Methods on BFR enhancement based on traffic in ai / ML systems

Abstract

A wireless transmit / receive unit (WTRU) may determine a blockage of a first beam and / or a time duration associated with the blockage of the first beam. The WTRU may postpone beam failure detection (BFD) or beam failure recovery (BFR) when an amount of data is less than a first threshold, a priority of the data is less than a second threshold, and / or the time duration associated with the determined blockage of the first beam is shorter than a third threshold. The WTRU may send a report comprising indications of the determined blockage, the time duration associated with the determined blockage, the amount of data associated with the first beam, a priority of the data associated with the first beam, that BFD or BFR is postponed, and / or that a second beam has been selected.

Description

METHODS ON BFR ENHANCEMENT BASED ON TRAFFIC IN AI / ML SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 566,436, filed on March 18, 2024, the entire contents of which are incorporated herein by reference.BACKGROUND

[0002] In radio access network (RAN) #102, RAN work item on artificial intelligence (Al) / machine learning (ML) for new radio (NR) air interface was agreed. As one of the target use-cases for AI / ML for air interface, beam management was selected. This technology may be the foundation in improving performance and / or complexity in conventional beam management aspects. Such aspects may include beam prediction in time, and / or spatial domain for overhead and / or latency reduction, and / or beam selection accuracy improvement, etc.SUMMARY

[0003] A wireless transmit / receive unit (WTRU) may determine a blockage of a first beam and / or a time duration associated with the blockage of the first beam. The WTRU may determine to postpone beam failure detection (BFD) or beam failure recovery (BFR) when an amount of data associated with the first beam is less than a first threshold, a priority of the data associated with the first beam is less than a second threshold, and / or the time duration associated with the determined blockage of the first beam is shorter than a third threshold. The WTRU may send, to a network, a first report comprising one or more of an indication of the determined blockage, an indication of the time duration associated with the determined blockage of the first beam, an indication of the amount of data associated with the first beam, a priority of the data associated with the first beam, an indication that BFD or BFR is postponed, and / or an indication that a second beam has been selected.

[0004] The WTRU may determine the blockage of the first beam via an artificial intelligence or machine learning (AI / ML) model. The WTRU may determine that the blockage still exists after the time duration expires via the AI / ML model. The WTRU may perform BFR based on the determination that the blockage still exists after the time duration expires.

[0005] The WTRU may determine that the blockage does not exist after the time duration expires. The WTRU may send, to the network, a second report based on the determination that the blockage does not exist after the time duration expires. The second report may comprise an indication that the blockage doesnot exist. The WTRU may select the second beam based on a determination that the second beam has beam measurement and / or prediction value greater than the first beam.

[0006] The first report may comprise one or more of a start time of the time duration or an end time of the time duration. The WTRU may determine the amount of data associated with the first beam prior to a start time of the blockage. The WTRU may receive an indication from the network. The indication may comprise a confirmation or a rejection to postpone BFD and / or BFR. The WTRU may receive, from the network, an indication of a postponement period. The indication of postponement period may be based on the indication comprising a confirmation to postpone BFD and / or BFR. The postponement period may indicate how long to postpone BFD and / or BFR. The WTRU may perform BFR based on the indication from the network comprising the rejection to postpone BFD and / or BFR.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0008] 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.

[0009] 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. 1 A according to an embodiment.

[0010] FIG. 1 D 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. 1 A according to an embodiment.

[0011] FIG. 2 is a diagram of an example of blockage for a user equipment (UE) in mobility status.

[0012] FIG. 3 depicts an example of skipping the transmission of a subset of SSBs.

[0013] FIG. 4 depicts a scenario wherein beam #1 is temporarily blocked and a WTRU is moving towards the center of beam #1 .

[0014] FIG. 5 depicts a scenario wherein beam #1 is temporarily blocked and a UE is moving towards the center of beam #2.DETAILED DESCRIPTION

[0015] 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 accesssystem 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), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0016] As shown in FIG. 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will 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” and / or a “ST A”, 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 WTRU. Further, any description herein that is described with reference to a UE may be equally applicable to a WTRU (or vice versa). For example, a WTRU may be configured to perform any of the processes or procedures described herein as being performed by a UE (or vice versa).

[0017] 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 / 115, the I nternet 110, and / or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a gNB, a 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.

[0018] The base station 114a may be part of the RAN 104 / 113, 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, etc. 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 licensed and 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.

[0019] 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).

[0020] 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 / 113 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 115 / 116 / 117 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 UL Packet Access (HSUPA).

[0021] I n 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 airinterface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0022] I n 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 New Radio (NR).

[0023] 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., a eNB and a gNB).

[0024] 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.

[0025] The base station 114b in FIG. 1 A 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 / 115.

[0026] The RAN 104 / 113 may be in communication with the CN 106 / 115, 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 / 115 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 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may be utilizing a NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0027] The CN 106 / 115 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 / 113 or a different RAT.

[0028] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0029] 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.

[0030] 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) circuits, 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. 1B 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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 outputuser data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as 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).

[0035] 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.

[0036] 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 locationdetermination method while remaining consistent with an embodiment.

[0037] 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, and / or a humidity sensor.

[0038] 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 downlink (e.g., for reception) may be concurrent and / or simultaneous. The full duplex radio may include an interference management unit 139 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 an embodiment, the WRTU 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 downlink (e.g., for reception)).

[0039] 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 CN 106.

[0040] 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.

[0041] 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.

[0042] The CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of 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.

[0043] 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 mayprovide 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Although the WTRU is described in FIGS. 1 A-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.

[0048] In representative embodiments, the other network 112 may be a WLAN.

[0049] 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 an 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 anddestination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11 e DLS or an 802.11 z 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.

[0050] 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 via signaling. 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 in 802.11 systems. For CSMA / CA, the STAs (e.g., every ST A), 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.

[0051] 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.

[0052] 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 non-contiguous 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).

[0053] 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 802.11 ah relative to those used in 802.11 n, 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-TVWSspectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control / Machine- Type Communications, 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).

[0054] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11 n, 802.11 ac, 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, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0055] 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, the available 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.

[0056] FIG. 1 D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0057] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 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 totransmit 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).

[0058] 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 varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0059] 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.

[0060] 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, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control planeinformation towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0061] The CN 115 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 each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0062] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 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 PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of 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 machine type communication (MTC) access, and / or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 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.

[0063] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 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 WTRU IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0064] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 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 forwardingpackets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0065] The CN 115 may facilitate communications with other networks. For example, the CN 115 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 115 and the PSTN 108. In addition, the CN 115 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 Data Network (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.

[0066] In view of Figures 1A-1 D, and the corresponding description of Figures 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-ab, 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.

[0067] 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 may performing testing using over-the-air wireless communications.

[0068] 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 / orwireless 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.

[0069] Herein, ‘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)’ is to be interpreted as ‘one or more’ and ‘at least one’. The term ‘may’ is to be interpreted as ‘may, for example’. A symbol ‘I’ e.g., forward slash) may be used herein to represent ‘and / or’, where for example, ‘A / B’ may imply ‘A and / or B’. Herein, the terms prediction and estimation may be used interchangeably, but still consistent with this invention. Herein, the terms candidate cell, neighbor cell, and target cell may be used interchangeably, but still consistent with this invention. Herein, the terms source cell, current cell, and serving cell may be used interchangeably, but still consistent with this invention. Herein, the terms LTM command, LTM cell switch, LTM cell switch command, and cell switch command may be used interchangeably, but still consistent with this invention.

[0070] Artificial intelligence (Al) may be broadly defined as the behavior exhibited by machines. Such behavior may, for example, mimic cognitive functions to sense, reason, adapt, and / or act.

[0071] Machine learning may (ML) refer to type of algorithms that solve a problem based on learning through experience (e.g., data), without explicitly being programmed (e.g., configuring set of rules). ML may be considered as a subset of Al. Different ML paradigms may be envisioned based on the nature of data or feedback available to the learning algorithm. For example, a supervised learning approach may involve learning a function that maps input to an output based on a labeled training example. Each training example may be a pair consisting of input and / or the corresponding output. For example, an unsupervised learning approach may involve detecting patterns in the data with no pre-existing labels. A reinforcement learning approach may involve performing sequence of actions in an environment to maximize the cumulative reward.

[0072] A combination and / or interpolation of the above-mentioned approaches may apply machine learning algorithms. Semi-supervised learning approach may use a combination of a small amount of labeled data with a large amount of unlabeled data during training. Semi-supervised learning may fall between unsupervised learning (with no labeled training data) and supervised learning (with only labeled training data).

[0073] Deep learning refers to class of machine learning algorithms that employ artificial neural networks loosely inspired from biological systems. The Deep Neural Networks (DNNs) are a special class of machine learning models inspired by human brain functions. In DNNs, an input may be linearly transformed and / or pass-through non-linear activation function multiple times. DNNs may typically consist of multiple layerswhere each layer may consist of linear transformations and / or a given non-linear activation functions. The DNNs may be trained using the training data via back-propagation algorithm. Recently, DNNs have shown state-of-the-art performance in variety of domains, e.g., speech, vision, natural language, and / or various machine learning settings supervised, un-supervised, and / or semi-supervised. The term AI / ML based methods and / or processing may refer to realization of behaviors and / or conformance to requirements by learning based on data, without explicit configuration of sequence of steps of actions. Such methods may enable learning complex behaviors which may be difficult to specify and / or implement when using legacy methods.

[0074] Herein, an AI / ML model may be referred to as an implementation of an AI / ML based method comprised of model parameters and / or the model structure. For example, a DNN-based AI / ML model may comprise the model parameters (e.g., weights and / or biases) and / or the model structure, such as the types and / or sizes of each layer of the DNN (e.g., dense layers, and / or convolutional layers, etc.).

[0075] A user equipment (UE), also known as a wireless transmit receive unit (WTRU), may transmit and / or receive a physical channel and / or reference signal (RS) according to at least one spatial domain filter. The term “beam” may refer to a spatial domain filter. The WTRU may transmit a physical channel and / or signal using the same spatial domain filter as the spatial domain filter used for receiving a reference signal (RS) (e.g., a channel state information RS (CSI-RS)) or a synchronization signal (SS) block (SSB). The WTRU transmission may be referred to as “target”, and / or the received RS and / or SSB may be referred to as “reference” and / or “source”. In such case, the WTRU may be said to transmit the target physical channel and / or signal according to a spatial relation with a reference to such RS and / or SSB.

[0076] The WTRU may transmit a first physical channel and / or signal according to the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel and / 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 and / or signal according to a spatial relation with a reference to the second (reference) physical channel and / or signal.

[0077] A spatial relation may be implicit, configured by radio resource control (RRC) and / or signaled by a medium access control (MAC) control element (CE) or downlink control information (DCI). For example, a WTRU may implicitly transmit physical uplink shared channel (PUSCH) and / or DM-RS of PUSCH according to the same spatial domain filter as an SRS indicated by an SRI indicated in DCI and / or configured by RRC. The RRC may configure a spatial relation for an SRS resource indicator (SRI) orsignaled by MAC CE for a physical uplink control channel (PUCCH). Such spatial relation may also be referred to as a “beam indication.”

[0078] The WTRU may receive a first downlink channel and / or signal (e.g., target) according to the same spatial domain filter or spatial reception parameter as a second downlink channel and / or signal (e.g., reference). For example, such association may exist between a physical channel such as physical downlink control channel (PDCCH) or physical downlink shared channel (PDSCH) and / or 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. A WTRU may be indicated an association between a CSI-RS or 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”.

[0079] Herein, a beam resource may consist of a TCI state, CSI-RS, a DL RS, a SSB for DL, a sounding reference signal (SRS) resource, an UL RS, and / or TCI state for UL. A beam resource may be identified by a beam indication.

[0080] A WTRU may use, receive and / or be configured with one or more sets of reference signals per bandwidth part (BWP) for monitoring and / or detecting the beam failure detection. For example, the term qO may be used for the beam failure detection set. In another example, the terms qO, 0 and / or qO, 1 may be used as the beam failure detection sets. The beam failure detections sets (e.g., set qO, q0,0, and / or qO, 1 ) may include one or more RSs, wherein the RSs may be CSI-RS resource configuration indexes and / or SSB and / or physical broadcast channel (PBCH) block indexes. The RSs included in beam failure detection RS sets may be the same as the RS configured, used, and / or received for radio link monitoring (RLM).

[0081] If a WTRU is not provided and / or configured with beam failure detection RS sets for a BWP (e.g., set qO, q0,0, or qO, 1 ), the WTRU may determine the respective RS sets. For example, the WTRU may determine the RS signals to be included in a beam failure detection RS set for a BWP based on the periodic CSI-RS resource configuration indexes. The WTRU may use these indexes for monitoring PDCCH in the respective CORESETs as indicated by TCI-state.

[0082] The WTRU may measure the reference signals included in beam failure detection RS sets and / or estimate radio link quality accordingly. The WTRU may use one or more thresholds and / or ranges for monitoring and / or estimating the radio link quality. For example, out-of-sync threshold (e.g., Q_out) and / or in-sync threshold (e.g., QJn) may be used for estimating the quality of the radio link and / or respectivebeam. The terms Q_out and QJn may be used to represent one or more attributes and parameters and the respective values.

[0083] The threshold Q_out may be used to determine the radio link and / or beam quality for which the signal transmission may not be reliably received, corresponding to out-of-sync block error rate (BLER_out). Alternatively, threshold Q_in may be used to determine the radio link and / or beam quality for which the signal transmission may be received reliably, corresponding to in-sync block error rate (BLERJn). The BLERjout and / or BLERJn may be explicitly determined by gNB.

[0084] In case BLERjout and / or BLERJn are not explicitly determined by gNB, they may be estimated based on one or more parameters. For example, the WTRU may use, receive, and / or be configured with PDCCH transmission parameters for performing the out-of-sync and / or in-sync evaluations. The number of control orthogonal frequency divisional multiplexing (OFDM) symbols, aggregation level, ratio of hypothetical PDCCH resource element (RE) energy to average secondary synchronization signal (SSS) RE energy, ratio of hypothetical PDCCH DMRS energy to average SSS RE energy, BWP in number of physical resource blocks (PRBs), subcarrier spacing, etc. may be used for determining the BLERjout and / or BLERJn thresholds.

[0085] PDCCH transmission parameters that may be included in evaluating the Q_out and QJn thresholds are shown in Table 1 and Table 2, respectively. The tables are a non-limiting example of the parameters that may be included in evaluating the out-of-sync and in-sync thresholds. One or more of those parameters may be included, such as the values, number of PRBs, and / or choices for each parameter. Other values, number of PRBs, and / or choices may be included.

[0086] Table 1 : PDCCH transmission parameters for out-of-sync evaluationTable 1

[0087] Table 2: PDCCH transmission parameters for in-sync evaluationTable 2

[0088] A WTRU may monitor the beam failure detection RS sets in active BWPs. The WTRU may further estimate the beam and / or radio link quality and report the out-of-sync and / or in-sync status. A WTRU may measure the radio link quality (L1-RSRP) for SSB(s) and / or CSI-RS(s) in corresponding beam failure detection RS set. The WTRU may then compare the measurement with respective thresholds to determine, indicate, and / or detect if a BFI has happened.

[0089] The WTRU may indicate, determine, and / or be configured with one or more beam failure detection (BFD) counters. As such, the WTRU may detect the beam failure by counting BFI indications. The WTRU may indicate, determine, and / or be configured with one or more of the following: a BFI_Counter: a counter that may be used for counting the number of BFIs, which is set to 0 initially and incremented per BFI detection; a BFI_Max_Count: a maximum value for the BFI_Counter that may trigger the beam failure detection; a BFD_Timer: a timer that may start with the first BFI detection. If the timer expires before the BFLCounter may reaches the BFI_Max_Count, the beam failure detection procedure is stopped.

[0090] The above parameters are non-limiting examples of the parameters that may be included in beam failure detection. One or more of those parameters may be included, and / or other parameters may be included.

[0091] If BFI counting has happened, the WTRU may start and / or restart BFD_Timer and / or add to BFI_Counter by 1. If BFLCounter reaches the BFI_Max_Count, the WTRU may initiate a beam failure recovery (BFR) procedure. Alternatively, if BFD_Timer has expired and / or BFLCounter has not reached the BFI_Max_Count, the beam failure detection procedure may be considered successfully complete.

[0092] A WTRU may determine, indicate, and / or trigger a beam failure recovery based on the beam failure detection procedure. The WTRU may indicate, determine, and / or be configured with one or more of the following: BFR_Timer: a timer that may start with BFR procedure; RSRP_Threshold: a threshold for RSRP used in BFR; candidateBeamRSList: a list of candidate beam reference signal indexes to be monitored, measured, and / or selected during the beam failure recovery; power ramping: parameters including power ramping step and / or received preamble target power, etc.; and / or random access. PRACH parameters may include preamble index, SSB per RACH occasion, random access response window, PRACH configuration index, random access occasions, and / or SSBs association mask index, etc.

[0093] The above parameters are non-limiting examples of the parameters that may be included in beam failure detection. One or more of those parameters may be included and / or other parameters may be included.

[0094] A WTRU may use / receive / or be configured with one or more sets of reference signals per BWP for monitoring, measuring, and selecting as the resources for the beam failure recovery. For example, the term q1 may be used for the beam failure recovery set. In another example, the terms q1 ,0 or q1,1 may be used as the beam failure recovery sets. The beam failure recovery sets (e.g., set q1 , q1 ,0, or q1 ,1 ) may include one or more reference signals. The reference signals may be CSI-RS resource configuration indexes and / or SS / PBCH block (SSB) indexes. The RSs included in BFR-RS sets may be based on candidateBeamRSList configured as part of BFR procedure.

[0095] A WTRU may initiate a BFR based on random-access procedure. The WTRU may configure the random-access parameters, start the BFR_Timer, and apply the power ramping parameters. The WTRU may monitor and / or measure one or more of the reference signals from the candidateBeamRSList. The WTRU may determine if at least one of the SSBs has SS-RSRP above respective RSRP_Threshold amongst the SSBs in candidateBeamRSList, or at least one of the CSI-RSs has CSI-RSRP above respective RSRP_Threshold amongst the CSI-RSs in candidateBeamRSList. The WTRU may then selectthe respective reference signal as the candidate new beam and / or random-access resource for BFR procedure. For example, the term q_new may be used to present the new selected beam / random-access resource. The WTRU may perform PRACH transmission in respective random-access resources and / or according to spatial relation with the periodic CSI-RS resource configuration or with SS / PBCH block associated and / or QCL-ed with index q_new.

[0096] Alternatively, if uplink channel resources e.g., uplink shared channel (UL-SCH)) resources are available, a WTRU may initiate a MAC-CE beam failure recovery procedure. As such, the WTRU may generate the BFR MAC-CE. The WTRU may then transmit on the respective UL channel resources.

[0097] A WTRU may determine, identify, and / or be configured with one or more CORESETs corresponding to the random-access procedure for the respective BFR. The WTRU may monitor PDCCH in a search space set for detection of a DCI format with respective cyclic redundancy check (CRC) scrambled with a radio network identifier ((RNTI), e.g., cell (C)-RNTI and / or modulation and coding scheme (MCS)-C- RNTI). The WTRU may determine the same antenna port quasi-collocation parameters as the ones associated with index q_new for monitoring the PDCCH in a search space set and / or receiving the corresponding PDSCH.

[0098] If BFR_Timer has expired and / or beam failure recovery procedure has not been accomplished successfully, the WTRU may trigger a link failure detection and follow with link failure recovery (LFR) procedures.

[0099] Herein, a TRP (e.g., transmission and reception point) 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 (e.g., of a BS), and / or a cell (e.g., a geographical cell area served by a BS). Herein, multi-TRP may be interchangeably used with one or more of multiple (M)TRP, M-TRP, and multiple TRPs.

[0100] 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 L1-RSRP, L1 -signal to noise ratio (SINR) taken from SSB and / 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), and / or Layer Index (LI), etc.

[0101] 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 physical broadcast channel (PBCH). The WTRU may monitor, receive, or attempt to decode an SSB during initial access, initial synchronization, radio link monitoring (RLM), cell search, cell switching, etc.

[0102] A WTRU may measure and report the channel state information (CSI), wherein the CSI for each connection mode may include and / or be configured with one or more of following: CSI report configuration. The CSI report configuration may include 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), and / or Layer Indicator (LI), etc.); CSI report type (e.g., aperiodic, semi persistent, and / or periodic); CSI report codebook configuration (e.g., Type I, Type II, and / or Type II port selection, etc.); and / or CSI report frequency.

[0103] CSI for each connection mode may include and / or be configured with one or more of following: CSI-RS resources, 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; and / or CSI-IM Resource for interference measurement.

[0104] CSI for each connection mode may include and / or be configured with one or more of following: NZP CSI-RS resources, including one or more of the following: NZP CSI-RS Resource ID; periodicity and / or offset; QCL Info and / or TCI-state; and / or resource mapping (e.g., number of ports, density, and / or CDM type, etc.)

[0105] A WTRU may indicate, determine, and / or be configured with one or more reference signals. The WTRU may monitor, receive, and / or measure one or more parameters based on the respective reference signals. The following parameters are non-limiting examples of the parameters that may be included in reference signal(s) measurements. One or more of these parameters may be included, and / or other parameters may be included.

[0106] Parameters may include SS-RSRP. SS reference signal received power (SS-RSRP) may be measured based on the synchronization signals (e.g., DM-RSs in PBCH or SSS). SS reference signal received power may be defined as the linear average over the power contribution of the RE that carry the respective synchronization signal. In measuring the RSRP, power scaling for the reference signals may be required. In case SS-RSRP is used for L1-RSRP, the measurement may be accomplished based on CSI reference signals in addition to the synchronization signals.

[0107] Parameters may include CSI-RSRP. CSI-RSRP may be measured based on the linear average over the power contribution of the RE that carry the respective CSI-RS. The CSI-RSRP measurement may be configured within measurement resources for the configured CSI-RS occasions.

[0108] Parameters may include SS-SINR. SS signal-to-noise and interference ration (SS-SINR) may be measured based on the synchronization signals (e.g., DMRS in PBCH and / or SSS). SS-SINR may be defined as the linear average over the power contribution of the 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 -SI NR, the noise and interference power measurement may be accomplished based on resources configured by higher layers.

[0109] Parameters may include CSI-SINR. CSI-SINR may be measured based on the linear average over the power contribution of the 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 -SI NR, 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.

[0110] Parameters may include RSSI. Received signal strength indicator (RSSI) may be measured based on the average of the total power contribution in configured OFDM symbols and / or bandwidth. The power contribution may be received from different resources (e.g., co-channel serving and / or non-serving cells, adjacent channel interference, and / or thermal noise, etc.)

[0111] Parameters may include CLI-RSSI. 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 / or frequency resources. The power contribution may be received from different resources (e.g., cross-layer interference, co-channel serving and / or non-serving cells, adjacent channel interference, and / or thermal noise, etc.).

[0112] Parameters may include SRS-RSRP. Sounding reference signals RSRP (e.g., SRS-RSRP) may be measured based on the linear average over the power contribution of the RE that carry the respective SRS.

[0113] Parameters may include SS-RSRQ. 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 (RSSI). The SS-RSRQ may be calculated as the ratio of N*SS- RSRP / NR carrier RSSI, where N may be determined based on the number of resource blocks that are inthe corresponding NR carrier RSSI measurement bandwidth. As such, the measurements to be used in the numerator and / or denominator may be over the same set of resource blocks.

[0114] Parameters may include CSI-RSRQ. CSI reference signal received quality (CSI-RSRQ) may be measured based on measurements on the reference signal received power (CSI-RSRP) and / or received signal strength (RSSI). 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 / or denominator may be over the same set of resource blocks.

[0115] A CSI report configuration e.g., CSI-ReportConfigs) may be associated with a single 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 / or aperiodic; CSI-RS transmission periodicity for periodic and semi-persistent CSI reports; CSI-RS transmission slot offset for periodic, semi-persistent and / or aperiodic CSI reports; CSI-RS transmission slot offset list for semi-persistent and / or aperiodic CSI reports; time restrictions for channel and / or interference measurements report frequency band configuration (e.g., wideband and / or subband CQI, and / or precoding matrix indicator (PMI), etc.) Thresholds and / or modes of calculations for the reporting quantities (CQI, RSRP, SINR, LI, and / or rank indicator (Rl), etc.); codebook configuration; group based beam reporting; CQI table; subband size; non-PMI port indication; and / or port index, etc.

[0116] A CSI-RS (e.g., NZP-CSI-RS-ResourceSet) may include one or more of CSI-RS resources (e.g., NZP-CSI-RS-Resource and / or CSI-ResourceConfig), wherein a WTRU may be configured with one or more of the following in a CSI-RS resource: CSI-RS periodicity and / or slot offset for periodic and / or semi- persistent CSI-RS resources; CSI-RS resource mapping to define the number of CSI-RS ports, density, CDM-type, OFDM symbol, and / or subcarrier occupancy; the bandwidth part to which the configured CSI- RS is allocated; and / or the reference to the TCI-State including the QCL source RS(s) and / or the corresponding QCL type(s).

[0117] A WTRU may be configured with one or more RS resource sets. The RS resource set configuration may include one or more of following: RS resource set ID, one or more RS resources for the RS resource set, repetition (e.g., on or off), aperiodic triggering offset (e.g., one of 0-6 slots), and / or TRS info (e.g., true or not).

[0118] A WTRU may be configured with one or more RS resources. The RS resource configuration may include one or more of following: RS resource ID; resource mapping (e.g, REs in a 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 / or offset; and / or QCL information (e.g, based on a TCI state).

[0119] A property of a grant and / or assignment may consist of at least one of the following: a frequency allocation; an aspect of time allocation, such as a duration; a priority; a modulation and / or coding scheme; a transport block size; a number of spatial layers; a number of transport blocks; a TCI state, CRI and / or SRI; a number of repetitions; whether the repetition scheme is Type A and / or Type B; whether the grant is a configured grant Type 1 , Type 2, and / or a dynamic grant; whether the assignment is a dynamic assignment and / or a semi-persistent scheduling (e.g, configured) assignment; a configured grant index and / or a semi- persistent assignment index; a periodicity of a configured grant and / or assignment; a channel access priority class (CAPC); and / or any parameter provided in a DCI, by MAC, and / or by RRC for the scheduling the grant and / or assignment.

[0120] An indication by DCI may consist of at least one of the following: an explicit indication by a DCI field or by RNTI used to mask and / or scramble the CRC of the DCI. An implicit indication by a property such as DCI format, DCI size, CORESET and / or search space, aggregation level, and / or first resource element of the received DCI (e.g, index of first control channel element). The mapping between the property and / or the value may be signaled by RRC and / or MAC.

[0121] Receiving and / or monitoring for a DCI with or using an RNTI may mean that the CRC of the DCI is masked and / or scrambled with the RNTI.

[0122] The WTRU may use scheduling request (SR) for requesting UL-SCH resources for new transmission. The WTRU may use SR for sending one or more requests, indications, and / or reports, for example to a gNB. The WTRU may be configured with zero, one, or more SR configurations. An SR configuration may consist of a set of PUCCH resources for SR across different BWPs and / or cells. The WTRU may be configured with at most one PUCCH resource for SR per BWP, e.g, for a logical channel or for secondary cell (SCell) beam failure recovery and / or for consistent LBT failure recovery. The WTRU may be configured with for example up to two PUCCH resources for SR per BWP, e.g, for beam failure recovery of BFD-RS set(s) of serving cell.

[0123] Each SR configuration may correspond to one or more logical channels, SCell beam failure recovery, consistent LBT failure recovery, beam failure recovery of a BFD-RS set, and so forth. In an example, each logical channel, SCell beam failure recovery, beam failure recovery of a BFD-RS set andconsistent LBT failure recovery, may be mapped to zero or one SR configuration, which may be configured via RRC.

[0124] Herein, a signal may be interchangeably used with one or more of following: SRS, CSI-Rs, DM-RS, SSB, and / or phase tracking reference signal (PT-RS). A channel may be interchangeably used with one or more of following: PDCCH, PDSCH, PUCCH, PUSCH, PUCCH, PUSCH, and / or PRACH. A signal, channel, and / or a message (e.g., as in DL or UL signal, channel, and / or message) may be used interchangeably, but still consistent with this invention. RS may be interchangeably used with one or more of RS resource, RS resource set, RS port, and / or RS port group. RS may be interchangeably used with one or more of SSB, CSI-RS, SRS, and / or DM-RS, TRS, PRS, and PTRS. The terms time instance, slot, symbol, and / or subframe may be used interchangeably. The terms SSB, SS / PBCH block, PSS, SSS, PBCH, and / or master information block (MIB) may be used interchangeably. The terms SSB, SSB beam, and / or SSB index may be used interchangeably. The proposed solutions estimation and / or prediction may be used for transmissions and / or receptions belonging to a single and / or multiple cells as well as single and / or multiple TRPs. CSI reporting may be interchangeably used with CSI measurement, beam reporting, and / or beam measurement. A RS resource set may be interchangeably used with a beam group. The terms prediction, estimation, calculation, evaluation, and / or determination may be used interchangeably. RSRP may be used interchangeably with SS-RSRP, CSI-RSRP, SRS-RSRP, RSRP measured based on DMRS in PBCH, RSRP measured based on DMRS in PDCCH, RSRP measured based on DMRS in PDSCH, RSRP measured based on DMRS in PUCCH, and / or RSRP measured based on DMRS in PUSCH, etc. The terms traffic, user-plane (UP) traffic, control-plane (CP) traffic, etc., may be used interchangeably.

[0125] Methods based on beam failure recovery (BFR) and / or beam switching may increase the signaling overhead, escalate latency (due to switching gaps), and / or raise power consumption at both the network (NW) and / or WTRUs. BFR and / or beam switching may be avoided, as the WTRU does not expect urgent traffic. Discussed herein are efficient methods for beam management using AI / ML in mobility scenarios.

[0126] A solution may include postponing beam failure detection based on traffic status. For example, a WTRU that has predicted a blockage may determine and / or predict potential user plane function (UPF) or control plane (CP) traffic (using AI / ML). If there is no urgency for uplink (UL) and / or downlink (DL), then WTRU1 may postpone going into BFD and / or BFR mode.

[0127] A WTRU may have capability of predicting a blockage (e.g., a drop below a threshold in beam quality and / or RSRP for a possibly predicted finite duration), traffic status, and / or the best beam after a blockage duration is over.

[0128] The WTRU may predict a blockage on a first beam (or RS) and / or corresponding blockage time duration. The prediction may be based on at least one of: AI / ML model, and / or measurements on one or more configured first BFD-RS sets (e.g., via trained model that is based on fingerprinting at gNB).

[0129] The WTRU may predict a second beam (or RS) that may be the best beam (or RS) after the blockage is finished (e.g., a second beam per BFD-RS set). The second predicted beam (or RS) may or may not be included in the configured first BFD-RS sets. A blockage may be determined to be finished based on at least one of: predicted blockage time duration elapsing, predicted, and / or actual beam quality and / or RSRP may be higher than threshold.

[0130] The WTRU may determine and / or predict potential traffic status (e.g., for the duration of the predicted blockage). Status may include amount of traffic and / or traffic type and / or priority. The WTRU may postpone the beam failure detection and / or associated BFR in case the determined and / or predicted traffic is low priority (not urgent), the determined and / or predicted amount is less than a threshold, and / or blockage duration is shorter than a time threshold.

[0131] The WTRU may perform a handshake, the WTRU may indicate at least one of: the predicted blockage and / or blockage timing (e.g., start, end, and / or duration), the determined and / or predicted traffic status to gNB (e.g., prior to the start time of the blockage), whether the WTRU has determined to postpone the beam failure detection and associated BFR, and / or predicted second beam (or RS). As part of CSI report, or via separate SR. The WTRU may indicate that WTRU has predicted the blockage. Due to low traffic, the WTRU may postpone the BFR. The WTRU may indicate the BFD-RS set for which blockage is predicted. Indication may include the second predicted beam, BFR time duration to postpone (TPP_BFR), WTRU’s location, RSRP measurement of BFD-RS set for which blockage is predicted, etc.

[0132] The WTRU may receive confirmation and / or rejection and / or an enabling and / or disabling indication from gNB. If confirmed, the WTRU may receive indication on the time duration for which to postpone BFD and / or associated BFR (e.g., a postponement period), corresponding parameters, etc. The WTRU may postpone the BFD and / or associated BFR. If rejected, the WTRU may perform BFR; the WTRU may report the beam failure; and / or the US may send RACH, etc.

[0133] After the BFD and / or associated BFR postponement procedure is finished and / or one or more of the blockage time duration or the time duration to postpone BFD and / or associated BFR has elapsed, theWTRU may determine if the BFD condition still applies (e.g., based on measurements of the configured BFD-RS sets). The WTRU may attempt to detect CORESET and / or receive PDCCH to measure the beam quality (e.g., based on PDCCH DMRS).

[0134] If the condition still applies, the WTRU may perform BFR e.g., the WTRU reports the beam failure; and / or sends RACH, etc.) If the condition no longer applies, the WTRU may send a report to gNB. The WTRU may send an UL transmission (e.g., via SR, UCI, and / or MAC-CE, etc.) indicating that beam failure was avoided. The WTRU may report the measurements made before and / or during blockage, if any, e.g., for gNB training purposes.

[0135] Currently in NR Release 18 (R18), if a WTRU detects a (pre)configured number of beam failure instances (BFIs), the WTRU may trigger BFD and / or perform BFR. As seen in FIG. 2, WTRU1 210 is served by beam #2 240 and / or detects BFD and / or initiates BFR by switching to beam #1 230. This switch may result in exceeded traffic in beam #1 230. Based on current specifications, WTRU1 210 may not switch back to beam #2 240 even after the blockage end, resulting in more traffic in beam #1 230.

[0136] Based on previous technology, WTRU1 210, which beam #2 240 serves, may predict beam #1 230 or beam #3 250 to be the best candidate beam (based on WTRU1 210’s movement and / or direction). WTRU1 210 may initiate BFR and / or request to switch to beam #1 230 and / or beam #3 250 in advance or before BFD. This switching may result in heavier traffic at gNB side in beam #1 230 or beam #3 250, since WTRU1 210 may not switch back to beam #2 240 until another event (BFD and / or PDCCH order) is detected.

[0137] In general, two types of blockages in the context of AI / ML systems may be considered: predictable blockage and non-predictable blockage. Predictable blockage is when the WTRU uses the AI / ML model (e.g., mapping and / or fingerprinting) in the corresponding beam (e.g., beam #2 240) that WTRU1 210 received (e.g., offline and / or from the gNB, e.g., based on model trained at the gNB). So, if the blockage 260 is stationary, WTRU1 210 may already be aware of it. WTRU1 210 may then predict the time needed to pass through the blockage 260. Non-predictable blockage is when the blockage occurs suddenly and / or may be due to dynamic changes in the environment. Accordingly, the WTRU may not be able to predict such a blockage.

[0138] The WTRU may determine and / or predict traffic and / or congestion level. A WTRU may perform one or more of the following: a WTRU may receive indication regarding its traffic level (e.g., data volume, throughput, latency, and / or jitter, etc.). UL and DL may be indicated separately, or one common indication may exist for both. The indication may be different data radio bearer (DRB) granularity. The DRBgranularity may be total UP, CP, level, at DRB level, at a DRB group level, and / or where the group may be based on some QoS profile of the DRBs (e.g., whether they are guaranteed bit rate bearers or not, etc.). The indication could be associated with one or more time horizons and / or durations (e.g., X Mbytes expected within 1 sec, Y Mbytes expected within 2 sec, etc.). The indication may refer to already available data that may be pending for transmission (e.g., DL data that waiting for transmission at a network node). The indication may refer to data expected to become available soon (e.g., within a certain time duration). There could a separate indication for the pending and / or predicted data, or one common indication for both.

[0139] A WTRU may receive an indication regarding the congestion state from the network. There may be a separate indication for UL and / or DL, or one common indication for both. The indication may be at cell group level (e.g., for a master cell group (MCG) and / or a secondary cell group (SCG) in the case of dual connectivity, for the primary cell (PCell) and / or all the secondary cells (SCells), for a subset of the SCells, etc.), cell level, beam level, and / or a group of beams. The indication may be a simple flag indication (e.g., congested or not congested). The indication may have more granularity (e.g., not congested, slightly congested, and / or highly congested, etc.). The indication may contain time duration information (e.g., for how long the indication congestion level is expected to last).

[0140] Alternatively, the WTRU may determine and / or predicts potential traffic (e.g., volume and / or throughput, etc.). Based on buffer status monitoring at the WTRU, if the WTRU experiences buffer overflow, then the WTRU may determine high traffic. The WTRU may monitor the time spent by packets in any of the L2 buffers (e.g., packet data convergence protocol (PDCP) buffer, RLC buffer, MAC buffer, etc.). Time may be absolute value, or with respect to the packet delay budget (PDB) associated with the protocol data unit (PDU) (e.g., PDB configured for the bearer the PDU belongs to, and / or the PDCP discard time configured for the bearer the PDU belongs to, etc.). Based on traffic and / or congestion state prediction, input parameters to the AI / ML model would be for example time spent in different L2 buffers with the added aspect of the applicable prediction time window.

[0141] The WTRU may determine the time duration. During the time duration, there may not be an urgent UL and / or DL traffic based on the received indications and / or predictions on traffic status.

[0142] The WTRU may receive the indication regarding the traffic volume and / or congestion levels in several ways, included via a dedicated message (e.g., RRC signaling, PDCP control DU, RLC control PDU, MAC CE, and / or DCI); and / or via a broadcasted message (e.g., via RRC message, SIB signaling, and / or group DCI).

[0143] There may be separate traffic volume and / or congestion level indications, and / or there could be one common indication for both. The indications may contain explicit information (e.g., details like buffer levels, time durations, and / or congestion level, etc.). The indications may be just indexes, where the network has pre-configured the WTRU with the association of the indexes to the detailed traffic volume and / or congestion related information. A combination of the two may be envisioned where the indication contains some explicit information and / or some pre-configured indexes. For example, the buffer level may be an index to a buffer level table that the WTRU is pre-configured with, like legacy buffer status reporting. Congestion level and / or duration may be explicitly included in the indication.

[0144] Some bearers may be configured to be “undeferrable” even if there is no traffic pending, if there is a certain level of traffic pending, and / or if there has been not more than a certain duration since the arrival of the last DL data for this bearer or since the transmission of the last UL data for this bearer.

[0145] The WTRU may receive an indication from the network on the congestion state at the network. The network may determine the congestion state based on the number of WTRUs currently being served by the respective gNBs, the number of WTRUs it expects to serve in the upcoming future (e.g., WTRUs in INACTIVE state), and the scheduling needs of the traffic of the respective WTRUs. The granularity and / or number of indications that the WTRU receives from the network may include any one or more of the following: the WTRU may receive an indication from the network only when congestion status is bad and / or critical; the WTRU may receive a periodic indication from the network on the congestion status; the WTRU may receive one congestion status indication from the network for all types of traffic; he WTRU may receive a congestion status indication for UL traffic and / or another one for DL traffic.

[0146] The WTRU may receive congestion status indication for the type of traffic and / or service currently being used at the WTRU (e.g., ultra reliable and low latency (URLLC) traffic, extended reality (XR) traffic, enhanced massive mobile broadband (eMBB) traffic, etc.). For the UL traffic, for example, the WTRU may send an indication to the gNB on the type of traffic during the UL PDU session establishment. Such an indication, in addition to allowing the scheduler at the network to proportion and / or provision resources to the WTRU accordingly, may also determine the WTRUs primarily impacted by the congestion. For example, URLLC traffic may be prioritized over eMBB traffic and / or the congestion status may be different for each type of traffic. Congestion status for URLLC traffic may be set as ‘intermediate’ while that for eMBB traffic (e.g., which is less important) may be set as ‘critical’ to prioritize URLLC traffic in the UL. In other words, the NW may determine the future traffic, traffic priority level, and / or quality of service (QoS) priority levels, etc. based on one or more indications received from WTRU based on the UL data.

[0147] The gNB may perform RRC reconfiguration on detection of congestion and / or congestion considered as ‘critical’. In such case, the gNB may send to the WTRU an RRC reconfiguration message. The reconfiguration message may include information on the congestion status such as impacted DRBs, expected length of congestion, and / or any resulting reconfiguration (e.g., activate new set of DRBs, activate another configured grant (CG) configuration, etc.) etc. In response, the WTRU may send a RRC reconfiguration complete message to acknowledge the reconfiguration process (including the information on congestion).

[0148] The congestion indication from the network may include additional information, e.g., on the beams impacted by congestion. This may include impacted SSBs (e.g., in terms of SSB IDs), impacted CSI-RS beams (e.g., in terms of CSI-RS beam IDs), any correlation information between UL and DL beams (e.g., DL transmission (Tx) beam ID X corresponding to UL reception (Rx) beam ID Y), information on the new beam(s) to use as a result of the congestion (e.g., use SSB 2), and / or any correlation information between different beams or types thereof (e.g., if SSB 1 is impacted by congestion, use SSB 2). This may additionally include the expected time duration the beam(s) may be impacted and / or when to use the alternative beam(s).

[0149] The signaling of the congestion may occur in different ways. For example, a WTRU may receive one indication of the congestion status, e.g., in a MAC CE and / or scheduling DCI. The network may detect congestion on a per-data radio bearer (DRB) basis. In such case, the gNB may send the congestion indication in: PDCP and / or radio link control (RLC) control PDU from PDCP and / or RLC entity in the gNB for the concerned bearer to corresponding PDCP / RLC entity in the WTRU.

[0150] The gNB may send the congestion indication in the MAC CE with a bitmap introduced for congestion indication on a per-DRB basis to efficiently control multiple DRBs separately and simultaneously, e.g., an 8-bit bitmap corresponding to DRBs configured in the WTRU. When congestion indication may be signaled per type of traffic, the 8-bit bitmap may correspond to DRBs configured for the type of traffic for which congestion is being indicated, e.g., DRBs configured to serve eMBB traffic. When the WTRU may be configured with a large number of DRBs, there may be more than one format MAC-CE configured to indicate congestion on a per-DRB basis, e.g., a 16-bit bitmap in addition to an 8-bit bitmap for indication for a larger number of DRBs.

[0151] Any one or more of the solutions may involve the WTRU receiving a configuration from the network on congestion status indication, e.g., during RRC (re)configuration. Such configuration may include: periodicity for periodic congestion indication, granularity of congestion indication, one configuration for alltraffic and / or one configuration for UL traffic and / or another configuration for DL traffic, and / or one configuration for all traffic types and / or one configuration per traffic type (e.g., URLLC, eMBB, XR and / or traffic etc.).

[0152] The WTRU may send a request to the network on the current and / or upcoming congestion state. The request may be on any granularity as mentioned before, for example, one general indication and / or one indication per type of traffic (e.g., UL vs. DL, and / or eMBB vs. URLLC vs. XR, etc.). The WTRU may receive a congestion indication from the network in response to the request sent from the WTRU. The WTRU may send such requests periodically to the network. The WTRU may be configured with a set of SRs, where the WTRU may determine to transmit a first SR to implicitly indicate one or more indications (e.g., to a gNB).

[0153] The WTRU may send an aforementioned indication in any one or more of the following: when the WTRU has sent one or more scheduling request(s) and has not received any response and / or UL grant from the network in response. In such condition, the WTRU may determine that there is congestion and send a request to the network to confirm; when the WTRU has sent multiple scheduling requests and has reached the maximum counter sr_TransMax such that WTRU cannot send any more SR and / or WTRU has not received an UL grant from the network in response; when WTRU has sent an SR to the network and the SR prohibit timer is still running such that WTRU cannot send another SR to the network and / or WTRU has not received an UL grant from the network in response to the SR; and / or when WTRU has sent buffer status report (BSR) to the network and has not received any UL grant from the network in response to the BSR.

[0154] Reception of an indication from the network, e.g., within a preconfigured time window may indicate no congestion. In another solution, reception of no indication from the network may indicate that congestion status is so bad that the WTRU cannot receive any indication.

[0155] The WTRU’s request for network congestion information may be triggered based on current status of the beam failure monitoring process. For example, the WTRU may send the request to the network if the current counter value of the BFI reaches a certain threshold (e.g., a threshold lower than the BIF MAX value that is used to detect BF and / or trigger the BFR). The indication from the WTRU to request congestion level from the network may be a UCI, a MAC CE, an RLC control PDU, a PDCP control PDU, and / or an RRC message. The indication from the WTRU to request congestion level may include detailed information such as the concerned traffic (e.g., radio bearers, and / or QoS profile, etc.) and / or the network (e.g., identities of cells, and / or beams, etc.).

[0156] The scheduler at the network has information on multiple WTRUs that it serves and / or m to proportion resources to those multiple WTRUs. Therefore, the scheduler may know about current congestion status as well as upcoming congestion status for a time window in the future. The length of the congestion time window and / or severity of the congestion may depend on the scheduling requirements of the WTRUs currently being served. Such scheduling requirements may include any one or more of: UL and / or DL traffic patterns of the WTRUs being served, CG configuration details of WTRUs being served (e.g., size and / or periodicity of configured grants, and / or offset to CG configuration, etc.), semi-persistent scheduling (SPS) configuration details of WTRUs being served (e.g., size and / or periodicity of DL grants), scheduling requests received so far by gNB, number of BSR requests (e.g., regular BSR, pre-emptive BSR, and / or periodic BSR) received by gNB, details included in the BSR requests (e.g., size of grant requested by WTRU in BSR, periodicity of periodic BSR, etc.), DSR (delay status report) indications received by the network containing information on the remaining delay for data in respective WTRU buffers (e.g., remaining time until PDB expires, etc.).

[0157] The WTRU may determine and / or predict the traffic conditions based on one or more of the following: buffer status and / or buffer level monitoring at the WTRU. If the WTRU experiences buffer overflow, the WTRU may determine that there is heavy traffic and / or the traffic is higher than a determined and / or (pre)configured threshold. If buffer levels at WTRU are filled at >X% (e.g., X = 80) continuously (e.g., for a preconfigured time window), the WTRU may determine that there is heavy traffic. The WTRU may monitors the time that the traffic spends in any of the L2 buffers (e.g., PDCP buffer, and / or MAC buffer, etc.). The time spent in buffer calculation may be based on existing PDCP discardTimer if determined at PDCP sublayer and / or based on a new timer at MAC if determined at MAC sublayer. The WTRU may determine remaining time of data in any of its L2 buffers. For example, remaining time may be with respect to the PDB associated with the PDU or the PDU set delay budget (PSDB) associated with the PDU set. The remaining time calculation may be based on existing PDCP discardTimer if determined at PDCP sublayer or based on a new timer at MAC if determined at MAC sublayer.

[0158] The WTRU may determine and / or predict the traffic conditions based on unanswered and / or unfulfilled SR and / or BSR requests. If WTRU receives no UL grant in response to one or more SR requests and / or BSR requests, the WTRU may determine that there is congestion.

[0159] The WTRU may determine and / or predict the traffic conditions based on partially fulfilled BSR requests. If the WTRU sends a request for an UL grant of size X but WTRU gets a smaller grant of size Y than what it reported in the BSR table, the WTRU may determine that the NW cannot grant the requestedresources due to congestion. Alternatively, if WTRU receives an UL grant that is not sufficient to send the indicated traffic volume level in the BSR, the WTRU may determine that the NW cannot grant the requested resources due to congestion.

[0160] The WTRU may determine and / or predict the traffic conditions based on an indication from application. In the UL, the WTRU may receive an indication from the application in the application layer on the upcoming traffic. For example, a WTRU sending XR traffic in the UL may receive an indication on the XR traffic from the XR application in the WTRU. Such indication may include information on UL jitter (since jitter is generated at the application) and / or UL traffic periodicity and / or an upcoming surge in traffic. Based on this indication and / or other information (e.g. , on the CG configuration at the WTRU and / or ongoing and / or unfulfilled SR / BSR requests), the WTRU may determine that it experiences congestion in a current and / or upcoming time window.

[0161] The WTRU may determine and / or predict the traffic conditions based on AI / ML operation at the WTRU. The WTRU may have AI / ML model(s) to determine and / or predict congestion and / or upcoming congestion and / or any one or more of the aforementioned parameters associated with the congestion (e.g., duration of congestion, impacted DRBs, and / or impacted SSBs, etc.). Input parameters to the AI / ML model(s) may be for example time spent in different L2 buffers with the added aspect of the applicable prediction time window and any of the aforementioned parameters associated with congestion. Other input parameters to the AI / ML model(s) (e.g., in determining network congestion level) may be for example time of the day, WTRU location (e.g., current cell or geographical location, etc.).

[0162] The WTRU may report the determined and / or predicted traffic level and / or delay status to the NW. The WTRU may report periodically, upon determination of current and / or predicted traffic level, and report the delay status at the WTRU, on receiving a request from the NW requesting for determined, predicted traffic level, and / or delay status report at the WTRU.

[0163] The WTRU may determine the time duration during which there will not be an urgent UL and / or DL traffic based on the received indications, determination, and / or prediction of traffic status at the WTRU.

[0164] A WTRU may be configured with and / or determine one or more traffic levels based on the received indications, determined, and / or predicted data traffic, data congestion, etc., as described herein. The WTRU may determine the traffic levels based on a first traffic level (e.g., high traffic), a second traffic level (e.g., moderate traffic), a third traffic level (e.g., low traffic), etc.

[0165] After receiving one or more congestion detection and / or an indication reception from the network, the WTRU may perform different operations in L1 / L2 differently. For example, based on the WTRU’sdetermination of potential traffic and / or no urgency for UL / DL data transmissions and / or receptions (e.g., the traffic currently buffered at the WTRU or the active traffic in the DL belongs to bearers that have very relaxed latency or / and throughput requirements), WTRU may modify the BF detection and / or recovery process. The WTRU may modify the BF detection by extending the max BFI counter value, reset and / or suspend the BFI counter, and / or reset and / or suspend the BFD timer, etc.

[0166] Based on the determination of heavy congestion in the network (e.g., determined by the WTRU itself or based on received indication from the network), the WTRU may modify the BF detection and / or recovery process. The WTRU may modify the BF detection and / or recovery process by extending the max BFI counter value, reset and / or suspend the BFI counter, and / or reset and / or suspend the BFD timer, etc.

[0167] The WTRU may refine the best one or more beam(s) prediction based on detection and / or prediction of traffic status. The WTRU may expand the number of and / or refine the identity of the candidate beam(s) for beam failure recovery following detection and / or prediction of traffic status. The WTRU may not monitor the impacted one or more beams by the congestion, (e.g., impacted SSB(s)).

[0168] Other L2 operations, such as discarding and multiplexing, in the presence of congestion, at the PDCP sublayer, the WTRU may discard PDUs of low priority and / or importance that the WTRU would still try to transmit under normal conditions (of no congestion). Or for multiplexing at the MAC sublayer, in the presence of congestion, the WTRU may not multiplex PDUs of low priority and / or importance into a MAC PDU and / or prioritize PDUs of higher priority / importance.

[0169] A WTRU may be configured with one or more QoS profiles, including one or more QoS flows, where each QoS flow is identified via a QoS Flow Identifier (QFI). The WTRU may receive one or more QFIs of one or more QoS flows of a PDU session to be mapped to one or more data radio bearers (DRB). The QoS flows may be mapped via higher layer parameters (e.g., mappedQoS-FlowsToAdd) as part of Service Data Adaptation Protocol (SDAP) configurations. The WTRU may receive configured QoS profiles, QoS flows, and / or QFIs, etc. as part of RRC configuration and / or RRC reconfiguration messages.

[0170] Data packets originate in the application layer from an application. The non-access stratum (NAS) layer may assign QoS requirements and / or mapping rules. The NAS may map data and / or IP flows carrying data packets to a QoS flow and / or configure a QFI for each QoS flow. All data packets within the same QoS flow thus have the same QFI. The access stratum (AS layer) maps a QoS flow to radio layer resources whereby the SDAP entity within the WTRU maps a QoS flow to a DRB. All data packets mapped to the same DRB therefore have the same transmission treatment in AS (e.g., from a radio interface perspective). SDAP QoS flow to DRB mapping rules may be configured semi-statically in RRC. TheWTRU-SDAP may therefore map an SDU to a DRB according to the configured rules, and / or to the default DRB if no rules are configured. An RRC may configure each DRB with one or more logical channels (LCHs). Finally, the link control protocol (LCP) function in WTRU-MAC may allocate UL radio resources among the LCHs with buffered data in the WTRU. The allocation may be based on configured QoS related LCP parameters (e.g., LCH’s priority, the LCH’s prioritized bit rate (PBR), bucket size duration (BSD), and / or the LCH’s LCP mapping restrictions configured per LCH).

[0171] A WTRU may determine one or more priority levels for the configured QoS flows based on one or more configured QoS requirements. For example, the WTRU may determine the priority levels based on a first priority level (e.g., high priority), a second priority level (e.g., moderate priority), a third priority level (e.g., low priority), and so forth.

[0172] A WTRU may be configured with one or more QoS requirements for the received, determined, and / or configured QoS flows. One or more of the following QoS requirements may apply: the Error Rate. A WTRU may be configured with one or more types of QoS based on one or more levels of expected error rates, (e.g., PDU set error rate (PSER)). For example, a first type of QoS flow may include a guaranteed bit rate (GBR), where the WTRU receives configurations on one or more of the guaranteed bit rates (e.g., unit may be Kbit / s), maximum bit rates (e.g., in Kbit / s), etc. A second type of QoS flow may be non-GBR. The WTRU may determine the first type of QoS flow to have the first priority level if the configured GBR is higher than a corresponding threshold. The WTRU may determine the first type of QoS flow to have the second priority level if the configured GBR is lower than the corresponding threshold. The WTRU may determine the second type of QoS flow to have the third priority level, etc.

[0173] Another QoS requirement that may apply is a delay bound. A WTRU may receive and / or transmit one of more service data flows (SDF) as part of one or more PDUs. The SDFs may apply for different applications, where each SDF may have distinct service QoS requirements. The WTRU may be configured with one or more levels of PDU set delay bound (PSDB). The WTRU may determine one or more priority levels for the SDFs as part of analyzing the packets for the corresponding UPF (e.g., by using packet detection rules (PDR)). The WTRU may determine priority levels based on QoS enforcement rules (QER), the configured PSDB, and / or corresponding QFI associated with the PDRs. The WTRU may determine a QFI to have the first priority level if the configured PSDB is configured as low latency and / or is lower than a first delay bound threshold. The WTRU may determine a QFI to have the second priority level if the configured PSDB is higher than the first delay bound threshold and / or lower than a second delay boundthreshold. The WTRU may determine a QFI to have the third priority level if the configured PSDB is higher than the second delay bound threshold, etc.

[0174] The WTRU determines or receives configurations on the mode of operation and time duration for BFR postponing (TPP_BFR) on its active first e.g., original) beam, where one or more of the following modes may apply:

[0175] The first mode: hold the Rx / Tx. For example perform a WTRU-oriented semi-persistent / aperiodic discontinuous reception (DRX) and / or discontinuous transmission (DTX). The WTRU may be capable of predicting the best (second) beam in time domain. The WTRU may not monitor or receive any SSBs and / or RSs. The WTRU does not monitor SPS PDSCH occasions and / or PDCCH for dynamic grants / assignments for new transmissions. The WTRU may not transmit CG PUSCH occasions and / or SR occasions. The WTRU may determine short DRX time durations to avoid going into radio link failure (RLF) or out-of-sync. During DRX active mode, the WTRU may monitor paging to stay in-sync. After the time duration has elapsed, the WTRU may connect to the first original beam. The WTRU and / or the network may be synchronized with respect to when the WTRU is connected and / or reachable.

[0176] The procedure may be successful if WTRU monitors, receives, and / or measures PDCCH DMRS RSRP on the original first beam and / or the measured RSRP is higher than thresholds. The procedure may be unsuccessful if the WTRU cannot receive PDCCH or if the measured RSRP is lower than thresholds, based on the first original beam, WTRU uses the third or fourth modes of operation based on one or more (pre)configured information in addition to accuracy of beam prediction, predicted second beam, etc. If “prediction accuracy is acceptable” and “second beam is different from the first beam” then the WTRU may use the third mode of operation. If “prediction accuracy is acceptable” and the “second beam is the same as the first beam” then the WTRU uses the fourth mode of operation. If “prediction accuracy is fair or not acceptable” then the WTRU may use the fourth mode of operation.

[0177] The second mode: modify BFI counter, BFI max count, and / or BFD timer and / or set of candidate beams. The WTRU may monitor corresponding SSBs and / or RSs and increments BFI counter until reaching a (pre)configured first (legacy) MAX (e.g., maximum) value. Upon reaching the first MAX counter, the WTRU may continue monitoring and / or attempting to detect corresponding CORESET, PDCCH, SSBs, RSs, etc. until the BFI counter reaches a second MAX value (e.g., for an extended period). The WTRU may monitor a first set of BFR candidate beams and / or a second set of BFR candidate beams during the extended period to select one or more best candidate beams. After the extended time period has elapsed, the WTRU may try to connect to the original first beam.

[0178] The procedure may be successful if the WTRU monitors, receives, and / or measures PDCCH DMRS RSRP on the original first beam and / or the measured RSRP is higher than thresholds. The WTRU may send a report to gNB. The procedure is unsuccessful if either of below conditions apply: if the WTRU cannot receive PDCCH and / or if the measured RSRP is lower than a threshold based on the first original beam. The procedure may be unsuccessful if the second MAX value is reached within the postponing time duration (TPP_BFR). In case of unsuccessful procedure, the WTRU uses the 4th mode of operation (legacy BFR) to connect to the best selected candidate beam.

[0179] The third mode: skip the BFR and / or perform beam switching to the second (predicted) beam. WTRU may be capable of predicting the best (second) beam in time domain. The WTRU may not measure the candidate beams and / or after the time has lapsed, the WTRU directly connects (e.g., performs RACH) based on the determined and / or predicted second beam. If the connection to the second predicted beam is not possible and / or if the beam quality of the second predicted beam is not acceptable, the WTRU may use the fourth mode of operation based on the original first beam.

[0180] The fourth mode: fall back to legacy BFR based on the original first beam. In the fourth modes of operation, after the RLF timer has lapsed, if the beam quality of none of the candidate beams are not acceptable, the WTRU may initiate RLF recovery. The WTRU may send an indication (e.g., via a flag in BFR MAC-CE) to indicate the reason the fallback to legacy BFR is being used.

[0181] Herein, one or more thresholds and / or MAX values for timers and / or counters can , ay indicated and / or configured (e.g., by a gNB) via one or more of RRC, MAC-CE, and / or DCI. The WTRU may be configured with one value for the actual operation (e.g., via one of RRC, MAC-CE, and / or DCI). The gNB may configure the WTRU with two or more candidate values (e.g., via RRC and / or MAC-CE) and / or indicate one value for the actual operation (e.g., via MAC-CE and / or DCI).

[0182] The WTRU may support BFR postponing. The WTRU may determine a mode of operation for BFR postponing based on a first beam (e.g., activated and / or indicated beam by a gNB, e.g., for transmitting and / or receiving one or more channels and / or signals). The WTRU may receive an indication of a mode of operation for BFR postponing based on the first beam (e.g., via one or more of RRC, MAC-CE, and / or DCI). In another solution, the WTRU may determine and / or receive configuration information on the time duration to perform and / or postpone the BFR postponing (e.g., TPP_BFR). The determination and / or indication of the mode of operation and / or the time duration may be based on one or more of the following modes:

[0183] The first mode: perform a WTRU-oriented semi-persistent and / or aperiodic DRX / DTX (e.g., a WTRU-oriented hold of Rx / Tx). The WTRU may hold, stop, and / or disable Rx / Tx. The WTRU may perform a WTRU-oriented semi-persistent and / or aperiodic DRX / DTX in the first mode of operation. In this mode, the WTRU may stop monitoring, receiving, measuring, and / or transmitting one or more signals and / or channels. The WTRU may not monitor and / or receive one or more of SSBs, RSs, SPS PDSCH occasions, PDCCH for dynamic grants and / or assignments for new transmissions, etc., for example during the configured and / or determined DRX / DTX duration. The WTRU may not transmit uplink signals and / or channels, for example PUSCH in CG PUSCH occasions, SR occasions, etc., for example during DRX / DTX duration.

[0184] The WTRU may determine holding Rx / Tx related parameters. The related parameters may be associated with the WTRU oriented semi-persistent and / or aperiodic DRX / DTX. If the WTRU determines a set of DRX / DTX parameters for semi-persistent DRX / DTX, aperiodic DRX / DTX, and / or postponing BFR, the WTRU may determine to use a first or a second set of DRX / DTX related parameters. The WTRU may use short DRX / DTX time duration as the first set of DRX / DTX parameters, for example to avoid going into RLF and / or out-of-sync modes. That is, the WTRU may determine that the determined and / or configured BFR postponing time duration (e.g., TPP_BFR) may be longer than a corresponding threshold, after which the WTRU that tries to connect via the first original beam may experience RLF and / or go out-of-sync. As such, the WTRU may determine to use short DRX / DTX time durations to avoid going out-of-sync and / or in RLF. The WTRU may predict and / or determine that the possibility of the WTRU going into out-of-sync and / or RLF is low. The WTRU may predict that the WTRU may be in the center of the cell with high received power (e.g., RSRP). Thus, the WTRU may determine to use the second set of DRX / DTX parameters (e.g., with long DRX / DTX time duration).

[0185] The WTRU may apply the determined set of DRX / DTX related parameters (e.g., based on the DRT / DTX type) for DRX / DTX operation. The WTRU may monitor paging signaling via monitoring paging PDCCH in associated CORESETs and / or search spaces (e.g., to stay in-sync).

[0186] In the first mode, the WTRU may apply, use, send, and / or receive one or more channels and / or signals using the first beam after expiration of BFR postponing time duration (e.g., TPP_BFR). The WTRU may determine if the performance of reception and / or transmission may be acceptable based on the first beam, where the WTRU may determine the mode of operation accordingly.

[0187] In the first mode the WTRU, successful BFR postponing may occur. The WTRU may attempt to receive and decode paging PDCCH in associated CORESETs and / or search spaces and / or determine thereceived signal power (e.g., RSRP). The WTRU may atempt to receive, detect, and / or measure one or more configured PDCCH DMRS RSRP based on the original first beam. The WTRU may determine that the performance of the first beam is acceptable if the measured RSRP is higher than corresponding thresholds. As such, the WTRU may determine that postponing the BFR was successful and so the WTRU may continue to receive and / or transmit signals and channels based on the first beam.

[0188] Unsuccessful BFR postponing. For example, if the WTRU does not receive, detect, and / or decode paging PDCCH, and / or if the measured RSRP of the received PDCCH DMRS is lower than thresholds, the WTRU may determine that the BFR postponing was not successful and to use another mode of operation.

[0189] The WTRU may be capable of predicting a second beam (e.g., best beam) in time domain. The WTRU may be capable of predicting the second best beam, e.g., X ms from the current time instance. The WTRU may be capable of predicting the second best beam after the configured time duration for BFR postponing (e.g., TPP_BFR).

[0190] Unsuccessful BFR postponing may occur. One or more of the following examples may apply: if the WTRU is capable of beam prediction and / or the prediction accuracy for predicting the second beam is higher than a prediction accuracy threshold, and that the predicted second beam is different from the original first beam, then the WTRU may determine to use the third mode of operation. If the WTRU may be capable of beam prediction and / or if the prediction accuracy for predicting the second beam is higher than a prediction accuracy threshold, and that the predicted second beam is the same as the original first beam, then the WTRU may determine to use a fourth mode of operation, as described herein. The WTRU may send an indication, for example as part of a report, for example via a flag in BFR MAC-CE, where the indication may indicate that the first mode of operation was selected. Since it was unsuccessful, the WTRU performed fall back to fourth mode of operation. For example, if the WTRU is not capable of beam prediction and / or if the prediction accuracy for predicting the second beam is lower or equal to a prediction accuracy threshold, then the WTRU may determine to use the fourth mode of operation.

[0191] The second mode: extending beam failure detection procedure. The WTRU may postpone BFR by extending the BFD procedure by applying different BFI counters, timers, set of monitoring beams for beam failure detection, and / or set of candidate beams for new beam selection, etc. The WTRU may use the second mode of operation if the WTRU determines and / or indicates its capability on extending BFI counter, timer, and / or set of candidate beams, etc.

[0192] The WTRU may be configured with two or more sets of BFR configurations. For example, a first set of BFR configurations may be used if the WTRU supports a normal and / or legacy BFR mode that doesnot include supporting the second mode of operation and / or extending BFI counter, timer, and / or set of candidate beams, etc. In other words, the normal and / or legacy BFR may include operation based on the originally configured first set of configurations. The second set of BFR configurations may be used if the WTRU supports extended BFR mode (e.g., second mode). The BFR configurations may include one or more of thresholds, counter MAX values, and / or timer MAX values, etc.

[0193] The WTRU may be configured with two or more sets of BFD-RSs. For example, a first set of BFD- RSs may be used if the WTRU support a normal and / or legacy BFR mode. The second set of BFD-RSs may be used if the WTRU support extended BFR mode (e.g., second mode).

[0194] The WTRU may be configured with two or more sets of new candidate beam (NCB) RSs. A first set of NCB RSs may be used if the WTRU supports a normal or legacy BFR mode. The second set of NCB RSs may be used if the WTRU support extended BFR mode (e.g., second mode).

[0195] The WTRU may monitor, detect, and / or measure BFD-RSs (e.g., one or more of qO, SSBs, and / or RSs). Based on the monitoring, detection, and / or measurement, the WTRU may detect beam failure. The WTRU may increase a BFI counter, if the measured quality of BFD-RSs is lower than a beam failure threshold (e.g., until reaching a (pre)configured first MAX value. If the WTRU determines a normal or legacy BFR mode and / or the beam failure counter reaches the first MAX value (e.g., configured in the first set of BFR configurations and / or before expiration of a first BFR timer), the WTRU may trigger BFR operation. If the WTRU determines the second mode (e.g., upon reaching the first MAX value within a beam failure counter), then the WTRU may continue monitoring, measuring, and / or attempting to detect beam failure (e.g., based on associated CORESETs, search spaces, PDCCHs, SSBs, and / or RSs, etc.) until the BFI counter reaches a second MAX value (e.g., configured in the second set of BFR configurations and / or before expiration of a second BFR timer, e.g., an extended period).

[0196] The WTRU may apply a different set of BFD-RSs (e.g., based on the first set of configurations). The WTRU may monitor the first set of BFD-RSs before expiration of a first timer and / or reaching the first MAX value of a first counter. After expiration of the first timer and / or reaching the first MAX value of the first counter, the WTRU may monitor the second set of BFD-RSs.

[0197] The WTRU may apply a different set of NCB RSs (e.g., based on the first set of configurations). The WTRU may measure the first set of NCB RSs before expiration of a first timer and / or reaching the first MAX value of a first counter. After expiration of the first timer and / or reaching the first MAX value of the first counter, the WTRU may measure the second set of NCB RSs. The WTRU may apply the first beam after expiration of the second BFR timer (e.g., based on the second mode).

[0198] The second mode considers successful BFR postponing. The WTRU may determine a mode of operation after extending BFR related configurations. For example, the WTRU may detect, receive, and / or decode PDCCH (e.g., WTRU and / or group-specific PDCCH in associated CORESETs and / or search spaces). The WTRU may measure corresponding PDCCH DMRS RSRP on the original first beam. The WTRU may determine that the performance of the first beam is acceptable if the measured RSRP is higher than corresponding thresholds. As such, the WTRU may determine that postponing the BFR was successful. Therefore, the WTRU may continue to receive and / or transmit signals and / or channels based on the first beam.

[0199] The second mode considers unsuccessful BFR Postponing. If the WTRU does not receive, detect, and / or decode PDCCH and / or if the measured RSRP (e.g., RSRP of measured PDCCH DMRS) is lower than corresponding thresholds, the WTRU may determine to use the fourth mode of operation, as described herein. The WTRU may send an indication, for example as part of a report, for example via a flag in BFR MAC-CE, where the indication may indicate that the second mode of operation was selected and / or since it was unsuccessful, the WTRU may perform fall back to fourth mode of operation.

[0200] The third mode: recover beam failure and / or perform beam switching based on beam prediction. A WTRU may use the third mode of operation if the WTRU may predict a second beam (e.g., best beam) in time domain (e.g., X ms from the current time instance).

[0201] The WTRU may detect one or more BFIs and / or trigger a BFR operation after reaching the MAX number of BFIs (e.g., within a timer), where the BFR operation may be based on a second predicted beam. The WTRU may determine that BFR postponing based on a configured and / or determined time duration (e.g., TPP_BFR) is unsuccessful, where the WTRU may trigger BFR operation based on a second predicted beam. The WTRU may determine one or more best beams based on predicted qualities (e.g., predicted RSRP) of NCB RSs that correspond to the second predicted beam. Based on the determined one or more best beams, the WTRU may indicate the one or more best beams (e.g., to the gNB). The WTRU may transmit one or more PRACHs (e.g., in associated PRACH resources with the one or more best beams). The WTRU may indicate the one or more best beams (e.g., indicating RS indexes and / or beam indexes, etc.). The indication may be one or more of RRC, MAC CE, UCI, special SR, as part of an enhanced HARQ-ACK, as part of CSI-RS, etc.

[0202] The third mode considers a successful procedure. The WTRU may attempt to receive, detect, and / or decode PDCCH (e.g., WTRU and / or group specific PDCCH in associated CORESETs and / or search spaces). The WTRU may measure corresponding PDCCH DMRS RSRP on the predicted secondbeam. In case the measured RSRP is higher than corresponding thresholds, the WTRU may continue to receive and transmit based on the second (predicted) beam.

[0203] The third mode considers an unsuccessful procedure. The WTRU may attempt to receive, detect, and / or decode PDCCH (e.g., WTRU and / or group specific PDCCH in associated CORESETs and / or search spaces). The WTRU may measure corresponding PDCCH DMRS RSRP on the predicted second beam. In case the measured RSRP is lower than corresponding thresholds, the WTRU may determine to use the fourth mode of operation, as described herein. The WTRU may send an indication, for example as part of a report, for example via a flag in BFR MAC-CE, where the indication may indicate that the third mode of operation was selected and since it was unsuccessful, the WTRU performed fall back to 4th mode of operation.

[0204] The fourth mode: fall back to legacy BFR based on the original first beam. The WTRU may detect one or more BFIs and / or trigger a BFR operation after reaching the MAX value (e.g., within a timer). After triggering the BFR operation, the WTRU may support the BFR operation based on a set of NCB RSs. The WTRU may determine one or more best beams based on measured qualities (e.g., measured RSRPs) of NCB RSs. Based on the determined one or more best beams, the WTRU may indicate the one or more best beams (e.g., to the gNB). The WTRU may transmit one or more PRACHs (e.g., in associated PRACH resources with the one or more best beams). The WTRU may indicate the one or more best beams (e.g., indicating RS indexes, beam indexes, etc.). The indication may be one or more of RRC, MAC CE, and / or UCI.

[0205] If the WTRU does not identify a new beam, or does not receive a PDCCH in associated CORESETs and / or search spaces (e.g., within a timer), or the measured RSRP based on PDCCH DMRS is lower than a corresponding threshold, the WTRU may determine that the BFR procedure is unsuccessful. As such, the WTRU may trigger one or more of contention-based RACH procedure and / or RLF recovery, etc.

[0206] A WTRU may be configured with one or more sets of reference signal (RS) resources, beams, and / or beam-pairs). Each RS resource, beam, and / or beam-pair may be associated with a transmission from a beam of specific beam parameters (e.g., beam direction and beamwidth). The WTRU may be configured with the associated beams and / or RS resources and / or the beam parameters.

[0207] A WTRU may be configured with a first set of RS resources, beams, and / or beam-pairs that may cover the entire RS resource-space, beam-space, and / or beam-pair-space. The WTRU may determine or select a set A and a set B such that the union of set A and set B may cover the entire RS-resource-space,beam-space, and / or beam-pair-space. Set A and set B may be mutually exclusive. Set B may include RS resources on which the WTRU may perform measurements to obtain direct measurement values for a first set of beams or beam-pairs (e.g., one-to-one mapping between an RS resource and a beam or beam-pair) and / or estimated measurement values for a second set of beams or beam-pairs (e.g., many-to-one mapping between RS resources and / or a beam or beam-pair and / or possibly using AI / ML estimation model).

[0208] A WTRU may be configured with requirements for Set A and / or Set B. A WTRU may be configured with one or more sets of RS resources associated to each beam. For example, a WTRU may be configured with a first beam associated with two sets of RSs: a first set including a single RS resource and a second set including multiple RS resources. A WTRU may determine measurements associated with the beam via direct measurements of the RS resources in the first set and / or via estimation obtained from measurements of the RS resources in the second set.

[0209] A WTRU may determine a measurement set of RS resources (e.g., a set B) such that for every beam for which the WTRU must obtain measurements (e.g., either directly or via estimation), the set B contains at least one of the two sets of RS resources associated to the beam. Herein, a Set B may be interchangeably used with a set of RS resource sets, beams, beam-pairs, beam RS resources, RS resources and / or a beam pattern. Herein, a Set A may be interchangeably used with a set of RS resource sets, beams, beam-pairs, beam RS resources, RS resources, and / or a beam pattern.

[0210] A WTRU may be (pre)configured with the maximum number of RSs and / or SSBs (e.g., within an SSB burst) in a cell. The maximum number of SSBs and / or RSs may be explicitly configured for the WTRU (e.g., via MIB, SIB, RRC, MAC-CE, and / or DCI, etc.). Alternatively, the maximum number of SSBs and / or RSs may be implicitly indicated to the WTRU, based on the used frequency range. If the WTRU is operating in a first frequency range (e.g., FR1), the WTRU may determine the maximum number of the SSBs and / or RSs to be a first value (e.g., maximum eight SSBs and / or RSs). If the WTRU is operating in a second frequency range (e.g., FR2), the WTRU may determine the maximum number of the SSBs and / or RSs (e.g., within a SSB burst) to be a second value (e.g., maximum 64 SSBs and / or RSs), etc.

[0211] A WTRU may detect one or more SSBs and / or RSs (e.g., within an SSB burst), for example during initial access, cell (re)selection, beam measurement, beam management, etc. Considering the maximum number of SSBs and / or RSs, only a subset of SSBs and / or RSs may be planned, configured, required, expected, and / or designed to be used (e.g., in a cell). The set of the planned SSBs and / or RSs may be a set of SSBs and / or RSs. The set may cover the entire SSB and / or RSs resource-space and / or beam-space. The number of planned SSBs and / or RSs may be lower than or equal to the maximum number of SSBs and / or RSs determined at the network based on the SSBs and / or RSs’ coverage space, correlation of the beams, etc. . The WTRU may be provided and / or configured with the number of planned SSBs, RSs, and / or the corresponding SSB and / or RS beam indexes.

[0212] The WTRU may receive, be provided, or be configured with the information on actual transmitted RSs and / or SSBs (e.g., within an SSB burst). The information may include the number of actual transmitted SSB and / or RSs beams, the SSB and / or RSs indexes corresponding to the actual transmitted SSB beams, and so forth. The WTRU may consider the set of actual transmitted SSBs and / or RSs as Set B, where Set B may be a subset of configured Set A. Alternatively, the WTRU may determine, be provided, or configured with a set of skipped SSBs and / or RSs. The set of skipped SSBs and / or RSs may not actually be transmitted in the corresponding SSB burst and / or RS transmission time window. The WTRU may use the set of transmission beams (Set B) to estimate and / or predict the beams that are not transmitted. The WTRU may consider the set of estimation SSBs and / or RSs as Set A.

[0213] The WTRU may be (pre)configured with one or more first configuration information on the transmission on one or more Set B beams. The first configuration information may include time and / or frequency resources, time period, frequency hopping, etc. for the transmission of the SSBs / RSs in the corresponding Set B. The WTRU may also be configured with a second set of configuration information regarding the transmission of Set A beams. That is, the WTRU may receive configurations regarding the instances where all transmission and / or estimation SSBs and / or RSs associated with Set A and / or Set B may be transmitted. The second configuration information may include time and / or frequency resources, time period, frequency hopping, and so forth for the transmission of the SSBs / RSs in the corresponding Set A. The second time period corresponding to transmission of Set A beams may be longer than the first time period corresponding to transmission of Set B beams. The WTRU may receive the first and / or second configuration information, for example via MIB, SIB, RRC, MAC-CE, and / or DCI, etc.

[0214] FIG. 3 shows an example of a system 300 with skipped SSBs. The solid-line beams 310 indicate the Set B, or the transmitted beams. The dashed-line beams 320 indicate the Set A, or the estimation beams.

[0215] Postponing beam failure detection may be based on traffic. A WTRU may have capability of predicting a blockage (e.g., a drop below a threshold in beam quality and / or RSRP for a possibly predicted finite duration), traffic status, and / or the best beam after a blockage duration is over.

[0216] The WTRU may predict a blockage on a first beam (or RS) and / or corresponding blockage time duration. The prediction may be based on at least one of: AI / ML model, and / or measurements on one or more configured first BFD-RS sets (e.g., via trained model that is based on fingerprinting at gNB).

[0217] The WTRU may predict a second beam (or RS) that may be the best beam (or RS) after the blockage is finished (e.g., a second beam per BFD-RS set). The second predicted beam (or RS) may or may not be included in the configured first BFD-RS sets. A blockage may be determined to be finished based on at least one of: predicted blockage time duration elapsing, predicted, and / or actual beam quality and / or RSRP may be higher than threshold.

[0218] The WTRU may determine and / or predict potential traffic status (e.g., for the duration of the predicted blockage). Status may include amount of traffic and / or traffic type and / or priority. The WTRU may postpone the beam failure detection and / or associated BFR in case the determined and / or predicted traffic is low priority (not urgent), the determined and / or predicted amount is less than a threshold, and / or blockage duration is shorter than a time threshold.

[0219] Regarding the WTRU and network handshake, the WTRU may indicate at least one of: the predicted blockage and / or blockage timing (e.g., start, end, and / or duration), the determined and / or predicted traffic status to gNB (e.g., prior to the start time of the blockage), whether the WTRU has determined to postpone the beam failure detection and associated BFR, and / or predicted second beam (or RS). As part of CSI report, or via separate SR. The WTRU may indicate that WTRU has predicted the blockage. Due to low traffic, the WTRU may postpone the BFR. The WTRU may indicate the BFD-RS set for which blockage is predicted. Indication may include the second predicted beam, BFR time duration to postpone (TPP_BFR), WTRU’s location, RSRP measurement of BFD-RS set for which blockage is predicted, etc.

[0220] The WTRU may receive confirmation and / or rejection and / or an enabling and / or disabling indication from gNB. If confirmed, the WTRU may receive indication on the time duration for which to postpone BFD and / or associated BFR (e.g., a postponement period), corresponding parameters, etc. The WTRU may postpone the BFD and / or associated BFR. If rejected, the WTRU may perform BFR; the WTRU may report the beam failure; and / or the US may send RACH, etc.

[0221] After the BFD and / or associated BFR postponement procedure is finished and / or one or more of the blockage time duration or the time duration to postpone BFD and / or associated BFR has elapsed, the WTRU may determine if the BFD condition still applies (e.g., based on measurements of the configuredBFD-RS sets). The WTRU may attempt to detect CORESET and / or receive PDCCH to measure the beam quality (e.g., based on PDCCH DMRS).

[0222] If the condition still applies, the WTRU may perform BFR (e.g., the WTRU reports the beam failure; and / or sends RACH, etc.) If the condition no longer applies, the WTRU may send a report to gNB. The WTRU may send an UL transmission (e.g., via SR, UCI, and / or MAC-CE, etc.) indicating that beam failure was avoided. The WTRU may report the measurements made before and / or during blockage, if any, e.g., for gNB training purposes.

[0223] A WTRU may determine and / or predict that a blockage event may occur. The prediction may be determined based on one or more of: measurements. The WTRU may perform measurements on one or more RSs configured for blockage prediction and / or configured for other purposes; WTRU location, based on current and / or predicted future location; WTRU trajectory, the WTRU may predict a blockage based on current mobility, speed, and / or direction and / or predicted future speed and / or direction; historical blockage identification, wherein a WTRU may store previous blockage determination; the WTRU may be configured with blockage information (e.g., by the gNB); AI / ML model, a WTRU may use an AI / ML model with inputs including any element in this list and / or with output a predicted blockage and / or parameters thereof.

[0224] A blockage may be predicted to be temporary or of a fixed duration. A predicted blockage and / or predicted blockage event may be defined as at least one of: one or more beam failure events. A predicted blockage may be defined as prediction that one or more beam failure events will occur consecutively. A predicted blockage may be defined as a prediction that one or more beam failure events will occur in a fixed time period. A predicted blockage may be defined as a prediction that one or more beam failure events will occur on one or more beams and / or RS (e.g., BFD-RS). A predicted blockage may be defined as a prediction that all beam measurements will be determined as beam failure events. A predicted blockage may be defined as a prediction that no beam measurements will be determined as beam failure, possibly during a period of time.

[0225] A blockage may be predicted if RSRP falls below a threshold. A predicted blockage may be defined as a prediction that one or more RSRP measurements on one or more RSs (e.g., BFD-RS) will be below a corresponding threshold. A predicted blockage may be defined as a prediction that one or more RSRP measurements on one or more RSs (e.g., BFD-RS) will be below a threshold for a period of time. A predicted blockage may be defined as a prediction that no RSRP measurements will be above a threshold, possibly in a period of time. The threshold and / or the period of time may be configurable (e.g., via RRC, MAC-CE, and / or DCI indication signaling).

[0226] A blockage may be predicted when one or more blockage conditions are satisfied. A blockage condition may include any of the elements disclosed herein. For example, a blockage condition may be defined as a blockage determination.

[0227] A blockage may be predicted by listen before talk (LBT) failure. A predicted blockage may be defined as a prediction that one or more, possibly consecutive, LBT processes will fail. A predicted blockage may be defined as a prediction that one or more LBT processes will fail in a period of time. A predicted blockage may be defined as a prediction that no LBT process will succeed, possibly in a period of time.

[0228] A WTRU may predict and / or report parameters of a predicted blockage event. The parameters of a predicted blockage event may include at least one of: a beam and / or RS set. The WTRU may predict a blockage for one or more beams and / or one or more RS sets (e.g., BFD-RS sets).

[0229] Duration may be a parameter of a blockage event. The WTRU may predict the duration of a predicted blockage. The duration may be defined as the time, number of slots, number of symbols, and / or number of subframes during which a predicted blockage may occur.

[0230] Start and / or end times may be a parameter of a blockage event. The WTRU may predict the start time, symbol, slot, subframe, and / or end time, symbol, slot, and / or subframe of a predicted blockage. The start time may be defined as when the WTRU predicts the blockage event to be declared. The end time may be defined as when the WTRU predicts that the blockage conditions will no longer be present. A WTRU may determine that a blockage condition is no longer present if a measurement is determined to not indicate beam failure and / or is above a threshold.

[0231] Measurement value or predicted measurement value may be parameters of a blockage event. The WTRU may determine a measurement value at the time of the blockage prediction. The WTRU may determine a predicted measurement during the predicted duration of blockage. The predicted measurement may be one used to determine a beam failure event. The measurement value may be defined as a range of maximum and minimum during the predicted blockage duration. The predicted measurement may be used to determine that a predicted blockage has ended. The predicted measurement value may be associated with a beam or RS for which a blockage event has been predicted. The predicted value may be associated with a beam and / or RS different from that for which a blockage event has been predicted. The WTRU may predict a best beam or best RS set (e.g., BFD-RS set and / or candidate RS set). The predicted best beam and / or best RS set may be determined based on predicted and / or actual measurements.

[0232] The predicted best beam and / or best RS set may be determined for different time instances. The best beam and / or best RS set at the time of the blockage prediction, best beam or best RS set at the time of the start of the predicted blockage, best beam or best RS set at a time during the predicted blockage duration, and / or best beam or best RS set at the end of the predicted blockage.

[0233] Prediction quality may be a parameter of a blockage event. The WTRU may determine the quality of the prediction of a predicted blockage. The quality may indicate a certainty that the predicted blockage and / or a parameter thereof has happened.

[0234] WTRU position may be a parameter of a blockage event. The WTRU position may include at least one of: WTRU position at time of blockage prediction, WTRU position at time of predicted blockage start, and / or WTRU position at time of blockage end.

[0235] A WTRU may have specific behavior upon determination of a predicted blockage. A WTRU may predict a blockage event or parameters thereof. The WTRU may be configured with transmission parameters and / or may determine or predict a transmission parameter. The transmission parameter may include at least one of: UL and / or DL data volume. The WTRU may predict, determine, and / or be configured with UL and / or DL data volume. The UL and / or DL data volume may be applicable at the time of the blockage prediction or at the predicted start time of the predicted blockage.

[0236] UL and / or DL data parameters. The WTRU may predict, determine, and / or be configured with parameters associated with the current or upcoming UL and / or DL data. The parameters may include at least one of: user plane and / or control plane, SRB and / or DRB, LCH, priority (e.g., LCH priority and / or L1 priority), QoS, delay budget, required reliability, and / or hybrid automatic request (HARQ) operating point.

[0237] The WTRU may determine a behavior to adopt when it has predicted a blockage. The behavior to adopt may include at least one of: delaying or postponing beam failure detection. A WTRU may delay or postpone BFD for a period of time. The WTRU may stop or pause BFD measurements for a period of time. The WTRU may skip beam failure measurements during the predicted blockage duration to not increment a BFI counter. The WTRU may pause and / or skip BFI counting during the predicted blockage duration. In another example, the WTRU may increase a value of a beam failure counter or timer.

[0238] The WTRU may adopt behavior for delaying and / or postponing beam failure recovery (BFR). A WTRU may delay or postpone BFR for a period of time.

[0239] The WTRU may adopt behavior to pre-emptively declare BFD and / or begin BFR. The WTRU may declare beam failure at the time of predicting the blockage, before the blockage itself happens. The WTRU may adapt the BFD parameters (e.g., counter and / or timers) such that the WTRU can confirm a predictedblockage. This may enable the WTRU to confirm a predicted blockage faster than legacy beam failure detection.

[0240] The WTRU may adopt behavior to perform beam switching. The WTRU may be configured, indicated, and / or determine to switch to a selected beam that is different from the original first beam for which the blockage is predicted. The WTRU may select to switch to a second predicted beam, a third configured beam, and / or a fourth candidate beam. The beam switch may include sending PRACH on the selected beam. The beam switch may be RACH-less. The WTRU may transmit a configured UL transmission (e.g., PUCCH, PUSCH, etc.) based on the selected beam. The WTRU may send an SR based on the spatial filter that corresponds to the selected beam.

[0241] The WTRU may adopt handover to another cell. The WTRU may be configured, indicated, and / or determine to perform a handover to a configured and / or determined second cell that is different from the first cell where the blockage is predicted.

[0242] The WTRU may adopt behavior for proceeding as regular (e.g., declaring BFD and / or starting BFR when the blockage event occurs). For example, the WTRU may be configured, indicated, and / or determine to fall back to the beam failure recovery procedures received via, e.g., RRC, MAC-CE, and / or DCI.

[0243] The WTRU may adopt behavior indicating the predicted blockage. The WTRU may send a report (e.g., to a gNB) to indicate the predicted blockage event. The WTRU may send the report as part of CSI, a separate SR, an enhanced HARQ-ACK, via, e.g., RRC, MAC-CE, and / or UCI.

[0244] The WTRU may determine what behavior to adopt upon predicting a blockage based on at least one of: one or more transmission parameters. If the volume of UL and / or DL traffic is below a threshold, the WTRU may determine to delay or postpone BFD and / or BFR. If the volume of UL and / or DL traffic is greater than a threshold, the WTRU may determine to declare BFD and / or perform BFR. If the UL and / or DL traffic is determined to have a priority greater than a possibly configurable value, then the WTRU may pre-emptively declare BFD and / or trigger BFR.

[0245] The WTRU may determine its behavior based on predicted and / or determined blockage event parameter. If the predicted duration of a blockage event is less than a threshold, the WTRU may delay and / or postpone BFD and / or BFR. If the predicted duration is greater than a threshold, the WTRU may declare BFD and / or perform BFR.

[0246] The WTRU may determine its behavior based on predicted and / or actual measurements. For example, the WTRU may determine the behavior to adopt based on actual measurements (e.g., at the timeor prior to predicting a blockage), and / or predicted measurements (e.g., predicted for any time during a blockage duration and / or after a blockage duration).

[0247] The WTRU may determine its behavior based on prediction quality. If the prediction quality and / or expected accuracy is greater than a threshold, the WTRU may select a first behavior (e.g., delaying BFD and / or BFR). If the prediction quality and / or expected accuracy is less than a threshold, the WTRU may select a second behavior (e.g., legacy BFD and / or BFR behavior).

[0248] The WTRU may use a combination of the listed methods to determine the behavior to adopt upon predicting a blockage. If the predicted blockage duration is less than a first threshold and the predicted UL and / or DL traffic is less than a second threshold, the WTRU may delay and / or postpone and / or adapt parameters of BFD and / or BFR. If the predicted blockage duration is less than a first threshold and / or the predicted UL and / or DL traffic is greater than a second threshold, the WTRU may switch beams. If the predicted blockage duration is greater than a first threshold and / or the predicted UL and / or DL traffic is less than a second threshold, the WTRU may perform legacy BFD and / or BFR. If the predicted blockage duration is greater than a first threshold and / or the predicted UL and / or DL traffic is greater than a second threshold, the WTRU may pre-emptively declare BFD and / or trigger BFR.

[0249] The WTRU may provide an indication of a predicted blockage event. A WTRU may indicate (e.g., to the gNB and / or to another WTRU), a predicted blockage event or one or more blockage parameters. The WTRU may determine to indicate a predicted blockage event based on the timing of the predicted blockage event (e.g., relative to the timing of the prediction of the blockage event). If the time difference between the time of the prediction of the blockage event and the time of the predicted blockage event is greater than a possibly configurable value, the WTRU may indicate the blockage and / or one or more blockage parameters.

[0250] A WTRU may indicate the WTRU-determined and / or WTRU-preferred behavior to use for the predicted blockage event. The WTRU may explicitly indicate the WTRU-determined behavior. The WTRU may indicate the measurements and / or triggers and / or prediction values used to determine the WTRU- preferred behavior (e.g., indicate that the predicted duration and / or predicted traffic volume are above and / or below a threshold value).

[0251] When a WTRU performs BFR (either pre-emptively and / or using legacy behavior or after a delayed and / or postponed period of time), the WTRU may indicate the cause (e.g., predicted blockage event) and / or one or more predicted blockage parameters.

[0252] The WTRU may indicate predicted preferred beams to be used during or after a predicted blockage event. The WTRU may report time duration to postpone (e.g., TPP_BFR), WTRU’s location, and / or measurement of quality parameters (e.g., RSRP) for one or more BFD-RS sets for which blockage is predicted, etc.

[0253] The indication may be transmitted in preconfigured resources (e.g., CG resources) and / or may be multiplexed onto a DG or CG grant. The WTRU may transmit the indication in at least one of: UCI, CSI report, SR, MAC CE, PRACH, and / or RRC.

[0254] The WTRU may receive acknowledgement of a predicted blockage event. After transmitting an indication of a predicted blockage event, the WTRU may monitor for the reception of an indication to determine whether the WTRU receives confirmation or rejection (e.g., from the gNB and / or other WTRU) for the WTRU-determined behavior. The WTRU may indicate that the WTRU is delaying and / or postponing BFD and / or BFR. The WTRU may monitor for (e.g., gNB) acknowledgement to do so. If the WTRU does not receive acknowledgement (e.g., from the gNB), the WTRU may assume NACK and / or may proceed using legacy methods (e.g., wait until a beam failure event is actually detected and / or then trigger BFR).

[0255] The WTRU may determine the WTRU behavior or parameters thereof, based on a received indication (e.g., from the gNB). For example, the WTRU may indicate a predicted blockage and predicted blockage parameters and may determine BFD or BFR delay parameters (e.g., duration of delay, timing of delay, behavior after period of delay) based on a received indication (e.g., from the gNB).

[0256] The WTRU may receive a rejection and / or a non-acknowledgement (e.g., from the gNB) and as such, the WTRU may not delay or postpone or pre-empt BFD or BFR. The WTRU may ignore the predicted blockage and / or predicted blockage parameters but may continue predicting future blockages. The WTRU may receive a command to deactivate blockage predictions.

[0257] The WTRU may monitor for acknowledgement (e.g., from the gNB) for example in DCI, possibly of a specific CORESET or search-space or DCI Format. The CORESET, search-space, and / or DCI format may be determined as a function of one or more predicted blockage parameters, or one or more currently configured beams, and / or TCI states or QCL indications.

[0258] A WTRU may determine and / or be configured with a period of time for which it may delay and / or postpone BFD and / or BFR. The period of time may be measured in symbols, slots, subframes, and / or in time units (e.g., ms, microsecond, etc.). The WTRU may determine, or be configured with, a WTRU behavior after the completion of the delay and / or postponement time. After the completion of the delay and / or postponement time, the WTRU may perform at least one of: determine if BFD conditions areapplicable (or still applicable) on the original beam or original set of RSs. The WTRU may have a second set of BFD parameters (e.g, counters and / or timers) to use for measurements on the original beam or RS. The second set of BFD parameters may be the same as the regular set of parameters.

[0259] After the completion of the delay and / or postponement time, the WTRU may determine if BFD conditions are applicable on a predicted second beam and / or set of RSs. The WTRU may use the regular set of BFD parameters and / or a second set of BFD parameters. After the completion of the delay and / or postponement time, the WTRU may attempt to detect a PDCCH on a CORESET to measure a beam quality (e.g., on PDCCH DMRS).

[0260] If the WTRU determines that the original beam or set of RS or one of the second beams or sets of RSs is not failing (e.g., measurements are above threshold), the WTRU may report (e.g., to the gNB) that beam failure may no longer apply after the blockage duration. The WTRU may determine and / or indicate the prediction accuracy (e.g, by comparing predicted measurements with actual measurements).

[0261] If the WTRU determines BFD on the original beam and / or set of RSs or one or more second beams or sets of RSs, the UE may declare beam failure and / or trigger BFR. The WTRU may determine and / or report the prediction accuracy of the predicted blockage and / or the measurements after the end of the predicted blockage. The report of the post-blockage event beam failure and / or prediction accuracy performance may be done by at least one of: SR, UCI, MAC CE, PUCCH, PUSCH, and / or RRC.

[0262] A WTRU may perform a handshake in postponing BFR in case of more than one BFD-RS sets. In such event, the WTRU may perform and / or be configured with one or more of the following: a WTRU may be configured with more than one BFD-RS sets. The WTRU may detects a (pre)configured number of BFIs. The WTRU may consequently determine a BFD even on a first BFD-RS set. The WTRU may determine that the second BFD-RS set is not experiencing BFD. The WTRU may determine and / or predict potential traffic status based on the first BFD-set RS. In case the determined traffic is low (not urgent), the WTRU may determine to postpone the beam failure detection and / or further BFR for the first BFD-RS set. The WTRU may be (pre)configured with a first-time duration (TPP_BFR) to postpone the BFR for the first BFD-RS set.

[0263] The WTRU may predict a second beam that may be the best beam after the postponing time duration (TPP_BFR) has lapsed. The second predicted beam may be the same or different from the beam in the configured first BFD-RS set.

[0264] Regarding performing a handshake, the WTRU may indicate that the detected BFD and / or the predicted traffic to gNB via the second BFD-RS set beams. The WTRU may send the indication as part ofCSI report or via separate SR. The WTRLI may indicate that the WTRU has detected BFD on the first BFD-RS set. The WTRU may indicate that the WTRU is going to postpone the BFR due to low traffic. The WTRU may indicate the BFD-RS set for which the BFD is detected. An indication may include the second predicted beam, time duration to postpone (TPP_BFR), WTRU’S location, RSRP measurement of BFD-RS set for which BFD is detected, etc.

[0265] A WTRU may receive confirmation and / or rejection and / or enabling and / or disabling indications from the gNB. If confirmed, the WTRU may receive indication on the time duration, mode of operation, and / or corresponding parameters, etc. The WTRU may postpone the BFR accordingly for the first BFD-RS set. If rejected, the WTRU may receive indication on the mode of operation. The WTRU may fall back to legacy BFR. In other words, the WTRU may report the beam failure (e.g., sends RACH, etc.).

[0266] After the BFR postponement procedure finishes and the configured and / or determined time has elapsed, the WTRU may determine if the BFD condition still applies for the first BFD-RS set. The WTRU may atempt to detect CORESET and / or receive PDCCH to measure the beam quality (e.g., based on PDCCH DMRS). If the condition still applies, the WTRU may fall back to legacy BFR. In other words, the WTRU may report the beam failure (e.g., sends RACH, etc.). If the condition no longer applies, the WTRU may send a report to gNB. The WTRU may send an UL (e.g., via SR, UCI, and / or MAC-CE, etc.) indicating that beam failure is raised. The WTRU may report the measurements made before and / or during blockage (e.g., for gNB training purposes).

[0267] A WTRU may be configured with one or more of the following for postponing BFR in case of more than one BFD-RS sets: configurations on more than one BFD-RS sets; threshold on the number of BFIs; threshold on the traffic status; time duration (TPP_BFR) to postpone the BFR; and an indication to predict time duration (TPP_BFR) to postpone the BFR.

[0268] The WTRU may be configured with a separate configuration information per configured BFD-RS sets. The WTRU may be configured with a first traffic level, a first time duration to postpone BFR, a first indication to enable and / or disable BFR postponing, a first MAX value and / or threshold for the number of BFIs, etc. that may correspond to the beams in the first BFD-RS set. The WTRU may be configured with a second traffic level, a second time duration to postpone BFR, a second indication to enable and / or disable BFR postponing, a second MAX value and / or threshold for the number of BFIs, etc., that may correspond to the beams in the second BFD-RS set, etc.

[0269] The WTRU may trigger a process to postpone BFR based one or more of the combinations of the following conditions: the WTRU may detects BFIs on the first BFD-RS set. If the number of detected BFIsexceeds a configured threshold, then the WTRU may trigger the process to postpone the BFR. The WTRLI may have detected a (pre)configured number of BFIs, may predict traffic status based on the first BFD-set RS. If the WTRU determines that the predicted traffic status is below a configured threshold, then WTRU may trigger the process to postpone the BFR. The WTRU may have detected a (pre)configured number of BFIs, may be configured, indicated, and / or determine a priority level, for example QoS priority level, for the traffic status based on the first BFD-set RS. If the WTRU determines that the predicted user-plane and / or control-plane functions’ priority level is low (e.g., not urgent), then WTRU may trigger the process to postpone the BFR.

[0270] [Procedures for postponing BFR] The WTRU may follow the following procedures after a trigger to postpone BFR for the first BFD-RS set: the WTRU may determine that a second BFD-RS set is not experiencing BFD, e.g., no BFI occurred, and / or the number of BFI for second BFD-RS set is below the configured second threshold. The WTRU may predict that a second beam may be the best beam after the configured postponing time duration (TPP_BFR) has lapsed. The WTRU may use a pretrained AI / ML model for the prediction of best beam after the configured postponing time has lapsed. The second predicted beam may be the same or different from the beam in the configured first BFD-RS set, e.g., the WTRU may predict a new beam from Set-A as the second predicted beam. The WTRU may also predict the best postponing time duration (e.g., TPP_BFR) to report to NW if configured by the NW.

[0271] The WTRU may initiate a handshake procedure to receive BFR decisions from the NW. The WTRU may initiate the handshake upon detecting beam failure on the first BFD-RS set. The WTRU may initiate the handshake via at least a beam from the second BFD-RS set beams. The WTRU may send the indication as part of CSI report, via separate SR, or as part of an enhanced HARQ-ACK codebook, for example via UCI, MAC-CE, RRC, etc.

[0272] The WTRU may indicate one or more of the following to the NW within the handshake feedback: the detection of a BFD; the identifier on the BFD-RS set for which BFD is detected; an approval request to postpone the BFR, due to detected beam failure and low traffic (or low priority (e.g., low QoS) traffic); if configured, the WTRU may also indicate the predicted best postponing time duration TPP_BFR; the predicted second beam to use after the postponing time has lapsed and / or the predicted metrics, e.g., predicted RSRP and / or predicted traffic; the WTRU’s speed and / or location; and / or RSRP measurement of the BFD- RS set for which the BFD is detected.

[0273] The WTRU may receive confirmation, rejection, enabling, and / or disabling indication (e.g., from gNB) to perform WTRU-determined BFR postponing. The WTRU may receive the indication via DCI, MAC- CE, and / or RRC, etc.

[0274] If the postponing of BFR is confirmed, the WTRU may receive one or more indications on the time duration (TPP_BFR). The indicated postponing time duration may be different from the time duration requested by the WTRU. If the postponing of BFR is confirmed, the WTRU may receive one or more modes of operation and / or corresponding parameters. The WTRU may postpone BFR accordingly for the first BFD-RS set. The WTRU may increase default TPP_BFR and then postpone the BFR. The WTRU may switch to the predicted second beam if BFD still applies to first BFD-RS set after the postponing time has lapsed. The WTRU may switch to an indicated third beam corresponding to second BFD-RS set if BFD still applies to first BFD-RS set after the postponing time has lapsed. The WTRU may fallback to legacy BFR if BFD still applies to first BFD-RS set after the postponing time has lapsed.

[0275] If the postponing of BFR is rejected, WTRU may be indicated to proceed with one of the following: the WTRU may switch to another beam associated with a second BFD-RS set. The WTRU may fall back to legacy BFR and / or may report the beam failure, for example by sending RACH.

[0276] If postponing BFR were allowed and / or if the WTRU postponed the BFR, the WTRU may determine if the BFD conditions still apply for the first BFD-RS set after the BFR postponement procedure is complete and / or the configured and / or determined postponing time has elapsed. The WTRU may attempt to detect CORESET and / or receive PDCCH to measure the beam quality (e.g., based on PDCCH DMRS).

[0277] If the BFR condition still applies to the first BFR-RS set, the WTRU may follow one of the procedures below. The WTRU may fall back to legacy BFR, and may report the beam failure (e.g., by sending RACH). The WTRU may switch to the second predicted beam. The WTRU may send PRACH on the second detected beam. The WTRU may detect CORESET and receive PDCCH to measure the beam quality for the second beam, and sends an UL (e.g., via SR, UCI, and / or MAC-CE, etc.) via second beam resources indicating that WTRU has switched to the second beam. The WTRU may switch to a third beam corresponding to a second BFD-RS. The WTRU may detect CORESET and / or receive PDCCH to measure the beam quality for the third beam. The WTRU may send an UL (e.g., via SR, UCI, and / or MAC- CE, etc.) via third beam resources indicating that WTRU has switched to third beam.

[0278] If the BFR condition on first BFR-RS set no longer applies, the WTRU may send a report to gNB, including one or more of the following: the WTRU may send an UL (e.g., via SR, UCI, and / or MAC-CE, etc.)indicating that beam failure is raised. The WTRU may report the measurements made before and / or during blockage (e.g., for gNB training purposes), including one or more the following: RSRP measurements on first and / or second BFD-RS set; the amount of accumulated traffic at UP, and / or CP buffer; the prediction accuracy of traffic prediction model; the prediction accuracy of postponing time prediction model; and / or WTRU’s speed, location, and / or trajectory.

[0279] The WTRU may perform selecting and / or reporting preferred BFR postponing method. A WTRU may determine and / or reports the preferred parameters to be used for postponing BFD and / or associated BFR, based on WTRU’s location with regards to the beam pattern, the measured quality of the beam, and / or prediction accuracy, etc.

[0280] A WTRU may be configured with a first set of BFR parameters, including a first BFI max counter (e.g., BFI-MAX-1), and / or a first set of BFD-RS sets, etc.

[0281] The WTRU may determine and / or receive indications to enable, allow, activate, and / or confirm to postpone BFD and / or associated BFR procedure on one or more first BFD-RS set beams (or RSs) for a first configured and / or determined time duration (e.g., TPP_BFRI).

[0282] The WTRU may predict a second (best) beam (or RS) to be used after the determine / configured time duration (TPP_BFR). The WTRU may perform the prediction (e.g., based on WTRU’s speed, direction, position, and / or AI / ML, etc.).

[0283] The WTRU may be configured with multiple parameters for BFD and / or associated BFR postponing (e.g., to extend the number of BFI counter and / or timer). The WTRU may be configured with one or more second sets of BFD and / or BFR parameters, including one or more second BFI max counters, one or more second sets of BFD-RS sets, and / or one or more-time durations to postpone the BFD and / or associated BFR.

[0284] The WTRU may select a second set of BFD and / or BFR parameters from the configured one or more second sets of BFD and / or BFR parameters, for BFD and / or associated BFR postponing (e.g., before BFD happens). The selection may be based on at least one of: accuracy of beam prediction, predicted second beam, and / or upcoming UL traffic.

[0285] The WTRU may determine acceptable accuracy for beam prediction. In case the WTRU may determine that the prediction accuracy of the second predicted beam is acceptable, that is the accuracy parameter is higher than a first threshold, then the original first BFD-RS set beam and / or predicted second beam are the same. In case the WTRU may determine that the second predicted beam is the same as the first beam, the WTRU may determine the first mode of operation as the preferred mode. This case mayhappen if the WTRU is in the center of the first beam, and / or if the WTRU moves toward the center (e.g., based on increased differential RSRP measurements).

[0286] The original first BFD-RS set beam and / or predicted second beam may be different. In case the WTRU determines that the second predicted beam is different from its first beam, then the WTRU may determine the third mode of operation as the preferred mode. This case happens if WTRU is at the cell edge of the first beam, or if it is going toward the cell edge (e.g., based on decreased differential RSRP measurements).

[0287] The WTRU may perform fair accuracy for beam prediction. In case the WTRU may determine that the prediction accuracy of the second predicted beam is fair, that is the accuracy parameter is lower than a first threshold and / or higher than a second threshold. The original first BFD-RS set beam and / or predicted second beam may be the same. In case the WTRU may determine that the second predicted beam is the same as the first beam. This case may happen if the WTRU is in the center of the first beam, or if the WTRU moves toward the center (e.g., based on increased differential RSRP measurements). The WTRU may use the first configured BFD-RS set. The WTRU may select a second BFI max counter (BFI-MAX-2) from the configured one or more second BFI max counters. The WTRU may select a second time to postpone the BFD and / or associated BFR (TPP_BFR2). During this time, the WTRU may predict the first and / or second beams to be the same based on the accuracy level.

[0288] The original first BFD-RS set beam and / or predicted second beam may be different. In case the WTRU may determine that the second predicted beam is different from its first beam. This case may happen if the WTRU is at the cell edge of the first beam, or if the WTRU moves toward the cell edge (e.g., based on decreased differential RSRP measurements). The WTRU may select a third BFI max counter (BFI-MAX-3) from the configured one or more second BFI max counters. The WTRU may select a third time to postpone the BFD and / or associated BFR (TPP_BFR3). Then, the WTRU may predict the second predicted beam to become different from the first configured BFD-RS sets based on the accuracy level. The WTRU may select a second set of BFD-RS sets from the configured one or more second sets of BFD- RS sets, e.g., based on the AI / ML model and / or the predicted second beam.

[0289] The WTRU may determine unacceptable accuracy for beam prediction. In case the WTRU may determine that the prediction accuracy of the second predicted beam is unacceptable, that is the accuracy parameter is lower than the second threshold, then the WTRU may selects a fourth BFI max counter (BFI- MAX-4) from the configured one or more second BFI max counters (e.g., where BFI-MAX-4 may be lowerthan the BFI-MAX-2 and / or BFI-MAX-3). The WTRLI may select a fourth time duration to postpone the BFD and / or associated BFR (TPP_BFR4).

[0290] The WTRU may determine upcoming UL traffic. In case the WTRU identifies one or more UL traffic (e.g., SR, and / or RACH, etc.), the WTRU may perform BFR.

[0291] The WTRU may perform reporting. The WTRU may send an indication to gNB indicating the selected second set of BFD and / or BFR parameters (e.g., in case a BFD is detected in a future time window). The WTRU may send the indication as part of CSI report (e.g., periodically), or via separate SR (e.g., semi-persistent and / or aperiodic transmission). The indication may include one or more parameters, e.g., selected BFI max counter, time duration to postpone the BFD and / or associated BFR, and / or BFD-RS sets, etc. The indication may include the validity duration of the selected second set of BFD and / or BFR parameters (e.g., after which the WTRU may fall back to the first set of BFD and / or BFR parameters). The WTRU may receive a confirmation, an adjustment of the values, and / or a rejection indication from gNB.

[0292] A WTRU may determine and / or receive one or more indications and / or configuration information that may allow, enable, confirm, and / or activate postponing BFR on or more first BFD-RS set beams for a configured, indicated, and / or determined time duration (e.g., TPP_BFR). The WTRU may be capable of predicting a second (best) beam to be used after a time duration. The WTRU may predict the second (best) beam after BFR postponing time duration (TPP_BFR). The WTRU may predict the second beam based on trained data sets (e.g., in AI / ML), WTRU’s speed, direction, position, and / or one or more beam quality measurements (e.g., RSRP), etc.

[0293] A WTRU may be configured with one or more modes of operation in postponing the BFR. The WTRU may use one or more of the following modes: first mode: hold Tx / Rx. For example, the WTRU may hold any transmission, reception, BFR, etc. as in a WTRU-oriented semi-persistent and / or aperiodic DRX and / or DTX. The second mode: extend BFD. For example, the WTRU may extend BFI counter, timer, and / or set of candidate beams, etc. The third mode: beam switching. For example, the WTRU may skip the BFR on the first beam and / or perform beam switching to a second beam. Fourth mode: the WTRU may fall back to legacy BFR.

[0294] The WTRU may determine the mode of operation to be used for postponing BFR based on one or more conditions. The WTRU may determine the mode of operation before beam failure is detected and / or before BFD is triggered. The WTRU may determine the mode of operation based on one or more of the following example conditions: accuracy of beam prediction condition. A WTRU may determine that the accuracy of the prediction for best future beam is acceptable. That is, the WTRU may determine that thatthe accuracy of one or more predicted beam resources and / or corresponding predicted quality parameters is higher than the specified, determined, and / or configured first threshold. The WTRU may determine the accuracy of predicted parameters by comparing one or more of the predicted beam resources with one or more corresponding measured parameters. In case the difference is lower than a first threshold, the WTRU may determine the accuracy to be valid and / or acceptable. When the difference is higher than the first threshold and lower than a second threshold, then the WTRU may determine the accuracy to be fair. When the difference is higher than the second threshold, the WTRU may determine the accuracy to be unacceptable and / or invalid.

[0295] The WTRU may determine the mode of operation based on predicted second beam condition. The WTRU may determine that the predicted second beam in time-domain may be the same as the beam in the first BFD-RS set or different from the beam resources in the first BD-RS set.

[0296] The WTRU may determine the mode of operation based on upcoming UL traffic condition. The WTRU may determine that there is no UL traffic scheduled and / or configured for a time duration for the time duration to postpone the BFR (e.g., TPP_BFR). The WTRU may determine that one or more UL traffic is scheduled and / or configured for the time duration to postpone the BFR (e.g., TPP_BFR). The UL traffic may include one or more of SR, RACH, PUCCH, and / or PUSCH, etc.

[0297] The WTRU may perform procedures in case of acceptable accuracy for the prediction of a future best beam. A WTRU may determine that the accuracy of the beam prediction is acceptable and / or valid. As such, the WTRU may determine the best second beam in time-domain, for example after the BFR postponing has elapsed (e.g., TPP_BFR).

[0298] A WTRU may use the first mode of operation in case the WTRU determines that the predicted second beam and the original first beam in the first BFD-RS set are the same. That is, the WTRU may use the first original beam after the BFR postponing time duration has elapsed.

[0299] For example, see FIG. 4, where the WTRU 410 (e.g., in the moving car) that is served via beam #1 420 is temporarily blocked. FIG. 4 depicts a scenario wherein beam #1 420 is temporarily blocked and a WTRU 410 is moving towards the center of beam #1 420. In this case, the WTRU 410 may determine to postpone the BFR procedure for a time duration. The WTRU 410 may predict that after the time duration has elapsed, the WTRU 410 will still be in the vicinity of beam #1 420 and could be served with beam #1 420.

[0300] In this scenario, the WTRU 410 may determine to use first mode of operation, where the WTRU 410 holds any transmission, reception, BFR, etc. for the determined and / or (pre)configured time duration.The WTRU 410 may continue operation, transmission, reception, etc. based on the first beam after the time has elapsed.

[0301] In an alternate scenario, a WTRU may determine to use the third mode of operation in case the WTRU determines that the predicted second beam is different from the original first beam. That is, the WTRU may use the second predicted beam after the BFR postponing time duration has elapsed. For example, in FIG. 5, where the WTRU 510 (e.g., in the moving car) that is being served via beam #1 520 is temporarily blocked. FIG. 5 depicts a scenario wherein beam #1 520 is temporarily blocked and a WTRU 510 is moving towards the center of beam #2 530.

[0302] In this case, the WTRU 510 may determine to postpone the BFR procedure for a time duration. The WTRU 510 may predict that after the time duration has elapsed, the WTRU may not be in the vicinity of beam #1 520. The WTRU 510 may predict that by the time the BFR postponing time duration has elapsed, the WTRU 510 may be in the vicinity of beam #2 530 and could be served with beam #2 530.

[0303] In this scenario, the WTRU may determine to use the third mode of operation. The WTRU may performs beam switching after the BFR postponing time duration has elapsed. The WTRU may send PRACH based on the second beam, and / or the WTRU may transmit one or more UL signals and / or channels based on the second beam. The UL signals and / or channels may be one or more of SRS, SR, PUCCH, and / or PUSCH, etc.

[0304] The WTRU may conduct procedures in case of “fair” accuracy for the prediction of a future best beam. A WTRU may determine to use the second mode of operation for postponing BFR in case the WTRU determines that the accuracy to predict the second beam is fair. That is, the WTRU may determine to postpone the BFR for a first determined and / or (pre)configured time duration (e.g., TPP_BFR1), during which the WTRU keeps measuring and / or monitoring configured BFD-RS sets. The WTRU may extend the MAX number to a second MAX value for detecting BFI based on the first BFD-RS set for which the blockage and / or beam failure is detected. The WTRU may measure and / or monitor a second BFD-RS set. The WTRU may monitor and / or measure a second set of candidate beams.

[0305] A WTRU may conduct procedures in case of unacceptable accuracy for the prediction of a future best beam. A WTRU may determine to use the second mode of operation for postponing BFR in case the WTRU determines that the WTRU is not able to predict the second beam and / or if the WTRU determines that the accuracy to predict the second beam is unacceptable and / or invalid. That is, the WTRU may determine to postpone the BFR for a second determined and / or (pre)configured time duration (e.g., TPP_BFR2), during which the WTRU keeps measuring and monitoring configured BFD-RS sets. Thesecond time duration may be shorter than the first-time duration. In an example, the WTRU may extend the MAX number to a third MAX value for detecting BFI based on the first BFD-RS set for which the blockage and / or beam failure is detected, where the third MAX value may be lower than the second MAX value. The WTRU may measure and / or monitor a second BFD-RS set. The WTRU may monitor and / or measure a second set of candidate beams.

[0306] A WTRU may use a short BFR postponing time duration or stop and / or cancel a BFR postponing procedure in case the WTRU identifies one or more UL traffic occasions. One or more of the following may apply: shorter BFR postponing duration. For example, the WTRU may determine the time duration to be used for BFR postponing based on the next UL traffic occasion. The WTRU may determine the time duration from when the number of detected BFI has reached MAX value till next UL traffic occasion (e.g., TUL). The WTRU may determine the time duration for the processing time for the legacy BFR operation (e.g., Tlegacy_BFR). The WTRU may subtract the legacy BFR processing time from the time till next UL occasion. The WTRU may use the resulting time duration as the time to postpone BFR (e.g., TPP_BFR = TUL - Tlegacy_BFR).

[0307] The WTRU may further determine, apply, and / or perform a beam switch. For example, the WTRU may determine that the accuracy to predict the future beam is valid. The WTRU may predict the second beam to be used by the time that next UL traffic is scheduled and / or configured. As such, the WTRU may switch to the second predicted beam to perform the scheduled and / or configured UL transmission.

[0308] The WTRU may further determine, apply, and / or perform fallback to legacy BFR. The WTRU may determine that the accuracy to predict the future beam is invalid or the WTRU is not capable to predict the second beam. As such, the WTRU may fall back to perform legacy BFR procedure. That is, the WTRU may measure one or more candidate beams and send PRACH on the selected candidate beam (e.g., with highest RSRP).

[0309] The WTRU may also perform reporting as the preferred BFR postponing method. A WTRU may perform one or more of the following: the WTRU may sends an indication to gNB indicating the preferred mode of operation for BFR postponing, in case a BFD is detected in a future time window. The WTRU may send the indication as part of CSI report (periodically), or via separate SR (semi-persistent or aperiodic transmission). The indication may include the time window, during which the indicated preferred mode of operation is valid. The indication may include one or more parameters regarding the indicated preferred mode of operation: if the first mode of operation is preferred, the DRX short and / or long cycle times may be indicated. If the second mode of operation is preferred, then the extended number of BFI and / or theextended set of monitoring BFR candidate beams may be indicated. If the third mode of operation is preferred, the predicted second beam may be indicated. The WTRU may receive a confirmation, an adjustment of the values, and / or a rejection indication from gNB.

[0310] A WTRU may transmit one or more reports and / or indications to indicate the determined mode of operation for postponing the BFR. The report may include one or more information regarding the determined mode of operation. The WTRU may transmit the report to a gNB. The WTRU may send the report and / or indications via UCI, MAC-CE, and / or RRC signaling. The indication and / or report may include one or more of the following: determined mode of operation. The WTRU may indicate the determined mode of operation via a flag indication, where a first value (e.g. , zero) may indicate a first mode, a second flag value (e.g., one) may indicate a second mode, a third flag value (e.g., two) may indicate a third mode, etc. The WTRU may report one or more indications based on the determined mode of operation:

[0311] For example, in case the WTRU may determine to use the first mode of operation, the WTRU may report the determined DRX short and / or long cycle times. For example, in case the WTRU determines to use the second mode of operation, the WTRU may report the extended number of BFI, the extended BFD- RS set, and / or the extended set of candidate beam resources, etc. In case the WTRU determines to use the third mode of operation, the WTRU may report the predicted second beam.

[0312] The indication and / or report may include time duration. For example, the WTRU may indicate the time span, during which the WTRU may apply the determined mode of operation. The WTRU may indicate the starting time, the time duration, and / or the end time. The WTRU may indicate the time duration based on time instances, number of symbols, slots, frames, and / or subframes, etc. The WTRU may indicate the time duration based on time units, for example msec, and / or micro sec, etc.

[0313] The indication and / or report may include periodicity: the WTRU may indicate if applying the determined mode of operation may take place semi-persistently, periodically, or aperiodically. The WTRU may determine the periodicity for applying the determined mode based on the detected, triggered, and / or determined conditions, for example accuracy of beam prediction, configured and / or scheduled UL and / or DL occasions, etc. as described herein.

[0314] The indication and / or report may include measured quality parameters. The WTRU may report one or more measured quality parameters, before blockage, during blockage and / or beam failure, and / or after the blockage and / or beam failure is over. The WTRU may report measured SS-RSRP, CSI-RSRP, and / or RSRP based on PDCCH DMRS, RSRP based on PDSCH DMRS, RSRP based on PBCH DMRS, etc.

[0315] The indication and / or report may include speed, location, and / or trajectory. The WTRU may report its location, speed, and / or trajectory, etc. before the blockage and / or beam failure, during the blockage and / or beam failure, and after the blockage and / or beam failure.

[0316] The WTRU may receive configurations, determine, and / or be (pre)configured with time and / or frequency resources to transmit the report and / or indications. The WTRU may be configured and / or determined to transmit the report before or after applying the determined mode of operation. In such case, one or more of the following may apply: an indication before applying the determined mode. A WTRU that predicts a blockage may determine to postpone the BFR based on one or more conditions, as described herein. The WTRU may be (pre)configured and / or determine to transmit the report before being blocked and as soon as detecting one or more conditions and / or receiving the triggers on the future blockage. The WTRU may determine to transmit the report before blockage, if there is a long enough time window between detecting the conditions and / or receiving the triggers and the blockage and / or beam failure.

[0317] In case the WTRU is configured with more than one BFD-RS sets, the WTRU that has detected beam failure based on a first BFD-RS set and / or the WTRU that has predicted blockage based on a first BFD-RS set, may use one or more beam resources from a configured second BFD-RS set to send the report and / or indication.

[0318] The WTRU may be (pre)configured or determine to send the report as part of a (pre)configured CSI report. The WTRU may transmit a (special) scheduling request (SR), for example via (pre)configured PUCCH resources. As such, the WTRU may transmit the determined mode of operation and / or corresponding information as part of the transmitted SR.

[0319] The WTRU may be configured and / or determined to send an indication after postponing the BFR based on determined mode. The WTRU may be (pre)configured and / or determined to transmit the report after postponing the BFR and after applying the determined mode. In such case, one or more of the following may apply: implicit indication: the WTRU may indicate postponing the BFR by transmitting the configured and / or scheduled UL after the postponing time duration has elapsed. The WTRU may use (pre)configured UL resources configured for a special SR transmission. As such, the gNB may realize that WTRU had held any transmission due blockage and / or beam failure detection based on BFR postponing procedure. The gNB may realize that the WTRU is no longer experiencing blockage and / or beam failure detection.

[0320] After applying the determined mode, the WTRU may transmit an explicit indication: the WTRU may transmit the report and / or indication via one or more explicit indications. One or more of the following mayapply to the explicit indications: via UCI and / or MAC-CE: for example, the WTRU may send the report as part of UCI and / or MAC-CE associated with one or more configured and / or scheduled UL transmission. The WTRU that is scheduled to transmit a PUCCH may include the report as part of the transmitted UCI. The WTRU that is scheduled to transmit a PUSCH may include the report as part of the transmitted MAC- CE.

[0321] HARQ-ACK may be part of the explicit indication: For example, the WTRU may send the report as part of HARQ-ACK transmission that is associated with at least a received PDCCH after the blockage is over, the beam failure is over, and / or after the BFR postponing time duration has elapsed. The WTRU may transmit an enhanced HARQ-ACK codebook, where the codebook may include a (flag) indication to indicate whether the WTRU has postponed the BFR. Wherein, a first value (e.g., zero) may indicate BFR postponing, and / or a second flag value (e.g., one) may indicate no BFR postponing.

[0322] After sending the report, the WTRU may receive a confirmation, one or more adjustment commands on one or more parameters for BFR postponing. The WTRU may receive a rejection indication (e.g., from a gNB), wherein the WTRU may not perform BFR postponing and / or may fallback to legacy BFR procedure.

Claims

CLAIMSWhat is claimed is:1 . A wireless transmit / receive unit (WTRU) comprising: a processor configured to: determine a blockage of a first beam and a time duration associated with the blockage of the first beam; determine to postpone beam failure detection (BFD) or beam failure recovery (BFR) when an amount of data associated with the first beam is less than a first threshold, a priority of the data associated with the first beam is less than a second threshold, or the time duration associated with the determined blockage of the first beam is shorter than a third threshold; and send, to a network, a first report comprising one or more of an indication of the determined blockage, an indication of the time duration associated with the determined blockage of the first beam, an indication of the amount of data associated with the first beam, a priority of the data associated with the first beam, an indication that BFD or BFR is postponed, or an indication that a second beam has been selected.

2. The WTRU of claim 1 , wherein the WTRU determines the blockage of the first beam via an artificial intelligence or machine learning (AI / ML) model.

3. The WTRU of claim 1 , wherein the processor is further configured to: determine that the blockage still exists after the time duration expires via an artificial intelligence or machine learning (AI / ML) model; and perform BFR based on the determination that the blockage still exists after the time duration expires.

4. The WTRU of claim 1 , wherein the processor is further configured to: determine that the blockage does not exist after the time duration expires; and send, to the network, a second report based on the determination that the blockage does not exist after the time duration expires, wherein the second report comprises an indication that the blockage does not exist.

5. The WTRU of any of claims 1 to 4, wherein the processor is configured to:select the second beam based on a determination that the second beam has beam measurement and / or prediction value greater than the first beam.

6. The WTRU of any of claims 1 to 5, wherein the first report further comprises one or more of a start time of the time duration or an end time of the time duration.

7. The WTRU of any of claims 1 to 6, wherein the processor is configured to: determine the amount of data associated with the first beam prior to a start time of the blockage.

8. The WTRU of any of claims 1 to 7, wherein the processor is configured to: receive an indication from the network, wherein the indication comprises a confirmation or a rejection to postpone BFD or BFR.

9. The WTRU of claim 8, wherein the processor is configured to: receive, from the network, an indication of a postponement period, wherein the indication of postponement period is based on the indication comprising a confirmation to postpone BFD or BFR, wherein the postponement period indicates how long to postpone BFD or BFR.

10. The WTRU of claim 8, wherein the processor is configured to: perform BFR based on the indication from the network comprising the rejection to postpone BFD or BFR.

11. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: determining a blockage of a first beam and a time duration associated with the blockage of the first beam; determining to postpone beam failure detection (BFD) or beam failure recovery (BFR) when an amount of data associated with the first beam is less than a first threshold, a priority of the data associated with the first beam is less than a second threshold, or the time duration associated with the determined blockage of the first beam is shorter than a third threshold; andsending, to a network, a first report comprising one or more of an indication of the determined blockage, an indication of the time duration associated with the determined blockage of the first beam, an indication of the amount of data associated with the first beam, a priority of the data associated with the first beam, an indication that BFD or BFR is postponed, or an indication that a second beam has been selected.

12. The method of claim 11 , wherein the WTRU determines the blockage of the first beam via an (AI / ML) model.

13. The method of claim 11 , wherein the processor is further configured to: determining that the blockage still exists after the time duration expires an artificial intelligence or machine learning (AI / ML) model; and performing BFR based on the determination that the blockage still exists after the time duration expires.

14. The method of claim 11 , further comprising: determining that the blockage does not exist after the time duration expires; and sending, to the network, a second report based on the determination that the blockage does not exist after the time duration expires, wherein the second report comprises an indication that the blockage does not exist.

15. The method of any of claims 11 to 14, further comprising: selecting the second beam based on a determination that the second beam has cell measurement value greater than the first beam.

16. The method of any of claims 11 to 15, wherein the first report further comprises one or more of a start time of the time duration or an end time of the time duration.

17. The method of any of claims 11 to 16, further comprising: determining the amount of data associated with the first beam prior to a start time of the blockage.

18. The method of any of claims 11 to 17, further comprising: receiving an indication from the network, wherein the indication comprises a confirmation or a rejection to postpone BFD or BFR.

19. The method of claim 18, further comprising: receiving, from the network, an indication of a postponement period, wherein the indication of postponement period is based on the indication comprising a confirmation to postpone BFD or BFR, wherein the postponement period indicates how long to postpone BFD or BFR.

20. The method of claim 18, further comprising: performing BFR based on the indication from the network comprising the rejection to postponeBFD or BFR.

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