Beam failure detection and recovery associated with NES cells

Abstract

Systems, methods, and devices for beam failure detection and recovery are disclosed. A wireless transmit / receive unit (WTRU) receives configuration information (including an uplink indication configuration) for a first cell. If a beam failure detection counter value exceeds a first threshold and is below a second threshold (associated with beam failure detection), the WTRU may transmit a pre-beam failure indication to a network node. The network node may respond with an indication for one or more on- demand synchronization signal block (SSB) transmissions, recovery beams, or failure detection resources (FDRs). The WTRU may measure reference signals (RSs) in the transmissions and send a transmission to the network node based on the measurements.

Description

BEAM FAILURE DETECTION AND RECOVERY ASSOCIATED WITH NES CELLSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Patent Application No. 63 / 549,013 filed February 2, 2024, the contents of which are hereby incorporated by reference herein.BACKGROUND

[0002] Mobile communications using wireless communication continue to evolve. A fifth generation of mobile communication radio access technology (RAT) may be referred to as 5G new radio (NR). A previous (legacy) generation of mobile communication RAT may be, for example, fourth generation (4G) long term evolution (LTE).SUMMARY

[0003] Systems, methods, and instrumentalities are provided that are associated with beam failure detection and recovery. A wireless transmit / receive unit (WTRU) may be configured to receive configuration information associated with a first cell. The configuration information may include an uplink indication configuration to provide a pre-beam failure indication. The WTRU may determine that a beam failure detection counter value exceeds a first threshold and is less than a second threshold. The second threshold may be associated with beam failure detection. The WTRU may transmit to a network node, based on the determination that the beam failure detection counter value exceeds the first threshold and is less than the second threshold, a pre-beam failure indication. The WTRU may receive, from the network node, an indication associated with network transmissions. The network transmissions may include one or more of a sweep of on-demand synchronization signal block (SSB) transmissions, recovery beams, or failure detection resources (FDRs). The WTRU may measure reference signals (RSs) associated with the network transmissions (e.g., the WTRU may perform respective measurements of respective RSs). The WTRU may send, to the network node, a transmission based on the measurements of the RSs.

[0004] The transmission sent to the network node may include an indication that indicates that an on- demand sweep is no longer needed. The WTRU may determine that the on-demand sweep is no longer needed based on a determination that the measurements of the RSs or on-demand SSB transmissions satisfy a third threshold.

[0005] The WTRU may select a recovery beam based on the measurements of the RSs. The selected recovery beam may be associated with a measurement of an RS being greater than or equal to a fourththreshold. The RS may be one of the RSs. The transmission may include an indication of the selected recovery beam. The transmission sent to the network node may be sent based on the beam failure detection counter value exceeding the second threshold.

[0006] The network transmissions may include one or more of the following: identifiers of candidate recovery beams to be transmitted, a time duration within which the candidate recovery beams will be transmitted, time and frequency parameters associated with the transmission of the recovery beams, an indication of a bandwidth part (BWP) to be used, or an indication indicating that the WTRU is to transmit an indication based on recovery beams no longer being needed. The configuration information may include one or more of a set of FDRs for beam failure detection or a set of recovery beams for beam failure recovery.

[0007] Systems, methods, and instrumentalities are provided that are associated with beam failure detection and recovery. A wireless transmit / receive Unit (WTRU) may be configured to receive configuration information associated with a first cell (e.g., an Scell). The WTRU may send a pre-beam failure (pre-BF) indication associated with the first cell to a network node based on a beam failure detection counter being between a first threshold and a second threshold. The beam failure detection counter may be associated with the first cell. The WTRU may receive, from the network node, information associated with multiple recovery beams for the first cell. Based on the received information, the WTRU may determine (e.g., take) multiple measurements associated with the multiple recovery beams.

[0008] The WTRU may select a recovery beam from the plurality of recovery beams based on the multiple measurements. The recovery beam may be selected based on a measurement associated with the selected recovery beam from the multiple measurements being greater than or equal to a quality threshold. The WTRU may send an indication to the network node. The configuration information associated with the first cell may include a set of failure detection resources (FDR) for beam failure detection and the multiple recovery beams.

[0009] The information associated with the multiple recovery beams for the first cell may include information associated with one or more of a candidate recovery reference signals (RS), a sweep duration, a burst start timing, a burst periodicity, a frequency band start, or a flag associated with transmission of an indication that recovery beams are not needed.

[0010] On a condition that the beam failure detection counter is equal to or above the second threshold, the WTRU may transmit the indication using a second cell (e.g., an SpCell). The indication may include a beam failure detection (BFD) control element (CE) that indicates the selected recovery beam. On a condition that the beam failure detection counter resets and a reference signal received power (RSRP) ofthe first cell exceeds a threshold associated with the RSRP, the indication may indicate that recovery beams are not needed. The first cell may include an Scell.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0012] 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;

[0013] FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (ON) that may be used within the communications system illustrated in FIG. 1 A according to an embodiment;

[0014] FIG. 1 D is a system diagram illustrating a further example RAN and a further example ON that may be used within the communications system illustrated in FIG. 1A according to an embodiment; and

[0015] FIG. 2 illustrates a time-frequency structure of a synchronization signal block (SSB).

[0016] FIG. 3 illustrates an SSB beam sweeping within SSB burst sets.

[0017] FIG. 4 illustrates a failure resource and recovery beams.

[0018] FIG. 5 illustrates a WTRU anticipated beam failure (BF) indication upon missing an SSB adaptation (NES) indication.

[0019] FIG. 6 illustrates a WTRU anticipating BF after a cell applying spatial NES adaptation.DETAILED DESCRIPTION

[0020] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), 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.

[0021] 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 ON 106 / 115, a public switched telephonenetwork (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.

[0022] 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 Internet 110, and / or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node 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.

[0023] 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, e.g., 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.

[0024] 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).

[0025] 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).

[0026] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0027] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using New Radio (NR).

[0028] 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).

[0029] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi), IEEE 802.16 (e.g., 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0036] 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.

[0037] 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 moretransmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0038] 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.

[0039] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 118 may also output user 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).

[0040] 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.

[0041] 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.

[0042] 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, asatellite 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.

[0043] 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 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)).

[0044] FIG. 1 C 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.

[0045] 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.

[0046] 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.

[0047] 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 theforegoing 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.

[0048] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] In representative embodiments, the other network 112 may be a WLAN.

[0054] 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 APto be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and / or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11 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.

[0055] 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 STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0056] 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.

[0057] 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).

[0058] Sub 1 GHz modes of operation are supported by 802.11af 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, and802.11 ac. 802.11 af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11 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).

[0059] WLAN systems, which may support multiple channels, and channel bandwidths, such as802.11 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.

[0060] 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 for802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0061] 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.

[0062] 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).

[0063] 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., including varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0064] 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.

[0065] 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 plane information 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0070] 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 theWTRUs 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.

[0071] 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-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0072] 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 perform testing using over-the-air wireless communications.

[0073] The one or more emulation devices may perform the one or more, including all, functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0074] Features described herein may be associated with beam failure detection and recovery in NES Cells.

[0075] Upon detecting an anticipated beam failure for a cell x, a WTRU may transmit an indication to the network. The indication may serve as a request for on-demand failure detection resources to avoid beam failure or on-demand candidate recovery resources to recover to suitable neighboring beam(s).

[0076] A WTRU may be configured to perform beam failure detection for a cell x by monitoring and measuring signals transmitted by cell x and another related cell y. The WTRU may be configured to increment BFLCounter for cell x in a weighted manner over beam failure instances generated over signal measurements where the signals are transmitted by cell x and cell y.

[0077] A WTRU may be configured with multiple BFD configurations for different network energy savings (NES) states. The WTRU may provide an indication to the network if the measurements made over currently active failure detection resources according to the WTRU known / assumed NES state satisfy conditions. The network may respond by providing the correct NES state or on-demand measurement resources to the WTRU.

[0078] Modifications may be associated with enabling a network to minimize its power consumption from transmission and reception. Such minimization may be beneficial for reducing operational costs and environmental sustainability.

[0079] Transmissions may be minimized from the network when there is no data. For example, always- on cell-specific reference signal (CRS) may not be used in new radio (NR). Energy consumption may be reduced.

[0080] For example, the network may consumes energy when not transmitting from other activities such as baseband (digital) processing for reception or beamforming. Such “idle” power consumption may not be negligible in dense networks when no WTRU is served during a given period. If the network can turn off the activities when not transmitting to a WTRU, energy consumption may be reduced.

[0081] NR may or may not require transmission of always-on synch or reference signals and supports adaptable bandwidth and multiple input multiple output (MIMO) capabilities. Adaptation of network resources may enable efficiency in operating newer deployments and later generations.

[0082] The following terminology may be used herein. Channel state information (CSI) may include at least one of the following: channel quality index (CQI), rank indicator (Rl), precoding matrix index (PMI), an L1 channel measurement (e.g., reference signal received power (RSRP) such as L1-RSRP, or SINR), CSI- Reference Signal (RS) (CSI-RS) resource indicator (CRI), synchronization signal (SS) / PBCH block resource indicator (SSBRI), layer indicator (LI) and / or another measurement quantity measured by the WTRU from the configured CSI-RS or SS / PBCH block. 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 synchronization signal block (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-SINR taken from SSB or CSI-RS (e.g., cri-RSRP, cri-SINR, ssb-lndex-RSRP, ssb-lndex-SINR), and channel state information, such as at least rank indicator (Rl), channel quality indicator (CQI), precoding matrix indicator (PMI), Layer Index (LI), and / or the like.

[0083] Uplink control information (UCI) may include CSI, hybrid automatic repeat request (HARQ) feedback for one or more HARQ processes, Scheduling request (SR), Link recovery request (LRR), configured grant (CG)-UCI and / or other control information bits that may be transmitted on the PUCCH or PUSCH.

[0084] Channel conditions may include conditions relating to the state of the radio / channel, which may be determined by the WTRU from: a WTRU measurement (e.g., L1 / SINR / RSRP, CQI / modulation and coding scheme (MCS), channel occupancy, received signal strength indicator (RSSI), power headroom, exposure headroom), L3 / mobility-based measurements (e.g., RSRP, RSRQ, s-measure), an radio link monitoring (RLM) state, and / or channel availability in unlicensed spectrum (e.g., whether the channel is occupied based on determination of a listen-before-talk (LBT) procedure or whether the channel is deemed to have experienced a consistent LBT failure). A PRACH resource may include a PRACH resource (e.g., in frequency), a PRACH occasion (RACH occasion (RO)) (e.g., in time), a preamble format (e.g., in terms of total preamble duration, sequence length, guard time duration and / or in terms of length of cyclic prefix) and / or a certain preamble sequence used for the transmission of a preamble in a random access procedure.

[0085] A property of scheduling information (e.g., an uplink grant or a downlink assignment) may include of at least one of the following: a frequency allocation; an aspect of time allocation, such as time instance or / and a time duration; A priority; A modulation and coding scheme; A transport block size; A number of spatial layers; A number of transport blocks to be carried; A TCI state or SRI; A number of repetitions; Whether the grant is a configured grant type 1 (e.g., WTRU immediately using the configured uplink (UL) resources after receiving the configuration information), type 2 (e.g., WTRU waiting until an explicit MAC control element (CE) indication before using the configured UL resources) or a dynamic grant.

[0086] An indication by downlink control information (DCI), or an indication, may include of at least one of the following: An explicit indication by a DCI field or by radio network identifier (RNTI) used to mask cyclic redundancy check (CRC) of the PDCCH. An implicit indication by a property such as DCI format, DCI size, Coreset or search space, aggregation level, identity of first control channel resource (e.g., index of first CCE) for a DCI, where the mapping between the property and the value may be signaled by radio resource control (RRC) or MAC. An explicit indication by a downlink (DL) MAC CE.

[0087] The terms network availability state, cell turned off, cell discontinuous transmission (DTX) mode / configuration, or NES state may be used interchangeably. The WTRU may determine a cell DTX / discontinuous reception (DRX) state implicitly from a determined active availability state, and visa-versa.

[0088] The term Special Cell (SpCell) may refer to the PCell (Primary Cell) if case the WTRU is in single connectivity (e.g., WTRU is connected to one (e.g., only one) gNB and configured with one cell group configuration). In examples of dual connectivity operation (e.g., WTRU connected to two gNBs and configured with two cell groups, a group including one or more cells), SpCell may refer to the PCell of the master cell group (MCG) or the PSCell (Primary Secondary Cell) of the SCG (Secondary Cell group). A Special Cell may support PUCCH transmission and contention-based Random Access and may be activated.

[0089] The term Secondary Cell (SCell) may refer to cells within a cell group other than the SpCell. [Notation]: Hereinafter, a, an, and similar phrases are to be interpreted as one or more, or at least one. A term which ends with the suffix (s) may be interpreted as one or more or at least one. The term may, may be interpreted as may, for example.

[0090] A symbol / (e.g., forward slash) may be used herein to represent and / or, where for example, A / B may imply A and / or B.

[0091] Examples described herein may be associated with a beam. A WTRU may transmit or receive a physical channel or reference signal according to at least one spatial domain filter. The term “beam” may be used to refer to a spatial domain filter.

[0092] The WTRU may transmit a physical channel or signal using the same spatial domain filter as the spatial domain filter used for receiving an RS (such as CSI-RS) or a SS block. The WTRU transmission may be referred to as a target, and the received RS or SS block may be referred to as a reference or a source. In examples, the WTRU may transmit the target physical channel or signal according to a spatial relation with a reference to such RS or SS block.

[0093] The WTRU may transmit a first physical channel or signal according to the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel or signal. The first and second transmissions may be referred to as a target and a reference (or a source), respectively. In examples, the WTRU may transmit the first (target) physical channel or signal according to a spatial relation with a reference to the second (reference) physical channel or signal.

[0094] A spatial relation may be implicit, configured by RRC or signaled by MAC CE or DCI. For example, a WTRU may implicitly transmit PUSCH and demodulation reference signal (DM-RS) of PUSCH according to the same spatial domain filter as a sounding reference signal (SRS) indicated by an SRI indicated in DCI or configured by RRC. In examples, a spatial relation may be configured by RRC for an SRS resource indicator (SRI) or signaled by MAC CE for a PUCCH. Such spatial relation may also be referred to as a beam indication.

[0095] The WTRU may receive a first (target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (reference) downlink channel or signal. Forexample, such association may exist between a physical channel such as PDCCH or PDSCH and its respective DM-RS. At least when the first and second signals are reference signals, such association may exist when the WTRU is configured with a quasi-colocation (QCL) assumption type D between corresponding antenna ports. Such association may be configured as a TCI (transmission configuration indicator) state. A WTRU may be indicated an association between a CSI-RS or SS block 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.

[0096] Herein, an SSB may refer to one or more SSB beam (spatial relation) within a collection of SSBs (SSB burst). An SSB may refer to a beam -and visa-versa- or a CSI-RS resource related to the beam. SSB, SSBs, and / or SSB burst may refer to one or more beams transmitted from a transmission / reception point (TRP) or a TRP.

[0097] A TRP (e.g., transmission and reception point) may be interchangeably used with one or more of TP (transmission point), RP (reception point), RRH (radio remote head), DA (distributed antenna), BS (base station), a sector (of a BS), and a cell (e.g., a geographical cell area served by a BS). Hereafter, Multi-TRP may be interchangeably used with one or more of MTRP, M-TRP, and multiple TRPs.

[0098] Features described herein may be associated with cell DTX and cell DRX. The gNB may use reduced downlink transmission / uplink reception activity without an explicit cell DTX / DRX pattern with restrictions due to WTRU DRX configurations and any configured transmission / reception, e.g., common channels / signals. Connected mode discontinuous reception (C-DRX) is configured per WTRU. The alignment of the DRX cycles or offsets for different WTRUs may be done (e.g., only) via RRC. During WTRU DRX off period, the WTRU may not expect to monitor PDCCH, and the WTRU may be allowed to initiate UL transmission according to the configured resources (e.g., using PUCCH, random access channel (RACH), SR, or CG-PUSCH). Aligning / Omitting of DRX patterns across multiple UE’s may be achieved via gNB implementation.

[0099] Cell DTX / DRX may aim at providing mechanisms informing WTRU whether the cell stays inactive, which may include modifications to WTRU DRX configuration, e.g., to align / omit DRX cycles or start offsets of DRX, for WTRUs in connected mode or idle / inactive mode, (e.g., potentially) allowing longer opportunities for cell inactivity. During a cell DTX / DRX, the cell may have no transmission / reception or (e.g., only) keep limited transmission / reception. For example, the cell may not need to transmit or receive some periodic signals / channels, such as common channels / signals or WTRU specific signals / channels [1].

[0100] Cell DTX / DRX may be applied to at least WTRUs in RRC_CONNECTED state. A periodic Cell DTX / DRX (e.g., active and non-active periods) may be configured by gNB via WTRU-specific RRC signaling per serving cell. Cell DTX / DRX mode may be activated / de-activated via dynamic L1 / L2 signalingand UE-specific RRC signaling. Both WTRU specific and common L1 / L2 signaling may be considered for activating / deactivating the Cell DTX / DRX mode [1]. Cell DTX and Cell DRX modes may be configured and operated separately (e.g., one RRC configuration set for DL and another for UL). Cell DTX / DRX may be configured and operated together. At least the following parameters may be configured per Cell DTX / DRX configuration: periodicity, start slot / offset, on duration [1], In examples, Cell DTX indication may be part of system information (SI) update or system information block (SIB) signaling. There may be a common time for (e.g., all) WTRUs to determine cell DTX status.

[0101] The WTRU may be configured with multiple cell DRX and / or cell DTX configurations simultaneously in a given serving cell. The WTRU may be configured with a primary or a default cell DTX and / or cell DRX configuration, which the WTRU may apply by default. Upon reception of signaling activating one cell DTX and / or cell DRX configuration, the WTRU may deactivate another one (or all other ones). Upon reception of signaling deactivating one cell DTX and / or cell DRX configuration, the WTRU may activate another one or activate a default cell DTX / DRX configuration. Upon expiry of a timer, the WTRU may fall back to the default cell DRX and / or cell DTX configuration. The WTRU may reset such timer upon reception of DL signaling or data or an indication from the NW to remain in a given non-default cell DTX or cell DRX state.

[0102] Features described herein may be associated with network availability states / cell DTX mode / NES states. Herein, a NES state or an availability state may refer to a cell state in which the cell or TRP has activated at least one NES technique, including: cell DTX, cell DRX, spatial domain adaptation (where a subset of antenna ports and / or elements are turned off), power domain adaptation (where a subset of channels are transmitted with reduced power or muted), and / or the cell or TRP has turned off.

[0103] The WTRU may determine whether it can transmit or receive on certain resources depending on a network availability state, which implies the gNB’s power savings status. An availability state may correspond to a network energy savings state, a cell DTX mode, a cell DRX mode, and / or a gNB activity level. An availability state may be uplink or downlink specific, and may change from symbol to symbol, slot to slot, frame to frame, or on longer duration granularity. The availability state may be determined by the WTRU or indicated by the network. An availability state may be, for example, “On”, “DL and UL active”, “UL only active”, “off”, “reduced Tx power”, “dormant”, “micro sleep”, “light sleep”, or “deep sleep”. Such states may be abstracted by NW configuration parameters and / or values, and dynamic indication may point to the active availability state (e.g., by DCI or MAC CE signaling). The “Off” availability state may imply that the gNB’s baseband hardware is completely turned off. The “sleep” availability state may imply that the gNB wakes up periodically to transmit certain signals (e.g., presence signals, synchronization, or reference signals) or receive certain UL signals. In availability states, DL or UL resources may not be available duringcertain periods of time, which may enable the network to turn off baseband processing and other activities. For example, the WTRU may be configured by RRC with periodic Active and Inactive periods per availability. Measurement resources (e.g., SSBs or CSI-RS) may (e.g., only) be made available in certain availability states, including: RLM, BFD, radio resource management (RRM) measurements, CSI-RS feedback configuration, and / or a different power offset for CSI feedback.

[0104] Under conditions, the WTRU may further transmit a request to the network (wake-up request) to modify the availability state to a state for which resources that would satisfy WTRU requirements are available.

[0105] The WTRU may determine an availability state from reception of availability state indication from e.g., by L1 / L2 signaling (e.g., a group common DCI or indication), or implicitly determine it form the reception of periodic DL signaling -or lack thereof-.

[0106] The WTRU may determine if a resource is available for transmission / reception and / or measurements for the determined network availability state if it is applicable in the active availability state. The WTRU may also adapt its active C-DRX cycle, active spatial elements (e.g., antenna or logical ports), active TRPs, paging occasions as a function of the signaled or determined availability state. The WTRU may be configured with one or more sets of NES transmission and / or reception parameters per availability state, e.g., by broadcast or dedicated configuration signaling. The WTRU may apply the NES parameter set according to the determined or signaled availability state. The WTRU may apply one or more applicable configurations depending on the determined NES state. A set of NES parameter may include: a number of antenna ports, a C-DRX configuration, a measurement configuration (e.g., for RRM, RLM, and / or BFD), CSI feedback, a CSI-RS configuration, an SSB configuration, CHO or mobility candidates, and / or a set of active TRPs.

[0107] An availability state may be applicable to at least one transmission, reception, or measurement resource. An availability state may be applicable to at least one time period such as a time slot or time symbol. An availability state may be applicable to a serving cell, a cell group, a frequency band, a bandwidth part, a TRP, a set of spatial elements, or a range of frequencies within a bandwidth part. For example, when an NES state changes in a cell, the WTRU may receive an availability state change indication indicating that The change is for that cell, for all cells at the same frequency, or / and same RAT.

[0108] The WTRU may consider the active availability state associated with a cell, carrier, TRP, or frequency band to be “Off,” “Deep sleep”, or “Micro sleep” after reception of a DL signaling that changes the cell’s or TRP’s availability state. For example, the WTRU may receive a turn off command on broadcast signaling, RRC signaling, DCI (e.g., a group common DCI), or a DL MAC CE (e.g., indication part of PDSCH). The WTRU may determine an availability state from reception of availability state indication frome.g., by L1 / L2 signaling (e.g., a group common DCI or indication) or broadcast signaling associated with an availability state.

[0109] For example, an availability state change indication may be part of SI update or SIB signaling (e.g., in a separate SIB that is not read by WTRUs). There may be a common time for (e.g., all WTRUs in the cell to determine availability state status.

[0110] For example, the WTRU may determine a change of NES state change from the reception of a group common command L1 signaling (e.g., a group common DCI, a multi-stage DCI, a specific DCI format, or a DCI scrambled by a configured or specified NES-specific RNTI). L1 signaling may indicate one of the configured NES parameters sets to apply or may determine a delta configuration from the current set of parameters upon determining an NES state change. The WTRU may transmit feedback / acknowledgment to gNB, possibly multiplexed with UL data (e.g., part of an UL transport block (TB) as a MAC CE or a subheader indication), following the reception of an NES state change indication. For example, the WTRU may determine a change of NES state change from the reception of broadcast signaling associated with NES state indication or change, including signaling in SIB(s) or part of a broadcast or multicast PDSCH. The WTRU may be indicated by the NES state explicitly in the SIB. The WTRU may be configured with one or more SIBs exclusively associated with configuration of NES parameters. The WTRU may be configured to receive the broadcast or multicast indication periodically; the WTRU may determine an indication is mis-detected if not received on expected periodic occasions, if a number of misdetections is counted, and / or if a timer has elapsed since the last reception of the NES state indication. The WTRU may start inter-cell, inter-frequency, and / or inter-RAT measurements, start a mobility procedure, and / or start evaluating configured CHO candidates following the determination of a misdetection of the NES state indication.

[0111] The WTRU may implicitly assume a certain availability state associated with a cell, carrier, TRP, or frequency band (e.g., “Off, “deep sleep”, “micro sleep” or dormant”) from at least one of the following.

[0112] The WTRU may implicitly assume a certain availability state from a reception of a command or signal indicating a change in availability state: e.g., a group common DCI in connected mode or RRC signaling or a presence signal. The WTRU may determine an availability state implicitly form the reception of periodic DL signaling. The WTRU may be configured or specified to associate an availability state with one or more DL signal type (e.g., SSB, partial SSB, and / or one or more periodicity.

[0113] The WTRU may implicitly assume a certain availability state from a reception of a paging message, paging DCI, paging PDSCH, or a paging related signal (e.g., (paging early indication) PEI), possibly on a subset of paging occasions (Pos) (e.g., those aligned with NES drx cycle or a configured subset of PDCCH resources). The WTRU may assume a certain availability state after reception of an indication part of the DCI or PDCCH scheduling paging (e.g., as a function of the P-RNTI, NES-RNTI orbased on receiving an explicit indication -e.g., on a reserved bit). The WTRU may assume a certain availability state after the reception of a paging message with a certain P-RNTI, a separately configured NES P-RNTI, or the NES group RNTI. The WTRU may assume a certain availability state after the reception of a paging message with a certain P-RNTI. The WTRU may be configured with one more PEI subgroup for NES, where a subgroup may be associated with one or more availability state. The WTRU may assume a certain availability state after reception of a PEI with an NES subgroup, if that subgroup is configured and / or associated with the availability state. The indication of the availability state or the availability state switch may be indicated in the paging payload, e.g., as a flag part of the paging message or the short message. Such paging indication may further indicate an alternative cell to monitor paging on while the cell from which the signaling was received is off, sleep, or in NES state. Such paging indication may further indicate or signal applicable reconfiguration parameters (e.g., for initial access, applicable physical random access channel (PRACH) resources, applicable SSB / RS occasions, applicable SI cycle, and / or the applicable cell(s) and associated availability states).

[0114] The WTRU may implicitly assume a certain availability state from a gNB DTX status (whether the gNB is in active time or an associated activity timer is running). The WTRU may implicitly assume a certain availability state from a lack of detection of a presence indication: The WTRU may determine an availability state associated with the cell (e.g., “off or “deep sleep”) if presence indication was not detected on one or more presence indication occasion. The WTRU may assume or change the cell’s availability state after a number of consecutive misdetections or after timer expires following no detection of a presence signal. The WTRU may determine an availability state is active or de-active after expiry of a timer associated with the availability state. Such timer may be configured and / or maintained in connected mode (e.g., only), or in other states (e.g., idle and inactive states).

[0115] The WTRU may determine an availability state implicitly form the lack of reception of periodic DL signaling. For example, the WTRU may be configured with a signal quality threshold (e.g., an RSRP threshold), and if the WTRU does not detect a signal associated with an availability state (e.g., a presence signal or an SSB) with a signal strength above the threshold, the WTRU may assume that The availability state may not be active and may assume a different availability state. The criterion may be coupled with lack of detection of an identifying sequence of the presence signal (e.g., detection of the primary synchronization signal (PSS) sequence for example).

[0116] The WTRU may implicitly assume a certain availability state based on time in the day. The WTRU may be configured to automatically assume a certain availability state (e.g., off, sleep, or dormant) for a configured subset of cells (e.g., capacity boosting cells) depending the time in the day. For example, the WTRU may determine that a capacity boosting cell has an availability state as on in certain hours of the day, deep sleep in other configured hours, and off in a third set of configured hours of the day or night.

[0117] The WTRU may implicitly assume a certain availability state from based on the availability state of an associated cell (e.g., another carrier of the same MAC entity, another carrier in the same cell group, another carrier in the same gNB, another sector in the same gNB, or a configured associated cell or capacity boosting cell).

[0118] The WTRU may implicitly assume a certain availability state from a detection of a PSS (e.g., only) signal or a simplified / stripped down SSB signal. The WTRU may implicitly assume a certain availability state from a detection of an RS signal (e.g., CSI-RS, PRS, TRS) or the lack thereof. The WTRU may implicitly assume a certain availability state from a UE’s RRC state (idle, inactive, or connected mode). The WTRU may implicitly assume a certain availability state from whether paging has been received, within a configured time window. The WTRU may implicitly assume a certain availability state from whether system information (e.g., periodic SI or a subset of SIBs) have been received, within a configured time window.

[0119] The WTRU may implicitly assume a certain availability state from a measured channel condition(s) being below -or above- a threshold. The WTRU may assume a change of NES state based on a change of measured channel conditions or making a channel measurement below -or above- a threshold. For example, the WTRU may use degradation in measurements of SSBs or CSI-RS, in combination with other signaling- to determine the NES state. For example, a configured window following the DCI reception can be used to measure SSBs and / or CSI-RS for degradation, and if a delta of SSB-RSRP drop is measured the WTRU may determine that the NES state has changed and assume associated actions for such NES state (e.g., trigger for CHO candidate selection or for group scheduling for a mobility command).

[0120] The WTRU may be configured to monitor an indication that may characterize the level of network activity (e.g., an availability state). The network activity may be associated with a gNB and / or a cell. The WTRU may assume the same availability state for (e.g., all) cells part of the same gNB, e.g., cells of the same MAC entity. The network activity indication (e.g., the presence indication) may include of a channel (e.g., a PDCCH) and / or a signal (e.g., a sequence). The activity indication or the NES state change indication / command may indicate the level of activity the WTRU may expect from the associated gNB and / or cell, e.g., reduced activity. The activity indication may include activity information of other gNBs / cells. The activity indication may be a PDCCH including group common signaling. For example, the NW may transmit a group common DCI to a group of WTRUs (e.g., WTRUs in the serving cell) indicating a change of an activity state or activity level in UL and / or DL. The CRC of the PDCCH may be scrambled with a dedicated “activity indication RNTI or an NES-RNTI” A WTRU may be configured with at least one search space associated with the monitoring occasions of the activity indication PDCCH. The indication may include of a go-to-sleep signal, e.g., a predefined sequence. When WTRU detects the sequence, the WTRU may expect a reduced activity level over a specific time duration. The WTRU may activate C-DRXfor the period of time indicated. Two sequences may be used to indicate regular activity and reduced activity.

[0121] The signaling within the PDCCH or the activity indication may include at least one of the following: the signaling within the PDCCH or the activity indication may include an expected activity level of the associated gNBs / cells over a specific time interval (e.g., an availability state). The activity levels may be predetermined and / or configured and may, for example, include of regular and reduced activity. The signaling may indicate the activity level. For example, bit “1” may indicate regular activity, and bit "0" may indicate reduced activity.

[0122] For an activity level (e.g., availability state), transmission and reception attributes may be defined. For example, during reduced activity, the WTRU may not be expected to monitor certain PDCCH search spaces (including all SSs), and / or receive a certain type of PDSCH (including all PDSCH), and / or transmit PUCCH / PUSCH, and / or perform certain measurements. The WTRU may start or stop monitoring PDCCH and / or TCI states associated with determined NES state, including PDCCH resources or TCI states associated with (de)activated TRPs or spatial elements.

[0123] A set of configurations may be associated with an activity level and may be used / applied when that activity level is indicated (e.g., an NES parameter set). For example, SS configurations, CSI reporting configurations, indices of transmitted SSBs, etc. A set of configurations may have an attribute associated with an activity level (e.g., a tag that may be set to “reduced activity”).

[0124] The time interval over which an activity level is assumed may be signaled in the PDCCH or part of the activity indication. The time interval may be indicated using a bitmap where a bit in the bitmap may be associated with a specific duration, e.g., a slot or a frame. For example, bit “1” may indicate regular activity and bit “0” may indicate reduced activity on an associated frame.

[0125] The time interval may be indicated with a start time and length of interval. The start time may be defined. For example, it may be determined by adding a fixed offset to the time the indication is received. The length of the interval may be configured or signaled in the indication PDCCH.

[0126] The time interval over which an activity level is assumed may be predetermined. The WTRU may assume an interruption delay (or more generally a time till the NES state changes) after the NES state change command reception (e.g., after the last symbol or slot on which the command was received). The interruption time may be in absolute time, a number of symbols, and / or a number of slots.

[0127] The WTRU may determine that an uplink or downlink resource or signal is available for transmission / reception and / or measurements for the determined network availability state if it is applicable in the active availability state. The WTRU may determine that a subset of measurement resources and / or signals (e.g., SSBs, CSI-RS, TRS, PRS) are not applicable in certain availability states. The WTRU maydetermine that a subset of uplink or downlink resources (e.g., PRACH, PUSCH, PUCCH) are not applicable in certain availability states. The WTRU may transmit some uplink signals (e.g., only) in a subset of NW availability states (e.g., SRS, pSRS, PRACH, UCI).

[0128] The terms network NES state and cell NES state may be used interchangeably. A WTRU may know the cell NES state for one or more cells, e.g., through network configuration and indication. When used as network NES state, the NES states of one or more cells may be serving cells, neighbor cells etc.

[0129] Synchronization Signals and Procedures may be associated with NR. Downlink Synchronization may be associated with a process in which a WTRU detects the radio frame boundary (e.g., the exact timing when a radio frame starts) and orthogonal frequency-division multiplexing (OFDM) symbol boundary (e.g., the exact timing when an OFDM symbol starts). The process may be done by detecting and analyzing synchronization signal Block (SSB).

[0130] The Synchronization Signal and PBCH block (SSB) may include primary and secondary synchronization signals (PSS, secondary synchronization signal (SSS)), wherein the PSSs and SSSs may occupy 1 symbol and 127 subcarriers, and PBCH spanning across 3 OFDM symbols and 240 subcarriers, and on one symbol leaving an unused part in the middle for SSS as show in FIG. 2. The (e.g., possible) time locations of SSBs within a half-frame may be determined by sub-carrier spacing and the periodicity of the half-frames where SSBs are transmitted is configured by the network. During a half-frame, different SSBs may be transmitted in different spatial directions (e.g., using different beams, spanning the coverage area of a cell).

[0131] Within the frequency span of a carrier, multiple SSBs may be transmitted. The PCIs of SSBs transmitted in different frequency locations may not have to be unique, e.g., different SSBs in the frequency domain may have different PCIs. When an SSB is associated with an remaining system information (RMSI), the SSB may be referred to as a Cell-Defining SSB (CD-SSB). An SpCell may be associated to a CD-SSB located on the synchronization raster.

[0132] FIG. 2 illustrates a time-frequency structure of SSB. Polar coding may be used for PBCH. The WTRU may assume a band-specific sub-carrier spacing for the SSB unless a network has configured the WTRU to assume a different sub-carrier spacing. PBCH symbols may carry their own frequency multiplexed DMRS. QPSK modulation may be used for PBCH.

[0133] Cell search may be a procedure by which a WTRU acquires time and frequency synchronization with a cell and detects the Cell ID of that cell. NR cell search may be based on the primary and secondary synchronization signals, and PBCH DMRS, located on the synchronization raster.

[0134] System Information (SI) may be divided into the master information block (MIB) and a number of system information blocks (SIBs). The MIB may be transmitted on the BCH with a periodicity of 80 ms andrepetitions made within 80 ms (TS38.212) and may include parameters that are needed to acquire SIB1 from the cell.The SIB1 may be transmitted on the DL-SCH with a periodicity of 160 ms and variable transmission repetition periodicity within 160 ms. The default transmission repetition periodicity of SIB1 may be 20 ms, and the actual transmission repetition periodicity may be up to network implementation.

[0135] MIB and SIB1 may make up the minimum system information (MSI) required to operate on a cell. For SSB and CORESET multiplexing pattern 1, an SIB1 repetition transmission period may be 20 ms. For SSB and CORESET multiplexing pattern 2 / 3, SIB1 transmission repetition period may be the same as the SSB period (TS 38.213). SIB1 may include information regarding the availability and scheduling (e.g., mapping of SIBs to SI message, periodicity, Sl-window size) of other SIBs with an indication of whether one or more SIBs are (e.g., only) provided on demand, and, for example, the configuration needed by the WTRU to perform the SI request. SIB1 may be cell-specific SIB.

[0136] SIB1 may be received. The Master Information Block (MIB) on PBCH may provide the WTRU with parameters (e.g., CORESET#0 configuration) for monitoring of PDCCH for scheduling PDSCH that carries the System Information Block 1 (SIB1). PBCH may indicate that there is no associated SIB1. The WTRU may be pointed to another frequency from where to search for an SSB that is associated with a SIB1 as well as a frequency range where the WTRU may assume no SSB associated with SIB1 is present. The indicated frequency range may be (e.g., confined) within a contiguous spectrum allocation of the same operator in which SSB is detected.

[0137] Features described herein may be associated with SSB indexing and SSB burst. An SSB within an SSB burst set (e.g., all of the SSBs within the 5 ms period of the SSB transmission) may be assigned with a unique number starting from 0 and increasing by 1 . The number may reset to 0 in the next SSB burst set (e.g., next 5 ms span after SSB transmission cycle (e.g., after the default cycle of 20 ms). The unique number (e.g., SSB Index) may be informed to the WTRU via PBCH DMRS and via PBCH payload. The candidate SSBs in a half frame may be indexed in an ascending order in time from 0 to L-1. A WTRU may determine the 2 LSB bits, for L = 4, or the 3 LSB bits, for L > 4 , of a SSB index per half frame from a one- to-one mapping with an index of the DMRS sequence transmitted in the PBCH. For L = 64 , the WTRU may determine the 3 MSB bits of the SS / PBCH block index per half frame by PBCH payload bits.

[0138] FIG. 3 illustrates an SSB burst with a periodicity of 20 ms. FIG. 3 illustrates an SSB beam sweeping within SSB burst sets.

[0139] Beam failure may be detected and recovered. Beam failure detection and recovery procedures may be implemented to enable reliable and uninterrupted communication between the WTRU and the base station. In examples associated with beam failure detection may include the monitoring of beam-specific reference signals. The WTRU may continuously receive the signals from the base station, allowing it totrack the beamforming performance. If the quality of the received signals deteriorates below a certain threshold, indicating a potential beam failure, the WTRU may trigger a beam failure event. Once a beam failure event is detected, the WTRU may initiate the beam failure recovery procedure. The WTRU may first try to restore the connection with the base station by using the last known beamforming configuration. If the attempt fails, the WTRU may search for alternative beams and performs beam sweeping, where it may scan different beamforming configurations in search of a stronger and more reliable beam.

[0140] In a beamformed NR system, the WTRU may be configured to maintain one or multiple beam pairs. The WTRU may monitor certain periodic CSI-RS on a serving DL beam to assess its quality and may compute a corresponding quality metric. If the beam’s quality in a given RS period is below a configured threshold, the WTRU’s physical layer (PHY) entity may report a beam failure instance (BFI) to the MAC sub-layer.

[0141] In order to re-establish lost beam pair(s) in a faster manner compared to the RLM / radio link failure (RLF) procedure, the WTRU’s MAC layer may employ a BFR procedure in which a beam failure recovery request is reported to the network upon detecting a beam failure. BFR may be configured for beam maintenance on the SpCell and / or SCell.

[0142] The MAC entity may maintain a beam failure instance counter (BFLcounter) for the purpose of beam failure detection. The MAC entity may count the number of beam failure instance indications received from the PHY entity. If the BFI counter exceeds a certain maximum number of BFIs, a BFR request may be triggered to notify the serving gNB that a beam failure has been detected.

[0143] The MAC entity may reset the BFI counter (e.g., only) after a beam failure detection timer (BFD_timer) has expired. This may help provide hysteresis in the detection function. In examples, the WTRU may reset the BFD timer if a BFI is indicated by the PHY layer. For example, the MAC entity may (e.g., only) reset the BFI counter after observing no BFI indications from PHY for three consecutive CSI-RS periods if the BFD timer is configured to 3 CSI-RS periods.

[0144] To report a BFR request regarding a beam failure on an SpCell, the WTRU may initiate a random access procedure with certain parameter values (e.g., PreambleTransMax, power ramping step, and the target received preamble power). Such random access procedure may be used for beam re-establishment, as the WTRU may select an appropriate PRACH preamble and / or PRACH resource dependent on the best measured downlink beam (or DL SSB). The WTRU may have means to reestablish a beam pair when it can determine an association between DL beams and UL preambles and / or PRACH occasions, whereby the downlink beam selected by the WTRU is tested by receiving the random access response (RAR) on it. Such reestablishment random access (RA) procedure may be made faster if the gNB configures a certain set of contention-free PRACH preambles / resources, which may be prioritized for selection by the WTRUupon initiating the RA procedure. Upon completion of the Random Access procedure, beam failure recovery for the SpCell may be considered complete.

[0145] The beam failure and detection procedure may address secondary cells. Once beam failure is detected on a Secondary Cell (SCell), the WTRU may trigger beam failure recovery by transmitting a BFR MAC CE specifically for that SCell. The WTRU may select a suitable beam for the affected SCell if there is an alternative available and includes the information, along with details about the beam failure, in the BFR MAC CE. Upon reception of a PDCCH indicating an uplink grant for a new transmission for the HARQ process used for the transmission of the BFR MAC CE, beam failure recovery for the SCell may be considered complete.

[0146] RRC may configure the following parameters in the beamFailureRecoveryConfig, beamFailureRecoverySpCellConfig, beamFailureRecoverySCellConfig and the radioLinkMonitoringConfig for the Beam Failure Detection and Recovery procedure: beamFailurelnstanceMaxCount for the beam failure detection (per Serving Cell or per BFD-RS set of Serving Cell configured with two BFD-RS sets); beamFailureDetectionTimer for the beam failure detection (per Serving Cell or per BFD-RS set of Serving Cell configured with two BFD-RS sets); beamFailureRecoveryTimer for the beam failure recovery procedure for SpCell; rsrp-ThresholdSSB: an RSRP threshold for the SpCell beam failure recovery; rsrp- ThresholdBFR: an RSRP threshold for the SCell beam failure recovery or for the beam failure recovery of BFD-RS set of Serving Cell; powerRampingStep: powerRampingStep for the SpCell beam failure recovery; powerRampingStepHighPriority: powerRampingStepHighPriority for the SpCell beam failure recovery; preambleReceivedTargetPower: preambleReceivedTargetPower for the SpCell beam failure recovery; preambleTransMax: preambleTransMax for the SpCell beam failure recovery; scalingFactorBI: scalingFactorBI for the SpCell beam failure recovery; ssb-perRACH-Occasion: ssb-perRACH-Occasion for the SpCell beam failure recovery using contention-free Random Access Resources; ra-ResponseWindow: the time window to monitor response(s) for the SpCell beam failure recovery using contention-free Random Access Resources; prach-Configurationlndex: prach-Configurationlndex for the SpCell beam failure recovery using contention-free Random Access Resources; ra-ssb-OccasionMasklndex: ra-ssb- OccasionMasklndex for the SpCell beam failure recovery using contention-free Random Access Resources; ra-OccasionList: ra-OccasionList for the SpCell beam failure recovery using contention-free Random Access Resources; candidateBeamRSList: list of candidate beams for SpCell beam failure recovery; candidateBeamRS-List-r16: list of candidate beams for SCell beam failure recovery or list of candidate beams for beam failure recovery of a Serving Cell for BFD-RS set one; candidateBeamRS-List2- r17: list of candidate beams for beam failure recovery of a Serving Cell for BFD-RS set two.

[0147] The following WTRU variables may be used for the beam failure detection procedure. BFLCOUNTER (per Serving Cell or per BFD-RS set of Serving Cell configured with two BFD-RS sets): counter for beam failure instance indication which is initially set to 0.

[0148] Operators may be making use of energy saving techniques in deployments to bring the costs down to operate networks. The cells may be applying energy saving techniques in different domains, e.g., time, power, spatial, frequency.

[0149] FIG. 4 illustrates a failure resource and recovery beams. The WTRUs may monitor failure detection resources and associated reference symbols to detect beam failure. Upon detecting beam failure, the WTRUs may measure for configured recovery beams and associated reference signals to indicate potential beams through which they may be recovered out of beam failure. One such example scenario is shown in FIG. 4.

[0150] When the cells are applying energy saving techniques to failure detection resources, recovery beams or both, the beam failure detection and recovery procedures may not function. The WTRU may be able to perform beam failure detection and beam failure recovery procedures while operating in networks where the failure detection resources are. Recovery beams may be applying energy saving techniques.

[0151] Examples described herein may be associated with the following. NES techniques on failure detection resources may lead the WTRU to detect Beam Failure while the WTRU has suitable coverage. NES techniques on Recovery Beams may hinder / delay the WTRU finding / measuring the suitable recovery beam. The WTRU may report beam failure (e.g., only) after having made recovery beams measurements. If recovery beams are undergoing NES, the WTRU may not be able to support the recovery procedure.

[0152] Features described herein may be associated with a carrier aggregation (CA) pre-beam failure indication, e.g., with on-demand recovery resources. In examples, a WTRU may provide a pre-BF indication to the NW (e.g., the WTRU may provide a pre-BF indication before BF detection). In response, the NW may trigger a sweep (e.g., an on-demand sweep) of recovery beams (e.g., recovery beam reference signals (RSs)) for which the gNB provides the time / freq / RS details. The WTRU may measure the recovery beams from the sweep and indicate a suitable beam (e.g., a beam that satisfies a condition) to the network for recovery.

[0153] Failure detection resources (FDR) may be configured. The NW may have turned off the neighboring recovery beams to save energy (e.g., no WTRUs in neighboring beams). The WTRU may be connected to a first cell (e.g., such as an SpCell) and to a second cell (e.g., an SCell). The WTRU may be configured with the following for the 2nd cell. The WTRU may be configured with a set of failure detection resources (FDR) for beam failure detection. The WTRU may be configured with a set of recovery beams for beam failure recovery. The recovery beams may be undergoing NES (e.g., time / spatial / power domain).The WTRU may be configured with a set of SR resources and / or UL wake up signal (WUS) resources (e.g., an uplink indication configuration) to provide a pre-beam failure indication.

[0154] The WTRU may report (e.g., transmit to a network node / gNB) a pre-BF indication if BFD_counter on the 2nd cell (e.g., a beam failure detection counter value) > Threshold 1 (e.g., a first threshold) (where Thresholdl < BFI_MAX_Count) (e.g., BFI_MAX_Count may be a second threshold). The WTRU may receive an indication (e.g., the indication may be associated with network transmission) from the gNB over the 1st cell providing any of the following information (e.g., information associated with network transmissions). The information may include a candidate beam recovery RS (e.g., synchronization signal block (SSB)) from a pre-configured list which will be sweeped (same or different cell) (e.g., the information may include a sweep of on-demand SSB transmissions). The information may include T_sweep_duration, a time duration within which a recovery RS of the 2nd cell will be transmitted. The information may include T_burst_start (start of the burst in time), periodicity, and / or F_burst_start (start of the burst in Freq / PRB) for the BF avoidance SSB Burst. A different bandwidth part (BWP) ID may be indicated by the network. The information may include recovery beams and FDRs. The information may include a flag indicating that the WTRU is to transmit an indication if recovery beams are no longer needed. The WTRU may monitor and / or measure the recovery beams (e.g., the RSs associated with the network transmissions) in the sweep according to the gNB indication. The WTRU may select a suitable recovery beam based on the measurement(s) of the RS(s), for example., the WTRU may select a recovery beam that satisfies a threshold (e.g., a fourth threshold), where, in examples, the recovery beam satisfying the threshold may be determined by the recovery beam being better than the threshold (e.g., based on the measurement(s)).to the WTRU may report the suitable beam and / or measurement(s) to the NW. The WTRU may transmit an indication (e.g., to the network) on the 1st cell (e.g., using a resource from the 1st cell) comprising of the following (e.g., the WTRU may transmit the indication based on the measurement of the RSs). If (BFD_counter >= BFI _MAX_Count), an indication, via a BFD MAC CE, with the suitable recovery beam (e.g., selected recovery beam) on a 2nd cell may be transmitted to the network. If (BFD_counter resets and 2nd Cell RSRP > Thresholds) (e.g., if the FDR resources satisfy a third threshold), an indication that indicates that recovery beams (and / or on-demand sweeps) are no longer needed (e.g., for the 2nd cell) may be transmitted to the network (e.g., using the 1st cell).

[0155] Beam failure may be avoided by SSB burst adaptation. In examples, upon network (NW) adaptation of an SSB burst, and upon determining that a WTRU is at risk of beam failure, the WTRU may provide a pre-beam failure (pre-BF) indication to the network node / gNB requesting a set of SSB transmissions. In response, the network node / gNB may switch to a full SSB transmission (e.g., narrow beam SSBs / FDRs).

[0156] In examples, the WTRU may be configured to use network energy saving (NES) beams (e.g., wider beams with potentially low power) as FDRs. Upon determining that a beam failure detection counter value (e.g., BFD_counter) reaches a first threshold (e.g., Threshold 1 ), the WTRU may request non-NES FDR. The WTRU may be connected to a first cell (e.g., a serving cell, such as an SpCell). The WTRU may be configured with the following.

[0157] The WTRU may be configured with a first set of full SSBs for FDR and a second (NES) set of FDR (e.g., a reduced number of SSBs or lower spatial / power beams) for beam failure detection (BFD), as well as an indication of an active set. In addition, the WTRU may be configured with a set of recovery beams for beam failure recovery. The WTRU may also be configured with an uplink (UL) indication configuration (e.g., SR / MAC-CE / UL WUS) to request switching to the first (normal) FDR set or an on- demand SSB transmission.

[0158] If the BFD_counter on the SpCell (e.g., the beam failure detection counter value for the first cell) exceeds the first threshold (Thresholdl) and remains less than a second threshold (e.g., BFI_MAX_Count), and if the second set of FDR is currently active, the WTRU may transmit an uplink indication (e.g., SR, MAC-CE, or UL WUS) on the serving primary cell (SpCCell) to request activation of the first set of failure detection resources.

[0159] The WTRU may receive, from the network node / gNB, an indication (e.g., via MAC signaling or DCI) of the activation of the first set of failure detection resources or on-demand (full) SSB (which may apply to one or more cells, such as a first cell or a second cell).

[0160] If on-demand SSB or the first set of FDR are received and at least one measured beam is determined to be above a threshold (e.g., a fourth threshold), the WTRU may provide an indication of the preferred beam and / or may request activation of the first (normal) set of FDR (e.g., via an indication to the network node / gNB).

[0161] The WTRU may start monitoring the first FDR set upon receiving the network indication. If the beam failure detection counter value (BFLCOUNTER) for the SpCell is greater than or equal to the second threshold (e.g., BFI _MAX_Count), the WTRU may transmit a Random Access (RACH) procedure carrying a beam failure recovery MAC control element (MAC CE) on the SpCCell. This transmission may include measurements obtained from the recovery beams that the WTRU used to determine a suitable beam for recovery.

[0162] Beam failure may be detected across multiple related cells (e.g., anchor and non-anchor).The gNB may configure a WTRU with beam failure detection resources for cell 1 using the RSs from cell 1 and cell 2 (cell 2 may or may not be a serving cell). The WTRU may perform weighted increment of beam failure counter over cell 1 BFIs and cell2 BFIs to determine BFD for cell 1 . In examples, the NW mayconfigure the WTRU to use the FDRs from two cells (e.g., co-located cells) to perform BFD on one cell. A WTRU may at least be connected to a 1st cell, celH , applying one of the NES techniques.

[0163] The WTRU may be configured with the following for the beam failure detection over the 1st cell. The WTRU may be configured with a 1 st set of failure detection resources (FDR) over the RSs from the 1 st cell. The WTRU may be configured with a 2nd set of failure detection resources (FDR) over the RSs from a 2nd cell, Cell2, where Cell2 may be a serving cell or a non-serving cell for the WTRU. The WTRU may be configured with a set of recovery beams for beam failure recovery purpose for the 1st cell. The WTRU may make the measurements of 1st set of FDR and 2nd set of FDR. The PHY layer at the WTRU may generate BFI for cell 1 if the FDR in the 1st set are (e.g., are measured to be) less than a threshold RSRP1 , and BFI for cell 2, if (e.g., all) the FDR in 2nd set are (e.g., are measured to be) less than a threshold RSRP2.

[0164] The WTRU may determine BFD based upon BFD_counter exceeding the BFD_MaxCount where the BFD_counter counts failures from BFI of both cells received from PHY and weights the counts.

[0165] BFLcounter (n+1) = BFLcounter (n) + 1 / x (if BFI on celH) + 1 (if BFI on cell 2) where x= configured by RRC.

[0166] Upon determination of BFD on celH, the WTRU may perform the BF recovery procedure by (a) transmitting a RACH if CelH is an SpCell, (b) by transmitting beam failure recovery MAC CE on the SpCell if CelH is a non-SpCell.

[0167] A beam failure configuration may be associated with switching for NES. FIG. 5 illustrates a WTRU anticipated BF indication upon missing an SSB adaptation (NES) indication.

[0168] In examples, the network may be adapting FDRs based upon NES indication. The WTRU may continue monitoring the non-NES FDR. The WTRU may provide a pre-BF indication to the NW based upon the measurements made on non-NES FDR and if RSRP(FDR_set1_Excluded_FDR_set2) < RSRP(FDR_set2). In response, the NW may provide an indication of an actual NES state of one or more cells. The WTRU may start monitoring NES FDR set for Beam failure procedure.

[0169] An NES based indication may provide the WTRU suitable FDR / recovery-RS periodicity / config. The network may be transmit an NES based indication through signaling mechanisms, e.g., WTRU dedicated, group common, or broadcast signaling. The WTRU may miss the NES indication leading the WTRU to be a-sync with the NW NES state (e.g., the WTRU may or may not know the latest NES state of the cell), and the WTRU may apply different NES state assumptions based upon its known (e.g., previous) NES state.

[0170] The WTRU may be configured with the following: the WTRU may be configured with a 1 st / 2nd set of failure detection resources and BF detection timers / counters for beam failure detection in normal / NES mode. The WTRU may be configured with a set of recovery beams for beam failure recoverywhere the recovery beams may be applying NES in time domain (time / spatial / power domain). The WTRU may be configured with An UL SR configuration requesting appropriate BFD / BFR configuration and on- demand RS. The WTRU may measure RSRP over the normal FDR and over the NES FDR.

[0171] If any of the following conditions is met: (i) RSRP (Set1_Excl_Set2) < RSRP (Set 2) + Th4, (ii) BFD_counter > Thresholdl (where Threshold 1 < BFI_MAX_Count), the WTRU may transmits the configured SR [MAC-CE or UL WUS] on the SpCell requesting on-demand sweep of “failure detection resource RS” and recovery beam RSs (e.g., including (e.g., all) the SSBs of the SpCell or CSI-RS). The WTRU may provide an indication of currently active BF configuration or the assumed NES state.

[0172] The WTRU may switch to a second BF configuration [BFD_Timers, BFI_Max_Count] and a second set of failure detection resources upon receiving a (missed) NES indication from the gNB. A (missed) NES indication may indicate one or more of the following: a sweep timing / details for the transmission of FDR and recovery beams, e.g., on-demand SSBs; or the active NES state, e.g., active RS / SSB periodicity

[0173] The WTRU may start to monitor the activated RS / SSB according to the active set associated to the active NES / normal mode. The WTRU may transmit beam failure recovery MAC CE comprising the measurements made on the recovery beams if BFD_counter >= BFI_MAX_Count, through RACH if BF is detected on the Spcell, or through the Spcell if BF is detected on an Scell.Features described herein may be associated with terminology for network energy saving.

[0174] A Cell DTX active period may include a duration of time over which a configured cell DTX pattern is active (e.g., periods of time during an On Duration periods of a Cell DTX pattern). The WTRU may be predefined and to monitor PDCCH and other DL signals and channels during such time. This may be applicable (e.g., only) after a cell DTX configuration has been indicated by the NW to be activated.

[0175] A Cell DTX inactive period may include a duration of time over which a configured cell DTX pattern is not active / inactive (e.g., periods of time outside periodic On Duration periods of a Cell DTX pattern). This may be applicable (e.g., only) after a cell DTX configuration has been indicated by the NW to be activated.

[0176] A Cell DRX active period may include a duration of time over which a configured cell DRX pattern is active (e.g., periods of time during an On Duration period of a Cell DRX pattern). The WTRU may be predefined to be allowed to transmit UL signals and on UL channels during such time. This may be applicable (e.g., only) after a cell DRX configuration has been indicated by the NW to be activated.

[0177] The Cell DRX inactive period may include duration of time over which a configured cell DRX pattern is not active / inactive (e.g., periods of time outside periodic On Duration periods of a Cell DRX pattern). This may be applicable (e.g., only) after a cell DRX configuration has been indicated by the NW to be activated.

[0178] The Activated Cell DRX / DTX may include A state of a configured cell DRX or Cell DTX pattern, where such state has been activated by L1 / L2 DL signaling, RRC (re)-configuration, and / or cell common configurations, and has not been de-activated.

[0179] The De-activated Cell DRX / DTX may include a state of a configured cell DRX or Cell DTX pattern, where such state has been deactivated by L1 / L2 DL signaling, RRC (re)-configuration, and / or cell common configurations.

[0180] Features described herein may be associated with a link between availability state, NES state, and Cell DTX / DRX. The WTRU may determine a cell DTX state implicitly from a determined active availability state, and visa-versa. The WTRU may determine a cell RTX state implicitly from a determined active availability state, and visa-versa.

[0181] The terms alternative cell and stable cell may be used interchangeably as described herein. The WTRU may be configured with a list of stable cells (e.g., alternative cells that will not turn off, e.g., some macro cells). The list may be either a list of alternative cells per serving / camped cell or a general list of PCIs for the whole NW, Tracking area, etc. The WTRU may be configured with measurement object configuration for the alternative cells. The WTRU may be configured or predefined with stable cells to perform initial access, mobility, or cell reselection on in the event the current serving cell (e.g., an NES cell) is turned off or activates NES state. The WTRU may be configured per broadcast or dedicated signaling with a list of stable cells, possible per serving cell, per gNB, per PLMN, or per network identity. Stable cells may correspond to cells that will not apply NES techniques (e.g., non-NES cells) and / or not configured with any NES technique.

[0182] An NES cell may include a cell configured with at least one NES technique or method (e.g., cell DRX / DTX, spatial domain adaptation, power domain adaptation, cell turn off, sleep etc.). An NES cell may be designated as such (e.g., only) if it has activated the NES technique. The terms non-NES cell and stable cell may be used interchangeably. The terms NES cell and non-stable cell may be used interchangeably.

[0183] An Ref-SpCell or Anchor cell may include a reference primary cell from which the WTRU may rely on for initial access, RLM, BFD, and / or paging procedures. A Ref-SpCell may be associated with one or more other SpCells or SCells, which may be NES cells. System information broadcasted from the Ref- SpCell may advertise / indicate the existence of other associated cells with it, including configurations associated with NES (e.g., pre-synch signal - as described herein, transmission occasions, PRACH configurations, and NES state cycle length and information / configuration). The terms Ref-SpCell and anchor cell may be used interchangeably.

[0184] The terms non-NES state, deactivated NES, and NES inactive state may be used interchangeably to refer to cases where a cell is operating normally without NES mechanisms (e.g., fullpower, no cell DTX, etc.). The terms NES state of the network and NES state of the cell may be used interchangeably. NES state of the network may include the NES state of one or more cells.Beam failure detection and beam failure recovery may include the following terminology.

[0185] For transmission using low power Tx and power amplifier, the gNB may be equipped with a low power transmitter and / or power amplifier (PA). The reference signals associated with beam failure detection, beam recovery, synchronization sequences, including SSB or reference signals described herein, may be transmitted by the gNB using the lower power Tx and / or PA.

[0186] The gNB transmission of reference signals using low power Tx and PA may be associated to the cell NES state. In examples, the reference signals may be transmitted using low power Tx and PA when the associated cell is in non-NES state. The sync signals may be transmitted using normal Tx and PA when the associated cell is in NES .

[0187] BFD_Counter and BFLCounter may be used interchangeably, which are counters used at the WTRU to count the beam failure instances for a given cell or for a given FDR set at the MAC layer.

[0188] Features described herein may be associated with a single connectivity (e.g., a WTRU configured with a single cell group, that has a PCell, and optionally one or more SCells). This is for the sake of brevity, and examples described herein may be applicable to the case of dual connectivity where the WTRU is (e.g., also) configured with a secondary cell group (e.g., including a PSCell and optionally, one or more SCells). For example, the related cells described herein may belong to different cell groups.

[0189] In examples involving RRC, the BFD and BFR related configurations may be indicated to the WTRU according to the following structure. For a serving cell (e.g., SCell or SpCell), the WTRU may be configured with a servingCellConfig IE (spCellConfigDedicated for the SpCell and sCellConfigDedicated for an SCell). servingcellConfig may include the configuration of one or more DL bandwidth part (BWP) (configured in the BWP-Downlink IE) and one or more UL bandwidth part (BWP) (configured in the uplinkConfig IE that includes one or more BWP-UplinkDedicated IE).

[0190] BWP-Downlink may include a BWP-DownlinkDedicated IE. BWP-DownlinkDedicated IE may include radioLinkMonitoringConfig IE and BeamFailureRecoveryRSConfig. The radioLinkMonitoringConfig IE may include failure detection related configuration, such as beam failure detection resources, the beam failure max count value, and beam failure detection timer. BeamFailureRecoveryRSConfig may include candidate beams for beam failure recovery in case of beam failure detection.BWP-UplinkDedicated may include the beamFailureRecoveryConfig IE. beamFailureRecoveryConfig may include the configuration of the RACH resources and candidate beams for beam failure in case of beam failure detection (e.g., rach-ConfigBFR, BFRTimer, PRACH resources for the candidate beam list, etc.)

[0191] The lEs described herein may be reused / extended to enable examples described herein. IES not described herein may be included. In examples, the WTRU may be provided with multiple IEs for a corresponding NES state. For example, the WTRU may be configured with a list of beamFailureRecoveryConfig IEs, corresponding to the different NES state, a list of beamFailureRecoveryRSConfig IEs, corresponding to the different NES state, etc. In examples, a common part may exist for (e.g., all) NES states and a part that is (e.g., only) associated with an NES state (e.g., the WTRU may have a beamFailureRecoveryConfig that is applicable to a non-NES state, and the WTRU may use (e.g., all) the configurations in that IE (except for the BFRTimer) for all the NES states. The WTRU may be provided with individual BFRTimer values for (e.g., different) NES states. The BFRTimer values for the different NES states may be absolute values or relative values compared to the BFRTimer for the non-NES state (e.g., a scaling factor).

[0192] Examples described herein that are associated with beam failure detection and recovery may be described with respect to a (e.g., a special) cell, e.g., PCell or PSCell, Examples described herein may be described for non-special cells. Such examples are for the sake of clarity of exposition, and the examples proposed may be valid both special and non-specials cells. Examples described herein may be applied to the beam failure detection and recovery procedures for (e.g., all) serving cells.

[0193] An anticipated beam failure indication may be associated with on-demand resources. A WTRU may monitor a beam. For a WTRU connected to a serving cell, the WTRU may be configured to monitor one or more reference signals with a given periodicity to detect beam failure on that serving cell. The serving cell may be the primary cell SpCell of the cell group. The reference signals may be SSBs, CSI-RS, or a (e.g., suitable) reference signal(s).

[0194] In examples, a WTRU may be configured with the beam monitoring RSs explicitly. In examples, the WTRU may select the suitable RSs to perform beam monitoring and beam failure detection by itself through the rules pre-configured to the WTRU. In examples, the WTRU may select the RSs which have the QCL relation with the CORESET where WTRU is monitoring its PDCCH for that cell. The QCL relation may be one or more of a Type A, Type B, Type C, Type D, or a different relation.

[0195] In examples, a WTRU may be configured with two sets of beam monitoring or failure detection resources. The network may use one set of resources for normal mode operation when the network is not modifying the signals for energy saving purpose. A (e.g., another) set of resources may be transmitted by the network when the network is applying NES technique (time, frequency, power or spatial, etc.). In examples, there may be more than two sets of resources when the network may employ different NES techniques. The network configuration may provide the WTRU about the information of which resources correspond to which NES technique.

[0196] In examples, a WTRU may be configured with two (or more) sets of beam monitoring or FDR sets for normal BFD / R operation for cell x, which could be the case for example when the WTRU is connected to two (or more) TRPs for cell x. In examples, the WTRU may be provided additional FDR sets corresponding to the NES states for a TRP. For example, the WTRU may be configured with two (e.g., normal) FDR sets for normal operation and 2 NES FDR sets for NES operation for the case of two TRPs. For the case of N1 TRPs having N2 NES states (e.g., each), the WTRU may be configured with N1xN2 FDR sets.

[0197] A WTRU may update the beam monitoring periodicity. A WTRU may change the periodicity with which it is performing beam failure detection for its serving cell. The change in the periodicity may be related to the network applying one of the energy saving techniques. The network may apply energy saving techniques in time, frequency, spatial or power domains, for example. The WTRU may be configured by the network the pattern and the change in one of RSs features such as periodicity, frequency, bandwidth, power, spatial pattern due to network decision, e.g., to save energy. In examples, the WTRU may be indicated by the network about the change in one of the physical properties or features in the RSs that it is using to detect beam failure. The network may provide the indication to the WTRU through dynamic signaling. In examples, this could be through a DCI. The WTRU may receive The DCI through dedicated, group common or broadcast signaling. The WTRU may receive the indication in a MAC CE. The WTRU may receive the indication in an RRC signaling (e.g., dedicated RRC message, SIB signaling, etc.,). In examples, the WTRU may derive the physical property of RS and the other parameters, e.g., start instant etc., by itself through the network provided configuration.

[0198] In examples, the WTRU may first receive a set of possible physical properties / features of the RSs that it can use for beam failure detection (e.g., each associated with an index, identity, etc.,), and the indication sent from the network is the index / identity that is to be used by the WTRU for BFD. In examples, one of the sets of possible physical properties / features of the RSs may be configured to be the default configuration (e.g., WTRU will assume the RSs to have the configuration / properties associated with The configuration index / identity).

[0199] In examples, a WTRU may receive the indication about the change in one of the physical properties of the RS through the cell for which the WTRU is performing the beam failure detection. In examples, a cell, cell 1 , may provide the indication of the change in RS for a different cell, cell 2. In examples, cell 2 may belong to a cell group, and cell 1 may be the primary cell of that cell group. In example, cell 1 and cell 2 may belong to different cell groups (e.g., WTRU configured with dual connectivity, and cell 1 belongs to the master cell group, while cell 2 belongs to the secondary cell group, or vice versa).

[0200] In examples, a WTRU may receive an indication from the network that a cell or group of cells are changing their NES state. The indication may be received in a WTRU dedicated signaling or through a common signaling. The common signaling may be group common or broadcast signaling. The WTRU may further be configured with beam failure monitoring / detection resources for a cell or group of cells that are associated with an NES state. If configured, the WTRU may select the corresponding beam monitoring or failure detection resources which correspond to the indicated / current NES state of the concerned cells. The WTRU may perform beam monitoring with the updated failure detection resources (and associated configurations) to detect beam failure.

[0201] In examples, a WTRU may be configured with more than one FDR sets, e.g., for the case of multi-TRP, and it may receive an indication from the network about one or more of the FDR sets undergoing NES state. In examples, the WTRU may adapt its monitoring of the FDR sets for different TRPs according to the indication received from the network.

[0202] The WTRU may detect an anticipated Beam Failure. A WTRU may detect an anticipated beam failure. The anticipated beam failure may mean that the WTRU estimates a future beam failure may happen. The WTRU may detect the anticipated beam failure if the beam failure detection counter, BFD counter, reaches a certain threshold. In examples, the WTRU may be configured with a threshold to detect anticipated beam failure. In examples, the WTRU may be configured with one threshold to detect beam failure, called BFI_MAX_Count, and another threshold to detect anticipated beam failure. In examples, the WTRU may derive the threshold to detect anticipated beam failure from the beam failure detection threshold, BFI_MAX_Count. The WTRU may derive the threshold to be used for anticipated beam failure detection from BFI_MAX_Count using a specified rule. In examples, the rule may be as follows: Threshold = a + BFI_MAX_Count / b, where ‘a’ and ‘b’ are the parameters known to the WTRU. The WTRU may be configured with the parameters or they may be specified.

[0203] In examples, with a=0, b=2, the threshold for anticipated beam failure is half of the BFI_MAX_Count. In examples, with a=-2, b=1 , the threshold of anticipated beam failure is 2 less than the BFI_MAX_Count. In examples, two additional BFIs received from PHY layer will land the WTRU in the beam failure detection. In examples, there may be different values for parameters ‘a’ and ‘b,’ and the WTRU may select a set of values to derive the threshold based upon specified rule. The specified rule may be the value of the BFI_MAX_Count itself. As an example, if BFI_MAX_Count is larger than a specified value, the WTRU may use a (e.g., one) manner and a (e.g., one) set of values to derive the threshold for anticipated beam failure. If BFI_MAX_Count is not larger than that specified value, the WTRU may use a different manner and a different set of values to derive the threshold for anticipated beam failure.

[0204] The determination of the threshold for anticipated beam failure based upon BFI_MAX_Count may use different modeling compared to the equation above or may use parameters in a different manner.

[0205] In examples, a WTRU may detect anticipated beam failure based upon direct measurements over the RSs that it is monitoring for beam failure detection purpose. In examples, if the RSRP of the beam monitoring RS is below a certain threshold, the WTRU may detect an anticipated beam failure. If the WTRU is configured with more than one RS for beam monitoring purpose, the WTRU may detect an anticipated beam failure if the measured RSRPs for (e.g., all) the RSs in an (e.g., one) overlapping measurement interval falls below a threshold. In examples, the WTRU may detect an anticipated beam failure, if the measured RSRP for at least one of the beam monitoring RS falls below a threshold.

[0206] In examples, a WTRU may detect anticipated beam failure based upon cell level measurements. In examples, if the RSRP for the cell falls below a certain threshold, the WTRU may detect anticipated beam failure. The cell level measurements may be derived from the beam level measurements. The WTRU may perform filtering prior to comparing the cell level measurements with the configured threshold. The filtering may be L1 L2 filtering, L3 filtering, or a combination.

[0207] In examples, a WTRU may detect anticipated beam failure based upon its knowledge of cell being in network energy saving (NES) state. The WTRU may get the information of the cell being in the NES state through the same cell or through a different cell. The WTRU may be configured with different thresholds for different NES states of the cell it is performing beam monitoring. The WTRU may select the suitable set of anticipated beam failure configuration in association to the current NES state of the cell. In examples, the WTRU may determine the threshold to detect anticipated beam failure itself based upon the cell NES state. The WTRU may determine the threshold using a specified rule. For example, the determination of the values for the parameters ‘a’ and ‘b’ in the earlier example may be linked to the cell NES state. In examples, the parameters may take different values for different sleep cycles, or DTx durations, or DRx durations etc.

[0208] In examples, a WTRU may detect anticipated beam failure based upon its knowledge of network employing a (e.g., specific) set of failure detection resources. The set of failure detection resources may employ one of the NES techniques in time, frequency, power or spatial domains. In examples, the set of failure detection resources may have reduced number of resources compared to other set.

[0209] In examples, a WTRU may be configured with different beam failure detection parameters, e.g., BFI_Timer, BFI_MAX_Count values, RSRP threshold_BFR, RSRP_Threshold_SSB, or relevant parameters, for an NES state. In examples, the values may be absolute values. In examples, the values may be relative values as compared to a non-NES state (e.g., a value of 1, indicating that the BFI_MAX_Count for that NES state is lower than the BFI_MAX_Count for the non-NES state by 1).

[0210] A WTRU may transmit an anticipated beam failure indication. Upon detecting an anticipated beam failure, a WTRU may determine to transmit an indication to the network. The WTRU may determine to transmit the indication on a cell different from the one where it detects an anticipated beam failure. TheWTRU may determine to transmit the indication if the measurements on the cell are better than a threshold. In examples, if the WTRU determines to transmit the anticipated beam failure indication for cell 1 on cell 2, the WTRU may be allowed to transmit the indication (e.g., only) if RSRP of cell 2 is better than a configured threshold.

[0211] In examples, the WTRU may be configured to transmit the indication in a cell that belongs to a different cell group than the cell where the beam failure is anticipated. For example, the beam failure may be anticipated on cell 1 that belongs to the SCG, and the indication may be sent to a cell that belong to the MCG. In examples, the MCG cell to transmit the indication may be the PCell of the MCG. In another example, the MCG cell may be an SCell in the MCG.

[0212] In examples, a WTRU may be configured to transmit the indication on another cell group than the cell where the beam failure is anticipated if the beam failure is anticipated on the special cell. In examples, if the WTRU anticipates a beam failure on PSCell of the SCG, it may be configured to transmit the indication on one of the cells in MCG, e.g., PCell.In examples, the decision to transmit the indication to another cell that belongs to a different cell group may be based on the determination on the signal levels of one or more cells of the two cell groups. Examples may include: prioritizing transmitting the indication to a cell in the same cell group if there is a cell in that cell group that has a signal level above a certain threshold (e.g., RSRP > thresholdl); prioritizing transmitting the indication to a cell in a different cell group if there is a cell in the different cell group that has a signal level greater than the best cell in the same cell group (e.g., by more than a certain threshold); prioritizing transmitting the indication to a cell belonging to the cell group that has the best average cell quality; prioritize transmitting the indication to a cell belonging to the cell group that has the most number of cells above a certain threshold; etc.

[0213] In examples, a WTRU may determine to transmit anticipated beam failure indication to the network if the WTRU has been configured with more than failure detection resources. In examples, a WTRU may determine to transmit an anticipated beam failure indication to the network if the WTRU knows that the network is currently applying at least one of the NES techniques to the beams it is monitoring for beam failure detection purpose.

[0214] In examples, a WTRU may determine to transmit anticipated beam failure indication to the network if the network updated its NES state within a duration T. For example, the network update of NES state may have an impact on the beam monitoring signals that the WTRU is using, and the update may lead to degradation such that the WTRU is detecting compromised performance and leading to detection of anticipated beam failure indication.

[0215] The WTRU may determine to not transmit the indication if it already transmitted the indication for the same cell within a duration T1 and is expecting the response from the network. The WTRU maydetermine to not transmit the indication if it already transmitted the indication to the network within a duration T2 and has received a response from the network.

[0216] In examples, a WTRU may determine to transmit an anticipated beam failure indication if it detects anticipated beam failure for a group of cells. The group of cells may be known to the WTRU, e.g., through specification or pre-configuration. The network may configure the group of cells through explicit or implicit signaling. In examples, the group of cells may be the set of WTRU serving cells for which the network is employing one of the NES techniques. In examples, the group of cells may be the WTRU serving cells employing one of the NES techniques within a specific cell group (CG), e.g., in MCG or in SCG. The failure detection resources for the group of cells may be configured individually per cell, e.g., by configuring one or two FDR sets per cell. The FDR sets for the group of cells may be configured jointly in one or two FDR sets. An RS may be configured with the cell index to which it serves as FDR.

[0217] In examples, a WTRU may determine to transmit anticipated beam failure indication if it receives an indication from the network of at least one of the TRP undergoing one of the NES states or being muted. The condition may be combined with one of the earlier defined measurement conditions to detect anticipated beam failure. The gNB may indicate a change in SSBs on remaining (non-NES) TRPs, when the other TRP enters a partial or full muted / NES state. The indication may be based on the existing / remaining active TRP's beam granularity. For example, if the current beam(s) on remaining active TRP are not refined or alternately based on refinement that is updated with low frequency (CSI-RS resource set periodicity for the TRP was high), and the TRP that is about to be turned off had lower CSI-RS periodicity, the periodicity of the resource set on the remaining TRP(s) may be reduced. The network / gNB may provide an updated periodicity, or an aperiodic resource set may be triggered, resulting in WTRU performing beam monitoring / measurement.

[0218] The WTRU may transmit an anticipated beam failure indication. Upon detecting an anticipated beam failure, a WTRU may determine to transmit an indication to the network. The WTRU may determine to not transmit the indication to the network if it already transmitted the indication to the network within a duration T prior to current detection of anticipated beam failure.

[0219] Upon determining to transmit an indication of anticipated beam failure, the WTRU may transmit the indication through one of the following. The indication may be MAC CE based. A WTRU may transmit a MAC CE providing an indication of anticipated beam failure. The MAC CE may comprise of relevant information such as the cell ID of the cell for which WTRU detects an anticipated beam failure. The MAC CE may also carry the measured RSRPs of the RS(s). Transmitting the measured RSRP may be more useful for example when the WTRU detects an anticipated beam failure based upon RSRP value of the beam monitoring RSs.

[0220] The WTRU may transmit the MAC CE on a cell different from the one for which it detects anticipated beam failure. In examples, the WTRU may transmit MAC CE on the primary cell of the cell group for whose cell the WTRU detects an anticipated beam failure. In examples, the WTRU may be configured with the cell where it will transmit MAC CE indicating anticipated beam failure. In examples, the WTRU may be allowed to transmit MAC CE if it has been scheduled uplink resource for one of the cells. The scheduled uplink resource may be obtained through a dynamic grant or through a configured grant.

[0221] The indication may be SR based. A WTRU may transmit an SR to indicate detection of anticipated beam failure when the WTRU is configured with SR resources associated to the anticipated beam failure of a cell that it detects anticipated beam failure.

[0222] The indication may be UL WUS based. A WTRU may transmit an UL WUS to indicate its detection of anticipated beam failure for one of its serving cells. The WTRU may be provided with WUS configuration to indicate anticipated beam failure. The WUS resource may be on a cell different from the one where the WTRU detects an anticipated beam failure.

[0223] In examples, a WTRU may transmit the anticipated beam failure indication on the cell where it detects the anticipated beam failure according to the configured criterion. The cell may be one of the serving cells in a cell group. In examples, the cell may be the primary cell of the cell group.

[0224] In examples, a WTRU may transmit the anticipated beam failure indication on a cell different from the one for which WTRU has detected anticipated beam failure. The WTRU may determine to transmit anticipated beam failure indication on a cell which is pre-configured by the network for a purpose. In examples, the WTRU may transmit anticipated beam failure indication on the primary cell of the cell group comprising of the serving cell ‘x’ for which the WTRU detects anticipated beam failure.

[0225] In examples, a WTRU may be configured with a rule for how to determine the indication mechanism. For example, the WTRU may be configured with UL WUS for an anticipated beam failure indication. Upon detecting an anticipated beam failure, the WTRU may check if it has a valid grant within a specified duration T. If so, the WTRU may use the grant to transmit MAC CE based indication. Else, it will transmit UL WUS based indication.

[0226] A WTRU may be configured to transmit the indication for anticipated beam failure in the first available transmission occasion after detecting the anticipated beam failure. In examples, the first available occasion may be t seconds later or n symbols later after detecting the anticipated beam failure, t may be in seconds, milliseconds, or other suitable time units, n may be in terms of symbols, or a slot with a given subcarrier spacing. The offset specified in terms of t or n may provide the WTRU sufficient time to prepare the indication to be transmitted in the UL direction.

[0227] In examples, a WTRU may provide one or more of the following information as part of the anticipated beam failure indication: the cell ID for which WTRU is reporting the anticipated beam failure; abeam identity or identities for which the WTRU is reporting the anticipated beam failure(s); the identities (indices) of the one or more FDR sets or TRPs for which the WTRU is providing an anticipated beam failure indication; the (e.g., current) NES state of the cell under which the WTRU is reporting the anticipated beam failure; the indication (e.g., index, identity) of the current set of failure detection resources that the WTRU is currently using; the indication of one or more recovery beams that the WTRU requests that the network starts transmitting; the indication of one or more recovery beams that the WTRU requests the network to transmit with normal (non-NES) periodicity or other non-NES parameters; the indication of one or more target set of failure detection resources that the WTRU is requesting for the network to start transmitting after receiving the indication (e.g., the indication may be a flag, for examples, an identity, index, a binary flag if there are (e.g., only) 2 possible detection resources, etc.,) to switch to a different failure detection resource set; or the indication of a target NES state that the WTRU is requesting through the indication transmission. For example, the WTRU may request that the (e.g., current) cell comes out of the NES state by stopping using a given NES technique. In examples, the WTRU may indicate that the network stops using any NES technique for the cell.

[0228] The WTRU may suspend its BFD timers / BFI_counters. Upon detecting an anticipated beam failure for cell x, a WTRU may determine to suspend its BFD timer and BFI_Counter(s) for cell x. The WTRU may suspend BFD timer and BFLCounter for cell x a configured delay T later than its determination of anticipated beam failure for cell x. The value of T may be pre-specified or pre-configured to the WTRU. The value of T may be specified in absolute units of time, or it may be specified in the units of symbols or slots with a suitable reference sub-carrier spacing. The sub-carrier spacing may be the DL sub-carrier spacing that the RSs of cell x are being transmitted with, e.g., SSBs of the cell x.

[0229] In examples, a WTRU may suspend its BFD timer and BFLCounter when it determines to transmit anticipated beam failure indication for cell x. In examples, a WTRU may suspend its BFD timer and BFLCounter when it transmits anticipated beam failure indication for cell x. The actual time when the WTRU suspends the timers and counters may be before or after the transmit time of anticipated beam failure and can have a fixed / configured delay with respect to the transmit time of the anticipated beam failure. The transmit time of the anticipated beam failure may be the start time (sym bol / slot etc.) or the end time of the transmission carrying anticipated beam failure.

[0230] In examples, a WTRU may suspend its BFD timer and BFLCounter for cell x (e.g., only) if any of the following conditions are true: cell x is a primary cell of the cell group; cell x is not a primary cell of the cell group; cell x was configured with two sets of FDR resource sets, and the WTRU has been indicated to use the FDR resource set employing one of the NES techniques; cell x is employing one of the NES techniques in time, frequency, power or spatial domains.

[0231] The WTRU may receive the gNB response to its anticipated beam failure indication. A WTRU may receive an indication from the gNB from one of its serving cells in response to its uplink transmission of anticipated beam failure for (e.g., any of) its serving cells.

[0232] In examples, the network may provide an indication over the same cell over whose uplink resource a WTRU transmits the UL indication. In examples, the network may provide an indication using the resource of the cell for which anticipated beam failure is indicated earlier by the WTRU. In examples, the network may provide the indication using another cell (e.g., the primary cell of the cell group that the cell where the beam failure is anticipated belongs to). In examples, the network may provide the indication via a cell that belongs to a different cell group than the group of the cell where the beam failure was anticipated to occur.

[0233] The WTRU may expect the network response within a specified duration after the transmission of anticipated beam failure indication. The WTRU may receive any of the following information in response to its anticipated beam failure transmission: the network may start to transmit full set of beams. The set of beams may include SSBs and CSI-RS beams. The indication may provide the duration or the period of time during which the beams will be transmitted. That time may be pre-specified or indicated as part of the indication.

[0234] The WTRU may receive a candidate beam recovery RS from the pre-configured list which will be sweeped. The network may provide the list of RS, e.g., SSB indices, which may sweep in response to the WTRU indication. The SSB indices may belong to the same cell for which WTRU reported anticipated beam failure. In examples, the network may provide additional cells IDs and SSB indices which will be sweeped.

[0235] The WTRU may receive T_sweep_duration, a time duration within which recovery RS, or recovery beams may be transmitted. The time duration may be specified in suitable units, in absolute time, or in a number of slots with reference to a sub-carrier spacing.

[0236] The WTRU may receive (e.g., additional) parameters related to the transmission of on-demand recovery resources such as one or more of a T_burst_start (start of the burst in time), periodicity, F_burst_start (start of the burst in Freq / PRB), or BWP ID (e.g., a BWP ID different from WTRU active BWP ID may be indicated by the network) for the BF avoidance SSB Burst.

[0237] The WTRU may receive A flag indicating that the WTRU is to transmit an indication when recovery beams are no longer needed. In examples, the network may provide the flag when it does not provide sweep duration, and the recovery resources and candidate beams may be transmitted in a periodic manner until the WTRU indicates to the network that those recovery resources are no longer needed.

[0238] The WTRU may receive the current NES state of the network (e.g., as part of the response to anticipated beam failure transmission).

[0239] The WTRU may receive the target NES state of the network that the network is going to activate after informing the WTRU. The target NES state may be indicated along with the start time of activation. The network may (e.g., instead of specifying the start time for the target NES state) provide a delay (e.g., time duration) after the network will activate the target NES state. The delay may be indicated between the WTRU receiving the network indication and the activation time for the target NES state. The start time, delay, and parameters related to the target NES state activation may be pre-specified and may be known to the WTRU. The network may provide the parameters related to the activation (e.g., explicitly) as part of the indication.

[0240] The WTRU may receive the set of failure detection resources that the network is using currently. The WTRU may receive the set of failure detection resources that the network is going to switch to.

[0241] In examples, the WTRU may be pre-configured with different configurations comprising one or more of the parameters / information-elements above (e.g., associated with a configuration identity or index), and the indication received from the network may be the index / identity of the configuration to be used by the WTRU (e.g., for the beam failure recovery).

[0242] The WTRU may receive the network response in the form of MAC CE. For example, the network may provide the indication as part of MAC signaling.

[0243] In examples, the WTRU may receive the network response in a DCI. The DCI may be addressed to the WTRU as a dedicated or a group common DCI as per the configuration.

[0244] In examples, the WTRU may receive the network response in an RRC signaling (e.g., dedicated / unicast RRC message, broadcast message such as SIB, etc.).

[0245] In examples, the signaling of the network response may be linked to the signaling of the WTRU transmitted anticipated beam failure. For example, the network may use a MAC CE based response if the WTRU transmitted MAC CE based UL indication, and the network may choose DCI based indication if the WTRU transmitted UL indication in the form of SR or an UL WUS. In examples, a different association of UL indication to DL response may be used.

[0246] In examples, the network may not transmit an explicit response to the WTRU after receiving anticipated beam failure indication. The WTRU may be configured to expect the DL transmission of recovery resources in response to its UL transmission of anticipated beam failure. The WTRU may be configured or pre-specified to expect the transmission of recovery resources (beams) with the normal periodicity starting no later than a time T after its UL transmission. The UL transmission time may be taken to be the last symbol or the last slot where the WTRU transmits the UL indication. The WTRU may know through pre-configuration or pre-specified the parameters with which the recovery resources can be transmitted. For example, the WTRU may be pre-configured to expect that after the transmission of ULindication, the network may start to transmit the recovery beams / resources with a given periodicity for a given specified duration.

[0247] In examples, the anticipated beam failure indication from the WTRU for a given cell, cell x, may result in that cell stopping the use of employed energy saving technique. As an example, if the cell x was employing an NES technique (e.g., using one or more of temporal, spatial, frequency, power, DTx / DRx adaptation), and the WTRU may transmit anticipated beam failure for cell x. The WTRU may expect the cell to move to normal (e.g., non-NES) state no later than a specified / configured duration after its anticipated beam failure indication.

[0248] In examples, upon receiving anticipated beam failure indication for cell x from the UE, the gNB may schedule SRS (e.g., either periodic or trigger aperiodic SRS) transmission for the WTRU. The scheduled SRS transmission may be for one TRP, all TRPs, one cell or for all cells. In examples, this may be enabled for a TRP that may be about to enter an inactive DTX state where it may not be transmitting DL control information. The TRP may switch to sweeping through its receive beams to find best Rx beam. The TRP may know the best Tx beam (e.g., via reciprocity / correspondence) allowing WTRU to maintain a measure of beam refinement when the TRP is in NES / DTX off state. Specific SRS resource sets may be used for this which can be periodic or aperiodic. For periodic SRS resource sets, periodicity may be based on TRPs DTX cycle. With the SRS transmission from the WTRU, the network may determine the best DL beams for the WTRU. The beams may be used to transmit FDR sets, candidate recovery beams, on- demand FDR / recovery resources, or sweep of suitable set of beams for the WTRU. The network may provide the WTRU with the updated information about the resources it’s going to transmit for the particular WTRU.

[0249] The WTRU may resume its BFD timers / BFI_counters. Upon receiving a response from the network after its transmission of anticipated beam failure for cell x, a WTRU may determine to resume its BFD timer and BFLCounter for cell x. A WTRU may determine to resume its BFD timer and BFD_Counter for cell x (e.g., only) if they are currently in a suspended state.

[0250] In examples, a WTRU may reset the BF related timers and counters upon receiving the response from the network to its transmission of anticipated beam failure indication for cell x. As an example, the WTRU may reset the BFD timer and restart the BFLCounter from its initial value of ‘O’.

[0251] In examples, a WTRU may resume or reset the BF timers and counters based upon the network response to its anticipated beam failure indication for cell x according to the (pre-)configuration. In examples, the WTRU may be configured to reset the timers / counters if the network provides a response of changing the NES state of the cell x to normal state and restart the timers / counters otherwise. In examples,the WTRU may be configured to reset the timers / counter if the network provides on-demand sweep of failure detection resources or recovery resources and resume otherwise.

[0252] In examples, a WTRU may resume its BFD timer and BFD_Counter a fixed / configured delay T after receiving the network response to it anticipated beam failure of cell x. The receive time of the network response may be the start time (symbol / slot, etc.) or the end time of the transmission carrying the network response to anticipated beam failure.

[0253] In examples, a WTRU may resume its BF timers and counters if it does not receive a response from the network within a configured delay after transmitting anticipated beam failure indication. The WTRU may measure the recovery beams after receiving the network response.

[0254] A WTRU may start monitoring the recovery beams after its UL transmission of anticipated beam failure for cell x. The WTRU may start monitoring the recovery beams after having received the response from the network if the WTRU is programmed to receive a response from the network. The WTRU may monitor the recovery beams with the (e.g., normal) periodicity of the recovery beams. If the network provides an updated periodicity and other parameters associated to the recovery RS transmissions, or if a special set of parameters have been specified to be used by the network after receiving an anticipated beam failure, the WTRU may use the provided / specified parameters to monitor the recovery beams / resources.

[0255] If the network provides explicit resources, e.g., in terms of SSB indices etc., the WTRU may monitor the resources in addition to the recovery beams configured for beam failure recovery purpose. In examples, a WTRU may be configured to monitor (e.g., only) the newly provided recovery resources. In examples, the network response may provide the indication if the WTRU follows the earlier configured recovery resources, newly provided recovery resources, or a combination of both. The combination may be a subset of one or both, for example.

[0256] The WTRU may select a suitable recovery resource beam. A WTRU may select a suitable recovery resource / beam among the recovery resources / beams it monitors. The WTRU may select the recovery beam with the highest measured RSRP. In examples, the WTRU may be configured to perform filtering over more than one measured value prior to selection. For example, the WTRU may average a given number of values. In examples, different filtering coefficients / weights may be specified to be used by the WTRU. In examples, the WTRU may be configured to prioritize a resource or a set of resources. For example, the WTRU may be configured to apply an offset to the measured values to (de-)prioritize a (set of) resources.

[0257] In examples, a WTRU may select multiple recovery beams. In examples, a WTRU may report multiple recovery beams for its active antenna panel. In examples, a WTRU may select one or more recovery beams for its available antenna panels. In examples, a WTRU may report multiple recoverybeams for a single TRP, or at least one recovery beam for its active TRP. The WTRU may enable / disable antenna panels for group-based reporting. This may be a function of whether WTRU was connected to one or more beams on the TRP (and the beams were impacted by NES state change). For example, a WTRU that has two (or more) antenna panels active for group-based reporting with multi-TRP may disable one or more panels. This may be conditioned on SINR / RSRP of remaining TRP. If the Rx RSRP of the (NES- state) TRP was better than that of the remaining (e.g., non-NES state) TRP(s), the WTRU may keep (e.g., all) of its panels on (for better diversity); If (e.g., NES-state) TRP had poor SINR and there is a strong signal from remaining TRP(s), the WTRU may turn off panels to reduce power consumption (with no impact on service).

[0258] The WTRU may measure the updated failure detection resources after receiving the network response. A WTRU may start monitoring the network indicated beams (or failure detection resources) after its UL transmission of anticipated beam failure for cell x. The WTRU may start monitoring the failure detection resources after having received the response from the network if the WTRU is programmed to receive a response from the network. The WTRU may monitor the beams through failure detection resources with the network indicated periodicity of the resources. If the network provides an updated periodicity and other parameters associated to the FDR RS transmissions, or if a special set of parameters have been specified to be used by the network after receiving anticipated beam failure, the WTRU may use the provided / specified parameters to monitor the FDR resources.

[0259] A WTRU may start to monitor a set of FDR which is indicated in the network response to UL transmitted anticipated beam failure. A WTRU may start to monitor a set of RSs for beam monitoring with non-NES parameters if the network indicates implicitly or explicitly in its response that it is stopping the use of NES technique for the cell WTRU reported anticipated beam failure.

[0260] A WTRU may start to monitor a set of RSs for beam monitoring with updated NES parameters if the network indicates switching to a given NES state. If the network provides explicit resources, e.g., in terms of SSB indices, etc., the WTRU may monitor the resources in addition to the FDRs configured for beam failure detection purpose. In examples, a WTRU may be configured to monitor (e.g., only) the newly provided FDR resources. In examples, the network response may provide the indication if the WTRU follows the earlier configured FDR resources, newly provided FDR resources, or a combination of both. The combination may be a subset of one or both, for example.

[0261] The WTRU may transmit a UL indication. After monitoring the resources relevant for beam failure detection, the WTRU may determine to transmit a UL indication. The resource relevant for beam failure detection may be the failure detection resources that the WTRU monitors to detect beam failure, candidate recovery beams, on-demand failure detection resources, on-demand recovery resources, SSB beams, or CSI-RS beams.

[0262] A WTRU may determine to transmit a beam failure indication to the network for cell x if the BFD_Counter for cell x reaches a config ured / specified threshold BFI_MAX_Count. The WTRU may provide the selected recovery resource reference as part of the beam failure indication. In examples, the WTRU may transmit a beam failure indication on the same cell where it transmitted an earlier anticipated beam failure.

[0263] If a WTRU transmitted anticipated beam failure indication to the network for cell x upon certain conditions getting fulfilled, and if later BFD_Counter for cell x gets reset, e.g., due to BFD_Timer getting expired, the WTRU may transmit an indication to the network. The transmission of a UL indication may be conditioned if the network provided on-demand recovery resources, or the network requested an indication from the WTRU when it does not need recovery resources. The transmission of a UL indication may be further conditioned on the measurements made by the WTRU on the signals received for cell x for which it transmitted anticipated beam failure earlier. The measurements in question may be beam level measurements or cell level measurements.

[0264] The UL indication may be transmitted as PHY, MAC or RRC signaling. As part of the indication, the WTRU may provide one or more of the following: the cell ID, the IDs of recovery resources, the latest measurements on beams / cell, e.g., RSRP measurements, etc.

[0265] In examples, a WTRU may transmit RACH on the same cell where it detects beam failure. This may be the case, for example, if the cell is the primary cell of its cell group. The WTRU may determine a RACH occasion and other parameters for the transmission of RACH preamble according to its selected recovery / candidate beam.

[0266] Features described herein may be associated with a carrier aggregation (CA) pre-beam failure indication, e.g., with on-demand recovery resources. In examples, a WTRU may provide a pre-BF indication to the NW (e.g., the WTRU may provide a pre-BF indication before BF detection). In response, the NW may trigger a sweep (e.g., an on-demand sweep) of recovery beams (e.g., recovery beam reference signals (RSs)) for which the gNB provides the time / freq / RS details. The WTRU may measure the recovery beams from the sweep and indicate a suitable beam (e.g., a beam that satisfies a condition) to the network for recovery.

[0267] Failure detection resources (FDR) may be configured. The NW may have turned off the neighboring recovery beams to save energy (e.g., no WTRUs in neighboring beams). The WTRU may be connected to a first cell (e.g., such as an SpCell) and to a second cell (e.g., an SCell). The WTRU may be configured with the following for the 2nd cell. The WTRU may be configured with a set of failure detection resources (FDR) for beam failure detection. The WTRU may be configured with a set of recovery beams for beam failure recovery. The recovery beams may be undergoing NES (e.g., time / spatial / power domain).The WTRU may be configured with a set of SR resources and / or UL wake up signal (WUS) resources (e.g., an uplink indication configuration) to provide a pre-beam failure indication.

[0268] The WTRU may report (e.g., transmit to a network node / gNB) a pre-BF indication if BFD_counter on the 2nd cell (e.g., a beam failure detection counter value) > Threshold 1 (e.g., a first threshold) (where Thresholdl < BFI_MAX_Count) (e.g., BFI_MAX_Count may be a second threshold). The WTRU may receive an indication (e.g., the indication may be associated with network transmission) from the gNB over the 1st cell providing any of the following information (e.g., information associated with network transmissions). The information may include a candidate beam recovery RS (e.g., synchronization signal block (SSB)) from a pre-configured list which will be sweeped (same or different cell) (e.g., the information may include a sweep of on-demand SSB transmissions). The information may include T_sweep_duration, a time duration within which a recovery RS of the 2nd cell will be transmitted. The information may include T_burst_start (start of the burst in time), periodicity, and / or F_burst_start (start of the burst in Freq / PRB) for the BF avoidance SSB Burst. A different bandwidth part (BWP) ID may be indicated by the network. The information may include recovery beams and FDRs. The information may include a flag indicating that the WTRU is to transmit an indication if recovery beams are no longer needed. The WTRU may monitor and / or measure the recovery beams (e.g., the RSs associated with the network transmissions) in the sweep according to the gNB indication. The WTRU may select a suitable recovery beam based on the measurement(s) of the RS(s), for example., the WTRU may select a recovery beam that satisfies a threshold (e.g., a third threshold), where, in examples, the recovery beam satisfying the threshold may be determined by the recovery beam being better than the threshold (e.g., based on the measurement(s)).to the WTRU may report the suitable beam and / or measurement(s) to the NW. The WTRU may transmit an indication (e.g., to the network) on the 1st cell (e.g., using a resource from the 1st cell) comprising of the following (e.g., the WTRU may transmit the indication based on the measurement of the RSs). If (BFD_counter >= BFI _MAX_Count), an indication, via a BFD MAC CE, with the suitable recovery beam (e.g., selected recovery beam) on a 2nd cell may be transmitted to the network. If (BFD_counter resets and 2nd Cell RSRP > Thresholds) (e.g., if the FDR resources satisfy a fourth threshold), an indication that indicates that recovery beams (and / or on-demand sweeps) are no longer needed (e.g., for the 2nd cell) may be transmitted to the network (e.g., using the 1st cell).

[0269] Beam failure may be avoided by SSB burst adaptation. In examples, upon network (NW) adaptation of an SSB burst, and upon determining that a WTRU is at risk of beam failure, the WTRU may provide a pre-beam failure (pre-BF) indication to the network node / gNB requesting a set of SSB transmissions. In response, the network node / gNB may switch to a full SSB transmission (e.g., narrow beam SSBs / FDRs).

[0270] FIG. 6 illustrates a: WTRU anticipating BF after cell applying spatial NES adaptation. As shows in FIG. 6, the WTRU may use (e.g., normal) beams, shown by horizontal lined pattern as FDR.

[0271] In examples, the WTRU may be configured to use network energy saving (NES) beams (e.g., wider beams with potentially low power) as FDRs. Upon determining that a beam failure detection counter value (e.g., BFD_counter) reaches a first threshold (e.g., Thresholdl), the WTRU may request non-NES FDR. The WTRU may be connected to a first cell (e.g., a serving cell, such as an SpCell). The WTRU may be configured with the following.

[0272] The WTRU may be configured with a first set of full SSBs for FDR and a second (NES) set of FDR (e.g., a reduced number of SSBs or lower spatial / power beams) for beam failure detection (BFD), as well as an indication of an active set. In addition, the WTRU may be configured with a set of recovery beams for beam failure recovery. The WTRU may also be configured with an uplink (UL) indication configuration (e.g., SR / MAC-CE / UL WUS) to request switching to the first (normal) FDR set or an on- demand SSB transmission.

[0273] If the BFD_counter on the SpCell (e.g., the beam failure detection counter value for the first cell) exceeds the first threshold (Thresholdl) and remains less than a second threshold (e.g., BFI_MAX_Count), and if the second set of FDR is currently active, the WTRU may transmit an uplink indication (e.g., SR, MAC-CE, or UL WUS) on the serving primary cell (SpCCell) to request activation of the first set of failure detection resources.

[0274] The WTRU may receive, from the network node / gNB, an indication (e.g., via MAC signaling or DCI) of the activation of the first set of failure detection resources or on-demand (full) SSB (which may apply to one or more cells, such as a first cell or a second cell).

[0275] If on-demand SSB or the first set of FDR are received and at least one measured beam is determined to be above a threshold (e.g., a fourth threshold), the WTRU may provide an indication of the preferred beam and / or may request activation of the first (normal) set of FDR (e.g., via an indication to the network node / gNB).

[0276] The WTRU may start monitoring the first FDR set upon receiving the network indication. If the beam failure detection counter value (BFLCOUNTER) for the SpCell is greater than or equal to the second threshold (e.g., BFI _MAX_Count), the WTRU may transmit a Random Access (RACH) procedure carrying a beam failure recovery MAC control element (MAC CE) on the SpCCell. This transmission may include measurements obtained from the recovery beams that the WTRU used to determine a suitable beam for recovery.

[0277] A WTRU may perform beam monitoring through signals from multiple cells. For a WTRU connected to a serving cell, the WTRU may be configured to monitor one or more reference signals with agiven periodicity to detect beam failure on that serving cell. The serving cell may be the primary cell, SpCell, of the cell group. The reference signals may be SSBs, CSI-RS or (e.g., suitable) reference signals.

[0278] In examples, a WTRU may be configured with beam monitoring signals from more than one cell to perform beam failure detection over one of its serving cells. For example, to perform beam failure detection over cell x, the WTRU may be configured with reference signals from cell x and another cell y. The cell y may be a serving or non-serving cell for the WTRU. In examples, cell y may be a primary cell of the cell group comprising of cell x. In examples, to perform beam failure detection over cell x, the WTRU may be configured with reference signals from two different cells y and z. The cells y and z may be serving or non-serving cells for the WTRU. In examples, to perform beam failure detection over cell x, the WTRU may be configured with reference signals from another cell y. The cell y may be a serving or non-serving cell for the WTRU. In examples, cell y may be a primary cell of the cell group comprising of cell x.

[0279] In examples, cell x may be configured to apply one of the network energy saving NES techniques, e.g., in time, frequency, power or spatial domains.

[0280] In examples, to perform beam failure detection for its serving cell x, a WTRU may be provided two configurations. An example may be applied when the cell x is in a (e.g., normal) state, e.g., not applying an (e.g., specific) NES technique. An example configuration may be applied when the cell x is applying an NES techniques. An example configuration may include the failure detection resources FDR from cell x itself to perform beam failure detection. An example configuration may include one or more sets of the FDRs where the FDR sets may belong to the following cells: 1 set of FDRs from cell x and 1 set of FDRs from cell y; 1 set of FDRs from cell y and 1 set of FDRs from cell z; 1 set of FDRs from cell y.

[0281] Where cells y and z may be serving or non-serving cells for the WTRU. In examples, one of cells y and z may be the primary cell of the cell group comprising cell x. To perform beam failure detection, a WTRU may be configured with beam failure detection timer, BFD_Timer, and BFD_MAX_Count values.

[0282] In examples, a WTRU may be configured with beam failure detection timer, BFD_Timer, and BFD_MAX_Count values for an FDR set, e.g., BFD_Timer1 and BFD_MAX_Count1 for FDR set 1 and BFD_Timer2 and BFD_MAX_Count2 for FDR set 2.

[0283] A WTRU may detect a Beam Failure through independent BF Counters. A WTRU may detect a beam failure for cell x while it is monitoring the FDRs from one or more sets. In examples, to perform beam failure detection over cell x, when a WTRU is configured with FDR set 1 from RS of cell x and FDR set 2 from RS of cell y, the PHY layer at the WTRU may generate independent beam failure instances (BFI) for cell x and cell y. The MAC layer at the WTRU may maintain independent BF counters, BFI_Counter1 for FDR set 1 and BFI_Counter2 for FDR set 2. The WTRU may detect a beam failure for cell x when BFI_Counter1 and BFI_Counter2 exceed their respective configured thresholds as in the following:BFI_counter1 (counting BFIs on RSs from FDR set 1) >= BFD_MaxCount1; and / or BFI_counter2 (counting BFIs on RSs from FDR set 2) >= BFD_MaxCount2.

[0284] In examples, the WTRU may be configured to detect beam failure for cell x when both conditions get fulfilled simultaneously (e.g., when RSs from both FDR sets are being transmitted, and the cell x may be applying some form of time domain NES). The time domain NES technique applied by the cell x may be DTx / DRx, or it may be reduced periodicity of transmissions for signals / RSs part of its FDR.

[0285] In examples, the WTRU may be configured to detect beam failure for cell x when any one of the above conditions gets satisfied, e.g., any of the BFI_counter1 / 2 operating on FDR set reaches its configured BFD_MAX_Count1 / 2. The design may be useful when the network intends to put cell x to sleep for longer intervals of time. When the network intends to put cell x to deep sleep interval, the WTRU may (e.g., still) monitor the signals from FDR set 2 if FDR set 1 comprises of signals from cell x. In that case, BFI_counter2 still keeps on running, and if it reaches the associated BFD_MaxCount2, the WTRU may detect beam failure for cell x.

[0286] The WTRU may detect a beam failure through a single BF counter and independent BFIs for FDR sets. A WTRU may detect a beam failure for cell x while it is monitoring the FDRs from one or more sets. In examples, to perform beam failure detection over cell x, when a WTRU is configured with FDR set 1 from RS of cell x and FDR set 2 from RS of cell y, the PHY layer at the WTRU may generate independent beam failure instances (BFI) for cell x and cell y. The MAC layer at the WTRU may maintain a single BF counter, BFLCounter, which is incremented from PHY generated BFIs from FDR set 1 and FDR set 2. In examples, the WTRU may be configured to increment the BFLCounter from BFI from FDR set 1 and BFI from FDR set 2 as in the following:

[0287] BFLCounter [n+1 ] = BFLCounter [n] + 1 / x (if BFI generated on FDR Set 1) + 1 (if BFI generated on FDR set 2),

[0288] where x is a parameter configured by RRC. [n] in the above equation captures the notion of time, such that BFI_Couner[n+1] indicates the value of BFLCounter at instant ‘n+1’ computed from its previous value BFI_counter[n] at instant ‘n’. The time, is not limited to be periodic, and n+1 may mean an instant which comes after an instant n. The time instants may indicate the instants whenever change happens in BFLCounter value, e.g., due to BFI received from PHY layer generated over FDR Set 1 or FDR Set 2.

[0289] The WTRU may detect a beam failure for cell x when BFLCounter reaches its configured threshold as in the following: BFLcounter >= BFD_MaxCount.

[0290] The WTRU may detect a beam failure through a single BF counter and PHY based BFI generation over multiple FDR sets. A WTRU may detect a beam failure for cell x while it is monitoring the FDRs from one or more sets. In examples, to perform beam failure detection over cell x, when a WTRU is configured with FDR set 1 from RS of cell x and FDR set 2 from RS of cell y, the PHY layer at the WTRUmay generate a (e.g., single) joint beam failure instances (BFI) which is used to increment the BFD_Counter for cell x. The MAC layer at the WTRU may maintain a single BF counter, BFLCounter, which is incremented from PHY generated BFIs from FDR set 1 and FDR set 2. In examples, the WTRU is configured to increment the BFLCounter by 1 when it receives a from BFI from PHY layer for cell x. The WTRU may detect a beam failure for cell x when BFLCounter reaches its configured threshold as in the following: BFLcounter >= BFD_MaxCount. In examples, the PHY layer at the WTRU may generate a BFI for cell x when the measured RSRP for (e.g., all) the FDRs in set 1 are below a 1stconfigured threshold, RSPR1, and the measured RSRP for all the FDRs in set 2 are below a 2ndconfigured threshold, RSRP2. The design may apply (e.g., may be useful) when the RSs from both sets are being transmitted, for examples, with a different periodicity.

[0291] In examples, the PHY layer at the WTRU may generate BFI for cell x when the measured RSRP for all the FDRs in set 1 are below a 1stconfigured threshold, RSPR1 , or the measured RSRP for all the FDRs in set 2 are below a 2ndconfigured threshold, RSRP2. The design may be applied (e.g., may be useful) when the RSs from both sets are not being transmitted simultaneously.

[0292] The WTRU may determine the interval to generate BFI through a set of rules. The set of rules may be pre-specified or provided to the WTRU through network configuration. The set of rules may include the minimum time duration and maximum time duration for BFI generation. The BFI generation and intervals may change as a function of WTRU being in energy saving mode, e.g., DRx. The BFI generation and intervals may change as a function of network / cell being in energy saving mode, such as network applying any of the time, frequency, power or spatial energy saving techniques.

[0293] The WTRU may select an appropriate beam failure detection method. A WTRU may select an appropriate beam failure detection method to apply for cell x when it is configured to monitor RSs from multiple related cells to detect beam failure for cell x. The methods may include one or more examples described herein, e.g., the WTRU maintaining independent BF counters for multiple cells, a (e.g., single) BF counter and per-cell BFI generation from PHY layer, or a (e.g., single) BF counter and a (e.g., single) combined BFI generation from PHY layer over multiple related cells, or fall back to BF detection based upon RS from a single cell, etc. The network may configure any of the methods described herein to detect beam failure for cell x. In examples, the methods to detect beam failure may be pre-specified.

[0294] A WTRU may select an appropriate beam failure detection method based upon a set of specified rules. In examples, the rules to select a BF detection method for cell x may depend on whether cell x is applying one of the NES techniques. For example, if cell x is applying (a given) NES technique, the WTRU will select one of specified / configured BF method based upon monitoring RS from multiple cells (e.g., cell x and another related cell), and counting / detecting beam failure based upon BFI from the cells. If the cell x is not applying any NES technique, the WTRU may select BF detection method for cell x.

[0295] In examples when the cell x is applying one of the NES techniques, the WTRU may be specified a set of rules to select an appropriate BF detection method over multiple methods detecting beam failure for cell x over FDRs from multiple cells. In examples, a WTRU may be specified different methods for different NES techniques, e.g., selecting a given method when the cell x is applying time domain NES technique, and selecting a (e.g., different) method when the cell x is applying spatial (or power) domain NES technique. A plurality of methods may be specified to be used for a plurality of NES techniques used in cell x.

[0296] In examples, a WTRU may be specified multiple BF detection methods using FDRs from multiple related cells when the cell x is applying an (e.g., one specific) NES technique, e.g., time domain NES technique. In examples, the WTRU may be specified a set of rules to select an appropriate BF detection method based upon the time domain NES technique parameters. In examples, if the cell x is applying time domain NES technique, e.g., DTx with periodicity within a given range [T1 , T2], and inactive time within another range |T3, T4], the WTRU may select a first BF detection method over FDRs from multiple cells. If DTx parameters do not fall in the specified range, the WTRU may select a second BF detection method over FDRs from multiple related cells. In examples, (e.g., only) the DTx periodicity or the DTx inactive time, or the DTx active time may be used as rules to select appropriate BF detection method over FDRs from multiple related cells.

[0297] In examples, when a BF detection method with FDRs from multiple related cells has been selected by a WTRU based upon a set of rules, the parameters used for the selected method may be based upon the NES parameters for the cell x, and or NES parameters for the other related cell. The BF detection method specific parameters may comprise of any of the following: the parameters to generate BFI per cell, the parameters to generate BFI jointly over multiple cells, BFD_MAX_Count per cell or joint value, the parameter to combine BFIs of multiple cells to increment fractionally BFLCounter, etc.

[0298] In examples, the network may configure the WTRU with (e.g., different) BFD to use for (e.g., different) NES techniques or (e.g., different) NES states. For example, for BFD association with (e.g., different) NES techniques, the configuration may specify BFD to be used for power domain NES techniques and BFD (e.g., another BFD) for cell DTx / DRx based NES techniques. In examples of BFD association with NES states, the (pre-)configuration may specify a (e.g., one) BFD for NES state A and a (e.g., different) BFD for NES state B. The network may configure the BFD method to use explicitly or implicitly for (e.g., different) NES states or (e.g., different) NES techniques.

[0299] The WTRU may measure the recovery beams. A WTRU may measure and monitor the candidate recovery beams for cell x. A WTRU may be configured with one or more sets of candidate recovery beams for cell x. In examples, a WTRU may be configured different sets of recovery beams for different NESstates of cell x. In this case, the WTRU may monitor the beams in appropriate recovery set which correspond to the actual NES state of cell x.

[0300] In examples, a WTRU may be configured with one or more sets of candidate recovery beams for cell x. A first set of recovery beams may correspond to FDR Set 1 , and a second set of recovery beams may correspond to FDR Set 2. The WTRU may be configured to use the set of recovery beams corresponding to the active FDR set. For example, if the WTRU is using FDR Set 1 (2), the WTRU may use the set of recovery beams which is linked to the FDR Set 1 (2).

[0301] The WTRU may start monitoring the recovery beams after or before detecting the beam failure on cell x. In examples, the WTRU may start to monitor the recovery beams when BFD_Counter reaches a specific value. The WTRU may monitor the recovery beams with the (e.g., normal) periodicity of the recovery beams.

[0302] A WTRU may select a suitable recovery resource or recovery beam. A WTRU may select a suitable recovery resource / beam among the recovery resources / beams it monitors. The WTRU may select the recovery beam with the highest measured RSRP. In examples, the WTRU may be configured to perform filtering over more than a (e.g., one) measured value prior to selection. For example, the WTRU may average a given number of values. In examples, different filtering coefficients / weights may be specified to be used by the WTRU. In examples, the WTRU may be configured to prioritize a resource or a set of resources. For example, the WTRU may be configured to apply an offset to the measured values to (de-)prioritize a (set of) resources.

[0303] In examples where a WTRU is configured with more than one set of candidate recovery beams, the WTRU may be configured with different selection criteria for different sets. In examples, the WTRU may be configured to select a beam (e.g., only) from the active recovery set, as outlined in the previous embodiment. In examples, the WTRU may be configured with different thresholds, e.g., RSRP thresholds, for the recovery beams in different sets.

[0304] The WTRU may transmit a UL indication. After monitoring the resources relevant for beam failure detection, a WTRU may determine to transmit an UL indication. The resource relevant for beam failure detection may be the failure detection resources that WTRU monitors to detect beam failure, candidate recovery beams, on-demand failure detection resources, on-demand recovery resources, SSB beams, or CSI-RS beams.

[0305] A WTRU may determine to transmit a beam failure indication to the network for cell x if the WTRU has detected beam failure for cell x according to the configured criteria. The WTRU may provide the selected recovery resource reference as part of the beam failure indication. The UL indication may be transmitted as PHY, MAC or RRC signaling. As part of the indication, the WTRU may provide one or more of the following: the cell ID, the active FDR set, the selected criterion to detect beam failure, the selectedset of recovery candidates, the IDs of recovery resources, the latest measurements on candidate beams / cell, e.g., RSRP measurements, etc.

[0306] A WTRU may transmit RACH on the same cell where it detects beam failure, for example, if the cell is the primary cell of its cell group. The WTRU may determine a RACH occasion and other parameters for the transmission of a RACH preamble according to its selected recovery / candidate beam.

[0307] In examples, a WTRU may transmit a beam failure indication as a MAC CE over the primary cell of cell group including cell x, where a WTRU has detected a beam failure for cell x. Cell x may not be the primary cell of the cell group for the WTRU.

[0308] Beam failure may be detected across multiple related cells (e.g., anchor and non-anchor). The gNB may configure a WTRU with beam failure detection resources for cell 1 using the RSs from cell 1 and cell 2 (cell 2 may or may not be a serving cell). The WTRU may perform weighted increment of beam failure counter over cell 1 BFIs and cell2 BFIs to determine BFD for cell 1 .

[0309] In examples, the NW may configure the WTRU to use the FDRs from two cells (e.g., co-located cells) to perform BFD on one cell. A WTRU may at least be connected to a 1st cell, cell 1 , applying one of the NES techniques.

[0310] The WTRU may be configured with the following for the beam failure detection over the 1 st cell. The WTRU may be configured with a 1st set of failure detection resources (FDR) over the RSs from the 1st cell. The WTRU may be configured with a 2nd set of failure detection resources (FDR) over the RSs from a 2nd cell, Cell2, where Cell2 may be a serving cell or a non-serving cell for the WTRU. The WTRU may be configured with a set of recovery beams for beam failure recovery purpose for the 1st cell. The WTRU may make the measurements of 1st set of FDR and 2nd set of FDR. The PHY layer at the WTRU may generate BFI for cell 1 if the FDR in the 1st set are less than a threshold RSRP1 , and BFI for cell 2, if (e.g., all) the FDR in 2nd set are less than a threshold RSRP2.

[0311] The WTRU may determine BFD based upon BFD_counter exceeding the BFD_MaxCount where the BFD_counter counts failures from BFI of both cells received from PHY and weights the counts.

[0312] BFLcounter (n+1) = BFLcounter (n) + 1 / x (if BFI on celH) + 1 (if BFI on cell 2) where x= configured by RRC.

[0313] Upon determination of BFD on cell 1 , the WTRU may perform the BF recovery procedure by (a) transmitting a RACH if CelH is an SpCell, (b) by transmitting beam failure recovery MAC CE on the SpCell if CelH is a non-SpCell.

[0314] BFD may use multiple configurations through NES based configuration selection. The WTRU configuration may include 2 or more sets of failure detection sources. A 1 st / 2nd set of failure detectionresources, BF detection timers / counters, for beam failure detection in a mode (e.g., normal mode) / NES mode.

[0315] The WTRU may be configured with multiple BFD / FDR sets. A set may be configured with at least one of the following: BFD resources (e.g., CSI-RS or SSBs to measure for BFD); a BFD timer or time value, BFI counter, BFD max count value (used for triggering BFR), e.g., beamFailureDetectionTimer, beamFailurelnstanceMaxCount, beamFailureRecoveryTimer, BFLCOUNTER, etc.; one or more BFR reporting resources or frequencies (e.g., PUCCH or PRACH); one or more of an applicable / associated NES state (e.g., a given cell DTX configuration, a certain SSB periodicity, a power / spatial domain adaptation state, etc.), or an applicability in a non-NES state (e.g., when cell DTX is deactivated or when SSBs / CSI-RS are transmitted at their regular full power periodicities); a channel measurement condition (e.g., an RSRP range or threshold), for example, rsrp-ThresholdSSB, rsrp-ThresholdBFR, etc.; a set of recovery beams for beam failure recovery where the recovery beams may be applying NES in time domain (time / spatial / power domain) (e.g., , candidateBeamRSList, candidateBeamRS-List-r16, candidateBeamRS- List2-r17, etc.) (e.g., such may be configured independently of the BFD set (e.g., for all BFD sets)); a UL WUS, RACH, or SR configuration for requesting appropriate BFD / BFR configuration and on-demand RS or for indicating a BFR or a pre-BFR indication (e.g., such may be configured independently of the BFD set (e.g., for all BFD sets)); RA related parameters (e.g., during RACH triggered for a BFR of an SpCell). For example, power ramping parameters, such as powerRampingStep, powerRampingStepHighPriority, preambleTransMax, scalingFactorBI, etc., or RA parameters such as ra-ResponseWindow, ra- OccasionList: etc.,

[0316] Such configuration parameters may be configured by RRC or by broadcast SI signaling. The WTRU may be configured with multiple BFD / FDR monitoring patterns for a given set of BFD resources. A monitoring pattern may be configured with applicable BFD resources, one or more BFR reporting resources or frequencies, and / or applicable NES state(s). A BFD monitoring pattern may be meant to be applied by the WTRU as a relaxation of BFD or as a mean to enforce how often the WTRU measures BFD resources for a given set of BFD resource, without having to change which resources (e.g., SSB or CSI-RS) that are monitored. Herein, the terms BFD / FDR sets and BFD / FDR monitoring patterns may be used interchangeably, including procedures describing switching between sets. Herein, FDR and BFD sets may be used interchangeably.

[0317] In examples, the second FDR set may be configured with the same RS resources as a first set but with a different periodicity, with a different RS of the same cell, and / or with a RS from a different cell. Configuration of BFDR timers and / or counters may be applied differently / independently to a resource set.

[0318] In examples, the whole set of BF detection and / or beam failure recovery configurations may be separate configurations for an NES state. For example, there may be an (e.g., independent) beam failuredetection configuration (including any one of the failure detection resources and beam failure parameters) for an NES state of the cell, and there may be an (e.g., independent) beamFailureRecovery configuration for a cell for an NES state of that cell (e.g., indexed with an NES state).

[0319] In examples, the configuration parameters related to BFD / BFR that are common among the different NES states may be configured in a (e.g., one) parameter set (e.g., beamFailureRecoveryCommon), and there may be a separate set of BF detection / recovery configurations that include (e.g., specific) parameters / values for an NES state. In examples, the beamFailureDetectionTimer may be common for (e.g., all) NES states and thus configured in the common BFD / BFR configuration, while the beamFailurelnstanceMaxCount may be different for an NES state and included separately in the corresponding BFD / BFR configuration for that particular NES state.

[0320] The WTRU may select the BFD / R configuration with 2 or more sets of failure detection sources. One or more BFD sets may be applicable in one or more NES states. The WTRU may assume that a given BFD set is active and / or applicable if a given NES state is active (e.g., cell DTX is active, a given SSB time domain pattern is applicable / active, the cell is SSB-less operation is active, and / or spatial or power domain NES adaptation is applied). For example, the WTRU may monitor BFD set 1 if NES state A is active, BFD set 2 when NES state B is active, and so on. For example, a (e.g., one) BFD set may include of the all possible beams to monitor (e.g., when a NES state is deactivated); a (e.g., another) BFD set may include of a subset of beams to monitor / measure, whereby the subset of beams (e.g., SSBs or CSI-RSs) are the ones that are actually transmitted in the associated NES state.

[0321] The WTRU may determine the BFD configuration, BFD pattern or the BFD resources for the BFD procedure based upon the cell NES state for which it is performing beam failure detection (e.g., NES state may be the active cell DTX state). For example, the WTRU may be configured with separate resources for FDR; one for a normal (e.g., non-NES) state and one for NES state taking into account DTX configuration.

[0322] The WTRU may switch monitoring between BFD sets depending on at least one of the following: the WTRU may switch monitoring between BFD sets based on a reception (or lack thereof) of NES state indication for a given NES state (e.g., a NES state associated with the BFD set).

[0323] The WTRU may switch monitoring between BFD sets based on one or more measurements of a channel condition being above or below a threshold, whereby the measurement is conditioned on the BFD set. For example, the WTRU may switch to BFD set A if RSRP measured on BFD set B is less than, or greater than, a configured threshold. The WTRU may switch to BFD set A if RSRP measured on BFD set B excluding resources overlapping with set A is less than, or greater than, a configured threshold. In examples, the condition may be met if there is a sudden drop in measured RSRP among samples or a number of RSRP measured samples is a delta below the averaged / filtered RSRP measurement, e.g., if RSRP(n-2) > Th2 and RSRP(n-1) > Th3 && RSRP(n) < Th2. In examples, the condition may be met if therate of increase / decrease of the RSRP is above / below a certain threshold (e.g., a configured percentage value).

[0324] The WTRU may switch monitoring between BFD sets based on measuring one or more sets of SSBs or CSI-RSs above or below a configured threshold. For example, the WTRU may be configured with SSB set A and set B, where periodicity of set A is double that of set B. For example, if RSRP(set A - set B)< threshold, RSRP (set A)> threshold, RSRP (set B)>threshold, and / or RSRP(set A) - RSRP (set B) > threshold, the WTRU may switch to a different BFD set or pattern.

[0325] The WTRU may switch monitoring between BFD sets as a function of the BFD counter. The WTRU may switch to another BFD set or pattern if BFD counter is less than or larger than a configured threshold. For example, the condition may be satisfied if BFD_counter on > Thresholdl , where Thresholdl < BFI_MAX_Count.

[0326] The WTRU may switch monitoring between BFD sets as a function of the BFD timer. The WTRU may switch to another BFD set or pattern if BFD timer is less than or larger than a configured threshold.

[0327] The WTRU may switch monitoring between BFD sets based on determining that an NES state is active (e.g., a NES state associated with the BFD set).

[0328] The WTRU may switch monitoring between BFD sets based on receiving an indication, a signal, or channel associated with an NES state (e.g., a NES state activation indication, an SSB periodicity change indication, activation of SSB-less operation, reception of a SSB or CSI-RS signal associated with a NES state -e.g., a low power or slim SSB-). For example, the WTRU may switch to BFD set A upon activation of a cell DTX configuration, BFD set B upon activation of another cell DTX configuration, or BFD set C upon deactivation of cell DTX / DRX).

[0329] The WTRU may switch monitoring between BFD sets based on receiving a missed NES indication from the gNB or determining that the WTRU has missed an indication about activation of a NES state.

[0330] The WTRU may switch monitoring between BFD sets as a function of a prohibit timer. For example, the WTRU may be configured to use a certain BFD set for a minimum duration before it can switch to using another BFD set. In examples, an (e.g., single) prohibit timer duration value may be configured for (e.g., all) the BFD sets. In examples, the prohibit timer duration value may be specific to a BFD set. In examples, the prohibit timer may be associated with a given NES state. A combination may be envisioned where multiple prohibit timer duration values are configured for a BFD set and different NES states.

[0331] The WTRU may determine to transmit a BF indication. The WTRU may be configured to transmit a UL WUS, RACH, SR, or a MAC CE for requesting appropriate BFD / BFR configuration and an on-demand RS or for indicating a BFR or a pre-BFR indication, e.g., upon determining that the WTRU has missed anNES state activation signaling / indication or from channel measurements on SSBs, CSI-RS, or BFD sets. For example, the WTRU may be configured with NES state for cell x, and it may miss a configured group- common DCI which provides the NES state activation / de-activation.

[0332] The WTRU may transmit the configured SR, a PUSCH (e.g., a MAC-CE), and / or a UL WUS requesting on-demand sweep of failure detection resource RS and recovery beam RSs (e.g., including all the SSBs of or CSI-RS, possibly for a given cell). The WTRU may provide an indication of currently active BF configuration, the assumed NES state, BFI count, and / or associated measurements in such transmission.

[0333] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication if at least one of the following conditions is satisfied, e.g., if:

[0334] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication based on a measurement of a channel condition being above or below a threshold, whereby the measurement is conditioned on the BFD set. For example, the WTRU may switch to BFD set A if RSRP measured on BFD set B is less than, or greater than, a configured threshold. The WTRU may switch to BFD set A if RSRP measured on BFD set B excluding resources overlapping with set A is less than, or greater than, a configured threshold.

[0335] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication based on measuring one or more set of SSBs or CSI-RSs above or below a configured threshold. For example, the WTRU may be configured with SSB set A and set B, where periodicity of set B is integer multiple of the periodicity of set A, e.g., double (2x), triple (3x) or quadruple (4x) that of set A. In examples, the set A and the set B may be interchanged. For example, if RSRP(set A - set B)< RSRP(set B) + threshold , if RSRP(set A - set B)< threshold, RSRP (set A)> threshold, RSRP (set B)>threshold, and / or RSRP(set A) - RSRP (set B) > threshold, the condition may be satisfied.

[0336] Examples described herein may be explained further by making use of FIG. 5. In The FIG. 5, the WTRU may be monitoring SSB with a (e.g., normal) periodicity T1 , and the WTRU may have been provided with the NES configuration for SSB transmission with relaxed (longer) periodicity T2. The network may provide an indication to switch to the relaxed periodicity T2 of SSB, e.g., through group common DCI, and switch to sparser transmission of SSBs after the NES indication, shown as solid black upward arrows. The WTRU may miss the NES indication and expect the SSB reception with a (e.g., normal) periodicity T 1 . The measurements made at the WTRU with periodicity T 1 may include the relaxed transmissions (solid black arrows) and the dash-dot (cyan) arrows where the network has stopped transmitting due to sparserNES periodicity. The measurements made by the WTRU at the dash-dot (cyan) arrows may be noise (e.g., only) measurements.

[0337] In examples, the WTRU may determine a (e.g., potentially) missed NES indication by comparing the measured RSRP values over the (e.g., normal) SSB occasions (period T1) and NES SSBs (period T2). In the example of FIG. 5, as relaxed SSB periodicity is integer multiple of (e.g., normal) SSB periodicity, the RSRP comparison may be made (e.g., need to be made) over the measurements of transmitted NES occasions (solid black arrows with periodicity T2) versus not-transmitted occasions (T 1 occasions which are not overlapping with T2 occasions). One example can be to use the condition RSRP(set A - set B)< RSRP(set B) + threshold. In the condition, set A - set B means the measurement occasions with periodicity T1 not overlapping with periodicity T2, e.g., dash-dot cyan-blue arrows where the network has stopped transmitting SSBs, and set B are the black arrows after NW employing relaxed SSB transmissions. If the WTRU measures that (set A - set B) has measurements worse than set B measurements by a threshold, it may have an idea of network having switched to an NES state. The number of samples over which the WTRU will measure and compare such conditions may be part of the configuration.

[0338] In examples, the condition may be met if there is a sudden drop in measured RSRP among samples or a number of RSRP measured samples is a delta below the averaged / filtered RSRP measurement, e.g., if RSRP(n-2) > Th2 and RSRP(n-1) > Th3 && RSRP(n) < Th2.

[0339] In examples, the conditions may be specified if the WTRU measurements over NES resources or failure detection resources show a periodic behavior, e.g., one good measurement and one poor measurement, which may be the case if the network switches to 2x (double) relaxed periodicity of SSB / FDR transmissions. Conditions may be defined corresponding to the other relaxation factors.

[0340] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication as a function of the BFD counter. The WTRU may consider the condition satisfied if BFD counter is less than or larger than a configured threshold. For example, the condition may be satisfied if BFD_counter > Thresholdl , where Thresholdl < BFI_MAX_Count.

[0341] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication as a function of the BFD timer. The WTRU may consider the condition satisfied if BFD timer is less than or larger than a configured threshold.

[0342] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication based on a determination that a NES state is active (e.g., a NES state associated with the BFD set).

[0343] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication based on a determination that the WTRU has missed an indication about activation of a NES state.

[0344] The WTRU may transmit a beam failure indication, an anticipated beam failure indication, a beam failure recovery request, or a pre-BFR indication based on a prohibit timer not running. For example, the WTRU may be configured to not send a subsequent BF indication for a minimum configured prohibit time duration after sending a BF indication. In examples, the prohibit timer duration value may be specific / unique to a BFD set. In examples, the prohibit timer may be associated with a given NES state. In examples, the prohibit timer may be associated with a metric associated with the severity of the BF (e.g., on how low the RSRP on the concerned BFD set was, in absolute terms or as compared to other BFD sets; on the RSRP of alternative BFD sets, etc.,).

[0345] Conditions may be defined based on a WUS, SR, or pre-BFR indication that has not been transmitted already. For example, if the WTRU sends the request, and the NW provides the same NES state known to the WTRU, the WTRU may not transmit the request at least for a duration of time.

[0346] Conditions may be defined based on a WUS, SR, or pre-BFR indication that has been transmitted already, and the WTRU has not received a reply from the network yet (e.g., a DL signal, indication or message).

[0347] The WTRU may be associated with a behavior upon transmitting a pre-BFR indication, determining a BF, or a pre-BF event. Upon transmitting the WUS, SR, or pre-BFR indication, or upon satisfying at least one of the above conditions (e.g., for BFD switching), the WTRU may suspend the BFD counter, restart the BFD timer, start a prohibit timer, and / or suspend the BFD timer. The WTRU may suspend the counter for a predefined or configured period of time and resume the counting using the applicable BFD set. The indication transmitted by the WTRU may include an enquiry about the active NES state.

[0348] The WTRU may resume the BFD counter, resume the BFD timer, and / or restart the BFD timer upon reception of DL signal or channel from the network, which may be: a full SSB, CSI-RS, CSI-RS from a given BFD set (e.g., one associated with the (e.g., normal) set or the NES state set), reception of PDCCH, PDSCH, a MAC CE, or upon reception of an indication of a change of the NES state (e.g., a DCI indicating deactivation of cell DTX). This may be made (e.g., only) after transmitting WUS, SR, or pre-BFR indication by the WTRU.

[0349] In examples, the WTRU may resume a suspended BFD counter, resume a suspended BFD timer, and / or restart the BFD timer, after reception of a SSB or CSI-RS signal, e.g., associated with a given BFD set. The WTRU may suspend the BF detection timer and BF_counter until the next full SSB (CSI-RS) occasion or NW indication on BF configuration switching. For example, the WTRU may suspend thecounter until the reception of CSI-RS or SSB sample associated with the NES BFD set. The WTRU may determine to (e.g., only) count BFD instances associated with the NES BFD set, e.g., if the counter was suspended, a pre-BFI signal was transmitted by the WTRU, or if at least one condition for BFD set switching as described herein is satisfied.

[0350] The WTRU may receive a network indication for an appropriate NES / BF configuration. After the WUS, SR, or pre-BFR indication transmission, the WTRU may monitor a response from the network (e.g., a PDCCH, PDSCH, SSB, CSI-RS, and / or a DL signal). In response, the WTRU may monitor for reception of a full SSB, CSI-RS from a different BFD set, or CSI-RS from the set of recovery beams.

[0351] In examples, the WTRU may receive an indication of the active NES state. The active NES state may include the active NES state of the cell x for which WTRU provided anticipated beam failure indication, NES state for other serving cells, NES state of recovery resources etc. In response, the WTRU may receive a missed NES state (de)-activation indication from the gNB. A missed NES indication may further indicate a sweep timing / details for the transmission of FDR and recovery beams, e.g., on-demand SSBs, and / or the active NES state, e.g., active RS / SSB periodicity. For example, after transmission of WUS, SR, or pre-BFR indication, the WTRU may start to monitor the activated RS / SSB according to the active set associated to the active NES mode or normal mode.

[0352] The WTRU may apply the applicable parameters of the BFD set (e.g., max BFI value, BFD timer value, BFD resources, BFR resources, and / or recovery beams) assorted with the signaled / determined NES state upon reception of the active NES state. The WTRU may apply the applicable parameters of the BFD set (e.g., max BFI value, BFD timer value, BFD resources, BFR resources, and / or recovery beams) upon receiving a CSI-RS or SSB associated with an BFD set.

[0353] The WTRU may transmit a beam failure recovery MAC CE comprising of the measurements made on the recovery beams, e.g., upon receiving the response with a full SSB or if BFD_counter >= BFI _MAX_Count, e.g., through RACH if BF is detected on the Spcell, or through the Spcell if BF is detected on an Scell.

[0354] In examples, when DCI was missed and WTRU was on (e.g., normal) FDR, the WTRU may monitor for the active NES state and / or a sweep of FDR resources (e.g., a full SSB) upon transmitting a WTRU indication. The WTRU may suspend BFD counters and / or timers until receiving a sweep of FDR resources or an indication of the active NES state (or the active / associated BFD set). The WTRU indication / request may involve a request for failure detection resources and / or recovery beams.

[0355] In examples, a missed DCI of cell DTX may lead to WTRU performing measurements per a (e.g., normal) non NES state FDR resources (non-DTx case). The WTRU may receive a NES state indication from the NW (e.g., a retransmission of a GC-DCI indicating the active NES state), whereby the indicationmay further include a command indicating to the WTRU to apply different BFD set and / or BFD timer / counter values.

[0356] A beam failure configuration may be associated with switching for NES. FIG. 5 illustrates a WTRU anticipated BF indication upon missing an SSB adaptation (NES) indication.

[0357] In examples, the network may be adapting FDRs based upon NES indication. The WTRU may continue monitoring the non-NES FDR. The WTRU may provide a pre-BF indication to the NW based upon the measurements made on non-NES FDR and if RSRP(FDR_set1_Excluded_FDR_set2) < RSRP(FDR_set2). In response, the NW may provide an indication of an actual NES state of one or more cells. The WTRU may start monitoring NES FDR set for Beam failure procedure.

[0358] An NES based indication may provide the WTRU one or more of the following: current NES state, target NES state, FDR, updated FDR, FDR configurations, recovery beams, recovery beams configurations, etc. The network may transmit an NES based indication through signaling mechanisms, e.g., WTRU dedicated, group common, or broadcast signaling. The WTRU may not be able to decode the NES indication, for example, due to poor reception, timing or other constraints. A missed NES indication may lead the WTRU to be a-sync with the NW NES state, e.g., the WTRU may not know the latest NES state of the cell and may apply (e.g., different) NES state assumptions based upon its known (e.g., previous) NES state.

[0359] The WTRU may be configured with the following. The WTRU may be configured with a 1 st / 2nd set of failure detection resources and BF detection timers / counters for beam failure detection in a (e.g., normal) mode / NES mode. The WTRU may be configured with a set of recovery beams for beam failure recovery where the recovery beams may be applying NES in time domain (time / spatial / power domain). The WTRU may be configured with An UL SR configuration requesting appropriate BFD / BFR configuration and on-demand RS. The WTRU may measure RSRP over the (e.g., normal) FDR and over the NES FDR.

[0360] If any of the following conditions is met: (i) RSRP (Set1_Excl_Set2) < RSRP (Set 2) + Th4, (ii) BFD_counter > Thresholdl (where Threshold 1 < BFI_MAX_Count), the WTRU may transmits the configured SR [MAC-CE or UL WUS] on the SpCell requesting on-demand sweep of “failure detection resource RS” and recovery beam RSs (e.g., including (e.g., all) the SSBs of the SpCell or CSI-RS). The WTRU may provide an indication of currently active BF configuration or the assumed NES state.

[0361] The WTRU may switch to a second BF configuration [BFD_Timers, BFI_Max_Count] and a second set of failure detection resources upon receiving a (missed) NES indication from the gNB. A (missed) NES indication may indicate one or more of the following: a sweep timing / details for the transmission of FDR and recovery beams, e.g., on-demand SSBs; or the active NES state, e.g., active RS / SSB periodicity

[0362] The WTRU may start to monitor the activated RS / SSB according to the active set associated to the active NES mode or normal mode. The WTRU may transmit beam failure recovery MAC CE comprising the measurements made on the recovery beams if BFD_counter >= BFI_MAX_Count, through RACH if BF is detected on the Spcell, or through the Spcell if BF is detected on an Scell.

[0363] Beam failure detection / recovery may be associated with measurement resources undergoing NES. A WTRU may be configured with failure detection sources and recovery beams with NES. To detect beam failure over a serving cell x, a WTRU may be configured with one or more sets of failure detection resources. A WTRU may be configured with a set of recovery beams and associated parameters such as RACH parameters (occasions, preamble sequences, etc.) to recover in case it detects a beam failure.

[0364] A WTRU may be configured to adjust or compensate its measurements used for beam failure detection when the cell x is applying a (e.g., some) form of NES technique. For example, the WTRU may be configured with a power compensation factor to be applied when the cell x is applying NES in power domain, or configured with a spatial compensation factor when the cell x is applying NES in spatial domain. The WTRU may be configured to generate BFI differently when the cell x is applying NES technique. A (e.g., different) generation of BFI may be in terms of applying different RSRP thresholds to measurements, or changing the periodicity of BFI generation according to the NES parameters, e.g., cell DTx parameters, including periodicity and / or active time and / or inactive time etc.

[0365] A WTRU may be (pre-)specified the adjustment or compensation factors to be applied to different measurements. The WTRU may apply the adjustments or compensation factors to measurement signals when the cell is applying a one of the NES techniques to the relevant FDRs or recovery resources.

[0366] A WTRU PHY layer generation may be associated with a beam failure instance. The PHY layer at the WTRU may generate a BF instance if the following condition is met: compensated meas for (e.g., all) failure detection resources < Q_out_LR. Where Q_out_LR is a threshold applied to L1 RSRP measurements of failure detection resources, and compensated Meas for i-th RS is computed through the following: Compensated_Meas_RSJ = Meas_RSJ + NES_offset_RSJ, where compensation for i-th RS, NES_offset_RSJ is determined by the WTRU as any of the following. The NW may provide an offset for every RS that it configures as FDR, e.g., NES_offset_RSJ for i-th RS. The NW may configure the offsets to the WTRU.

[0367] The WTRU may be provided offsets or compensation factors to be applied to the PHY layer measurements of different RSs. Adjustments or compensation factors may be pre-specified, and the WTRU may apply the to the measurements when it knows that the NW is applying a NES technique to FDRs. The network may configure the adjustment or compensation factors to the WTRU. The network may configure the adjustment / compensation factors to the WTRU as part of the beam / link detection / recovery configuration or as part of the NES configuration. The configuration for the factors may be explicit orimplicit. In implicit design, for example, the WTRU may determine through NES configuration the offset that it will measure due to the NES technique in use and will apply the same offset to compensate the measurement. The network may specify an additional offset to be applied in addition to the compensation factors.

[0368] The WTRU may be specified or configured with NES_offset_PD, NES_offset_SD, and NES_offset_DTx, with their activation status for power domain, spatial domain or time domain compensation respectively.The WTRU may be specified or configured with NES_offset_PD, NES_offset_SD, and NES_offset_DTx, with their activation status, and WTRU may determine the NES_offset combined over active NES techniques.

[0369] NES_offset_i = PD_Active*(NES_offset_PD) + SD_Active*(NES_offset_SD) + DTx_Active*(NES_offset_DTx). XX_Active are binary flags indicating if the current measurements gets impacted by NES or not.

[0370] A WTRU may perform BFD with BFI generated from compensated measurements. A WTRU may be configured to count BFIs at the MAC layer generated for a cell x and detect beam failure for cell x when BFD_Counter reaches a configured threshold BFD_MAX_Count and BFIs are generated over the compensated measurements of FDRs as provided earlier.

[0371] A WTRU may measure the recovery beams. A WTRU may start monitoring the recovery beams to recover from beam failure for cell x. The WTRU may monitor the recovery beams with the (e.g., normal) periodicity of the recovery beams. The WTRU may be provided with an indication that the recovery beams or candidate beams are undergoing one of the NES techniques. In examples, the WTRU may know through cell configuration or cell signaling that the NW is applying NES techniques, and that may have an impact on the transmission and measurement of candidate beams for recovery.

[0372] If a WTRU knows that the recovery candidate beams are applying one of the NES techniques, the WTRU may apply NES compensation to the measurements of recovery beams. The WTRU may determine the adjustment or compensation to be applied to the candidate recovery beams measurements according to one of the following. Adjustments or compensation factors may be pre-specified, and the WTRU may apply the measurements when it knows that the NW is applying NES technique to the recovery beams.

[0373] The network may configure the adjustment or compensation factors to the WTRU. The network may configure the adjustment / compensation factors to the WTRU as part of the recovery configuration or as part of the NES configuration. The configuration for the factors may be explicit or implicit. In implicit design, for example, the WTRU may determine through NES configuration the offset that it will measuredue to the NES technique in use and may apply the same offset to compensate the measurement. The network may specify an additional offset to be applied in addition to the compensation.

[0374] Examples described herein for compensating the measurements made over failure detection resources when the NW is applying one of the NES techniques may be applied to the measurements of the candidate recovery resources. The network may provide similar NES parameters / offsets for different candidate recovery beams for the WTRU to apply when the beams are known at the WTRU to be in NES state, e.g., through a network indication / configuration.

[0375] A WTRU may select a suitable recovery resource beam. A WTRU may select a suitable recovery resource / beam among the recovery resources / beams it monitors. If the network has configured the WTRU to apply NES adjustments / compensation to the measurements over the recovery beams, the WTRU selection of recovery beams may be made based upon the compensated measurements. The WTRU may select the recovery beam with the highest measured RSRP. In examples, the WTRU may be configured to perform filtering over more than one measured values prior to selection. For example, the WTRU may average a given number of values. In examples, different filtering coefficients / weights may be specified to be used by the WTRU. In examples, the WTRU may be configured to prioritize a resource or a set of resources. For example, the WTRU may be configured to apply an offset to the measured values to (de- )prioritize a (e.g., set of) resources. In examples, a WTRU may be configured to prioritize one set of resources over another set of resources. For example, the WTRU may be configured to prioritize non-NES candidate beams over NES candidate beams.

[0376] A WTRU may transmit a UL indication. After monitoring the resources relevant for beam failure detection and recovery, a WTRU may determine to transmit a UL indication. The resource relevant for beam failure detection may be the failure detection resources that the WTRU monitors to detect beam failure, candidate recovery beams, on-demand failure detection resources, on-demand recovery resources, SSB beams, or CSI-RS beams.

[0377] A WTRU may determine to transmit a beam failure indication to the network for cell x if the WTRU has detected beam failure for cell x according to the configured criteria. The WTRU may provide the selected recovery resource reference as part of the beam failure indication.

[0378] The UL indication may be transmitted as PHY, MAC or RRC signaling. In examples, a WTRU may transmit RACH on the same cell where it detects beam failure (e.g., , if the cell is the primary cell of its cell group). The WTRU may determine a RACH occasion and other parameters for the transmission of a RACH preamble according to its selected recovery / candidate beam.

[0379] In examples, a WTRU may transmit a beam failure indication as MAC CE over the primary cell of a cell group comprising of cell x where the WTRU has detected beam failure for cell x (e.g., cell x is not the primary cell of the cell group for the WTRU).

[0380] Although features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without other features and elements.

[0381] Although the implementations described herein may consider 3GPP specific protocols, it is understood that the implementations described herein are not restricted to this scenario and may be applicable to other wireless systems. For example, although the solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it is understood that the solutions described herein are not restricted to this scenario and are applicable to other wireless systems as well. For example, while the system has been described with reference to a 3GPP, 5G, and / or NR network layer, the envisioned embodiments extend beyond implementations using a particular network layer technology. Likewise, the potential implementations extend to all types of service layer architectures, systems, and embodiments. The techniques described herein may be applied independently and / or used in combination with other resource configuration techniques.

[0382] The processes described herein may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted over wired and / or wireless connections) and / or computer-readable storage media. Examples of computer- readable storage media include, but are not limited to, a read-only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as, but not limited to, internal hard disks and removable disks, magneto-optical media, and / or optical media such as compact disc (CD)-ROM disks, and / or digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and / or any host computer.

[0383] It is understood that the entities performing the processes described herein may be logical entities that may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of, and executing on a processor of, a mobile device, network node or computer system. That is, the processes may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of a mobile device and / or network node, such as the node or computer system, which computer-executable instructions, when executed by a processor of the node, perform the processes discussed. It is also understood that any transmitting and receiving processes illustrated in figures may be performed by communication circuitry of the node under control of the processor of the node and the computer-executable instructions (e.g., software) that it executes.

[0384] The various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the implementations and apparatus of the subject matter described herein, or certain aspects or portions thereof, may take the form of program code (e.g., instructions) embodied in tangible media including any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the subject matter described herein. In the case where program code is stored on media, it may be the case that the program code in question is stored on one or more media that collectively perform the actions in question, which is to say that the one or more media taken together include code to perform the actions, but that - in the case where there is more than one single medium - there is no requirement that any particular part of the code be stored on any particular medium. In the case of program code execution on programmable devices, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs that may implement or utilize the processes described in connection with the subject matter described herein, e.g., through the use of an API, reusable controls, or the like. Such programs are preferably implemented in a high level procedural or object-oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language and combined with hardware implementations.

[0385] Although example embodiments may refer to utilizing aspects of the subject matter described herein in the context of one or more stand-alone computing systems, the subject matter described herein is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the subject matter described herein may be implemented in or across a plurality of processing chips or devices, and storage may similarly be affected across a plurality of devices. Such devices may include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems such as automobiles and airplanes.

[0386] In describing the preferred embodiments of the subject matter of the present disclosure, as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

Claims

CLAIMSWhat is claimed is:1 . A wireless transmit / receive unit (WTRU) comprising: a processor configured to: receive configuration information associated with a first cell, wherein the configuration information comprises an uplink indication configuration to provide a pre-beam failure indication; determine that a beam failure detection counter value exceeds a first threshold and is less than a second threshold, wherein the second threshold is associated with beam failure detection; transmit to a network node, based on the determination that the beam failure detection counter value exceeds the first threshold and is less than the second threshold, a pre-beam failure indication; receive, from the network node, an indication associated with network transmissions, wherein the network transmissions comprise one or more of: a sweep of a plurality of on-demand synchronization signal block (SSB) transmissions, a plurality of recovery beams, or failure detection resources (FDRs); and measure a plurality of reference signals (RSs) associated with the network transmissions; send, to the network node, a transmission based on the measurements of the plurality of RSs.

2. The WTRU of claim 1 , wherein the transmission comprises an indication that indicates that an on- demand sweep is no longer needed.

3. The WTRU of claim 2, wherein the processor is further configured to determine that the on- demand sweep is no longer needed based on a determination that the measurements of the plurality of RSs or on-demand SSB transmissions satisfy a third threshold.

4. The WTRU of claim 1 , wherein the processor is further configured to select a recovery beam based on the measurements of the plurality of RSs.

5. The WTRU of claim 4, wherein the selected recovery beam is associated with a measurement of an RS being greater than or equal to a fourth threshold, wherein the RS is one of the plurality of RSs.

6. The WTRU of claim 4, wherein the transmission comprises an indication of the selected recovery beam.

7. The WTRU of claim 1 , wherein the transmission is sent based on the beam failure detection counter value exceeding the second threshold.

8. The WTRU of claim 1 , wherein the network transmissions further comprise one or more of: a plurality of identifiers of a plurality of candidate recovery beams to be transmitted; a time duration within which the plurality of candidate recovery beams will be transmitted; a plurality of time and frequency parameters associated with the transmission of the recovery beams; an indication of a bandwidth part (BWP) to be used; or an indication indicating that the WTRU is to transmit an indication based on recovery beams no longer being needed.

9. The WTRU of claim 1 , wherein the configuration information further comprises one or more of a set of failure detection resources (FDRs) for beam failure detection or a set of recovery beams for beam failure recovery.

10. A method for a wireless transmit / receive unit (WTRU), the method comprising: receiving configuration information associated with a first cell, wherein the configuration information comprises an uplink indication configuration to provide a pre-beam failure indication; determining that a beam failure detection counter value exceeds a first threshold and is less than a second threshold, wherein the second threshold is associated with beam failure detection; transmitting to a network node, based on the determination that the beam failure detection counter value exceeds the first threshold and is less than the second threshold, a pre-beam failure indication; receiving, from the network node, an indication associated with network transmissions, wherein the network transmissions comprise one or more of: a sweep of a plurality of on-demand synchronization signal block (SSB) transmissions, a plurality of recovery beams, or failure detection resources (FDRs); measuring a plurality of reference signals (RSs) associated with the network transmissions; and sending, to the network node, a transmission based on the measurements of the plurality of RSs.11 . The method of claim 10, wherein the transmission comprises an indication that indicates that an on-demand sweep is no longer needed.

12. The method of claim 11 , wherein the method further comprises determining that the on-demand sweep is no longer needed based on a determination that the measurements of the plurality of RSs or on- demand SSB transmissions satisfy a third threshold.

13. The method of claim 10, wherein the method further comprises selecting a recovery beam based on the measurements of the plurality of RSs.

14. The method of claim 13, wherein the selected recovery beam is associated with a measurement of an RS being greater than or equal to a fourth threshold, and wherein the RS is one of the plurality of RSs.

15. The method of claim 13, wherein the transmission comprises an indication of the selected recovery beam.

16. The method of claim 10, wherein the transmission is sent based on the beam failure detection counter value exceeding the second threshold.

17. The method of claim 10, wherein the network transmissions further comprise one or more of: a plurality of identifiers of a plurality of candidate recovery beams to be transmitted; a time duration within which the plurality of candidate recovery beams will be transmitted; a plurality of time and frequency parameters associated with the transmission of the recovery beams; an indication of a bandwidth part (BWP) to be used; or an indication indicating that the WTRU is to transmit an indication based on recovery beams no longer being needed.

18. The method of claim 10, wherein the configuration information further comprises one or more of a set of failure detection resources (FDRs) for beam failure detection or a set of recovery beams for beam failure recovery.

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