Wireless transmitting / receiving unit and method for performing same

Abstract

A wireless transmit / receive unit (WTRU) is configured with multiple condition handover and / or measurement report configurations. The WTRU activates or deactivates one or more of a plurality of configurations in accordance with various conditions such as changes in a combination of a primary cell (PCell), a currently active secondary cell (SCell) in a set of configurations of candidate L1 / L2 mobility cells, or in accordance with a specific change in a combination of currently active cells in a set of configurations of candidate L1 / L2 mobility cells. Conditional reconfiguration for updating the set of candidate L1 / L2 mobility cells may be performed. A list of mobility region indices may be included in the configuration, such as including an associated set of conditions for activating a particular region or a set of configurations to be activated when the indices are activated.

Description

[0001] This application is a divisional application of the invention patent application with the application date of July 10, 2023, application number 202380058592.X (international application number PCT / US2023 / 027268), and invention name “Method for managing measurement configuration using L1 / L2-based mobility”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Application No. 63 / 388,111 filed on July 11, 2022, U.S. Provisional Application No. 63 / 394,888 filed on August 3, 2022, and U.S. Provisional Application No. 63 / 465,115 filed on May 9, 2023, the entire contents of which are incorporated herein by reference. Background Art

[0004] A wireless transmit / receive unit (WTRU) can be configured with multiple conditional handover (HO) and / or measurement reporting configurations. The WTRU can be set to activate or deactivate various configurations based on one or more conditions. In 3GPP Release 18, the work item (WI) on "Further NR Mobility Enhancements" includes several objectives related to this context. Summary of the Invention

[0005] A wireless transmit / receive unit (WTRU) may include a processor configured to receive configuration information. For example, the configuration information may indicate a plurality of mobility candidate cells and a plurality of measurement configurations. The WTRU may activate a first measurement configuration from the plurality of measurement configurations based on the first cell being a current serving cell of the WTRU. The WTRU may be configured to determine that a second measurement configuration from the plurality of measurement configurations is to be deactivated based on the first cell being the current serving cell of the WTRU. The WTRU may receive Layer 1 or Layer 2 (L1 / L2) control signaling indicating that the WTRU is to perform mobility to a second cell. For example, the second cell may be one of the plurality of mobility candidate cells.

[0006] The WTRU may determine which measurement configurations of the plurality of measurement configurations to activate and which measurement configurations of the plurality of measurement configurations to not activate when performing mobility to the second cell based on the second cell being the WTRU's new serving cell and the mobility to the second cell resulting in activation of a third cell in the plurality of mobility candidate cells as a secondary cell. For example, the second cell may be a primary cell. Additionally, the second measurement configuration may be determined to be activated. The WTRU may perform one or more measurements associated with the second measurement configuration. The WTRU may transmit a measurement report via the second cell based on the measurements associated with the second measurement configuration. The plurality of measurement configurations may include a channel state information (CSI) reporting configuration.

[0007] The L1 / L2 control signaling includes a medium access control (MAC) control element (CE). The WTRU may be configured to receive the configuration information indicating the plurality of mobility candidate cells independently of the plurality of measurement configurations. The L1 / L2 control signaling may indicate a new special cell (SpCell) and an activated secondary cell (Scell). The WTRU may be configured to receive the plurality of measurement configurations and associations with one or more special cell (SpCell) / secondary cell (SCell) combinations. The WTRU may be configured to determine, based on the one or more SpCell / SCell combinations, which of the plurality of measurement configurations to activate and which of the plurality of measurement configurations to not activate when performing mobility to the second cell.

[0008] The WTRU may be configured to determine which of the plurality of measurement configurations to activate and which of the plurality of measurement configurations to deactivate when performing mobility to the second cell based on a combination of currently active secondary cells (SCells) in the plurality of mobility candidate cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0010] Figure 1B is an example of a method that can be used according to an embodiment of the present invention. Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system.

[0011] Figure 1C is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of an example radio access network (RAN) and an example core network (CN) used within the illustrated communication system.

[0012] Figure 1Dis an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of an additional example RAN and an additional example CN for use within the illustrated communication system.

[0013] Figure 2 An example of a basic handover scenario in NR is shown.

[0014] Figure 3 An example of conditional handover configuration and execution is shown.

[0015] Figure 4 An example of L1 / L2 inter-cell mobility using carrier aggregation (CA) is shown.

[0016] Figure 5 An example of L1 / L2 mobility zones is shown.

[0017] Figure 6 An example of dynamic activation of a conditional handover (CHO) configuration is shown.

[0018] Figure 7 An example of dynamic activation of a CHO configuration is shown.

[0019] Figure 8 An example of activating CHO / CPAC configuration according to the current SpCell is shown.

[0020] Figure 9 Another example of L1 / L2 mobility zones is shown.

[0021] Figure 10 A flow chart showing measurement configuration using L1 / L2 based mobility DETAILED DESCRIPTION

[0022] Figure 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. Communication system 100 may enable multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, 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-tailing unique word DFT-spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multi-carrier (FBMC).

[0023] like Figure 1AAs shown, the communication system 100 may include WTRUs 102a, 102b, 102c, 102d, the RAN 104 / 113, the CN 106 / 115, the public switched telephone network (PSTN) 108, the Internet 110, and other networks 112. However, it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include 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 watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated process chain environments), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a WTRU.

[0024] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CNs 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNodeB, a Home NodeB, a Home eNodeB, a gNB, a New Radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it should be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0025] Base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, one for each sector of the cell. In one embodiment, base station 114a may employ multiple-input, multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0026] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0027] More specifically, as noted 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, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​Uplink (UL) Packet Access (HSUPA).

[0028] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA) that may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0029] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

[0030] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access, for example, using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0031] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology 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 Enhanced Data rates for Evolution (EDGE), and GSM EDGE (GERAN).

[0032] Figure 1AThe base station 114b in the may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), and a roadway. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. Figure 1A As shown, base station 114b may have a direct connection to the Internet 110. Therefore, base station 114b may not need to access the Internet 110 via CN 106 / 115.

[0033] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions, such as user authentication. Although not described in Figure 1A Although not shown in the figures, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or Wi-Fi radio technology.

[0034] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0035] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0036] Figure 1B is a system diagram illustrating an exemplary WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0037] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors 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 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0038] The transmit / receive element 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It should be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0039] Although the transmit / receive element 122 Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0040] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0041] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from the speaker / microphone 124, keypad 126, and / or display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 may access information from and store data in any suitable type of memory, such as non-removable memory 130 and / or removable memory 132. 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 identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0042] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0043] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0044] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulation (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, and an activity tracker, etc. The peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0045] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (for transmission) and downlink (for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via signal processing performed by hardware (e.g., a choke) or by a processor (e.g., a separate processor (not shown) or by the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (for transmission) or downlink (for reception)) may be concurrent and / or simultaneous.

[0046] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0047] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0048] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0049] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0050] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c. The MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0051] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNode-B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0052] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0053] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0054] Even though the WTRU Figures 1A to 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may (eg, temporarily or permanently) employ a wired communication interface with a communication network.

[0055] In a representative embodiment, other network 112 may be a WLAN. A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or an interface with a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or out of the BSS. Traffic originating from outside the BSS and destined for a STA may reach the AP and be delivered to the STA. Traffic originating from a STA and destined for a destination outside the BSS may be transferred to the AP for delivery to the destination. Traffic between STAs within a BSS may be transferred through the AP, for example, where a source STA may transmit traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be transferred between (e.g., directly between) a source and destination STA using direct link setup (DLS). In certain representative embodiments, the DLS may utilize 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0056] When using 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may have a fixed width (e.g., a 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel may be the operating channel of the BSS and may be used by STAs to establish connections with the AP. In certain representative embodiments, such as in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. With CSMA / CA, STAs (e.g., each STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that particular STA may back off. One STA (e.g., only one station) may transmit in a given BSS at any given time.

[0057] High throughput (HT) STAs may communicate using a 40 MHz wide channel (eg, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels) to form a 40 MHz wide channel.

[0058] Very High Throughput (VHT) STAs can support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. 40 MHz and / or 80 MHz channels can be formed by combining contiguous 20 MHz channels. A 160 MHz channel can be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels (this is referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data passes through a segment parser that separates the data into two streams. Each stream is individually processed using an inverse fast Fourier transform (IFFT) and time domain processing. These streams are mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiving STA's receiver, the operations described above for the 80+80 configuration are reversed, and the combined data is passed to the media access control (MAC).

[0059] 802.11af and 802.11ah support sub-1 GHz operating modes. 802.11af and 802.11ah reduce the channel operating bandwidth and carriers used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah can support meter-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only for) certain bandwidths and / or limited bandwidth. MTC devices may also include batteries with battery life exceeding a threshold (e.g., to maintain very long battery life).

[0060] WLAN systems that support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be designated as a primary channel. The primary channel may have a bandwidth equal to the maximum 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 (which supports the minimum bandwidth operating mode) from among all STAs operating in the BSS. In the example of 802.11ah, for a STA (e.g., an MTC-type device) that supports (e.g., only) 1 MHz mode, the primary channel may be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, because a STA (supporting only 1 MHz operating mode) is transmitting to the AP, the entire available frequency band may be considered busy, even if most of the frequency band remains idle and potentially available.

[0061] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah ranges from 6MHz to 26MHz, depending on the country code.

[0062] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0063] The RAN 113 may include gNBs 180a, 180b, and 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. Each of the gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In one embodiment, the gNBs 180a, 180b, and 180c may implement carrier aggregation (CA). For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0064] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or Transmission Time Intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths).

[0065] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNBs 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNode-Bs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement dual connectivity (DC) principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may serve as mobility anchors for the WTRUs 102a, 102b, 102c and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0066] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0067] Figure 1DThe CN 115 shown in FIG may include at least one AMF 182 a, 182 b, at least one UPF 184 a, 184 b, at least one session management function (SMF) 183 a, 183 b, and possible data networks (DNs) 185 a, 185 b. While each of the aforementioned elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0068] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, terminating NAS signaling, and mobility management. The AMF 182a, 182b may use network slicing to customize CN support for the WTRUs 102a, 102b, 102c based on the type of services utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low-latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, and / or services for machine-type communication (MTC) access. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, or non-3GPP access technologies, such as Wi-Fi.

[0069] The SMF 183a, 183b may connect to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also connect to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notification. PDU session types may be IP-based, non-IP-based, Ethernet-based, and so on.

[0070] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0071] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via the N3 interface to the UPFs 184a, 184b and the N6 interface between the UPFs 184a, 184b and the local data networks (DNs) 185a, 185b.

[0072] Given that Figures 1A to 1D as well as Figures 1A to 1D As described herein, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more emulated devices (not shown): the WTRUs 102a-102d, the base stations 114a-114b, the eNodeBs 160a-160c, the MME 162, the SGW 164, the PGW 166, the gNBs 180a-180c, the AMFs 182a-182ab, the UPFs 184a-184b, the SMFs 183a-183b, the DNs 185a-185b, and / or any other devices described herein. The emulated devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulated devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0073] Emulated devices can be designed to implement one or more tests of other devices in a laboratory environment and / or in a carrier network environment. For example, one or more emulated devices can perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more emulated devices can perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulated device can be directly coupled to another device for testing purposes and / or can use over-the-air wireless communications to perform testing.

[0074] One or more emulated devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulated devices can be used in a test lab and / or in a test scenario where a wired and / or wireless communication network is not deployed (e.g., testing) to enable testing of one or more components. The one or more emulated devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) can be used by the emulated devices to send and / or receive data.

[0075] Figure 2 This section describes a handover scenario, for example, in New Radio (NR). In initial handover preparation, a WTRU (e.g., within the cell coverage of a source gNB) may receive information about roaming, access restrictions, and / or other mobility control information from the AMF, for example, at connection establishment and / or at the last timing advance (TA) update. The mobility control information may be provided by the AMF to the WTRU, the source gNB, and / or the target gNB. The source gNB may configure WTRU measurement procedures, and the WTRU may report to the source gNB based on the measurement configuration. The source gNB may decide to hand over the WTRU based on the received measurement results.

[0076] The source gNB may then issue a Handover Request message to the target gNB by passing a transparent Radio Resource Control (RRC) container with information for preparing the handover on the target side. This information may include at least one or more of the following: target cell ID, KgNB, the WTRU's C-RNTI (Radio Link Identifier) ​​in the source gNB, Radio Resource Management (RRM) configuration including WTRU inactivity time, basic AS configuration including antenna information and DL carrier frequency, current QoS flow to data radio bearer (DRB) mapping rules applied to the WTRU, SIB1 from the source gNB, WTRU capabilities and PDU session related information for different RATs, and may also include measurement information reported by the WTRU, including beam related information if available.

[0077] Admission control may be performed by the target gNB. If the WTRU is admitted, the target gNB may prepare for the handover using L1 / L2 and send a Handover Request Acknowledgement (HANDOVER REQUEST ACKNOWLEDGE) to the source gNB. The Handover Request Acknowledgement may include a transparent container to be delivered to the WTRU as an RRC message to perform the handover. Once the HANDOVER REQUEST ACKNOWLEDGE is delivered, handover execution may begin, allowing the WTRU to detach from the old cell and synchronize to the new cell.

[0078] The source gNB may trigger a WTRU handover by sending an RRCReconfiguration message to the WTRU, which contains information for accessing the target cell, such as the target cell ID, the new C-RNTI, and / or the target gNB security algorithm identifier for the selected security algorithm. The RRCReconfiguration message may also include the set of dedicated random access channel (RACH) resources, the association between RACH resources and synchronization signal blocks (SSBs), the association between RACH resources and WTRU-specific CSI reference signal (RS) configuration, common RACH resources, and system information of the target cell. In one application, buffered data and new data may be delivered from the UPF.

[0079] As the detach begins, the source gNB may transmit Early Transfer Status Transfer Data and an SN Status Transfer (SNSTATUS TRANSFER) message to the target gNB to convey the uplink PDCP SN receiver status and downlink PDCP SN transmitter status for DRBs to which PDCP status preservation (e.g., for Radio Link Control (RLC) AM) is applied. User data may be provided by the WTRU to the source gNB and then to the target gNB. The WTRU may synchronize to the target cell and complete the RRC handover procedure by transmitting an RRCReconfigurationComplete message to the target gNB.

[0080] During the handover completion portion of this scenario, a HO success signal may be transmitted from the target gNB to the source gNB. The source gNB may provide the target gNB with a SN state transfer. The target gNB may transmit a PATH SWITCH REQUEST message to the AMF to trigger the 5GC to switch the DL data path toward the target gNB and establish an NG-C interface instance toward the target gNB. The 5GC may switch the DL data path toward the target gNB. The UPF may transmit one or more "end marker" packets to the source gNB on the old path for each PDU session / tunnel and may then release any U-plane / TNL resources toward the source gNB. The AMF may acknowledge the PATH SWITCH REQUEST message with a PATH SWITCH REQUEST ACKNOWLEDGE message. Upon receiving the PATH SWITCH REQUEST ACKNOWLEDGE message from the AMF, the target gNB may transmit a WTRUCONTEXT RELEASE message to notify the source gNB of the successful handover. The source gNB may then release the radio and C-plane related resources associated with the WTRU context. Any ongoing data forwarding may continue.

[0081] NR Release 16 introduces the concepts of Conditional Handover (CHO) and Conditional Primary and Secondary Serving Cell (PSCell) addition / change (Continuous Packet Addition (CPA) / Continuous Packet Change (CPC), or collectively referred to as CPAC), which have the potential to reduce the likelihood of Radio Link Failure (RLF) and Handover Failure (HOF).

[0082] Traditional LTE / NR handovers are typically triggered by measurement reports, and nothing prevents the network from transmitting a HO command to the WTRU even if no measurement reports are received. For example, the WTRU may be configured with an A3 event (Neighbor's offset becomes better than SpCell), which triggers the transmission of a measurement report when the neighboring cell's radio signal level / quality (reference signal received power (RSRP), reference signal received quality (RSRQ), etc.) becomes better than the primary serving cell (PCell) or, in the case of DC, the PSCell. The A3 event may be triggered when the neighboring cell becomes better than a special cell (SpCell) by an offset. A special cell can be the primary serving cell of a master cell group (MCG) or secondary cell group (SCG). The offset can be positive or negative. The A3 event is typically used for intra-frequency or inter-frequency handover procedures. When the A2 event is triggered, the WTRU may be configured with measurement gaps for measuring inter-frequency objects and an A3 event for inter-frequency handovers. The A3 event provides a handover triggering mechanism based on relative measurement results. For example, the handover trigger mechanism may be configured to be triggered when the RSRP of the neighboring cell is stronger than the RSRP of the special cell.

[0083] The WTRU may monitor the serving cell and neighboring cells and may transmit measurement reports when conditions are met. When the network receives such reports, the network (current serving node / cell) may prepare a HO command. The HO command may be an RRC reconfiguration message with ReconfigurationWithSync, which is transmitted to the WTRU and executed by the WTRU, resulting in the WTRU connecting to the target cell.

[0084] In some examples, multiple handover targets are prepared. In addition, the WTRU may not perform CHO immediately. The WTRU may be configured with trigger conditions (such as a set of radio conditions), and if the trigger conditions are met, the WTRU may perform a handover to one of the targets.

[0085] The CHO command may be transmitted from the network while the radio conditions towards the current serving cell are still good, thereby reducing the risk of failure to transmit measurement reports (e.g., if the link quality to the current serving cell falls below an acceptable level when the measurement report is triggered in a normal handover), failure to receive a handover command (e.g., if the link quality to the current serving cell falls below an acceptable level after the WTRU has transmitted a measurement report but before it receives a HO command), etc. The WTRU may transmit a CHO command when the radio conditions towards the current serving cell start to get worse (e.g., deteriorate).

[0086] Figure 3Conditional handover configuration and execution are shown. At 302, the source node may transmit a CHO request 302 to the potential target node. At 304, the potential target node may transmit a CHO request ACK including an RRCReconfiguration to the source node. At 306, the WTRU may implement the CHO configuration. The source node may transmit an RRCReconfiguration to the WTRU, which is received by the WTRU. The triggering conditions for CHO may be based on the radio quality of the serving cell and neighboring cells, such as the conditions used to trigger measurement reports in traditional LTE / NR. In addition, the WTRU may be configured with a CHO with trigger conditions and associated HO commands of A1 (e.g., serving cell becomes better than a threshold), A2 (e.g., serving cell becomes worse than a threshold), A3 (e.g., neighbor's offset becomes better than SpCell), A4 (e.g., neighbor becomes better than a threshold), A5 (e.g., SpCell becomes worse than threshold 1 and neighbor becomes better than threshold 2), A6 (e.g., neighbor's offset becomes better than SCell), B1 (e.g., inter-RAT neighbor becomes better than a threshold), and / or B2 (e.g., PCell becomes worse than threshold 1 and inter-RAT neighbor becomes better than threshold 2). The A5 event may be triggered when the special cell becomes worse than threshold 1 and the neighbor cell becomes better than threshold 2. The A5 event may be used for intra-frequency or inter-frequency handover procedures. After the A2 event is triggered, the WTRU may be configured with measurement gaps and an A5 event for inter-frequency handover. The A5 event may provide a handover trigger mechanism based on absolute measurement results. The A5 event may be used to trigger a time critical handover when the current special cell becomes weak and it is necessary to change to another cell that may not meet the criteria for an A3 event handover. At 308, the WTRU may monitor the CHO conditions for the current cell, the serving cell, and / or the target cell candidates. At 310, when the A3 triggering condition is met, the WTRU may execute the associated HO command and switch its connection towards the target cell instead of transmitting a measurement report. At 312, the WTRU may transmit a CHO confirmation to the target node. And at 314, a path switch may be performed by the target node and a WTRU context release may be performed by the source node (see, e.g., Figure 2 10 to 12).

[0087] CHO can help prevent unnecessary re-establishment in the event of a radio link failure. For example, a WTRU may be configured with multiple CHO targets, and the WTRU may experience RLF before the triggering conditions for any of these targets are met. Conventional operation may result in an RRC re-establishment procedure that may also cause a significant interruption of the WTRU's bearers. However, in the case of CHO, if the WTRU eventually enters a cell associated with its CHO (e.g., a target cell may have been prepared for it) after detecting an RLF, the WTRU may directly execute the HO command associated with that target cell rather than continuing with the full re-establishment procedure.

[0088] CPC and CPA may be extensions of CHO in DC scenarios.In an embodiment, the WTRU may be configured with trigger conditions for PSCell change or addition, and when the trigger conditions are met, the WTRU may execute the associated PSCell change or PSCell add command.

[0089] In NR Release 17, inter-cell L1 / L2 mobility can manage beams in a CA scenario without supporting cell changes / additions. In Release 18, one of the envisioned objectives is to specify L1 / L2-based inter-cell mobility mechanisms and procedures to reduce mobility latency. In an embodiment, L1 / L2-based inter-cell mobility mechanisms and procedures to reduce mobility latency may be specified. Configuration and maintenance of multiple candidate cells may be specified to allow for rapid application of configurations for candidate cells (RAN2, RAN3). A dynamic switching mechanism among candidate serving cells (including special cells (SpCells) and / or SCells) based on L1 / L2 signaling (RAN2, RAN1) for potentially applicable scenarios may also be provided. An SpCell may refer to the PCell of a MSG and / or the PSCell of a secondary cell group (SCG), depending on whether the MAC entity is associated with a master cell group (MCG) or an SCG. The WTRU may be configured to receive multiple measurement configurations and associations with one or more special cell (SpCell) / secondary cell (SCell) combinations. L1 enhancements may be provided for inter-cell beam management, including L1 measurements and reporting, and beam indication [RAN1, RAN2]. RAN2 early involvement may be utilized, including further clarification of the possibility of interaction with dynamic handover. Timing advance management [RAN1, RAN2] and CU-DU interface signaling may also be provided to support L1 / L2 mobility (if required, [RAN3]). FR2-specific enhancements may not be excluded. Furthermore, the L1 / L2-based inter-cell mobility procedures are applicable to various scenarios, such as standalone deployments where the serving cell changes within a configured grant or cell group (CG), CA and NR-DC cases, intra-DU cases and intra-CU inter-DU cases (applicable to standalone deployments and CA when no new RAN interface is desired), intra-frequency, inter-frequency, FR1, FR2, source and target cells synchronized or asynchronous, and excluding inter-CU cases.

[0090] L1 / L2-based mobility was first introduced in NR Release 17, and inter-cell beam management in Release 17 addressed both intra-DU and intra-frequency scenarios. In this scenario, the serving cell remains unchanged (e.g., it is not possible to change the serving cell using L1 / L2-based mobility). In FR2 deployments, carrier aggregation is often used to utilize available bandwidth, for example, to aggregate multiple CCs in a frequency band. These CCs typically transmit using the same analog beam pair (gNB beam and WTRU beam). A WTRU may be configured with a number of TCI states (which may be quite large, e.g., 64) for receiving the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH). Each TCI state may include an RS or SSB that the WTRU references to set its beam. For Release 17, SSBs may be associated with non-serving PCIs. MAC signaling ("TCI state indication for WTRU-specific PDCCH MAC Control Element (CE)") may activate the TCI state for Coreset / PDCCH. PDCCH reception from non-serving cells is supported by a MAC CE indicating the TCI state associated with the non-serving PCI. MAC signaling ("TCI state activation / deactivation for WTRU-specific PDSCH") may activate a subset of (up to) eight TCI states for PDSCH reception. Downlink Control Information (DCI) may indicate a specific TCI state among the eight TCI states. Release 17 also supports "unified TCI states" with a different update mechanism (based on DCI) but without multiple transmit / receive points (TRPs). Release 18 may support unified TCI states with multiple TRPs.

[0091] For conventional Level 3 (L3), handover may be conditional on the WTRU first transmitting a measurement report using RRC signaling. In response, the network may provide additional measurement configuration and potentially a CHO configuration. With CHO, the network provides the configuration for the target cell after the WTRU reports using RRC signaling that the cell meets the configured radio quality criteria. For conditional handover, to reduce the handover failure rate due to the delay in transmitting the measurement report and then receiving the RRC reconfiguration, the network may provide the target cell configuration in advance as well as the measurement criteria that determine when the WTRU can trigger the CHO configuration. These L3 methods may incur a certain amount of delay due to the transmission of the measurement report and the reception of the target configuration, especially in the case of conventional (non-conditional) handover.

[0092] In an embodiment, L1 / L2 inter-cell mobility may be used to improve handover latency. In addition, L1 / L2 based inter-cell mobility may allow for rapid application of configurations for candidate cells, including dynamic switching between SCells and switching of PCells (e.g., switching roles between SCells and PCells), without performing RRC signaling. The inter-CU case is not included in Release 18 as this involves relocation of the PDCP anchor point and has been excluded from WI. An RRC based approach may be desirable, such as to support inter-CU handovers. One of the purposes of L1 / L2 is also to allow for immediate enabling of CA operations upon serving cell change.

[0093] Figure 4 An example of L1 / L2 inter-cell mobility operation using carrier aggregation (CA) is shown, whereby the set of candidate cells is configured by RRC and dynamic switching of PCell and SCell may be achieved using L1 / L2 signaling. The WTRU may be configured with cell 1 to cell 4 as candidate cells via RRC and activate PCell 1 and SCell 2. The WTRU may receive configuration information indicating multiple mobility candidate cells and multiple measurement configurations. The base station may perform L1 / L2 signaling for SCell activation / deactivation (intra-CU). CHO for PCell switching (intra-CU or inter-CU) may occur and the "set" of L1 / L2 candidates may be updated. The WTRU may activate a first measurement configuration of multiple measurement configurations based on the first cell being the current serving cell of the WTRU. The WTRU may also determine that a second measurement configuration of the multiple measurement configurations is to be deactivated based on the first cell being the current serving cell of the WTRU.

[0094] As the WTRU performs mobility from left to right, the WTRU may switch (e.g., dynamically) between cell 2 and cell 3. The higher frequency and higher bandwidth of cell 3 and cell 4 may be factors (or conditions) in determining the target cell to switch to. The WTRU may receive Layer 1 or Layer 2 (L1 / L2) control signaling indicating that the WTRU will perform mobility to a second cell, which is one of the multiple mobility candidate cells. As the WTRU continues to perform mobility to the right, the WTRU may switch (e.g., dynamically) the PCell to cell 2 and the SCell to cell 4. The WTRU may determine which measurement configurations of the multiple measurement configurations to activate and which measurement configurations of the multiple measurement configurations to not activate when performing mobility to the second cell (e.g., the second cell is the primary cell) based on the second cell being the WTRU's new serving cell and the mobility to the second cell resulting in activation of a third cell in the multiple mobility candidate cells as a secondary cell. The second measurement configuration may also be determined to be activated. The WTRU may be configured to determine, based on the one or more SpCell / SCell combinations, which of the plurality of measurement configurations to activate and which of the plurality of measurement configurations to deactivate when performing mobility to the second cell (e.g., PCell 1 to PCell 2). The WTRU may also be configured to determine, based on a combination of currently active secondary cells (SCells) in the plurality of mobility candidate cells, which of the plurality of measurement configurations to activate and which of the plurality of measurement configurations to deactivate when performing mobility to the second cell.

[0095] As discussed herein, Release 18 does not introduce support for inter-CU handover using L1 / L2 signaling. Therefore, regular or conditional handover can be employed to at least cover this scenario. Regular or conditional handover can be employed to support any mobility from any specific L1 / L2 mobility zone to another mobility zone.

[0096] Figure 5 An example of an L1 / L2 mobility zone 500 is shown. L1 / L2 inter-cell mobility may be deployed in certain areas. The network may define a zone with a set of multiple candidate L1 / L2 mobility cells. Furthermore, the network may divide the network deployment into multiple L1 / L2 mobility zones for other reasons, such as cell planning, or due to limitations on the maximum number of cell configurations that can be stored simultaneously in a WTRU. The network may define a contiguous zone with multiple cells (e.g., cells that are not candidate L1 / L2 mobility cells).

[0097] Since L1 / L2 inter-cell mobility may be intended to cover a much larger geographical area than conventional handover without any RRC reconfiguration signaling (e.g., a WTRU may move between more than one PCell without RRC reconfiguration), this may have a knock-on effect in terms of the amount of RRC configuration used to enable the WTRU to move around the L1 / L2 mobility area in order to support mobility outside the area. With conventional L3 mobility, the network may typically provide measurement configurations and conditional handover configurations based on the PCell currently serving the WTRU and potential target cells that are neighbors of the serving PCell. If a PCell change occurs due to a handover or conditional handover, the measurement configurations may be updated through RRC signaling, and potentially a new CHO configuration may be provided.

[0098] If L1 / L2 signaling can be used to dynamically switch the serving cell, but RRC signaling is still used to update the measurement configuration and conditional handover configuration, this may limit the effectiveness of the dynamic switching mechanism because the delay in performing the RRC signaling may be significant.

[0099] In an embodiment, it may be possible to pre-configure a number of measurement configurations and conditional handover configurations so that the WTRU can be equipped to perform measurements and handover to a cell outside of the configured L1 / L2 mobility area; for example, for the case where the WTRU moves into the coverage of another CU. However, there may be a limit to the number of CHO configurations and measurement objects that can be configured simultaneously in the WTRU. This may be partly due to limiting the complexity of the WTRU (in terms of the number of parallel measurements and evaluation conditions), but may also be designed to limit the amount of resources that the network reserves for any given WTRU - in the case of conditional handover, the network may reserve resources on the target cell in anticipation of the WTRU meeting the conditions and performing CHO. If the network expects to configure many CHOs, this also means that the amount of resources that may have to be reserved in the network (in potential target cells) may become unacceptably large.

[0100] In Release 18, enhancements to the CPAC targeted in the WI identified above are envisioned. Mechanisms and procedures for NR-DC are specified, whereby cell groups (e.g., SCGs) are selectively activated via L3 enhancements. Furthermore, it is envisioned to allow subsequent cell group changes after a CG change without the need to reconfigure and re-initiate CPC / CPA (RAN2, RAN3, RAN4). A coordinated RRC modeling approach may be considered to minimize workload in RAN2.

[0101] The intent of Release 18 WI appears to be to allow CPC / CPA configuration to remain active after CPC / CPA has been triggered. Currently, when reconfiguration is triggered, the WTRU may release any currently configured CPA / CPC configuration, and the network may establish a new CPA / CPC configuration. This may also be the case with CHO. Release 18 means that CPA / CPC is resolved but CHO / MGC is not. However, it is envisioned that similar issues may exist with CHO.

[0102] The WTRU may be configured with a set of multiple candidate target cells, which may be selected using Figure 4 The WTRU may store measurement and CHO configurations that it will use across an entire area of ​​potential L1 / L2 mobility cells and activate those configurations when it is in the appropriate area.

[0103] As generally discussed herein, unless otherwise specified, "measurement" refers to a measurement object and associated reporting configuration as in legacy NR (e.g., when reporting conditions are met, a measurement report can be transmitted). Furthermore, unless otherwise specified, "CHO ​​configuration" generally refers to a measurement object and associated reporting configuration for CHO (e.g., when reporting conditions are met, an associated CHO can be performed). However, certain measurement objects may be associated with multiple reporting configurations (whether for legacy measurement report triggering or for CHO).

[0104] Figure 6 An example of dynamic activation of a conditional handover (CHO) configuration 600 is shown. Figure 6In the example of L1 / L2 in a WTRU, signaling for Scell ​​activation / deactivation (intra-CU), CHO for PCell handover (e.g., intra-CU or inter-CU), and updating the "set" of L1 / L2 candidates may be performed. In this example, the network may provide four cell configurations. In this example, the set of candidate L1 / L2 mobility cells (e.g., cell 1 to cell 4) may be configured via RRC signaling. For example, the WTRU may receive four cell configurations indicating cell 1 to cell 4 as multiple mobility candidate cells and multiple measurement configurations. The WTRU may receive multiple measurement configurations (e.g., for cell 1 to cell 4) via RRC signaling. The WTRU may activate a first measurement configuration of the multiple measurement configurations based on the first cell (e.g., cell 1 being the current serving cell of the WTRU (e.g., cell 1 being activated as the PCell and cell 2 being activated as the SCell). In some cases, "serving cell" may refer to a primary cell, and "serving cell" may refer to a primary cell and a secondary cell. In some cases, "serving cell" may refer to a secondary cell. In other cases, "serving cell" may be used to refer to a set of one or more cells including a primary cell and all secondary cells. In some cases, a "primary serving cell" may include a primary cell, and a "secondary serving cell" may include a secondary cell. Figure 6 In the example, the WTRU is using cell 1 as the current serving cell.

[0105] The WTRU may be configured to determine that a second measurement configuration of the multiple measurement configurations is deactivated based on the first cell being the current serving cell of the WTRU. For example, cell 6 may be deactivated based on cell 1 being the current serving cell. The deactivation of cell 6 may occur for many reasons. For example, the distance between cell 1 and cell 6 may be too large for both cell 1 and cell 6 to be activated simultaneously. That is, cell 1 as a PCell and cell 6 as an SCell may not be so efficient because cell 6 may not be able to act as a good secondary cell due to its distance from cell 1. As an example, a secondary cell may include a cell operating on a primary frequency or a secondary frequency, which may be configured once an RRC connection is established and which may be used to provide additional radio resources to the WTRU. Providing additional radio resources to a WTRU that is too far from a cell may be difficult.

[0106] exist Figure 6In

[15] , L1 (e.g., DCI activation unified TCI state) or L2 (e.g., MAC CE) signaling may be used to dynamically switch the roles of the four pre-configured cells. The WTRU may receive Layer 1 or Layer 2 (L1 / L2) control signaling indicating that the WTRU will perform mobility to a second cell, which is one of the multiple mobility candidate cells. For example, "cell" may refer to a PCell, an SCell, a mobility candidate cell, an activated cell, a deactivated cell, a first cell, a second cell, a third cell, a fourth cell, a fifth cell, an nth cell, or any other cell. The WTRU performing mobility may include the WTRU moving in a certain direction. The WTRU performing mobility may include predicting, estimating, measuring, and / or calculating the WTRU's speed, direction, acceleration, and / or one or more locations. For example, if the WTRU is moving to the right, the WTRU, Layer 1, Layer 2, and / or Layer 3 may estimate where the WTRU will be within a given amount of time and activate required measurement configurations and deactivate unrequired measurement configurations. The location of the WTRU within the cell (e.g., the area of ​​the cell where the WTRU is located) can also be used to determine which measurement configurations are activated and deactivated. Figure 6 In the example, when the WTRU is located at the leftmost side of cell 1, the measurement configuration associated with cell 4 may be deactivated because cell 4 is towards the rightmost side of cell 1. When the WTRU is in the middle of cell 1, the measurement configuration associated with cell 3 may be activated because cell 3 is located just above (e.g., close to) the center of cell 1.

[0107] The WTRU may determine which measurement configurations of the plurality of measurement configurations to activate and which measurement configurations of the plurality of measurement configurations to not activate when performing mobility to the second cell, the second cell being a primary cell, based on the second cell being a new serving cell for the WTRU and the mobility to the second cell resulting in activation of a third cell of the plurality of mobility candidate cells as a secondary cell, wherein the second measurement configuration is determined to be activated. For example, Figure 6 In the example, the WTRU performs mobility from PCell 1 to PCell 2, which results in activation of cell 4 as a secondary cell (SCell 4), where the secondary cell was previously cell 2. Radio Resource Control (RRC) may be the highest layer in the control plane of the access stratum (AS). The RRC may transfer messages of the non-access stratum (NAS) located above the RRC layer. Additionally, in an embodiment, the network may provide one or more (two in this example) conditional handover configurations regarding the target cell. The WTRU may be configured to determine which of the multiple measurement configurations to activate and which of the multiple measurement configurations to not activate when performing mobility to the second cell based on a combination of currently active secondary cells (SCells) in the multiple mobility candidate cells.

[0108] As of Release 17 of the 3GPP standard, when multiple conditional handover configurations are provided, the WTRU stores these conditional handover configurations and evaluates the triggering conditions in parallel. With the proposed approach, these CHO configurations may not become active immediately upon configuration (e.g., a flag included in the measurement / CHO configuration that may store the relevant configurations) and may be activated in one or more ways (such as using explicit L1 / L2 signaling indicating activation of the CHO or measurement configuration). Additional activation examples may include when a cell becomes a PCell, when a SCell (e.g., or a set of SCells) is activated, when a SCell (e.g., or a set of SCells) is deactivated, when a PCell / SCell combination becomes active or is deactivated, and upon certain changes in the combination (e.g., a change from PCell 1 -> PCell 2 activates the configuration, but a change from PCell 3 -> PCell 2 may not activate the configuration).

[0109] In an embodiment, a similar mechanism may be employed to deactivate an active CHO or measurement configuration.Other mechanisms may be employed to release / delete an active or inactive CHO or measurement configuration.

[0110] For example, an embodiment may be used in the context of an L3 handover. In an embodiment, a CHO or CPAC configuration may be provided but not activated until a SpCell and / or one or more Scells become active, regardless of whether L1 / L2 triggered mobility is used. In an embodiment, the WTRU may perform a CPC-based configuration on the active configuration of the current serving cell. In an embodiment, the WTRU may activate and begin evaluating a stored CPC configuration, which is associated with a new serving cell, for example. In an embodiment, the procedures associated with cell changes activated or triggered using explicit L1 / L2 commands may also be applicable to cell changes using L3 RRC reconfiguration or CHO, CPC, or CPA. In some cases, the WTRU may determine that a second measurement configuration of the multiple measurement configurations is deactivated based on the first cell being the current serving cell of the WTRU.

[0111] The CHO configuration 1 may be provided with a target cell 5 and a measurement event for triggering CHO, such as CondEvent A3 (e.g., the offset of the neighbor becomes better than SpCell) or CondEvent A5 (e.g., SpCell becomes worse than Threshold 1 and the neighbor becomes better than Threshold 2). The network may not know in which direction the WTRU will move, so the network may establish targets in more directions around the WTRU (e.g., left, right, front, back, up, down). For this reason, even if the WTRU eventually moves to Figure 6, but cell 5 (located on the upper left) is still the target cell. The WTRU may be configured to activate CHO configuration 1 based on cell 1 being the PCell. As the WTRU performs mobility from left to right, the WTRU may switch (e.g., dynamically switch) the SCells between cell 2 and cell 3. As the WTRU continues to move to the right, the WTRU may switch (e.g., dynamically switch) the PCell from cell 1 to cell 2 and the SCell from cell 2 to cell 4.

[0112] The WTRU may perform one or more measurements associated with the second measurement configuration. Figure 6 In the example, similar to CHO configuration 1, CHO configuration 2 may be provided with target cell 6 and measurement events for triggering CHO. CHO configuration 2 may also be activated based on cell 2 being a PCell (e.g., or alternatively, a combination of PCell 1 and SCell 4 may activate CHO configuration 2). The WTRU may evaluate CHO based on an associated combination of active cells, rather than evaluating all configured CHOs in parallel. This may reduce processing overhead in the WTRU, allowing relevant measurements and evaluations to be performed based on the WTRU's location within the L1 / L2 mobility area. This may also reduce resource usage in the network. The network may not need to reserve resources on all configured target CHO cells, but may reserve resources based on the activated CHO configuration. For example, because the network may control the combination of active cells used by the WTRU (e.g., using L1 / L2 signaling), the network also controls the content of the target CHO cells and the currently active CHO configuration in the WTRU. The same or similar methods may also be used to control measurement objects and measurement reports for a normal handover. The WTRU may transmit measurement reports via the second cell based on the measurements associated with the second measurement configuration. For example, instead of or in addition to one or more CHO configurations, one or more measurement objects may be configured for measurement reporting and associated with one or more L1 / L2 controlled cell combinations. Additionally, carriers and / or cells (e.g., neighboring carriers and cells) currently being measured by the WTRU may be associated with L1 / L2 controlled cell combinations.

[0113] Activation of the measurement configuration and / or conditional reconfiguration may be based on any "condition" that indicates that the WTRU may be located within an L1 / L2 mobility area or within an area corresponding to a set of cells with pre-configured measurements or CHO / CPAC. These conditions may include which PCells and / or SCells are activated, and may include situations where there may be no active SCells and / or SCells may be deactivated for power conservation reasons.

[0114] In each instance of "X" and "Y" with at least one "mobility area index", a "mobility area index" may be introduced and configured. In an embodiment, "X" may include anything that may be activated / deactivated based on the location of the WTRU, such as: TCI state, non-serving PCI (e.g., within "NumberOfAdditionalPCI"), PCell / SCell combination, active bandwidth part (BWP), SCell activation state, measurement event trigger conditions being met, DL synchronization trigger for a candidate cell, RA ordered by a PDCCH towards a candidate cell, and / or enabling of radio link monitoring (RLM) or beam failure detection (BFD) on a target cell. In some examples, if the TCI state associated with a non-serving PCI is activated, then that PCI may be activated.

[0115] "Y" may include anything that supports measurement / mobility, such as configured measurement configurations, configured conditional reconfiguration and / or channel state information (CSI) reporting configurations, BFR configurations, and / or neighbor carrier / cell lists. Configured measurement configurations may include L3 measurement objects, L1 or L3 measurement events, CSI measurement configurations, and / or L1 or L3 measurement RS configurations (e.g., SSB or CSI-RS resources for the current or neighboring cell). Configured measurement configurations may include PCI or logical ID, SMTC location, frequency location, and / or SCS.

[0116] Based on the above, it is contemplated that examples of possible behaviors may include, for example, that if "X" is activated, any "Y" with the same "mobility area index" configured for X is also activated. In some examples, if there is no activated "X" with the same "mobility area index", then Y may be deactivated. In some examples, explicit activation / deactivation or switching of the "mobility area index" may occur, which may activate / deactivate the corresponding X and / or Y.

[0117] An example of a "mobility area index" may be one or more indices or identifiers that associate "X" (e.g., anything that can be activated / deactivated based on the WTRU's location) with "Y" (e.g., anything that supports measurement / mobility). For example, the WTRU may be configured with one or more measurement configurations, each with an index. Additionally, the WTRU may be configured with one or more conditions (e.g., SpCell / SCell combinations) and / or a list of one or more indices that identify measurement configurations that are enabled when the one or more conditions are met. Each of the configured conditions may be associated with the same or a different subset of measurement configurations. In this way, the measurement configuration may not need to be repeated for every possible SpCell / SCell combination, but each of the combinations for which the measurement configuration applies (e.g., an SpCell / SCell combination configured as an L1 / L2 mobility candidate configuration) may use an index or identifier to reference the measurement configuration (e.g., configured in a list or structure independent of the L1 / L2 mobility candidate configuration). Additionally, this also allows for configuring (eg, via RRC) more measurements than would be applicable to any given SpCell / SCell combination (eg, activated or triggered by a MAC CE).

[0118] Figure 7An example of dynamic activation of a CHO configuration 700 is shown. In this example, the first set of L1 / L2 mobility candidate cells consists of cell 1, cell 2, cell 3, and cell 4, and the second set of L1 / L2 mobility candidate cells consists of cell 5, cell 6, cell 7, and cell 8. At 704, one or more CHO configurations can be configured, but for the purposes of this illustration, one configuration is shown. The CHO configuration includes a target PCell configuration, but may also include a target PCell and SCell configuration (e.g., PCell 1 and SCell 3). The CHO configuration may also include a target set of L1 / L2 mobility candidate cells, that is, a set of L1 / L2 mobility candidate cells that can be dynamically controlled using L1 / L2 signaling after successful CHO completion. In some cases, the L1 / L2 control signaling may include a medium access control (MAC) control element (CE). This L1 / L2 control signaling may indicate a new special cell (SpCell) and an activated secondary cell (Scell). RRC and NAS messaging functions may be used to exchange signaling between the WTRU and the gNB. CE may be a special MAC structure that carries special control information. MAC CE may operate between the UE (MAC) and the gNB (MAC) for fast signaling communication exchange without involving upper layers. The WTRU may activate a first measurement configuration (e.g., PCell 1, SCell 3) from a plurality of measurement configurations based on the first cell being the WTRU's current serving cell. The WTRU may also determine that a second measurement configuration (e.g., measurement configurations associated with cell 2, cell 4, through cell 8) from the plurality of measurement configurations is to be deactivated based on the first cell being the WTRU's current serving cell.

[0119] At 706, the CHO trigger may use one of the existing measurement events such as event A3 or event A5. Alternatively, CHO may utilize one or more new measurement events. When cell 5 becomes an SCell, a CHO evaluation may be triggered (or activated), which means that the WTRU may have reached the boundary between cell 1 and cell 2 and should therefore begin evaluating the conditions for handover to the target cell 2. In some examples, the CHO trigger itself may be the activation of a specific combination of cells (in this example, the activation of SCell 5) or the activation of any condition related to the mobility areas explained previously. At 708, CHO may be performed and PCell 1 may be dynamically switched to PCell 2 and SCell 5 may be dynamically switched to SCell 6. As the WTRU continues to perform mobility to the right, dynamic switching may continue to occur for secondary cells (e.g., cell 7 and then cell 8) and primary cells.

[0120] In an embodiment, the criteria for activating or deactivating a measurement or CHO configuration may be associated with a specific transition rather than a static configuration. For example, a change of SCell from cell 3 to cell 5 may not trigger a specific configuration, but a change of SCell from cell 4 to cell 5 may activate the specific configuration. Therefore, the activation takes into account the current cell configuration and the previous cell configuration. The WTRU may determine which measurement configurations of the multiple measurement configurations to be activated and which measurement configurations of the multiple measurement configurations to not be activated when performing mobility to the second cell, which is a primary cell, based on the second cell being the new serving cell of the WTRU and the mobility to the second cell resulting in activation of a third cell in the multiple mobility candidate cells as a secondary cell.

[0121] In an embodiment, the WTRU may transmit an indication to the network whenever the activation state of a CHO or measurement configuration changes (e.g., when the configuration is activated, when the configuration is deactivated, when the configuration is released). In some cases, the measurement configuration may include a channel state information (CSI) reporting configuration.

[0122] Figure 8 An example diagram 800 is shown based on the current SpCell activation CHO / CPAC configuration. Figure 8 As shown, based on one or more measurement events, the WTRU may be configured with multiple CHO (e.g., or CPC) target cells. When performing CHO (e.g., or CPC) towards a new SpCell, the WTRU may start evaluating stored CHO (e.g., or CPC) configurations, which may potentially apply to the same target cell or may apply to different target cells. The WTRU may be configured to receive multiple measurement configurations and associations with one or more special cell (SpCell) / secondary cell (SCell) combinations. The WTRU may be configured to determine which of the multiple measurement configurations will be activated and which of the multiple measurement configurations will not be activated when performing mobility to the second cell based on the one or more SpCell / SCell combinations and / or based on a combination of currently active secondary cells (SCells) in the multiple mobility candidate cells.

[0123] The WTRU may be configured with conditional triggers for cell 1 to cell 2 and cell 1 to cell 3. The WTRU may also be configured with conditional triggers for cell 2 to cell 3 and cell 3 to cell 2. The WTRU may receive configuration information indicating multiple mobility candidate cells and multiple measurement configurations. The WTRU may be configured by the network with two conditional triggers targeting cell 2, such as, for example, one condition to be used on cell 1 and another condition to be used on cell 3. Similarly, the WTRU may be configured with two conditional triggers targeting cell 3, such as, one condition to be used on cell 1 and another condition to be used on cell 2.

[0124] The WTRU may be configured with a conditional trigger for moving to cell 2 with a different offset depending on whether the WTRU is currently on cell 1 or cell 3. Similarly, the conditional trigger for moving to cell 3 may be configured by the network with a different offset depending on whether the WTRU is currently on cell 1 or cell 2.

[0125] The WTRU may trigger reconfiguration to cell 2. The WTRU may activate evaluation of conditional triggers for performing mobility from cell 2 to cell 3 and / or from cell 2 to cell 1. The WTRU may activate a first measurement configuration from a plurality of measurement configurations based on the first cell being the WTRU's current serving cell. The WTRU may determine that a second measurement configuration from the plurality of measurement configurations is to be deactivated based on the first cell being the WTRU's current serving cell.

[0126] The CHO or CPC configuration can be independent, for example based on the current RRC signaling structure. In some examples, the conditional trigger configuration can be as follows:

[0127]

[0128]

[0129] In the above embodiment, each CHO / CPAC configuration is (preferably) provided with an event type and offset / threshold / hysteresis / time to appropriately trigger the parameters. In the event of triggering an active CHO or CPAC to a new SpCell, the WTRU may activate a new conditional trigger configuration for the CHO, CPA, or CPC associated with the new SpCell.

[0130] It may be desirable to reuse the same conditional trigger configuration for multiple cells and provide possibly different parameters. A conditional trigger (for CHO, CPC, CPA) may be provided for a specific target cell, such as conditional event A3. With the exception of the offsets to be used, all configurations may be the same for the target cell, regardless of the current cell. The WTRU may then receive the conditional trigger configuration for the specific cell and further receive a list of offsets to be used depending on the current SpCell.

[0131] In some embodiments, the WTRU may use the first condition to set the initial conditions for the applied measurement configuration and details on how to further update the configuration using the second condition.

[0132] In some embodiments, the WTRU may determine a first configuration based on a first condition (e.g., a new SpCell / SCell combination) and may subsequently update the configuration based on a second condition (e.g., SCell activation / deactivation state). For example, the WTRU may be configured to perform an L1 / L2 triggered handover and apply a configuration using cell 1 as the PCell and cell 2 and / or cell 3 as the SCell. Additionally, cell 2 and cell 3 may be configured as L1 / L2 handover target cells (e.g., target SpCells provided in the L1 / L2 handover candidate configuration). The initial state of the SCell may be deactivated. Based on this, the WTRU may apply a first measurement configuration associated with measurements and / or reporting of cell 2 and cell 3 based on the fact that these cells are L1 / L2 handover target cells. Subsequently, the WTRU may receive an indication to activate one or both of cell 2 and cell 3. The WTRU may then apply the measurement configuration associated with reporting the active SCell. For example, the WTRU may be configured with one type of measurement resource (e.g., an SSB measurement resource configuration) and / or the WTRU may be configured to perform reporting using a first type of reporting (e.g., a CSI report containing information for L1 / L2 handover preparation) for use when a cell is configured as an SCell but is not active. In some cases, the WTRU may receive Layer 1 or Layer 2 (L1 / L2) control signaling indicating that the WTRU will perform mobility to a second cell, which is one of a plurality of mobility candidate cells. The WTRU may also determine which measurement configurations of the plurality of measurement configurations to activate and which measurement configurations of the plurality of measurement configurations not to activate when performing mobility to the second cell (e.g., the second cell is a primary cell) based on the second cell being a new serving cell for the WTRU and the mobility to the second cell resulting in activation of a third cell of the plurality of mobility candidate cells as a secondary cell. The WTRU may determine the second measurement configuration to activate.

[0133] The WTRU may be configured with a second type of measurement resource (e.g., a CSI-RS measurement resource configuration) and / or the WTRU may be configured to perform reporting using a second type of reporting (e.g., a CSI report for reporting the active SCell) when the cell is an activated SCell. Thus, when L1 / L2 handover occurs, the WTRU may determine to apply the first type of measurement configuration and / or the first type of reporting based on the SpCell / SCell combination (e.g., the SpCell / SCell combination configured by RRC and then activated / triggered using L1 / L2 signaling such as a MAC CE). Subsequently, when the SCell activation state changes (e.g., when a second MAC CE is received that changes the activation / deactivation state of the configured SCell), the WTRU may determine to apply the second type of reporting and / or the second type of reporting. Alternatively or additionally, the WTRU may use any of the previously listed conditions (e.g., "X") as the first condition and / or the second condition. The first condition may be a condition that applies when performing a handover (e.g., an L1 / L2 triggered handover) using a specific condition (e.g., an SpCell / SCell combination pre-configured by RRC and triggered by a MAC CE), and the second condition may be any subsequent configuration change (e.g., SCell activation / deactivation by a MAC CE). The WTRU may perform one or more measurements associated with a second measurement configuration and transmit a measurement report via the second cell based on the measurements associated with the second measurement configuration.

[0134] Figure 9An example of an L1 / L2 mobility area 900 is shown. A WTRU (as represented by the solid black dot in the center of the mobility area) may be surrounded by L1 / L2 mobility candidate cells. The WTRU may be configured to receive configuration information indicating multiple mobility candidate cells independently of the multiple measurement configurations. That is, L1, L2, and / or Layer 3 (L3) may transmit information related to the mobility candidate cells separately from the multiple measurement configurations. "Independently" may mean separately, in different locations, in different signals, and / or in the same signal but in different locations, sub-blocks, and / or portions of the signal. Another set of cells may have active measurements determined based on active Lower Layer Triggered Mobility (LTM) candidates. Lower layers may include the physical layer (PHY) and the medium access control (MAC) layer. LTM may enable serving cell changes via L1 / L2 signaling while maintaining upper layer configurations and / or minimizing changes to lower layer configurations. This may help reduce latency, overhead, and interruption time during handover. LTM may support both distributed intra-unit (DU) and central unit (CU)-inter-DU mobility. During LTM, the user plane may continue with the target cell when possible (e.g., within a DU) without requiring a reset to avoid data loss and additional delays in data recovery. A set of cells may have configured measurements that are not currently being used (e.g., due to the WTRU's location, trajectory, direction and / or speed of movement, proximity to the cell).

[0135] Figure 10 A flow chart illustrating an example process 1000 performed by a WTRU for performing measurement configuration using L1 / L2-based mobility is shown. At 1002, the WTRU may receive configuration information for a plurality of L1 / L2 mobility candidate cells. The configuration information may indicate the plurality of mobility candidate cells and a plurality of measurement configurations. In some examples, the WTRU may be configured to receive the plurality of measurement configurations and their association with one or more special cell (SpCell) / secondary cell (SCell) combinations.

[0136] At 1004, the WTRU may receive one or more measurement configurations and CSI reporting configurations and associations with one or more SpCell / SCell combinations from the network (e.g., independent of the L1 / L2 candidate cells). For example, the WTRU may receive a first measurement configuration based on the first cell being a current serving cell for the WTRU. The WTRU may activate the first measurement configuration from a plurality of measurement configurations based on the first cell being the current serving cell for the WTRU. The WTRU may be configured to determine that a second measurement configuration is deactivated based on the first cell being the current serving cell for the WTRU. In some examples, the measurement configuration includes a channel state information (CSI) reporting configuration.

[0137] At 1006, the WTRU may receive L1 / L2 control signaling indicating the new SpCell and the activated Scell, and the WTRU may apply the associated candidate cell configuration. The layer 1 or layer 2 (L1 / L2) control signaling may indicate that the WTRU will perform mobility to at least a second cell, where the second cell is one of a plurality of mobility candidate cells (e.g., as indicated by the configuration information received at 1002). In some examples, the L1 / L2 control signaling may include (e.g., or be provided via) a medium access control (MAC) control element (CE). In some examples, the L1 / L2 control signaling may indicate the new special cell (SpCell) and the activated secondary cell (Scell).

[0138] At 1008, based on the SpCell / SCell combination, the WTRU may determine one or more measurement configurations and CSI reporting configurations to use. For example, the WTRU may be configured to determine which measurement configurations of the plurality of measurement configurations to activate and which measurement configurations of the plurality of measurement configurations to not activate when performing mobility to the second cell (e.g., the second cell is a primary cell) based on the second cell being the WTRU's new serving cell and the mobility to the second cell resulting in activation of a third cell of the plurality of mobility candidate cells as a secondary cell. The WTRU may determine the second measurement configuration to activate.

[0139] The WTRU may activate the determined one or more measurement configurations and CSI reporting configurations and transmit an indication to the network at 1010. For example, the WTRU may perform one or more measurements associated with the second measurement configuration and transmit at least one measurement report via the second cell based on the measurements associated with the second measurement configuration.

[0140] The processes and approaches described herein may be applied in any combination, may be applied to other wireless technologies, and may be used for other services.

[0141] The WTRU may refer to an identity of a physical device, or to an identity of a user, such as a subscription-related identity, eg, MSISDN, SIP URI, etc. The WTRU may refer to an application-based identity, such as a user name that may be used for each application.

[0142] The processes described above may be implemented in a computer program, software, and / or firmware incorporated into a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or 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, but not limited to, internal hard drives and removable disks), magneto-optical media, and / or optical media (such as CD-ROM disks and / or Digital Versatile Discs (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), comprising: A processor configured to: receiving configuration information indicating a plurality of mobility candidate cells and a plurality of measurement configurations; activating a first measurement configuration based at least in part on the first cell being a serving cell for the WTRU; receiving Layer 1 or Layer 2 (L1 / L2) control signaling indicating that the WTRU is to perform mobility to a second cell, the second cell being one of the plurality of mobility candidate cells; determining to activate a second measurement configuration of the plurality of measurement configurations when performing mobility to the second cell based on the second cell being a new serving cell for the WTRU and the mobility to the second cell results in activation of a third cell of the plurality of mobility candidate cells as a secondary cell, wherein the second cell is a primary cell; performing one or more measurements associated with the second measurement configuration; as well as A measurement report is transmitted via the second cell based on the measurement associated with the second measurement configuration.

2. The WTRU of claim 1 , wherein the L1 / L2 control signaling comprises a medium access control (MAC) control element (CE).

3. The WTRU of claim 1 , wherein the processor is further configured to receive the configuration information indicating the plurality of mobility candidate cells independently of the plurality of measurement configurations.

4. The WTRU of claim 1 , wherein the L1 / L2 control signaling indicates a new special cell (SpCell) and an activated secondary cell (SCell).

5. The WTRU of claim 1 , wherein the processor is further configured to receive the plurality of measurement configurations and associations with one or more SpCell and SCell combinations.

6. The WTRU according to claim 5, wherein the processor is configured to determine which of the multiple measurement configurations will be activated and which of the multiple measurement configurations will not be activated when performing mobility to the second cell based on one or more SpCell / SCell combinations.

7. The WTRU of claim 1 , wherein the configuration including the plurality of mobility candidate cells and the plurality of measurement configurations is received in a radio resource control (RRC) message.

8. The WTRU of claim 1 , wherein the one or more measurements associated with the second measurement configuration include channel state information (CSI) measurements.

9. The WTRU of claim 1 , wherein the processor is configured with one or more dependencies between a set of location-related configurations and a set of mobility functions.

10. The WTRU of claim 9, wherein activation of a location-dependent configuration activates an associated mobility function, and wherein activation of a mobility function activates an associated location-dependent configuration.

11. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving configuration information indicating a plurality of mobility candidate cells and a plurality of measurement configurations; activating a first measurement configuration based at least in part on the first cell being a serving cell for the WTRU; receiving Layer 1 or Layer 2 (L1 / L2) control signaling indicating that the WTRU is to perform mobility to a second cell, the second cell being one of the plurality of mobility candidate cells; determining to activate a second measurement configuration of the plurality of measurement configurations when performing mobility to the second cell based on the second cell being a new serving cell for the WTRU and the mobility to the second cell results in activation of a third cell of the plurality of mobility candidate cells as a secondary cell, wherein the second cell is a primary cell; performing one or more measurements associated with the second measurement configuration; as well as A measurement report is transmitted via the second cell based on the measurement associated with the second measurement configuration.

12. The method of claim 11, wherein the L1 / L2 control signaling comprises a medium access control (MAC) control element (CE).

13. The method according to claim 11, further comprising: The configuration information indicating the plurality of mobility candidate cells is received independently of the plurality of measurement configurations. The method according to claim 11 , wherein the L1 / L2 control signaling indicates a new special cell (SpCell) and an activated secondary cell (SCell).

15. The method according to claim 11, further comprising: The plurality of measurement configurations and associations with one or more SpCell and SCell combinations are received.

16. The method according to claim 15, further comprising: Which of the plurality of measurement configurations are to be activated and which of the plurality of measurement configurations are not to be activated when performing mobility to the second cell is determined based on the one or more SpCell / SCell combinations. 17 . The method of claim 11 , wherein the configuration comprising the plurality of mobility candidate cells and the plurality of measurement configurations is received in a radio resource control (RRC) message.

18. The method of claim 11, wherein the one or more measurements associated with the second measurement configuration comprise channel state information (CSI) measurements.

19. The method of claim 11, wherein the WTRU is configured with one or more dependencies between a set of location-related configurations and a set of mobility functions.

20. The method according to claim 19, wherein activation of one of the location-dependent configurations activates an associated mobility function, and wherein activation of a mobility function activates an associated location-dependent configuration.

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