beam ID), the WTRU may receive a set of first type TCI states (e.g., with one or more of QCL Type A / B / C configuration and QCL Type D configuration) and a set of second type TCI states (e.g., with one or more of QCL Type A / B / C, QCL Type D and other QCL Type (e.g., QCL Type E)). In an example of the TCI state including a first QCL type (e g., QCL Type D and / or DL Tx beam ID) and / or a second QCL type (e.g., including another QCL Type and / or DL Rx beam ID), the WTRU may be configured with one or more TCI states and each TCI state may be configured with the first QCL type and / or the second QCL type. The WTRU may determine a QCL type between the first QCL type and the second QCL type to determine a spatial Rx relation for receiving one or more DL channels and / or signals. Hereafter, DL Rx beam ID may be interchangeably used with DL beam pair ID, but still consistent with the disclosure.

[0118] Embodiments for dynamic determination of beam failure recovery (BFR) mode are now described.

[0119] Dynamic determination of beam failure recovery (BFR) mode and configuration for separate beam failure recovery procedures are disclosed. In certain embodiments, a WTRU may support different beam failure recovery procedures. For example, a first beam failure recovery mode (e.g., an other QCL type recovery mode and / or DL Rx beam recovery mode) may be used for recovering the other QCL type or DL Rx beams, while a second beam recovery mode (e.g., QCL Type D recovery mode and / or DL Tx beam recovery mode) may be used for recovering QCL Type D.

[0120] Referring to FIG. 4, a method 400 for dynamic determination of BFR mode is shown. The WTRU receives 405 a configuration for beam failure recovery (BFR) including one or more of the following: (i) a set of beam failure detection (BFD) RSs; (ii) a set of new candidate beam (NCB) RSs for QCL Type D (e.g., with multiple Tx beams); (iii) a set of new NCB RSs for the other QCL Type (e.g., with a best beam and repetition); (iv) a set of RSs for determining a BFR mode; and / or (v) corresponding thresholds for one or more of MPE, WTRU rotation and WTRU movement. As discussed in more detail below, an independent set of RSs for determining the BFR mode is optional as BFD RSs, NCB RSs or other RSs may be used for determining the BFR mode.

[0121] The WTRU measures 410 received RS(s) associated with the configured set of RSs for determining a BFR mode and determines a mode of operation for BFR based on measured parameters of MPE, WTRU rotation and / or WTRU movement. If 415, the measured MPE, WTRU rotation and / or WTRU movement are smaller than the corresponding configured thresholds, the WTRU determines 420 a BFR mode for the other QCL Type. If 415, one or more of the measured MPE, WTRU rotation and / or WTRU movement is larger than the corresponding configured thresholds, the WTRU determines 425 a BFR mode for QCL Type D.

[0122] The WTRU next monitors 430 RSs associated with the configured set of BFD RSs for beam failure detection. When the WTRU detects the number of beam failure instances are greater than a corresponding threshold, the WTRU starts beam failure recovery procedure based on the determined BFR mode. If 440, the BFR mode for other QCL Type is determined (e.g., at step 420), the WTRU measures 445 RS(s) associated with the configured set of NCB RSs for other QCL Type and identifies one or more IDs for the other QCL Type based on a measured parameter such as RSRP exceeding a corresponding threshold. If 450, the WTRU identifies one or more IDs for the other QCL Type exceeding the threshold, the WTRU transmits 455 a physical random access channel (PRACH) using resources or parameters configured as being associated with the one or more best measured RSs for the other QCL Type. If 450, the WTRU does not identify the one or more best IDs for the other QCL Type (e.g., within a timer or a counter), the WTRU starts a BFR procedure for QCL Type D.

[0123] If the BFR for QCL Type D is determined (e.g., at step 425) or the BFR for the other QCL Type is failed (e.g., at step 450), the WTRU measures 460 NCB RS(s) associated with the configured set of NCB RSs for QCL Type D and identifies one or more best RSs for QCL Type D > a corresponding threshold. The WTRUtransmits 465 a PRACH indicating a candidate beam(s) associated with the one or more best RSs for QCL Type D. Lastly, the WTRU receives 470 a confirmation of the new beam from the gNB (e.g., by receiving a PDCCH via a CORESET / SS associated with the BFR).

[0124] In a first example, one or more of the following configurations may be used for beam failure recovery. The WTRU may receive a configuration of one or more parameters for determining a mode for beam failure recovery. The one or more parameters may be one or more of WTRU rotation, WTRU movement, MPE and others. The WTRU may also receive a configuration of one or more thresholds for determining a mode for beam failure recovery, where each threshold may be associated with the one or more parameters. In one example, the one or more parameters may be predefined or indicated for each threshold. One or more dedicated RS resources / resource sets for determining the BFR mode by measuring configured parameters may also be included in a WTRU configuration. Alternatively, beam failure detection (BFD) RSs and / or new candidate beam (NCB) RSs may be used for measuring configured parameters In another solution, RS resources for measuring the configured parameters may be determined based on the configuration. For example, if dedicated RS resources are configured for BFR mode determination, the WTRU may measure the configured parameters by measuring one or more received RSs associated with the dedicated configured RS resources for BFR mode determination. If dedicated BFR mode determination RS resources are not configured, the WTRU may measure the configured parameters by measuring BFD RSs and / or NCB RSs.

[0125] The WTRU may be configured with a set of beam failure detection (BFD) RSs (e.g., q0). For example, an RS set may be configured for both BFR modes of operation. In one embodiment, the configuration of the one or more sets of BFD-RS may be based on an implicit configuration. For example, if the WTRU does not receive explicit configuration for the BFD-RS set, the WTRU may determine the BFD-RS set based on one or more RSs with QCL Type-D in configured TCI states for PDCCH reception.

[0126] The WTRU may be configured with one or more sets of new candidate beam (NCB) RSs (e.g., q1 L), wherein qr imay be the set of new candidate beam RSs associated with an / th beam failure recovery mode. For example, a first NCB RS set (q1 0) may be associated with a first beam failure recovery mode (e.g., an other QCL type recovery mode and / or DL Rx beam recovery mode) and a second NCB RS set (q±) may be associated with a second beam failure recovery mode (e.g., QCL Type D recovery mode and / or DL Tx beam recovery mode). In one example, the first NCB RS set may be configured with an identical TCI state and / or identical QCL Type D RSs. In a solution, repetition of RSs may be used with an identical TCI state and / or an identical QCL Type D RSs (e.g., for identifying a best other QCL Type and / or DL Rx beam).

[0127] In one solution, the second NCB RS set may be configured with different TCI states and / or different QCL Type D RSs The second NCB RS set may be configured with an identical other QCL RSs (e.g., for identifying a best QCL Type D and / or DL Tx beam). In one example, the NCB-RSs in all NCB-RS sets may be associated with one uplink resource. In another solution, each NCB-RS in the set may be associated with one or more uplink resources (e.g., PRACH, PUCCH, PUSCH, and / or SRS).

[0128] The WTRU may also be configured with one or more sets of uplink resources (S for new candidate beam indication, wherein S’; is a set of uplink resources to indicate a new candidate beam for one of the beam failure recovery modes For example, Somay be associated with the first beam failure recovery mode and Srmay be associated with the second beam failure recovery mode.

[0129] The WTRU may be further configured with one or more sets of search spaces (C for receiving one or more confirmation random access responses of BFR, wherein C, is a set of search spaces to receive random access response for BFR for one of the beam failure recovery modes. For example, Comay be associated with the first beam failure recovery mode and C, may be associated with the second beam failure recovery mode.

[0130] The WTRU may be configured with one or more counters and one or more maximum numbers, i.e., thresholds, of the one or more counters. The counters may be one or more of following: (i) BFD counters and thresholds for the BFD counters for beam failure detection instances; (ii) beam reporting counters and thresholds for the beam reporting counters; and / or (iii) preamble power ramping counter and thresholds for preamble power ramping counter used for random access. In one embodiment, if a set of counters (e.g., one or more of BFD counter, beam reporting counter and / or preamble power ramping counter) and thresholds are configured, the set of counters and thresholds may be used for both BFR modes. If multiple sets of counters (e g., one or more of BFD counter, beam reporting counter and preamble power ramping counter) and thresholds are configured, a first set of counters and thresholds may be used for the first BFR mode and a second set of counters and thresholds may be used for the second BFR mode. In one example, the number of configured counters and number of configured thresholds for each set may be the same.

[0131] The WTRU may be further configured with one or more timers. The one or more timers may be one or more of beam failure instance (BFI) timers, BFD timers, and / or BFR timers. In one example, if a set of timers (e g., one or more of BFI timer, BFD timer and BFR timer) is configured, the set of timers may be used for both BFR modes. If multiple sets of timers are configured, a first set of timers may be used for the first recovery mode and a second set of timers may be used for the second recovery mode.

[0132] According to one embodiment, the WTRU may determine one or more new candidate beam sets (Qnew.i) from oneconfigured NCB RS set. Each new candidate beam may be associated with a different beam failure recovery mode, wherein qneW:iis determined as a new candidate beam (or beam index) for one of beam failure recovery modes. For example, a first new candidate beam (qneW;i) may be selected from the new candidate beam RS set associated with the first beam failure recovery mode (e.g., RSs configured with a TCI state including an other QCL Type) and a second new candidate beam (qneWi2) may be selected from the new candidate beam RS set associated with the second beam failure recovery mode (e.g., RS configured with a TCI state including QCL Type D without an other QCL Type).

[0133] BFR mode determination. In one embodiment, the WTRU may measure the one or more RS resources and determine a beam failure recovery mode based on the measurement. For example, the WTRU may determine a first beam failure recovery mode (e.g., an other QCL type recovery mode and / or DL Rx beamrecovery mode) if one or more of the following conditions are satisfied: (i) if the measured WTRU rotation is less than a corresponding threshold; (ii) if the measured WTRU movement is less than a corresponding threshold; and / or (iii) if the measured MPE is less than a corresponding threshold. Otherwise, the WTRU determines a second beam failure recovery mode (e.g., QCL Type D recovery mode and / or DL Tx beam recovery mode).

[0134] Beam failure detection. In certain embodiments, the WTRU may determine a beam failure instance (BFI) if a number of failed BFD RSs is greater than a configured / predefined threshold (e.g., all configured BFD RSs fail). Failure of a BFD RS may be defined based on application of a same set of measurement parameters and thresholds or application of different sets of measurement parameters and thresholds. For application of a same set of measurement parameters and thresholds, in one example, the WTRU may determine beam failure if a measured parameter (e.g., hypothetical PDCCH BLER or RSRP) of the RS is lower than a threshold. For application of different sets of measurement parameters and thresholds, in one example, the WTRU may apply different sets of parameter and thresholds based on a determined BFR mode For example, for the first BFR mode, the WTRU may determine beam failure for a BFD RS if a first type of measured parameter (e.g., hypothetical PDCCH BLER) of the RS is lower than a first threshold. For the second BFR mode, the WTRU may determine beam failure for the BFD RS if a second type of predicted parameter (e.g., RSRP) of the RS is lower than the second threshold.

[0135] According to some embodiments, the WTRU may apply a beam failure recovery procedure if a number of detected beam failure instances within a time window is greater than a corresponding threshold. In one solution, the WTRU may initiate a procedure for new beam selection and determine one or more RSs from the one or more NCB RSs.

[0136] New beam selection procedure. According to one embodiment, the new beam selection procedure may be based on the determined BFR mode. For example, if the WTRU determines the first BFR mode, the WTRU may initiate a new beam selection procedure for the first BFR mode based on the first NCB RS set (e.g., selecting one or more RSs from the first NCB RS set). If the WTRU determines the second BFR mode, the WTRU may initiate a new beam selection procedure for the second BFR mode based on the second NCB RS set (e.g., selecting one or more RSs from the second NCB RS set). Measurement parameters and thresholds for new beam selection may be based on using a same set of measurement parameters and thresholds or application of different sets of measurement parameters and thresholds. In using a same set of measurement parameters and thresholds, in one solution, the WTRU may determine one or more RSs based on a same set of measurement parameters and thresholds. For example, the WTRU may measure a same type of parameter (e g., RSRP) for the one or more NCB RS sets. If the measured parameter of NCB RSs in the one or more NCB RS sets is higher than a threshold, the WTRU may determine the NCB RSs (e.g., with top qualities based on the measured parameter).

[0137] In application of different sets of measurement parameters and thresholds, in one solution, the WTRU may apply different sets of parameter and thresholds based on a determined BFR mode For example,the WTRU may measure different types of measurement parameters (e.g , measured RSRP or predicted RSRP) based on a determined BFR mode If the measured parameter of the RS is higher than a corresponding threshold, the WTRU may determine one or more RSs based on the determined measured parameters (e.g., with top qualities based on the measured parameter). For example, for the first BFR mode, the WTRU may determine one or more RSs from the one or more NCB RSs based on a first set of measurement parameters (e g., hypothetical BLER) and thresholds. For the second BFR mode, the WTRU may determine one or more RSs from the one or more NCB RSs based on a second set of measurement parameters (e.g, measured RSRP) and thresholds.

[0138] Indication of newly selected beams. In one embodiment, the WTRU may transmit one or more uplink channels and / or signals for beam failure incident indication and / or new candidate beam indication. The uplink channels and / or signals may be one or more of MAC-CE, RRC, PRACH (e.g, RACH msg 1 , msg 3, msg A), PUSCH, PUCCH, PUSCH DM-RS, scheduling request (SR), SRS, and / or an SR-like signal, wherein the SR-like signal may be an uplink channel which may be reserved periodically. The uplink resources may be based on using a same set of uplink resource configurations or application of different sets of measurement parameters and thresholds. In embodiments using a same set of uplink resource configurations, the WTRU may transmit one or more uplink channels / signals based on a same set of uplink resource configurations. For example, regardless of the BFR mode, the WTRU may transmit the one or more uplink signals / channels (e.g, an UL sequence and / or an UL resource) associated with the selected QCL Type D (e.g, Tx beam) and / or the other QCL type (e.g, Rx beam with UL RS and / or DL Rx beam ID) in the same set of uplink resource configurations.

[0139] For embodiments, applying different sets of measurement parameters and thresholds, in one solution, the WTRU may transmit one or more uplink channels based on different sets of uplink resource configurations. For example, based on a determined BFR mode, the WTRU may transmit the one or more uplink signals / channels (e.g, an UL sequence and / or an UL resource) associated with the selected QCL Type D (e.g, Tx beam) and / or the other QCL type (e.g, Rx beam with UL RS and / orDL Rx beam ID) in an associated set of uplink resource configurations. By way of example, for the first BFR mode, the WTRU may transmit one or more uplink signals / channels (e.g, an UL sequence and / or an UL resource) associated with the selected QCL Type D (e.g, Tx beam) and / or the other QCL type (e.g, Rx beam with UL RS and / or DL Rx beam ID) in a first set of configured uplink resources. For the second BFR mode, the WTRU may transmit one or more uplink signals / channels (e.g, an UL sequence and / or an UL resource) associated with the selected QCL Type D (e.g, Tx beam) in a second set of configured uplink resources.

[0140] Confirmation on the WTRU indication. In certain embodiments, the WTRU may receive one or more downlink channels and / or signals for a confirmation for the beam failure incident indication and / or the new candidate beam indication (e.g, from a gNB). The downlink channels and / or signals may be one or more of PDCCH, PDSCH, MAC CE, RRC, PDCCH DM-RS, PDSCH DM-RS, CSI-RS, SSB, TRS (e.g, CSI-RS for tracking), PT-RS, etc. The downlink resources may be based on using a same set of downlink resourceconfigurations or application of different sets of measurement parameters and thresholds. In using a same set of downlink resource configurations, the WTRU may receive one or more downlink channels based on a same set of downlink resource configurations. For example, regardless of a determined BFR mode type, the WTRU may receive the one or more downlink channels using the same set of configuration downlink resources (e.g., with a same CORESET / Search Space / time and frequency resources). In one example, the same set of configured DL resources may be used only if one set of DL resources is configured.

[0141] In applying different sets of measurement parameters and thresholds, the WTRU may receive one or more downlink channels based on different sets of configured downlink resources. For example, based on a determined BFR mode, the WTRU may determine a different downlink resource configuration for receiving the one or more downlink channels. For example, for the first BFR mode, the WTRU may receive one or more downlink channels based on a first set of configured downlink resources (e.g., with a first set of CORESET / Search Space / time and frequency resources). For the second BFR mode, the WTRU may receive one or more downlink channels based on a second set of configured downlink resources (e.g., with a second set of CORESET / Search Space / time and frequency resources). In one example, the different sets of DL resources in the configuration may be used if a dedicated set of DL resources is configured for each BFR mode.

[0142] Failure of a BFR procedure. According to certain embodiments, the WTRU may determine the BFR procedure is not successful based on one or more of WTRU indication on new candidate beams and gNB confirmation. The WTRU may determine the BFR procedure as unsuccessful based on failure of identification of new candidate beams or failure to receive a confirmation. In failure of identification of new candidate beams, if the WTRU does not find one or more resources for the other QCL Type and / or QCL Type D, the WTRU may determine the BFR procedure is not successful. In certain embodiments, a timer or a counter may be used. For example, if the WTRU does not find the one or more resources before expiration of the timer, the WTRU may determine the BFR procedure is unsuccessful. In another example, if a number of WTRU trial / failure for identifying the one or more resources is greater than a corresponding threshold, the WTRU may determine the BFR procedure is unsuccessful.

[0143] In a case of failure to receive a confirmation (e.g., from a gNB), if the WTRU does not receive one or more DL channels / signals for the confirmation, the WTRU may determine the BFR procedure is unsuccessful. In one example embodiment, a timer or a counter may be used. For example, if the WTRU does not receive the one or more DL channels / signals before expiration of the timer, the WTRU may determine the BFR procedure is not successful. Alternatively, or in addition, if a number of WTRU trial / failures for receiving the one or more confirmation DL channels / signals is greater than a corresponding threshold, the WTRU may determine the BFR procedure is unsuccessful.

[0144] According to some embodiments, the WTRU may initiate a procedure if the WTRU determines the BFR mode is not successful. In one solution, the WTRU may determine the procedure based on a determined BFR mode. For example, if the determined BFR mode is the first BFR mode and the BFR procedure for the first BFR mode failed, the WTRU may initiate a BFR procedure for the second BFR mode. If the determinedBFR mode is the second BFR mode and the BFR procedure for the second BFR mode failed, the WTRU may initiate a contention based RACH procedure.

[0145] Embodiments for dynamic determination of beam failure recovery mode based on multiple sets are now described. Referring to FIG 5, an example method 500 for dynamic determination of beam failure recovery mode based on multiple BFR sets is shown. The WTRU receives 505 a configuration of a set of RSs for determining a BFR mode, thresholds for one or more of MPE, WTRU rotation and WTRU movement and two or more beam failure recovery (BFR) sets for TX beam recovery and Rx beam recovery and each BFR set includes one or more of: (i) a set of beam failure detection (BFD) RSs; (ii) a set of new candidate beam (NCB) RSs; (iii) one or more Search Spaces / CORESETs; and / or (iv) one or more UL resources (e g., PRACH resources).

[0146] The WTRU measures 510 received RS(s) associated with the set of RSs for determining the BFR mode and determines parameter values for MPE, WTRU rotation and / or WTRU movement based on the measurements. If 515, the MPE, WTRU rotation and / or WTRU movement values are less than the corresponding configured thresholds, the WTRU activates 520 the BFR set for the other QCL Type. If one or more of the determined values for MPE, WTRU rotation and / or WTRU movement are greater than the corresponding configured thresholds, the WTRU activates the BFR set for QCL Type D.

[0147] If the BFR set for the other QCL Type is activated 520, the WTRU monitors 525 the set of BFD RSs in the BFR set for the other QCL Type to detect beam failure If the WTRU detects beam failure instances > a corresponding threshold, then the WTRU starts a beam failure recovery procedure by the WTRU measuring 535 the set of NCB RSs in the BFR set for the other QCL Type and identifying one or more best Rx IDs > a corresponding threshold. If 540, the WTRU identifies the one or more best Rx IDs, the UE transmits 545 a PRACH associated with the one or more best Rx IDs. If 550, the BFR procedure for the other QCL Type is successful, the WTRU uses 555 the DL Rx beams indicated in the PRACH and / or confirmed by the gNB.

[0148] If 540, the WTRU does not identify the one or more best Rx IDs (e g., within a timer or a counter) or if 550 the BFR procedure for the other QCL Type is unsuccessful, the WTRU starts a BFR procedure based on the BFR set for QCL Type D.

[0149] If the BFR set for QCL Type D is activated 525, or if the BFR procedure for the other QCL Type fails (at step 550) the WTRU monitors / measures 560 the set of BFD RSs in the BFR set for QCL Type D If the WTRU detects beam failure instance > a corresponding threshold, then the WTRU starts a beam failure recovery procedure (e.g., only for Tx beam recovery activation). The WTRU measures 565 the set of NCB RSs in the set for Tx beam recovery and identifies one or more best RSs > a corresponding threshold. If the WTRU identifies the one or more best Tx RSs, the WTRU transmits 570 a PRACH indicating the identified one or more best Tx RSs. If 575 the BFR for QCL Type D is successful, e.g., the WTRU receives a confirmation (e g., by receiving a PDCCH via a CORESET / SS associated with the BFR set), the WTRU uses 555 the indicated Tx beam(s); otherwise 575, the BFR process is stopped 580 or restarted.

[0150] According to various embodiments, a WTRU may select a BFR set out of multiple (e.g., two) sets to perform BFR. Each BFR set may associate with a mode of BFR (e.g., BFR for QCL Type D or BFR for another QCL type). The WTRU may determine a mode of BFR based on WTRU determination, or gNB indication, or gNB configuration and may select a BFR set based on the determined mode of BFR. To this end, a WTRU may perform one or combination of the following procedures

[0151] WTRU configuration for BFR set and BFR mode determination. In certain embodiments, the WTRU may be configured or receive configuration of one or more thresholds associated with one or more measured parameters to determine the mode of BFR. The measured parameters may include MPE, WTRU rotation, WTRU movement, and so forth. The WTRU may determine the mode of BFR based on one or more measured parameters and the thresholds associated with the measured parameters. For example, the WTRU may be configured or receive a threshold for MPE. The WTRU may measure the MPE and if the measured MPE is smaller than the corresponding threshold, the WTRU may select first mode of operation for BFR (e.g , BFR for the other QCL Type) If the measured MPE is larger than the corresponding threshold, the WTRU may select a second mode of operation for BFR (e.g., BFR for QCL Type D). As used herein, the first mode of operation for BFR and BFR for the other QCL Type may be interchangeably used, but still consistent with the disclosed embodiments. Further, the second mode of operation for BFR and BFR for QCL Type D may be interchangeably used, but still consistent with the disclosed embodiments. In another example, the WTRU may be configured or receive thresholds for MPE and WTRU rotation. The WTRU may measure the MPE and WTRU rotation and if the measured MPE and rotation are smaller than the corresponding thresholds, the WTRU may select BFR mode for the other QCL Type. If the measured MPE and WTRU rotation are larger than the corresponding thresholds, the WTRU may select BFR mode for QCL Type D

[0152] In this embodiment, the WTRU may receive multiple BFR sets (e.g., two BFR sets) for transmit beam recovery and receive beam recovery. Each BFR set may include one or more of: (i) a set of beam failure detection (BFD) RSs; (ii) a set of new candidate beam (NCB) RSs; (iii) one or more search spaces or CORESETs; (iv) one or more UL resources (e.g., PRACH resources); (v) one or more counters and associated maximum counter value; (vi) one or more timers; and / or (vii) one or more beam quality thresholds.

[0153] A BFR set may include a set of beam failure detection (BFD) RSs. In an example, the WTRU may be configured with a set of BFD RSs by the gNB via explicit indication (e.g., via RRC signaling, MAC-CE indication). In another example, the WTRU may determine a set of BFD RSs based on activated TCI states for PDCCH reception. To this end, the WTRU may determine the BFD RSs to be RSs indicated by TCI state for respective CORESETs that the WTRU uses for monitoring the PDCCH. If there is more than one RS index in a TCI state, the WTRU may select an RS configured with QCL Type set to 'Type D' for the corresponding TCI states as a BFD RS.

[0154] The BFR set may include a set of new candidate beam (NCB) RSs. In an example, the WTRU may receive the configuration of a RS resource set as NCB RSs (e.g., via RRC signaling or MAC-CE indication). In an example, the WTRU may receive the configuration of a RS resource set as potential NCB RSs along with athreshold on beam measurement (e g., L1-RSRP threshold) via RRC signaling or MAC-CE indication. The WTRU may measure / estimate / predict the configured beam measurement (e.g., L1-RSRP) of the potential NCB RSs and select a subset of RSs with beam measurement larger than the configured beam measurement threshold (e.g., L1-RSRP threshold). The WTRU may indicate a selected set of RSs out of potential NCB RSs to the gNB via UL signaling (e.g., as a bit map in a MAC-CE). In an example, a set of NCB RSs for the first BFR mode (e g., for other QCL type) may be configured with a repetition and / or a same QCL type D. In an example, a set of NCB RSs for the second BFR mode (e.g., for QCL Type D) may be configured with different QCL type Ds (e.g., for each NCB RS) and / or without repetition.

[0155] The BFR set may include one or more search spaces or CORESETs. For example, the WTRU may be configured with one or more search spaces or CORESETs to receive confirmation indication from the gNB for beam failure indication and selected candidate beam indication. A BFR set may include one or more UL resources (e.g., PRACH resources). The WTRU may receive the association between each UL resource (e.g., PRACH resources) and NCB RSs. For example, each NCB RS associates with one PRACH resource in a PRACH resource set The BRF set may further include one or more counters and associated maximum counter value; for example, a beam failure instances (BFI) counter and the maximum BFI counter value. One or more timers may be included, for example, a beam failure detection timer and a beam failure recovery timer. One or more beam quality thresholds may also be included, for example, a hypothetical PDCCH BLER threshold for BFD RSs, or for example, a L1-RSRP threshold for NCB RSs.

[0156] WTRU determining BFR Set based on Model of Operation. In one embodiment, the WTRU may measure one or more configured parameters via a set of configured RSs by the gNB (e.g., via RRC signaling, MAC-CE indication) for determining the BFR mode. For example, a WTRU may measure one or more of MPE, WTRU rotation, and WTRU movement, and so forth. If one or more of the measured MPE, WTRU rotation, and WTRU movement is smaller than the corresponding thresholds configured by the gNB (e.g., via RRC signaling, MAC-CE indication), the WTRU may select the BFR mode for the other QCL Type. In another example, if one or more of the measured MPE, WTRU rotation and WTRU movement is larger than the corresponding thresholds configured by the gNB (e.g., via RRC signaling, MAC-CE indication), the WTRU may select the BFR mode for QCL Type D. Once a BFR mode is determined, the WTRU may indicate the selected BFR mode to the gNB (e.g., via PUCCH, MAC-CE or by transmitting a preconfigured PRACH resource associates with the selected BFR mode)

[0157] In another embodiment, the WTRU may determine the BFR mode based on one or more of the CSI reporting modes and beam indication mode. For example, if the WTRU determined or indicated or configured to perform beam indication with DL Tx beam mode, the WTRU may select the BFR mode for QCL Type D. In another example, if the WTRU determined, or indicated, or configured to perform beam reporting with DL Tx beam pair mode, the WTRU may select the BFR mode for the other QCL Type. In yet another embodiment, the WTRU may determine the BFR mode based on gNB indication (e.g., via RRC signaling, MAC-CE indication, DCI indication).

[0158] Based on the BFR mode determined by the WTRU or configured or indicated by the gNB, the WTRU may select a BFR set. For example, consider a WTRU configured with a first BFR set of the first BFR mode (i.e., BFR for the other QCL Type) and a second BFR set of second BFR mode (BFR for QCL Type D). If the WTRU selected the BFR for the other QCL Type, WTRU may select the first BFR set (BFR set for the other QCL Type). If the WTRU selected the BFR for QCL Type D, the WTRU may select the second BFR set (BFR set for QCL Type D). Hereafter, the first BFR set may be interchangeably used with BFR set for the other QCL Type, but still consistent with the embodiments disclosed. Further, hereafter, the second BFR set may be interchangeably used with BFR set for QCL Type D, but still consistent with the embodiments disclosed. Once a BFR set is selected, the WTRU may indicate the selected BFR set to the gNB (e.g, via PUCCH, MAC-CE or by transmitting a preconfigured PRACH resource associates with the selected BFR set).

[0159] WTRU performing BFD and BFR based on the selection BFR Set. In certain embodiments, the WTRU may monitor one or more BFD RSs associated with the selected BFR Set. If the WTRU detects, a number of beam failure instances, higher than the maximum beam failure instance (BFI) counter before the beam failure detection counter expires, the WTRU may determine a beam failure. Once a beam failure is determined, the WTRU may start a BFR procedure based on the determined BFR mode and selected the BFR set. To this end, the WTRU may follow one or any combination of the following procedures.

[0160] If the BFR for the other QCL Type is determined, the WTRU may measure the beam quality (e.g., L1-RSRP) of the set of NCB RSs of the BFR set for the other QCL Type. If the beam quality of at least one of the NCB RS is larger than the corresponding beam quality threshold (e.g., L1-RSRP threshold for NCB RSs), the WTRU may select an NCB RS meeting beam quality threshold (e g., NCB RS with the highest L1-RSRP) as the new beam The WTRU may transmit a PRACH resource of the BFR set for the other QCL Type associated with the selected NCB RS to the gNB indicating the selected new beam(s). The WTRU may monitor for a confirmation indication for new beam indication (e.g., via a PDCCH) from the gNB (e.g., via a preconfigured CORESET or search space associated with the BFR set for the other QCL type) in a monitoring time window.

[0161] If a confirmation indication is received from the gNB, the WTRU may start using the selected new beam for future signal transmission and reception. If a confirmation indication is not received from the gNB within the monitoring window, the WTRU may: (1) perform BFR with the BFR set for QCL Type D; or (2) retransmit the PRACH resource associated with the selected NCB RS of the BFR set for the other QCL Type with additional power, and monitor for a confirmation indication from the gNB. The WTRU may repeat this process a number of times preconfigured by the gNB (e.g., via RRC signaling) If all the successive attempts become unsuccessful, the WTRU may determine to process the BFR with the BFR set for QCL Type D.

[0162] If the BFR for the other QCL type is determined, but the WTRU determines that the beam quality measurement (e.g., L1-RSRP) of all the NBC RSs of BFR set for the other QCL Type is lower than the corresponding beam quality threshold (e.g., L1-RSRP threshold for NCB RSs), the WTRU may determine to process the BFR with the BFR set for QCL Type D.

[0163] If the BFRfor QCL Type D is determined, the WTRU may measure the beam quality (e.g , L1 -RSRP) of the set of NCB RSs of the BFR set for QCL Type D. If the beam quality of at least one of the NCB RS is larger than the corresponding beam quality threshold (e.g., L1-RSRP threshold for NCB RSs), the WTRU may select an NCB RS meeting a beam quality threshold (e.g., NCB RS with the highest L1-RSRP) as the new beam. The WTRU may determine and transmits a PRACH resource of BFR set QCL Type D associated with the selected NCB RS to the gNB. The WTRU may monitor for a confirmation indication for new beam indication via the PRACH (e.g , via a PDCCH) from the gNB (e.g, via a preconfigured CORESET or search space associated with BFR set for QCL Type D) in a monitoring time window.

[0164] If a confirmation indication is received from the gNB, the WTRU may select the determined new beam associated with the NCB RS of the BFR set for QCL Type D as the beam resource for future signal transmission and reception If a confirmation indication is not received from the gNB, the WTRU may: (1) retransmit the PRACH resource associated with the selected NCB RS of the BFR set for QCL Type D with additional power and monitors for a confirmation indication from the gNB (the WTRU may repeat this process a number of times preconfigured by the gNB (e.g, via RRC signaling)); or (2) declare a radio link failure (RLF) and process a contention based random access which may include cell reselection.

[0165] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magnetooptical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMSWhat is Claimed:

1. A method for a wireless transmit and receive unit (WTRU), the method comprising: receiving configuration information for beam failure recovery (BFR) including a set of beam failure detection (BFD) reference signals (RSs), a set of new candidate beam (NCB) RSs for quasi-colocation (QCL) Type D, a set of NCB RSs for an other QCL Type, a set of RSs to determine a BFR mode and corresponding thresholds for WTRU rotation, WTRU movement and maximum permissible exposure (MPE); measuring one or more received RSs associated with the configured set of RSs to determine the BFR mode and, based on the measured one or more received RSs, calculating of one or more of MPE, WTRU rotation and WTRU movement, wherein if the calculated MPE, WTRU rotation and WTRU movement are less than or equal to the configured corresponding thresholds, determining the BFR mode as for the other QCL Type, and otherwise, determining the BFR mode as for QCL Type D; monitoring received RSs associated with the configured set of BFD RSs for beam failure detection; and based upon the monitoring, upon detecting a number of beam failure instances (BFI) greater than a threshold, starting a BFR procedure corresponding to the determined BFR mode.

2. The method of claim 1, wherein the determined BFR mode is for the other QCL Type and the BFR procedure comprises: measuring one or more RSs associated with the configured set of NCB RSs for the other QCL Type; identifying one or more RS IDs for the other QCL Type greater than a corresponding threshold; and transmitting a physical random access channel (PRACH) associated with at least one of the identified one or more RS IDs for the other QCL Type.

3. The method of claim 1, wherein the determined BFR mode is for the QCL Type D or no RS IDs for the other QCL Type are identified greater than a corresponding threshold, the BFR procedure comprises: measuring one or more RSs associated with the configured set of NCB RSs for QCL Type D, identifying one or more RS IDs for QCL Type D greater than a corresponding threshold; and transmitting the PRACH associated with at least one of the identified one or more RS IDs for QCL Type D.

4. The method of any of claims 1 or 3, further comprising: receiving a confirmation of the BFR procedure by receiving a physical downlink control channel (PDCCH) via a control resource set (CORESET) or a search space (SS) associated with the determined BFR mode.

5. The method of claim 4, wherein the CORESET or SS associated with the determined BFR mode is received in the configuration information.

6. A wireless transmit receive unit (WTRU) comprising: a transceiver and a processor communicatively coupled to the transceiver, the transceiver and processor configured to: receive configuration information for beam failure recovery (BFR) including a set of beam failure detection (BFD) reference signals (RSs), a set of new candidate beam (NCB) RSs for quasi-colocation (QCL) Type D, a set of NCB RSs for an other QCL Type, a set of RSs to determine a BFR mode and corresponding thresholds for WTRU rotation, WTRU movement and maximum permissible exposure (MPE); measure one or more received RSs associated with the configured set of RSs to determine the BFR mode and, based on the measured one or more received RSs, calculating of one or more of MPE, WTRU rotation and WTRU movement, wherein if the calculated MPE, WTRU rotation and WTRU movement are less than or equal to the configured corresponding thresholds, determine the BFR mode as for the other QCL Type, and otherwise, determine the BFR mode as for QCL Type D; monitor received RSs associated with the configured set of BFD RSs for beam failure detection; and based upon the monitoring, upon detecting a number of beam failure instances (BFI) greater than a threshold, starting a BFR procedure corresponding to the determined BFR mode.

7. The WTRU of claim 6, wherein the determined BFR mode is for the other QCL Type and the BFR procedure comprises the transceiver and processor configured to: measure one or more RSs associated with the configured set of NCB RSs for the other QCL Type; identify one or more RS IDs for the other QCL Type greater than a corresponding threshold; and transmit a physical random access channel (PRACH) associated with at least one of the identified one or more RS IDs for the other QCL Type.

8. The WTRU of claim 6, wherein the determined BFR mode is for QCL Type D or no RS IDs for the other QCL Type are identified greater than a corresponding threshold, the BFR procedure comprises the transceiver and processor configured to: measure one or more RSs associated with the configured set of NCB RSs for QCL Type D, identify one or more RS IDs for QCL Type D greater than a corresponding threshold; and transmit the PRACH associated with at least one of the identified one or more RS IDs for QCL Type D.

9. The WTRU of any of claims 6 to 8, wherein the transceiver and processor are further configured to: receive a confirmation of the corresponding BFR procedure by receiving a physical downlink control channel (PDCCH) via a control resource set (CORESET) or a search space (SS) associated with the determined BFR mode.

10. The WTRU of claim 9, wherein the CORESET or SS associated with the determined BFR mode in the received configuration information.

11. A method for a wireless transmit and receive unit (WTRU), the method comprising: receiving configuration information of a set of reference signals (RSs) for determining a beam failure recovery (BFR) mode, corresponding thresholds for one or more of WTRU rotation, WTRU movement and maximum permissible exposure (MPE) and two or more BFR sets including a first BFR set for quasicolocation (QCL) Type D and a second BFR set for an other QCL Type, wherein each respective BFR set includes one or more of a set of beam failure detection (BFD) RSs, a set of new candidate beam (NCB) RSs, one or more search spaces (SSs) or control resource sets (CORESETs) and one or more physical random access channel (PRACH) resources; measuring one or more received RSs associated with the configured set of RSs for determining the BFR mode and, based on the measured one or more received RSs, calculating of one or more of MPE, WTRU rotation and WTRU movement, wherein if the calculated MPE, WTRU rotation and WTRU movement are less than or equal to the configured corresponding thresholds, activating the second BFR set for the other QCL Type, and otherwise, activating the first BFR setfor QCL Type D; monitoring received RSs associated with the configured BFD RSs of the activated first BFR set or second BFR set; and based upon the monitoring, upon detecting a number of beam failure instances (BFI) greater than a threshold, starting a BFR procedure corresponding to the activated first BFR set or second BFR set.

12. The method of claim 11 , wherein the second BFR set for the other QCL Type is activated and the BFR procedure comprises: measuring one or more RSs associated with the configured set of NCB RSs of the activated second BFR set for the other QCL Type; identifying one or more RS IDs for the other QCL Type greater than a corresponding threshold and selecting one or more corresponding RX IDs; and transmitting a physical random access channel (PRACH) associated with the selected one or more corresponding RX IDs for the other QCL Type.

13. The method of claim 11 , wherein the first BFR set for QCL Type D is activated or no RS IDs for other QCL Type are identified greater than a corresponding threshold, the BFR procedure comprises: measuring one or more RSs associated with the configured set of NCB RSs of the activated first BFR set for QCL Type D; identifying one or more RS IDs for QCL Type D greater than a corresponding threshold and selecting one or more corresponding TX IDs; andtransmitting the PRACH associated with the selected one or more corresponding TX IDs for QCLType D.

14. The method of any of claims 11 to 13, further comprising: receiving a confirmation of the BFR procedure by receiving a physical downlink control channel (PDCCH) via the configured CORESET or SS associated with the activated first BFR set or second BFR set.

15. A wireless transmit receive unit (WTRU) comprising: a transceiver and a processor communicatively coupled to the transceiver, the transceiver and processor configured to: receive configuration information of a set of reference signals (RSs) for determining a beam failure recovery (BFR) mode, corresponding thresholds for one or more of WTRU rotation, WTRU movement and maximum permissible exposure (MPE) and two or more BFR sets including a first BFR set for quasicolocation (QCL) Type D and a second BFR set for an other QCL Type, wherein each respective BFR set includes one or more of a set of beam failure detection (BFD) RSs, a set of new candidate beam (NCB) RSs, one or more search spaces (SSs) or control resource sets (CORESETs) and one or more physical random access channel (PRACH) resources; measure one or more received RSs associated with the configured set of RSs for determining the BFR mode and, based on the measured one or more received RSs, calculate of one or more of MPE, WTRU rotation and WTRU movement, wherein if the calculated MPE, WTRU rotation and WTRU movement are less than or equal to the configured corresponding thresholds, activate the second BFR set for other QCL Type, and otherwise, activate the first BFR set for QCL Type D; monitor received RSs associated with the configured BFD RSs of the activated first BFR set or second BFR set; and based upon the monitoring, upon detecting a number of beam failure instances (BFI) greater than a threshold, starting a BFR procedure corresponding to the activated first BFR set or second BFR set.

16. The WTRU of claim 15, wherein the second BFR set for other QCL Type is activated and the BFR procedure comprises the transceiver and processor configured to: measure one or more RSs associated with the configured set of NCB RSs of the activated second BFR set for the other QCL Type; identify one or more RS IDs for other QCL Type greater than a corresponding threshold and select one or more corresponding RX IDs; and transmit a physical random access channel (PRACH) associated with the selected one or more corresponding RX IDs for the other QCL Type.

17. The WTRU of claim 15, wherein the first BFR set for QCL Type D is activated or no RS IDs for other QCL Type are identified greater than a corresponding threshold, the BFR procedure comprises the transceiver and processor configured to: measure one or more RSs associated with the configured set of NCB RSs of the activated first BFR set for QCL Type D, identify one or more RS IDs for QCL Type D greater than a corresponding threshold and select one or more corresponding TX IDs; and transmit the PRACH associated with the selected one or more corresponding TX IDs for QCL Type D.

18. The WTRU of any of claims 15 to 17, wherein the transceiver and processor are further configured to: receive a confirmation of the BFR procedure by receiving a physical downlink control channel(PDCCH) via the configured CORESET or SS associated with the activated first BFR set or second BFR set.

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