Multi-cell random access in energy saving networks

Abstract

Systems, methods, and instrumentalities are described herein related to multi-cell random access with on-demand synchronization signal block (SSB). A wireless transmit / receive unit (WTRU) may receive a pre-synchronization (pre-sync) signal. The WTRU may determine a first cell transmitting the pre-sync signal and a transmitting beam index associated with the pre-sync signal based on a property of the pre-sync signal. The WTRU may determine whether a condition is satisfied. If the condition is satisfied, the WTRU may receive a transmission from a second cell. The WTRU may determine a random access channel (RACH) configuration for the first cell based on the transmission from the second cell and the pre-sync signal. The WTRU may determine an RO that is associated with the first cell and a preamble based on the pre-sync signal and the RACH configuration for the first cell. The WTRU may transmit the preamble on the determined RO.

Description

MULTI-CELL RANDOM ACCESS IN ENERGY SAVING NETWORKSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 531,089, filed August ?, 2023 the contents of which is incorporated by reference herein.BACKGROUND

[0001] Mobile communications using wireless communication continue to evolve. A fifth generation may be referred to as 5G. A previous (legacy) generation of mobile communication may be, for example, fourth generation (4G) long term evolution (LTE).SUMMARY

[0002] Systems, methods, and instrumentalities are described herein related to system access in energy saving networks. A device, such as a wireless transmit / receive unit (WTRU) may perform (e.g., be configured to perform) one or more of the following actions.

[0003] A WTRU may receive a pre-synchronization (pre-sync) signal. The pre-sync signal may be, or may include, at least one of: a discovery signal, a synchronization signal block (SSB), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), or a combination of PSS and an SSS. The SSB signal associated with the pre-sync signal may not be a full SSB signal.

[0004] The WTRU may determine a cell (e.g., a first cell) transmitting the pre-sync signal / or and a transmitting beam index (e.g., a beam index and / or a transmitting beam) associated with the pre-sync signal based on a property of the pre-sync signal, the property associated with the pre-sync signal comprises at least one of a time, a frequency, a sequence selection, a phase, a sequence identification (ID) associated with the pre-sync signal.

[0005] The WTRU may determine whether a condition is satisfied. The condition may be satisfied based on at least one of a determination that a received power associated with the pre-sync signal is greater than a threshold, a determination that a full SSB is not received from the first cell, or a determination the first cell is in an energy savings state.

[0006] Based on a determination that the condition is satisfied, the WTRU may receive a transmission from a second cell. The transmission from the second cell may be, or may include, at least one of an SSB or a system information block (SIB).

[0007] The transmission may be associated with at least one SSB from the second cell. For example, the WTRU may determine (e.g., further determine) to receive the at least one SSB from the second cell (e.g., via the second cell) to receive at least one SSB based on at least one of a same frequency that the pre-sync signal is detected (e.g., received), a different frequency that the pre-sync signal is detected (e.g., received), an indication associated with the pre-sync signal, or a parameter including at least one of a time resource to receive (e.g., detect) the at least one SSB, a frequency resource to receive (e.g., detect) the at least one SSB, a carrier frequency associated with the at least one SSB, or a cell ID associated with the at least one SSB.

[0008] The WTRU may determine a random access channel (RACH) configuration for the first cell based on the transmission from the second cell and the pre-sync signal. The RACH configuration may be, or may include, an association of the pre-sync signal to at least one physical RACH occasion (RO) associated with the first cell. The pre-sync signal may be associated with the first cell. The RACH configuration may be (e.g., may further be), or may include (e.g., may further include), at least one of: a system timing associated with the first cell and a first cell ID, an association of a transmitting beam (Tx beam) to the physical RO associated with the first cell, or a partition of RACH preambles with the RO or the TX beam associated with accessing the first cell.

[0009] The WTRU may determine an RO that is associated with the first cell and a preamble based on the pre-sync signal and / or the RACH configuration for the first cell.

[0010] The WTRU may transmit the preamble on the RO that is associated with the first cell.

[0011] The WTRU may monitor for a random access response (RAR) from the first cell. For example, the WTRU may monitor an RAR from the first cell during an RAR window. The WTRU determine whether the RAR is received. Based on a determination that the RAR is received, the WTRU may determine a resource to transmit a message. The WTRU may transmit the message on the resource.

[0012] In examples, based on a determination that the RAR is not received on the first cell, the WTRU may determine that at least one SSB is received from the first cell. Based on the determination that the at least one SSB is received from the first cell, the WTRU may transmit a preamble (e.g., a second preamble) on the RO that is associated with the first cell. The RO used for the second preamble transmission may be based on (e.g., further based on) a measured SSB associated with the first cell.

[0013] In examples, based on a determination that the RAR is not received on the first cell, the WTRU may determine whether a number of retransmissions of the preamble is above a threshold. If the number of retransmissions of the preamble is above the threshold, the WTRU may transmit the preamble on the second cell.

[0014] In examples, the WTRU may determine whether a fallback indication is received in the RAR on the first cell. If the fallback indication is received in the RAR, the WTRU may perform a RACH procedure on the second cell.

[0015] In examples, the WTRU may determine that a reference signal receive power (RSRP) associated with the second cell. For example, the WTRU may determine that an RSRP associated with the second cell is below a threshold (e.g., a second threshold). If the RSRP is below the threshold (e.g., the second threshold), the WTRU may perform a RACH transmission on the first cell.

[0016] In examples, a WTRU may detect (e.g., receive) a pre-sync signal from a network energy savings (NES) cell and a SSB / SIB (e.g., SIB-1) from a second cell. The WTRU may, e.g., based on the detection (e.g., and / or reception), determine a RACH configuration of the first cell from the SSB / SIB (e.g., SIB-1) on the second cell. The WTRU may perform a random access by performing a first preamble transmission to the first cell, receiving an (e.g., on-demand) SSB from the first cell, and re-transmitting a physical random access channel (PRACH) preamble, e.g., based upon the received SSB from the first cell.

[0017] A WTRU may perform monitoring of an (e.g., a configured) NES cell’s pre-sync signal(s), for example, if / when the WTRU receives beam failure instances for the current beam. The WTRU may report detected pre-sync signals and IDs to the cell it is connected to, for example, if the detected pre-sync signals are better than a first threshold and the current beam RSRP falls below a second threshold The WTRU may (e.g., be configured to) perform a RACH on a (e.g., one of the) suitable NES-detected cell.

[0018] Systems, Methods, and instrumentalities are described herein related to multi-cell random access with on-demand SSB. A device may (e.g., be configured to) do one or more of the following actions. A WTRU may detect (e.g., receive) a pre-sync from a first cell (e.g., an NES first cell) and a SSB from a second cell (e.g., a macro cell). The WTRU may, e.g., based on the detection, determine a RACH configuration of the first cell from the SSB / SIB (e.g., SIB-1) on the second cell. The WTRU may perform random access using both cells, for example, by performing a first preamble transmission with a sub- optimal quasi-colocation (QCL) assumption regarding the first cell. The WTRU may receive an (e.g., on- demand) SSB. The WTRU may re-transmit a PRACH preamble, for example, based upon the on-demand SSB. The WTRU may fall back to the second cell, for example, if an RAR is not received.

[0019] A WTRU may detect (e.g., receive) a pre-sync (e.g., discovery) signal, such as a PSS plus an SSS (e.g., with some modification), from a first (e.g., small) cell. The WTRU may identify the first cell and a transmission beam (Tx-Beam) transmitting the pre-sync signal through one or more of the physical properties of the signal (e.g., time, frequency, sequence selection, phase, sequence ID, etc.). The WTRU may receive and decode an SSB / SIB-1 from a second (e.g., macro) cell, for example, if at least one of the following is met: the pre-sync received power from the first cell is greater than a first threshold (e.g., pre- sync-ReceivedPower from 1 cell > Threshol d 1 ); a full SSB is not received from the first cell or the first cell is determined to be in an NES state; and / or an RSRP from the second cell is less than a second threshold (e.g., Threshold 2). The WTRU may determine the PRACH configuration for the first cell, for example, based upon the received SIB-1 of the second cell and a detected pre-sync sequence of the first cell, which may include, for example, one or more of the following: the system timing of the first cell, and the cell ID; association of the first cell Tx-Beam to RACH occasions (ROs) of the first cell; partition of RACH preambles associated with accessing the first cell; and / or association of first cell SSBs to first cell ROs, e.g., for preamble re-transmission on the first cell. The WTRU may determine the RO / preamble to use on the first cell, for example, based on the pre-sync signal of the first cell, and / or the (e.g., configured) association between pre-sync and ROs received on the second cell. The WTRU may perform a RACH procedure (e.g., 2-step or 4-step) on the first cell, e.g., using / with the determined parameters. The WTRU may monitor the random access (RA) response on the first cell. The WTRU may monitor for SSB reception from the first cell, e.g., while the RAR window is running. The WTRU may transmit another preamble to the first cell, for example, if an RAR is not received on the first cell and the WTRU receives one or more SSBs from the first cell. The WTRU may determine the RO to use for the preamble transmission on the first cell, for example, based on a (e.g., the best) measured SSB on the first cell. The WTRU may transmit a preamble on the second cell, for example, if an RAR is not received on the first cell, e.g., after N attempts (e.g., N>=1). The WTRU may continue the RACH procedure on the second cell (e.g., by transmitting MSG3 using the grant indicated in the RAR payload or by re-transmitting the preamble on the second cell), for example, if the WTRU receives a fallback indication in an RAR from the first cell (e.g., backoff indicator or a bit in the RAR payload.

[0020] An example device may include a processor configured to perform one or more actions. For example, a device may detect (e.g., receive) a pre-sync signal. The device may identify a first cell transmitting the pre-sync signal based on at least one property associated with the pre-sync signal. The device may receive an SSB or an SIB from a second cell. The device may determine a RACH configuration for the first cell based on the SSB or SIB from the second cell and the pre-sync signal. The device may perform a RACH procedure on the first cell using the RACH configuration. The device may receive an SSBfrom the first cell. The device may determine a second RACH configuration for the first cell based on the SSB from the first cell. The device may perform a second RACH procedure on the first cell using the second RACH configuration. The device may perform a third RACH procedure on the second cell if a random access response is not received from the first cell or if a fallback indication is received from the first cell.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0022] 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;

[0023] FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1 A according to an embodiment;

[0024] FIG. 1 D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0025] FIG. 2 illustrates an example of a time-frequency structure of a synchronization signal block (SSB).

[0026] FIG. 3 illustrates an example of SSB beam sweeping within SSB burst sets.

[0027] FIG. 4 illustrates an example flow diagram of a WTRU performing multi-cell random access with an on-demand synchronization signal block (SSB).EXAMPLE NETWORKS FOR IMPLEMENTATION OF THE EMBODIMENTS

[0028] 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 UWDTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0029] 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 telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or a “ST A”, may be configured to transmit and / or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0030] 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.

[0031] 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 bedivided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0032] 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).

[0033] 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 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0034] 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).

[0035] 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).

[0036] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., an eNB and a gNB).

[0037] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., WorldwideInteroperability 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.

[0038] 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. 1 A, 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.

[0039] 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.

[0040] 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 wiredand / 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 willbe appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0045] Although the transmit / receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0046] 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.

[0047] 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).

[0048] 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.

[0049] 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 determineits 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.

[0050] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and / or Augmented Reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0051] 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)).

[0052] 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.

[0053] 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.

[0054] 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.

[0055] The CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0056] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In representative embodiments, the other network 112 may be a WLAN.

[0062] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic in to and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and / or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source 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 (I BSS) 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.

[0063] 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.

[0064] 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.

[0065] 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 MHzchannels. 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).

[0066] 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).

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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 to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0071] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0072] 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, 160csubstantially 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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 UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernetbased, and the like.

[0077] 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 184a, 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.

[0078] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0079] 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.

[0080] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and / or may performing testing using over-the-air wireless communications.

[0081] 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.

[0082] Systems, methods, and instrumentalities are described herein related to system access in energy saving networks.

[0083] A wireless transmit / receive unit (WTRU) may detect (e.g., receive) a pre-synchronization (presync) from a first cell (e.g., a network energy savings (NES) cell) and a synchronization signal block (SSB)Zsystem information block (SIB) (e.g., SIB-1) from a second cell. The WTRU may, e.g., based on the detection and / or the reception, determine a random access channel (RACH) configuration of the first cell from the SSB / SIB (e.g., SIB-1) on the second cell. The WTRU may perform a random access by performing a first preamble transmission to the first cell, receiving an (e.g., on-demand) SSB from the first cell and re-transmitting a physical random access channel (PRACH) preamble, e.g., based upon the received SSB from the first cell.

[0084] A WTRU may perform monitoring of an (e.g., a configured) NES cell’s pre-sync signal(s), for example, if / when the WTRU receives beam failure instances for the current beam. The WTRU may report detected / received pre-sync signals and IDs to the cell that the WTRU is connected to, for example, if the detected / received pre-sync signals are better than a first threshold and the current beam reference signal received power (RSRP) falls below a second threshold. The WTRU may (e.g., be configured to) perform a RACH on a (e.g., one) suitable NES-detected cell.

[0085] A network (e.g., 3GPP RAN) may (e.g., enable the network to) minimize its power consumption from transmission and reception. Such minimization may be beneficial for reducing operational costs and environmental sustainability.

[0086] A network may improve efficiency, for example, by minimizing transmissions from the network if there is no data. For example, an always-on cell-specific reference signal (CRS) may not be used (e.g., in NR). There may be further energy consumption reduction.

[0087] For example, a network may still consume energy if / when not transmitting from other activities, such as baseband (e.g., digital) processing for reception or beamforming. Such idle power consumption may not be negligible in dense networks, even if / when no WTRU is served during a given period. Energyconsumption may be reduced, for example, if the network could turn off these activities when not transmitting to a WTRU.

[0088] A network (e.g., NR, unlike LTE) may not require transmission of an always-on synch or reference signals and / or may support adaptable bandwidth and multiple input multiple output (MIMO) capabilities. This adaptation of network resources may enable greater efficiency in operating newer deployments and / or later generations.

[0089] 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 signal to interference plus noise ratio (SI NR)), a channel state indicator reference signal (CSI-RS) resource indicator (CRI), a synchronization signal (SS) / PBCH block resource indicator (SSBRI), layer indicator and / or any other 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. CSI components may correspond to at least a CSI-RS resource indicator (CRI), an SSB resource indicator (SSBRI), an indication of a panel used for reception at the WTRU (e.g., 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 / or other channel state information, such as at least a rank indicator (Rl), a channel quality indicator (CQI), a precoding matrix indicator (PMI), a Layer Index, and / or the like.

[0090] Uplink control information (UCI) may include, for example, one or more of the following: CSI, hybrid automatic repeat request (HARQ) feedback for one or more HARQ processes, a scheduling request (SR), a Link recovery request (LRR), configured grant or cell group uplink control information (CG-UCI), and / or other control information bits that may be transmitted on the physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH).

[0091] One or more channel conditions may be one or more (e.g., any) conditions relating to the state of the radio / channel, which may be determined by the WTRU, for example, from one or more of the following: 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), a 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).

[0092] A PRACH resource may be, for example, a PRACH resource (e.g., in frequency), a PRACH 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 (e.g., certain) preamble sequence used for the transmission of a preamble in a random access procedure.

[0093] A property of scheduling information (e.g., an uplink grant or a downlink assignment) may include, for example, at least one of the following: a frequency allocation; an aspect of time allocation, such as a duration; a priority; a modulation and coding scheme (MCS); a transport block size; a number of spatial layers; a number of transport blocks to be carried; a transmission configuration indication (TCI) state or SRS resource indicator (SRI); a number of repetitions; an indication whether the grant is a configured grant type 1 , type 2, or a dynamic grant.

[0094] An indication by downlink control information (DCI), or an indication, may include, for example, at least one of the following: an (e.g., explicit) indication by a DCI field or by RNTI used to mask a cyclic redundancy check (CRC) of the PDCCH. An (e.g., implicit) indication may be provided, for example, by a property, such as DCI format, a DCI size, a CORESET or search space, an aggregation level, an identity of first control channel resource (e.g., index of first CCE) for a DCI, and / or the like. The mapping between the property and the value may be signaled, for example, by an RRC singaling and / or a MAC singaling. An (e.g., explicit) indication may be provided by a DL MAC control element (CE).

[0095] 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 (e.g., determine implicitly) a cell DTX / discontinuous reception (DRX) state, for example, from a determined active availability state and visa-versa.

[0096] Use of “a” and “an” and similar phrases herein are to be interpreted as “one or more’ and “at least one.” Similarly, any term which ends with the suffix “(s)” is to be interpreted as “one or more” and “at least one.” The term “may” is to be interpreted as “may, for example.”

[0097] A symbol 7” (e.g., forward slash) may be used herein to represent “and / or,” where, for example, “A / B” may imply “A and / or B.”

[0098] 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.

[0099] A WTRU may transmit a physical channel or signal using the same spatial domain filter as the spatial domain filter used for receiving a reference signal (RS), such as a CSI-RS, or an SS block. The WTRU transmission may be referred to as a target, and the received RS or the received SS block may bereferred to as a reference or a source. The WTRU may (e.g., in this case) be said to transmit the target physical channel or signal according to a spatial relation with a reference to an RS or an SS block.

[0100] A WTRU may transmit a first physical channel or signal according to the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel or signal. The first and second transmissions may be referred to as target and reference (e.g., or source), respectively. In such case, the WTRU may be said to transmit the first (e.g., target) physical channel or signal according to a spatial relation with a reference to the second (e.g., reference) physical channel or signal.

[0101] In some examples, a spatial relation may be implicit, for example, configured by RRC or signaled by MAC CE or DCI. For example, a WTRU may transmit (e.g., implicitly transmit) PUSCH and a demodulation reference signal (DM-RS) of PUSCH according to the same spatial domain filter as a sounding reference signal (SRS) indicated by an SRS resource indicator (SRI) indicated in DCI or configured by RRC. In some examples, a spatial relation may be configured by RRC for an SRI or signaled by MAC CE for a PUCCH. A spatial relation may also be referred to as a beam indication.

[0102] A WTRU may receive a first (e.g., target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (e.g., reference) downlink channel or signal. For example, an association may exist between a physical channel (e.g., PDCCH or PDSCH) and the physical channel’s respective DM-RS. An association may exist if / when a WTRU is configured with a quasi-colocation (QCL) assumption type D between corresponding antenna ports, e.g., at least when the first and second signals are reference signals. An association may be configured as a transmission configuration indicator (TCI) state. A WTRU may be indicated as an association between a CSI-RS or an SS block and a DM-RS, for example, by an index to a set of TCI states configured by RRC and / or signaled by a MAC CE. An indication may also be referred to as a beam indication.

[0103] Herein, an SSB may refer to one or more SSB beams (e.g., spatial relations) within a collection of SSBs (e.g., SSB burst). An SSB may refer to a beam (e.g., and visa-versa) or a CSI-RS resource related to the beam. SSB, SSBs, and / or SSB burst may refer to (e.g., loosely refer) to one or more beams transmitted from a TRP or from a transmission point (TP).

[0104] A transmission and reception point (TRP) may be used interchangeably with one or more of a transmission point (TP), a reception point (RP), a radio remote head (RRH), a distributed antenna (DA), a base station (BS), a sector (e.g., of a BS), and / or a cell (e.g., a geographical cell area served by a BS). Multi-TRPs may be used interchangeably with one or more of MTRP, M-TRP, and multiple TRPs.

[0105] A base station, such as a gNB, may use reduced downlink transmission / uplink reception activity without an (e.g., explicit) cell DTX / DRX (C-DTX / C-DRX) pattern, e.g., with restrictions due to WTRU DRXconfigurations and / or any configured transmission / reception, e.g., common channels / signals. A C-DRX may be configured per WTRU. The alignment of the DRX cycles or offsets for different WTRUs may be performed (e.g., only) via RRC. A WTRU may not expect to monitor PDCCH during a WTRU DRX off period, but the WTRU may (e.g., be allowed to) initiate a UL transmission according to configured resources (e.g., using PUCCH, RACH, SR, or CG-PUSCH). Aligning / omitting of DRX patterns across multiple WTRU's may be achieved, for example, via a gNB implementation.

[0106] Cell DTX / DRX may provide one or more mechanisms informing a WTRU whether the cell stays inactive. The one or more mechanisms may include enhancements to a WTRU DRX configuration, e.g., to align / omit DRX cycles or start offsets of DRX (e.g., for WTRUs in connected mode or idle / inactive mode), which may allow longer opportunities for cell inactivity. A cell may not have transmission / reception or may keep (e.g., only) limited transmission / reception, e.g., during a cell DTX / DRX. For example, a cell may not (e.g., need to) transmit or receive one or more (e.g., some) periodic signals / channels, such as common channels / signals and / or WTRU specific signals / channels.

[0107] Cell DTX / DRX may be applied to, e.g., at least, WTRUs in RRC_CONNECTED state. A periodic Cell DTX / DRX (e.g., active and non-active periods) may be configured by a gNB, e.g., via WTRU-specific RRC signalling per serving cell. Cell DTX / DRX mode may be activated / de-activated, for example, via dynamic L1 / L2 signaling and / or WTRU-specific RRC signaling. WTRU-specific and common L1 / L2 signaling may be considered / applied for activating / deactivating a cell DTX / DRX mode. Cell DTX and Cell DRX modes may be configured and operated separately (e.g., one RRC configuration set for DL and another RRC configuration set for UL). Cell DTX / DRX may, e.g., also, be configured and / or operated together. One or more of the following parameters may be configured, e.g., per Cell DTX / DRX configuration: periodicity, start slot / offset, and / or on duration. In some examples, a cell DTX indication may (e.g., also) be part of a system information (SI) update and / or system information block (SIB) signaling. There may be a common time for one or more (e.g., all) WTRUs to determine cell DTX status.

[0108] A WTRU may be configured with multiple cell DRX and / or cell DTX configurations (e.g., simultaneously) in a given serving cell. A WTRU may be configured with a primary or a default cell DTX and / or cell DRX configuration, which the WTRU may apply by default. A WTRU may deactivate one or more cell DTX and / or cell DRX configurations, for example, based on (e.g., upon) reception of signaling activating a (e.g., one) cell DTX and / or cell DRX configuration. A WTRU may activate a cell DTX and / or cell DRX configuration or activate a default cell DTX / DRX configuration, for example, based on (e.g., upon) reception of signaling deactivating a (e.g., one) cell DTX and / or cell DRX configuration. A WTRU may fall back to a (e.g., default) cell DRX and / or cell DTX configuration, for example, based on expiration of a timer.A WTRU may reset a timer, for example, based on reception of DL signaling or data and / or an indication from the network (NW) to remain in a given non-default cell DTX or cell DRX state.

[0109] A network availability state (e.g., NES) or an availability state may refer to a cell state in which the cell or transmission / reception point (TRP) has activated at least one NES technique, which may include one or more of the following: cell DTX, cell DRX, spatial domain adaptation (e.g., where a subset of antenna ports and / or elements are turned off), power domain adaptation (e.g., where a subset of channels are transmitted with reduced power or are muted), and / or the cell or TRP has turned off.

[0110] A WTRU may determine whether it can transmit or receive on (e.g., certain) resources, for example, depending on a network availability state, which may imply 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. An availability state may change from symbol to symbol, slot to slot, frame to frame, and / or on longer duration granularity. An availability state may be determined by a WTRU and / or indicated by a 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.” Availability states may be abstracted by one or more NW configuration parameters and / or values. A 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 (e.g., certain) signals (e.g., presence signals, synchronization, or reference signals) and / or receive (e.g., certain) UL signals. One or more (e.g., some) DL or UL resources may not be available during one or more (e.g., certain) periods of time in one or more availability states, which may enable the network to turn off baseband processing and / or other activities. For example, a WTRU may be configured by RRC with periodic Active and Inactive periods per availability. Some measurement resources (e.g., SSBs or CSI-RS) may be made available (e.g., only) in certain availability states, which may include one or more of the following: radio link monitoring (RLM), beam failure detection (BFD), radio resource management (RRM) measurements, CSI-RS feedback configuration, and / or a different power offset for CSI feedback.

[0111] A WTRU may (e.g., under certain conditions) transmit a request to the network (e.g., a wake-up request) to modify the availability state to a state for which resources that would satisfy WTRU requirements are available.

[0112] A WTRU may determine an availability state, for example, from reception of an availability state indication, which may be received from, for example, L1 / L2 signaling (e.g., a group common DCI or anindication), and / or may (e.g., implicitly) determine an availability state form the reception of (e.g., periodic) DL signalling and / or lack thereof.

[0113] A WTRU may determine if a resource is available for transmission / reception and / or measurements for the determined network availability state, for example, if the resource is applicable in the active availability state. A WTRU may adapt its active connected mode discontinuous reception (C-DRX) cycle, active spatial elements (e.g., antenna or logical ports), active TRPs, paging occasions, and / or the like, for example, as a function of the signaled or determined availability state. A 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. A WTRU may apply an NES parameter set according to the determined or signaled availability state. A WTRU may apply one or more applicable configurations depending on the determined NES state. A set of NES parameters may include, for example, one or more of the following: 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, conditional handover (CHO) or mobility candidates, and / or a set of active TRPs.

[0114] An availability state may be applicable to at least one transmission, reception, and / 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, and / or a range of frequencies within a bandwidth part. In some examples (e.g., if / when an NES state changes in a cell), a WTRU may receive an availability state change indication indicating that the change is (e.g., only) for that cell, for all cells at a same frequency, and / or the same RAT.

[0115] A WTRU may consider the active availability state associated with a cell, carrier, TRP, or frequency band to be “Off,” “Deep sleep,” or “Micro sleep,” for example, based on (e.g., after) reception of a DL signaling that changes the cell’s or TRP’s availability state. For example, a 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). A WTRU may determine an availability state from reception of an availability state indication, which may be received from, for example, L1 / L2 signalling (e.g., a group common DCI or indication) or broadcast signaling associated with an availability state.

[0116] In some examples, an availability state change indication may (e.g., also) be part of SI update or SIB signaling (e.g., in a separate SIB that is not read by legacy WTRUs). There may be a common time for one or more (e.g., all) WTRUs in the cell to determine availability state status.

[0117] In some examples, a WTRU may determine an 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 a (e.g., one of the) configured NES parameters sets to apply or may determine a delta configuration from the current set of parameters, for example, based on determining an NES state change. A WTRU may transmit a feedback / acknowledgment to a gNB, which may be multiplexed with UL data (e.g., part of an UL TB as a MAC CE or a subheader indication), for example, following the reception of NES state change indication.

[0118] In some examples, a WTRU may determine an NES state change from reception of broadcast signaling associated with an NES state indication or change, including signaling in SIB(s) or part of a broadcast or multicast PDSCH. The WTRU may be indicated in an NES state, e.g., explicitly in the SIB. A WTRU may be configured with one or more SIBs, which may be (e.g., exclusively) associated with configuration of NES parameters. A WTRU may be configured to receive a broadcast or multicast indication periodically. A WTRU may determine an indication is mis-detected, for example, 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. A WTRU may start inter-cell, inter-frequency, and / or inter-RAT measurements, start a mobility procedure, and / or start evaluating configured CHO candidates, for example, based on (e.g., following) the determination of a misdetection of the NES state indication.

[0119] A WTRU may (e.g., implicitly) assume / determine an availability state associated with a cell, carrier, TRP, and / or frequency band (e.g., “Off,” “deep sleep,” “micro sleep,” or “dormant”) from at least one of the following: reception of a command or signal indicating a change in availability state; reception of a paging message, paging DCI, paging PDSCH, or a paging related signal (e.g., PEI), such as on a subset of POs (e.g., those aligned with NES DRX cycle or a configured subset of PDCCH resources); a gNB DTX status (e.g., whether the gNB is in active time or an associated activity timer is running); lack of detection of a presence indication; a time in the day; an 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); detection of a PSS only signal or a simplified / stripped down SSB signal; detection of an RS signal (e.g., CSI-RS, PRS, TRS) or the lack thereof; the WTRU’s RRC state (e.g., idle, inactive, or connected mode); whether paging has been received, e.g., within a configured time window; whether system information (e.g., periodic SI or a subset of SIBs) has been received, e.g., within a configured time window; and / or measured channel condition(s) being below or above a threshold.

[0120] A WTRU may (e.g., implicitly) assume / determine an availability state associated with a cell, carrier, TRP, and / or frequency band (e.g., “Off,” “deep sleep,” “micro sleep,” or “dormant”) from reception ofa 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. A WTRU may determine an availability state (e.g., implicitly) form the reception of periodic DL signaling. A WTRU may be configured or specified to associate an availability state with one or more DL signal types (e.g., SSB, partial SSB, and / or one or more periodicities).

[0121] A WTRU may (e.g., implicitly) assume / determine an availability state associated with a cell, carrier, TRP, and / or frequency band (e.g., “Off,” “deep sleep,” “micro sleep,” or “dormant”) from reception of a paging message, paging DCI, paging PDSCH, or a paging related signal (e.g., PEI), such as on a subset of POs (e.g., those aligned with NES DRX cycle or a configured subset of PDCCH resources). A WTRU may assume / determine an availability state, for example, after reception of an indication part of the DCI or PDCCH scheduling paging (e.g., as a function of the P-RNTI, NES-RNTI or based on receiving an indication (e.g., an explicit indication, such as on a reserved bit). A WTRU may assume / determine an availability state, for example, after the reception of a paging message with a certain P-RNTI, a separately configured NES P-RNTI, or the NES group RNTI. A WTRU may assume / determine an availability state after the reception of a paging message with a certain P-RNTI. A WTRU may be configured with one more paging early indication (PEI) subgroup for NES, where a subgroup may be associated with one or more availability states. A WTRU may assume an availability state after reception of a PEI with an NES subgroup, e.g., if the 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. A paging indication may (e.g., further) indicate an alternative cell to monitor paging on while the cell from which the signaling was received is off, sleeping, or in an NES state. A paging indication may (e.g., further) indicate or signal applicable reconfiguration parameters (e.g., for initial access, applicable PRACH resources, applicable SSB / RS occasions, applicable SI cycle, and / or the applicable cell(s) and associated availability states).

[0122] A WTRU may (e.g., implicitly) assume / determine an availability state associated with a cell, carrier, TRP, and / or frequency band (e.g., “Off,” “deep sleep,” “micro sleep,” or “dormant”) from lack of detection of a presence indication. For example, a WTRU may determine an availability state associated with the cell (e.g., “off” or “deep sleep”) if a presence indication was not detected on one or more presence indication occasion. For example, a WTRU may assume or change a cell’s availability state after a number of consecutive misdetections or after a timer expires following no detection of a presence signal. A WTRU may determine an availability state is active or de-active after expiry of a timer associated with the availability state. A timer may be configured and / or maintained in connected mode only, or (e.g., also) in other states (e.g., idle and inactive states). For example, a WTRU may determine an availability state (e.g.,implicitly) form the lack of reception of periodic DL signaling. For example, a WTRU may be configured with a signal quality threshold (e.g., an RSRP threshold). The WTRU may assume that this availability state is not active and / or may assume a different availability state, for example, 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. This criterion may be coupled with lack of detection of an identifying sequence of the presence signal (e.g., detection of the PSS sequence).

[0123] A WTRU may (e.g., implicitly) assume / determine an availability state associated with a cell, carrier, TRP, and / or frequency band (e.g., “Off,” “deep sleep,” “micro sleep,” or “dormant”) from a time in the day. For example, a WTRU may be configured to (e.g., automatically) assume / determine an availability state (e.g., “off,” “sleep,” or “dormant”) for a configured subset of cells (e.g., capacity boosting cells) depending on 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.

[0124] A WTRU may (e.g., implicitly) assume / determine an availability state associated with a cell, carrier, TRP, and / or frequency band (e.g., “Off,” “deep sleep,” “micro sleep,” or “dormant”) from a measured channel condition(s) being below or above a threshold. For example, a 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, a WTRU may use degradation in measurements of SSBs or CSI-RS, e.g., in combination with other signaling, to determine the NES state. For example, a configured window following a DCI reception may be used to measure SSBs and / or CSI-RS for degradation. A WTRU may determine that the NES state has changed and assume / determine associated actions for the NES state (e.g., trigger for CHO candidate selection or for group scheduling for a mobility command), for example, if a delta of SSB-RSRP drop is measured.

[0125] A 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. A WTRU may assume the same availability state for multiple (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 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 that 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 bescrambled 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 a go-to-sleep signal, e.g., a predefined sequence. A WTRU may expect / determine a reduced activity level over a specific time duration, for example, if / when the WTRU detects a sequence. A WTRU may activate C-DRX for the period of time indicated. Multiple (e.g., two) sequences may (e.g., alternatively) be used to indicate regular activity and reduced activity.

[0126] Signaling within a PDCCH or an activity indication may include at least one of the following: an expected activity level of the associated gNBs / cells over a time interval (e.g., an availability state); transmission and / or reception attributes (e.g., defined) for a (e.g., each) activity level (e.g., availability state); a set of configurations associated with an activity level for use / application if / when the activity level is indicated (e.g., an NES parameter set); a time interval over which an activity level is assumed, which may be signaled in the PDCCH or part of the activity indication; and / or a time interval over which an activity level is assumed, which may be predetermined.

[0127] Signaling within a PDCCH or an 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. The activity levels may, for example, include 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.

[0128] Signaling within a PDCCH or an activity indication may include transmission and reception attributes, which may be defined for a (e.g., each) activity level (e.g., availability state). For example, during reduced activity, a WTRU may not (e.g., be expected to) monitor one or more (e.g., certain) PDCCH search spaces (e.g., including (all) SSs), receive one or more (e.g., all) types of PDSCH, transmit PUCCH / PUSCH, and / or perform one or more (e.g., certain) measurements. A WTRU may start or stop monitoring PDCCH and / or TCI states associated with a determined NES state, e.g., including PDCCH resources or TCI states associated with (de)activated TRPs or spatial elements.

[0129] A set of configurations may be associated with an activity level, which may be used / applied if / when the activity level is indicated (e.g., an NES parameter set). For example, a set of configurations may include SS configurations, CSI reporting configurations, indices of transmitted SSBs, etc. A (e.g., each) set of configurations may have an attribute associated with an activity level, e.g., a tag that may be set to “reduced activity.”

[0130] A time interval over which an activity level is assumed may be signaled in the PDCCH or part of the activity indication. A time interval may be indicated, for example, using a bitmap. A e.g., each, bit in thebitmap 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.

[0131] A time interval may be indicated with a start time and / or a length of interval. A start time may be defined. For example, a start time may be determined by adding a fixed offset to the time that the indication is received. The length of the interval may be configured or signaled in the indication PDCCH.

[0132] A time interval over which an activity level is assumed may be predetermined. A WTRU may assume an interruption delay (e.g., or, more generally, a time until the NES state changes), for example, 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.

[0133] A 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, for example, if the resource is applicable in the active availability state. A WTRU may determine that a subset of measurement resources and / or signals (e.g., SSBs, CSI-RS, TRS, PRS, and / or the like) are not applicable in one or more (e.g., certain) availability states. A WTRU may determine that a subset of uplink or downlink resources (e.g., PRACH, PUSCH, PUCCH, and / or the like) are not applicable in one or more (e.g., certain) availability states. A WTRU may transmit one or more (e.g., some) uplink signals (e.g., only) in a subset of NW availability states (e.g., SRS, pSRS, PRACH, UCI, and / or the like).

[0134] Synchronization signals and procedures may be implemented in a network (e.g., 5G NR). Downlink Synchronization may be the process in which a WTRU detects a radio frame boundary (e.g., the exact timing when a radio frame starts) and OFDM symbol boundary (e.g., the exact timing when an OFDM symbol starts). Downlink synchronization may be performed, for example, by detecting and analyzing a synchronization signal block (SSB).

[0135] A Synchronization Signal and PBCH block (e.g., SSB) may include primary and secondary synchronization signals (e.g., PSS and SSS), e.g., each occupying 1 symbol and 127 subcarriers, and a PBCH (e.g., spanning across three (3) OFDM symbols and 240 subcarriers), but on one OFDM symbol leaving an unused part in the middle for a secondary synchronization signal (SSS), as shown by example in FIG. 2. The possible time locations of SSBs within a half-frame may be determined, for example, by subcarrier spacing and / or the periodicity of the half-frames where SSBs are transmitted, which may be 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).

[0136] Multiple SSBs may be transmitted within the frequency span of a carrier. The PCIs of SSBs transmitted in different frequency locations may not be unique, e.g., different SSBs in the frequency domain may have different PCIs. An SSB associated with an RMSI may be referred to as a cell-defining SSB (CD- SSB). A PCell may (e.g., always) be associated with a CD-SSB located on the synchronization raster.

[0137] FIG. 2 illustrates an example of a time-frequency structure of an SSB.

[0138] Polar coding may be used for PBCH. A WTRU may assume a band-specific sub-carrier spacing for the SSB, for example, 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.

[0139] Cell search may be a procedure that a WTRU may use to acquire time and frequency synchronization with a cell and detect the cell ID of the cell. NR cell search may be based on the primary and secondary synchronization signals, e.g., and PBCH DMRS, located on the synchronization raster.

[0140] System Information (SI) may be divided into a master information block (MIB) and a number of system information blocks (SIBs). An MIB may (e.g., always) be transmitted on the BCH (e.g., with a periodicity of 80 ms and repetitions made within 80 ms). An MIB may include one or more parameters that may be used to acquire SIB1 from the cell. An SIB1 may be transmitted on the DL-SCH (e.g., with a periodicity of 160 ms and / or variable transmission repetition periodicity within 160 ms). The default transmission repetition periodicity of SI B1 may be configured (e.g., 20 ms). Transmission repetition periodicity may be up to network implementation. Minimum system information (MSI) to operate on a cell may include MIB and SIB1.

[0141] An SIB1 repetition transmission period may be 20 ms, e.g., for SSB and CORESET multiplexing pattern 1. An SIB1 transmission repetition period may be the same as the SSB period, e.g., for SSB and CORESET multiplexing pattern 2 / 3. SIB1 may include information regarding the availability and scheduling (e.g., mapping of SIBs to SI message, periodicity, Sl-window size, and / or the like) of other SIBs, which may include an indication whether one or more SIBs are (e.g., only) provided on demand and / or other information. For example, SIB1 may (e.g., additionally) indicate the configuration needed / used by the WTRU to perform an SI request, e.g., if SIB1 indicates one or more SIBs are provided on demand. SIB1 may be a cell-specific SIB.

[0142] The Master Information Block (MIB) on PBCH may provide a WTRU with one or more 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 , in which case the WTRU may be pointed to another frequency from where to search for an SSB that is associated with anSIB1 and / or a frequency range where the WTRU may assume no SSB associated with SIB1 is present. The indicated frequency range may be confined within a contiguous spectrum allocation of the same operator in which the SSB is detected.

[0143] An (e.g., each) SSB within an SSB burst set (e.g., all SSBs within a (5 ms) period of an SSB transmission) may be assigned with a unique number, e.g., starting from 0 and increasing by 1. The unique number may reset, e.g., to zero (0), in the next SSB burst set (e.g., next 5 ms span after SSB transmission cycle, for example, after a default cycle of 20 ms). A unique number (e.g., SSB Index) may be indicated to a WTRU, for example, via PBCH DMRS and / or 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 (e.g., two (2)) least significant bits (LSBs), for example, for L = 4, or the three (3) LSB bits, for example, for L > 4 , of an SSB index per half frame from a one-to-one mapping with an index of the DMRS sequence transmitted in the PBCH. For example (e.g., for L = 64), a WTRU may determine the three (3) MSB bits of the SS / PBCH block index per half frame by PBCH payload bits. FIG. 3 shows an example of an SSB burst with a periodicity (e.g., of 20 ms).

[0144] FIG. 3 illustrates an example of SSB beam sweeping within SSB burst sets. One or more beam failure detection and recovery procedures may be implemented, e.g., to support reliable and uninterrupted communication between the WTRU and the base station. Beam failure detection may include monitoring of beam-specific reference signals. A WTRU may (e.g., continuously) receive beam-specific reference signals from the base station, allowing the WTRU to track beamforming performance. A WTRU may trigger a beam failure event, for example, if the quality of the received signals deteriorates below a threshold, indicating a potential beam failure. A WTRU may initiate a beam failure recovery procedure, for example, if / when a beam failure event is detected. A WTRU may (e.g., first) try to restore the connection with the base station, for example, by using the last known beamforming configuration. A WTRU may (e.g., if an attempt to restore a connection fails) search for alternative beams and / or perform beam sweeping, where the WTRU scans one or more different beamforming configurations, e.g., in search of a stronger and more reliable beam.

[0145] A WTRU (e.g., in a beamformed NR system) may be configured to maintain one or more (e.g., multiple) beam pairs. A WTRU may monitor one or more (e.g., certain) periodic SSBs and / or CSI-RS on a serving DL beam to assess beam quality and / or compute a corresponding quality metric. A WTRU’s PHY entity may report a beam failure instance (BFI) to the MAC sub-layer, for example, if the beam’s quality in an RS period is below a configured threshold.

[0146] Lost beam pairs may be re-established (e.g., in a faster manner compared to an RLM / RLF procedure), for example, by employing a BFR procedure (e.g., in a WTRU’s MAC layer) 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 PCell and / or SCell.

[0147] 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. A BFR request may be triggered to notify the serving gNB that a beam failure has been detected, for example, if the BFI counter exceeds a certain maximum number of BFIs.

[0148] The MAC entity may reset the BFI counter (e.g., only) after a beam failure detection timer (BFD_timer) has expired. A reset may help provide some hysteresis in the detection function. A WTRU may (e.g., in such a case) reset the BFD timer each time 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 the PHY layer for (e.g., three) consecutive CSI-RS periods (e.g., if the BFD timer is configured to three (3) CSI-RS periods).

[0149] A WTRU may report a BFR request, for example, by initiating a random access procedure with (e.g., certain) parameter values (e.g., PreambleTransMax, power ramping step, and / or the target received preamble power). A random access procedure may be used for beam re-establishment, for example, as the WTRU may select (e.g., an appropriate) PRACH preamble and / or PRACH resource dependent on the best measured downlink beam (e.g., or DL SSB). A WTRU may reestablish a beam pair if / when the WTRU may determine an association between DL beams and UL preambles and / or PRACH occasions. The downlink beam selected by the WTRU may be tested, for example, by receiving the random access response (RAR) on the DL beam. The reestablishment RA procedure may be made faster, for example, if the gNB configures a (e.g., certain) set of contention-free PRACH preambles / resources, which may be prioritized for selection by the WTRU upon initiating the RA procedure. Beam failure recovery for a PCell may be considered complete, for example, upon completion of the Random Access procedure.

[0150] A beam failure and detection procedure may (e.g., also) address one or more secondary cells. A WTRU may trigger beam failure recovery by transmitting a BFR MAC CE for a secondary cell (SCell), for example, if / when beam failure is detected on the SCell. A WTRU may (e.g., also) select a suitable beam for the affected SCell, for example, if there is an alternative available that includes this information (e.g., along with details about the beam failure) in the BFR MAC CE. Beam failure recovery for an SCell may be considered complete, for example, based on (e.g., 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.

[0151] One or more operators may (e.g., often) deploy macro cells overlaid with a number of small cells. A macro cell may transmit SSB and / or SIBs. One or more small cells may not always have traffic. Networks may (e.g., therefore) consume un-necessary energy by transmitting SSBs that may not be necessary, e.g., particularly in low load scenarios where the network may be able to save some energy if the network does not transmit one or more SSBs according to fixed patterns and periodicities. A set of small cells may (e.g., for this reason) not transmit SSBs but may (e.g., only) transmit pre-sync or discovery signals. The signal may be a combination of PSS and SSS (e.g., PSS+SSS), for example.

[0152] A WTRU performing initial access may discover (e.g., receive) a pre-sync signal from a first cell (e.g., an NES cell) and / or SSB / SIB-1 from a second cell (e.g., a macro cell). Macro coverage may overlap with one or more different small cells in one or more different areas. The network may (e.g., want to) have one or more WTRUs performing initial access camped on one or more suitable small cells.

[0153] A WTRU may perform an initial access procedure and determine a RACH configuration for one or more small cells transmitting (e.g., only) a discovery and / or a pre-sync signal.

[0154] Network Energy Saving (NES) terminology may be described herein. A cell DTX active period may be a duration of time over which a configured cell DTX pattern is active (e.g., periods of time during On Duration periods of a Cell DTX pattern). A WTRU may (e.g., be predefined to) monitor PDCCH and / or one or more other DL signals and channels, e.g., during a cell DTX active period of time. Monitoring may be applicable (e.g., only) after a cell DTX configuration has been indicated by the NW to be activated.

[0155] A cell DTX inactive period may be 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). A cell DTX inactive period may be applicable (e.g., only) after a cell DTX configuration has been indicated by the NW to be activated.

[0156] A cell DRX active period may be a duration of time over which a configured cell DRX pattern is active (e.g., periods of time during On Duration periods of a Cell DRX pattern). A WTRU may (e.g., be predefined to be allowed to) transmit one or more UL signals and / or on one or more UL channels during a cell DRX active period of time. A cell DRX active period may be applicable (e.g., only) after a cell DRX configuration has been indicated by the NW to be activated.

[0157] A cell DRX inactive period may be a 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). A cell DRX inactive period may be applicable (e.g., only) after a cell DRX configuration has been indicated by the NW to be activated.

[0158] An activated Cell DRX / DTX may be a state of a configured cell DRX or Cell DTX pattern, e.g., where the state has been activated by L1 / L2 DL signalling, RRC (re)-configuration, and / or cell common configurations, and has not been de-activated.

[0159] A de-activated Cell DRX / DTX may be a state of a configured cell DRX or Cell DTX pattern, e.g., where the state has been deactivated by L1 / L2 DL signaling, RRC (re)-configuration, and / or cell common configurations.

[0160] A link between availability state, NES state, and / or Cell DTX / DRX. Herein, terms may be used interchangeably. The WTRU may determine a cell DTX state (e.g., implicitly) from a determined active availability state, and / or visa-versa. The WTRU may determine a cell RTX state (e.g., implicitly) from a determined active availability state, and / or visa-versa.

[0161] The terms “alternative cell” and “stable cell” may be used interchangeably herein. A WTRU may be configured with a list of stable cells (e.g., alternative cells that will not turn off, such as one or more (some) macro cells). The list may be a list of alternative cells per serving / camped cell or a general list of PCIs for the whole NW, Tracking area, etc. A WTRU may be configured with a measurement object configuration for alternative cells. A WTRU may be configured or predefined with one or more stable cells to perform initial access, mobility, and / or cell reselection on in the event the current serving cell (e.g., an NES cell) is turned off or activates an NES state. A WTRU may be configured per broadcast or dedicated signaling with a list of stable cells, e.g., per serving cell, per gNB, per PLMN, and / or per network identity. Stable cells may correspond to cells that do not apply and / or are not configured to apply NES techniques (e.g., non-NES cells).

[0162] An NES cell may be 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.). A cell may be designated as an NES cell, for example, (e.g., only) if the cell has activated an 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.

[0163] An Ref-PCell or Anchor cell may be a reference primary cell from which a WTRU may rely on for initial access, RLM, BFD, and / or paging procedures. A Ref-PCell may be associated with one or more other PCells or SCells, which may be NES cells. System information broadcasted from the Ref-PCell may advertise / indicate the existence of other associated cells with the Ref-PCell, e.g., including configurations associated with NES (e.g., pre-synch signal, transmission occasions, PRACH configurations, and / or NES state cycle length and information / configuration). The terms “Ref-PCell” and “Anchor cell” may be used interchangeably.

[0164] System information transmission and acquisition terminology is described herein. A synchronization signal transmission may use a low power transmission (Tx) and power amplifier. A gNB may be equipped with a low power transmitter and / or power amplifier (PA). The synchronization sequences, e.g., including legacy SSB or SSBs described herein, may be transmitted by the gNB using a lower power Tx and / or PA.

[0165] The gNB transmission of sync signals using a low power Tx and PA may be associated with a cell NES state. Sync signals may be transmitted using a low power Tx and PA, for example, if / when the associated cell is in NES InActive state. Sync signals may be transmitted using a normal Tx and PA, for example, if / when the associated cell is in NES Active state.

[0166] FIG. 4 illustrates an example flow diagram 400 of a WTRU performing / implementing multi-cell random access with on-demand SSB. As illustrated in FIG. 4, a WTRU may detect / receive a pre-sync signal from a first cell, e.g., an NES cell. A WTRU may be configured to detect / receive one or more presync signals as part of an initial access procedure. A pre-sync signal may be, or may include, a discovery signal, an SSB signal, a slim version of SSB signal, e.g., PSS, SSS or PSS+SSS, and / or the like. The SSB signal associated with the pre-sync signal described herein may not be a full SSB signal.

[0167] In examples, the WTRU may determine the cell ID and / or a transmitting beam index (e.g., a beam-index and / or a transmitting beam) from a pre-sync signal. For example, the WTRU may determine a cell (e.g., a first cell) transmitting the pre-sync signal and / or a transmitting beam index associated with the pre-sync signal based on a property of the pre-sync signal. The property associated with the pre-sync signal may be, or may include, at least one of a time, a frequency, a sequence selection, a phase, a sequence identification (ID) associated with the pre-sync signal.

[0168] In examples, the WTRU may (e.g., determine to) process (e.g., further) a pre-sync signal received from a first cell, for example, if the pre-sync-ReceivedPower is larger than a first threshold. The threshold may be known to a WTRU, e.g., through pre-configuration. A WTRU may be pre-defined with the threshold. In some examples, a WTRU may receive the threshold from the network during a network connection (e.g., during one of the WTRU’s last connections to the network).

[0169] In examples, the WTRU may determine the cell identity, e.g., PCI, of the first cell from the received pre-sync signal of the first cell. A WTRU may determine a transmitting beam index (e.g., a beamindex and / or a transmitting beam) associated with the received pre-sync signal of the first cell. A WTRU may determine a cell ID and or a transmitting beam index (e.g., a beam-index and / or a transmitting beam) associated with the pre-sync signal, e.g., based on a property of the pre-sync signal. For example, the property (e.g., physical property) associated with the pre-sync signal may be, or may include one or moreof the following: a time, a frequency, a sequence selection, a phase, sequence ID, etc. In some examples, the received sequences may provide the cell identity through a network arrangement (e.g., as in 5G NR).

[0170] The WTRU may determine whether a condition is satisfied. For example, the condition being satisfied may be, or may include, at least one of a determination that a received power associated with the pre-sync signal is greater than a threshold, a determination that a full SSB is not received from the first cell, or a determination the first cell is in an energy savings state. If the condition is satisfied (e.g., based on a determination that the condition is satisfied), the WTRU may receive a transmission from a second cell.

[0171] A WTRU may receive one or more full SSBs from a second cell. A WTRU may (e.g., determine to) search one or more SSBs from a second cell. A WTRU may (e.g., determine to) search for one or more SSBs from a second cell, for example, if at least one of the following condition is met: a pre-sync received power from the first cell is greater than a first threshold (Threshold 1); a full SSB is not received from the first cell; the first cell is determined to be in an NES state; and / or the RSRP from a second cell is greater than a second threshold (e.g., RSRP_from_second cell < Threshold 2). A WTRU may be pre-configured or pre-defined with a first threshold (Thresholdl) and / or a second threshold (Threshold 2).

[0172] In examples, the WTRU may receive a transmission from a second cell if the WTRU determines that the condition described herein is satisfied. For example, if the WTRU determines that at least one of a determination that a received power associated with the pre-sync signal is greater than a threshold, a determination that a full synchronization signal block (SSB) is not received from the first cell, or a determination the first cell is in an energy savings state has been satisfied, the WTRU may receive a transmission from a second cell. The transmission from the second cell may be or may include at least one of an SSB or a SIB.

[0173] In some examples, a WTRU may (e.g., determine to) search one or more SSBs from a second cell on the same carrier frequency where the WTRU detects (e.g., receives) a pre-sync signal. In some examples, a WTRU may (e.g., determine to) search one or more SSBs from a second cell on a different carrier frequency where the WTRU detects (e.g., receives) a pre-sync signal.

[0174] In some examples, a WTRU may (e.g., determine to) search for one or more SSBs from a second cell based on an indication in the pre-sync signal received from the first cell. The indication may be transmitted through any of the physical properties of the pre-sync signal received from the first cell, e.g., time resource, frequency resource, sequence selection, sequence phase, etc. The indication may be an indication for the WTRU to find an SSB and / or one or more SIBs from a different cell. The indication may provide one or more parameters related to one or more of the following to search SSB for a second cell: atime resource to detect an SSB; a frequency resource to detect an SSB; a carrier frequency; and / or a cell ID, e.g., a PCI and / or a set of cell IDs for a second cell.

[0175] In some examples, a WTRU may (e.g., determine to) search for one or more SSBs from a second cell where the WTRU determines the timings for the second cell SSBs based upon the pre-sync signal received from the first cell.

[0176] In some examples, a WTRU may (e.g., determine to) search for one or more SSBs from a second cell where the WTRU determines the cell ID of the second cell based upon the pre-sync signal received from the first cell.

[0177] As described herein, a WTRU may receive a transmission from a second cell. For example, the transmission from the second cell may be, or may include, an SSB and / or SIB-1. The WTRU may decode the transmission (e.g., an SSB and / or SIB-1) from a second cell. In some examples, the WTRU may receive system information blocks (e.g., additional system information blocks) from a second cell.

[0178] As described herein, the transmission may be associated with at least one SSB from the second cell. The WTRU may determine (e.g., may further configured to) determine the second cell to receive the at least one SSB based on at least one of a same frequency that the pre-sync signal is detected, a different frequency that the pre-sync signal is detected, an indication associated with the pre-sync signal, or a parameter comprising at least one of a time resource to detect the at least one SSB, a frequency resource to detect the at least one SSB, a carrier frequency associated with the at least one SSB, or a cell ID associated with the at least one SSB.

[0179] A WTRU may determine a RACH configuration for the first cell. For example, the WTRU may determine a RACH configuration based on the transmission from the second cell and the pre-sync signal. The RACH configuration may be, or may include, an association of the pre-sync signal to at least one physical RACH occasion (RO) associated with the first cell. The pre-sync signal may be associated with the first cell. The RACH configuration may be (e.g., may further be), may include (e.g., may further include), at least one of: a system timing associated with the first cell and a first cell ID, an association of a transmitting beam (Tx beam) to the physical RO associated with the first cell, or a partition of RACH preambles with the RO or the TX beam associated with accessing the first cell.

[0180] A WTRU may determine a PRACH configuration for the first cell, for example, based on one or more of the following: a pre-sync signal received from the first cell; and / or an SSB / SIB-1 received from the second cell.

[0181] A WTRU may determine one or more of the following configuration parameters for the first cell: the system timing of the first cell and the cell ID; association of first cell Tx-beam to ROs of the first cell;partition of RACH preambles associated with accessing the first cell; and / or association of first cell SSBs to first cell ROs, e.g., for preamble re-transmission on the first cell.

[0182] In some examples, a WTRU may determine the system timing of the first cell based on the presync signal of the first cell and the SSB and / or SIB-1 of the second cell. In some examples, a WTRU may (e.g., be pre-configured to) derive the system timing of the first cell from the pre-sync timing and the system frame number (SFN) of the second cell. A WTRU may derive the SFN of the second cell from the SSB of the second cell. In some examples, a WTRU may determine the system timing of the first cell, e.g., SFN of the first cell, equal to the system timing of the second cell, e.g., SFN of the second cell, if configured. In some examples, a WTRU may determine the SFN of the first cell equal to SFN of the second cell with an offset. The offset may be pre-defined to the WTRU. In some examples, the offset may be indicated by the second cell, e.g., through SIB-1. In some examples, the WTRU may determine the offset for the first cell through its pre-sync signals or determined identity.

[0183] In some examples, a WTRU may determine a beam index e.g., a pre-sync beam index or an SSB beam index, for the first cell, e.g., based upon the detected beam of the second cell. The terms a transmitting beam index, a beam index, or a transmitting beam may be used interchangeably. A WTRU may be (pre)configured to map a detected beam index of the second cell to a beam index of the first cell.

[0184] In some examples, a WTRU may determine a beam index of the first cell based on the detected beam index of the second cell e.g., from the SSB of the second cell, and the information received in the SIB-1 of the second cell. The SIB-1 of the second cell may provide a mapping to determine a beam index of the first cell, for example, based on the detected beam index of the second cell. The SIB-1 of the second cell may provide the beam mapping information for a number of NES cells.

[0185] A WTRU may evaluate one or more conditions for PRACH transmission on the first cell. A WTRU may (e.g., determine to) transmit RACH on the first cell, for example, if at least one of the following is met: a full SSB is not received from the first cell; the first cell is determined to be in NES state; RSRP_from first cell > Threshold 1 ; and / or RSRP_from_second cell < Threshold 2.

[0186] A WTRU may determine a suitable RACH preamble, RO, and / or other RACH transmission parameters for the first cell, for example, if the WTRU determines to transmit RACH on the first cell.

[0187] A WTRU may (e.g., determine to) transmit RACH on the second cell, for example, if the WTRU determines to not transmit RACH on the first cell.

[0188] A WTRU may determine an RO that is associated with the first cell and / or a RACH preamble for the first cell. For example, the WTRU may determine an RO that is associated with the first cell and a preamble based on the pre-sync signal and / or the RACH configuration for the first cell. A WTRU maydetermine a suitable RO and / or a suitable RACH preamble to transmit RACH on the first cell. The WTRU’s determination of an RO and / or a RACH preamble for the first cell may be based on, for example, one or more of the following: a pre-sync signal of the first cell; a WTRU determined Tx-Beam of the first cell; a (e.g., one) measured SSB index, e.g., the SSB index with highest RSRP, of the second cell; a WTRU determined first cell system timing; system timing of the second cell, e.g., as received in SSB / SIB-1 of the second cell; and / or WTRU determi ned / selected RACH configuration received from the second cell, e.g., in SIB-1.

[0189] A WTRU may transmit the preamble on the RO that is associated with the first cell. For example, a WTRU may transmit a first RACH preamble on the first cell. A WTRU may perform a RACH procedure with determined parameters on the first cell. In some examples, a WTRU may transmit RACH preamble Msg 1 on the first cell.

[0190] A WTRU may transmit the RACH preamble to the first cell with a transmission power. The transmission power may be determined, e.g., based on the use of pre-sync signal from the first cell as pathloss reference. The WTRU may be configured to apply an offset to the pathloss reference and / or to the determined transmission power. In examples, the offset may be based on the energy saving state of the first cell. In examples, the offset may be determined, by the WTRU, based on the energy saving state of the first cell and / or based on the pre-sync signal. In examples, the WTRU may receive the offset from the second cell, e.g., as part of the RACH configuration and / or a separate indication.

[0191] In some examples, a WTRU may transmit RACH Msg Ato the first cell. In some examples, a WTRU may transmit RACH on the first cell using a transmit beam. The WTRU may determine a transmit beam using one or more of the following: a WTRU transmit beam that corresponds to the WTRU receive beam used to determine the Tx-beam of the pre-sync signal from the first cell; a transmit beam that corresponds to one or more of the WTRU receive beams used to detect one or more Tx-beams of the presync signal from the first cell, for example, if the WTRU receives more than one beam formed instance of the pre-sync signal (e.g., a WTRU may select the best / strongest, pre-sync signal to determine a transmit beam); a transmit beam that corresponds to a WTRU receive beam through which the WTRU detects the pre-sync signal from the first cell; a transmit beam that corresponds to the WTRU receive beam through which the WTRU detected the SSB of the second cell; and / or a transmit beam that corresponds to the WTRU receive beam through which the WTRU detected the SSB used to determine the SSB index of the second cell SSB.

[0192] A WTRU may monitor RA response and / or SSB from the first cell. A WTRU may monitor a RACH response from the first cell, for example, based on (e.g., upon) transmitting a first RACH message to the first cell, e.g., Msg 1 or Msg A.

[0193] In some examples, a WTRU may monitor an SSB from the first cell while an RAR window is running for the WTRU’s transmitted RACH preamble. For example, the processor is configured to monitor an RAR from the first cell during an RAR window. The RAR window may be preconfigured and / or received from a base station (e.g., a gNB).

[0194] In examples, the WTRU may monitor an RAR from the first cell during an RAR window. The WTRU may determine whether the RAR is received. If the RAR is received (e.g., based on a determination that the RAR is received), the WTRU may determine a resource to transmit a message. The WTRU may transmit the message on the resource.

[0195] In examples, the WTRU may determine whether the RAR is received. If the RAR is not received (e.g., based on a determination that the RAR is not received on the first cell), the WTRU may determine that at least one SSB is received from the first cell. Based on the determination that the at least one SSB is received from the first cell, the WTRU may transmit a preamble (e.g., a second preamble) on the RO that is associated with the first cell. The RO used for the second preamble transmission may be based on (e.g., further based on) a measured SSB associated with the first cell.

[0196] In examples, the WTRU may determine whether the RAR is received. If the RAR is not received (e.g., based on a determination that the RAR is not received on the first cell), the WTRU may determine whether a number of retransmissions of the preamble is above a threshold. If the number of retransmission is above the threshold (e.g., based on a determination that the number of retransmissions of the preamble is above the threshold), the WTRU may transmit the preamble on the second cell.

[0197] In examples, the WTRU may determine whether the RAR is received. The WTRU may determine whether a fallback indication is received in the RAR on the first cell. If the fallback indication is received (e.g., based on a determination that the fallback indication is received), the WTRU may perform a RACH procedure on the second cell.

[0198] In examples, the WTRU may determine that a reference signal receive power (RSRP) associated with the second cell is below a threshold (e.g., a second threshold). If the RSRP is below the threshold (e.g., based on the determination that the RSRP is below the second threshold), the WTRU may perform a RACH transmission on the first cell.

[0199] In some examples, a WTRU may monitor for a RACH response and / or SSB after the WTRU’s transmission of a RACH preamble on the first cell. A WTRU may receive SSBs from the first cell. A WTRUmay receive one or more SSBs from the first cell. A WTRU may (e.g., based on receiving SSB(s) from the first cell) determine a beam index, e.g., SSB beam index, for the first cell. The beam index may correspond to a (e.g., one) measured / detected SSB from the first cell. In some examples, the beam index may correspond to the SSB received with largest RSRP.

[0200] In some examples, a WTRU may receive SIB-1 from the first cell. A WTRU may (e.g., based on the received SSB and / or SIB-1 from the first cell) determine one or more of the following: a beam index of the first cell; system timing, e.g., SFN, of the first cell; and / or A RACH configuration for the first cell, which may include SSB to RO mapping for the first cell, RACH preamble partitioning, power ramping parameters, and / or contention free RACH resource and configuration.

[0201] A WTRU may transmit a second RACH preamble based on / upon receiving an SSB from the first cell. A WTRU may transmit a RACH preamble, e.g., a second RACH preamble, on the first cell.

[0202] In some examples, a WTRU may (e.g., determine to) transmit a RACH preamble, e.g., a second RACH preamble, on the first cell if the WTRU does not receive a RACH response from the first cell in response to the WTRU’s first RACH transmission within a configured duration.

[0203] In some examples, a WTRU may (e.g., determine to) transmit a RACH preamble, e.g., a second RACH preamble, on the first cell if the WTRU does not receive an SSB or a RACH response from the first cell in response to the WTRU’s first RACH transmission within a configured duration.

[0204] A WTRU (e.g., that does not receive / detect an SSB from the first cell) may determine the RACH configuration and parameters for a RACH transmission (e.g., the second RACH preamble / transmission) in the same manner as for the first RACH transmission on the first cell. A WTRU may (e.g., determine to) apply a power ramping counter for a RACH preamble transmission, e.g., second RACH transmission, on the first cell. A WTRU may use a default power ramping configuration or a power ramping configuration received from the second cell.

[0205] In some examples, a WTRU may (e.g., determine to) transmit a RACH preamble, e.g., a second RACH preamble, on the first cell if the WTRU receives one or more SSBs from the first cell. A WTRU may determine the RACH configuration and parameters for RACH transmission on the first cell based on the SSB received from the first cell. A WTRU may receive an SSB from the first cell, for example, after the WTRU’s first RACH transmission on the first cell.

[0206] A WTRU may determine a (e.g., suitable) RACH preamble and RO for a second RACH transmission on the first cell, for example, based on the detected SSB index of the first cell and the SSB to RO mapping received from the second cell.

[0207] The detected SSB index of the first cell may be the SSB index of a (e.g., one) measured SSB from the first cell. In some examples, a WTRU may select the SSB index of the best measured SSB, e.g., the SSB with the largest RSRP values. In some examples, a WTRU may select an (e.g., any) SSB index among the measured SSBs with an RSRP of a PBCH larger than a (e.g., configured) threshold.

[0208] A WTRU may receive an SSB and at least one SIB, e.g., SIB-1 , from the first cell, for example, after the WTRU’s first RACH transmission on the first cell.

[0209] A WTRU may determine a (e.g., suitable) RACH preamble and RO for a second RACH transmission on the first cell, for example, based on the detected SSB index of the first cell and the SSB to RO mapping received from the first cell.

[0210] A WTRU may perform a RACH transmission on the second cell. A WTRU may (e.g., determine to) transmit RACH on the second cell.

[0211] A WTRU may (determine to) transmit RACH on the second cell, for example, if the WTRU does not receive a (e.g., any) RACH response from the first cell, for example, after N transmissions of RACH preamble on the first cell (e.g., where N may be a configuration parameter). The N transmission may be retransmission of the preamble.

[0212] A WTRU may determine to transmit RACH on the second cell, for example, if the WTRU receives a RACH response from the first cell with a fallback indication. A WTRU may receive a fallback indication from the first cell in the backoff indicator and / or another indication, such as a (e.g., special) bit in the RACH response. The WTRU may be configured / defined to interpret the (e.g., special) bit as fallback indicator to the second cell.

[0213] In some examples, a WTRU may receive an UL grant for MSG3 transmission to the second cell in the RACH response from the first cell. A WTRU may (e.g., then) transmit MSG3 on the second cell as per its received grant from the first cell.

[0214] In some examples, a WTRU may determine the RACH configuration and parameters for RACH transmission on the second cell based on the SSB and SIB-1 received from the second cell. In some examples, a WTRU may transmit RACH on the second cell with a higher initial power if the WTRU has already transmitted at least one RACH transmission on the first cell. For example, a WTRU may use higher power ramping counters for a RACH transmission on the second cell. The use of a higher or aggressive power ramping counter may be subject to the WTRU having made at least one or more RACH transmissions on the first cell through the configurations received from the second cell.

[0215] As described herein and as illustrated in FIG. 4, a WTRU may perform multi-cell random access with on-demand SSB. A WTRU may detect (e.g., receive) a pre-sync signal from a first cell (e.g., an NEScell) and an SSB from a second cell. The WTRU may, e.g., based on the detection / reception, determine a RACH configuration of the first cell from the SSB / SIB (e.g., SIB-1) on the second cell. The WTRU may perform random access using both cells, for example, by performing a first preamble transmission with a sub-optimal quasi-colocation (QCL) assumption regarding the first cell. The WTRU may receive an (e.g., on-demand) SSB. The WTRU may re-transmit a physical random access (PRACH) preamble, for example, based upon the on-demand SSB. The WTRU may fall back to the second cell, for example, if a RAR is not received.

[0216] A WTRU may detect (e.g., receive) a pre-sync (e.g., discovery) signal, such as a combination of a PSS and an SSS (e.g., a PPS plus an SSS) (e.g., with some modification), from a first (e.g., small) cell, e.g., as illustrated in FIG. 4. The WTRU may identify the first cell and a transmitting beam index (e.g., a beam index and / or a Tx-beam) transmitting the pre-sync signal through one or more of the physical properties of the signal (e.g., time, frequency, sequence selection, phase, sequence ID, etc.). The WTRU may receive and decode an SSB / SIB-1 from a second (e.g., macro) cell, for example, if at least one of the following is met: the pre-sync received power from the first cell is greater than a first threshold (e.g., pre- sync-ReceivedPower from 1 cell > Threshol d 1 ); a full SSB is not received from the first cell or the first cell is determined to be in an NES state; and / or an RSRP from the second cell is less than a second threshold (e.g., Threshold 2).

[0217] As illustrated in FIG. 4, the WTRU may determine the PRACH configuration for the first cell, for example, based upon the received SIB-1 of the second cell and a detected (e.g., received) pre-sync sequence of the first cell, which may include, for example, one or more of the following: the system timing of the first cell, and the cell ID; association of the first cell Tx-Beam to RACH occasions (ROs) of the first cell; partition of RACH preambles associated with accessing the first cell; and / or association of first cell SSBs to first cell ROs, e.g., for preamble re-transmission on the first cell. The WTRU may determine the RO / preamble to use on the first cell, for example, based on the pre-sync signal of the first cell, and / or the (e.g., configured) association between pre-sync and ROs received on the second cell. The WTRU may perform a RACH procedure as described herein on the first cell, e.g., using / with the determined parameters. The WTRU may monitor an RA response on the first cell. The WTRU may monitor for SSB reception from the first cell, e.g., while the RAR window is running. The WTRU may transmit another preamble to the first cell, for example, if an RAR is not received on the first cell and the WTRU receives one or more SSBs from the first cell. The WTRU may determine the RO to use for the preamble transmission on the first cell, for example, based on a (e.g., the best) measured SSB on the first cell. The WTRU may transmit a preamble on the second cell, for example, if an RAR is not received on the first cell, e.g., after N attempts (e.g., N>=1). The WTRU may continue the RACH procedure on the second cell (e.g.,by transmitting MSG3 using the grant indicated in the RAR payload or by re-transmitting the preamble on the second cell), for example, if the WTRU receives a fallback indication in an RAR from the first cell (e.g., backoff indicator or a bit in the RAR payload.

[0218] A WTRU may perform initial access using multiple (e.g., two (2)) random access procedures. A WTRU may perform initial access in multiple steps, e.g., with an intended outcome to connect to a cell in an NES state, which may be the cell measured with the best channel conditions (e.g., based on one or more discovery signal measurements). A WTRU may (e.g., in a first step) perform an RA to the non-best measured cell (e.g., the second best measured cell). The WTRU may indicate the best measured cell part of the PUSCH payload of msg3 or msg A. The WTRU may (e.g., upon successful completion of the RA on the non-best measured cell) start measuring an SSB and / or receive an SSB on the indicated cell in the PUSCH payload (e.g., best measured cell).

[0219] One or more WTRU actions, e.g., as described herein and / or as illustrated in FIG. 4, may use one or more (e.g., any or all) of the actions described herein (e.g., previously) and in any order. A WTRU may detect (e.g., receive) a pre-sync (e.g., discovery) signal (e.g., PSS+SSS signal) from a first cell. A WTRU may identify the first cell transmitting the pre-sync signal, e.g., through one or more of the physical properties of the signal, such as time, frequency, sequence selection, phase, sequence ID, etc. A WTRU may receive and decode SSB / SIB-1 from a second cell.

[0220] A WTRU may determine the PRACH parameters, for example, based on the received SIB-1 from the second cell. A WTRU may (e.g., determine to) perform a RACH procedure on the second cell, for example, if at least one of the following is met: pre-sync Received Power from first cell > Threshold 1 ; a full SSB is not received from the first cell; the first cell is determined to be in an NES state;RSRP_from_second cell > Threshold 2. Threshold 1 and Threshold 2 may be the configuration parameters received from the network or otherwise indicated to or determined by (e.g., (pre)defined to) the WTRU.

[0221] A WTRU may perform a RACH procedure (e.g., as described herein), e.g., with determined parameters, on the second cell. A WTRU may provide the indication of the detected first cell, for example, through (MsgA / Msg3). The indication may include, for example, the cell identity, beam index, and / or information related to the WTRU detected pre-sync of the first cell.

[0222] A WTRU may receive the cell index, on which the WTRU may perform a second random access, for example, along with RACH configuration (e.g., SI or a new SIB) for the first cell from the second cell response to the WTRU’s transmitted RACH in MsgB / Msg4, or in a PDSCH after RACH. The configuration may include, for example, one or more of the following: dedicated preamble(s), second cell SSB to RO mapping on the first cell, one or more SSBs, and / or an RO to use for PRACH transmission on the first cell.

[0223] A WTRU may monitor an SSB on the first cell (e.g., on-demand SSB), for example, based on / upon successful completion of a RACH on a second cell and if WTRU has not received a RACH configuration for the first cell.

[0224] A WTRU may perform a second RACH procedure by transmitting a RACH preamble (e.g., Msg 1 or Msg A), for example, with determined parameters on the first cell, e.g., by selecting the indicated RO / SSB.

[0225] Beam failure avoidance and detection may be performed in energy saving networks (ESNs). A WTRU may receive a configuration to monitor one or more NES Cells. A WTRU may be configured with a set of NES cells to monitor, for example, if / when: an indication, such as a Beam Failure Avoidance flag, is configured on the serving cell; the serving cell is associated with at least one NES / non-stable cell; and / or BFD is configured on the serving cell. A WTRU may measure one or more channel conditions associated with the discovery or pre-synch signal associated with an NES cell (e.g., if / when a non-serving NES cell is monitored). The BFD configuration of the serving cell may include a list of candidate cells (e.g., NES cells or cells associated with the RefPCell) to monitor, for example, based on / upon meeting at least one condition used to determine if / when a WTRU monitors NES Cells (e.g., as described herein).

[0226] In some examples, a WTRU may be connected to a serving cell (e.g., a stable cell), which may be referred to as a “second cell.” The WTRU may monitor one or more additional NES cells, which may be referred to as a “first cell.” A WTRU may be connected to the second cell. The WTRU may have already received an SSB and / or other system information, such as SIB-1 and / or other SIBs. A WTRU may be configured (e.g., by the second cell) with a set of NES cells to monitor. A WTRU may receive the configuration to monitor one or more NES cells, for example, as part of a Beam Failure Avoidance procedure on the second cell. A WTRU may be configured with (e.g., suitable) RSs to monitor for at least one of the beams on the second cell.

[0227] A WTRU may be configured with one or more conditions indicating if / when the WTRU is expected to monitor the NES cells. The configured condition(s) may be based upon the measurements on the reference signals of the second cell. In some examples, conditions may be based upon the beam failure instances of the beam that the WTRU is connected to on the second cell.

[0228] A WTRU may (e.g., determine to) monitor one or more NES cells. A WTRU may determine to monitor the configured NES cells. The NES cells may be configured, for example, as part of beam failure avoidance or a BFD procedure on the second cell.

[0229] A WTRU may (e.g., determine to) monitor the configured NES cells, for example, based on one or more monitoring conditions, which may be specified with the configuration. The one or more conditionsmay include one or more of the following: the WTRU receiving N BFI for the second cell within a time T; the WTRU’s BFD_counter on the second cell > Threshold3A; measured channel conditions on the second cell (e.g., RSRP) < Threshold 2; reception of a DL indication from the network (e.g., a MAC CE, an indication by DCI, broadcast signaling, and / or RRC (re)configuration); reception of a CHO configuration or command (e.g., a CHO configuration associated with the serving cell going into NES state), which may be conditioned on having the NES cell listed as a CHO candidate in the CHO configuration.

[0230] A WTRU may (e.g., determine to) monitor the configured NES cells, for example, based on WTRU receiving N BFI for the second cell within a time T. T may be configured or determined based on the BFD timer value. N may be configured to be greater than or equal to one (1). T may be optionally configured. T may not be applied, for example, if not configured.

[0231] A WTRU may (e.g., determine to) monitor the configured NES cells, for example, based on reception of a DL indication from the network (e.g., a MAC CE, an indication by DCI, broadcast signaling, and / or RRC (re)configuration). In some examples, a WTRU may start monitoring an NES cell based on / upon reception of an RRC (re)configuration that includes the cell (e.g., part of the BFD cells to monitor list) or upon reception of an indication from the second cell indicating the NES state of the NES cells. In some examples, a WTRU may start monitoring an NES cell if it is indicated in (e.g., as part of) an L1 / 2 mobility command.

[0232] A WTRU may (e.g., determine to) monitor the configured NES cells, for example, based on reception of a CHO configuration or command (e.g., a CHO configuration associated with the serving cell going into an NES state), which may be conditioned on having the NES cell listed as a CHO candidate in the CHO configuration. The CHO configuration may include a separate measurement condition associated with a given cell if the cell is in an active NES state (e.g., a different measurement object or signal). For example, the CHO configuration may provide / indicate the pre-synch signal to measure for the associated CHO condition(s).

[0233] As described herein, N, T, Threshold 2, Threshold 3A, and / or the like may be configuration parameters. A WTRU may receive and / or determine NES cell parameters from pre-sync signals. A WTRU may detect (e.g., receive) a pre-sync signal from a first cell, e.g., an NES cell. A WTRU may be configured to detect (e.g., receive) one or more pre-sync signals as part of an initial access procedure. A pre-sync signal may be, for example, a discovery signal, an SSB signal, a slim version of an SSB signal (e.g., PSS, SSS, or PSS+SSS). The periodicity of the pre-synch signal may be (pre)defined or (pre)configured, for example, per frequency band, carrier, and / or BWP. A WTRU may acquire a pre-synch signal configuration(e.g., including the periodicity), for example, from an associated Ref-PCell, anchor carrier, and / or stable cell. The associated cell may provide the configuration part of its broadcast or dedicated signaling.

[0234] A WTRU may determine to process / monitor (e.g., further) a pre-sync signal received from a first cell, for example, if the pre-sync-ReceivedPower is large than a first threshold, e.g., based on measured channel conditions associated with the cell’s pre-synch signal. A WTRU may be configured or predefined with a measurement filtering window to apply, for example, in order to determine the channel measurement associated with the first cell. The threshold may be known to a WTRU through pre-configuration. A WTRU may be (pre)defined with the threshold. In some examples, a WTRU may receive the threshold from the network (e.g., in one of its last connections to the network) and / or from configurations provided from an associated Ref-PCell.

[0235] A WTRU may determine the cell identity, e.g., PCI, of the first cell from the received pre-sync signal of the first cell. A WTRU may determine a beam-index associated with a received pre-sync signal of the first cell. A WTRU may determine a cell ID and / or beam index associated with a pre-sync signal, for example, through one or more physical properties of the signal (e.g., time, frequency, sequence selection, phase, sequence ID, etc).

[0236] A WTRU may (e.g., determine to) report NES cell measurements. A WTRU may (e.g., determine to) report the measurements made over the signals of the configured NES cells and / or report a beam failure avoidance to the serving cell (e.g., the second cell), for example, if one or more the following conditions are met: pre-sync or discovery signal-ReceivedPower from first cell (e.g., a candidate nonserving NES cell) measured channel condition is greater than a first threshold (Threshold 1); a full SSB is not detected / received from first cell and / or the first cell is determined to be in an NES state; one or more measured channel conditions (e.g., RSRP) of the second cell is / are greater than a threshold (e.g., Threshold 2a) and / or less than a threshold (e.g., Threshold 2B); a BFD counter on the second cell is greater than a threshold (e.g., Threshold 3B); a beam failure has been detected on the second cell; and / or beam(s) configured as part of the BFR_candidate_set (e.g., all beams in the set) are measured less than a threshold (e.g., Threshold 4).

[0237] As described herein, Threshold 1 , Threshold 2A, Threshold 2B, Threshold 3B, and Threshold 4 may be configuration parameters.

[0238] In some examples, a WTRU may make measurements over other detected cells (e.g., NES cells), even if not configured as part of the beam failure avoidance procedure or the list of NES cells in the BFD configuration of the second cell.

[0239] A WTRU may report the NES Cells. A WTRU may report the identity of the detected configured NES cell and the measurements on the detected cell to the second cell. A WTRU may (e.g., upon satisfying at least one of the triggers to report NES cells, as described herein) trigger the report by multiplexing a beam failure avoidance MAC CE, e.g., if an uplink grant is available. A WTRU may (e.g., determine to) transmit the report as part of beam failure avoidance MAC or an RRC message, e.g., if the WTRU has a UL grant available to transmit on the second cell. The WTRU may report the MAC CE (e.g., only), for example, after measuring at least one cell other than the second cell (e.g., an NES cell or a nonstable cell) with a channel condition measurement above a configured threshold.

[0240] The beam failure avoidance MAC CE (e.g., or RRC report, as used interchangeably herein) may include at least one of the following: the cell index of the cell for which the channel measurement was made above a threshold or from which a discovery or a pre-synch signal was detected; the logical channel (LCH) index corresponding to the failure reporting or the LCH associated with failure reporting; the BWP index of the BWP on which beam failure was detected; channel condition measurements of other detected cells (e.g., non-stable cells or NES cells), which may include RSRP, SINR, RSSI, etc.; and / or an index or indices of preferred beams, e.g., a beam that best meets (pre)configured or (pre)defined criteria, which may include RSRP, SINR, RSSI, and / or channel occupancy.

[0241] The measurements on the detected cell may include, for example, the signal strength of the presync signal. In some examples, the measurements may include the RSRP of the RS transmitted as part of pre-sync signal.

[0242] A WTRU may transmit an SR or an RA on the second cell to report beam failure avoidance. A WTRU may transmit an SR corresponding to the SR configuration configured to report beam failure avoidance. The WTRU may trigger a new SR or an RA-SR if / when it doesn’t have a (e.g., suitable) UL resource available for transmission of the failure avoidance MAC CE. Suitability of available grants (e.g., for an SR triggered by failure avoidance) may be determined, for example, based on RRC configurations that determine grant suitability or based on the LCH assigned to the SR triggered by failure reporting. For example, a WTRU may be configured by RRC with one or more (e.g., certain) grant characteristics that deem a (e.g., certain) grant as suitable for transmission of a failure avoidance MAC for a (e.g., certain) serving cell.

[0243] In some examples, a WTRU may be statically or semi-statically configured with a priority, LCH, SR configuration(s), and / or PUCCH resource for SRs triggered by the failure avoidance reporting procedure. In some examples, an RRC may configure a WTRU with an (e.g., a certain) SR configuration(s) (e.g., or, more generally, a set of PUCCH resources) to be used for an SR triggered by the failure reportingprocedure. In some examples, a WTRU may be configured by RRC with an SR configuration per cell, BWP, or subband. In some examples, a WTRU may use a (e.g., any) PUCCH resource configured on the cell for reporting an SR triggered by failure avoidance reporting. In some examples (e.g., in such a case), an SR triggered by failure reporting may have a (e.g., specific) priority (e.g., highest priority) compared to other SRs, HARQ / ACK feedback, and / or CSI reports that may be included in the PUCCH resource. In some examples, the priority of the SR triggered by failure reporting may be configurable.

[0244] A WTRU may be configured with a static priority or a (e.g., certain) LCH, which the WTRU may use for determining which SR configuration to use and / or determine the priority of the SR, e.g., among other possible uses. For example, an RRC may configure a WTRU with an (e.g., a certain) LCH to be associated with an SR triggered by a failure reporting, and / or the cell on which beam failure was detected. The WTRU may associate a priority with a (e.g., certain) recovery SR, e.g., when priority overlaps with other UCI, PUSCH, or other transmission and / or actions related to intra-WTRU prioritization may (e.g., need to be) performed.

[0245] A WTRU may monitor for PDCCH on a second cell, e.g., following an SR or MAC CE failure avoidance transmission. A WTRU may monitor PDCCH on a second cell index or another cell (e.g., the indicated cell in the MAC CE), for example, after reception of a full SSB from the indicated cell (e.g., the first cell). A WTRU may cancel an SR triggered by failure avoidance reporting and / or, more generally, consider a failure avoidance procedure to be successfully completed after one or more of the following: transmission of a failure reporting MAC CE, reception of a response from the gNB (e.g., PDCCH) from the second cell or the first cell, reception of an uplink grant, reception of an SSB (e.g., full SSB) from an indicated cell (e.g., the first cell), and / or reception of network re-configuration of parameters related to the indicated cell or the second cell (e.g., an RRC message).

[0246] A WTRU may receive an indication to perform RACH on an NES Cell. A WTRU may receive an indication from the second cell to perform RACH on an NES cell, for example, after transmission of a failure avoidance report. In some examples, a WTRU may receive an indication to perform RACH on the NES cell for which it reported identity and / or configured measurements to the second cell and / or the WTRU may receive an indication to start monitoring for SSBs on an indicated different cell (e.g., the first cell), e.g., along with synchronization timing parameters.

[0247] In some examples, a WTRU may receive an indication to perform RACH on an NES cell different from the cell reported by the WTRU (e.g., another NES cell selected by the network).

[0248] A WTRU may receive an indication to perform RACH on an NES cell through a PDCCH order, through MAC signaling, or in an RRC message. The WTRU may be provided with dedicated preamblesand / or RACH configurations associated with the indicated NES cell. The information (e.g., indication to perform RACH, dedicated preambles, RACH configuration(s)) may be received from the second cell.

[0249] A WTRU may perform a RACH transmission on the NES cell. A WTRU may transmit RACH on the first cell or another indicated cell (e.g., in response to the failure avoidance report), for example, upon receiving an indication to perform RACH on the first cell received from the second cell.

[0250] A WTRU may monitor one or more SSBs on the first cell and / or another indicated cell (e.g., in response to the failure avoidance report), for example, if the WTRU receives an indication from the second cell (e.g., in a MAC CE or DCI, or HARQ feedback for a transport block (TB) on which the MAC CE was multiplexed).

[0251] A WTRU may determine the RACH configuration and / or initial access parameters for the first cell, for example, based on one or more of the following. A WTRU may monitor one or more SSBs on the first cell, for example, if the WTRU receives an indication from the second cell (e.g., in a MAC CE or DCI, or HARQ feedback for the TB on which the MAC CE was multiplexed). A WTRU may perform an RA on the first cell (e.g., by transmitting a preamble using the received SIB1 configuration parameters), for example, if SSB and / or SIB-1 are received on the first cell (e.g., a full SSB with PBCH). A WTRU may perform an RA on the first cell (e.g., by transmitting a preamble using the SSB to RO association received from the second cell SIB-1), for example, if the SSB is received without SIB-1 on the first cell. The response to the failure avoidance report from the second cell may include an association of SSB to RO applicable to the first cell. The SSBs may be those of the first cell and / or the second cell. A WTRU may perform handover (e.g., reconfiguration with synchronization) to the first cell, for example, based on / upon receiving an indication from first cell (e.g., in Msg B or Msg2 / 4) and / or upon satisfying one or more CHO conditions (e.g., CHO conditions based on channel measurements associated with the first and / or second cell, based on the first cell changing NES states, and / or based on reception of NES-associated CHO configuration associated with the first and / or second cell).

[0252] A cross-cell BFD / RLM procedure may combine the BFD / RLM signals (such as SSBs and / or CSI- RS) from more than one cell, e.g., the reference P-Cell and another supplementary NES cell or a nonstable cell. The WTRU may be configured with an association between cells (e.g., an association between a stable cell and a non-stable cell, an association between an NES cell and a non-NES cell, and / or an association between a reference Pcell and a secondary cell). An association may be used to perform cross cell BFD measurements.

[0253] A WTRU may (e.g., in a cross-cell BFD) maintain separate or joint BFD / RLM parameters (e.g., counters and timers). A BFI may be generated, for example, if either cell generates a BFI or if both cellsgenerate a BFI. A WTRU may increment the BFI counter differently, for example, depending on the cell from which the BFI was received from. The WTRU may be configured with multiple (e.g., two) BFD counters / thresholds, such as a first counter for cell reference Pcell, and a second counter for a non-anchor NES cell. Different counters and thresholds may be used to determine a BFD procedure.

[0254] A WTRU may monitor BFD reference signals and / or SSBs from a different cell (e.g., the anchor cell or the reference PCell) for a given non-anchor NES cell.

[0255] A WTRU may be configured or predefined with one or more (e.g., certain) preconditions for when the WTRU combines BFD measurements for an NES cell with another cell (e.g., an Ref-PCell or an anchor cell), including at least one of the following preconditions: the cells are geolocated, the cells are correlated from an RF perspective (e.g., whereby a measurement offset can be added to be applicable to a non-Ref- PCell), cells are configured with common beam management, and / or cells belong to the same CU node or scheduler.

[0256] Pre-sync or discovery signals transmitted from an NES cell (e.g., a non-stable cell, a non-anchor cell, and / or a cell associated with a P-Ref cell) may be used for BFD measurements for the cell, which may be combined with other signals (e.g., BFD RS or SSB signals) received from another associated cell. In some examples, a WTRU may reset the BFD counter and / or stop the BFD timer for a given NES cell if the received discovery signal channel condition measurement is above a (e.g., certain) threshold (e.g., a threshold associated with Qin BFD, a measured SINR, measured RSRP, or a measured BLER)., the WTRU may increment a BFD counter with a larger step compared to other reference signals configured for BFD (e.g., those received from an anchor cell or an associated P-Ref cell or an associated stable cell), for example, if a discovery signal is measured below a threshold.

[0257] As described herein, a WTRU may perform beam failure avoidance by waking up an NES cell. A WTRU may be connected to the second cell. The WTRU may monitor configured BFD signals (e.g., already successfully completed RA on the second cell). The WTRU may be configured with a set of NES cells to monitor, for example, if / when Beam Failure Avoidance is configured on the second cell. The WTRU may start monitoring NES cells for beam failure avoidance on the second cell, for example, if a BFD_counter on the second cell is greater than a third threshold (Threshold3A) and / or the second cell RSRP is less than a second threshold (Threshold 2A). The WTRU may detect / receive a pre-sync (e.g., discovery), such as a PSS+SSS signal from a first cell (e.g., NES cell). The WTRU may identify the first cell transmitting this pre-sync signal through one or more of the physical properties of the pre-sync signal (e.g., time, frequency, sequence, phase, etc.). The WTRU may determine to send a beam failure avoidance report (e.g., to the second cell), for example, if at least one of the following is met: pre-sync-ReceivedPowerfrom first cell is greater than a first threshold (Threshold 1); a full SSB is not received from the first cell or the first cell is determined to be in an NES state; an RSRP from the second cell (RSRP_from_second cell) is greater than a second threshold (Threshold 2B); a beam failure detection (BFD) counter on the second cell is greater than a third threshold (Threshold 3B); and / or the BFR candidate(s) in a BFR_candidate_set on the second cell is / are (e.g., all) measured less than a threshold. The WTRU may transmit a beam failure avoidance report (e.g., MAC CE) on the second cell, for example, if an uplink (UL) grant is available. The WTRU may transmit an SR on the second cell to report a beam failure avoidance, for example, if otherwise (e.g., if the UL grant is not available). A beam failure avoidance report (e.g., MAC CE) may provide an indication of the first cell physical cell identity (PCI), e.g., along with measured pre-sync signal strength. A WTRU may be configured with an SR configuration for reporting beam failure avoidance. The WTRU may receive an indication from the second cell indicating whether to perform RA on a cell different from the second cell (e.g., on the first cell). The WTRU may perform one or more of the following, for example, if the WTRU receives an indication to perform an RA on the first cell. The WTRU may monitor one or more SSBs on the first cell, for example, if the WTRU receives an indication from the second cell that the first cell is or will be activated. The WTRU may perform an RA on the first cell (e.g., by transmitting a preamble using the received SIB1 configuration), for example, if an SSB and SIB-1 are received on the first cell. The WTRU may perform an RA on the first cell (e.g., by transmitting a preamble using an SSB to RO association received from the second cell SIB-1), for example, if SSB is received without an SIB-1 on the first cell.

[0258] 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.

[0259] 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.

[0260] The processes described above 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 suchas 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 WTRLI, terminal, base station, RNC, and / or any host computer.

Claims

Claims1 . A wireless transmit / receive unit (WTRU) comprising: a processor configured to: receive a pre-synchronization (pre-sync) signal; determine a first cell transmitting the pre-sync signal and a transmitting beam index associated with the pre-sync signal based on a property of the pre-sync signal; determine whether a condition is satisfied, wherein the condition is satisfied based on at least one of a determination that a received power associated with the pre-sync signal is greater than a threshold, a determination that a full synchronization signal block (SSB) is not received from the first cell, or a determination the first cell is in an energy savings state; based on a determination that the condition is satisfied, receive a transmission from a second cell; determine a random access channel (RACH) configuration for the first cell based on the transmission from the second cell and the pre-sync signal, wherein the RACH configuration comprises an association of the pre-sync signal to at least one physical RACH occasion (RO) associated with the first cell, wherein the pre-sync signal is associated with the first cell; determine an RO that is associated with the first cell and a preamble based on the presync signal and the RACH configuration for the first cell; and transmit the preamble on the RO that is associated with the first cell.

2. The WTRU of claim 1 , wherein the pre-sync signal comprises at least one of a discovery signal, an SSB signal, a primary synchronization signal (PSS), a secondary synchronization signal (SSS), or a combination of PSS and an SSS, wherein the SSB signal is not a full SSB signal,.

3. The WTRU of claim 1 , wherein the property associated with the pre-sync signal comprises at least one of a time, a frequency, a sequence selection, a phase, a sequence identification (ID) associated with the pre-sync signal.

4. The WTRU of claim 1 , wherein the transmission from the second cell comprises at least one of an SSB or a system information block (SIB).

5. The WTRU of claim 1 , wherein the transmission is associated with at least one SSB from the second cell, wherein the processor is further configured to:determine to receive the at least one SSB via the second cell based on at least one of: a same frequency that the pre-sync signal and the at least one SSB are received, a different frequency that the presync signal and the at least one SSB are received, an indication associated with the pre-sync signal, or a parameter comprising at least one of: a time resource to receive the at least one SSB, a frequency resource to receive the at least one SSB, a carrier frequency associated with the at least one SSB, or a cell ID associated with the at least one SSB.

6. The WTRU of claim 1 , wherein the RACH configuration comprises at least one of: a system timing associated with the first cell and a first cell ID, an association of a transmitting beam (Tx beam) to the RO associated with the first cell, or a partition of RACH preambles with the RO or the TX beam associated with accessing the first cell.

7. The WTRU of claim 1 , wherein the processor is further configured to: monitor for a random access response (RAR) from the first cell during an RAR window; determine whether the RAR is received; and based on a determination that the RAR is received, determine a resource to transmit a message; and transmit the message on the resource.

8. The WTRU of claim 7, wherein the processor is configured to: determine whether a fallback indication is received in the RAR on the first cell; and based on a determination that the fallback indication is received, perform a RACH procedure on the second cell.

9. The WTRU of claim 1 , wherein the preamble is a first preamble, and wherein the processor is configured to: monitor for an RAR from the first cell during an RAR window; determine whether the RAR is received; based on a determination that the RAR is not received on the first cell, determine that at least one SSB is received from the first cell; and based on the determination that the at least one SSB is received from the first cell, transmit a second preamble on the RO that is associated with the first cell, wherein the RO used for the second preamble transmission is determined further based on a measured SSB associated with the first cell.

10. The WTRU of claim 9, wherein the threshold is a first threshold, and wherein the processor is configured to: based on a determination that the RAR is not received on the first cell, determine whether a number of retransmissions of the preamble is above a second threshold; and based on a determination that the number of retransmissions of the preamble is above the second threshold, transmit the preamble on the second cell.11 . The WTRU of claim 1 , wherein the threshold is a first threshold, and wherein the processor is configured to: determine that a reference signal receive power (RSRP) associated with the second cell is below a second threshold; and based on the determination that the RSRP is below the second threshold, perform a RACH transmission on the first cell.

12. A method comprising: receiving a pre-synchronization (pre-sync) signal; determining a first cell transmitting the pre-sync signal and a transmitting beam index associated with the pre-sync signal based on a property of the pre-sync signal; determining whether a condition is satisfied, wherein the condition is satisfied based on at least one of a determination that a received power associated with the pre-sync signal is greater than a threshold, a determination that a full synchronization signal block (SSB) is not received from the first cell, or a determination the first cell is in an energy savings state; based on a determination that the condition is satisfied, receiving a transmission from a second cell; determining a random access channel (RACH) configuration for the first cell based on the transmission from the second cell and the pre-sync signal, wherein the RACH configuration comprises an association of the pre-sync signal to at least one physical RACH occasion (RO) associated with the first cell, wherein the pre-sync signal is associated with the first cell; determining an RO that is associated with the first cell and a preamble based on the pre-sync signal and the RACH configuration for the first cell; and transmitting the preamble on the RO associated with the first cell.

13. The method of claim 12, wherein the pre-sync signal comprises at least one of: a discovery signal, an SSB signal, a primary synchronization signal (PSS), a secondary synchronization signal (SSS), or a combination of PSS and an SSS, and wherein the SSB signal is not a full SSB signal.

14. The method of claim 12, wherein the property associated with the pre-sync signal comprises at least one of: a time, a frequency, a sequence selection, a phase, a sequence identification (ID) associated with the pre-sync signal, and wherein the transmission from the second cell comprises at least one of an SSB or a system information block (SIB).

15. The method of claim 12, wherein the transmission is associated with at least one SSB from the second cell, and wherein the method further comprises: determining to receive the at least one SSB via the second cell based on at least one of: a same frequency that the pre-sync signal and the at least one SSB are received, a different frequency that the presync signal and the at least one SSB received, an indication associated with the pre-sync signal, or a parameter comprising at least one of a time resource to receive the at least one SSB, a frequency resource to receive the at least one SSB, a carrier frequency associated with the at least one SSB, or a cell ID associated with the at least one SSB.

16. The method of claim 12, wherein the RACH configuration comprises at least one of: a system timing associated with the first cell and a first cell ID, an association of a transmitting beam (Tx beam) to the RO associated with the first cell, or a partition of RACH preambles with the RO or the TX beam associated with accessing the first cell.

17. The method of claim 12, wherein the method further comprises: monitoring for a random access response (RAR) from the first cell during an RAR window; determining whether the RAR is received; and based on a determination that the RAR is received, determining a resource to transmit a message; and transmitting the message on the resource.

18. The method of claim 17, wherein the method comprises: determining whether a fallback indication is received in the RAR on the first cell; andbased on a determination that the fallback indication is received, perform a RACH procedure on the second cell.

19. The method of claim 12, wherein the preamble is a first preamble and wherein the method comprises monitor for an RAR from the first cell during an RAR window; determine whether the RAR is received; based on a determination that the RAR is not received on the first cell, determining that at least one SSB is received from the first cell; and based on the determination that the SSB is received from the first cell, transmitting a second preamble on the RO that is associated with the first cell, wherein the RO used for the second preamble transmission is determined further based on a measured SSB associated with the first cell.

20. The method of claim 19, wherein the threshold is a first threshold, and wherein the method comprises: based on a determination that the RAR is not received on the first cell, determining whether a number of retransmissions of the preamble is above a second threshold; and based on a determination that the number of retransmissions of the preamble is above the second threshold, transmitting the preamble on the second cell.

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