Methods for Layer 1 / 2 Trigger Mobility (LTM) with Network Energy Saving (NES)

Abstract

A WTRU can receive configuration information for one or more NES states. The NES state cell off can be configured to indicate that a cell can be turned off for a duration. Based on the WTRU location, the network can configure the WTRU with a set of candidate neighbor cells for L1 / 2 triggered mobility (LTM). The network can send an L1 / 2 signaling message indicating the activation of NES state cell off for a subset of the configured candidate neighbor cells. The above indication can be sent to a group of WTRUs in a cell or to all WTRUs. The WTRU can trigger LTM-related measurements in candidate neighbor cells that are not in NES state cell off. The above measurements can be reported to the network using an L1 / 2 signaling message. Based on the received measurement reports, the network can then send an L1 / 2 signaling message indicating that the WTRU is switching to a target cell.

Description

Background Art

[0001] Cross - reference to related applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 457,059, filed on April 4, 2023, the content of which is incorporated herein by reference.

[0002] LTM can involve the use of L1 / 2 lower layer signaling for handover - related procedures such as measurement reports. This can involve using MAC control elements (CEs) instead of using L3 RRC messages. For example, instead of a base station sending an RRC reconfiguration message to a WTRU (Wireless Transmit / Receive Unit), it can send a MAC - CE instead. In one example, a WTRU can be configured by one or more handover parameters such as different candidate cells for handover, and the base station can send a MAC - CE to the WTRU indicating which configuration should be used for handover. Further, the base station determination for triggering a handover can be based on layer 1 measurements such as CSI - RS instead of relying on an RRC measurement report message.

[0003] Network energy saving (NES), which indicates the base station power saving status, can be associated with a cell. A cell in the NES state cell - off can indicate that the cell is off, for example, that the baseband hardware of the base station is completely off. A cell in an active NES state can indicate that the cell is operating normally. A WTRU can determine whether it can transmit or receive in a cell based on the NES state of the cell.

Summary of the Invention

Means for Solving the Problems

[0004] Systems, methods, and / or devices may take network energy conservation into consideration when determining candidate cell selection management during mobility events. A system may have a method for configuring devices with network energy conservation information, which can then be reported and switched later. There may also be system information blocks and / or group-common indications for conditional network energy conservation cell switching. [Brief explanation of the drawing]

[0005] A more detailed understanding can be obtained from the following explanation, which is given as an example in conjunction with the attached drawings, where similar reference numbers in the drawings indicate similar elements.

[0006] [Figure 1A] This is a system diagram showing an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) used in the communication system shown in Figure 1A, using one or more techniques disclosed herein. [Figure 1C] This is a system diagram showing exemplary radio access network (RAN) and core network (CN) used in the communication system of Figure 1A, using one or more techniques disclosed herein. [Figure 1D] This is a system diagram showing further exemplary RAN and CN used in the communication system of Figure 1A by one or more techniques disclosed herein. [Figure 2] This figure shows an example of a measurement model. [Figure 3] This figure shows an example of LTM operation using carrier aggregation (CA). [Figure 4] This figure shows an example of the LTM baseline procedure. [Figure 5]This figure shows an example of an LTM configuration update based on a common indication that updates the NES status of a cell. [Figure 6] This figure shows an example of the interaction between the NES state and LTM operation. [Figure 7] This figure shows an example of dedicated and dynamic indication for enabling / disabling different LTM neighbors based on the NES state. [Figure 8] This figure shows an example where a cell switching command includes an indication of the NES state for the cell sending the cell switching command. [Figure 9] This is a flowchart illustrating an example of the WTRU LTM procedure while the WTRU receives common signaling with NES indication. [Figure 10] This is an example flowchart of group-wide NES indication and WTRU reporting when SpCell enters NES state cell-off mode. [Figure 11] This is a flowchart illustrating an example of LTM update using SIB-based NES indication. [Figure 12] This is a flowchart illustrating an example of LTM updates using SIB-based NES indication and conditional LTM. [Modes for carrying out the invention]

[0007] Table 1 below lists one or more acronyms that may be used herein.

[0008] [Table 1-1]

[0009] [Table 1-2]

[0010] [Table 1-3]

[0011] FIG. 1A is a system diagram showing an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-connection system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 can enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail (ZT: zero-tail) unique word (UW: unique-word) discrete Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC: filter bank multicarrier).

[0012] As shown in FIG. 1A, communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it is understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d may each be referred to as a “station” and / or “STA” and may be configured to transmit and / or receive wireless signals and may be a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a wristwatch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., remote surgery), an industrial device and application (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), a home electronic device, a device operating on a commercial and / or industrial wireless network, etc. (or be any of these). Any of the WTRUs 102a, 102b, 102c, and 102d may also be referred to interchangeably as a UE.

[0013] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106, the Internet 110, and / or network 112. As an example, base stations 114a and 114b may be any of the following: base station transceiver station (BTS), node B (NB), e-node B (eNB), home node B (HNB), home e-node B (HeNB), g-node B (gNB), NR node B (NR NB), site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are shown as single elements, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0014] Base station 114a may be part of RAN 104, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, sometimes called cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell can provide coverage for radio services to a specific geographic area that may be relatively fixed or change over time. A cell may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology, and multiple transceivers may be available for each sector of the cell or any sector. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0015] Base stations 114a and 114b can communicate with one or more WTRUs 102a, 102b, 102c, and 102d via an air interface 116, the air interface 116 may be any suitable radio 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).

[0016] More specifically, as described above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can establish an air interface 116 using broadband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Advanced HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0017] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c can implement radio technologies such as Advanced UMTS Terrestrial Radio Access (E-UTRA), which can establish an air interface 116 using Long-Term Evolution (LTE) and / or LTE Advanced (LTE-A) and / or LTE Advanced Pro (LTE-A Pro).

[0018] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c can implement radio technologies such as NR radio access, which can establish an air interface 116 using New Radio (NR).

[0019] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base stations 114a and WTRUs 102a, 102b, and 102c can implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Thus, the air interface utilized by WTRUs 102a, 102b, and 102c may be characterized by multiple types of radio access technologies and / or transmissions from / to multiple types of base stations (e.g., eNBs and gNBs).

[0020] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c can implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (Wi-Fi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Advanced Data Rate (EDGE), and GSM EDGE (GERAN).

[0021] In Figure 1A, base station 114b may be, for example, a wireless router, home node B, home enode B, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in localized areas such as offices, homes, vehicles, premises, industrial facilities, aerial corridors (for use by drones, for example), and roads. In one embodiment, base station 114b and WTRU 102c, 102d can implement wireless technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, base station 114b and WTRU 102c, 102d can implement wireless technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In one embodiment, base station 114b and WTRU 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish any small cell, picocell, or femtocell. As shown in Figure 1A, base station 114b may have a direct connection to the internet 110. Therefore, base station 114b may not be required to access the internet 110 via CN 106.

[0022] RAN104 may communicate with CN106, 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 WTRU102a, 102b, 102c, and 102d. The data may have various Quality of Service (QoS) requirements, including different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN106 may provide call control, billing services, mobile location-based services, prepaid calling, internet connectivity, video distribution, and / or implement high-level security features, such as user authentication. Although not shown in Figure 1A, it will be understood that RAN104 and / or CN106 may communicate directly or indirectly with other RANs employing the same RAT as RAN104 or different RATs. For example, in addition to being connected to RAN104, which may utilize NR radio technology, CN106 may also communicate with another RAN (not shown) employing one of the following technologies: GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or Wi-Fi radio technology.

[0023] CN106 can also act as a gateway for WTRU102a, 102b, 102c, and 102d to access PSTN108, the Internet 110, and / or other networks 112. PSTN108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as TCP, User Datagram Protocol (UDP), and / or IP in the Transmission Control Protocol / Internet Protocol (TCP / IP) Internet Protocol Suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may employ the same RAT as RAN104 or a different RAT.

[0024] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 can include multimode capability (for example, WTRUs 102a, 102b, 102c, and 102d can include multiple transceivers for communicating with different radio networks via different radio links). For example, WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a which can employ cellular-based radio technology and may be configured to communicate with base station 114b which can employ IEEE 802 radio technology.

[0025] Figure 1B is a system diagram showing an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 may include, in particular, a processor 118, a transceiver 120, a transceiver element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other elements / peripherals 138. It will be understood that the WTRU 102 may include any partial combination of the above elements while remaining consistent with one embodiment.

[0026] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 can 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 transceiver element 122. Although Figure 1B shows the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together, for example, in an electronic package or chip.

[0027] The transmitting / receiving element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmitting / receiving element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmitting / receiving element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In one embodiment, the transmitting / receiving element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmitting / receiving element 122 may be configured to transmit and / or receive any combination of radio signals.

[0028] Although the transmit / receive element 122 is shown as a single element in Figure 1B, the WTRU 102 can include any number of transmit / receive elements 122. For example, the WTRU 102 can employ MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving radio signals via the air interface 116.

[0029] The transceiver 120 may be configured to modulate the signal to be transmitted by the transmitting / receiving element 122 and to demodulate the signal received by the transmitting / receiving element 122. As described above, the WTRU 102 may have multimode capability. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0030] The processor 118 of the WTRU102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (for example, a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input data from them. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132, and store data therein. 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. Removable memory 132 may include a subscriber identification module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 can access information from memory not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data therein.

[0031] The processor 118 may be configured to receive power from the power supply 134 and distribute and / or control power to other components in the WTRU 102. The power supply 134 can be any suitable device for supplying power to the WTRU 102. For example, the power supply 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.), a solar cell, a fuel cell, etc.

[0032] The processor 118 may also be coupled to a 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 instead of, the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116 and / or determine its location based on the timing of when signals are received from two or more nearby base stations. It will be understood that the WTRU 102 may acquire location information via any preferred location determination method while remaining consistent with one embodiment.

[0033] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules / units that provide additional features, functionality and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), 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. Peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, a compass sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0034] WTRU102 may include a full-duplex radio where the transmission and reception of some or all of a signal may be parallel and / or simultaneous, associated with a specific subframe for both an uplink (for transmission, for example) and a downlink (for reception, for example). The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via signal processing either through hardware (e.g., chokes) or through a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU102 may include a half-duplex radio, which is for the transmission and reception of some or all of a signal (e.g., associated with a specific subframe for either an uplink (for transmission, for example) or a downlink (for reception, for example).

[0035] Figure 1C is a system diagram showing RAN104 and CN106 according to one embodiment. As described above, RAN104 can employ E-UTRA radio technology to communicate with WTRU102a, 102b, and 102c via the air interface 116. RAN104 may also communicate with CN106.

[0036] RAN104 may include enodes B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of enodes B while remaining consistent with one embodiment. Each of enodes B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, enodes B160a, 160b, and 160c can implement MIMO technology. Thus, enode B160a may, for example, use multiple antennas to transmit radio signals to and receive radio signals from WTRU102a.

[0037] Each of the e-nodes B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling on uplink (UL) and / or downlink (DL), etc. As shown in Figure 1C, the e-nodes B160a, 160b, and 160c can communicate with each other via the X2 interface.

[0038] The CN106 shown in Figure 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (PGW) 166. Although each of the above elements is shown as part of CN106, it will be understood that any one of these elements may be owned and / or operated by an entity other than the CN operator.

[0039] The MME162 can be connected to each of the e-nodes B160a, 160b, and 160c in RAN104 via the S1 interface and can act as a control node. For example, the MME162 can be responsible for authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting a specific serving gateway during the initial attachment of WTRU102a, 102b, and 102c. The MME162 can provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0040] The SGW164 can be connected to each of the e-nodes B160a, 160b, and 160c in RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions, such as anchoring the user plane during e-node B handovers, triggering paging when DL data is available for WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0041] SGW164 may be connected to PGW166, which can provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0042] CN106 can facilitate communication with other networks. For example, CN106 can provide WTRU102a, 102b, and 102c with access to circuit-switched networks such as PSTN108, thereby facilitating communication between WTRU102a, 102b, and 102c and legacy landline communication devices. For example, CN106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN106 and PSTN108. Furthermore, CN106 can provide WTRU102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0043] Although the WTRU is described as a wireless terminal in Figures 1A to 1D, in certain representative embodiments, such a terminal is intended to be able to use a wired communication interface with a communication network (for example, temporarily or permanently).

[0044] In a typical embodiment, the other network 112 may be a WLAN.

[0045] In Infrastructure Basic Service Set (BSS) mode, a WLAN may have access points (APs) for the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with distributed systems (DSs) or other types of wired / wireless networks that carry traffic during and / or from the BSS. Traffic originating outside the BSS to the STAs may arrive through the APs and be delivered to the STAs. Traffic originating from the STAs to destinations outside the BSS may be sent to the APs to be delivered to their respective destinations. Traffic between STAs within the BSS may be sent through the APs; for example, a source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS is considered and / or sometimes referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between a source STA and a destination STA (for example, directly between them) via a direct link setup (DLS). In some typical embodiments, the DLS may be an 802.11e DLS or an 802.11z tunnel DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have access points (APs), and STAs within or using IBSS (for example, all STAs) can communicate directly with each other. The IBSS communication mode is sometimes referred to as the “ad-hoc” communication mode in this specification.

[0046] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP can transmit beacons on a fixed channel, such as a primary channel. The primary channel can be a fixed width (e.g., a 20 MHz bandwidth) or a dynamically set width via signaling. The primary channel can be the operating channel of the BSS, which can be used by STAs to establish a connection with the AP. In some typical embodiments, Carrier sense multiple access with collision avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. In CSMA / CA, an STA, including the AP (e.g., any STA), can sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that STA can backoff. One STA (e.g., only one station) can transmit at any given time within a given BSS.

[0047] A high-throughput (HT) STA can use a 40MHz wide channel for communication, for example, via a combination of a primary 20MHz channel and adjacent or non-adjacent 20MHz channels to form a 40MHz wide channel.

[0048] Ultra-high throughput (VHT) STAs can support 20MHz, 40MHz, 80MHz, and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining consecutive 20MHz channels. 160MHz channels can be formed by combining eight consecutive 20MHz channels, or by combining two discontinuous 80MHz channels, sometimes referred to as an 80+80 configuration. In the 80+80 configuration, data can be passed through a segment parser that, after channel encoding, can split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time-domain processing can be performed separately for each stream. The streams can be mapped onto two 80MHz channels, and the data can be transmitted by a transmitting STA. At the receiver of a receiving STA, the operation described above for the 80+80 configuration can be reversed, and the combined data can be sent to a media access control (MAC) layer, entities, etc.

[0049] Sub-1GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV white space (TVWS) spectrum, while 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using the non-TVWS spectrum. According to a typical embodiment, 802.11ah can support meter-type control / machine-type communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have limited capabilities, including support for some and / or limited bandwidths (e.g., support only for that). MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0050] A WLAN system that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, includes a channel that can 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 the STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In the 802.11ah example, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) 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 detection and / or network allocation vector (NAV) settings may depend on the status of the primary channel. For example, if the primary channel is busy because an STA (which only supports 1MHz operating mode) is transmitting to the AP, the entire available frequency band may be considered busy, even though a large portion of the frequency band remains idle and could be available.

[0051] In the United States, the available frequency band that can be used by 802.11ah is from 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is from 6 MHz to 26 MHz, depending on the country code.

[0052] Figure 1D is a system diagram showing RAN104 and CN106 according to one embodiment. As described above, RAN104 can employ NR radio technology to communicate with WTRU102a, 102b, and 102c via the air interface 116. RAN104 may also communicate with CN106.

[0053] RAN104 may include gNB180a, 180b, and 180c, but it will be understood that RAN104 may include any number of gNBs while remaining consistent with one embodiment. Each of the gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, the gNB180a, 180b, and 180c can implement MIMO technology. For example, the gNB180a and 180b may utilize beamforming to transmit signals to and / or receive signals from the WTRU102a, 102b, and 102c. Thus, the gNB180a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from the WTRU102a. In one embodiment, gNB180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB180a can transmit multiple component carriers to WTRU102a (not shown). A subset of these component carriers may be on the unlicensed spectrum, while the remaining component carriers may be on the licensed spectrum. In one embodiment, gNB180a, 180b, and 180c can implement coordinated multi-point (CoMP) technology. For example, WTRU102a can receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0054] WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using transmissions associated with scalable numerology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may differ for different transmissions, different cells, and / or different parts of the radio transmission spectrum. WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (including, for example, a varying number of OFDM symbols and / or a varying length of absolute time that persists).

[0055] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (such as e-nodes B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unlicensed bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c while also communicating with other RANs such as enodes B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNB180a, 180b, and 180c, and one or more enodes B160a, 160b, and 160c. In a non-standalone configuration, enodes B160a, 160b, and 160c can act as mobility anchors for WTRU102a, 102b, and 102c, and gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0056] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPF) 184a and 184b, routing of control plane information to access and mobility management functions (AMF) 182a and 182b, etc. As shown in Figure 1D, the gNB180a, 180b, and 180c can communicate with each other via the Xn interface.

[0057] The CN106 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and at least one Data Network (DN)185a, 185b. While each of the above elements is shown as part of CN106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0058] AMF182a and 182b can be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N2 interface and can act as control nodes. For example, AMF182a and 182b can be responsible for user authentication of WTRU102a, 102b, and 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selection of specific SMF183a and 183b, management of registration areas, termination of NAS signaling, mobility management, etc. Network slicing can be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of service being utilized by WTRU102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-high reliability low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, and services for MTC access. AMF182a, 182b can provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as Wi-Fi.

[0059] SMF183a and 183b can be connected to AMF182a and 182b in CN106 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN106 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0060] UPF184a and 184b may be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N3 interface, and they can provide WTRU102a, 102b, and 102c with access to a packet-switched network, such as the Internet 110, to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices. UPF184a and 184b can 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, and providing mobility anchoring.

[0061] CN106 can facilitate communication with other networks. For example, CN106 may include or be able to communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN106 and PSTN108. Furthermore, CN106 can provide WTRU102a,102b,102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU102a,102b,102c may be connected to DN185a,185b through UPF184a,184b via an N3 interface to UPF184a,184b, and an N6 interface between UPF184a,184b and local data networks (DN) 185a,185b.

[0062] In view of Figures 1A to 1D and their corresponding descriptions, one or more, or all, of the functions described herein with respect to any of the WTRU 102a to d, base stations 114a to b, e-nodes B160a to c, MME 162, SGW 164, PGW 166, gNB 180a to c, AMF 182a to b, UPF 184a to b, SMF 183a to b, DN 185a to b, and / or any other (one or more) elements / devices described herein may be implemented by one or more emulation elements / devices (not shown). An emulation device may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, an emulation device may be used to test other devices and / or to simulate network and / or WTRU functions.

[0063] Emulation devices may be designed to implement one or more tests of other devices in a laboratory environment and / or a carrier network environment. For example, one or more emulation devices may perform one or more, or all, of the functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in a communication network. One or more emulation devices may perform one or more, or all, of the functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. Emulation devices may be directly coupled to another device for testing purposes and / or tests may be performed using over-the-air wireless communication.

[0064] One or more emulation devices can perform one or more functions, including all of the above, while not implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test laboratory and / or in a test scenario in a non-deployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., including one or more antennas) may be used by an emulation device to transmit and / or receive data.

[0065] In RRC_CONNECTED, the WTRU can detect and measure one or more beams of a cell, and the measurement results (e.g., power values) can be averaged to derive cell quality. The WTRU can be configured to consider a subset of the detected beams. Filtering of these results can be performed at two different levels: namely, at the physical layer to derive beam quality for each detected beam, and at the RRC layer to derive cell quality based on multiple detected beams. Cell quality from beam measurements can be derived in the same way for serving cells and non-serving cells. The measurement report may include measurement results for X best beams if the WTRU is configured to do so by the base station.

[0066] Figure 2 shows an example of a measurement model.

[0067] As shown in Figure 2, the beam-specific sample (A) can represent a measurement within the physical layer 201. The beam-specific sample (A) can be the input to the layer 1 filtering 202. The exact filtering may vary depending on the implementation selection. The processes used to perform the measurement in the physical layer may vary (for example, input A and layer 1 filtering may be implementation-specific).

[0068] Output A of Layer 1 filtering 1 203 can be reported to Layer 3 211 by Layer 1.

[0069] Beam consolidation / selection 204 can be used to consolidate beam-specific measurements to derive cell quality 205. The behavior of beam consolidation / selection 204 can be standardized, and the configuration of this module can be provided by RRC signaling. Cell quality B 205 can be derived from beam-specific measurements reported to Layer 3 after beam consolidation / selection 205. The reporting period in B 205 is A 1 This may be equal to one measurement period in 203.

[0070] Further layer 3 filtering 206 for cell quality 205 can be performed on the measurements provided at point B 205. The behavior of the layer 3 filter can be standardized, and the configuration of the layer 3 filter can be provided by RRC signaling. The filtering reporting period at C 207 may be equal to one measurement period at B 205.

[0071] The result after the measurement has been processed by the Layer 3 filter is represented by C in 207 of Figure 2. The reporting rate may be equivalent to the reporting rate at point B 205. This measurement can be used as input for one or more evaluations 208 of the reporting criteria.

[0072] The evaluation of reporting criteria 208 can be the process of verifying whether a measurement report is required at point D 209. The evaluation can be based on two or more flows of measurements at reference point C 207 to compare different measurements, for example. This is based on inputs C 207 and C 1 As indicated by 210, the WTRU is at least the new measurement result at point C 207, or C 1Each time a report is submitted in 210, the reporting criteria can be evaluated. The reporting criteria can be standardized, and the configuration can be provided by RRC signaling (e.g., WTRU measurement reporting configuration).

[0073] D209, shown in Figure 2, represents measurement report information transmitted over the wireless interface (for example, in a message).

[0074] L3 beam filtering 211 is at point A 1 This can be performed for the measurements provided in 203 (for example, for beam-specific measurements). The behavior of the beam filter can be standardized, and the beam filter configuration can be provided by RRC signaling. The filtering reporting period in E is A 1 This may be equal to one measurement period in [location].

[0075] E 212 represents post-processing measurements (e.g., beam-specific measurements) in the L3 beam filter 211. These measurements are associated with K beams 215. The reporting rate is point A 1 It can be equivalent to the reporting rate in 203.

[0076] The beam selection process 213 can result in the selection of X beams 214 from among K beams 215 measurements provided at point E 212, leading to measurements at point F 216. The beam selection behavior can be standardized, and the configuration of this module can be provided by RRC signaling.

[0077] F 216 represents beam measurement information included in (for example, transmitted over) the measurement report on the wireless interface.

[0078] Layer 1 filtering can employ a specific level of measurement averaging. The method and time by which the WTRU strictly performs the requested measurements can be implementation-specific and can be based on several predetermined implementation requirements for the output in B 205. Layer 3 filtering for cell quality 206, and associated parameters, may ideally not introduce any delay in sample availability between B 205 and C 207. 1 210 is the input used in event assessment 208 for reporting criteria. The L3 beam filtering 211 and associated parameters should ideally not introduce any delay in sample availability between E 212 and F 216.

[0079] Measurement reports can be characterized in one or more ways. For example, a measurement report may include a measurement identification of the associated measurement configuration that triggered the report, cell and beam measurements may be included in a measurement report that can be configured by the network, the number of non-serving cells to be reported may be limited through network configuration, cells belonging to an exclusion list configured by the network may not be used in event evaluation and reporting, conversely, when an allow list is configured by the network, only cells belonging to the allow list may be used in event evaluation and reporting, and beam measurements to be included in a measurement report may be configured by the network (e.g., beam identifier only, measurement result and beam identifier, no beam report, etc.).

[0080] In-frequency neighbor cell measurements and inter-frequency neighbor cell measurements can be based on one or more definitions. For example, in a synchronous signal block (SSB) beam-based in-frequency measurement, the measurement can be defined as an SSB-based in-frequency measurement, provided that the center frequencies of the serving cell's SSB and the neighbor cell's SSB are the same, and the subcarrier spacing of the two SSBs is also the same. For example, in an SSB-based inter-frequency measurement, the measurement can be defined as an SSB-based inter-frequency measurement, provided that the center frequencies of the serving cell's SSB and the neighbor cell's SSB are different, or the subcarrier spacing of the two SSBs is different (for example, in an SSB-based measurement, one measurement can correspond to one SSB, and the WTRU considers different SSBs to be different cells). For example, in a Channel State Information Reference Signal (CSI-RS) based inter-frequency measurement, the measurement can be defined as a CSI-RS based inter-frequency measurement if it is not a CSI-RS based intra-frequency measurement (for example, extended cyclic prefixes (CPs) for CSI-RS based measurements may not be supported in all cases). For example, in a CSI-RS based intra-frequency measurement, the measurement can be defined as a CSI-RS based intra-frequency measurement on the condition that one or more conditions apply, namely that the subcarrier spacing (SCS) of the CSI-RS resource on the neighbor cell configured for measurement is the same as the SCS of the CSI-RS resource on the serving cell indicated for measurement, for 60 kHz subcarrier spacing, the cyclic prefix (CP) type of the CSI-RS resource on the neighbor cell configured for measurement is the same as the CP type of the CSI-RS resource on the serving cell indicated for measurement, and / or the center frequency of the CSI-RS resource on the neighbor cell configured for measurement is the same as the center frequency of the CSI-RS resource on the serving cell indicated for measurement.

[0081] Whether a measurement is gap-assisted or not may depend on the capabilities of the WTRU, the WTRU's active bandwidth part (BWP), and / or the current operating frequency. For example, in an SSB-based in-frequency measurement, if measurement gap requirements information is reported by the WTRU, the measurement gap configuration may be provided according to that information. The measurement gap configuration may be provided if: the WTRU supports only per-WTRU measurement gaps; or the WTRU supports per-frequency range (FR) measurement gaps and any of the serving cells are within the same frequency range being measured. In another example, in an SSB-based in-frequency measurement, if measurement gap requirements information is reported by the WTRU, the measurement gap configuration may be provided according to that information. Otherwise, the measurement gap configuration may be provided at any time if: none of the BWPs configured by the WTRU other than the initial BWP include the frequency domain resources of the SSB associated with the initial DL BWP.

[0082] In non-gap-supported scenarios, WTRU may be able to perform such measurements without a measurement gap. In gap-supported scenarios, it may not be assumed that WTRU can perform such measurements without a measurement gap.

[0083] In some cases, the device may be able to use inter-cell beam management to manage beams in the case of carrier aggregation (CA). In the same scenario, it may also be desirable to support cell changes / additions. There is a need for L1 / L2-based inter-cell mobility techniques and procedures to reduce mobility latency. In a sense, this can be L1 / L2 triggered mobility (LTM).

[0084] LTM may involve the use of L1 / 2 lower-layer signaling for procedures associated with handover, such as measurement reports. This may involve the use of MAC control elements (CEs) as opposed to the use of L3 RRC messages. For example, instead of a base station sending an RRC reconfiguration message to a WTRU, it may send a MAC-CE instead. In one example, a WTRU may be configured with one or more handover parameters, such as configurations for different candidate neighbor cells for handover, and the base station may send a MAC-CE indicating to the WTRU which configuration should be used for the handover. Furthermore, base station decisions to trigger a handover may be based on Layer 1 measurements, such as CSI-RS, instead of relying on RRC measurement report messages.

[0085] Different approaches may be considered, such as configuration and maintenance for multiple candidate cells to enable rapid application of configurations for candidate cells, dynamic switch mechanisms between candidate serving cells (including SpCell and SCell) for potential application scenarios based on L1 / L2 signaling, L1 extensions for inter-cell beam management including L1 measurement and reporting and beam indication, timing advance management, and / or, if necessary, central unit (CU)-distributed unit (DU) interface signaling to support L1 / L2 mobility. In some cases, L1 / L2-based inter-cell mobility procedures may be applicable to one or more of the following scenarios: standalone, carrier aggregation (CA), and new radio (NR) dual connectivity (DC) with serving cell changes within a single cell group (CG); within a DU and between CUs (e.g., applicable for standalone and CA, where no new RAN interface is expected); both within and between frequencies; both FR1 (low frequency band, e.g., sub-6 GHz frequency range) and FR2 (high frequency range, e.g., above 6 GHz, millimeter wave); source and target cells may or may not be synchronized; and / or the case between CUs is not included.

[0086] In some cases, during LTM and / or inter-cell beam management, targeting in-DU and in-frequency scenarios, the serving cell remains immutable (e.g., there is no possibility of changing the serving cell using L1 / 2-based mobility). In FR2 deployments, CAs can be used to leverage available bandwidth, for example, to aggregate multiple component carriers (CCs) within a single band. These CCs can be transmitted on the same analog beam pair (base station beam and WTRU beam). A WTRU can be configured by transmission configuration indication (TCI) states for receiving PDCCH and PDSCH (there can be a fairly large number, e.g., 64). Each TCI state may include an RS or SSB that the WTRU refers to to set its beam. The SSB can be associated with a non-serving physical cell identification (PCI). MAC signaling ("TCI state indication for WTRU-specific PDCCH MAC control element (CE)") can activate TCI states for Coreset / PDCCH. Reception of PDCCH from a non-serving cell can be supported by MAC CE indicating the TCI state associated with the non-serving PCI. MAC signaling ("TCI state activation / deactivation for WTRU-specific PDSCH") can activate a subset of (at most) eight TCI states for PDSCH reception. DCI can indicate any of the eight TCI states. Furthermore, "integrated TCI states" with different update mechanisms (downlink control information (DCI) based) can be supported, but without using multi-TRP. In other cases, support for integrated TCI states with multi-TRP may be available.

[0087] One of the objectives of LTM can be to improve handover latency. In conventional L3 handover or conditional handover, the WTRU can first send a measurement report using RRC signaling. In response to the measurement report, the network (e.g., base station, network node, etc.) can provide further measurement configurations and, in some cases, conventional handover or conditional handover (CHO) configurations. In conventional handover, the network provides configurations for the target cell after the WTRU has reported, using RRC signaling, that the cell meets the configured radio quality criteria. In conditional handover (CHO), to reduce the handover failure rate due to delays in sending the measurement report and then receiving the RRC reconfiguration, the network can provide the target cell configuration, as well as the metrics that determine when the WTRU should trigger the CHO configuration, in advance. However, both of these L3 methods can suffer some amount of delay due to sending the measurement report and receiving the target configuration, especially in the case of conventional (unconditional) handover.

[0088] In particular, one goal of LTM can be to enable rapid application of configurations for candidate cells, including dynamic switching between SCells and PCells (e.g., switching roles between SCells and PCells), without performing RRC signaling. Note that in the case of inter-CUs, relocation of PDCP anchors may be required, and therefore LTM may be excluded; thus, RRC / L3-based methods may be required, at least to support inter-CU handovers.

[0089] Furthermore, with legacy L3 handover mechanisms, any currently active SCells may be released before the WTRU completes the handover to the target cell in the new site's coverage area, and may only be added again after a successful handover, which can lead to reduced throughput during the handover. One of the goals of LTM could be to enable instantaneous CA operation when serving cell changes.

[0090] Figure 3 shows an example of LTM operation using carrier aggregation (CA). In this example, candidate cell groups can be configured by RRC, and dynamic switching between PCells and SCells is achieved using L1 / 2 signaling, for example, MAC control elements (CEs).

[0091] In the example in Figure 3, four cells are considered. These cells can be configured to operate in frequencies ranging, for example, from 2.1 GHz to 26 GHz. This is an example of a possible frequency range and cell frequencies within that range. Those skilled in the art will understand that other frequency ranges and cell frequencies can be adopted, and that the solutions described herein can be used for other frequencies.

[0092] To perform a dynamic switch, the network can send a dynamic switch indication to the WTRU using L1 / 2 signaling, such as MAC CE. The WTRU's MAC layer can receive a MAC CE with a dynamic switch indication from the network. The WTRU's MAC layer can then indicate the dynamic switch to the WTRU's RRC layer. The WTRU's RRC layer can apply the new configuration and perform the dynamic switch. Upon entering a new cell, the RRC layer can send an RRC message in the new cell indicating a successful switch. Optionally, the indication of a successful switch may be sent in the new cell via L1 / 2 signaling, such as MAC CE.

[0093] In the example in Figure 3, the RRC can initially configure all four cells (cells 1 through 4) 301, 302, 303, and 304 as candidate cells, and activate cell 1 301 as a PCell and cell 2 302 as an SCell 305. The WTRU movement direction in Figure 3 is shown from left to right 306, as indicated by the arrows, and the WTRU starts from the leftmost point of arrow 305. In this example, when the WTRU moves and approaches cell 3 303, the network can perform a dynamic switch by sending a first indication (e.g., L1 / 2 MAC CE) 307 that triggers the WTRU (MAC / RRC), changing the SCell from cell 2 302 to cell 3 303. As movement continues, the WTRU may leave cell 3 303, and the WTRU (MAC / RRC) may receive a second indication from the network (for example, in MAC CE) 308 and dynamically switch the Scell ​​back to cell 2 302. Upon leaving cell 1 301, the WTRU may receive a third indication from the network (for example, in MAC CE) 309 and dynamically switch the PCell back to cell 2 302, and when approaching cell 4 304, it may also dynamically switch the SCell back to cell 4 304 309.

[0094] Figure 4 shows an example of the LTM baseline procedure.

[0095] In step 1, the WTRU can send a measurement report message to the base station. The base station can determine to use the LTM and begin preparing the candidate cell.

[0096] In step 2, the base station can send an RRC reconfiguration message to the WTRU that includes the LTM candidate cell configuration of one or more candidate cells.

[0097] In step 3, the WTRU can store the LTM candidate cell configuration and send an RRC reconfiguration completion message to the base station.

[0098] In 4a / 4b, the WTRU can perform DL synchronization and TA capture with candidate cells before receiving a cell switching command. In some cases, DL synchronization for candidate cells prior to a cell switching command can be supported, at least based on SSB. Additionally, TA capture of candidate cells prior to an LTM cell switching command can be supported, at least based on PDCCH ordered RACH, where the PDCCH order is triggered only by the source cell.

[0099] In step 5, the WTRU can perform L1 measurements on the configured candidate cells and transmit lower layer measurement reports to the base station. In some cases, lower layer measurement reports can be carried over L1 and / or MAC. Furthermore, the order of DL / UL sync (sync) (steps 4a / 4b) and L1 measurements (step 5) may be undefined, other techniques described herein may be employed, and / or may be optional.

[0100] In step 6, the base station can perform a cell switch to the target cell and send a MAC CE that triggers the cell switch by including the candidate configuration index of the target cell. The WTRU can then switch to the configuration of the target cell.

[0101] In step 7, the WTRU can perform a random access procedure toward the target cell.

[0102] In step 8, the WTRU can indicate the successful completion of cell switching toward the target cell by sending an uplink message.

[0103] In some cases, the WTRU can perform steps 4-8 multiple times for subsequent LTM cell switching based on the configuration provided in step 2.

[0104] In some cases, uplink control signals, such as MAC-CE and / or RRC messages, can be sent after the WTRU has switched to the target cell to indicate the successful completion of the LTM cell switchover.

[0105] A cell can be in a network energy saving state (NES). For example, a cell can be in a discontinuous transmission (DTX) state or a partial DTX state. For example, in a partial DTX state, one or more downlink channels may be unavailable in the cell, i.e., not being transmitted by the base station. Another example is a cell can be in a discontinuous reception (DRX) state or a partial DRX state. For example, in a partial DRX state, one or more uplink channels may be unavailable to the UE in the cell. A combination of DRX and DTX is also possible. Another example is a cell that is turned off at that moment, for example, in an NES state cell off state, or in an NES state cell off state for a specific duration, or even in an NES state cell off state periodically. An active NES state can be associated with a normal state of the cell, for example, where all channels are operating normally.

[0106] The terms NES state, NES status, and availability state may be used interchangeably in this specification to represent cell states.

[0107] Many NES states can be assumed, and this specification uses several examples to illustrate various functions and system behaviors. For example, an NES state may be a reduced Tx power state, a hibernation state, a microsleep state, a light sleep state, or a deep sleep state. Such examples should not limit the scope of the various embodiments described herein.

[0108] In some cases, a WTRU can determine whether it can transmit or receive on a particular resource depending on the network availability state and / or network energy saving (NES) state, which may imply the base station's power saving status. Availability states can correspond to network energy saving (NES) states, cell DTX mode, cell DRX mode, and / or base station availability states. Availability states can be uplink or downlink specific and may change per symbol, per slot, per frame, or at a longer duration granularity. Availability states can be determined by the WTRU or indicated by the network. In addition to the examples listed above, availability states can be, for example, "On," "DL and UL Active," "UL Only Active," "Off," "Reduced Tx Power," "Hibernate," "Microsleep," "Light Sleep," or "Deep Sleep." Such states can be abstracted by network configuration parameters and / or values, and dynamic indications can point to active availability states (e.g., by DCI or MAC CE signaling).

[0109] NES states can be operator-specific, with each operator selecting which NES states are applicable to their networks. NES states can also be cell-specific, with each operator determining which NES states are applicable to each cell in their networks. NES states can be WTRU-specific, with a specific user or group of users being configured with a specific NES state, such as a "group-specific dormancy state," so that only a specific group of WTRUs behaves as if the cell were in that NES state (e.g., cell-off NES state). This can help save overall energy at the base station, even if the cell is still operational for some selected users (e.g., VIP users). Different categories of users can be defined and billed accordingly.

[0110] Each NES state can have its own NES parameters. For example, the cell-off NES state may imply that the base station's baseband hardware is completely turned off. In the case of the cell-off NES state, the following NES parameters may be relevant: the maximum or minimum duration for which the cell can be turned off, whether or not a broadcast channel is still transmitting in the cell, whether or not paging functionality is still enabled in the cell, and what action the WTRU should take when a page is received during the cell-off state. The WTRU can be configured with these parameters, for example, via the broadcast channel or via a dedicated RRC message. In a reduced Tx power state, the WTRU may be configured with the maximum transmit power. This may imply that only WTRUs near the base station can obtain coverage in that cell. The same parameters can be applied to downlink power. Another example is when UL or DL ​​communication is permitted only at some very basic rate.

[0111] Each operator can select which NES parameters to use and assign values ​​accordingly. The WTRU in those networks can consist of applicable NES states and associated NES parameters for each state. NES states and parameters can be configured in the WTRU via broadcast signaling or dedicated RRC configuration signaling. The WTRU can determine the availability state from receiving availability state indications, for example, via L1 / L2 signaling (e.g., group common DCI or indication), or implicitly from the reception or absence of periodic DL signaling.

[0112] In certain availability states, some DL or UL resources may be unavailable for a specific period of time, which allows the network to turn off baseband processing and other activities. Some measurement resources (e.g., SSB or CSI-RS) may only be available in certain availability states, including RLM, BFD, RRM measurements, CSI-RS feedback configurations, and / or different power offsets for CSI feedback.

[0113] A WTRU can determine whether a resource is available for transmission / reception and / or whether certain measurements are applicable in an active availability state. A WTRU can adapt its active C-DRX cycle, active spatial elements (e.g., antennas or logical ports), active TRP, and / or paging occasions according to the signaled or determined availability state.

[0114] Under certain conditions, the WTRU may also send requests (e.g., wake-up requests) to the network to modify the availability state to a state where resources that would satisfy the WTRU requirements are available.

[0115] Parameters associated with a state can be defined in a parameter set. For example, an NES parameter set may include a configuration to be used during an NES state, which may include one or more of the following: the number of antenna ports, the C-DRX configuration, the measurement configuration (for example, RRM, RLM, and / or BFD), the CSI feedback, the CSI-RS configuration, the SSB configuration, the CHO or mobility candidate, and the set of active TRPs. A WTRU can consist of one or more NES parameter sets for each availability state.

[0116] A WTRU can consist of one or more sets of NES transmit and / or receive parameters for each availability state. NES parameter sets can be configured in a WTRU via broadcast signaling or dedicated RRC configuration signaling. A WTRU can apply a parameter set (e.g., an NES parameter set) according to a determined or signaled availability state. A WTRU can apply one or more applicable configurations depending on the determined NES state. In one example, not all WTRUs may be in the same NES state; for example, a group of WTRUs may be supplied with less power in downlink transmission, thus reducing the energy consumed by the base station without compromising the quality of another group of WTRUs. In another example, an NES state may be defined per cell and be the same for all WTRUs in a cell.

[0117] An availability state can be applicable to at least one transmit, receive, or measure resource. An availability state can be applicable to at least one time period, such as a time slot or time symbol. An availability state can be applicable to a serving cell, cell group, frequency band, bandwidth part, TRP, set of spatial elements, or range of frequencies within a bandwidth part. For example, when the NES state changes in a cell, the WTRU may receive an availability state change indication indicating that this change is only for that cell, but for all cells at the same frequency and / or the same RAT.

[0118] A WTRU may, after receiving DL signaling that alters the availability state of a cell or TRP, consider whether the active availability state associated with the cell, carrier, TRP, or frequency band is "off," "deep sleep," or "micro sleep." For example, a WTRU may receive a turn-off command on broadcast signaling, RRC signaling, DCI (e.g., group common DCI), or DL ​​MAC CE (e.g., the indication part of PDSCH). A WTRU may determine the availability state from receiving availability state indications from, for example, L1 / L2 signaling (e.g., group common DCI or indication) or broadcast signaling associated with the availability state.

[0119] For example, availability state change indications can also be part of SI updates or SIB signaling (e.g., in a separate SIB not read by legacy WTRUs). There may be a common time for all WTRUs in a cell to determine their availability state status.

[0120] For example, a WTRU may determine a change in NES state from the reception of group common command L1 signaling (e.g., group common DCI, multistage DCI, a specific DCI format, or DCI scrambled by a configuration or specified NES-specific RNTI). The L1 signaling may indicate one of the configured NES parameter sets to apply, or, upon determining an NES state change, it may determine a differential configuration from the current set of parameters. Following the reception of the NES state change indication, the WTRU may send a feedback / acknowledgment to the base station, possibly multiplexed with UL data (e.g., MAC CE or part of the UL TB as a subheader indication).

[0121] For example, a WTRU can determine a change in an NES state indication or change from the reception of broadcast signaling associated with an NES state indication or change, including signaling in an SIB or part of a broadcast or multicast PDSCH. A WTRU can explicitly indicate an NES state in an SIB. A WTRU can consist of one or more SIBs exclusively associated with the configuration of NES parameters. A WTRU can be configured to periodically receive such broadcast or multicast indications, and the WTRU can determine that an indication is a false positive if it is not received on an expected periodic occasion and / or if a timer has elapsed since the last reception of the NES state indication. A WTRU can count the number of false positives. Following the determination of one or more false positives of an NES state indication, the WTRU can initiate inter-cell measurements, inter-frequency measurements, and / or inter-RAT measurements, initiate mobility procedures, and / or begin evaluating the configured CHO candidate.

[0122] A WTRU can implicitly assume a specific availability state associated with a cell, carrier, TRP, or frequency band (e.g., "off," "deep sleep," "microsleep," or "hibernate") based on one or more conditions (conditions associated with another event, as opposed to sending a message directly to the WTRU).

[0123] For example, the condition may be the reception of a command or signal indicating a change in availability status, such as group common DCI or RRC signaling or presence signaling in connected mode. The WTRU may implicitly determine availability status from the reception of periodic DL signaling. The WTRU may be configured or specified to associate availability status with one or more DL signal types (e.g., SSB, partial SSB, and / or one or more periodicity).

[0124] For example, the condition may be the reception of a paging message, paging DCI, or paging PDSCH on a subset of POs (e.g., one that matches a configured subset of NES DRX cycles or PDCCH resources). A WTRU may assume a specific availability state after receiving the indication part of a DCI or PDCCH scheduling paging (e.g., based on receiving a P-RNTI, NES-RNTI, or an explicit indication, e.g., on reserved bits). A WTRU may assume a specific availability state after receiving a paging message with a specific P-RNTI. In one example, a newly defined NES P-RNTI, or NES-RNTI, may be configured in the WTRU. A WTRU may assume a specific availability state after receiving a paging message with a specific P-RNTI.

[0125] For example, if an early paging indication (EPI) is configured in a cell, a WTRU can be configured to be part of a device's paging early indication (PEI) subgroup, in which case the PEI can target all WTRUs in the subgroup. A PEI subgroup can be associated with one or more NES states, for example, a WTRU can assume a particular NES state after receiving a PEI with an NES subgroup, if that subgroup is configured and / or associated with an NES state. Indications for applicable NES states or indicators for NES state switching can be present in the paging payload, for example, as a flag part of a paging message or short message. Such paging indications can further indicate alternative cells to monitor the paging channel while the current cell (the cell from which the indication was received) is off, asleep, or in any other NES state. Such paging indications may further indicate or signal applicable reconfiguration parameters (for example, initial access, applicable PRACH resources, applicable SSB / RS occasions, applicable SI cycles, and / or applicable cells and associated availability states).

[0126] For example, the condition could be the base station DTX status (e.g., whether the base station is in active time, whether the associated activity timer is running).

[0127] For example, the condition could be the absence of detection of presence indications in a cell (e.g., the absence of a DL synchronization channel). For example, a WTRU may determine the availability state associated with a cell (e.g., "off" or "deep sleep") if presence indications are not detected in one or more presence indication occasions. For example, a WTRU may assume or change the availability state of a cell after several consecutive false positives or after a timer expires following no detection of presence signals. A WTRU may determine that the availability state is active or inactive after the expiration of a timer associated with the availability state. Such timers may be configured and / or maintained only in RRC connected mode or in other modes (e.g., RRC idle mode and RRC inactive mode).

[0128] For example, "cell-off duration" can be a parameter in the parameter set associated with NES state cell-off. When a cell enters the cell-off NES state, the WTRU is notified (explicitly or implicitly) and can start a timer. When the timer reaches the value of "cell-off duration", the WTRU can assume that the cell is no longer in the NES state cell-off and has returned to the normal state. Optionally, the parameter set associated with NES state cell-off can include an indication of a specific NES state (instead of the normal state), and as a result, when the timer reaches the value of "cell-off duration", the WTRU can assume that the cell is no longer in the NES state cell-off and has entered the specific NES state indicated in the parameter set associated with NES state cell-off.

[0129] For example, a WTRU can implicitly determine an availability state from the absence of receiving periodic DL signaling. For instance, a WTRU can be comprised of a signal quality threshold (e.g., an RSRP threshold), and if the WTRU does not detect a signal associated with an availability state (e.g., a presence signal or SSB) with a signal intensity above the threshold, the WTRU can assume that this availability state is not active, and can assume a different availability state. This criterion can also be combined with the absence of detection of a presence signal identification sequence (e.g., detection of a PSS sequence).

[0130] For example, the conditions can be based on daytime hours, and the WTRU can be configured to automatically assume specific availability states (e.g., off, sleep, or hibernate) for a configured subset of cells (e.g., capacity boosting cells) based on daytime hours. For example, the WTRU can be configured to know that a capacity boosting cell has availability states such as "on" during certain daytime hours, "deep sleep" during other configured hours, and "off" during a third set of configured daytime or nighttime hours.

[0131] For example, the conditions can be based on the availability status of associated cells (e.g., another carrier in the same MAC entity, another carrier in the same cell group, another carrier in the same base station, another sector in the same base station, or a configured associated cell or capacity boosting cell).

[0132] For example, the NES state can be associated with conditions such as the detection of a PSS-only signal or a simplified / minimal (stripped-down) SSB signal.

[0133] For example, the NES state can be associated with conditions such as the detection or absence of RS signals (e.g., CSI-RS, PRS, TRS).

[0134] For example, the NES state can be associated with conditions such as the WTRU's RRC state (idle, inactive, or connected mode).

[0135] For example, the NES state can be associated with conditions, such as whether paging was received within a configured time window.

[0136] For example, the NES state can be associated with conditions such as whether system information (e.g., a subset of periodic SI or SIB) has been received within a configured time window.

[0137] For example, an NES state can be associated with conditions such as when the measured channel condition falls below or exceeds a threshold. A WTRU may assume a change in the NES state based on a change in the measured channel condition or by making channel measurements that fall below or exceed a threshold. For example, a WTRU may determine the NES state using a drop in an SSB or CSI-RS measurement, possibly in combination with other signaling. For example, a configured window following a DCI reception may be used to measure SSB and / or CSI-RS for a drop, and if a difference in SSB-RSRP drop is measured, the WTRU may determine that the NES state has changed and assume an associated action for such an NES state (e.g., a trigger for CHO candidate selection or group scheduling for mobility commands).

[0138] A WTRU can be configured to monitor indications that can characterize an NES state. An NES state can be associated with a base station and / or cell. For example, a WTRU may assume the same NES state for all cells that are part of the same base station, e.g., cells of the same MAC entity. NES state indications can be transmitted in channels (e.g., PDCCH) and / or signals (e.g., sequences, such as SSB for presence indications). An NES state or NES state change indication can indicate a level of activity that a WTRU can expect from the associated base station and / or cell, such as reduced or increased activity (e.g., relative to a threshold). An NES state may contain activity information from other base stations and / or cells. NES state indications can be transmitted in PDCCHs that include group common signaling. For example, a network may transmit an NES-specific RNTI or group common DCI to a group of WTRUs (e.g., WTRUs in a serving cell) indicating a change in availability state in UL and / or DL. The PDCCH's CRC can be scrambled with a dedicated "activity indication RNTI or NES-RNTI". The WTRU can consist of at least one search space associated with the monitoring occasion of the activity indication PDCCH. The indication can consist of go-to-sleep signals, such as a predefined sequence. When the WTRU detects this sequence, it can anticipate a reduced availability state over a specific duration. The WTRU can activate the C-DRX for the indicated time period. Alternatively, two sequences can be used to indicate normal activity and reduced activity.

[0139] Signaling within PDCCH or activity indications may include one or more parameters.

[0140] For example, the parameter could be the expected availability state (e.g., availability state) of an associated base station / cell over a specific time interval. The availability state can be predetermined and / or configured, and may consist, for example, of normal activity and reduced activity. Signaling can indicate the availability state. For example, bit "1" may indicate normal activity and bit "0" may indicate reduced activity.

[0141] For example, parameters can be transmit and / or receive attributes for each availability state. For example, during some availability states, the WTRU may not be expected to monitor some PDCCH search spaces (e.g., all SSs), and / or receive some types of PDSCHs (e.g., all PDSCHs), and / or transmit PUCCH / PUSCHs, and / or perform some measurements. The WTRU can start or stop monitoring PDCCH and / or TCI states associated with determined NES states, including PDCCH resource or transmit configuration information (TCI) states associated with (de)activated TRPs or spatial elements.

[0142] For example, parameters can be a set of configurations that can be associated with an availability state and used / applied when that availability state is indicated (e.g., NES parameter set). For example, SS configuration, CSI reporting configuration, index of submitted SSBs, etc. Each set of configurations can have attributes associated with an availability state. For example, a tag that can be set for "reduced activity".

[0143] For example, a parameter can be a time interval over which an availability state is assumed and can be signaled in a PDCCH or as part of an activity indication. In one case, the time interval can be represented using a bitmap, where each bit in the bitmap can be associated with a specific duration, such as a slot or frame. For example, bit "1" might indicate normal activity, and bit "0" might indicate reduced activity for the associated frame. In another case, the time interval can be represented by a start time and the length of the interval. The start time can be defined, for example, by adding a fixed offset to the time the indication was received. The length of the interval can be configured or signaled in the indication PDCCH.

[0144] For example, a parameter can be a time interval over which the availability state is assumed, and can be predetermined. WTRU can assume a break delay (for example, more generally, the time until the NES state changes) after receiving an NES state change command (e.g., after the last symbol or slot in which the command was received). The break time can be absolute time, over several symbols, or over several slots.

[0145] The WTRU may determine that uplink or downlink resources are available for transmission / reception and / or measurement for a determined network availability state if they are applicable in the active availability state. The WTRU may determine that a subset of measurement resources and / or signals (e.g., SSB, CSI-RS, TRS, PRS) are not applicable in some availability states. The WTRU may determine that a subset of uplink or downlink resources (e.g., PRACH, PUSCH, PUCCH) are not applicable in some availability states. The WTRU may transmit certain uplink signals only in a subset of network availability states (e.g., SRS, pSRS, PRACH, UCI).

[0146] In some cases, a WTRU may initiate evaluation of CHO candidates on an alternate cell when it performs cell (re)selection, mobility to another serving cell, triggers mobility-related measurements, and / or determines an NES change on a camped cell or serving cell. A WTRU may be configured or predefined by an alternate serving cell to perform initial access, mobility, or cell reselection when the current serving cell or capacity boosting cell (e.g., a cell not configured as an alternate cell) is turned off (NES state cell off) or when certain conditions are met. A WTRU may be configured for each broadcast signaling or dedicated signaling, with a list of fallback or alternate serving cells, possibly per serving cell, per base station, per PLMN, or per network identification.

[0147] In one example, a WTRU can initiate a cell reselection or mobility procedure to an alternative serving cell associated with the cell or base station from which the turn-off indication was received. In another example, a turn-off or go-to-sleep indication can dynamically tell the WTRU which cell to fall back to or connect to, for example, by dedicated signaling or broadcast signaling. The fallback / alternative cell can be configured or predefined to be a cell within the same base station from which the sector entered an NES state (e.g., off, sleep, or reduced power). In another example, the fallback cell can be predefined as the master node cell if the WTRU is in dual connectivity. The fallback / alternative cell can be configured or predefined to be a cell associated with a different RAT or frequency band. For example, a WTRU can fall back to an LTE or FR1 cell associated with the cell or base station from which the turn-off indication was received (e.g., if the WTRU is in a CA or DC using multiple RATs or multiple frequency bands).

[0148] The terms alternate cell and stable cell may be used interchangeably as described herein. A stable cell is a cell that may change its NES state infrequently (where “infrequently” can be defined by a parameter such as a percentage of time). The WTRU may consist of a list of stable cells (e.g., alternate cells that do not turn off, e.g., several macrocells), and the list may be either a list of alternate cells per serving / camped cell, or a general list of PCIs for the entire network, tracking area, etc. The WTRU may consist of the measurable configuration for alternate cells. Alternate cells may be pre-configured to be CHO candidates and / or potentially considered CHO candidates only if the source cell turns off / activates the NES.

[0149] In at least one scenario of the basic LTM procedure, the network may first pre-configure multiple target cell candidates in the RRC, then the WTRU may be triggered to perform DL and UL synchronization on one or more target cells before finally receiving a MAC CE that triggers a reconfiguration / handover.

[0150] Turning off some cells can achieve NES by reducing the amount of power consumed by network equipment associated with those cells. By selectively turning off less frequently used cells, or by strategically reducing the number of cells in a particular area, the network can operate more efficiently, reducing energy consumption and costs while maintaining adequate coverage and capacity. This can result in significant energy savings over time, reduce the environmental impact of the network, and improve its sustainability, especially during periods of low demand (e.g., at night).

[0151] LTM configurations can provide a means to reduce downtime for WTRUs. Energy saving mechanisms can select some of the cells configured as LTM candidates. Smooth handling of LTM and NES procedures may be required to ensure that the network can conserve energy whenever possible without exposing WTRUs to the risk of failures (e.g., LTM failures, handover failures, etc.). Therefore, LTM procedures should take into account the possibility of dynamic changes in cell configuration by the NES.

[0152] In general, “performing LTM” or “performing the LTM procedure” as described herein may refer to performing any combination of the steps described in Figure 4 and / or all of those steps. For example, performing early synchronization in DL and / or UL to one or more candidate cells, performing L1 measurements, reporting on one or more of the candidate cells, and / or switching between candidate cells (e.g., performing a handover) (for example, “performing LTM” may mean that the WTRU moves / switches between multiple candidate cells during the procedure).

[0153] Generally, one or more candidate cell sets described herein may be a group of two or more RRC configurations corresponding to handover configurations for one or more candidate SpCells and optionally for SCells. This may be modeled or received as one or more complete RRC reconfiguration messages, one or more cell group configurations, or one or more cell configurations. Each candidate cell configuration may include a candidate configuration identifier, and each candidate cell group may include a candidate cell group identifier. Where grouping is performed in the RRC, switching between different sets of candidate cells may include updating a serving cell index or candidate configuration index used in L1 and MAC signaling to refer to a specific index (for example, a MAC CE triggering a reconfiguration may include a candidate configuration index that informs the WTRU which cells should be reconfigured).

[0154] One or more candidate cell groups can be configured in the RRC as a single list or group of candidate cell configurations. Grouping may occur in the early sync or LTM execution phase rather than the configuration phase, meaning that while a set of candidate cells may be considered a single group with respect to the RRC configuration list or group, the cells selected for performing the early sync, L1 measurement, and LTM execution depend on further grouping into multiple subsets of the entire candidate cell list. In other words, grouping itself may not be modeled in the RRC using candidate configuration identifiers, but grouping can be performed as part of the early sync or LTM execution procedure.

[0155] When referring to an LTM candidate configuration as disclosed herein, this can be applied to any type of pre-configured cell information. For example, a WTRU may consist of one or more conditional reconfigurations, such as a conditional handover (CHO), conditional PSCell addition (CPA), or conditional PSCell modification (CPC), which are effective before and / or after a cell change, or effective in some cells.

[0156] As disclosed herein, L1 measurements may consist of measurements such as RSRP, RSRQ, and RSSI, performed by a WTRU of a cell, beam, set of cells, or set of beams. Such L1 measurements may be similar to L3 measurements reported in RRM, but with differences in filtering, the reference signal measured, and the reporting mechanism.

[0157] The measurements described herein may refer to L1 measurements for LTM. However, some examples may also apply to RRM / L3 measurements, as well as other measurements (e.g., speed, location, height, traffic, etc.).

[0158] In some cases, a WTRU may consist of a pre-configured pattern of neighbor cell NES states. Generally, this can be a list of cells with associated NES-related parameters or information. For example, a WTRU may consist of a list of cells configured with at least one NES technique, a list of cells capable of servicing an NES-enabled WTRU, or a list of cells actively using at least one NES technique (e.g., cell DTX, spatial or power domain adaptation, cell turn-off, or sleep). In some cases, a WTRU may consist of multiple patterns that can be referenced using an index or identity.

[0159] For example, a list of neighbor cells is provided with a status indication or several parameters, using a persistent identifier such as PCI or cell ID, or a temporary identifier such as a serving cell identifier or candidate cell identifier. The (for example, neighbor) cell status may be configured per cell, or there may be a common configuration that can be shown as applicable to multiple cells, for example, a configuration consisting of cell status = on, cell DTX / DRX pattern = pattern A, which may be applied to one or more cells in the list.

[0160] In some cases, pre-configured NES patterns can be provided in broadcast signaling, for example, in SIBs. In one example, this can be provided to WTRUs using dedicated signaling, for example, in RRC reconfiguration.

[0161] The WTRU disclosed herein may have any of the parameters or configurations disclosed herein, and / or the WTRU may have an NES alternative cell as described herein.

[0162] Changes to the NES status or parameters may affect one or more of the following LTM-related parameters or procedures: the LTM candidate list; CSI reporting which may update the SSB or CSI-RS that is active in some of the candidates; DL sync which may depend on the NES status to determine whether the WTRU maintains downlink synchronization to the cell; UL sync which may depend on the NES status to determine whether the WTRU maintains TA for candidate cells; RA type which may determine whether the WTRU uses a specific RA procedure (e.g., 2-step, 4-step, or RACH-less) depending on the NES status; L1 event trigger reporting which may have a new MAC CE for L1 event reporting, limited to active NES cells only; updating thresholds or L1 reporting criteria based on cell status; updating the active BWP which should be used when triggering LTM; and / or replacing some of the candidate cells with NES alternative cells depending on the NES status of the candidate cells. WTRU can modify or apply a subset of these LTM parameters depending on the direction of the NES state change of the source cell and / or candidate cell (e.g., On to OFF vs. OFF to On, cell DTX activation vs. cell DTX deactivation, reduction of spatial / power domain coverage, etc.).

[0163] Figure 5 shows an example of an LTM configuration update based on a common indication that updates the NES state of a cell. Here, an exemplary message sequence for an LTM configuration update based on a common indication that updates the NES state of a cell is shown. A key aspect of this solution is that information related to the NES information update is transmitted in the common indication. In the example in Figure 5, a System Information Block (SIB) is used.

[0164] Firstly, a WTRU can consist of one or more sets of NES state parameters associated with one or more NES states.501 For example, in a periodic cell-off NES state, the set of NES state parameters may define the start time, the periodicity of the cell-off NES state, the duration of the cell-off NES state, and the end time. If an indication is used to notify the WTRU that a cell is entering that state, the start time may not be required. The same may be true for the end time, which may be based on an indication sent to the WTRU.

[0165] WTRU can be composed of a subset of cells as LTM candidates via dedicated RRC signaling, such as using RRC reconfiguration messages.502

[0166] To receive common signaling, WTRUs can be configured by a network using group common signaling. This can be achieved by providing WTRUs with group common RNTIs (e.g., cell-specific RNTIs or NES-RNTIs).

[0167] Since the WTRU is pre-configured with a set of NES state parameters, the indication that notifies the WTRU that a cell is entering a given NES state can be based on a short indication 503, and the parameters associated with each state do not need to be sent by the short indication.

[0168] Short indications 503 can be transmitted, for example, in DCI 503. DCI can be transmitted in a CORESET configured for an NES-specific RNTI, a group-common RNTI, or another common RNTI. The RRC configuration for NES indications can provide a mapping between the PCI and the bits in the DCI to which the indication is transmitted. Alternatively, the bits can be predefined or preprovisioned in the WTRU. NES indications can be transmitted in a bitmap pattern within the DCI. NES state indications may be limited to certain cells (e.g., unstable cells).

[0169] For example, the bitmap shown in DCI can correspond to an indication of which of the alternative cells or configured candidate cells should be considered for LTM, and the bitmap size can be determined as the size of the alternative cell candidate configured for the source cell from which DCI received the information.

[0170] Optionally, short indication 503 can be transmitted in MAC-CE, or in scheduled data via NES-specific DCI, group-common DCI, or WTRU-specific DCI. Signaling can be bitmap-based, with preconfiguration associating cell identification with specific bits in the bitmap.

[0171] More than one type of MAC-CE may be used. One NES indication MAC-CE may include a bitmap that provides NES state indications for cells configured to be indicated through MAC signaling. One long NES indication MAC-CE may be used, which can provide NES state indications for a set of cells configured to be indicated. The long NES indication MAC-CE may also provide additional attributes related to the NES procedure. In some cases, timing information may be provided regarding when the network plans to turn these cells ON or OFF in order for each cell to be ON / OFF. NES state indications may be limited to unstable cells.

[0172] For example, the bitmap shown in the MAC CE can correspond to an indication of which of the alternative cells, astable cells, or configured candidate cells should be considered for the LTM. The MAC CE size can be fixed, but the cells showing a portion of the MAC CE can be reconfigured. For example, the MAC CE size can be fixed to show x candidate or alternative cells, but the list of configured alternative cells can be y (where y > x). The RRC(re)configuration can configure which of the y alternative cells should be included in the MAC CE.

[0173] Long MAC-CEs can provide attributes that modify WTRU processing / behavior for LTM procedures. In one example, the indication may consist of a trigger to provide LTM measurements to the network at a specific time.

[0174] Optionally, short messages can be used to transmit short indications 503. Short messages can be transmitted on the PDCCH using P-RNTI, with or without an associated paging message, for example, using the short message field in DCI format 1_0. Signaling that propagates changes in NES state can use one or more of the reserved bits (by redefining the bits), and the NES state can be associated with a serving cell. Bits can indicate a single on / off indication using a single bit, or a combination of bits can be used to provide more information, such as a configuration index, or to indicate the presence of an associated paging message. An associated paging message, or any associated message type received on the PDSCH, may contain further information, such as an index to a predefined list of NES cell states, or may provide attributes that modify WTRU processing / behavior for LTM procedures. In some cases, an indication may consist of a trigger to provide an LTM measurement to the network at a particular time.

[0175] For example, one bit may indicate a flag for an NES state change associated with the source cell. Another bit may indicate an NES state change associated with at least one other candidate cell. Upon receiving such a flag, the paging message may include further information about the nature of the NES state change. The paging message may also include further information about the NES state change of the candidate cell.

[0176] The NES status parameters can be updated via SIB update 504. The LTM measurement report trigger can also be updated 505. When the trigger occurs, the WTRU can send the LTM measurement report and complete the LTM procedure 506.

[0177] Figure 6 shows an example of the interaction between NES states and LTM operations. The WTRU can receive configuration information for one or more NES states 601. The configuration information can be sent in cell-specific messages, e.g., common RRC messages (e.g., SIB messages) 601, or in RRC-specific messages (e.g., RRC reconfiguration messages, not shown in Figure 6). The configuration information may include NES parameters for each of the configured NES states 602. An NES state cell off can be defined by its associated parameters to indicate that the cell can be turned off for a specific duration.

[0178] The network can configure a set of neighbor cells as candidate cells. These candidate cells can be configured for LTM. These candidate cells can be selected by the network based on WTRU location. As an example, in Figure 6, cell 1 to cell (x+y) is configured as LTM candidate cell 603.

[0179] This 603 can be sent in UE-specific RRC messages (e.g., RRC reconfiguration messages). Optionally, it can be broadcast in cell system information.

[0180] An LTM measurement triggering event (referred to as an LTM event in Figure 6) is an event identified by the WTRU that can trigger the WTRU to perform an LTM measurement. The WTRU monitors for events, and when an event is triggered (i.e., the event occurs), the WTRU begins to perform the LTM measurement associated with that event.

[0181] An LTM measurement reporting triggering event (LTM-MR event) is an event that triggers a WTRU to report an LTM measurement to the network (e.g., a serving cell). LTM-MR events can be associated with LTM measurement results so that conditions related to the measurement result can trigger reporting from the WTRU. Measurements are performed by UEs in specific cells, including serving cells and neighbor cells. The WTRU monitors for events, and if an event is triggered (i.e., the event occurs), the WTRU reports the LTM measurement result. The result may be based on the LTM measurement performed.

[0182] The UE can optionally be pre-configured with one or more LTM events associated with a candidate cell. The LTM event can optionally be an implicitly triggered event that the WTRU is pre-configured to identify, as described in the previous paragraph of this specification. Optionally, the network can configure an LTM event in the WTRU using an RRC message.603 In Figure 6, the network configures the WTRU with an LTM event (e.g., an RRC reconfiguration message) when configuring an LTM candidate cell.603 An LTM-MR event can also be configured in the WTRU via an RRC-only message.603

[0183] LTM events can be associated with a cell's NES state. For example, an LTM event might be an event where one or more cells from a candidate set of cells enter a particular NES state. For example, a WTRU might be triggered to perform an LTM measurement when one or more cells from the candidate set change their NES state. The new NES state might be configured to be NES state cell off.

[0184] The network can then send L1 / 2 signaling messages 604 indicating the activation of the NES state for one or more cells from the configured candidate cells. For example, in Figure 6, candidate cells from cell 1 to cell x are indicated by WTRU entering NES state cell off 605. The NES state activation indication can be a bitmap.

[0185] As mentioned above, the LTM event for the example shown in Figure 6 is that an LTM measurement is triggered when one or more cells from the candidate set change their NES state to NES state cell off. Thus, the WTRU may be monitoring for that event and it identifies the LTM event 606. In this example, the WTRU can be configured to start performing an LTM measurement on cells that are not in NES state cell off when it identifies the LTM event. Candidate cells from cell (x+1) to cell (x+y) are not in NES state cell off, and therefore the WTRU can start measuring candidate cells from cell (x+1) to cell (x+y) 607.

[0186] The WTRU may monitor for LTM-MR events. In the example in Figure 6, the WTRU identifies the occurrence of an LTM-MR event. LTM-MR events can be associated with the signal strength of a candidate cell, the SINR of a candidate cell, and a comparison between the serving cell and the candidate cell. LTM-MR events can be associated with events that can trigger a handover.

[0187] Measurement reports can be sent to the network via L1 / 2 signaling messages, such as using MAC CE 609. Based on the received measurements 609, the network can then send an L1 / 2 signaling message indicating that the WTRU will switch to a target cell 610. The target cell can be one of the candidate cells that is not in NES state cell-off and that the WTRU has measured and reported to the network. The received signaling can trigger the WTRU to switch to the indicated target cell 611.

[0188] Figure 7 shows exemplary dedicated and dynamic indications for enabling / disabling different LTM neighbors based on NES status. As illustrated, there can be a message sequence for dynamic indications for enabling / disabling different LTM neighbors based on NES status. A key aspect of this example is that the NES status of neighbor cells is made known to the WTRU using MAC CEs sent to the WTRU using dedicated signaling. In this approach, the network can dynamically update the LTM candidate NES status for each WTRU, which can provide best performance, for example, when the NES status is highly dynamic according to the scheduler.

[0189] As shown in Figure 7, first, the LTM candidate is pre-configured in the WTRU.701 The pre-configuration may include cell-specific NES information, which contains LTM-specific information that depends on the cell's NES state.701 This can be provided by RRC reconfiguration or SIB.701 This can be different pre-configured NES cell state patterns (e.g., active cell, load, priority, threshold, DRX config, etc.).

[0190] The WTRU can receive indications of the NES state of the current cell and one or more neighbor LTM candidate cells. The MAC CE bitmap may contain indices to pre-configured cell state patterns. In some situations, a MAC CE containing a bitmap may be received by the WTRU. Each bit in the MAC CE may refer to an LTM candidate cell ID or serving cell ID and indicate whether the NES state is on (e.g., bit = "1") or off (e.g., bit = "0"). In another example, the WTRU may not know the nature of the candidate cell's NES state but can use the bit indications to know whether the cell should be considered for LTM. Each bit in the MAC CE may refer to an LTM candidate cell ID or serving cell ID and indicate whether such a cell should be considered for LTM (e.g., bit = "1") or whether such a cell should be excluded from LTM (e.g., bit = "0"), where such indications may only be for a list of cells configured as astable cells. In some cases, MAC CE includes an index that references a pre-configured NES pattern or state.

[0191] Based on the received MAC CE information, the WTRU can update LTM candidate cells and / or LTM parameters, including updating the CSI reporting trigger.

[0192] Upon receiving the measurement report, the network can determine to hand over the WTRU to one of the reported cells.704 The network can send a control MAC CE to the target cell indicating the cell switchover. The WTRU can send a switchover indication to the target cell, such as LTM complete, handover complete, or RRC reconfiguration complete.706

[0193] Figure 8 shows an example where a cell switching command includes an indication of the NES status for the cell sending the cell switching command.

[0194] A key aspect of this example is that the NES state of the source cell can be communicated to the WTRU using MAC CE as part of the LTM cell switching indication. In this technique, the WTRU can be informed of the NES state of the cell that was just visited when the cell switching was triggered. In this case, it may not be necessary to transfer information / coordinate between cells.

[0195] First, the WTRU can receive a pre-configured cell-specific NES information, which includes LTM-specific information that depends on the cell's NES state.

[0196] WTRU is an 801 that can receive the configuration of LTM candidate cells.

[0197] The WTRU can receive L1 / 2 signaling (e.g., MAC CE) which includes an LTM cell switching indication, as well as a cause value indicating that the source cell has been switched off or has changed its NES state, and / or an NES indication of a delay for cell switching.

[0198] The WTRU can perform reconfiguration according to the indicated candidate cell received in the LTM cell switching command, and, if indicated, can release or update the source cell RRC candidate configuration after the indicated delay.

[0199] In one example, the WTRU may receive additional NES information in the same MAC CE that triggers the cell switch. The MAC CE might include, for example, a candidate configuration ID (e.g., the ID of the target cell configuration) and an indication of a change in the source cell's NES state. In some situations, a separate MAC CE containing this additional information may be provided before the LTM execution MAC CE.

[0200] For example, an NES state change indicator can be a single flag indicating a switch between two binary states. In some situations, an NES state change indicator can be an index that identifies a pre-configured NES state. A WTRU can exclude cells indicated as being in an NES state from the list of candidate cells considered for the LTM.

[0201] In one example, a WTRU may receive (for example, in MAC CE or DCI) a list of neighbor cells that are to be turned on or no longer apply NES techniques (e.g., cell DTX, spatial or power domain adaptation). Upon receiving such an indication, the WTRU may initiate LTM-related measurements for the indicated cells and implement mobility if the configured mobility conditions are met.

[0202] For example, NES information received by MAC CE can provide the status or next status of the cell that sent MAC CE.

[0203] For example, NES information may further include a timer value indicating the time (e.g., a few milliseconds or seconds in the future) when a state change will occur. In some situations, the time indication may have a value of either "immediately" or "at a pre-configured time," where the pre-configured time may be a fixed value, pre-provisioned, or configured in a quasi-static manner, for example, with an SIB or dedicated signaling. For example, a WTRU may consist of a switch-on period, a switch-off period, a cell DTX activation period, and a cell DTX deactivation period. Upon receiving a MAC CE indicating the next NES state change, the WTRU may assume that the indicated neighbor cell will apply the NES state change after the configured period has elapsed, and the WTRU may initiate LTM-related measurements during such a duration or after the configured period has elapsed (e.g., if the cell is turned off).

[0204] Figure 9 is an exemplary flowchart of the WTRU LTM procedure while the WTRU receives common signaling with NES indication. In this example, the network can update the status of LTM-configured candidates for the WTRU. Furthermore, this example has a flowchart for updating LTM candidate configurations using group common signaling-based indication. As shown in the diagram, initially, the WTRU consists of NES dynamic indications that can be provided in group common signaling. The RRC configuration provides details regarding cell identification and dynamic indication patterns. The WTRU can consist of an LTM procedure with a set of LTM candidates and a reporting mechanism for the configured candidates. The WTRU can be configured to handle LTM candidates with respect to NES (ON / OFF) indications. The WTRU can, for example, stop monitoring an LTM candidate that the network is planning to switch to OFF. Furthermore, there can be two sets of thresholds for LTM candidates (e.g., two sets of offsets). According to the NES indications, one set of thresholds may be applicable for an LTM candidate when the serving cell is ON, and the other set may be applicable when the serving cell is OFF. The WTRU can monitor, measure, and provide reports regarding LTM candidates according to the LTM configuration.

[0205] A WTRU can receive group common signaling that provides updates on the status of neighbor cell NES states. NES state indications may include cells that are turned ON or OFF with (pre)configured / indicated time delays. These may include NES neighbor cell configuration IDs or mapping tables so that the WTRU can associate the correct NES state with the relevant cell.

[0206] WTRU can identify NES indications from group common signaling for cells that are LTM candidates 903.

[0207] WTRU can remove LTM candidates that have shown an NES indication with status OFF from the set of actively monitored LTM candidates.

[0208] The WTRU can activate an LTM candidate from the set of actively monitored LTM candidates that has shown an NES indication with status ON on the network. WTRU can perform measurements across actual LTM candidates. WTRU can provide the network with measurement reports of the strongest (a configurable number of strongest, e.g., N) cells by sending reports.

[0209] WTRU 907 can receive network indications for LTM switching to one of the candidates.

[0210] WTRU 908 can perform LTM switching to network-indicated cells.

[0211] Figure 10 shows a flowchart of an example of group-common NES indication and WTRU reporting when a SpCell enters NES state cell-off mode. In this example, the network updates the status (state) of the SpCell for the WTRU within the NES-common indication. Similar to SIB-based methods, the WTRU can be configured to trigger measurement reporting when the SpCell is turned off in order to identify the most suitable alternative beam or cell (e.g., NES alternative cell).

[0212] First, a WTRU can be comprised of NES dynamic indications that can be provided in group common signaling.1001 The RRC configuration can provide configuration information for LTM and NES operations. The configuration information may include details about cell identification and dynamic indication patterns. A WTRU can be comprised of an LTM procedure with a set of LTM candidates. A WTRU can be configured to handle LTM candidates with respect to NES (ON / OFF) indications. This can be configured, for example, by stopping monitoring for LTM candidates that the network is planning to switch to OFF. Furthermore, there can be two sets of thresholds for LTM candidates (for example, two sets of offsets). According to the NES indications, one set of thresholds may be applicable for LTM candidates when the serving cell is ON, and the other set may be applicable when the serving cell is OFF.

[0213] WTRU can be configured by a special reporting mechanism if NES signaling provides indication of PSCells that are turned OFF.

[0214] Depending on its configuration, the WTRU can monitor, measure, and provide (e.g., send) reports regarding measurements of LTM candidate cells.

[0215] WTRUs can receive group common signaling that provides updates on neighbor cell NES status 1002. NES status indications may be cells that are turned ON or OFF with a (pre)configured / indicated time delay. Signaling may include NES neighbor cell configuration IDs or mapping tables so that WTRUs can associate the correct NES status with the relevant cells 1003.

[0216] WTRU can identify NES indications from group common signaling for cells that are LTM candidates.

[0217] The WTRU can remove LTM candidates that the network has indicated have a state OFF from that set of actively monitored LTM candidates.1004 The WTRU can monitor LTM candidates that are indicated to be ON.1005

[0218] The group common signaling that provides the NES status may include a turn-off indication for SpCell 1006, in which case the WTRU can trigger a special report to the network 1007. Otherwise, the WTRU can measure LTM candidates and provide the network with a measurement report of the strongest (e.g., the strongest of any configurable number) cell 1008.

[0219] WTRU can receive network indications for LTM switching to one of the candidates 1009.

[0220] WTRU can perform LTM switching to the network-displayed cell 1010.

[0221] Figure 11 shows a flowchart of an example of an LTM update using SIB-based NES indication. In this example, there can be an SIB-based design for NES indication and WTRU update in an LTM configuration.

[0222] A WTRU can be configured by an NES, and NES indications for a set of cells are provided through an NES SIB. An NES SIB with (pre)configuration can specify cell identification and NES status updates for the cells.1101 NES indications can also provide, with a suitable level of granularity, when a cell changes to the indicated status.

[0223] The WTRU can be configured to trigger a special measurement reporting mechanism when the SpCell is turned off to identify the most suitable alternative beam or cell (e.g., an NES alternative cell).1101 The WTRU can consist of an LTM procedure with a set of LTM candidates and a reporting mechanism for the configured candidates.

[0224] The WTRU can be configured to handle LTM candidates with respect to the NES(ON / OFF) indication provided in the NES SIB. This can be configured, for example, by stopping monitoring LTM candidates that the network is planning to switch to OFF. Furthermore, there may be two sets of thresholds for LTM candidates (for example, two sets of offsets). According to the NES indication, one set of thresholds may be applicable for LTM candidates when the serving cell is ON, and the other set may be applicable when the serving cell is going OFF.

[0225] WTRU can monitor, measure, and send reports regarding LTM candidates according to the LTM configuration.

[0226] A WTRU can receive paging regarding NES SIB changes.1102 In one case, a P-RNTI can be used to indicate NES SIB change indications. In another case, a new P-NES-RNTI can be used to provide NES SIB change indications. This eliminates the need for non-NES WTRUs to decode paging and subsequent system information capture.

[0227] A WTRU can intercept a SIB (e.g., an NES SIB) that provides NES information.1103 An NES SIB can provide NES information for a configured set of cells. If an NES SIB is not scheduled, a WTRU can request the network to receive an NES SIB through dedicated signaling. An NES SIB can provide updates on the status of neighbor cell NES states. An NES state indication can be a cell that is turned ON or OFF with a (pre-configured) / indicated time delay.

[0228] WTRU can identify NES indications from NES SIB for cells that are LTM candidates.

[0229] The WTRU can remove LTM candidates that the network has shown an NES indication with status OFF from that set of LTM candidates that are actively being monitored 1105. The WTRU can activate monitoring of LTM candidates that the network has shown an NES indication with status ON 1106. The WTRU can report, for example, measurements of N best cells 1107.

[0230] Group common signaling can provide SpCell with an NES state change to OFF, in which case WTRU can trigger a special measurement report to the network configured for when PSCell is OFF.1108 This report when SpCell is OFF can be provided via a special resource (pre-configured) for the WTRU. Alternatively, WTRU can be pre-configured to send scheduling requests (SRs) that WTRU can send to the network when SpCell is OFF. The network can provide UL grants through which WTRU can provide measurement reports, which can be MAC-based or RRC-based reports. WTRU can measure LTM candidates and provide the network with measurement reports of the strongest (e.g., the strongest of a configurable number) cells. In some cases, this measurement report can be performed using L1 event trigger reports, CSI reports, and WTRU can indicate the best beams and / or cells, along with their associated measurements (e.g., RSRP). In some cases, a specific CSI reporting configuration may be applied to enable reporting of certain specific resources (e.g., beams on NES alternative cells).

[0231] The WTRU can receive network indications for LTM switching to one of the candidates.

[0232] WTRU can perform LTM switching to the network-displayed cell 1110.

[0233] Figure 12 shows a flowchart of an example of LTM updating using SIB-based NES indication and conditional LTM. In this example, an SIB-based method or a group common indication method for NES indication, WTRU updating of the LTM configuration, and the possibility that the WTRU may autonomously trigger conditional LTM through the previous configuration when the current SpCell is OFF.

[0234] WTRU can be configured with NES support, and NES indications for a set of cells are provided through the NES SIB. A (pre)configured NES SIB can specify cell identification and NES status updates for the cells. The NES SIB can also provide, with a suitable level of granularity, when the cells change to the indicated status.

[0235] A WTRU can consist of a set of LTM candidates and an LTM procedure with a reporting mechanism for the configured candidates. A WTRU can be configured to handle LTM candidates with respect to the NES (ON / OFF) indication provided in the NES SIB. This can be configured, for example, by stopping monitoring for LTM candidates that the network is planning to switch to OFF. In addition, there may be two sets of thresholds for LTM candidates (e.g., two sets of offsets). According to the NES indication, one set of thresholds is applicable for LTM candidates when the serving cell is ON, and the other set is applicable when the serving cell is going OFF.

[0236] WTRU can monitor, measure, and send reports regarding LTM candidates according to the LTM configuration.

[0237] A WTRU may receive paging regarding NES SIB changes. Alternatively, a WTRU may receive common indications as described in other examples herein. In one example, a P-RNTI may be used to indicate an NES SIB change indication. In another example, a new P-NES-RNTI may be used to provide an NES SIB change indication, which eliminates the need for a non-NES WTRU to decode paging and subsequent system information capture. In one example, a common indication may be transmitted using a MAC CE. In another example, a common indication may be transmitted via DCI using a group common RNTI, an NES RNTI, or another common RNTI. In another example, a common indication may be transmitted using a short message carried over the PDCCH using a P-RNTI.

[0238] A WTRU may capture an SIB that provides NES information for a configured set of cells. Alternatively, capturing this SIB may be optional, and if a common indication is used, it may contain all the information necessary to update the NES status. If an NES SIB is not scheduled, the WTRU may request the network to receive an NES SIB through dedicated signaling. The NES SIB may provide updates on the status of neighbor cell NES status. An NES status indication may be a cell that is turned ON or OFF with a (pre-configured) / indicated time delay.

[0239] WTRU identifies the NES indication from the NES SIB for the cell that is a candidate for its LTM (Long-Term Target) 1204.

[0240] The WTRU can remove LTM candidates that the network has indicated with a status OFF from its set of actively monitored LTM candidates.1205 If the group common signaling providing the NES status includes a turn-off indication for a SpCell, the WTRU can determine a suitable LTM candidate according to the following: The WTRU can select a suitable LTM target from among the activated and configured LTM candidates (for example, “activated” may mean that the WTRU has a valid TA for this cell, that the WTRU maintains DL synchronization, that the WTRU performs TRS tracking, and / or that the WTRU actively reports CSI). The selection of a suitable candidate may be through a second set of RSRP (RSRQ) thresholds configured by the network. If no cell satisfies the autonomous selection criteria, the WTRU may select the cell with the strongest signal quality, and / or the strongest signal quality criterion may be the RSRP, RSRQ associated with the target candidate's RS. The criteria may be part of the configuration.

[0241] WTRU can activate LTM candidate cells that are ON 1206. WTRU can report measurements of, for example, N best cells 1207. WTRU can perform LTM cell switching to selected cells 1208.

[0242] In some cases, the WTRU can autonomously determine the most suitable cell to switch over to. For example, the WTRU may attempt to autonomously trigger the LTM if it receives an indication that a PCell has been switched off due to the NES.1209

[0243] WTRU can attempt to autonomously trigger LTM if it receives an indication that one or more neighbor cells have been switched on.

[0244] The WTRU can select a subset of LTM candidate cells to consider for autonomous LTM. In one example, the subset may be determined based on one or more of the following: cells with valid TAs, cells with DL synchronization maintained by the WTRU, cells with TRS tracking performed by the WTRU, cells with CSI actively reported by the WTRU, cells with radio quality measurements exceeding a configured threshold, and / or an explicit list of cells.

[0245] A subset of cells may be selected so that those cells are ready for the WTRU to perform LTM at any time (for example, based on an explicit MAC CE). For example, if the WTRU has already performed a PDCCH ordered RA to obtain TA, or if the WTRU is explicitly configured to maintain DL sync or report CSI measurements.

[0246] For example, a WTRU may select a subset of cells based on current radio conditions, and the WTRU may need to trigger random access to target cells during LTM execution. In some cases, a WTRU may be configured with early TA capture using RAR (for example, a WTRU may be configured to perform early TA capture and receive TAs in RAR). In this case, the WTRU may respond to RAR (for example, using a provided grant) to complete LTM to the target cell.

[0247] A WTRU can attempt to perform a cell switch to the cell indicated as the one to be switched on, and a WTRU can perform random access after a specific time period. A WTRU can first trigger the measurement and / or DL ​​synchronization procedure before triggering the RA.

[0248] A WTRU may be pre-configured (either by RRC or in MAC CE) by indications of specific cells that should be included in a subset. This pre-configuration may include the TA to use, the uplink resources to use, such as a configured grant for sending an ACK (e.g., CG-PUSCH at a specific time), and specific RA resources. The WTRU may receive a time indication for this grant regarding the timing of receiving signaling indicating the NES state. The time indication may be pre-configured, sent with the indication, or determined based on the received indication.

[0249] The preferred target cells can be determined from a subset. This can be based on prioritization, for example, prioritizing cells within the DU or specific cells, the best radio quality measurement, for example, RSRP, and / or one or more cells with the largest number of beams exceeding the radio quality threshold.

[0250] Once a suitable candidate cell has been determined, the WTRU can perform LTM. For example, it can perform RRC reconstruction using the stored candidate configuration but without any explicit MAC CE.

[0251] One approach may involve LTM configuration updates based on common indications that update the NES state of a cell. Generally, a WTRU can receive configurations that enable dynamic updates of neighbor cell NES states using common signaling. For example, a configuration for a WTRU may be one or more of the following: the WTRU can be configured to receive one or more NES indications that can be provided in group common signaling; RRC preconfiguration may provide details of cell identification and NES state patterns; and / or the WTRU can be configured with a set of LTM candidates and measurements, procedures, and parameters associated with a particular NES state.

[0252] A WTRU may receive a common signaling that provides updates to one or more neighbor cell NES states. For example, this signaling may include one or more of the following: an NES state indication that can show cells that are turned ON or OFF with a (pre)configured / indicated time delay; one or more NES neighbor cell configuration IDs or mapping tables that allow the WTRU to associate the correct NES state with the relevant cell; and / or an index to a preconfigured set of neighbor cell states.

[0253] The WTRU can update the LTM configuration according to new NES status. For example, the WTRU can remove an LTM candidate that the network has shown an NES indication with status OFF from its set of actively monitored LTM candidates, and enable an LTM candidate that the network has shown an NES indication with status ON. The WTRU can update LTM candidate cell monitoring based on NES status, for example, CSI reporting which can update SSB or CSI-RS that are active in some of the candidates, DL / UL sync, L1 event trigger reporting which is a new MAC CE for L1 event reporting (for example, limited to active NES cells only), updating thresholds or L1 reporting criteria based on cell status, and / or updating the active BWP that should be used when triggering an LTM.

[0254] If the group common signaling providing the NES status includes a turn-off indication for the PCell, then one or more of the following may be applied: the WTRU may receive a network indication for an LTM switch to one of the candidates; the WTRU may perform an LTM switch to the network-indicated cell; and / or the WTRU may measure a subset of the LTM candidates and provide indications to the network. In this last option, the indications may be one or more of the following: an RRC measurement report, an L1 event trigger report (e.g., in MAC CE), or a CSI report, a report of the strongest (e.g., the strongest of a configurable number) cell to the network, and / or a specific set of cells (e.g., NES alternate cells).

[0255] Group / common signaling can enable additional benefits to the system, such as reduced signaling overhead. The NES status of a cell can be communicated using common signaling, and each WTRU can update its LTM configuration (e.g., active) based on the NES status. There may be identification of a preferred alternative cell for performing LTM before the cell is powered off.

[0256] One approach can involve SIB-based / group-common NES indication and implicit and / or conditional LTM. Generally, WTRUs can receive configurations that use common signaling to enable dynamic updates of neighbor cell NES states.

[0257] A WTRU can receive common signaling that provides updates to the NES state of one or more neighbor cells.

[0258] WTRU can update the LTM configuration according to the new NES state.

[0259] An implicit LTM trigger may exist. If the common signaling providing the NES state includes a turn-off indication for the SpCell, the WTRU will determine a suitable LTM candidate and autonomously perform the LTM cell switch to the selected cell.

[0260] In such cases where an implicit LTM trigger exists, the WTRU can select a suitable LTM target from a subset of LTM candidates. The subset may be cells that the WTRU maintains DL sync and / or UL sync (e.g., have a valid TA), which can imply that the cell is ready at any time and prepared for an LTM cell switchover. The subset may be cells with CSI reporting enabled. The subset may be a set of cells previously identified as LTM candidates in the case of an NES turn-off indication. The selection of a suitable target from the subset may be based on radio conditions, such as being the strongest cell within the selected subset or exceeding a threshold.

[0261] In the case of an implicit LTM trigger, if a suitable cell is selected, the WTRU can perform LTM without using a MAC CE trigger. If the WTRU does not yet have a DL / UL sync, the WTRU can perform RACH to the target cell. Otherwise, the WTRU can perform LTM in the same way as if the candidate configuration index had been received in MAC CE (for example, if successful).

[0262] In cases where there is an implicit LTM trigger, and it is not possible to select a suitable cell for the implicit LTM trigger, the WTRU can trigger the RLF or measurement report.

[0263] This approach can offer one or more benefits to the system, such as improved latency and reduced signaling when turning off cells. Using common signaling, HOs can be implicitly triggered for multiple WTRUs on a deactivated cell, avoiding the need to individually trigger WTRUs when a cell enters the NES "off" state.

[0264] As described herein, a higher layer may refer to one or more layers in a protocol stack, or a specific sublayer within a protocol stack. A protocol stack may consist of one or more layers in a WTRU or network node (e.g., eNB, gNB, or other functional entities), and each layer may have one or more sublayers. Each layer / sublayer may be responsible for one or more functions. Each layer / sublayer may communicate directly or indirectly with one or more of the other layers / sublayers. In some cases, these layers may be numbered, such as Layer 1, Layer 2, and Layer 3. For example, Layer 3 may consist of one or more of the Non-Access Layer (NAS), Internet Protocol (IP), and / or Radio Resource Control (RRC). For example, Layer 2 may consist of one or more of the Packet Data Convergence Control (PDCP), Radio Link Control (RLC), and / or Medium Access Control (MAC). For example, Layer 3 may consist of Physical (PHY) layer type operations. The higher the layer number, the higher it is relative to other layers (for example, Layer 3 is higher than Layer 1). In some cases, the examples above may be referred to as layers / sublayers themselves, regardless of their layer number, and may be referred to as higher layers as described herein. For example, from top to bottom, higher layers may refer to one or more of the following layers / sublayers, namely the NAS layer, RRC layer, PDCP layer, RLC layer, MAC layer, and / or PHY layer. Any reference herein to higher layers relating to a process, device, or system will refer to a layer higher than the layer of the process, device, or system. In some cases, references herein to higher layers may refer to functions or operations performed by one or more layers described herein.In some cases, references to higher layers in this specification may refer to information transmitted or received by one or more layers described herein. In some cases, references to higher layers in this specification may refer to configurations transmitted and / or received by one or more layers described herein.

[0265] While features and elements are described above in specific combinations (e.g., embodiments, methods, examples, etc.), those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. For example, there may be methods described in relation to the drawings for illustrative purposes, as disclosed herein, and those skilled in the art will understand that one or more features or elements from this method can be used alone or in combination with one or more features from other methods described elsewhere. In this specification, the symbol " / " (e.g., a forward slash) may be used to mean "and / or," for example, "A / B" may imply "A and / or B." As used herein, "a" and "an" and similar phrases should be interpreted as "one or more" and "at least one." Similarly, any term ending in the suffix "(s)" should be interpreted as "one or more" and "at least one." The term "may" should be interpreted as "for example, can," or should indicate that something "happens" or "can happen." Furthermore, the methods described herein can be implemented in computer programs, software, or firmware embedded in computer-readable media for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital multi-purpose disks (DVDs). A software-related processor can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method implemented by a wireless transceiver unit (WTRU), A step of receiving configuration information for one or more candidate cells, including cell identification for one or more candidate cells, from a first cell, wherein the one or more candidate cells are in an active network energy saving (NES) state. The steps include receiving L1 / 2 trigger mobility (LTM) measurement configuration information from the first cell for at least one cell from the one or more candidate cells, A step of receiving a first signaling message from the first cell, wherein the first signaling message includes the identification of at least one cell from the one or more candidate cells, and an indication of activation of a cell-off NES state for the identified at least one cell from the one or more candidate cells. The WTRU generates a measurement result for at least one candidate cell in the active NES state based on the LTM measurement configuration information, A step of sending an LTM measurement report message to the first cell, wherein the LTM measurement report message includes, for each measured cell, at least the measurement result and identification of the measured cell. A step of receiving a second signaling message from the first cell, wherein the second signaling message includes the identification of the second cell, and the second cell is a cell included in the measurement report message. In the WTRU, the step of switching from the first cell to the second cell, The WTRU sends a third signaling message to the second cell to confirm the successful switchover. A method for providing this.

2. The method according to claim 1, further comprising the step of receiving configuration information for one or more NES states from a network, wherein the one or more NES states include the active NES state and the cell-off NES state, and the configuration information for the cell-off NES state includes a time value indicating the duration for which the cell will be turned off.

3. After the WTRU receives the first signaling message, which includes an indication of activation of the cell-off NES state for at least one identified cell from the one or more candidate cells, and after the duration has elapsed, the WTRU generates an LTM measurement result for the cell included in the first signaling message. The method according to claim 2, further comprising:

4. The method according to any one of claims 1 to 3, wherein the first signaling message and the second signaling message are received in downlink control information (DCI).

5. The method according to any one of claims 1 to 4, wherein the measurement report message is sent in a media access control (MAC) control element (CE).

6. The method according to any one of claims 1 to 5, wherein the third signaling message is sent in a radio resource control (RRC) message.

7. The method according to any one of claims 1 to 6, wherein the first signaling message is a group common signaling message targeting a plurality of WTRUs.

8. The method according to any one of claims 1 to 7, wherein the first cell is a PCell.

9. The method according to any one of claims 1 to 8, further comprising the step of receiving a fourth signaling message from the network, wherein the fourth signaling message includes the identification of at least one cell from the one or more candidate cells, the identified at least one cell from the one or more candidate cells is in a cell-off NES state, and the fourth signaling message includes an indication of activation of the active NES state for the identified at least one cell from the one or more candidate cells.

10. The WTRU generates a measurement result for at least one of the one or more candidate cells identified in the fourth signaling message, based on the measurement configuration information. The method according to claim 9, further comprising:

11. A wireless transceiver unit (WTRU), wherein the WTRU comprises at least one processor and transceiver, and the at least one processor and transceiver are From the first cell, configuration information for one or more candidate cells, including cell identification for one or more candidate cells, is received, and the one or more candidate cells are in an Active Network Energy Saving (NES) state. From the first cell, receive L1 / 2 trigger mobility (LTM) measurement configuration information for at least one cell from the one or more candidate cells. A first signaling message is received from the first cell, the first signaling message includes the identification of at least one cell from the one or more candidate cells, and an indication of activation of a cell-off NES state for the identified at least one cell from the one or more candidate cells. Based on the LTM measurement configuration information, a measurement result is generated for at least one candidate cell in the active NES state. An LTM measurement report message is sent to the first cell, and the LTM measurement report message includes, for each measured cell, at least the measurement result and identification of the measured cell. A second signaling message is received from the first cell, the second signaling message includes the identification of the second cell, and the second cell is the cell included in the measurement report message. Switching from the first cell to the second cell, A third signaling message is sent to the second cell to confirm the successful switchover. A well-configured WTRU.

12. The WTRU according to claim 11, wherein the at least one processor and the transceiver are further configured to receive configuration information for one or more NES states from a network, the one or more NES states including the active NES state and the cell-off NES state, and the configuration information for the cell-off NES state includes a time value indicating the duration for which the cell will be turned off.

13. The WTRU according to claim 12, wherein the at least one processor and the transceiver are further configured to generate an LTM measurement result for the cell included in the first signaling message after the duration has elapsed, after receiving the first signaling message which includes an indication of activation of a cell-off NES state for the identified at least one cell from the one or more candidate cells.

14. The WTRU according to any one of claims 11 to 13, wherein the first signaling message and the second signaling message are received in downlink control information (DCI).

15. The measurement report message is sent in a media access control (MAC) control element (CE) according to any one of claims 11 to 14.

16. The third signaling message is a WTRU according to any one of claims 11 to 15, which is sent in a radio resource control (RRC) message.

17. The WTRU according to any one of claims 11 to 16, wherein the first signaling is a group common signaling message targeting a plurality of WTRUs.

18. The WTRU according to any one of claims 11 to 17, wherein the first cell is a PCell.

19. The WTRU according to any one of claims 11 to 18, wherein the at least one processor and the transceiver are further configured to receive a fourth signaling message from the network, the fourth signaling message comprising the identification of at least one cell from the one or more candidate cells, the identified at least one cell from the one or more candidate cells being in a cell-off NES state, and the fourth signaling message comprising the indication of activation of the active NES state for the identified at least one cell from the one or more candidate cells.

20. The WTRU according to claim 19, wherein the at least one processor and the transceiver are further configured to generate a measurement result for the at least one cell from the one or more candidate cells identified in the fourth signaling message, based on the measurement configuration information.

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