Adaptive conditional layer-triggered mobility (LTM) and triggering of L1 measurement reporting

Abstract

A Wireless Transmit / Receive Unit (WTRU) may receive first configuration information. The first configuration information may include an indication of a first condition associated with one or more LTM cells. The WTRU may determine that the first condition is met. The WTRU may also receive second configuration information. The second configuration information may include an indication of a second condition associated with one or more candidate LTM cells. The WTRU may determine that the second condition is met. For example, based on determining that the first condition and / or the second condition is met, the WTRU may send an indication to select a cell from one or more candidate LTM cells.

Description

[0001] Cross-reference of related applications This application claims the benefit of U.S. Provisional Application No. 63 / 552,482, filed February 12, 2024, the entire contents of which are incorporated herein by reference. Background Technology

[0002] In RRC_CONNECTED, the Radio Transmit / Receive Unit (WTRU) can measure multiple beams (e.g., at least one) of the cell and / or the measurement results (e.g., power values) can be averaged to derive cell quality. The WTRU can be configured to consider a subset of the detected beams. Filtering can occur at different levels, such as two different levels. These two levels can include the physical layer to derive beam quality, and (e.g., then) the radio resource control (RRC) level to derive cell quality from multiple beams. For serving cells(one or more) and / or non-serving cells(one or more), the cell quality from beam measurements can be derived in the same manner. The measurement report can include the measurement results of X best beams, for example, if the WTRU is configured to do so by the gNB. Summary of the Invention

[0003] The systems and methods described herein may include one or more of Layer 2 (L2) triggered mobility (LTM), conditional handover (CHO), conditional LTM, and / or Layer 1 (L1) triggered measurement reports. Additionally or alternatively, the systems and methods described herein may be associated with fifth-generation (5G) new radio (NR) and / or mobility enhancements.

[0004] L1 and / or Layer 3 (L3) measurement interactions may exist, for example, for evaluating conditional LTM triggering conditions. Network-controlled conditional criterion modifications may exist. WTRU-autonomous conditional criterion modifications may exist. L1 event-triggered reporting conditions may exist, such as beam stability. L1-triggered beam stability reporting can be used for (e.g., explicit) LTM. WTRU-based TA measurement reporting triggering can be used for L1 reporting / conditional LTM. WTRU-based TA measurement reporting can be used for (e.g., conditional and / or explicit) LTM preparation.

[0005] The Wireless Transmit / Receive Unit (WTRU) can receive configuration information. This configuration information may include thresholds and / or indications for one or more candidate Layer Triggered Mobility (LTM) cells. The WTRU can measure the value of the first cell among the one or more candidate LTM cells. The WTRU can determine that this value is greater than or equal to the threshold. The WTRU can transmit a report based on this determination.

[0006] The threshold may include one or more of the following: System Information Block (SSB) value, Channel State Information (CSI) - Reference Signal (RS) value, Timing Advance (TA) value, and / or Beam Stability value. The WTRU may transmit this report in one or more of the Media Access Control (MAC) Control Element (CE) and / or Channel State Information (CSI) messages. The value may include a first value. The threshold may include a first threshold. Configuration information may include a second threshold. The WTRU may measure a second value of a first cell in one or more candidate LTM cells and / or determine that the second value is greater than or equal to a second threshold. The WTRU may transmit a report based on determining that the first value is greater than or equal to the threshold and / or determining that the second value is greater than or equal to the second threshold.

[0007] The WTRU may receive first configuration information. The first configuration information may include an indication of a first condition associated with one or more LTM cells. The WTRU may determine that the first condition is met. The WTRU may receive second configuration information. The second configuration information may include an indication of a second condition associated with one or more candidate LTM cells. The WTRU may determine that the second condition is met. For example, based on determining that the first condition and / or the second condition is met, the WTRU may send an indication to select a cell from one or more candidate LTM cells.

[0008] The first condition may include a Layer 1 condition. The WTRU may perform Layer 1 measurements associated with one or more candidate LTM cells. The WTRU may compare the Layer 1 measurements with the Layer 1 condition. The Layer 1 measurements may include a first Layer 1 measurement and / or the Layer 1 condition may include a first Layer 1 condition. The Layer 1 measurements may include, for example, one or more of the Reference Received Power (RSRP) and / or Received Signal Strength Indication (RSSI) associated with one or more cells and / or beams. The WTRU may perform a second Layer 1 measurement associated with one or more candidate LTM cells. The WTRU may compare the Layer 1 measurements with the second Layer 1 condition. The WTRU may determine whether the first condition is met based on the comparison of the first Layer 1 measurements with the first Layer 1 condition and / or based on the comparison of the second Layer 1 measurements with the second Layer 1 condition.

[0009] Layer 1 conditions may include thresholds associated with one or more of the following: SSB value, Channel State Information (CSI-RS) value, TA value, or beam stability value. Secondary conditions may include Layer 3 conditions. The WTRU may perform Layer 3 measurements associated with one or more candidate LTM cells. The WTRU may compare Layer 3 measurements with Layer 3 conditions. Layer 3 measurements may include, for example, filtering measurements associated with one or more cells or beams.

[0010] After receiving the second configuration information, the WTRU can determine that the first condition is met. The WTRU can send a message indicating that the first condition has been met. For example, after determining that the first condition is met, the WTRU can send an indication based on a time limit to select a cell from one or more candidate LTM cells. The WTRU can receive an indication to modify the first condition. For example, configuration information (e.g., first configuration information and / or second configuration information) may include an indication to modify the first condition. The WTRU can modify the first condition based on this indication. The WTRU can determine that the first condition is met based on the modification of the first condition. Attached Figure Description

[0011] Figure 1A This is a system diagram illustrating an example communication system in which one or more of the disclosed embodiments may be implemented.

[0012] Figure 1B The illustration shows that, according to the embodiment, it is possible to... Figure 1A The diagram shows a system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system.

[0013] Figure 1C The illustration shows that, according to the embodiment, it is possible to... Figure 1A The illustrated system diagram shows an example radio access network (RAN) and an example core network (CN) used in the communication system.

[0014] Figure 1D The illustration shows that, according to the embodiment, it is possible to... Figure 1A The illustrated system diagram shows another example RAN and another example CN used in the communication system.

[0015] Figure 2 This is an example of an advanced measurement model.

[0016] Figure 3 An example of LTM operation is shown.

[0017] Figure 4 An example of the LTM process is shown.

[0018] Figure 5 An example of beam thinning is shown.

[0019] Figure 6 An example of a conditional standard modification for network control based on a report of the first standard is shown.

[0020] Figure 7 An example of a WTRU autonomous conditional standard modification based on a report of the first standard is shown.

[0021] Figure 8An example of an L1-triggered beam stability report for explicit LTM is shown.

[0022] Figure 9 This is an example of a WTRU-based TA measurement report for LTM preparation. Detailed Implementation

[0023] Figure 1A This is a schematic diagram illustrating an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, and broadcasting to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Zero-Tail Unique Word DFT Spread Spectrum OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), and so on.

[0024] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, 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, any of WTRUs 102a, 102b, 102c, and 102d 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), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain scenarios), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, and so on. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs.

[0025] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, base stations 114a and 114b may be a basic transceiver station (BTS), Node-B, eNodeB, home Node B, home eNode B, gNB, NR NodeB, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are each depicted as a single element, it will be appreciated that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0026] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio 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 coverage of a specific geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In embodiments, 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.

[0027] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116. The air interface can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0028] More specifically, as noted above, communication system 100 can be a multiple access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base station 114a in RAN 104 / 113 and WTRUs 102a, 102b, 102c can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can establish air interfaces 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA can include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0029] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which can establish air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0030] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can establish air interface 116 using new radio (NR).

[0031] In the embodiments, base station 114a and WTRUs 102a, 102b, and 102c can implement various radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can, for example, use the dual connectivity (DC) principle to implement both LTE and NR radio access. Therefore, the air interface utilized by WTRUs 102a, 102b, and 102c can be characterized by various types of radio access technologies and / or transmissions sent to / from various types of base stations (e.g., eNBs and gNBs).

[0032] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., Global Microwave Access Interoperability (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced GSM Evolution Data Rate (EDGE), GSM EDGE (GERAN), and so on.

[0033] Figure 1ABase station 114b can be, for example, a wireless router, a home Node B, a home eNode B, or an access point, and can utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business premises, residence, vehicle, campus, industrial facility, air corridor (e.g., for drone use), road, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can have a direct connection to Internet 110. Therefore, it is not required that base station 114b access Internet 110 via CN 106 / 115.

[0034] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have varying Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although not explicitly stated... Figure 1A As shown, but will be understood, RAN 104 / 113 and / or CN106 / 115 can communicate directly or indirectly with other RANs that use the same RAT as RAN 104 / 113 or a different RAT. For example, in addition to connecting to RAN 104 / 113, which may be using NR radio technology, CN 106 / 115 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0035] CN 106 / 115 can also serve as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using 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. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 113 or a different RAT.

[0036] Some or all of the WTRUs 102a, 102b, 102c, and 102d in communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a, which may employ cellular-based radio technology, and with base station 114b, which may employ IEEE 802 radio technology.

[0037] Figure 1B The following diagram illustrates the system of example WTRU 102. Figure 1B As shown, among other things, WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138. It will be appreciated that WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0038] Processor 118 can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 can perform signal decoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 can be coupled to transceiver 120, and transceiver 120 can be coupled to transmitting / receiving element 122. Although... Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it will be understood that the processor 118 and transceiver 120 can be integrated together into an electronic package or chip.

[0039] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In another embodiment, transmitting / receiving element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF signals and optical signals. It will be appreciated that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0040] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. More specifically, WTRU 102 may employ MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via air interface 116.

[0041] Transceiver 120 can be configured to modulate signals to be transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As noted above, WTRU 102 can have multi-mode capability. Thus, for example, transceiver 120 can include multiple transceivers for enabling WTRU 102 to communicate via various RATs such as NR and IEEE 802.11.

[0042] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit) and can receive user input data from these devices. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access information from any type of suitable memory and store the data in 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, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 can access information from memory that is not physically located on WTRU 102 (such as on a server or home computer (not shown)) and store the data in that memory.

[0043] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 can be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cell units, fuel cell units, etc.

[0044] 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) about the current location of the WTRU 102. In addition to, or alternatively to, the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information using any suitable location determination method, while remaining consistent with the embodiments.

[0045] The processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or video), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral devices 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0046] WTRU 102 may include a full-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with a specific subframe of both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or via signal processing (e.g., a separate processor (not shown) or via processor 118). In embodiments, WTRU 102 may include a half-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with a specific subframe of either UL (e.g., for transmission) or downlink (e.g., for reception) may be concurrent and / or simultaneous.

[0047] Figure 1C This is a system diagram illustrating RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0048] RAN 104 may include eNode-Bs 160a, 160b, and 160c; however, it should be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, for example, eNode-B 160a may use multiple antennas to transmit and / or receive radio signals from WTRU 102a.

[0049] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0050] Figure 1C The CN 106 shown 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 described as part of CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0051] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0052] The SGW 164 can connect to each of the eNode Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can typically route and forward user data packets to / from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions, such as anchoring the user plane during handover between eNode Bs, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c.

[0053] SGW 164 can be connected to PGW 166, which can provide WTRU 102a, 102b, 102c with access to packet-switched networks such as Internet 110 to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0054] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRU 102a, 102b, 102c with access to circuit-switched networks such as PSTN 108 to facilitate communication between WTRU 102a, 102b, 102c and traditional landline communication equipment. For example, CN 106 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and PSTN 108. Furthermore, CN 106 can provide WTRU 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0055] Despite WTRU in Figures 1A-1D While described as a wireless terminal, it is conceivable that in some representative embodiments, such a terminal may use (e.g., temporarily or permanently) a wired communication interface with a communication network.

[0056] In a representative embodiment, the other network 112 may be a WLAN.

[0057] A WLAN in Infrastructure Basic Services Set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can access or interface to a distributed system (DS) or another type of wired / wireless network that carries traffic to and / or out of the BSS. Traffic originating outside the BSS and destined for a STA can arrive via the AP and be transmitted to the STA. Traffic originating from a STA and destined for a destination outside the BSS can be sent to the AP for transmission to the appropriate destination. For example, traffic between STAs within the BSS can be transmitted via the AP, where a source STA can send traffic to the AP, and the AP can transmit traffic to a destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be transmitted between a source STA and a destination STA (e.g., directly between them) using Direct Link Establishment (DLS). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as the "ad-hoc" communication mode in this document.

[0058] When using 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of a fixed width (e.g., a 20 MHz wide bandwidth) or dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) can be implemented, for example in an 802.11 system. For CSMA / CA, each STA, including the AP, can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, that particular STA can exit. A single STA (e.g., only one station) can transmit at any given time within a given BSS.

[0059] High-throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels.

[0060] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non-consecutive 80 MHz channels; this can be referred to as an 80+80 configuration. For the 80+80 configuration, after channel coding, the data can be divided into two streams by a segmented parser. Each stream can be processed individually using Inverse Fast Fourier Transform (IFFT) and time-domain processing. The streams can be mapped onto the two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operation of the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0061] 802.11af and 802.11ah support sub-1 GHz operating modes. Compared to those used in 802.11n and 802.11ac, the channel operating bandwidth and carrier in 802.11af and 802.11ah are reduced. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV Blank (TVWS) spectrum, and 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 metering-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, including limited capabilities such as supporting (e.g., only supporting) certain and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., to maintain very long battery life).

[0062] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be referred to as the primary channel. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by one STA operating in the BSS that supports the minimum bandwidth operating mode. In the example of 802.11ah, for STAs that support (e.g., only support) the 1MHz mode (e.g., MTC type devices), the primary channel can 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 Sense and / or Network Assignment Vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy, for example due to STAs (only supporting the 1 MHz operating mode) transmitting to the AP, the entire available band may be considered busy, even if most of the band remains idle and may be available.

[0063] In the United States, the available frequency band for 802.11ah is 902 MHz to 928 MHz. In South Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. Depending on the country code, the total available bandwidth for 802.11ah ranges from 6 MHz to 26 MHz.

[0064] Figure 1D This is a system diagram illustrating RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0065] RAN 113 may include gNBs 180a, 180b, and 180c; however, it should be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, for example, gNB 180a may use multiple antennas to transmit and / or receive radio signals from WTRU 102a. In embodiments, gNBs 180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers (not shown) to WTRU 102a. A subset of these component carriers can be on unlicensed spectrum, while the remaining component carriers can be on licensed spectrum. In embodiments, gNBs 180a, 180b, and 180c can implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0066] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable digitization. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing can differ for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and / or a continuously varying length of absolute time).

[0067] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can utilize one or more gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c, while also communicating / connecting with another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c, as well as one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-Bs 160a, 160b, and 160c can act as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0068] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing user plane data to User Plane Functions (UPF) 184a and 184b, and routing control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0069] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements 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 a CN operator.

[0070] AMF 182a and 182b can be connected to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF183a and 183b, managing registration areas, terminating NAS signaling, mobility management, etc. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the service type used by WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services relying on Ultra Reliable Low Latency (URLLC) access, services relying on Enhanced Massive Mobile Broadband (eMBB) access, and services for Machine Type Communication (MTC) access. AMF 162 can provide control plane functions for handover between RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro and / or non-3GPP access technologies such as WiFi.

[0071] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure traffic routing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0072] UPF 184a and 184b can be connected to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface. This interface provides WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0073] CN 115 can facilitate communication with other networks. For example, CN 115 may include, or can communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. Furthermore, CN 115 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c can connect to local data networks (DNs) 185a and 185b via UPFs 184a and 184b through their N3 interfaces and the N6 interface between UPFs 184a and 184b and DNs 185a and 185b.

[0074] Given Figures 1A-1D as well as Figures 1A-1D The functions described herein with respect to one or more of the following items can be performed by one or more emulation devices (not shown): WTRU 102a-102d, base station 114a-114b, eNode-B 160a-160c, MME 162, SGW 164, PGW 166, gNB 180a-180c, AMF 182a-ab, UPF 184a-184b, SMF 183a-183b, DN 185a-185b, and / or one or more other devices described herein. An emulation device can be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0075] Simulation devices can be designed to perform tests on one or more other devices in laboratory and / or carrier network environments. For example, one or more simulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. For testing purposes, simulation devices can be directly coupled to another device and / or can use over-the-air wireless communication to perform tests.

[0076] One or more emulation devices may perform one or more functions (including all functions) without being implemented / deployed as part of a wired and / or wireless communication network. For example, emulation devices may be used in test scenarios within test laboratories and / or non-deployed (e.g., test) wired and / or wireless communication networks to perform testing of one or more components. One or more emulation devices may be test rigs. Emulation devices may transmit and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas). The terms UE and WTRU are used interchangeably herein.

[0077] The Wireless Transmit / Receive Unit (WTRU) can receive configuration information. This configuration information may include thresholds and / or indications for one or more candidate Layer Triggered Mobility (LTM) cells. The WTRU can measure the value of the first cell among the one or more candidate LTM cells. The WTRU can determine that this value is greater than or equal to the threshold. The WTRU can transmit a report based on this determination.

[0078] The threshold may include one or more of the following: System Information Block (SSB) value, Channel State Information (CSI) - Reference Signal (RS) value, Timing Advance (TA) value, and / or Beam Stability value. The WTRU may transmit this report in one or more of the Media Access Control (MAC) Control Element (CE) and / or Channel State Information (CSI) messages. The value may include a first value. The threshold may include a first threshold. Configuration information may include a second threshold. The WTRU may measure a second value of a first cell in one or more candidate LTM cells and / or determine that the second value is greater than or equal to a second threshold. The WTRU may transmit a report based on determining that the first value is greater than or equal to the threshold and / or determining that the second value is greater than or equal to the second threshold.

[0079] The WTRU may receive first configuration information. The first configuration information may include an indication of a first condition associated with one or more LTM cells. The WTRU may determine that the first condition is met. The WTRU may receive second configuration information. The second configuration information may include an indication of a second condition associated with one or more candidate LTM cells. The WTRU may determine that the second condition is met. For example, based on determining that the first condition is met and / or based on determining that the second condition is met, the WTRU may send an indication to select a cell from one or more candidate LTM cells.

[0080] The first condition may include a Layer 1 condition. The WTRU may perform Layer 1 measurements associated with one or more candidate LTM cells. The WTRU may compare the Layer 1 measurements with the Layer 1 condition. The Layer 1 measurements may include a first Layer 1 measurement and / or the Layer 1 condition may include a first Layer 1 condition. The Layer 1 measurements may include, for example, one or more of the Reference Received Power (RSRP) and / or Received Signal Strength Indication (RSSI) associated with one or more cells and / or beams. The WTRU may perform a second Layer 1 measurement associated with one or more candidate LTM cells. The WTRU may compare the Layer 1 measurements with the second Layer 1 condition. The WTRU may determine whether the first condition is met based on the comparison of the first Layer 1 measurements with the first Layer 1 condition and / or based on the comparison of the second Layer 1 measurements with the second Layer 1 condition.

[0081] Layer 1 conditions may include thresholds associated with one or more of the following: SSB value, Channel State Information (CSI-RS) value, TA value, or beam stability value. Secondary conditions may include Layer 3 conditions. The WTRU may perform Layer 3 measurements associated with one or more candidate LTM cells. The WTRU may compare Layer 3 measurements with Layer 3 conditions. Layer 3 measurements may include, for example, filtering measurements associated with one or more cells or beams.

[0082] After receiving the second configuration information, the WTRU can determine that the first condition is met. The WTRU can send a message indicating that the first condition has been met. For example, after determining that the first condition is met, the WTRU can send an indication based on a time limit to select a cell from one or more candidate LTM cells. The WTRU can receive an indication to modify the first condition. For example, configuration information (e.g., first configuration information and / or second configuration information) may include an indication to modify the first condition. The WTRU can modify the first condition based on this indication. The WTRU can determine that the first condition is met based on the modification of the first condition.

[0083] Figure 2This is an example of an advanced measurement model 200. For example, in RRC_CONNECTED, the WTRU can measure one or more (e.g., multiple) beams of a cell. The WTRU can average the measurement results (e.g., power values) to derive cell quality, for example. The WTRU can be configured to consider a subset of the detected beams. Filtering can occur at different levels, for example, at two different levels. These two levels can include a physical layer to derive beam quality and / or (e.g., then) a Radio Resource Control (RRC) level to derive cell quality from multiple beams. For serving cells (one or more) and / or non-serving cells (one or more), the cell quality from the beam measurements can be derived in the same manner. The measurement report can contain the measurement results of X best beams, for example, if the WTRU is configured to do so by the gNB.

[0084] A network (e.g., a gNB) can transmit multiple beams. For example, a network can transmit K beams. At 202, the WTRU can filter the beams, for example, each beam. For example, Layer 1 filtering can be performed on each beam. Filtering can be WTRU implementation-specific. The RRC layer can be configured with parameters, such as for beam combining and / or selection, for Layer 3 filtering for cell quality, and / or for reporting criterion evaluation. At 204, the WTRU can perform beam combining and / or selection (e.g., using the filtered beams). At 206, the WTRU can perform Layer 3 filtering for cell quality. At 208, the WTRU can evaluate reporting criteria. The WTRU can (e.g., then) report. At 210, for example, after 202, the WTRU can perform Layer 3 (L3) beam filtering (e.g., for K beams). At 212, the WTRU can (e.g., then) perform beam selection for reporting. The WTRU can (e.g., then) report.

[0085] The systems and methods described herein may include one or more of Layer 2 (L2) triggered mobility (LTM), conditional handover (CHO), conditional LTM, and / or Layer 1 (L1) triggered measurement reporting. Additionally or alternatively, the systems and methods described herein may be associated with fifth-generation (5G) new radio (NR) and / or mobility enhancements.

[0086] L1 and / or Layer 3 (L3) measurement interactions may exist, for example, for evaluating conditional LTM triggering conditions. Network-controlled conditional criterion modifications may exist. WTRU-autonomous conditional criterion modifications may exist. L1 event-triggered reporting conditions may exist, such as beam stability. L1-triggered beam stability reporting can be used for (e.g., explicit) LTM. WTRU-based TA measurement reporting triggering can be used for L1 reporting / conditional LTM. WTRU-based TA measurement reporting can be used for (e.g., conditional and / or explicit) LTM preparation. As used herein, LTM may refer to layer-triggered mobility. This layer may be, for example, L2. This layer may be, for example, L1 / L2. For example, this layer may be L1.

[0087] Systems and methods may include inter-cell L1 / L2 (Layer 1 / Layer 2) triggered mobility. Inter-cell beam management can manage beams, such as in the case of carrier aggregation (CA). In some examples, cell change / addition is not supported. Systems and methods for L1 / L2-based inter-cell mobility for mobility latency reduction may exist. For example, the configuration and / or maintenance of multiple candidate cells may allow (e.g., rapid) application of candidate cell configurations (e.g., RAN2, RAN3). For example, dynamic handover mechanisms between candidate serving cells (e.g., including SpCell and / or SCell) in potentially applicable scenarios may be based on L1 / L2 signaling (e.g., RAN2, RAN1). L1 enhancements for inter-cell beam management may exist, such as including L1 measurements and / or reporting, and / or beam indications (e.g., RAN1, RAN2). Early RAN2 involvement may be utilized for inter-cell beam management, such as including further clarification of the interaction between RAN2 and L1 enhancements.

[0088] Pre-management can be scheduled (e.g., RAN1, RAN2). Centralized Unit-Distributed Unit (CU-DU) interface signaling can support L1 / L2 mobility, for example, in RAN3. FR2-specific enhancements are not excluded. L1 / L2-based inter-cell mobility can be applied to one or more of the following: standalone, NR-DC with changing serving cell within a CA and a CG, intra-DU and inter-DU within a CU (e.g., applicable to standalone and CA and / or where no new RAN interface is expected), intra-frequency and inter-frequency (e.g., both), FR1 and FR2 (e.g., both), when source and destination cells can be synchronized or unsynchronized; and / or may not include inter-CU.

[0089] L1 / L2-based mobility and / or inter-cell beam management can address scenarios within a distributed cell (DU) and / or frequency. In this case, the serving cell remains unchanged (e.g., it is not possible to change the serving cell using L1 / L2-based mobility). For example, in a frequency range 2 (FR2) deployment, carrier aggregation (CA) can be used to utilize available bandwidth (e.g., aggregating multiple component carriers (CCs) in one frequency band). These component carriers (CCs) can be transmitted using the same analog beam pairs (e.g., gNB beams and / or WTRU beams).

[0090] The WTRU can be configured with Transmission Configuration Indicator (TCI) states (e.g., a considerable number, such as 64) for receiving the PDCCH and / or Physical Downlink Shared Channel (PDSCH). Each TCI state may include an RS and / or a Synchronization Signal Block (SSB). The WTRU may reference the RS and / or SSB for beamforming. The SSB may be associated with a non-serving PCI. MAC signaling (e.g., TCI state indication for a WTRU-specific PDCCH Media Access Control (MAC) Control Element (CE)) can activate TCI states for the Control Resource Set (CORESET) / Physical Downlink Control Channel (PDCCH).

[0091] MAC CE can support receiving PDCCH from a non-serving cell, for example, by indicating the TCI state associated with the non-serving PCI. MAC signaling (e.g., TCI state activation / deactivation for WTRU-specific PDSCH) can activate (e.g., up to) a subset of eight TCI states, for example, for PDSCH reception. DCI can indicate one of the eight TCI states (e.g., which one). For example, a unified TCI state can be additionally or alternatively supported with different update mechanisms (e.g., DCI-based) and / or without multiple TRPs. A unified TCI state with multiple TRPs can be supported.

[0092] LTM can improve handover latency. For example, for a regular L3 handover and / or conditional handover, the WTRU may first send a measurement report using RRC signaling. In response to the measurement report (e.g., from the WTRU), the network may provide (e.g., further) measurement configuration and / or conditional handover configuration. The network may provide a configuration for the target cell (e.g., for handover), for example, after the WTRU reports that the cell meets the configured radio quality criteria using RRC signaling. For example, to reduce the handover failure rate due to delays in sending measurement reports and then receiving RRC reconfiguration, the network may (e.g., in advance) provide the target cell configuration and / or measurement criteria. The target cell configuration and / or measurement criteria can be used to determine when the WTRU should trigger CHO configuration. Some L3 methods may involve delays due to sending measurement reports and / or receiving target configurations, for example, in regular (e.g., unconditional) handovers.

[0093] LTM can allow for (e.g., rapid) application of configurations to candidate cells, such as dynamic handovers between SCells and handovers between PCells (e.g., switching roles between SCells and PCells) without performing RRC signaling. Inter-CU scenarios may involve the relocation of PDCP anchor points. Therefore, an RRC-based approach, at least supporting inter-CU handovers, may be desirable.

[0094] For example, in some L3 handover mechanisms, any currently active(one or more) SCells can be released before the WTRU moves and / or completes the handover to the target cell in the coverage area of ​​the new site. Additionally, or alternatively, currently active(one or more) SCells can be added back (e.g., only) after a successful handover, which may, for example, lead to throughput degradation during the handover. L1 / L2 can enable CA operations to be enabled immediately upon a change in serving cell.

[0095] Figure 3An example of LTM operation 300 is shown. Candidate cell groups can be configured by RRC and / or use L1 / L2 signaling to implement dynamic handover between PCells and SCells. L1 / L2 signaling can be used for SCell activation and / or deactivation, for example, for inter-CU handover. Cell candidates can include one or more of cell 1 (e.g., 3.5 GHz), cell 2 (e.g., 2.1 GHz), cell 3 (e.g., 26 GHz), and / or cell 4 (e.g., 26 GHz). WTRU 302 can move, for example, in a direction. For example, when WTRU 302 moves, handover between cells can occur. For example, RRC can (e.g., initially) configure cells 1-4 as candidates. RRC can activate PCell1 and / or SCell2. When WTRU 302 moves, handover between cell 2 and cell 3 can occur (e.g., dynamically). When WTRU 302 moves further (e.g., in direction), there may be a (e.g., dynamic) PCell handover to cell 1 and / or a (e.g., dynamic) SCell handover to cell 4.

[0096] The LTM procedure may include the gNB receiving one or more L1 measurement reports from the WTRU. The gNB can change the WTRU's serving cell via a cell handover command signaled via MACCE, for example, based on one or more measurement reports. The cell handover command may indicate an LTM candidate configuration, such as a configuration previously prepared by the gNB and provided to the WTRU via RRC signaling. The WTRU can (e.g., then) switch to the target configuration based on the cell handover command. The LTM procedure can be used to reduce mobility latency.

[0097] For example, when configured by the network, the TCI state of one or more cells different from the currently serving cell can be activated. For example, the TCI state of an LTM candidate cell can be activated before any LTM candidate cell becomes the serving cell. The WTRU can (e.g., therefore) perform DL synchronization with those cells, which can, for example, facilitate a faster cell handover to one of the LTM candidate cells when a handover is triggered.

[0098] For example, when configured by the network, a UL TA acquisition (e.g., early TA) procedure can be initiated for one or more cells (e.g., cells different from the currently serving cell). For example, if a cell has the same N as the currently serving cell... TA and / or N TAIf the value is 0, the early TA acquisition procedure can be omitted. The network can request the WTRU to perform early TA acquisition for candidate cells, for example, before cell handover. The early TA acquisition procedure can be triggered by a PDCCH command and / or implemented through WTRU-based TA measurements as configured by RRC. For example, when triggered by a PDCCH command, a gNB (e.g., the gNB to which the candidate cell belongs) can calculate the TA value and / or send the TA value to the gNB to which the serving cell belongs. For example, when an LTM cell handover is triggered, the serving cell can send the TA value in the LTM cell handover command MAC CE.

[0099] For example, when the TA acquisition process is triggered by a WTRU-based TA measurement configured by RRC, the WTRU can perform TA measurements on the candidate cell after the RRC configuration. The exact time at which the WTRU can perform TA measurements can depend on the WTRU implementation. For example, upon receiving a cell handover command, the WTRU can apply the measured TA value and / or perform LTM without RACH. The network can additionally or alternatively send the TA value in the LTM cell handover command MAC CE without performing early TA acquisition.

[0100] For example, depending on the availability of a valid TA value, the WTRU can perform (e.g., or) LTM without RACH or LTM based on RACH cell handover. For example, if a TA value is provided in the cell handover command, the WTRU can apply the TA value (e.g., as instructed by the network). For example, when WTRU-based TA measurement is configured but no TA value is provided in the cell handover command, the WTRU can apply the TA value (e.g., if available). For example, upon receiving a cell handover command, the WTRU can perform LTM without RACH cell handover. For example, if no valid TA value is available, the WTRU can perform LTM based on RACH cell handover.

[0101] The WTRU may follow PDCCH commands, which may include, for example, requests for a random access procedure to a candidate cell. The WTRU may follow PDCCH commands regardless of whether it is configured for WTRU-based TA measurements of a candidate cell. Additionally or alternatively, the WTRU may follow PDCCH commands for candidate cells for which it can derive TA values. Additionally or alternatively, the WTRU may use WTRU-based measurement configurations, if configured by the network, regardless of whether it has already performed a random access procedure to the candidate cell.

[0102] For example, for LTM without RACH, the WTRU can use (e.g., or) configuration grant and / or dynamic grant to access the target cell. Configuration grant can be provided in the LTM candidate configuration. The WTRU can choose the timing of the configuration grant associated with the beam indicated in the cell handover command. For example, when initiating an LTM cell handover to the target cell, the WTRU can begin monitoring the PDCCH on the target cell for dynamic scheduling. For example, the WTRU may not trigger a random access procedure until the LTM without RACH procedure is complete. For example, if the WTRU does not have a valid PUCCH resource for triggering the SR, the WTRU may not trigger a random access procedure.

[0103] For example, security keys can be maintained during LTM cell handover. Subsequent LTMs can be supported. LTMs can support mobility within a gNB-DU and / or between gNB-DUs within a gNB-CU (e.g., both). LTMs can support intra-frequency and / or inter-frequency mobility (e.g., both), including mobility to inter-frequency cells that are not the currently serving cell. Licensed spectrum can support LTMs.

[0104] It can support PCell changes in non-CA and / or non-DC scenarios. It can support PCell and / or (one or more) SCell changes in CA scenarios. It can support PCell and (one or more) MCG SCell changes that do not involve the MN, as well as PSCell and (one or more) SCG SCell changes within the SN, such as in dual-connectivity scenarios. It may not support LTM where both PCell and PSCell change simultaneously. The WTRU can execute any L3 handover command sent by the network, such as when the WTRU has already stored LTM candidate configurations.

[0105] Figure 4An example of LTM procedure 400 is shown. WTRU 402 may be in RRC_CONNECTED mode. At 406, WTRU may send a MeasurementReport message to gNB 404. gNB 404 may determine LTM configuration and / or initiate LTM candidate preparation. At 408, gNB 404 may transmit an RRCReconfiguration message to WTRU 402, including, for example, the LTM candidate configuration. WTRU 404 may store the LTM candidate configuration. Additionally or alternatively, at 410, WTRU 402 may transmit an RRCReconfigurationComplete message to gNB 404. At 412, for example, before receiving a cell handover command, WTRU 402 may perform DL synchronization with one or more candidate cells. At 414, for example, before receiving a cell handover command, WTRU 402 may perform UL synchronization with one or more candidate cells.

[0106] For example, when WTRU-based TA measurement is configured, WTRU 402 can acquire TA values ​​of one or more candidate cells through measurement. WTRU 402 can perform early TA acquisition of one or more candidate cells based on network requests, such as before receiving a cell handover command. WTRU 402 can send a preamble to the indicated candidate cell, for example, after a CFRA triggered by a PDCCH command from the source cell. For example, to minimize data interruption to the source cell due to CFRA toward one or more candidate cells, WTRU 402 may not receive a random access response from the network for the purpose of acquiring TA values, and / or the TA values ​​of the candidate cells may be indicated in the cell handover command. WTRU 402 may not maintain a TA timer for the candidate cells and / or may rely on the network implementation, for example, to guarantee TA validity.

[0107] WTRU 402 can perform L1 measurements on one or more configured candidate cells. At 416, WTRU 402 can transmit an L1 measurement report to gNB 404. gNB 404 can determine to perform a cell handover to the target cell. At 418, gNB 404 can transmit a cell handover command, for example, in the MAC CE. For example, gNB 404 can include a candidate configuration index of the target cell in the cell handover command. WTRU 402 can detach from the source cell, hand over to the target cell, and / or apply the configuration indicated by the candidate configuration index. For example, if WTRU 402 does not have a valid TA for the target cell, WTRU 402 can perform a random access procedure with the target cell. At 422, WTRU 402 can complete LTM procedure 400.

[0108] For example, the WTRU can complete the LTM cell handover process by sending an RRCReconfigurationComplete message to the target cell. For example, if WTRU 402 has already performed the RA procedure (e.g., at 420), the WTRU can determine that the LTM cell handover has been successfully completed when the random access procedure completes successfully. For example, for LTM without RACH, WTRU 402 can determine that the LTM cell handover has been successfully completed when the WTRU determines that the network has successfully received the first UL data. In some examples, steps 412, 414, 416, 418, 420, and / or 420 can be performed multiple times, for example, for subsequent LTMs using (e.g., at 408) the provided LTM candidate configuration(s). For example, as... Figure 4 The procedures described in the document via the air interface (e.g., 400) can be applied to LTM within a gNB-DU and / or LTM between gNB-DUs (e.g., both). In some examples, the LTM procedure can be performed via the F1-C interface.

[0109] Systems and methods may include RACH-free LTM. The WTRU may perform early timing advance (TA) acquisition with one or more candidate cells, for example, before receiving a cell handover command. The WTRU may perform early TA acquisition with one or more candidate cells via contention-free random access (CFRA), for example, triggered by a PDCCH command from the source cell. The WTRU may (e.g., then) send a preamble to the candidate cells. Information identifying the allocated CFRA resources may be indicated in the PDCCH command, for example, to enable shared preamble resources among multiple WTRUs in an RRC configuration. The source gNB may (e.g., dynamically) indicate which WTRU uses the resource at any given time.

[0110] For example, the WTRU may not receive RAR (e.g., not at all) to minimize data interruption in the source cell, such as due to CFRA of one or more candidate cells. For example, if no preamble is received, the source cell can trigger a preamble retransmission / power ramp using another PDCCH command. For example, if the TA value of the candidate cell is indicated in the cell handover command, the WTRU can perform a RACH-free handover. Additionally or alternatively, the WTRU may support and / or be configured with WTRU-based TA measurements, such that the WTRU can obtain the TA values ​​of one or more candidate cells by measurement. For example, if the cell handover command does not include TA values ​​and / or the WTRU has already obtained TA measurements, the WTRU can perform a RACH-free handover. For example, if configured by RRC, the WTRU can perform a RACH-free handover.

[0111] L1 / L2 triggered mobility (LTM) procedures can improve mobility latency, for example, through one or more of the following: pre-configuration of multiple target cells before handover, early DL / UL synchronization of target cells, L1 measurement reporting, and / or MAC CE to indicate cell handover. Measurement-related enhancements (e.g., RAN2, RAN1) may exist to support LTM. Measurement-related enhancements may be applicable to intra-CU primary cell group (MCG) / secondary cell group (SCG) LTM and / or inter-CU MCG / SCG LTM. Components (e.g., necessary components) for supporting event-triggered L1 measurement reporting (e.g., RAN2, RAN1) may be specified. RAN1 and / or RAN2 may (e.g., independently) make progress on their respective MIMO and / or mobility enhancement event-triggered measurement objectives. This document discloses support for Channel State Information (CSI)-Reference Signal (RS) measurements for LTM procedures and / or support for enabling CSI-RS-based beam management. This paper discloses additional physical layer operations on candidate cells prior to LTM (e.g., RAN1).

[0112] Support for conditional LTMs (e.g., RAN2, RAN3, RAN1) can be specified. Conditions used to trigger LTMs, as evaluated by the WTRU, can be specified. This document may include systems and methods for supporting conditional LTMs that include subsequent LTMs. In some examples, in-CU LTMs can be prioritized.

[0113] LTM can allow for improved latency and / or reduced outages. L3 Conditional Handover (CHO) can achieve (e.g., more) robust mobility, for example, by reducing RLF and / or HOF. However, L3 CHO can use L3 filtering and / or triggering time to determine the appropriateness of the target, for example, to avoid failures at the target and / or reduce ping-pong effects. For example, using L1 measurements instead of L3 measurements can achieve latency improvements.

[0114] LTM can use a CSI reporting framework, which can support periodic CSI reporting (e.g., transmitting CSI reports at fixed pre-configured intervals) and / or non-periodic CSI reporting (e.g., in response to explicit network requests). CSI reporting can support scheduling and / or beam management in the serving cell, which can be achieved by leveraging frequent reporting. However, mobility events may be less frequent and / or the use of CSI reporting may imply significant signaling overhead. Therefore, event-triggered reporting, similar to L3 measurements, can be used to support mobility.

[0115] The systems and methods presented in this paper address aspects of measurement improvement in LTM. For example, the systems and methods address L1 reporting and / or conditional LTM triggered by triggering events. The systems and methods utilize shorter trigger times and / or unfiltered measurements to address L1 events. The systems and methods can address providing robustness and / or avoiding unwanted ping-pong effects without compromising latency. The systems and methods can address one or more of the following: improved stability, reduced ping-pong effects due to reduced or lack of measurement filtering, improved efficiency of resource reservations in the network (NW) (e.g., for CG without RACH, CSI reporting resources on PUCCH), and / or (e.g., simultaneously) maintaining the better latency and / or interruptions provided by LTM.

[0116] Adaptive conditional LTM can exist. Combinations and / or interactions between L3 filtered measurements and L1 unfiltered measurements can be used to determine CHO triggering. Interactions between L1 and L3 measurements can be used to dynamically update C-LTM parameters. The output / results of an evaluation of one measurement type can be used to adjust parameters used to evaluate other measurement types. WTRUs can be configured with multiple measurement conditions, which can be satisfied before C-LTM can be triggered. For example, if at least one condition is satisfied, an L1 report can be triggered (e.g., to notify the NW that C-LTM is possible, allowing the network to prepare resources on the target, such as configuring authorization and / or instructing / updating resources to the WTRU). The network (NW) can indicate the value of a second condition (e.g., time, relative threshold). For example, LTM can be triggered when one or more of the conditions (e.g., all conditions) (e.g., including additional conditions) are satisfied.

[0117] The WTRU can receive configurations of LTM candidate cells, such as conditional LTM configurations. (e.g., conditional LTM) Configurations may include, for example, L1 conditions based on L1 measurements and / or associated L3 conditions based on, for example, L3 filtered measurements. L1 measurement conditions may be based on one or more of the following: RSRP thresholds (e.g., SSB and / or CSI-RS measurements), acquisition / availability of TA measurements based on the WTRU, one or more L1 filtered beam measurements, one or more beam stability measurements (e.g., the number of beam failure indications (BFI) at the target location within a time window that is better than the source), and / or counters and sliding windows (e.g., the number of times a beam exceeds a threshold within a specific time period). L3 conditions may reuse existing L3 events. Additionally or alternatively, L3 conditions may use one or more filtered beam measurements derived from one or more beam measurements and / or one or more cell quality measurements, and / or set a threshold relative to the highest beam measurement (e.g., if the L3 filtered measurement is higher than a threshold of X dB from a beam measurement that satisfies the L1 conditions).

[0118] The WTRU can perform (e.g., measurement) and / or evaluate L1 and / or L3 measurements on a configured target. For example, an L1 report can be triggered when a first condition is met, such as using one or more of MAC CE, CSI report, SR, and / or another L1 reporting mechanism. For example, the L1 beam may exceed a threshold X times (e.g., SSB and / or CSI-RS measurements). The WTRU may have acquired, for example, TA, beam RSRP, and / or beam stability using WTRU-based measurements above a threshold. The WTRU can perform a beam stability comparison between the source and the target. Additionally or alternatively, L3 criteria (e.g., a lower threshold) can be met and (e.g., then) parameters can be set and / or L1 beam triggering evaluated.

[0119] The WTRU can receive instructions for dynamically modifying C-LTM parameters, such as using MAC CE. The WTRU can receive validity period, updated thresholds, CG resource indication, counter values, window size, target beam, and / or beam stability targets. Additionally or alternatively, the WTRU can autonomously adjust the C-LTM evaluation. For example, the WTRU can be configured to set thresholds for L3 criteria relatively and / or scaled based on metrics obtained by performing L1 evaluation. For instance, if the WTRU detects a higher value for the beam failure indication on the target at a certain time (e.g., to ensure cell measurement stability), the threshold for L3 conditions can be increased.

[0120] For example, an LTM can be triggered when a first condition and / or a second condition are met. For instance, a filtered measurement might exceed a relative threshold and might satisfy the L1 condition. An LTM can be triggered within a certain timeframe following the fulfillment of the first condition (e.g., and the sending of a report). For example, if the condition is not met within a specific timeframe (e.g., the CG validity period), the WTRU can trigger a second report to the source (e.g., instead of triggering LTM). The WTRU can send an indication to the target. The WTRU can include trigger details in the indication, for example. Trigger details can include one or more of the following: a relative threshold setting, the timing of the trigger occurrence, a counter (e.g., a BFI count), and / or a measurement (e.g., the RSRP when acquiring a TA).

[0121] LTM can be executed. In this document, executing LTM and / or executing the LTM procedure can refer to executing, for example... Figure 4 Any of the steps described herein. Early synchronization of one or more candidate cells may exist in the DL and / or UL. L1 measurements and reporting of one or more candidate cells may be performed. Additionally or alternatively, handover between candidate cells may be performed (e.g., performing a handover). Performing LTM as described herein may refer to the movement and / or handover of the WTRU between multiple candidate cells during this process.

[0122] One or more candidate cell sets may exist. A candidate cell set may include a group of more than one RRC configuration, such as a handover configuration corresponding to one or more candidate SpCells and / or SCells. RRC configurations may be modeled and / or received as one or more complete RRC reconfiguration messages, one or more cell group configurations, and / or one or more cell configurations. Candidate cell configurations (e.g., each) may include a candidate configuration identifier, and / or candidate cell groups (e.g., each in a candidate cell group) may include a candidate cell group identifier. For example, if a grouping is performed at the RRC, a handover between different candidate cell sets may include updating the serving cell index and / or the candidate configuration index. The serving cell index and / or candidate configuration index may be used in L1 and / or MAC signaling, for example, to refer to a specific index. For example, a MAC CE that triggers a reconfiguration may include a candidate configuration index to inform the WTRU which cell to perform a reconfiguration on.

[0123] One or more candidate cell groups can be configured as a single list and / or group of candidate cell configurations at the RRC. For example, grouping may occur during the early synchronization and / or LTM execution phase, rather than the configuration phase. For instance, a candidate cell set may be considered a single group within the RRC configuration list and / or groups. Additionally or alternatively, the cells selected for performing early synchronization, L1 measurement, and / or LTM execution may depend on further grouping into multiple subsets of the entire candidate cell list. In some examples, grouping may not be modeled using candidate configuration identifiers at the RRC. Grouping may be performed as part of the early synchronization and / or LTM execution process.

[0124] The references to LTM candidate configurations in this document can be applied to any type of pre-configured cell information. For example, a WTRU can be configured with one or more conditional reconfigurations. Example conditional reconfigurations may include one or more of conditional handover (CHO), conditional PSCell addition (CPA), and / or conditional PSCell change (CPC), which can be effective before and / or after a cell change, and / or in certain cells.

[0125] L1 measurements may exist. L1 measurements as described herein may include measurements of one or more of RSRP and / or RSSI, for example, performed by the WTRU on one or more of cells, beams, cell sets, and / or beam sets. L1 measurements may be similar to L3 measurements reported in the RRM, for example, differences may exist in one or more of filtering, reference signals for measurements, and / or reporting mechanisms.

[0126] One or more L1 measurements can be applied to RRM reports. Measurements in this document may refer to L1 measurements relative to LTM. The solutions in this document can be applied additionally or alternatively to RRM / L3 measurements. The solutions in this document can be applied additionally or alternatively to one or more other measurements, such as speed, position, height, and / or flow rate.

[0127] LTM cell handover can be applied to any type of handover (HO) execution. In this document, LTM cell handover can refer to L1 / L2 triggered mobility, for example, whereby a pre-configured RRC configuration is applied when the WTRU receives an indication using MAC CE and / or when a certain condition is met at the WTRU. The solutions described herein can be additionally or alternatively applied to one or more of the following: RRC reconfiguration, conditional RRC reconfiguration, and / or any other type of mobility procedure.

[0128] The solutions described in this paper can provide improved mobility robustness, for example, by ensuring stable measurements of mobility candidates / targets (e.g., improved radio link failure (RLF) / handover failure (HOF) rates). LTM can provide improved outages and / or latency on L3 mobility, for example, by enabling faster assessment of target suitability and / or stability. Compared to LTM, the systems and methods can reduce uplink resource overhead, for example, by enabling reduced L1 reporting in the absence of event-triggered L1 reporting and / or conditional LTM to support mobility. In some examples, network resource efficiency can be improved, for example, because resources may not be reserved on all potential candidate cells / beams until the WTRU indicates that conditional mobility triggering is possible.

[0129] LTM candidate configurations can exist. A gNB (e.g., a CU for a CU / DU split architecture) can use RRC signaling to configure (e.g., potential) LTM candidates. The RRC can reside in the CU. For example, during the LTM preparation phase (e.g., as... Figure 4 During this period (as shown), the WTRU can use RRC reconfiguration messages to receive LTM candidate configurations. The WTRU can store LTM candidate configurations for later application, such as when receiving an indication to perform a cell handover using L1 / L2 signaling (e.g., MAC CE). Figure 4 (during the LTM execution phase).

[0130] The configuration of potential LTM candidates may include one or more candidate sets. The first set may be applicable to the first path (e.g., the WTRU turns left and takes the first road), and / or the second set may be applicable to the second path (e.g., the WTRU turns right and takes the second road).

[0131] Candidate set information can be broadcast in system information. Additionally or alternatively, the WTRU may enable pre-configuration of broadcast configurations, such as upon receiving an indication in dedicated signaling (e.g., RRC reconfiguration). This indication may specify broadcasting one or more configurations (e.g., using indexes and / or identifiers).

[0132] The configuration may include all or a subset of candidate cells in a specific region (e.g., potential cells, such as all cells belonging to the CU currently connected to the WTRU and / or cells within a specific geographic region). Cells may not yet have been detected and / or measured by the WTRU, but may be configured in advance, for example. For instance, after the initial configuration of the LTM candidate configuration, the WTRU may receive updates to the configuration to modify, add, remove, and / or replace any part of (one or more) the LTM candidate configuration.

[0133] WTRU can receive instructions to enable or disable one or more LTM configurations. For example, if it is predicted that using L3 will better handle WTRU mobility (e.g., RRC measurement reporting, RRC reconfiguration, conditional reconfiguration), then (e.g., then) LTM can be disabled. For example, if it is predicted that LTM will be more suitable for WTRU mobility, then (e.g., then) LTM can be enabled (e.g., previously configured and disabled LTM configurations can be re-enabled).

[0134] Configuration can be based on a prediction model, such as one within the network (e.g., gNB) and / or a prediction model determined by the network. For example, predictions can be based on the most probable path(s) of the WTRU determined by it (e.g., a network (NW) prediction model).

[0135] Candidate cell configuration may contain all or part of the information necessary to complete reconfiguration (e.g., handover) to the candidate cell. Example information may include one or more of the following: channel configuration (e.g., PRACH, DPCCH, and / or DPSCH), CORESET, BWP, security parameters, L2 parameters (e.g., MAC, RLC, PDCP), and / or radio bearer configuration, etc.

[0136] LTM execution triggers may exist. In this document, an LTM execution trigger may refer to the conditions used to implement LTM (e.g., a conditional handover trigger or a measurement reporting trigger). The conditions used to execute LTM may be configured by the network and / or indicated to the WTRU. Additionally or alternatively, the conditions used to execute LTM may be estimated and / or determined by the WTRU.

[0137] Triggers can be time-based, such as absolute or relative time measurements at the WTRU, SFN, and / or subframe number. Triggers can be based on radio quality measurements and / or predicted radio quality (e.g., RSRP (beam or cell), RSRQ (beam or cell), cri-RI-PMI-CQI, cri-RI-i1, cri-RI-i1-CQI, cri-RI-CQI, cri-RSRP, ssb-Index-RSRP, and / or cri-RI-LI-PMI-CQI) of the WTRU. Triggers can be based on the location of the WTRU, such as an area (e.g., defined by a reference point and radius). Triggers can be based on coordinate ranges and / or distance thresholds from a reference location.

[0138] Triggers can be based on (e.g., any) L3 measurement events. For example, L3 measurement events can include one or more of the following: event A1 (e.g., service becomes better than a threshold), event A2 (e.g., service becomes worse than a threshold), event A3 (e.g., neighbors become better than SpCell offset), event A4 (e.g., neighbors become better than a threshold), event A5 (e.g., SpCell becomes worse than threshold 1 and neighbors become better than threshold 2), event A6 (e.g., neighbors become better than SCell offset), event B1 (e.g., inter-RAT neighbors become better than a threshold), and / or event B2 (e.g., PCell becomes worse than threshold 1 and inter-RAT neighbors become better than threshold 2).

[0139] Triggers can be based on (e.g., any) L1 measurement events and / or conditions (e.g., any event defined to utilize L1 beam measurements to assess whether a criterion or condition is met). Triggers can be based on (e.g., any) predicted events (e.g., using any measurements herein), explicit indications from the network (e.g., a WTRU can enable CSI reporting based on an explicit indication received from the network (e.g., a MAC CE), and / or (e.g., then) perform an LTM cell handover upon receiving a second MAC CE from the network). Triggers can be based on measured, predicted, and / or estimated throughput. Triggers can be based on measured, predicted, and / or estimated error rates; measured, predicted, and / or estimated buffer states; measured, predicted, and / or estimated quality of service (QoS) parameters; evaluation metrics (e.g., trigger time, hysteresis, offset (e.g., radio quality measurement offset), and / or measurement filter configuration). Triggers herein can be based on a combination of the disclosed triggers (e.g., bases).

[0140] Triggers may include one or more conditions under which the WTRU is configured to perform any action related to LTM. For example, the WTRU may perform one or more of the following: early TA acquisition, disabling CSI reporting, enabling and / or updating CSI reporting configuration, performing LTM cell handover, monitoring the PDCCH on the target cell, performing beam failure recovery (BFR) and / or radio link monitoring (RLM) on the target cell, and / or activating and / or deactivating (e.g., certain) SCells.

[0141] One or more conditions may include early TA acquisition. The WTRU may trigger a RACH to the target LTM cell. The WTRU may receive the TA value in the Random Access Response (RAR). The RAR may be transmitted from the target cell and / or via the source cell. The WTRU may receive the TA value, for example, in the MAC CE, to trigger a cell handover. For example, if no RAR / MAC CE is received, the WTRU may perform a power ramp and / or preamble retransmission on the target. The WTRU may acquire the TA value of a candidate LTM cell through measurement and / or triggering upon completion. The WTRU may support and / or be configured with WTRU-based TA measurement. For example, the WTRU may acquire the TA values ​​of one or more candidate cells through measurement.

[0142] One or more conditions may include disabling CSI reporting. For example, to reduce reporting overhead in the uplink, the WTRU may be allowed and / or configured to disable CSI reporting. In some examples, CSI reporting may be reduced rather than disabled. For example, the number of cells or beams reported may be reduced, and / or the reporting frequency may be reduced. For example, the WTRU may resume CSI reporting when the conditions are no longer met.

[0143] One or more conditions may include enabling and / or updating CSI reporting configuration. The WTRU may be configured to, for example, perform and / or report CSI measurements on one and / or a subset of LTM candidate cells during a window. One or more conditions may include performing an LTM cell handover. Conditions and / or criteria may exist under which the WTRU is configured (e.g., permitted) to trigger an LTM cell handover.

[0144] One or more conditions may include monitoring the PDCCH on the target cell. The WTRU may be configured to monitor the DCI scheduling PDSCH on the target cell and / or indicate one or more actions on the target cell, such as initiating a cell handover procedure. One or more conditions may include performing BFR and / or RLM on the target cell. The WTRU may be configured, for example, to monitor beam failure detection (BFD) resources on the target cell during a window, and / or perform RLM (radio link monitoring) on ​​the target cell. One or more conditions may include activating and / or deactivating (e.g., certain) SCells. The WTRU may be configured with one or more specific SCells that should be active or inactive, for example, during a window.

[0145] A RACH-free CHO and / or early TA acquisition may exist. For example, the WTRU may perform an early TA acquisition procedure on one or more candidate cells before receiving a cell handover command and / or before triggering a conditional reconfiguration. The WTRU may perform an early TA acquisition procedure on one or more candidate cells before receiving a cell handover command and / or before triggering a condition, for example, to enable RACH-free conditional handover. Additionally or alternatively, after reconfiguration is triggered, the WTRU may not need to send a random access preamble and / or perform a random access procedure on the target cell. For example, the WTRU may use the reconfiguration provided by the TA (e.g., already) to perform PDCCH reception and / or uplink transmission.

[0146] Early TA acquisition can be performed using contention-free random access (CFRA), for example, triggered by a PDCCH command from the source cell. The WTRU can (e.g., then) send a preamble to the candidate cell. Information identifying the allocated CFRA resource can be indicated by a PDCCH command, for example, to enable shared preamble resources among multiple WTRUs in an RRC configuration. The source gNB can (e.g., dynamically) indicate which WTRU uses and / or can use the resource at any given time. Upon receiving a MAC CE instructing RACH transmission on the target cell, the network (e.g., gNB) can indicate which WTRU uses and / or can use the resource at any given time. In some examples, the network (e.g., gNB) can indicate which WTRU uses and / or can use the resource at any given time, which can be performed by using a contention-based random access (CBRA) preamble for transmission.

[0147] For example, to minimize data interruption in the source cell due to CFRA towards one or more candidate cells, the WTRU may not receive the RAR (e.g., not receive it at all). For example, if the preamble is not received, the source cell can use another PDCCH command to trigger preamble retransmission and / or power ramp. TA can be provided from the target cell to the source cell (e.g., in this case). Additionally or alternatively, the TA can be provided to the WTRU in MAC CE-triggered cell handover and / or enabled conditional LTM for one or more target cells. In some examples, the WTRU can receive the TA value from the target cell in the RAR. The WTRU can also receive the TA value from the source cell in the RAR. For example, if the WTRU does not receive the RAR in response to the transmission of the preamble (e.g., within a specified time), the WTRU can use higher transmission power to retransmit the preamble.

[0148] The WTRU can store received TA values, for example, for later use when a reconfiguration trigger occurs. The WTRU can store TA values ​​for a limited time period (e.g., a validity timer), and / or can trigger and / or be triggered to perform a new TA acquisition procedure when the time expires. In some examples, the WTRU can receive and / or store multiple TA values ​​associated with more than one cell. In some examples, the WTRU can obtain the TA value of a target cell through measurement. For example, if the WTRU has stored a valid TA value for a candidate cell when a cell handover to a candidate cell is triggered (e.g., triggered by the NW using an explicit cell handover command, or triggered by the WTRU when triggering conditions are met), then (e.g., then) the WTRU can perform a RACH-free handover. For example, if the WTRU determines that the measured radio quality of the target cell is above a threshold, it can perform LTM (e.g., applying a pre-configured RRC configuration to a new SpCell). The WTRU can support and / or be configured with WTRU-based TA measurements. The WTRU can obtain the TA values ​​of one or more candidate cells through measurement. For example, if the cell handover command does not include the TA value and / or the WTRU has already acquired the TA measurement, the WTRU can perform a RACH-free handover (e.g., if it has been configured to do so by the RRC).

[0149] TA validity may exist. The WTRU may determine the validity of received and / or stored TA based on, for example, one or more of the following: a validity timer pre-configured for use with the TA value, a validity timer received with the TA value, conditions regarding DL cell timing for the source cell and / or candidate cells for which it received / stored the TA, conditions regarding DL cell timing for candidate cells, conditions regarding WTRU mobility, conditions regarding WTRU location, and / or conditions based on the availability of WTRU-based TA measurements and / or cell quality or beam quality measurements exceeding a threshold.

[0150] The WTRU can determine whether a received and / or stored TA is valid, for example, based on conditions relating to the DL cell timing of the source cell and / or the DL cell timing of the candidate cell for which it receives / stores the TA. For example, the WTRU can determine (e.g., consider) that the TA is valid when the difference between the DL cell timings of the source cell and the candidate cell is less than a configured threshold. For example, the WTRU can determine (e.g., consider) that the TA is valid when the difference between the DL cell timings of the source cell and the candidate cell is within a configured range.

[0151] The WTRU can determine the validity of a received and / or stored TA based on the candidate cell's DL cell timing. If the difference between the target cell's DL cell timing and the current DL cell timing of the same target cell at the time of TA reception does not exceed a certain configured value / range, the WTRU can determine (e.g., consider) the TA to be valid. The WTRU can also determine the validity of a received and / or stored TA based on conditions regarding its mobility. If the WTRU is stationary (e.g., not moving) and / or moving below a certain configured speed threshold, the WTRU can determine (e.g., consider) the TA to be valid. Finally, the WTRU can determine the validity of a received and / or stored TA based on conditions regarding its location. For example, after TA acquisition, if the WTRU has determined that it has not changed its location beyond a certain configured threshold (e.g., x meters), the WTRU can determine (e.g., consider) the TA to be valid.

[0152] Figure 5 An example of beam refinement 500 is shown. Beam refinement can be, for example, in an NR. The WTRU can measure SSBs before and / or during initial access. For example, the WTRU can perform measurements on SSB1, SSB2, and / or SSB3. The WTRU can indicate the SSB to the gNB, for example, by selecting a random access resource corresponding to the best-measured SSB. Once the WTRU is in RRC_CONNECTED, the beam can be refined (e.g., further) by configuring the WTRU to measure the CSI-RS set and report the measurement results (e.g., best CSI-RS index / CRI index or indicated RSRP). The gNB can use a wider beam to transmit SSB resources, and / or can use a narrower beam to transmit multiple CSI-RS resources. The beam can be refined (e.g., firstly) by using a wider SSB beam and / or (e.g., then) (e.g., afterwards) by selecting one of multiple narrower CSI-RS beams.

[0153] Beam refinement of the target cell may occur before and / or during the HO (Hospital Access). The WTRU may perform beam refinement of the target cell before and / or during handover, and / or before the WTRU accesses the target cell. For example, the WTRU first performs measurements of the SSB (Security Service Bus) resources, and then selects a subset of CSI-RS resources for measurement based on the SSB measurements (e.g., the optimal SSB based on the measurements). The WTRU may (e.g., then) perform measurements on the selected subset of CSI-RS resources and / or determine the optimal CSI-RS resources. For example, the selected optimal CSI-RS resources may be indicated before (e.g., to the source cell) the handover occurs and / or at the initial access (e.g., to the target cell), rather than only after beam refinement is performed after the connection to the target cell is completed.

[0154] The WTRU can report CSI-RS measurements. For example, the WTRU can report CSI-RS6, CSI-RS7, CSI-RS8, CSI-RS9, and / or CSI-RS10. The WTRU can, for example, use CSI reports on the PUCCH to report measurement results of a subset of CSI-RS resources to the source cell. Alternatively or additionally, reports can be transmitted using MAC CE and / or RRC measurement reports and / or any other type of uplink signaling. Reports can contain one or more of the following: RSRP (e.g., beam and / or cell), RSRQ (e.g., beam and / or cell), cri-RI-PMI-CQI, cri-RI-I, cri-RI-i1-CQI, cri-RI-CQI, cri-RSRP, ssb-Index-RSRP, and / or cri-RI-LI-PMI-CQI.

[0155] CSI-RS measurements can be enabled. The WTRU can determine the subset of CSI-RS to be measured, for example, based on triggers. For instance, the WTRU can determine this based on a pre-configured association between SSBs and CSI-RS resources (e.g., configured by RRC). The WTRU can determine the subset of CSI-RS to be measured based on SSB indications, and / or determine the optimal SSB based on the SSB measurements performed. The subset of CSI-RS can be indicated (e.g., explicitly, using a pointer to one of multiple subsets) in a random access response and / or can be indicated implicitly (e.g., when a RAR is received, the WTRU enables the subset of CSI-RS based on the reported or indicated SSB).

[0156] Alternatively or additionally, when the WTRU receives a PDCCH command that triggers early TA acquisition, the WTRU may enable a subset of CSI-RS measurements. In response to the PRACH preamble transmission for TA acquisition, the RAR and / or MAC CE containing the TA may activate the configured authorization. CSI-RS measurements can be configured ad hocly. For example, the WTRU may activate CSI-RS measurements for a specific time period and / or a specific number of reports. The time period and / or the number of reports can be configured and / or predefined. For example, the WTRU may deactivate CSI-RS measurements when the optimal SSB changes and / or when the SSB and / or CSI-RS measurements fall below a threshold.

[0157] Configuration authorization activation may exist. The WTRU may receive, for example, an indication to activate authorization from (e.g., or) a source cell and / or a target cell. This indication and / or authorization may include one or more of the following: Type 2 configuration authorization (e.g., where a first cell can configure authorization and / or a second cell can activate authorization), explicit authorization (e.g., a direct indication of the authorization to be used), and / or a pointer to one or more pre-configured authorizations (e.g., previously configured by RRC). The authorization indication may include a pointer to a configuration authorization, such as corresponding to a reported SSB. The authorization indication may include an indication of a set of configuration authorizations, such as corresponding to multiple CSI-RS associated with a reported SSB. Configuration authorization activation may be received in one or more of the following: a PDCCH command (e.g., triggering TA acquisition), a MAC CE (e.g., triggering LTM), and / or a RAR (e.g., received from a source or target, containing a TA value to be used for RACH-free handover). The WTRU may activate configuration authorization (e.g., autonomously), such as conditionally. For example, the WTRU may activate authorization by triggering any LTM described herein.

[0158] WTRU-based calculation reports may exist. WTRU can trigger events, such as when the TA acquisition of WTRU has been completed. For example, when the TA has been acquired based on WTRU measurements, WTRU may transmit one or more of the following uplink indications to the source cell and / or candidate cell: MAC CR, CSI, and / or other uplink indications.

[0159] The WTRU can trigger events based on measurement criteria (e.g., RSRP or any other trigger herein), and / or, for example, if a TA has already been (e.g., additionally) acquired, can (e.g., only) send a corresponding report. The TA can be acquired and / or available due to a previous WTRU-based TA acquisition. Reporting and / or LTM execution triggering caused by measurement-based events and / or triggers can be delayed until the WTRU-based TA acquisition is complete. A measurement event (e.g., beam RSRP above a threshold) can cause the WTRU to initiate a WTRU-based TA acquisition. For example, a trigger can (e.g., then) be executed when a measurement event can be satisfied and / or a TA can be acquired (e.g., both).

[0160] For example, in response to receiving a report from the WTRU (e.g., that a WTRU-based TA acquisition and / or beam or cell measurement has been performed above a threshold), the network can transmit a command to the WTRU to enable conditional LTM evaluation. The network can transmit the command to enable conditional LTM evaluation in the MAC CE. The WTRU can receive the command and / or (e.g., then) enable conditional LTM evaluation. Additionally or alternatively, the WTRU can enable conditional LTM evaluation based on the content of the command, such as based on determining one or more measurement conditions.

[0161] Beam stability may exist. The WTRU can determine beam stability assessments for one or more target / candidate cells or beams and / or source / serving cells. For example, BFD can be enabled on beams belonging to candidate cells. Additionally or alternatively, the WTRU may consider metrics related to BFD monitoring when determining whether to trigger a report and / or trigger LTM execution. The WTRU can monitor beam stability on one or more targets, such as when assessing conditional LTM triggering. The WTRU can (e.g., then) select the most stable target, for example, based on beam stability assessments. The WTRU can abort ongoing conditional LTM reconfiguration and / or execution. For example, when the target cell beam stability is below a threshold, the WTRU can select a different cell (e.g., including the source cell in some solutions).

[0162] Beam stability determination allows the WTRU to perform different actions. For example, if the beam stability of the selected target cell is below a threshold, the WTRU can perform LTM based on meeting the triggering criteria. If the beam stability is above the threshold, the WTRU can perform different procedures. For example, if the beam stability is above the threshold, the WTRU can use a higher initial transmission power, more PDU repetitions, different Hybrid Automatic Repeat Request (HARQ) transmission modes, and / or different random access procedures (e.g., 2-step or 4-step Random Access Channel (RACH), no RACH).

[0163] The WTRU can compare the beam stability of the source / serving cell and / or beam with that of the target cell and / or beam. Based on, for example, the relative beam stability between the source and the target, the WTRU can apply different conditions. For example, if the beam stability on the source is better than that on the target, then a higher RSRP threshold can then be used to trigger LTM. Conversely, if the beam stability on the target is better, then (e.g., then) a lower RSRP threshold can be used. In some examples, the WTRU can (e.g., therefore) determine the optimal cell that might have a lower cell quality measurement, for example, based on the fact that its beam stability is better than that of a cell with a higher cell quality measurement.

[0164] Beam stability determination can be based on one or more of the following: beam change statistics (e.g., the frequency of the best beam change on the cell, for example, within a specific time period), BFI count (e.g., the number of BFIs detected within a specific time period), BFD count (e.g., the number of BFIs detected within a specific time period), the rate of change and / or variance of individual beam measurements (e.g., the dB range of the best and / or worst beam measurements within a specific time period) and / or the number of beams above a threshold.

[0165] The WTRU can report information about beam stability of one or more target cells and / or beams to the source and / or target cells, for example, in MAC CE and / or CSI reports. This information can be used by the network, for example, to improve Radio Resource Management (RRM) parameters and / or performance, and / or to train artificial intelligence (AI) models. In some examples, reporting can be performed (e.g., only) after certain conditions are met, such as (e.g., only) when beam stability meets a specific criterion. For example, beam stability information can be reported to the target if a problem is detected on the target during evaluation. In some examples, for example, beam stability information can be reported to the target if a problem is detected on the source, and / or if LTM to the target is successful.

[0166] L1 events may exist. To support explicit LTM (e.g., using MAC CE to explicitly indicate cell changes) and / or conditional LTM (e.g., WTRU evaluation conditions for triggering cell changes), event-triggered L1 measurements can be defined. Periodic and / or non-periodic L1 reporting (e.g., using CSI reporting) may exist. Additionally or alternatively, L3 measurement reporting may support periodic and / or event-triggered reporting. For example, if it is determined that pre-configured event criteria (e.g., A3, A4, and / or etc.) have been met, the WTRU can report using RRC measurement reporting. Based on L3 filtered measurements (e.g., cell or beam measurements), it can be determined that pre-configured event criteria have been met.

[0167] Due to the associated delays, such as those associated with the transmission of L3 filtering and / or RRC reports for measurements, this document discloses event-triggered L1 reporting. L1 reports can be transmitted in CSI reports and / or other reports on PUCCH, and / or can be transmitted using MACCE and / or other upper-layer signaling methods. L1 measurement evaluation can be performed using unfiltered beam measurements at L1. Additionally or alternatively, new filtering methods can be defined, for example, at L1, in MAC, and / or in RRC (e.g., RRC using shorter and / or faster filtering than currently defined). New event triggering criteria can be used and / or events defined in L3 can be modified to support faster triggering and / or alternative triggering conditions, such as those based on L1 measurements.

[0168] L1 triggering can be evaluated based on one or more of SSB measurements, CSI-RS measurements, and / or combinations of measurements of both types of resources. For example, an average measurement can be derived using one or more SSB and / or CSI-RS measurements. A counter and / or time window can be used, additionally or alternatively, with the use of trigger time (TTT). TTT can specify the minimum amount of time a condition must be met before a triggering event. For example, unfiltered and / or L1 beam measurements using a shorter filter time than L3 measurements may be more unstable and / or fluctuate faster than long-term filtered measurements. The number of times an L1 measurement meets a criterion within a specific time period (e.g., in this case) can be counted, for example, rather than meeting the condition continuously over a specific duration (e.g., as with TTT).

[0169] Beam quality measurements can be compared to absolute and / or relative thresholds. For example, if a measurement exceeds the threshold N times within time X, an event can then be triggered. The relative beam quality of a source cell and / or one or more beams on the source cell can be compared to that of a target cell and / or one or more beams on the target cell. For example, if it is determined that the target cell is superior to the source cell N times within time X (e.g., including offset or hysteresis—e.g., source measurement + offset / hysteresis < target measurement), then (e.g., then) an event can be triggered. In some examples, an L1 event can be triggered if more than one condition is met. Conditions can include target beam / cell measurements being above a threshold and / or source measurements being below a threshold. Conditions can include meeting cell / beam quality criteria and / or the WTRU having used WTRU-based TA acquisition to obtain a TA value for the target cell. Conditions can include meeting time and / or distance criteria (e.g., events D1, D2, and / or T1) and / or meeting cell / beam quality criteria. Conditions can include meeting L1 beam measurement criteria and / or meeting L3 filtered beam / cell measurement criteria. Any combination of one or more standards, such as those described herein, may be used.

[0170] Adaptive and / or combined measurement criteria may exist. A WTRU can be configured with more than one measurement, measurement criterion, and / or measurement condition, for example, to be used when determining triggering for a conditional LTM. For example, conditional LTM triggering may use L3-based conditions (e.g., measurement events) and / or L1-based conditions. In some examples, two conditions may be satisfied for WTRU-triggered LTM. For example, an L3 event (e.g., event A3 and / or any other existing event type) may be satisfied using a cell quality measurement (e.g., long-term L3 filtering). Additionally or alternatively, an L1 beam measurement criterion may be satisfied (e.g., short-term conditions using a new L1 event).

[0171] In some examples, the output or result of one of the first and / or second measurement types may affect the operation and / or evaluation of other measurement types. For example, parameters used in a second type of measurement evaluation can be modified based on the output of a first measurement evaluation. L1 beam measurements may meet criteria, such as beam RSRP (e.g., SSB and / or CSI-RS) measurements exceeding a threshold once or multiple times. Cell quality measurement thresholds can be set based on, for example, beam measurements (e.g., the highest beam measurement and / or average beam measurement over a time period). Cell quality measurements can be set to be X dB below the beam measurement.

[0172] The WTRU can (e.g., then) check whether the currently filtered cell quality is above a threshold. This check may not utilize trigger time, for example, because the filtered cell quality can be derived from the current measurement and / or previous measurements (e.g., it has been averaged over time). For example, if the cell quality measurement (e.g., also) meets a criterion, then (e.g., then) a combined criterion can be met, and / or a measurement report and / or a conditional LTM can be triggered. For example, when beam measurement criteria are met, cell quality measurements can be used as a stability check. Cell quality measurements can be used as a stability check, for example, because cell quality (e.g., L3) measurements can provide an indication of the average quality over time. Additionally or alternatively, cell quality measurements can provide a stability metric, for example, while allowing for faster triggering based on L1 measurements without waiting for trigger time.

[0173] Multiple steps can be used to evaluate conditional LTM triggering. For example, L3 cell and / or beam quality measurements can be monitored (e.g., first). If the L3 measurement meets the triggering criteria (e.g., exceeds a threshold), then the L1 criteria can be evaluated (e.g., waiting or not waiting for the trigger time). If the L3 criteria continue to be met and / or (e.g., also) the L1 criteria (e.g., beam measurements exceed a threshold), then the combined conditional LTM triggering conditions can be determined (e.g., then). For example, when the L3 criteria are met, L1 triggering evaluation can be initiated. Using a combined criterion with separate L1 and L3 measurements, the criteria can be evaluated sequentially (e.g., L1 priority, or L3 priority) or in parallel / simultaneously. In some examples, as described herein, two types of measurements can be used for the first and / or second criteria.

[0174] For example, if a second measurement (e.g., L1) assessment is enabled by meeting a first (e.g., L3) criterion, a timer can be used to limit the amount of time the second criterion is evaluated. For example, if the second criterion is met within the time specified by the timer, a cell change (e.g., LTM) can then be triggered. For example, if the criterion is not met within the time specified by the timer, a report can be triggered. The report can be sent to a source indicating that the second criterion (e.g., L1 criterion) was not met, even if the first criterion (e.g., L3 criterion) was met. For example, the second criterion can be evaluated based on the meeting of the first criterion. Additionally or alternatively, the WTRU can be configured to (e.g., or) perform a cell change and / or report to a source based on whether the second criterion is met.

[0175] The first type of measurement can be used to select a target cell. The second type of measurement can be used to select a beam on (e.g., the selected) target cell. For example, if a cell quality threshold is met using L3 measurements, the WTRU can select the best beam belonging to that target cell and / or any beam on that target cell above the threshold (e.g., to perform conditional LTM). A disable timer can be used to prevent the WTRU from performing conditional cell handovers (e.g., too frequently). For example, when performing a conditional cell handover, the WTRU can be configured not to trigger any further cell handovers for the duration of the timer (e.g., even if measurement criteria are met). The WTRU can be configured to perform measurement reporting (e.g., periodic CSI reporting to the source cell) while the disable timer is running and / or (e.g., then) stop CSI reporting and / or perform conditional LTM assessments after the timer expires.

[0176] The trigger time can be extended, for example, after triggering a conditional LTM. For instance, a new target cell might meet criteria for a certain TTT. For example, if a cell handover occurs within X seconds after a new conditional LTM trigger is met, then (e.g., then) a criterion for TTT x 2 (e.g., or any configurable or fixed value—1.5, 3, etc.) can be met. The TTT used for conditional LTM can be scaled based on beam stability metrics. For example, a higher number of beam handovers within a specific timeframe might increase the TTT used to determine the cell handover.

[0177] The mobility assessment process can be selected, for example, based on a measurement type. For instance, a measurement event can be used if beam stability is below a certain threshold. A second measurement event can be used if beam stability is above a certain threshold. Additionally or alternatively, selection can be performed based on one or more of velocity, position, time, and / or any quality measurements and / or triggers described herein.

[0178] Figure 6 Example 600 illustrates a conditional standard modification of network control based on a second standard reported according to a first standard. WTRU 602 may receive one or more of the following: configuration of LTM candidate cells and / or conditional LTM configuration, including L1 conditions based on L1 measurements and associated L3 conditions based on L3 filtering measurements. For example, at 608, WTRU 602 may receive an RRC reconfiguration message from cell A 604. At 610, WTRU 602 may send an RRC reconfiguration complete message to cell A 604. WTRU performs a first type of measurement and / or evaluates first measurement conditions for candidate LTM cells. For example, WTRU may perform L1 beam measurements and / or evaluate based on a first standard for beams (e.g., measurement resources such as SSB, CSI-RS). The first standard may be based on any example provided herein (e.g., SSB / CSI-RS measurements meeting thresholds, WTRU acquisition of TA, beam stability, and / or so on).

[0179] For example, based on meeting the first criterion, WTRU 602 can trigger an L1 report to indicate to the network that the criterion is met. The L1 report can be transmitted in one or more of a MAC CE and / or CSI report, for example, at 612, WTRU 602 can send an L1 report to cell A 604. WTRU 602 can (e.g., then) receive commands to update and / or enable a second measurement type and / or criterion (e.g., L3 cell quality criterion). At 614, WTRU 602 can receive commands (e.g., MAC CE, C-LTM modification). For example, if the first criterion continues to be met and / or the second criterion is met, then (e.g., then) WTRU 602 can initiate and / or trigger an LTM cell handover. For example, at 616, WTRU 602 can trigger an LTM cell handover to cell B 606.

[0180] Figure 7Example 700 of a WTRU autonomous conditional standard modification based on a second standard reported according to a first standard is shown. WTRU 702 may receive one or more of the following: configuration of LTM candidate cells, conditional LTM configuration, including L1 conditions based on L1 measurements and associated L3 conditions based on L3 filtering measurements. For example, at 708, WTRU 702 may receive an RRC reconfiguration message from cell A 704. At 710, WTRU 702 may send an RRC reconfiguration complete message to cell A 704. WTRU 702 may perform a first type of measurement and / or evaluate first measurement conditions for candidate LTM cells. For example, WTRU 702 may perform L1 beam measurements and / or evaluate based on a first standard for beams (e.g., measurement resources such as SSB, CSI-RS). The first standard may be based on any example provided herein (e.g., SSB / CSI-RS measurements meeting thresholds, WTRU acquisition of TA, beam stability, and / or so on).

[0181] Based on meeting the first criterion, WTRU 702 can enable a second measurement type and / or criterion, such as the L3 cell quality criterion. For example, at 712, cell B 706 can send a message to WTRU 702 including cell B measurement and / or evaluation information. For example, if the first criterion continues to be met and / or the second criterion is met, then (e.g., then) WTRU 702 can initiate and / or trigger an LTM cell handover. At 714, cell B 706 can send a message to WTRU 702 including cell B measurement and / or evaluation information (e.g., updates thereto). At 716, WTRU 702 can trigger an LTM cell handover to cell B 706.

[0182] The first measurement can be a cell quality measurement (e.g., L3 cell quality). Examples (e.g., L3) cell quality measurements may include RSRP, Reference Signal Received Quality (RSRQ), Signal-to-Interference-Noise Ratio (SINR), and / or RSSI. For example, when the target cell meets a first criterion (e.g., the target cell is above a threshold), the WTRU can autonomously enable L1 beam measurements for the target cell. For example, the WTRU can select a subset of configured L1 beams associated with the target cell based on the beams selected during L3 beam selection for cell quality derivation. The WTRU can perform measurements and / or evaluate LTM triggering on the selected target cell beams, for example, based on maintaining cell quality above a threshold and / or beam quality satisfying L1 triggering conditions. The L3 threshold can be set to a relatively low value, for example, to ensure minimal measurement stability. The threshold may be lower than a threshold configured to support L3 handover, such that, for example, target cell quality (e.g., alone) may be insufficient to indicate triggering a handover. For example, when combined with L1 measurement triggering, L3 quality can provide an indication of stability. L1 measurements can provide a sufficiently high indicator of beam quality to trigger LTM.

[0183] Figure 8 Example 800 of an L1-triggered beam stability report for explicit LTM is shown. WTRU 802 can receive configurations of LTM candidate cells and / or event-triggered L1 measurement report configurations. For example, at 808, WTRU 802 can receive RRC reconfiguration from cell A 804. At 810, WTRU 802 can send an RRC reconfiguration complete message to cell A 804. Event-triggered L1 measurements can use any conditions detailed herein, such as beam stability measurements. For example, as described herein, WTRU 802 can perform L1-based measurements on one or more target cells and / or beams. For example, when criteria are met, reports can be transmitted to the network (e.g., using MAC CE and / or CSI reports).

[0184] Based on meeting the first criterion, WTRU 802 can enable a second measurement type and / or criterion, such as the L3 cell quality criterion. For example, at 812, cell B 806 can send a message to WTRU 802 including cell B measurement and / or evaluation information. At 814, WTRU 802 can transmit an L1 measurement report to cell A. At 814, WTRU 802 can receive a MAC CE and / or C-LTM modification. For example, if the first criterion continues to be met and / or the second criterion is met, then (e.g., then) WTRU 802 can initiate and / or trigger an LTM cell handover. Additionally or alternatively, at 816, WTRU can receive an LTM trigger from cell A 804, for example, in a MAC CE. At 816, WTRU 802 can trigger an LTM cell handover to cell B 806.

[0185] Figure 9 Example 900 is a WTRU-based TA measurement report used for (e.g., conditional and / or explicit) LTM preparation. WTRU 902 can receive configurations for LTM candidate cells and / or event-triggered L1 measurement report configurations. WTRU 902 can additionally or alternatively receive conditional LTM configurations. For example, at 904, WTRU 902 can receive an RRC reconfiguration message from cell A. At 910, WTRU 902 can send an RRC reconfiguration complete message to cell A 904. Event-triggered L1 measurements can use any conditions detailed herein, such as beam stability measurements. WTRU 902 can additionally or alternatively receive configurations to perform WTRU-based TA acquisition. WTRU 902 can perform L1-based measurements on one or more target cells and / or beams, for example, as detailed herein.

[0186] Based on meeting the first criterion, WTRU 902 can enable a second measurement type and / or criterion, such as the L3 cell quality criterion. For example, at 912, cell B 906 can send a message to WTRU 902 including cell B measurement and / or evaluation information. WTRU 902 can additionally or alternatively perform TA acquisition on the target cell. For example, when WTRU 902 successfully acquires a TA value from the target cell and / or when one or more criteria are met, WTRU 902 can trigger an L1 report to the source cell. For example, at 914, WTRU 902 can send an L1 report to cell A 904. WTRU can (e.g., then) receive explicit LTM triggers and / or triggers used to perform conditional LTM trigger evaluation. For example, at 916, WTRU 902 can receive an LTM trigger from cell A 904. At 918, WTRU 902 can trigger an LTM cell handover to cell B 906.

Claims

1. A wireless transmit / receive unit (WTRU), comprising: The processor is configured as follows: Receive first configuration information, the first configuration information including an indication of a first condition associated with one or more candidate layer trigger mobility (LTM) cells; The first condition is met; Receive second configuration information, which includes an indication of a second condition associated with the one or more candidate LTM cells; The second condition is confirmed to be met; as well as Based on the determination that the second condition is met, an indication is sent to the selected cell among the one or more candidate LTM cells.

2. The WTRU according to claim 1, wherein, The first condition includes a layer 1 condition, wherein the processor is configured as follows: Perform Layer 1 measurements associated with the one or more candidate LTM cells, and Compare the layer 1 measurements with the layer 1 conditions.

3. The WTRU according to claim 2, wherein, Layer 1 measurements include one or more of the following: Reference Signal Received Power (RSRP) or Received Signal Strength Indication (RSSI) associated with one or more cells or beams.

4. The WTRU of claim 2, wherein the layer 1 measurement includes a first layer 1 measurement, and the layer 1 condition includes a first layer 1 condition, and wherein the processor is configured to: Perform a second-layer 1 measurement associated with the one or more candidate LTM cells, and Compare the measurements of Layer 1 with the conditions of Layer 1; and Based on the comparison between the first layer 1 measurement and the first layer 1 condition, and the comparison between the second layer 1 measurement and the second layer 1 condition, it is determined that the first condition is met.

5. The WTRU according to claim 2, wherein, Layer 1 conditions include thresholds associated with one or more of the following: System Information Block (SSB) value, Channel State Information (CSI)-Reference Signal (RS) value, Timing Advance (TA) value, or Beam Stability value.

6. The WTRU according to claim 1, wherein, The second condition includes a layer 3 condition, wherein the processor is configured as follows: Perform Layer 3 measurements associated with the one or more candidate LTM cells, and Compare layer 3 measurements with layer 3 conditions.

7. The WTRU according to claim 6, wherein, Layer 3 measurements include filtering measurements associated with one or more cells or beams.

8. The WTRU according to claim 1, wherein, The processor is configured to determine that the first condition is met after receiving the second configuration information.

9. The WTRU according to claim 1, wherein, The processor is configured to send an indication to select a cell from the one or more candidate LTM cells after determining that a first condition has been met, based on a time limit.

10. The WTRU according to claim 1, wherein, The processor is configured as follows: Receive instructions to modify the first condition; Based on the instructions, modify the first condition; and Based on the modification of the first condition, it is determined that the first condition is satisfied.

11. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: Receive first configuration information, the first configuration information including an indication of a first condition associated with one or more candidate layer trigger mobility (LTM) cells; The first condition is met; Receive second configuration information, which includes an indication of a second condition associated with the one or more candidate LTM cells; The second condition is confirmed to be met; as well as Based on the determination that the second condition is met, an indication is sent to the selected cell among the one or more candidate LTM cells.

12. The method of claim 11, wherein the first condition includes a layer 1 condition, and wherein the method comprises: Perform Layer 1 measurements associated with the one or more candidate LTM cells, and Compare the layer 1 measurements with the layer 1 conditions.

13. The method according to claim 12, wherein, Layer 1 measurements include one or more of the following: Reference Signal Received Power (RSRP) or Received Signal Strength Indication (RSSI) associated with one or more cells or beams.

14. The method of claim 12, wherein the layer 1 measurement includes a first layer 1 measurement, and the layer 1 condition includes a first layer 1 condition, and wherein the method comprises: Perform a second-layer 1 measurement associated with the one or more candidate LTM cells, and Compare the second layer 1 measurement with the second layer 1 condition; as well as Based on the comparison between the first layer 1 measurement and the first layer 1 condition, and the comparison between the second layer 1 measurement and the second layer 1 condition, it is determined that the first condition is met.

15. The method according to claim 12, wherein, Layer 1 conditions include thresholds associated with one or more of the following: System Information Block (SSB) value, Channel State Information (CSI)-Reference Signal (RS) value, Timing Advance (TA) value, or Beam Stability value.

16. The method of claim 11, wherein the second condition includes a layer 3 condition, and wherein the method comprises: Perform Layer 3 measurements associated with the one or more candidate LTM cells, and Compare layer 3 measurements with layer 3 conditions.

17. The method according to claim 16, wherein, Layer 3 measurements include filtering measurements associated with one or more cells or beams.

18. The method of claim 11, further comprising determining that a first condition is satisfied after receiving the second configuration information.

19. The method of claim 11, further comprising sending an indication for selecting a cell from the one or more candidate LTM cells after determining that a first condition has been met, based on a time limit.

20. The method of claim 11, comprising: Receive an instruction to modify the first condition; Based on the instructions, modify the first condition; as well as Based on the modification of the first condition, it is determined that the first condition is satisfied.

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