Methods, architectures, apparatuses and systems for timing advance prediction in artificial intelligence / machine learning (AIML) systems

Abstract

Procedures, methods, architectures, apparatuses, systems, devices, and computer program products for timing advance prediction are provided. One method may include performing a prediction of a timing advance (TA), and determining a difference between a value of the predicted TA and one or more of previously predicted TA values or network-configured TA values. On condition that the difference is larger than a configured threshold, the method may include determining to use the predicted TA for a next uplink transmission and sending, to the network, information associated with the predicted TA.

Description

METHODS, ARCHITECTURES, APPARATUSES AND SYSTEMS FOR TIMING ADVANCE PREDICTION IN ARTIFICIAL INTELLIGENCE / MACHINE LEARNING (AIML) SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 546,379 filed October 30, 2023, U.S. Provisional Patent Application No. 63 / 546,380 filed October 30, 2023, and U.S. Provisional Patent Application No. 63 / 546,382 filed October 30, 2023, which are incorporated herein by reference in their entirety.FIELD

[0002] Example embodiments described in the present disclosure are generally directed to the fields of communications, software and / or encoding, including, for example, to methods, architectures, apparatuses, systems related to timing advance prediction.BACKGROUND

[0003] Artificial intelligence (Al) may be broadly defined as the behavior exhibited by machines. Such behavior may, for example, mimic cognitive functions to sense, reason, adapt and / or act. Machine learning (ML) may refer to the types of algorithms that solve a problem based on learning through experience, without explicitly being programmed. ML can be considered as a subset of Al. It is expected that Artificial Intelligence (AI) / Machine Learning (ML) may be applied for new radio (NR) air interface. One of the use-cases for AI / ML for air interface is beam management. This approach can be a great foundation for improving performance and complexity in conventional beam management aspects, including beam prediction in time, and / or spatial domain for overhead and latency reduction, beam selection accuracy improvement, and so forth.SUMMARY

[0004] Some embodiments may be directed to a method implemented in a wireless transmit / receive unit (WTRU). The method may include determining a timing advance (TA) value based on one or more input values, determining a difference between the determined TA value and any of (1) one or more previously determined TA values and (2) network-configured TA values and, on condition that the difference is larger than a configured threshold, determining to use the determined TA value for a next uplink transmission. The method may further include sending, to the network, information associated with the determined TA value.

[0005] In an embodiment, the determining of the TA value comprises predicting the TA value based on the one or more input values.

[0006] In an embodiment, the one or more input values comprise any of: (1) a time delay, (2) a transmission time stamp of one or more signals, (3) synchronization signal block (SSB) measurements at a serving cell and / or neighbor cells, (4) a mapping table associating neighbor cell measurements, serving cell measurements and / or TAs, and (5) based on an output of an artificial intelligence / machine learning (AI / ML) model.

[0007] In an embodiment, the determining of the TA value is initiated based on any of: a status of the time alignment timer (TAT), a status of traffic activity, a status of mobility, and receiving configuration information indicating to initiate the performing of the TA prediction.

[0008] In an embodiment, the information associated with the determined TA comprises an indication of any of: (1) the determined TA, (2) the difference between the value of the determined TA value and the any of the one or more previously predicted TA values and the network- configured TA values, and (3) a TA adjustment applied by the WTRU.

[0009] In an embodiment, the information associated with the determined TA value is sent to the network via any of: a timing advance report (TAR), as part of a channel state information (CSI) report, physical uplink shared channel (PUSCH), hybrid automatic repeat request (HARQ)- acknowledgement (ACK) codebook, medium access control (MAC)-control element (CE), and / or uplink control information (UCI) physical uplink control channel (PUCCH) transmission.

[0010] In an embodiment, the information associated with the determined TA value is sent in a next uplink transmission.

[0011] In an embodiment, the next uplink transmission comprises any of: sounding reference signal (SRS), configured uplink grant, dynamic uplink grant, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), physical random access channel (PRACH), and scheduling request (SR).

[0012] In an embodiment, the method includes, on condition that the difference is larger than the configured threshold, restarting a time alignment timer (TAT) or starting the TAT with a determined or configured TAT value.

[0013] In an embodiment, the method includes receiving an indication to stop, disable or deactivate the determining of the TA value.

[0014] In an embodiment, the method includes receiving, from the network, a confirmation to use the determined TA value.

[0015] In an embodiment, the determining of the TA value is based on one or more detected signals and an artificial intelligence / machine learning (AI / ML) model.

[0016] Some embodiments may be directed to a wireless transmit / receive unit (WTRU) that includes circuitry, including any of a processor, memory, receiver and / or transmitter, the circuitry configured to determine a timing advance (TA) value based on one or more input values, determine a difference between the determined TA value and any of (1) one or more previously determined TA values and (2) network-configured TA values and, on condition that the difference is larger than a configured threshold, determine to use the determined TA value for a next uplink transmission. The circuity may also be configured to send, to the network, information associated with the determined TA value.

[0017] In an embodiment, to determine the TA value, the circuitry is configured to predict the TA value based on the one or more input values, wherein the one or more input values comprise any of: (1) a time delay, (2) a transmission time stamp of one or more signals, (3) synchronization signal block (SSB) measurements at a serving cell and / or neighbor cells, (4) a mapping table associating neighbor cell measurements, serving cell measurements and / or TAs, and (5) based on an output of an artificial intelligence / machine learning (AI / ML) model.

[0018] In an embodiment, the circuitry is configured to initiate the determination of the TA value based on any of: a status of the time alignment timer (TAT), a status of traffic activity, a status of mobility, and receiving configuration information indicating to initiate the performing of the TA prediction.

[0019] In an embodiment, the information associated with the determined TA comprises an indication of any of: (1) the determined TA, (2) the difference between the value of the determined TA value and the any of the one or more previously predicted TA values and the network- configured TA values, and (3) a TA adjustment applied by the WTRU.

[0020] In an embodiment, the information associated with the determined TA value is sent to the network via any of: a timing advance report (TAR), as part of a channel state information (CSI) report, physical uplink shared channel (PUSCH), hybrid automatic repeat request (HARQ)- acknowledgement (ACK) codebook, medium access control (MAC)-control element (CE), and / or uplink control information (UCI) physical uplink control channel (PUCCH) transmission.

[0021] In an embodiment, the information associated with the determined TA value is sent in a next uplink transmission.

[0022] In an embodiment, the next uplink transmission comprises any of: sounding reference signal (SRS), configured uplink grant, dynamic uplink grant, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), physical random access channel (PRACH), and scheduling request (SR).

[0023] In an embodiment, the circuitry is configured to, on condition that the difference is larger than the configured threshold, restart a time alignment timer (TAT) or start the TAT with a determined or configured TAT value.

[0024] In an embodiment, the circuitry is configured to receive an indication to stop, disable or deactivate the determination of the TA value.

[0025] In an embodiment, the circuitry is configured to receive, from the network, a confirmation to use the determined TA value.

[0026] In an embodiment, the circuitry is configured to determine the TA value based on one or more detected signals and an artificial intelligence / machine learning (AI / ML) model.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] A more detailed understanding may be had from the detailed description below, given by way of example in conjunction with drawings appended hereto. Figures in such drawings, like the detailed description, are examples. As such, the Figures (FIGs.) and the detailed description are not to be considered limiting, and other equally effective examples are possible and likely. Furthermore, like reference numerals ("ref.") in the FIGs. indicate like elements, and wherein:

[0028] FIG. 1 A is a system diagram illustrating an example communications system;

[0029] FIG. IB is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1 A;

[0030] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A;

[0031] FIG. ID is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1 A;

[0032] FIG. 2A illustrates an example of an AIML system for timing advance prediction, according to an embodiment;

[0033] FIG. 2A illustrates an example of an AIML system for timing advance prediction, according to another embodiment;

[0034] FIG. 3 illustrates an example flow chart of a method, according to an embodiment;

[0035] FIG. 4 illustrates an example flow chart of a method, according to an embodiment; and

[0036] FIG. 5 illustrates an example flow chart of a method, according to an embodiment.DETAILED DESCRIPTION

[0037] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments and / or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components and circuits have not been described in detail, so as not to obscure the following description. Further, embodiments and examples not specifically described herein may be practiced in lieu of, or in combination with, the embodiments and other examples described, disclosed or otherwise provided explicitly, implicitly and / or inherently (collectively "provided") herein. Although various embodiments are described and / or claimed herein in which an apparatus, system, device, etc. and / or any element thereof carries out an operation, process, algorithm, function, etc. and / or any portion thereof, it is to be understood that any embodiments described and / or claimed herein assume that any apparatus, system, device, etc. and / or any element thereof is configured to carry out any operation, process, algorithm, function, etc. and / or any portion thereof.

[0038] The methods, apparatuses and systems provided herein are well-suited for communications involving both wired and wireless networks. An overview of various types of wireless devices and infrastructure is provided with respect to FIGs. 1A-1D, where various elements of the network may utilize, perform, be arranged in accordance with and / or be adapted and / or configured for the methods, apparatuses and systems provided herein.

[0039] FIG. 1A is a system diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), singlecarrier FDMA (SC-FDMA), zero-tail (ZT) unique-word (UW) discreet Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block- filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0040] As shown in FIG. 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104 / 113, a core network (CN) 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a "station" and / or a "STA", may be configured to transmit and / or receive wireless signals and may include (or be) a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi- Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d, or any other WTRU mentioned or described herein, may be interchangeably referred to as a UE.

[0041] The communications systems 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d, e.g., to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or the networks 112. By way of example, the base stations 114a, 114b may be any of a base transceiver station (BTS), a Node-B (NB), an eNode-B (eNB), a Home Node-B (HNB), a Home eNode-B (HeNB), a gNode-B (gNB), a NR Node-B (NR NB), a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0042] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in an embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO)technology and may utilize multiple transceivers for each or any sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0043] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0044] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) and / or High-Speed Uplink Packet Access (HSUPA).

[0045] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE- Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0046] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access, which may establish the air interface 116 using New Radio (NR).

[0047] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., an eNB and a gNB).

[0048] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (Wi-Fi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0049] The base station 114b in FIG. 1 A may be a wireless router, Home Node-B, Home eNode- B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish any of a small cell, picocell or femtocell. As shown in FIG. 1 A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106 / 115.

[0050] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 / 115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1 A, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may be utilizing an NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing any of a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or Wi-Fi radio technology.

[0051] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and / or the internet protocol (IP) in the TCP / IP internet protocol suite. The networks 112 may include wired and / or wireless communications networks owned and / or operated by other service providers. For example, the networks 112 may include another CNconnected to one or more RANs, which may employ the same RAT as the RAN 104 / 114 or a different RAT.

[0052] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0053] FIG. IB is a system diagram illustrating an example WTRU 102. As shown in FIG. IB, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other elements / peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0054] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. IB depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together, e.g., in an electronic package or chip.

[0055] The transmit / receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in an embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In an embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0056] Although the transmit / receive element 122 is depicted in FIG. IB as a single element, the WTRU 102 may include any number of transmit / receive elements 122. For example, the WTRU 102 may employ MIMO technology. Thus, in an embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0057] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit / receive element 122 and to demodulate the signals that are received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11, for example.

[0058] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), readonly memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0059] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0060] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0061] The processor 118 may further be coupled to other elements / peripherals 138, which may include one or more software and / or hardware modules / units that provide additional features, functionality and / or wired or wireless connectivity. For example, the elements / peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (e.g., for photographs and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The elements / peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0062] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the uplink (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and / or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the uplink (e.g., for transmission) or the downlink (e.g., for reception)).

[0063] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0064] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0065] Each of the eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handoverdecisions, scheduling of users in the uplink (UL) and / or downlink (DL), and the like. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0066] The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any one of these elements may be owned and / or operated by an entity other than the CN operator.

[0067] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an SI interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0068] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via the SI interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter-eNode-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0069] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0070] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers.

[0071] Although the WTRU is described in FIGs. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0072] In representative embodiments, the other network 112 may be a WLAN.

[0073] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802. l ie DLS or an 802.1 Iz tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad-hoc" mode of communication.

[0074] When using the 802.1 lac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented, for example in in 802.11 systems. For CSMA / CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0075] High throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadj acent 20 MHz channel to form a 40 MHz wide channel.

[0076] Very high throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. The 40 MHz, and / or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse fast fourier transform (IFFT) processing, and time domain processing, may be done on each stream separately.The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above-described operation for the 80+80 configuration may be reversed, and the combined data may be sent to a medium access control (MAC) layer, entity, etc.

[0077] Sub 1 GHz modes of operation are supported by 802.1 laf and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.1 laf and 802.1 lah relative to those used in802.1 In, and 802.1 lac. 802.1 laf supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 802.1 lah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment,802.1 lah may support meter type control / machine-type communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and / or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0078] WLAN systems, which may support multiple channels, and channel bandwidths, such as802.1 In, 802.1 lac, 802.1 laf, and 802.1 lah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.1 lah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0079] In the United States, the available frequency bands, which may be used by 802.1 lah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.1 lah is 6 MHz to 26 MHz depending on the country code.

[0080] FIG. ID is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0081] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 180b may utilize beamforming to transmit signals to and / or receive signals from the WTRUs 102a, 102b, 102c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0082] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., including a varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0083] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with / connect to gNBs 180a, 180b, 180c while also communicating with / connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, 102c.

[0084] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and the like. As shown in FIG. ID, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0085] The CN 115 shown in FIG. ID may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and at least one Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0086] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b, e.g., to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and / or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0087] The SMF 183 a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an Ni l interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP -based, non-IP based, Ethernet-based, and the like.

[0088] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with accessto packet-switched networks, such as the Internet 110, e.g., to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0089] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers. In an embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0090] In view of FIGs. 1 A-1D, and the corresponding description of FIGs. 1 A-1D, one or more, or all, of the functions described herein with regard to any of: WTRUs 102a-d, base stations 114a- b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a- b, SMFs 183a-b, DNs 185a-b, and / or any other element(s) / device(s) described herein, may be performed by one or more emulation elements / devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0091] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and / or may performing testing using over-the-air wireless communications.

[0092] The one or more emulation devices may perform the one or more, including all, functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be testequipment. Direct RF coupling and / or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0093] Embodiments disclosed herein are representative and do not limit the applicability of the apparatus, procedures, functions and / or methods to any particular wireless technology, any particular communication technology and / or other technologies. The term network in this disclosure may generally refer to one or more base stations or gNBs or other network entity which in turn may be associated with one or more Transmission / Reception Points (TRPs), or to any other node in the radio access network.

[0094] It is noted that, throughout example embodiments described herein, the terms “serving base station”, “base station”, “gNB”, collectively “gNB” may be used interchangeably to designate any network element such as, e.g., a network element acting as a serving base station. Embodiments described herein are not limited to gNBs and are applicable to any other type of base stations.

[0095] As used herein, the terms ‘a’ and ‘an’ and similar phrases are to be interpreted as ‘one or more’ and ‘at least one’. Similarly, any term which ends with the suffix ‘(s)’ is to be interpreted as ‘one or more’ and ‘at least one’. The term ‘may’ is to be interpreted as ‘may, for example’. A symbol 7’ (e.g., forward slash) may be used herein to represent ‘and / or’, where for example, ‘A / B’ may imply ‘A and / or B’ . Herein, the terms prediction and estimation may be used interchangeably, but still consistent with example embodiments. Herein, the terms candidate cell, neighbor cell, and target cell may be used interchangeably, but still consistent with example embodiments. Herein, the terms source cell, current cell, and serving cell may be used interchangeably, but still consistent with example embodiments. Herein, the terms LTM command, LTM cell switch, LTM cell switch command, and cell switch command may be used interchangeably, but still consistent with this invention.

[0096] Artificial intelligence (Al) may be broadly defined as the behavior exhibited by machines. Such behavior may, for example, mimic cognitive functions to sense, reason, adapt and act.

[0097] Machine learning (ML) may refer to types of algorithms that solve a problem based on learning through experience (‘data’), without explicitly being programmed (‘configuring set of rules’). Machine learning can be considered as a subset of Al. Different machine learning paradigms may be envisioned based on the nature of data or feedback available to the learning algorithm. For example, a supervised learning approach may involve learning a function that maps input to an output based on a labeled training example, wherein each training example may be a pair consisting of input and the corresponding output. For example, an unsupervised learning approach may involve detecting patterns in the data with no pre-existing labels. For example, areinforcement learning approach may involve performing sequence of actions in an environment to maximize the cumulative reward. In some solutions, it is possible to apply machine learning algorithms using a combination or interpolation of the above-mentioned approaches. For example, a semi-supervised learning approach may use a combination of a small amount of labeled data with a large amount of unlabeled data during training. In this regard, semi-supervised learning falls between unsupervised learning (with no labeled training data) and supervised learning (with only labeled training data).

[0098] Deep learning refers to a class of machine learning algorithms that employ artificial neural networks (e.g., DNNs) which were loosely inspired from biological systems. The Deep Neural Networks (DNNs) are a special class of machine learning models inspired by the human brain where the input is linearly transformed and passed-through non-linear activation function multiple times. DNNs typically consists of multiple layers where each layer consists of linear transformation and a given non-linear activation functions. The DNNs can be trained using the training data via a back-propagation algorithm. Recently, DNNs have shown state-of-the-art performance in variety of domains, e.g., speech, vision, natural language etc. and for various machine learning settings supervised, un-supervised, and semi-supervised. The term AIML based methods or processing may refer to a realization of behaviors and / or conformance to requirements by learning based on data, without explicit configuration of sequence of steps of actions. Such methods may enable learning complex behaviors which might be difficult to specify and / or implement when using legacy methods.

[0099] As described herein, an AIML model may refer to an implementation of an AIML based method which is made up of (1) model parameters and (2) the model structure. For example, a DNN-based AIML model may include the model parameters (i.e., weights and biases) and the model structure (i.e., the types and sizes of each layer of the deep neural network such as dense layers, convolutional layers, etc.).

[0100] A WTRU may transmit or receive a physical channel or reference signal according to at least one spatial domain filter. The term “beam” may be used to refer to a spatial domain filter.

[0101] The WTRU may transmit a physical channel or signal using the same spatial domain filter as the spatial domain filter used for receiving an RS (such as CSLRS) or a SS block. The WTRU transmission may be referred to as “target”, and the received RS or SS block may be referred to as “reference” or “source”. In such a case, the WTRU may be said to transmit the target physical channel or signal according to a spatial relation with a reference to such RS or SS block.

[0102] The WTRU may transmit a first physical channel or signal according to the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel or signal. The first and second transmissions may be referred to as “target” and “reference” (or “source”),respectively. In such a case, the WTRU may be said to transmit the first (target) physical channel or signal according to a spatial relation with a reference to the second (reference) physical channel or signal.

[0103] A spatial relation may be implicit, configured by RRC or signaled by MAC CE or DCI. For example, a WTRU may implicitly transmit PUSCH and DM-RS of PUSCH according to the same spatial domain filter as an SRS indicated by an SRI indicated in DCI or configured by RRC. In another example, a spatial relation may be configured by RRC for an SRS resource indicator (SRI) or signaled by MAC CE for a PUCCH. Such spatial relation may also be referred to as a “beam indication”.

[0104] The WTRU may receive a first (target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (reference) downlink channel or signal. For example, such association may exist between a physical channel, such as PDCCH or PDSCH, and its respective DM-RS. At least when the first and second signals are reference signals, such association may exist when the WTRU is configured with a quasi-colocation (QCL) assumption type D between corresponding antenna ports. Such an association may be configured as a TCI (transmission configuration indicator) state. A WTRU may be indicated an association between a CSI-RS or SS block and a DM-RS by an index to a set of TCI states configured by RRC and / or signaled by MAC CE. Such indication may also be referred to as a “beam indication”.

[0105] Hereafter, a TRP (e.g., transmission and reception point) may be interchangeably referred to as one or more of TP (transmission point), RP (reception point), RRH (radio remote head), DA (distributed antenna), BS (base station), a sector (of a BS), and / or a cell (e.g., a geographical cell area served by a BS), while remaining consistent with example embodiments. Hereafter, Multi - TRP may be interchangeably used with one or more of MTRP, M-TRP, and multiple TRPs, but still consistent with example embodiments.

[0106] A WTRU may report a subset of channel state information (CSI) components, where CSI components may correspond to at least a CSI-RS resource indicator (CRI), a SSB resource indicator (SSBRI), an indication of a panel used for reception at the WTRU (such as a panel identity or group identity), measurements, such as Ll-RSRP and / or Ll-SINR taken from SSB or CSI-RS (e.g. cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR), and other channel state information such as at least rank indicator (RI), channel quality indicator (CQI), precoding matrix indicator (PMI), Layer Index (LI), and / or the like.

[0107] A WTRU may receive a synchronization signal / physical broadcast channel (SS / PBCH) block. The SS / PBCH block (SSB) may include a primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH). The WTRU may monitor,receive, or attempt to decode an SSB during initial access, initial synchronization, radio link monitoring (RLM), cell search, cell switching, and so forth.

[0108] A WTRU may measure and report the channel state information (CSI), wherein the CSI for each connection mode may include or be configured with one or more of following: (1) CSI Report Configuration (e.g., including one or more of the following: (i) CSI report quantity, e.g., Channel Quality Indicator (CQI), Rank Indicator (RI), Precoding Matrix Indicator (PMI), CSI-RS Resource Indicator (CRI), Layer Indicator (LI), etc.; (ii) CSI report type, e.g., aperiodic, semi persistent, periodic; (iii) CSI report codebook configuration, e.g., Type I, Type II, Type II port selection, etc.; and / or (iv) CSI report frequency); (2) CSLRS Resource Set (e.g., including one or more of the following CSI Resource settings: NZP-CSLRS Resource for channel measurement, NZP-CSLRS Resource for interference measurement, and / or CSI-IM Resource for interference measurement), and / or (3) NZP CSLRS Resources (e.g., including one or more of the following: NZP CSLRS Resource ID, Periodicity and offset, QCL Info and TCLstate, and / or Resource mapping, e.g., number of ports, density, CDM type, etc.).

[0109] A WTRU may indicate, determine, and / or be configured with one or more reference signals. The WTRU may monitor, receive, and / or measure one or more parameters based on the respective reference signals. For example, one or more of the parameters discussed in the following may apply. The following parameters are non-limiting examples of the parameters that may be included in reference signal(s) measurements: SS reference signal received power (SS-RSRP), CSLRSRP, SS signal-to-noise and interference ratio (SS-SINR), CSI-SINR, Received signal strength indicator (RS SI), Cross-Layer interference received signal strength indicator (CLI-RSSI), Sounding reference signals RSRP (SRS-RSRP), Secondary synchronization signal reference signal received quality (SS-RSRQ), and / or CSI reference signal received quality (CSI-RSRQ). One or more of these parameters may be included. Other parameters may additionally or alternatively be included.

[0110] SS-RSRP may be measured based on the synchronization signals (e.g., demodulation reference signal (DMRS) in PBCH or SSS). It may be defined as the linear average over the power contribution of the resource elements (RE) that carry the respective synchronization signal. In measuring the RSRP, power scaling for the reference signals may be required. In case SS-RSRP is used for Ll-RSRP, the measurement may be accomplished based on CSI reference signals in addition to the synchronization signals.[OHl] CSLRSRP may be measured based on the linear average over the power contribution of the resource elements (RE) that carry the respective CSLRS. The CSLRSRP measurement may be configured within measurement resources for the configured CSLRS occasions.

[0112] SS-SINR may be measured based on the synchronization signals (e.g., DMRS in PBCH or SSS). It may be defined as the linear average over the power contribution of the resource elements (RE) that carry the respective synchronization signal divided by the linear average of the noise and interference power contribution. In case SS-SINR is used for Ll-SINR, the noise and interference power measurement may be accomplished based on resources configured by higher layers.

[0113] CSI-SINR may be measured based on the linear average over the power contribution of the resource elements (RE) that carry the respective CSI-RS divided by the linear average of the noise and interference power contribution. In case CSI-SINR is used for Ll-SINR, the noise and interference power measurement may be accomplished based on resources configured by higher layers. Otherwise, the noise and interference power may be measured based on the resources that carry the respective CSI-RS.

[0114] RSSI may be measured based on the average of the total power contribution in configured OFDM symbols and bandwidth. The power contribution may be received from different resources (e.g., co-channel serving and non-serving cells, adjacent channel interference, thermal noise, and so forth).

[0115] CLLRSSI may be measured based on the average of the total power contribution in configured OFDM symbols of the configured time and frequency resources. The power contribution may be received from different resources (e.g., cross-layer interference, co-channel serving and non-serving cells, adjacent channel interference, thermal noise, and so forth).

[0116] SRS-RSRP may be measured based on the linear average over the power contribution of the resource elements (RE) that carry the respective SRS.

[0117] SS-RSRQ may be measured based on measurements on the reference signal received power (SS-RSRP) and received signal strength (RSSI). In an example, the SS-RSRQ may be calculated as the ratio of N*SS-RSRP / NR carrier RSSI, where N may be determined based on the number of resource blocks that are in the corresponding NR carrier RSSI measurement bandwidth. As such, the measurements to be used in the numerator and denominator may be over the same set of resource blocks.

[0118] CSLRSRQ may be measured based on measurements on the reference signal received power (CSLRSRP) and received signal strength (RSSI). In an example, the SS-RSRQ may be calculated as the ratio of N*CSI-RSRP / CSIRSSI, where N may be determined based on the number of resource blocks that are in the corresponding CSI-RSSI measurement bandwidth. As such, the measurements to be used in the numerator and denominator may be over the same set of resource blocks.

[0119] A CSI report configuration (e.g., CSI-ReportConfigs) may be associated with a single BWP (e.g., indicated by BWP-Id), wherein one or more of the following parameters are configured: CSI-RS resources and / or CSI-RS resource sets for channel and interference measurement; CSI-RS report configuration type (e.g., including the periodic, semi-persistent, and aperiodic); CSI-RS transmission periodicity for periodic and semi-persistent CSI reports; CSI-RS transmission slot offset for periodic, semi-persistent and aperiodic CSI reports; CSI-RS transmission slot offset list for semi-persistent and aperiodic CSI reports; Time restrictions for channel and interference measurements; Report frequency band configuration (wideband / subb and CQI, PMI, and so forth); Thresholds and modes of calculations for the reporting quantities (CQI, RSRP, SINR, LI, RI, etc.); Codebook configuration; Group based beam reporting; CQI table; Subband size; Non-PMI port indication; Port Index; and / or the like.

[0120] A CSI-RS Resource Set (e.g., NZP-CSI-RS-ResourceSet) may include one or more of CSI-RS resources (e.g., NZP-CSI-RS-Resource and CSI-ResourceConfig), wherein a WTRU may be configured with one or more of the following in a CSI-RS Resource: (1) CSI-RS periodicity and slot offset for periodic and semi-persistent CSI-RS Resources; (2) CSI-RS resource mapping to define the number of CSI-RS ports, density, CDM-type, OFDM symbol, and subcarrier occupancy; (3) the bandwidth part to which the configured CSI-RS is allocated; and / or (4) the reference to the TCLState including the QCL source RS(s) and the corresponding QCL type(s).

[0121] One or more of the following configurations may be used for RS resource set. For example, a WTRU may be configured with one or more RS resource sets in which the RS resource set configuration may include one or more of following: RS resource set ID, one or more RS resources for the RS resource set, repetition (i.e., on or off), aperiodic triggering offset (e.g., one of 0-6 slots), and / or TRS info (e.g., true or not).

[0122] One or more of the following configurations may be used for RS resource. For example, a WTRU may be configured with one or more RS resources. The RS resource configuration may include one or more of following: RS resource ID, resource mapping (e.g., REs in a PRB), power control offset (e.g., one value of -8, . . ., 15), power control offset with SS (e.g., -3 dB, 0 dB, 3 dB, 6 Db), scrambling ID, periodicity and offset, and / or QCL information (e.g., based on a TCI state).

[0123] In the following, a property of a grant or assignment may include at least one of the following: a frequency allocation; an aspect of time allocation, such as a duration; a priority; a modulation and coding scheme; a transport block size; a number of spatial layers; a number of transport blocks; a TCI state, CRI or SRI; a number of repetitions; whether the repetition scheme is Type A or Type B; whether the grant is a configured grant type 1, type 2 or a dynamic grant; whether the assignment is a dynamic assignment or a semi-persistent scheduling (configured) assignment; a configured grant index or a semi-persistent assignment index; a periodicity of aconfigured grant or assignment; a channel access priority class (CAPC); and / or any parameter provided in a DCI, by MAC or by RRC for the scheduling the grant or assignment.

[0124] In the following, an indication by DCI may include at least one of the following: an explicit indication by a DCI field or by RNTI used to mask or scramble the CRC of the DCI, and / or an implicit indication by a property, such as DCI format, DCI size, CORESET or search space, Aggregation Level, first resource element of the received DCI (e.g., index of first Control Channel Element), where the mapping between the property and the value may be signaled by RRC or MAC.

[0125] It is noted that receiving or monitoring for a DCI with or using an RNTI may mean that the CRC of the DCI is masked or scrambled with the RNTI.

[0126] A WTRU may perform measurements of serving and neighbor cells based on a configuration received by the gNB. The measurement configuration contains several elements such as the measurement object (what is to be measured, e.g., RAT, frequency, cells, reference signals, etc.), and a reporting configuration that indicates when the WTRU transmits the measurement reports (e.g., periodic reporting, event based reporting, etc.) and what to include in the report (e.g., reference signals to be reports, e.g., CSLRS or SSB, number of cells / beams to be reported, etc.).

[0127] There are several ways of configuring event triggered reporting, for example, these may include: Event Al (Serving cell becomes better than threshold), Event A2 (Serving becomes worse than threshold), Event A3 (Neighbor becomes offset better than SpCell), Event A4 (Neighbor becomes better than threshold), Event A5 (SpCell becomes worse than threshold 1 and neighbour becomes better than threshold2), Event A6 (Neighbor becomes offset better than SC ell), Event B 1 (Inter RAT neighbour becomes better than threshold), and Event B2 (PCell becomes worse than thresholdl and inter RAT neighbour becomes better than threshold2).

[0128] Here, the term SpCell may refer to a PCell (Primary Cell), or in the case of DC, the Primary Secondary Cell (PSCell). Event A3, A5, B2 can only be configured for the PCell or PSCell. Events Al, A2, A3, A5, B2 can be configured for any serving cell. Event A6 can be configured only for SCells (i.e., for the secondary cells in carrier aggregation (CA)). Events A4 and Bl are only related to neighbor cell measurements (and thus not related to any serving cell).

[0129] In addition to the threshold values, each event configuration is also associated with a hysteresis and time to trigger (TTT) parameters, to limit the number and / or frequency of ping pong handovers.

[0130] Though the network can instruct a WTRU to perform a handover to a neighbor cell at any time (e.g., due to load conditions in the current serving cell), typically, handover is triggered due to the reception of a measurement from the WTRU (e.g., UE sending a measurement report due tothe fulfillment of an A3 event, i.e., indicating that a neighbor cell has become better than the serving cell by a certain threshold).

[0131] When the WTRU receives a HO command (which may be or may include an RRC reconfiguration containing information about the target / neighbor cell), the WTRU will stop communicating with the serving cell, perform a random access (RA) procedure to the target cell to identify itself and also obtain the UL TA to use towards the target cell for future communications, apply the RRC reconfiguration that is the HO command, and send a HO complete message to the target cell. During the RA procedure to the target cell, there is an interruption of UL and DL user plane communication with the network, which is typically referred to as “handover interruption”.

[0132] If the measurement reports are not received in due time before the serving cell conditions get very bad (e.g., the WTRU goes out of coverage of the serving cell before it sends the measurement report), the WTRU may experience a radio link failure (RLF). If the measurement reports were sent on time but the WTRU goes out of coverage of the serving cell before the HO command is received, the WTRU may experience what is known as a Handover Failure (HOF).

[0133] In 3GPP Rel-16, LTE / NR introduced the concept of conditional handover (CHO) to address such RLFs and HOFs. In CHO, a WTRU is configured with a conditional measurement event, where the main difference from legacy measurement events is that instead of sending a measurement report when the event conditions are fulfilled, the WTRU executes a HO command that is associated with the event. The CHO command could be sent when the radio conditions towards the current serving cell is still favorable, thereby reducing the two main points of failure in legacy handover, i.e., risk failing to send the measurement report (e.g., if the link quality to the current serving cell falls below acceptable levels when the measurement reports are triggered in normal handover) and the failure to receive the handover command (e.g., if the link quality to the current serving cell falls below acceptable levels after the WTRU has sent the measurement report, but before it has received the HO command).

[0134] The triggering conditions for a CHO could also be based on the radio quality of the serving cells and neighbor cells like the conditions that are used in legacy NR / LTE to trigger measurement reports. For example, the WTRU could be configured with a CHO that has an A3 like triggering condition and associated HO command. The WTRU monitors the current and serving cells and when the A3 triggering conditions are fulfilled, it will, instead of sending a measurement report, execute the associated HO command and switches its connection towards the target cell. The following conditional event configurations are currently defined in NR (Rel-17): CondEvent A3, CondEvent A4, CondEvent A5, CondEvent DI, CondEvent T1. In CondEvent A3, conditional reconfiguration candidate becomes amount of offset better than PCell / PSCell. InCondEvent A4, conditional reconfiguration candidate becomes better than absolute threshold. In CondEvent A5, PCell / PSCell becomes worse than absolute thresholdl and conditional reconfiguration candidate becomes better than another absolute threshold2. In CondEvent DI, a distance between the WTRU and a reference location referenceLocationl becomes larger than configured threshold distanceThreshFromReferencel and the distance between WTRU and a reference location referenceLocation2 of conditional reconfiguration candidate becomes shorter than configured threshold distanceThreshFromReference2. In CondEvent Tl, time measured at the WTRU becomes more than configured threshold tl -Threshold but is less than tl -Threshold + duration.

[0135] It is noted that the CondEvent DI and CondEvent Tl are used in scenarios like NTN (nonterrestrial networks) where there is some location and / or time based predictability of the network conditions (e.g., it is known or can be predicted at what time a certain geographical location / area will be covered by a cell that is being served by a moving satellite).

[0136] Layer 1 (LI) / Layer 2 (L2) triggered mobility (LTM) is introduced in Rel-18 to improve handover latency. LTM can be considered as a CHO that is triggered due to a reception of a L1 / L2 indication from the network. That is, the WTRU is configured with a multitude of LTM candidate configurations (like the case of CHO), but it will execute the configuration associated with a given candidate when it receives a L1 / L2 indication (e.g., a MAC CE) from the network that indicates the candidate cell as the target cell. The network may trigger the sending of the L1 / L2 indication based on the LI measurement reports that it is getting from the UE.

[0137] The WTRU may perform early TA acquisition of a candidate cell(s) before receiving the LTM command to switch to that cell. For example, this could be done via contention-free random access (CFRA) triggered by a PDCCH order from the source cell, following which the WTRU sends preamble towards a candidate cell. The information that identifies the allocated CFRA resource can be indicated in the PDCCH order to enable shared preamble resource among multiple UEs in the RRC configuration - the source gNB dynamically indicates which WTRU uses the resource at any specific time. To minimize the data interruption of the source cell due to CFRA towards the candidate cell(s), the WTRU doesn’t receive RAR at all. That is, the target cell will indicate the delta TA to be applied to the source cell (in case both the source and the target are served by the same gNB, then this could be done internally within the gNB), and when the source sends the LTM command to the UE, it can indicate to the WTRU the del ta / ab solute TA value to apply to the target. That is, if the TA value of the candidate cell is indicated in the LTM command, the WTRU performs a RACH-less handover to the candidate cell.

[0138] Hereafter, a signal may be interchangeably referred to as or may include one or more of following: sounding reference signal (SRS), channel state information - reference signal (CSLRS), demodulation reference signal (DM-RS), phase tracking reference signal (PT-RS), synchronization signal block (SSB), etc.

[0139] Hereafter, a channel may be interchangeably referred to as or may include one or more of following: physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH), physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), physical random access channel (PRACH), etc. Hereafter, a signal, channel, and message (e.g., as in DL or UL signal, channel, and message) may be used interchangeably, while still remaining consistent with example embodiments.

[0140] Hereafter, RS may be interchangeably referred to as one or more of RS resource, RS resource set, RS port and RS port group, while still remaining consistent with example embodiments. Hereafter, RS may be interchangeably referred to as one or more of SSB, CSI-RS, SRS, and DM-RS, TRS, PRS, and PTRS, while still remaining consistent with example embodiments. Herein, time instance, slot, symbol, and subframe may be used interchangeably, while still remaining consistent with example embodiments.

[0141] Herein, the terms SSB, SS / PBCH block, PSS, SSS, PBCH, and MIB may be used interchangeably, while still remaining consistent with example embodiments. Herein, SSB, SSB beam, and SSB index may be used interchangeably, while still remaining consistent with example embodiments.

[0142] As discussed herein, the provided solutions relating to estimation and / or prediction may be used for transmissions and / or receptions belonging to a single or multiple cells as well as single or multiple TRPs, while still remaining consistent with example embodiments.

[0143] Hereafter, CSI reporting may be interchangeably referred to as or may include CSI measurement, beam reporting and / or beam measurement, while still remaining consistent with example embodiments. Hereafter, a RS resource set may be interchangeably referred to as or may include a beam group, while still remaining consistent with example embodiments.

[0144] As described herein, the terms prediction, estimation, calculation, evaluation, and determination may be used interchangeably, while still remaining consistent with example embodiments.

[0145] In RAN#94-e, RAN study item on Artificial Intelligence (AI) / Machine Learning (ML) for NR air interface was agreed. As one of the target use-cases for AI / ML for air interface, beam management was selected. This technology could be a great foundation for improving performance and complexity in conventional beam management aspects, including beam prediction in time, and / or spatial domain for overhead and latency reduction, beam selection accuracy improvement, and so forth.

[0146] In procedures corresponding to uplink (UL) timing advance (TA) detemination and application, the WTRU starts / restarts the time alignment timer (TAT) upon receiving a TA command (e.g., via RAR, MAC CE, etc.) and if the TAT timer expires, the WTRU performs several actions such as flushing all hybrid automatic repeat request (HARQ) buffers, indicating to radio resource control (RRC) to release PUCCH / SRS, clear configured downlink and / or uplink assignments and / or grants, clear PUSCH resources for semi-persistent CSI reporting, etc. That is, the MAC entity will not be able to perform any uplink transmission except RA and MSGA transmission when the TAT is not running (i.e., WTRU has to perform random access (RA) procedure to get a new TA before any UL transmission). TAT expiry may not be an issue in case the WTRU has active UL transmission (as the network will send TA adjustments and TAT is restarted), but it may occur in scenarios where the traffic is mainly / only DL.

[0147] Moreover, the RA procedure may be required due to different RA scenarios for which the RA report entry is triggered. Examples may include: random accesses associated to initial access from RRC IDLE, transition from RRC-INACTIVE and the MSG3 based SI request, beam failure recovery failure in the SpCell, WTRU executing a reconfiguration with sync, random access procedure initiated in a SpCell by DL or UL data arrival during RRC CONNECTED when the TAT is not running in the PTAG, by a PDCCH order in the serving cell, SR failures, no valid SR PUCCH resources configured, MSG1 based on demand SI request, etc. The RACH procedure may be performed via different formats for PRACH preambles, where long guard times are generally considered at the end of each RACH occasion (RO) to compensate for the effects of unknown timing advance (TA) values.

[0148] In an example, a WTRU may use a UE-sided system to determine, estimate, and / or predict the timing advance for the UL transmissions. The benefits may include any one or more of:• Avoiding UL out-of-sync. One of the most importance benefits for UE-sided TA prediction during RRC Connected-Mode is preventing, avoiding, and reducing the number of UL out- of-sync occasions.• Shorter ROs and more preambles availability. The other benefits would be the avoidance to use long ROs, resulting in increased PRACH capacity, as well as availability of a greater number of preamble indexes (e.g., Zadoff-Chu root index and cyclic shifts), resulting in less collisions and less collision handling procedures, all resulting in lower latency.• Efficient MsgA configurations. Moreover, in 2-Step RACH with predicted TA, the configurations considered for MsgA PUSCH can be different resulting in higher MCS, higher throughput PUSCH, more PUSCH occasions within a slot, etc.• TA command coverage enhancement. Furthermore, in case the WTRU predicts the TA, the follow up RRC, MAC-CE timing advance commands (TAC) will have a shorter format (as there’ll be no need for TA absolute value indication) and so the TAC coverage will be enhanced.• Enabling of RACH-less HO and CHO: If the WTRU can estimate the TA of a target cell, then a fast HO / CHO can be performed without the need for RACH.

[0149] However, the TA prediction should be accurate enough and within the CP lengths. That is, an advanced system (e.g., AIML processors) may be needed to achieve such accuracy levels. For instance, such an AIML system may be configured to provide clock drifting updates. For example, the AIML system may frequently update its clock with an external clock (e.g., GPS, GNSS, etc.) to assure availability of accurate time stamps at the UE. In particular, considering the clock drifting at the UEs, the AIML systems may require connecting to multiple satellites to compensate for such drifts. Additionally or alternatively, an AIML system may be configured to improve complexity and / or prediction for non transmitted RSs. For example, considering the proposed beam management scenarios based on CSI-RS and SSB skipping, the TA prediction for the nontransferred CSLRSs and SSBs can be (e.g., only be) accomplished by an advanced system such as AIML models.

[0150] There may be situations where a UE, which has not transmitted UL for a while, may receive indications or configurations to transmit an UL, for example, due to a soon to be expired TAT. Additionally or alternatively, a WTRU with sporadic UL traffic may occasionally determine to transmit UL based on availability of UL traffic.

[0151] The WTRU may use the previously configured TA for transmission of the determined, indicated, and / or configured UL signal and / or channel. However, the previously configured TA might not be valid anymore, due to the UE’s movements and the transmission of the configured UL may result in out-of-sync reception at the network (e.g., at the gNB) that may potentially cause interference on UL transmissions from other UEs. As such, the network (e.g., gNB) may send an order or command to the corresponding WTRU (e.g., PDCCH order) to initiate an RA to ensure UL synchronization and TA update. This may result in latency in UL transmission, as the WTRU can only send UL after all steps of RA have been accomplished and the new and updated TA is received.

[0152] Currently, the only solution is to have shorted TATs or gNB pinging the UEs to make UL transmissions more frequently that may result in waste of time and frequency resources, as well as waste of power at the UE.

[0153] According to some example embodiments described in this disclosure, solutions based on UE’s capability to determine, predict, or estimate TA are provided. That is, the WTRU that iscapable of determining, estimating, and / or predicting the TA and / or the changes in TA can inform the network (e.g., the gNB) or autonomously perform actions to reduce the abovementioned latency as well as waste of resources of time, frequency, and power. Thus, example embodiments provide methods, apparatuses and / or systems that address at least the problem of how a WTRU can handle timing-advance prediction in RRC Connected-Mode.

[0154] Some example embodiments may be directed to procedures for avoiding, preventing and / or minimizing potential UL out-of-sync by UE-sided TA prediction and mitigation. According to an embodiment, a WTRU may perform TA prediction and determine that the predicted TA may result in large TA changes (e.g., abnormal TA changes that may result in UL out-of-sync event). The WTRU may automatically mitigate the timing advance and send indications to the network or network node, such as a gNB. As a result, beneficially, the WTRU can autonomously predict the potential UL out-of-sync-event happening, may determine the delta-TA, may apply the TA changes, and may report the determined TA to the gNB. The gNB may need to know the actual TA used for each WTRU for many reasons or applications, such as positioning, power control, UEs-grouping, etc.

[0155] In an embodiment, a TA-prediction-capable WTRU may perform TA prediction based on one or more input values. According to an example, the WTRU may be configured to perform conditional TA prediction. For instance, the WTRU may determine to start performing the TA prediction based on one or more of the following: status of the TAT (e.g., only after x% of the TAT has elapsed), traffic activity level (e.g., no UL traffic for a certain configured inactivity duration), and / or mobility state change (e.g., upon detecting that it has started moving, upon detecting that its speed has increased, etc.).

[0156] An embodiment may be directed to UL-sync maintenance. For example, the WTRU may determine a value for change in the predicted TA (e.g., delta-TA) based on a difference between the predicted TA value and one or more of previously predicted TA values or gNB-configured TA values. According to one example, in case the WTRU determines that the change in the predicted TA (delta-TA) is larger than a configured threshold, the WTRU may determine or may be configured to automatically mitigate the TA by using the predicted TA for the next UL transmission. Optionally, in an embodiment, if the WTRU automatically mitigates the TA, the WTRU may restart the TAT or may start the TAT with a second (e.g., extended or increased) determined or (pre-)configured TAT value. In one example, the WTRU may report, to the gNB, one or more of: the predicted TA, the delta-TA, and / or the applied TA adjustment (e.g., via Timing Advance report (TAR) used in NTN, or as part of CSI report, PUSCH, HARQ-ACK codebook, and / or UCI PUCCH transmission).

[0157] Some example embodiments may be directed to procedures for RACH-less conditional handover (CHO) by UE-sided TA prediction. According to an embodiment, a WTRU may perform TA prediction in conjunction with cell measurements (e.g., SSB RSRP) and determine that the predicted TA for the target cell is lower than the predicted or actual TA for the serving cell. The WTRU may use this event as the condition to perform CHO. The WTRU may automatically mitigate the timing advance and may send one or more message(s) to the target cell, where the message(s) may include the predicted TA.

[0158] In an embodiment, a TA-prediction-capable WTRU may receive a CHO command from a serving cell with one or more conditions for the measured radio quality in addition to at least one condition based on actual or predicted, target-cell or serving-cell TA.

[0159] According to an embodiment, the WTRU may perform target-cell TA prediction based on measurements on one or more SSBs from the target cell. The WTRU may determine or be configured to perform target-cell TA prediction periodically, aperiodically, or semi-persistently. The WTRU with mobility may determine the target-cell TA prediction periodicity based on its speed. The WTRU may be configured to perform target-cell TA prediction based on the signal level of the serving cell or target cell (e.g., absolute signal level thresholds, relative signal level thresholds, etc.).

[0160] In an embodiment, the WTRU may be configured with a second set of radio quality (e.g., RSRP) thresholds for CHO to be used along with target-cell or serving-cell TA prediction. That is, the WTRU may use the first set of radio quality thresholds if no target-cell or serving-cell TA prediction is used and may use the second set of radio quality thresholds if target-cell or servingcell TA prediction is used. For instance, in one embodiment, the second set of CHO thresholds for RSRP may be lower than the first set.

[0161] According to an embodiment, in case the measured radio quality parameters satisfy the second set of thresholds, the WTRU may compare the predicted target-cell TA value with the predicted or actual serving-cell TA value, and may determine to perform the HO, for example, if the predicted target-cell TA is lower than the serving-cell TA, and / or if the difference between the predicted target-cell TA and serving-cell TA is higher than a threshold (e.g., to avoid ping-pong affect).

[0162] According to an embodiment, in case the WTRU performs the HO, the WTRU may determine or be configured to automatically mitigate the TA by using the predicted target-cell TA for the next UL transmission (e.g., PUSCH, e.g., including HO complete message) to the target cell. Optionally, in one embodiment, if the WTRU automatically mitigates the TA, the WTRU may restart the TAT or may start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0163] In an embodiment, the WTRU may report the predicted target-cell TA to the target cell (e.g., as part of next PUCCH or PUSCH transmission). For example, in one embodiment, the WTRU may include the determined and / or used target-cell TA in the HO complete message or a MAC- CE multiplexed with the HO complete message.

[0164] Some example embodiments may be directed to procedures for the acceptance or rejection of a predicted TA from the network (e.g., from the gNB). In an embodiment, a WTRU that has transmitted RACH based on predicted TA expects to receive short TAC via MAC-CE or RRC including only TA adjustments. This allows the network or network node, such as a gNB, to reject or confirm the predicted TA.

[0165] In an embodiment, a WTRU may be configured with a first set of resources or configurations to transmit a configured grant (CG) or SR (e.g., including a first number of maximum allowed retransmissions for SR or CGUL transmissions). According to an embodiment, a TA-prediction-capable WTRU may preform TA prediction. In an embodiment, the WTRU may send an UL transmission (e.g., via configured grant UL, SR, etc.) using the predicted TA. For example, the WTRU may report the predicted TA as part of the transmitted UL. According to an example, the WTRU may be configured with and / or may use a second set of resources or configurations to transmit the configured grant UL or SR using predicted TA.

[0166] According to an embodiment, the WTRU may monitor to receive confirmation from the gNB on the predicted TA. In case no DL message or signaling (e.g., confirmation) is received from gNB, the WTRU may retransmit the SR or the configured UL grant using the second set of resources or configurations. The WTRU may be configured with a second number of maximum allowed retransmissions for SR or configured UL based on transmitting using predicted TA. In one example, the second configured number of retransmissions may be lower than the first configured number of retransmissions.

[0167] In an embodiment, the WTRU may receive a confirmation or rejection indication via an explicit indication and / or via an implicit indication. For example, an explicit indication may be received via a new (e.g., flag) indication (e.g., via RRC, MAC-CE, or DCI) indicating if the predicted TA was accepted or rejected. The WTRU may restart the TAT or starts the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0168] For example, an implicit indication of a confirmation (e.g., accepted indication) may be via receiving a short timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). For instance, the WTRU determines that the received timing advance command (TAC) is a short TAC. That is, the TAC includes TA adjustment (e.g., negative or positive values) and not the absolute TA. The WTRU may use the received TA adjustment to update the predicted TA for determining the UL TA. The WTRU may restart the TAT or starts the TAT with a second (e.g.,extended or increased) determined or (pre)configured TAT value. As another example, an implicit indication of a rejection (e.g., predicted TA rejected) may be via receiving absolute value timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). The WTRU determines the UL TA based according to the received timing advance command (TAC) that is the absolute TA.

[0169] In an embodiment, after or upon receiving the indication (e.g., explicitly or implicitly), the WTRU may determine the TA to use for an UL transmission (e.g., predicted TA or gNB- indicated TA) based on the received confirmation / rej ection indication. For example, the WTRU may receive, from a gNB, configuration information relating to a confirmation to use the predicted TA for one or more UL transmission occasions (e.g., based on parameter of UL transmission, e.g., for URLLC, critical, or specific logical channels). For instance, the WTRU may receive the indication per configured grant or dynamic grant indication on whether the predicted TA can be used for the configured or indicated one or more UL transmission occasion(s) or not. Additionally or alternatively, for example, the WTRU may receive configuration information of second time and frequency resources to be used for transmission of configured or indicated one or more UL transmission occasions based on the predicted TA. The WTRU may use the determined UL TA for the configured or indicated one or more UL transmission occasions.

[0170] According to an embodiment, the WTRU may transmit an UL transmission in a configured or indicated one or more transmission occasions using the determined TA and may report the predicted TA and / or the determined UL TA, e.g., as part of the transmitted UL.

[0171] Some example embodiments may include procedure(s) for timing advance estimation, determination and / or prediction. In an embodiment, a WTRU may perform timing advance estimation and / or prediction. For example, a WTRU may be a TA-prediction-capable WTRU configured to perform TA prediction, e.g., based on one or more input values. As will be discussed in more detail in the following, the input value(s) may include or may be based on a time delay, a transmission time stamp of one or more signals (e.g., SSBs, RSs, etc.), SSB measurements at the serving and / or neighbor cells, and / or other means (e.g., based on a mapping table associating neighbor cell measurements and / or serving cell measurements and / or TAs, or based on an output of an AIML model or neural network).

[0172] In one example, the TA prediction may be based on time delay. For instance, there may be a scenario where a UE-sided AIML model can predict the timing advance for the detected and / or predicted SSBs or one or more reference signal (RS) resources. According to an embodiment, a UE, e.g., which may be in RRC-Connected mode, can estimate the timing advance for the received SSBs or RS signals based on AIML systems. FIG. 2A illustrates an example of timing advance prediction based on time stamps and AIML systems. For example, as illustrated inthe example of FIG. 2 A, an AIML model 205 may receive one or more of the following inputs: (i) transmission time stamp along with the received SSBs (e.g., via SIB) or reference signals, indicated for example as SSBi TS in the example of FIG. 2A; (ii) measured SSB or RSs’ channel impulse responses (CIR) that can be used to estimate the propagation delay, indicated for example as SSBi CIR in the example of FIG. 2A ; and / or (iii) reception time stamp corresponding to the received SSBs or RSs, indicated for example as SSBi Rx TS in the example of FIG. 2 A. For example, the reception time stamp may be calculated based on the GPS or GNSS time stamps that have the accuracy of 2ns.

[0173] In one example, the TA prediction may additionally or alternatively be based on the WTRU receiving transmission time stamp of one or more SSBs, RSs, etc. and using that transmission time stamp to perform TA prediction, in addition to the measured SSBs’, RSs’ CIR, the determined reception time stamp for the received SSBs, DCI, RSs, etc., configurations (e.g., TA prediction configurations), and AIML models. According to an embodiment, the WTRU may determine or be configured to perform TA prediction based on received time stamps as part of the received DCIs (e.g., DCI indicating an (e.g., aperiodic) RS transmission, DCI including PDCCH order, DCI indicating a dynamic grant, DCI indicating a TCLstate, etc.), SSB, CSI-RS, PDCCH, PDSCH, etc. In an embodiment, the WTRU may determine or be configured to perform TA prediction periodically, aperiodically, or semi-persistently or in an event-based manner.

[0174] In one example, the TA prediction may additionally or alternatively be based on SSB measurements at the serving and / or neighbor cells. FIG. 2B illustrates an example of timing advance prediction based on serving and / or neighbor cell(s) SSB measurements. For example, the network (NW) can train the AIML model 210 based on fingerprinting according to the UEs’ measurements on SSBs from the serving and neighbor cells and the corresponding measured TA values. The model can be transferred to be used at the WTRU side. The WTRU may then measure one or more parameters based on SSBs from the serving cell and neighbor cells and uses AIML model 210 to predict the TA accordingly, as shown in the example of FIG. 2B.

[0175] In one example, the TA prediction may additionally or alternatively be based on other means; for example, the WTRU could have a mapping table of neighbor cell measurements, serving cell measurements, and TAs (e.g., the mapping table may be sent to the WTRU after the network has made the fingerprinting). As another example, a neural network may be trained at the network for the sake of the WTRU and which takes serving cell and neighbor cell measurements as an input and provides the TA (of the serving cell or / and the neighbor cell as an output).

[0176] It should be noted that any of the above procedures or approaches for estimating and / or predicting the TA can be performed individually, separately or combined such that the TA estimation / prediction may be performed based on a combination of any one or more of time delay,a transmission time stamp of one or more signals (e.g., SSBs, RSs, etc.), SSB measurements at the serving and / or neighbor cells, and / or other means (e.g., based on a mapping table associating neighbor cell measurements and / or serving cell measurements and / or TAs, or based on an output of an AIML model or neural network).

[0177] In some embodiments, a timing advance may be defined based on a (cell-specific) timing advance offset (e.g., / VTA offset) and / or a (UE-specific) timing advance (e.g., ATA). The timing advance may reflect into the time for which an uplink slot / frame transmission may take place before the start of the corresponding downlink slot / frame from the serving cell. The timing advance may be determined based on (1TA+ / VTA offset) x Tc. The timing advance offset may be a cellspecific time parameter that depends on the Duplex mode and the frequency range (FR). A WTRU may receive one or more timing advance commands (TAC) from the network (e.g., from the gNB, for example, via MAC CE) for initiating, increasing, or decreasing the timing advance (e.g., ATA).

[0178] As an example, a WTRU may receive a TAC (e.g., via MAC CE) along with a randomaccess response and through an index value (e.g., TA= 0,1,2, ... ,3846) where the timing advance can be determined accordingly (e.g., ATA= TA■ 16 ■ 64 / 2 , for SCS of 2 ■ 15 kHz). In another example, a WTRU may receive a TAC (e.g., via MAC CE) to adjust the existing timing advance (e.g., NTA old) to a new value (e.g., NTA_new) through an index value (e.g., TA= 0,1,2, ... ,63), where the timing advance can be determined accordingly (e.g., NTA_new= NTA old+ (TA— 31) ■ 16 ■ 64 / 2 , for SCS of 2^ ■ 15 kHz).

[0179] In an embodiment, a WTRU may determine or be configured to perform timing advance (TA) determination, prediction, and / or estimation based on one or more measured and / or configured parameters. For example, the WTRU may perform TA prediction and / or estimation based on AIML systems, as shown in the examples of FIGs. 2A and 2B. In an example, the WTRU may perform TA prediction and / or estimation based on the time delay between the transmission time at the gNB and the reception time at the WTRU for one or more DL signals and / or channels (e.g., SSB, CSLRS, PDCCH, PDSCH, etc.). In another example, the WTRU may perform TA prediction and / or estimation for a non-serving cell based on the configured TA at the serving cell and the time difference between reception of reference signals from the serving and non-serving cells.

[0180] For example, one or more of the following procedures relating to TA determination, prediction and / or estimation may apply. The following procedures and / or parameters are nonlimiting examples of the procedures that may be included in TA determination, prediction, and / or estimation. One or more of these procedures and / or parameters may be included. However, it should be understood that other procedures and / or parameters may be included.

[0181] Some example embodiments may be directed to TA prediction and / or estimation based on time delay. For example, in an embodiment, a WTRU may determine, estimate, and / or predict the TA for UL transmission based on calculating, measuring, determining, and / or estimating the time difference between transmission time stamp of a DL (e.g., from a gNB) and the reception time stamp at the UE. For example, the WTRU may determine, estimate, and / or predict the TA using one or more of the following parameters: transmission time stamp, channel impulse responses (CIR), and / or reception time stamp.

[0182] According to an example, the WTRU may receive and / or determine the transmission time stamp of one or more reference signals and / or channels. In an example, upon detection and / or reception of an SSB, the WTRU may monitor to receive one or more system information blocks (SIBs) (e.g., SIB1, SIB2, etc.) that may include the time stamp that indicates the time at which the SSB was transmitted (e.g., from the gNB). In another example, upon reception of a PDCCH, that may for example include a DCI, the WTRU may receive the time stamp, for example as part of the DCI, that indicates the time at which the PDCCH was transmitted (e.g., from the gNB). In another example, upon reception of a PDSCH, that may for example include a MAC-CE, the WTRU may receive the time stamp, for example as part of the PDSCH or MAC-CE, that indicates the time at which the PDSCH was transmitted (e.g., from the gNB). In another example, upon reception of a reference signal (RS) (e.g., CSI-RS, PTRS, TRS, etc.) the WTRU may determine and / or receive the time stamp that is embedded as part of the sequence used in generating the reference signal. The determined time stamp may indicate the time at which the corresponding RS was transmitted (e.g., from the gNB).

[0183] According to an example, the WTRU may measure, calculate, and / or determine the CIR based on one or more DL RSs, for example to estimate the propagation delay. In an example, the WTRU may determine, be configured or receive configurations on the DL RS to be used for measuring the CIR. For example, the WTRU may receive configuration information or indications via RRC, MAC-CE, DCI, for example including PDCCH order, indicating the resources to be used for CIR measurement. In an example, the WTRU may determine, be configured, and / or indicated to use one or more SSB indexes, RS indexes, TCI states, and so forth as DL reference signals to for CIR measurement. In another example, the WTRU may determine, be configured, and / or indicated to use one or more RSs received as part of PDCCH, PDSCH, and so forth as DL reference signals to for CIR measurement. For example, one or more configured, indicated, and or received PDCCHs, PDSCHs, PBCHs, and so forth may include one or more reference signals, including for example a demodulation reference signal (DMRS).

[0184] According to an example, the WTRU may calculate and / or determine the reception time stamp for a determined, configured, and / or indicated DL signal or channel. The reception timestamp may indicate the time at which the corresponding DL signal or channel was received. In an example, the DL signals and channels may indicate one or more received SSB, CSI-RS, TRS, PTRS, TCI state, PDCCH, PDSCH, and so forth. For example, the WTRU may use Global Navigation Satellite System (GNSS), Global Positioning System (GPS), and so forth for acquiring the reception time stamp.

[0185] In an example, the WTRU may perform TA prediction and / or estimation based on AIML systems. An example AIML model is illustrated in the example of FIG. 2A, where the model provides the predicted TA as the output of the model based on the input values to the model. For example, the inputs to the model may include one or more of the following: transmission time stamp, which is shown as SSBs’ transmission (Tx) time stamp, for example, indicated as “SSBi TS” in FIG. 2A; CIR, which is shown as SSBs’ CIR, for example, indicated as “SSBi CIR’ in FIG. 2A; and / or reception time stamp, which is shown as SSBs’ reception (Rx) time stamp, for example, indicated as “SSBi Rx TS” in FIG. 2 A.

[0186] According to some example embodiments, a WTRU may determine or be configured to perform TA determination, prediction, and / or estimation based on measurements from the serving cell and non-serving cells. For example, in an embodiment, a WTRU may determine, estimate, and / or predict the timing advance for UL transmission in a cell based on calculating, measuring, determining, and / or estimating the time differences in receiving one or more reference signals from the serving and one or more non-serving cells.

[0187] In an example, the WTRU may determine the reception time for one or more first RSs (e.g., SSB) from a first cell, where for example the first cell may be UE’s serving cell. The WTRU may determine the reception time for one or more RSs (e.g., SSB) from a second cell, where for example the second cell may be a non-serving cell. The WTRU may receive indications on the time difference between transmission of the first and second RSs (e.g., SSBs) from the first and second cells, respectively. Since the WTRU is already configured with the TA to be used for UL transmission in the serving cell, the WTRU may be able to determine the TA to be used for UL transmission in the non-serving cell.

[0188] In another example, the WTRU may perform TA prediction and / or estimation based on AIML systems. An example AIML model 210 is illustrated in the example of FIG. 2B, where the model provides the predicted TA as the output of the model 210 based on the input values to the model 210. For example, the NW can train the AIML model 210 based on fingerprinting according to the UEs’ measurements on SSBs from the serving and neighbor and / or non-serving cells in addition to the corresponding measured TA values. The model 210 can be transferred to be used at the WTRU side. As such, in an example, the WTRU may measure one or more parameters based on SSBs from the serving cell (“serving cell SSB i param ” in Fig. 2B) and neighbor cells( “neighbor cell SSB i param ” in Fig. 2B) and uses the measurements as inputs to the AIML model 210 to predict the TA accordingly. In an example, the measured parameters may include RSRP, RSRQ, SINR, etc. based on the received RSs (e.g., SSB).

[0189] In another example, the WTRU may be able to determine the TA based on other means, for example, it could have a mapping table of (or representing an association between) neighbor cell measurements, serving cell measurements, and TAs. In an example, the mapping table may be sent to or configured for the WTRU after the network has made the fingerprinting. In another example, the mapping (or association between the neighbor cell measurements, serving cell measurements and TAs) may be performed based on a neural network that has been trained at the network for the sake of the WTRU that takes serving cell and neighbor cell measurements as an input and provides the TA of the serving cell and / or the neighbor cell as an output.

[0190] Some example embodiments may be directed to training and / or updating a TA prediction model. In an embodiment, a WTRU (e.g., a TA prediction-capable UE) may determine or receive an indication from the network (e.g., from a gNB) to perform TA prediction AIML model training or model update. In one example, based on the determination to perform the model training or update, the WTRU may send an indication to the network (e.g., gNB) indicating the TA prediction model training.

[0191] According to an embodiment, the WTRU may be configured, determine, or receive configuration information relating to or indicating information on a time duration / window to perform verification for the TA prediction AIML model training. For example, the WTRU may perform the verification even in RRC-IDLE-Mode, but may also perform the verification in other modes (e.g., in a connected mode). During the configured or determined time window, the WTRU may perform TA prediction, for example, based on one or more input values (e.g., received transmission time stamp of the SSBs, DCI, RSs, etc.; measured SSBs’ or RSs’ CIR; determined reception time stamp for the received SSBs, DCI, RSs, etc.), configurations (e.g., TA prediction configurations), and / or AIML models. During the time window, the WTRU may send one or more UL signals or channels (e.g, PRACH, SRS, early PRACH in LTM, PUCCH, PUSCH, etc.) to the network, e.g., a gNB, and may receive the actual TA values. In one example, the WTRU may use the difference between the actual time values and the predicted TAs for training the model. For instance, if difference is higher than a threshold, the WTRU may initiate training and / or updating the models. However, in this example, if difference is lower than the threshold, the WTRU does not initiate training procedure. The WTRU may restart the TAT or may start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value. The WTRU may report the difference and / or the decision on whether to perform training and / or updating of the TA prediction model to the network (e.g., to the gNB).

[0192] In an embodiment, a WTRU may determine, receive, or be configured with one or more configuration information and / or indications indicating the WTRU to activate and / or perform training or updating and / or fine tuning for the system (e.g., AIML model) that is used for TA prediction, estimation, calculation, and / or determination. For example, the configuration and / or indications may be based on UE’s capability. In an example, the WTRU may receive the indication and / or configuration, for example, from a gNB, via RRC, MAC-CE, DCI, etc.

[0193] For example, the WTRU that is capable of TA prediction may determine and / or receive an indication to activate the system’s model updating and / or training. In an example, the WTRU that may have installed and / or implemented or may be configured with a model capable of TA prediction, may determine or receive an indication to activate model training and / or updating. In an example, the WTRU may activate model training if the model to be used for TA prediction does not exist in UE’s memory and / or storage.

[0194] In another example, the WTRU may receive an additional indication indicating the WTRU to either perform AIML model training, fine tuning, and / or updating. For example, the WTRU may receive a flag indication where a first value (e.g., value one) may indicate a first procedure (e.g., model training activation) and a second value (e.g., value zero) may indicate a second procedure (e.g., model fine tuning and / or updating), and so forth.

[0195] In case the WTRU determines to perform TA prediction’ s model training and / or updating, the WTRU may send an indication (e.g., to a gNB). The WTRU may send the indication to indicate that the WTRU has determined to and / or may initiate model training and / or updating. The WTRU may send the indication as part of CSI reporting, PUCCH, PUSCH, and so forth, via UCI, MAC- CE, RRC, etc. The indication may include the start time and the time duration of the model training and / or updating. The indication may include UE’s determined procedure to be performed. In an example, the WTRU may send an indication (e.g., 2 -bits indication), where a first value (e.g., 00) may indicate a first selection (e.g., model training), a second value (e.g., 01) may indicate a second selection (e.g., model updating), a third value (e.g., 10) may indicate a third selection (e.g., no model updating or training is required), and so forth.

[0196] In an embodiment, a WTRU may determine, be configured, and / or receive one or more configuration information on one or more time window and / or time durations. For example, the WTRU may receive the configured time configurations as part of the received model’s training and / or updating activation indication. In an example, the time window and / or duration may be determined, configured, and / or indicated based on time instances, for example number of symbols, slots, subframes, and / or in absolute value time units (e.g., msec, usee, etc.).

[0197] Some example embodiments may include a procedure to verify and / or validate the model and / or determine if training and / or updating is required or desired. In an embodiment, a WTRUmay perform verification and / or validation of the TA prediction model within the determined and / or configured time window. The WTRU may perform the model’s validation in order to determine whether model training and / or updating is required or appropriate. In an example, the WTRU may determine or be configured to perform the validation procedure in RRC-Connected mode, in both RRC-Connected and RRC-Idle mode, or in RRC-Idle mode. According to certain embodiments, one or more of the following may occur: TA prediction, UL transmission and reception of actual measured TA value, comparing the predicted TA with measured TA values, and / or determining to perform model training or updating.

[0198] With respect to TA prediction, e.g., during the configured or determined time window, the WTRU may perform TA prediction based on one or more determined and / or configured DL RSs possibly (i.e., optionally) in addition to the other inputs to the model, such as RS’s transmission time stamp, RS’s channel impulse response, RS’s reception time, and so forth.

[0199] With respect to UL transmission and reception of actual measured TA value, for example, during the configured or determined time window, the WTRU may transmit one or more determined and / or configured UL signals and / or channels. In an example, the WTRU may be configured or receive one or more configuration information on one or more UL transmission occasions (e.g., PRACH, SRS, PUSCH, PUCCH, etc.) scheduled within the configured time window. As such, the WTRU may transmit one or more of the configured UL signals and / or channels based on the configured UL resources. Based on the UE’s UL transmission, the WTRU may receive actual measured TA values (e.g., based on network-measured TA). The WTRU may receive the absolute measured TA values or TA adjustments based on the TA used for the transmission of the determined and / or configured UL occasions. In an example, the WTRU may receive the TA adjustments or absolute value via a TAC, for example via MAC-CE, DCI, etc.

[0200] With respect to comparing the predicted TA with measured TA values, upon or after reception of the actual measured TA value, the WTRU may calculate the difference between the predicted TA and the received measured TA.

[0201] With respect to determining to perform model training or updating, if the calculated difference is higher than a first configured threshold, the WTRU may determine that the TA prediction model may require model training. If the calculated difference is lower than the first threshold but higher than a second threshold, the WTRU may determine that the TA prediction model may require model updating. If the calculated difference is lower than the second threshold, the WTRU may determine that no model training and / or updating is required. If no model updating or training is required, the WTRU may start and / or restart the TAT, where the TAT may be based on a previously determined and / or configured first TAT. Alternatively, the WTRU may be configured or determine to use a second configured and / or determined TAT, that may be longerthan the first TAT. The WTRU may receive the first and the second thresholds for the difference between the predicted and measured TA, for example via RRC, MAC-CE, DCI, etc. The WTRU may receive the first and second thresholds as part of the received activation indication and configuration.

[0202] The WTRU may determine or be configured to send an indication, for example to a gNB, indicating the UE’ s determined action for the model based on the outcome of validation procedure. The WTRU may indicate whether model training or model updating is required. The WTRU may indicate if no model training and updating is required. The WTRU may send the indication, for example via UCI, MAC-CE, RRC, etc.

[0203] Some example embidments may include procedure(s) for preventing potential UL out-of- sync by utilizing WTRU TA prediction and / or mitigation. In particular, some example embodiments may be directed to preventing or minimizing potential UL out-of-sync via WTRU- sided TA prediction and mitigation. More specifically, an embodiment may include conditional TA prediction and reporting for UL transmission. In certain embodiments, the WTRU may perform a prediction of the TA (e.g., estimating or predicting a value of the TA) and may determine that the predicted TA may result in large TA changes (e.g., abnormal TA changes that may result in UL out-of-sync event). The WTRU may then automatically mitigate the timing advance and / or send indication(s) to the network (e.g., to a gNB). Therefore, the WTRU can beneficially autonomously predict the potential UL out-of-sync-event happening, determine the delta-TA, apply the TA changes, and report the determined TA to the network (e.g., to a gNB). It is beneficial for the network to know the actual TA used for each WTRU for many possible applications, such as positioning, power control, grouping of UEs, etc.

[0204] According to an embodiment, a WTRU (e.g., a TA-prediction-capable UE) may perform TA prediction (e.g., estimating or predicting a value of a TA) based on one or more input values, as discussed elsewhere herein. For example, for conditional TA prediction, the WTRU may be configured to start performing the TA prediction depending on one or more of the following: status of the TAT (e.g., only after x% or a certain amount of the TAT has elapsed), traffic activity level (e.g., no UL traffic for a certain configured inactivity duration), and / or mobility state change (e.g., upon detecting that it has started moving, upon detecting that its speed has increased, etc.).

[0205] Alternatively or additionally, in some embodiments, the WTRU may initiate performing TA prediction if TAT has expired. That is, while TAT is running, WTRU behaves as legacy (no TA prediction). Upon TAT expiry, the WTRU may refrain from performing the legacy actions (like flushing HARQ buffers, etc.), and starts a second timer. While the second timer is running, the WTRU can perform the TA estimation and / or prediction, may operate as if the TAT has not expired (e.g., uses the TA delta value it has calculated for any UL transmission), and may triggera TA report as above based on the delta from the previous TA being greater than a threshold. If this second timer also expires and the WTRU does not receive a TA adjustment or confirmation from the network, the WTRU may fall back to legacy TAT expiry action.

[0206] In an embodiment, the WTRU may determine a value of a change in the predicted TA (e.g., delta-TA) based on a difference between the predicted TA value and one or more of previously predicted TA values or network configured (e.g., gNB -configured) TA values. For example, in case the WTRU determines that the change in the predicted TA (delta-TA) is larger than a configured threshold, the WTRU may determine or is configured to automatically mitigate the TA, e.g., by using the predicted TA for the next UL transmission. In an embodiment, optionally, if the WTRU automatically mitigates the TA, the WTRU may restart the TAT or may start the TAT with a second (e.g., extended or increased) determined or (pre-)configured TAT value. According to an embodiment, the WTRU may report one or more of: the predicted TA, the delta-TA, and / or the applied TA adjustment, to the gNB (e.g., via Timing Advance report (TAR) used in NTN, or as part of CSI report, PUSCH, HARQ-ACK codebook, and / or UCI PUCCH transmission).

[0207] In an embodiment, a WTRU may determine, be configured, or receive one or more indications and / or configuration information to start, initiate, enable, and / or activate performing timing advance estimation, determination, calculation, and / or prediction. The WTRU may determine, receive configuration information, and / or be configured to report the predicted, determined, and / or estimated TA (e.g., to a gNB). Alternatively, the WTRU may determine, be configured, or receive one or more indications and / or configuration information to stop, disable, and / or deactivate performing timing advance estimation, determination, calculation, and / or prediction. In an example, the WTRU may receive configuration information and / or indications via SIB, RRC, MAC-CE, DCI, and so forth. In another an example, the WTRU may determine to enable and / or activate the TA prediction procedure based on one or more conditions and / or events. For example, the one or more conditions or events may include or may relate to one or more received indications, the status of the TAT, the status of traffic activity, and / or the status of mobility.

[0208] In an example embodiment, a WTRU may receive configuration information and / or indications (e.g., via SIB, RRC, MAC-CE, DCI) to enable / disable TA prediction / estimation and / or to enable / disable reporting the predicted and / or estimated TA. As one example, a WTRU that is riding a high-speed train (HST) may receive an indication to disable / deactivate TA prediction and reporting. For example, a gNB may disable TA updating for all UEs in an HST and may perform the UL reception by gNB implementation and by moving the reception time’s window.

[0209] In an example embodiment, a WTRU may determine or be configured to activate and / or enable TA determination, calculation, estimation and / or prediction procedure based on a status of the TAT, e.g., based on the timer corresponding to the configured and / or determined TAT and / or in case the TAT has elapsed for a determined, indicated, and / or configured amount of time. In an example, the WTRU may receive one or more indication and / or configuration information on the TAT to be used (e.g., via RAR, MAC-CE, etc.). In another example, the WTRU may determine the TAT as part of the TA estimation and / or prediction procedure. For example, upon determination, prediction, estimation and / or reception of a first timing advance value, the WTRU may initiate, restart, and / or start a timer corresponding to the configured and / or determined TAT. In case the WTRU receives, predicts, and / or determines a second timing advance value while the timer corresponding to the TAT is running, the WTRU may initiate and / or restart the timer corresponding to the TAT. In an example, upon reception, determination, and / or prediction of the second TA, the WTRU may also receive and / or determine a new TAT, where the WTRU may restart and / or initiate the timer based on the new received and / or determined TAT value. Otherwise, in case the timer corresponding to the TAT has elapsed for a (pre)configured and / or determined time duration and the WTRU has not received an indication to restart or start the timer, the WTRU may enable and / or activate the TA prediction, estimation, calculation, and / or determination procedure. In an example, the WTRU may determine that the timer corresponding to the TAT has elapsed for a (pre)configured and / or determined percentage value of the configured, received, and / or determined TAT value. For example, the WTRU may determine that x% (or a certain amount) of the timer corresponding to the TAT has elapsed.

[0210] In an example solution, a WTRU may determine or be configured to activate and / or enable TA determination, calculation, estimation, and / or prediction procedure based on a status of the traffic activity, e.g., based on the UE’s type of traffic activity and / or amount of traffic activity. In an example, the WTRU that has not transmitted any UL traffic for a configured, indicated, and / or determined time duration, may determine and / or be configured to activate and / or enable TA prediction procedure. For example, the WTRU may determine, be (pre)configured, or receive the time duration value configuration and / or indication via SIB, RRC, MAC-CE, DCI, etc. In an example, the WTRU may determine the time duration during which the WTRU has had no UL traffic has reached a configured, indicated, and / or determined threshold. In another example, the WTRU may determine that the UE’s UL inactivity time duration has reached a configured, indicated, and / or determined threshold. As such, the WTRU may enable and / or activate TA prediction and / or reporting.

[0211] In an example embodiment, a WTRU may determine or be configured to activate and / or enable TA determination, calculation, estimation, and / or prediction procedure based on the UE’smobility status. In an example, the WTRU may determine or receive configuration information or indications (e.g., via RRC, MAC-CE, DCI, etc.) on one or more mobility states and speed thresholds, based on which the WTRU may determine to activate and / or enable TA prediction and reporting procedure. In an example, in case the WTRU detects and / or determines that the WTRU has started moving from stationary status, the WTRU may determine and / or be configured to enable TA prediction and reporting procedure. In another example, in case the WTRU detects and / or determines that the WTRU has changed its state of mobility, the WTRU may determine and / or be configured to enable TA prediction and reporting procedure. For example, the WTRU may be configured with a first state of mobility that is static and with very low speed movements (e.g., speed lower than a first threshold); the WTRU may be configured with a second state of mobility that is medium speed movements (e.g., speed higher than the first threshold and lower than a second threshold); the WTRU may be configured with a third state of mobility that is high speed movements (e.g., speed higher than the second threshold), and so forth. As such, in an example, in case the WTRU determines that UE’s mobility state has changed from the first state to the second state, from second state to the third state, and so forth, the WTRU may enable and / or activate TA prediction procedure. Alternatively, in case the WTRU determines that UE’s mobility state has changed from the second state to the first mobility state, from third mobility state to the second state, and so forth, the WTRU may determine or be configured to disable and / or deactivate the TA prediction procedure.

[0212] In an embodiment, a WTRU may determine to enable and / or activate the TA prediction procedure based on one or more of the abovementioned configurations, indications, and / or conditions. As such, the WTRU may perform the TA prediction. The WTRU may report the predicted TA, for example to a gNB. The WTRU may send the report as part of an UL transmission. In an example, the WTRU may determine the resources for the UL transmission based on a configured grant, where for example the WTRU may report the predicted TA as part of the MAC-CE, UCI, or PUSCH. In another example, the WTRU may determine the resources for the UL transmission based on one or more configured PUCCH resources. In another example, the WTRU may report the predicted TA as part of a configured and / or determined SR transmission. In another example, the WTRU may report the predicted TA as part of a configured CSI report. Alternatively, the WTRU may receive an indication (e.g., via MAC-CE, DCI, etc.) to report the predicted TA via a dynamic UL grant and / or as part of an aperiodic CSI reporting.

[0213] In an example embodiment, the WTRU may use TA that was previously configured, indicated, and / or determined for the UL transmission that is used for reporting the predicted TA. That is, as long as the TAT is not expired, the WTRU may use the TA that was configured and / or determined at the time of initiating, starting, and / or restarting the timer corresponding to the TAT.

[0214] In an example embodiment, the WTRU may determine, be configured, or receive one or more indications and / or configurations to enable or allow the WTRU to use the predicted TA for UL transmission. That is, the WTRU may use the predicted TA for transmission of the following UL transmission. In an example, the WTRU may send the report on the predicted TA as part of the transmitted UL. For example, the transmitted UL may be one of the SRS, configured grant UL, dynamic grant UL, PUCCH, PUSCH, PRACH, SR, etc.

[0215] Some embodiments may be directed to conditional TA prediction and reporting in case the TAT has expired. For example, in an embodiment, a WTRU may determine or be configured to enable and / or activate the TA prediction if a first configured, indicated, and / or determined TAT has expired for a (pre)configured and / or determined time duration. In an example, upon expiry of the first TAT, the WTRU may restart, start, and / or initiate a second timer during which the WTRU may enable and / or activate the TA prediction and / or TA reporting. In other words, the WTRU may determine or be configured to refrain from performing legacy actions for when a TAT has expired, until the second timer expires, as if the first TAT is expanded. In an example, the legacy actions for when a TAT has expired may include flushing HARQ buffers, releasing RRC PUCCH and / or SRSs, clearing configured downlink / uplink configured and / or grants, clearing PUSCH resources, etc.

[0216] In an example solution, a WTRU may determine or be configured to send an indication on the expiry of the first TAT, for example to a gNB, while the second timer is running. The report may include a report including the predicted TA. In an example, the WTRU may determine or be configured to use the previously configured and / or determined TA value for transmitting the report. In another example, the WTRU may determine or be configured to use the predicted TA for tranmsission of the indication and / or report, for example to the gNB. For example, the WTRU may transmit the indication and / or report via RRC, MAC-CE, DCI, SR, as part of CSI report, etc.

[0217] In an embodiment, the WTRU may monitor to receive a TA adjustment or a confirmation to use the predcited and / or reported TA. In case the second timer expires and the WTRU has not received a TA adjustment or a confirmation, the WTRU may fall back to the legacy TAT expiry actions.

[0218] Some example embodiments may include TA prediction and / or estimation accuracy assessment. In some example embodiments, a WTRU (e.g., a TA-prediction-capable UE) may be configured to perform TA prediction, for example, based on a detected signals and / or one or more AIML model(s). For example, the detected signals may include signals such as CSI-RS, RS, SSB, etc. In an embodiment, the WTRU may determine the validity and / or the accuracy of the predicted TA based on, for example, one or more factors. For example, the validity and / or accuracy of thepredicted TA may be based on one or more of the following: position, time stamps, mobility, and / or SIB information.

[0219] In an embodiment, the WTRU may determine the accuracy of the predicted TA based on position accuracy and / or time stamps. For example, the WTRU may receive information regarding its position in the cell (e.g., from GPS), and may determine the distance from the gNB. If the distance from gNB is lower than a configured threshold, the WTRU may determine that the accuracy of the positioning and, therefore, the accuracy of the time stamps are acceptable (e.g., as one non-limiting example to illustrate, if a WTRU is 100m away from gNB, then the WTRU can use it along with time stamp to enhance the accuracy).

[0220] In an embodiment, the WTRU may determine the accuracy of the predicted TA based on time differences. For example, the WTRU may receive the information regarding its position in the cell (e.g., from GPS), may determine the distance from the gNB, and may estimate the time difference (TA). The WTRU may receive the transmission time stamp from the gNB for the received DL signals and channels (e.g., SSB, CSI-RS, PDCCH, PDSCH, etc.), may predict the TA, and may determine the distance from the gNB accordingly. The WTRU can compare the estimated time difference and distance with the predicted time difference and distance, and may determine the accuracy of the predicted TA. As one non-limiting example, the WTRU may determine the accuracy to be valid if the difference in TA estimation and prediction are lower than the CP length.

[0221] In an embodiment, the WTRU may determine the accuracy of the predicted TA based on mobility. For example, the WTRU may determine the accuracy of the predicted TA to be valid if the state of the mobility is static or low speed. Alternatively or additionally, the WTRU may determine the periodicity to perform TA prediction based on the speed.

[0222] In an embodiment, the WTRU may determine the accuracy of the predicted TA based on SIB information. For example, the WTRU may receive high granularity time stamps from a gNB (in addition to GPS). For instance, currently SIB9 broadcasts time stamps with 1ms granularity that may be enhanced in the future to lower granularities. The WTRU can use the time stamps received from the gNB and compare them with the time stamps received from GPS and may determine if the accuracy of the received time stamp is valid.

[0223] According to some example embodiments, based on the determined validity of the TA prediction, the WTRU may determine to use the TA prediction based on AIML model or not. In case the WTRU determines to use the TA prediction, the WTRU may use a second (e.g., extended or increased) determined or (pre)configured timeAlignmentTimer value. In an embodiment, the WTRU may report the determined status to the gNB. For example, the report may include the predicted TA values.

[0224] In an embodiment, a WTRU (e.g., UE capable of performing TA prediction) may determine or be configured to validate the accuracy of the predicted TA. For example, the WTRU may determine if the accuracy of the TA prediction model is valid or invalid. In an example, the WTRU may determine the validity of the accuracy based on one or more measurements, determined, received, and / or configured thresholds, and so forth. In an example, the WTRU may receive configurations and / or indications from the network, for example from a gNB. The WTRU may determine or be configured to perform the validation of the model based on one or a combination of the following: position and / or time stamps, mobility status, and / or SIB information.

[0225] In an embodiment, the WTRU may determine the accuracy of the TA prediction based on one or more determined and / or received positioning information. In an example, the WTRU may receive, determine, and / or estimate UE’s position in the cell. For example, the WTRU may use GPS assisted location and / or position determination. In an example, the WTRU may determine, be configured, an / or receive configuration information on the location of for example the gNB. For example, the WTRU may receive the configuration information, for example via SIB, RRC, MAC-CE, and / or DCI signaling. In an example, the WTRU may determine the distance from the gNB based on UE’s determined location and / or position and the received location and / or position of the gNB.

[0226] In an embodiment, a WTRU may determine that the accuracy of the TA prediction is valid, if the distance between the WTRU and gNB is lower than a determined and / or (pre)configured threshold. For example, the WTRU may receive the threshold, for example from the gNB, for example via SIB, RRC, MAC-CE, DCI, and so forth. That is, the WTRU may determine that if the WTRU is close enough to the gNB, the determined and / or measured time stamps, time delays, propagation delays, and therefore the predicted TA is valid. For example, if the WTRU is located less than 100m away from the gNB, the WTRU may determine that the accuracy of the predicted TA is valid and, therefore, the WTRU may use the predicted TA for further configured and / or determined UL transmissions. However, if the distance between the WTRU and the gNB is longer than the determined and / or configured threshold, the WTRU may determine that the accuracy of the predicted TA may be invalid.

[0227] In an embodiment, a WTRU may estimate the timing advance based on the received, estimated, and / or determined position and / or location of the WTRU with regards to the cell. For example, the WTRU may receive and / or estimate its position and / or in the cell (e.g., by using a GPS assisted location and / or position determination, etc.). In an example, the WTRU may receive and / or determine the location of the gNB, where the WTRU may receive the information, forexample via SIB, RRC, MAC-Cem DCI, etc. The WTRU may determine the distance between WTRU and the gNB and use the determined distance to estimate the TA.

[0228] In an example embodiment, the WTRU may compare the TA that is estimated based on the distance between the WTRU and the gNB with the predicted TA. For example, the WTRU may determine that the accuracy of TA prediction is valid if the difference between the estimated TA and the predicted TA is lower than a configured and / or determined threshold. In an example, the WTRU may determine the threshold based on the CP length, for example equal to or as a function of the CP length. In another example, the WTRU may receive configuration information on the threshold, e.g., from the gNB, e.g., via RRC, MAC-CE, DCI, etc.

[0229] In an embodiment, a WTRU may determine the accuracy of TA predictions based on the mobility status of the UE. For example, the WTRU may determine the accuracy of TA prediction based on the UE’s mobility speed. In an example, the WTRU may receive one or more thresholds on the level of mobility, for example from the gNB. In an example, the WTRU may receive one or more thresholds, for example for the speed, for the number of times that the WTRU changes its direction of movement within a preconfigured time window, etc.

[0230] For example, the WTRU may be configured with a first state of mobility that is static and with very low speed movements (e.g., speed lower than a first threshold); the WTRU may be configured with a second state of mobility that is medium speed movements (e.g., speed higher than the first threshold and lower than a second threshold); the WTRU may be configured with a third state of mobility that is high speed movements (e.g., speed higher than the second threshold), and so forth.

[0231] In an example, the WTRU may determine that the accuracy of the TA prediction may be highest if the WTRU is in the first state of mobility. The WTRU may determine that the accuracy of the TA prediction may be lower if the WTRU is in the second state of mobility. The WTRU may determine that the accuracy of the predicted TA is lowest if the WTRU is in the third state of mobility, and so forth.

[0232] In an embodiment, a WTRU may determine one or more accuracy thresholds based on UE’s state of mobility. In an example, the WTRU may determine that the granularity to predict TA may be a first granularity in case the WTRU is in the first state of mobility. As such, the WTRU may determine the accuracy threshold that can be achieved if the WTRU is in the first state of mobility. In another example, the WTRU may determine the granularity to predict TA may be a second or third granularity in case the WTRU is in the second or third state of mobility, respectively. As such, the WTRU may determine the accuracy threshold that can be achieved if the WTRU is in the second or third state of mobility, accordingly.

[0233] In an example, the WTRU may report the determined accuracy threshold and / or granularity, for example to the gNB, for example via UCI, MAC-CE, RRC, etc. As such, the gNB may use the received accuracy thresholds to determine whether to enable and / or disable TA prediction at the UE, as part of the configuration information that is transmitted to the UE.

[0234] In an embodiment, a WTRU may determine the periodicity to perform measurements and / or prediction based on UE’s state of mobility. In an example, the WTRU may determine that the time period or the time duration to predict TA may be a first, a second, a third, and so forth time value in case the WTRU is in the first, second, or third state of mobility, respectively. In an example, the WTRU may report the determined time period and / or time duration, for example to the gNB, for example via UCI, MAC-CE, RRC, etc. As such, the gNB may use the received time period and / or time duration to determine whether to enable and / or disable TA prediction at the UE, as part of the configuration information that is transmitted to the UE.

[0235] In an embodiment, a WTRU may determine the accuracy of TA predictions with the support of time stamps received via SIB. In an example, the WTRU may use the time stamps received via GPS as input for the model to predict TA. The WTRU may also receive a high granularity time stamp from the gNB to determine the accuracy of the time stamps used for TA predictions. For example, the WTRU may receive a SIB dedicated for high accuracy time stamp transmission. The dedicated SIB may be transmitted periodically, aperiodically (e.g., as response to a request from the UE), or semi-persistently.

[0236] In an example, the WTRU may use the received time stamp via SIB, for example from the gNB, and compares with the time stamps received from the GPS to determines if the accuracy of the received time stamps is valid. If the time stamps received from the GPS are determined to be valid, the WTRU may determine that the TA predictions may to be valid. If the time stamps received from the GPS are determined to be invalid, the WTRU may determine that the TA predictions may be invalid.

[0237] In an embodiment, based on the determined validity of the TA prediction, a WTRU may determine to use or not to use the predicted TA. In an example, the WTRU may determine to enable or disable the TA prediction procedure. In another example, the WTRU may determine to perform model (e.g., AIML model) training and / or updating.

[0238] In an example, if the WTRU determines to use TA prediction, the WTRU may use a second determined and / or (pre)configured TAT value, where the second TAT may be extended or longer than the previously configured and / or determined first TAT.

[0239] In an example, the WTRU may report the determined status of the TA predication accuracy, for example to the gNB, for example via UCI, MAC-CE, RRC, etc. For example, the WTRU may indicate if the determined accuracy of the TA prediction is valid or invalid. The reportmay include or otherwise indicate the predicted TA value and / or other information, such as delta- TA and / or a TA adjustment applied by the UE.

[0240] In an embodiment, a WTRU may perform UL-sync maintenance, e.g., by comparing the predicted TA value for one or more of previously predicted TA values or network-configured TA values. This comparison provides a difference (e.g., delta-TA) between the predicted TA value and one or more the previously predicted or network-configured TA values. According to an embodiment, in case the WTRU determines that the change in the predicted TA (delta-TA) is larger than a configured threshold, the WTRU may determine or be configured to automatically mitigate the TA by using the predicted TA for the next UL transmission. If the WTRU automatically mitigates the TA, the WTRU may restart the TAT or may start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value. In an embodiment, the WTRU may report the predicted TA, the delta-TA, and / or the applied TA adjustment to the network (e.g., to the gNB), for example, via timing advance report (TAR) used in NTN, or as part of CSI report, PUSCH, HARQ-ACK codebook, and / or UCI PUCCH transmission).

[0241] In an embodiment, the WTRU may be configured to predict the timing advance value - herein referred to as predicted TA - based on one or more methods described herein. In an embodiment, the WTRU may be configured to perform one or more actions when a preconfigured condition is satisfied - wherein the preconfigured condition is based on predicted TA value. In an embodiment, the WTRU may be configured to monitor one or more conditions associated with predicted TA value. For example, the WTRU may perform one or more actions based on the outcome of the monitoring procedure. In some embodiments, the WTRU may perform one or more described actions if (e.g., only if) the accuracy of predicted TA is above a threshold. In one or more solutions herein, the WTRU may perform one or more described actions only if the confidence in the predicted TA is above a threshold.

[0242] In an embodiment, the WTRU may be configured with one or more parameters associated with predicted TA monitoring and / or handling. For example, the configured parameters may include a time interval k. As one example, the configured parameters may include a first threshold. As another example, the configured parameters may include a first threshold and a second threshold.

[0243] In an embodiment, the WTRU may determine a delta-TA based on predicted TA value. In an example, delta-TA may be set to be equal to predicted TA. In a solution, the delta-TA may be set to the difference between the currently applied timing advance and the predicted TA. In an embodiment, the delta-TA may be set to be equal to the difference between the most recently applied timing adjustment and the predicted TA. In an embodiment, the delta-TA may be set to be equal to the difference between previously received timing advance command from the networkand the predicted TA. In an embodiment, the delta-TA may be set to be equal to the predicted-TA * compensation factor (i.e., the predicted-TA multipled by the compensation factor), wherein the compensation factor may be preconfigured by the network. For example, the compensation factor may take a value between 0 and 1.

[0244] In an embodiment, the WTRU may determine a delta-TA based on change in predicted TA. In an example, the WTRU may determine the delta-TA value based on difference between consecutive predicted TAs. For example, the time difference between consecutive predicated TAs may be based on WTRU capability. In an embodiment, the WTRU may determine a first predicted TA value at time tl and a second predicted TA value for time t2. For example, the time difference between tl and t2 may be based on configuration from the network. For example, the time difference between tl and t2 may be based on WTRU capability. For example, the time difference between tl and t2 may be based on time interval configuration k. For example, the WTRU may determine the delta-TA based on the difference between first predicted TA at time tl and second predicted TA at t2 - is above a first threshold.

[0245] In an embodiment, the WTRU may be configured to adjust the timing advance according to the predicted TA when the delta-TA exceeds a first threshold, wherein the first threshold may be configured by the gNB or predefined. For example, the WTRU may be configured to adjust the timing advance automatically without waiting for network command.

[0246] In an embodiment, the WTRU may be configured to adjust the timing advance according to the predicted TA when the delta-TA is less than a second threshold, wherein the second threshold may be configured by the gNB or predefined. For example, the second threshold may be configured as a function of worst-case timing advance for a given deployment (e.g., cell radius). In a solution, the WTRU may be configured to adjust the timing advance according to the predicted TA only when the delta-TA exceeds the first threshold and is lower than a second threshold.

[0247] In an embodiment, the WTRU may be configured to start a timer ‘W’ when the delta-TA exceeds the first threshold. If the WTRU receives a timing adjustment from the gNB (e.g., in Timing Advance Command MAC CE or in timing advance in RAR), before the expiry of timer W, the WTRU may stop the timer W and apply the timing adjustment according to the value indicated in the timing advance command. If the timer W expires, the WTRU may apply the timing adjustment according to the predicted TA. For example, value of timer ‘W’ may be configured by the network. For example, value of timer ‘W’ may be determined by the WTRU based on the value of Time-Alignment-Timer (TAT). For example, value of timer ‘W’ may be a fractional multiple of the value of Time- Alignment-Timer (TAT).

[0248] In an embodiment, the WTRU may be configured to start or restart the TAT upon applying the timing adjustment based on the predicted TA. In an embodiment, the WTRU may beconfigured with a first TAT value and a second TAT value. The WTRU may be configured to determine the TAT duration as a function of type of timing adjustment. In an embodiment, the WTRU may be configured to (re)start the TAT with a first TAT value upon applying the timing adjustment based on received network command (e.g., in Timing Advance Command MAC CE or in timing advance in RAR). In an embodiment, the WTRU may be configured to (re)start the TAT with a second TAT value upon applying the timing adjustment based on the predicted TA. In an embodiment, the second TAT value may be expressed / configured as an increment to the first TAT value.

[0249] In an embodiment, the WTRU may be configured to transmit, to the network, an indication associated with or relating to the predicted TA and / or delta-TA. For example, in an embodiment, the WTRU may be configured to transmit, to the network, an indication when the delta-TA meets a condition. For example, the condition may be when the delta-TA exceeds or is above the first threshold. For example, the condition may be when the delta-TA is above a first threshold and below a second threshold. In an example, the first or second thresholds may be based on one or more parameters corresponding to the UL transmission occasions. For example, the first and second thresholds may be based on CP length determined based on the SCS used for the corresponding UL transmissions. As such, the first threshold may be a fraction of the CP length and the second threshold may be equal to or a multiplication of the CP length. Thus, in some embodiments, in case the WTRU detects and / or determines that the delta-TA is exceeding the first threshold, that is a fraction of the CP length, the WTRU may report an indication to report the occasion.

[0250] In an embodiment, the WTRU may transmit the indication and wait for network confirmation before applying the timing adjustment based on delta-TA. In another embodiment, the WTRU may apply the timing adjustment based on delta-TA and then indicate to the network that the timing adjustment has been applied based on predicted TA. In an embodiment, the WTRU may be configured to transmit an indication to the network when the number of timing adjustments made based on delta-TA and / or predicted-TA exceeds a threshold. In an embodiment, the WTRU may be configured to perform timing adjustments autonomously when the delta-TA exceeds a first threshold but is below a second threshold. The WTRU may be configured to indicate to the network when the delta-TA exceeds the second threshold and wait for network confirmation before applying the timing advance.

[0251] In an embodiment, the WTRU may be configured to transmit one or more of the predicted TA, the delta-TA and / or the applied TA adjustment as part of the indication to the network (e.g., to the gNB). In an embodiment, the WTRU may include information about the slots and / or subframes when the timing adjustment was applied. In an embodiment, the WTRU may includeinformation about the first UL transmission that was performed after the timing adjustment based on delta-TA and / or predicted TA was applied. In some embodiments, this indication may be referred to as indication or information associated with delta-TA and / or predicted TA.

[0252] In an embodiment, the WTRU may transmit the indication associated with delta- TA / predicted TA in a Timing Advance Report (TAR). For example, the WTRU may generate Timing Advance Report MAC CE when the UL-SCH resources are available for new transmission. If UL-SCH resources are not available, the WTRU may trigger a scheduling request. In a solution, the Timing Advance Report MAC CE may carry an indication of delta-TA and / or predicted TA. For example, the WTRU may set a first preconfigured reserved bit to be 1 to indicate that the Timing Advance included in Timing advance report MAC CE is a result of predicted TA. For example, the WTRU may set a second preconfigured reserved bit to be 1 to indicate that the WTRU has applied timing adjustment based on the Timing Advance included in Timing advance report MAC CE. In an embodiment, a new MAC CE, possibly with a preconfigured LCID, may be defined for transmission of WTRU indication associated with delta-TA and / or predicted TA.

[0253] In an embodiment, the WTRU may transmit the indication associated with delta-TA and / or predicted TA in the CSI report. For example, the WTRU may be triggered to transmit an indication associated with delta-TA and / or predicted TA. For example, the WTRU may include the indication in the CSI report, if a CSI report is triggered when an indication for delta-TA and / or predicted TA is pending. For example, the WTRU may prioritize the CSI report containing the delta-TA indication than the CSI report without the delta-TA indication. Similar solutions can be applied for the case where the indication may be multiplexed in a UCI (e.g., HARQ-ACK, SR). For example, the WTRU may be configured with HARQ-ACK codebook that includes additional delta-TA indication. In an embodiment, the WTRU may transmit the indication associated with delta-TA and / or predicted TA in a preconfigured PUCCH resource. In an embodiment, the WTRU may transmit the indication associated with delta-TA and / or predicted TA in a configured grant UL resource. In an embodiment, the WTRU may transmit the indication associated with delta-TA and / or predicted TA in a preconfigured SRS UL resource.

[0254] In an embodiment, the WTRU may transmit the indication associated with delta-TA and / or predicted TA in the RACH preamble. For example, the WTRU may be configured with dedicated preambles for the purpose of indicating that the delta-TA and / or predicted TA exceeds a threshold. For example, the WTRU may be configured with dedicated preambles for the purpose of indicating that the WTRU has applied the timing adjustment based on delta-TA and / or predicted TA. If the WTRU fails to receive a response to the preamble, the WTRU may discard the timing adjustment triggered based on delta-TA and / or predicted TA.

[0255] FIG. 3 illustrates an example flow diagram of a method for TA prediction or estimation, according to some example embodiments. For example, the method illustrated in the example of FIG. 3 may prevent or minimize potential UL out-of-sync via TA prediction and mitigation performed at the UE-side. The example method of FIG. 3 and accompanying disclosures herein may be considered a generalization or synthetization of the various embodiments discussed above. For convenience and simplicity of exposition, the example of FIG. 3 may be described with reference to the architecture or system described above with respect to FIGs. 1 A-1D and / or FIGs. 2A-2B, for instance. However, the example method depicted in FIG. 3 may be carried out using different architectures as well. According to some embodiments, the method of FIG. 3 may be implemented by a UE or WTRU, such as the WTRU 102 described in the foregoing.

[0256] It is noted that the method of FIG. 3 may include further steps, procedures or details as discussed in detail elsewhere in this disclosure. As such, the method of FIG. 3 may be modified to include any of the steps, procedures and / or details illustrated and / or discussed in the foregoing. Moreover, it is noted that the method and / or blocks of FIG. 3 may be modified to include, or to be replaced by, any one or more of the procedures or blocks discussed elsewhere herein. As such, one of ordinary skill in the art would understand that FIG. 3 is provided as one example and modifications thereto are possible while remaining within the scope of certain example embodiments.

[0257] As illustrated in the example of FIG. 3, the method may include, at 305, performing a prediction of a TA or determining a TA value. In other words, at 305, the UE or WTRU may determine, estimate or predict the value of a TA (i.e., a determined TA value or a predicted TA value). According to some example embodiments, the prediction or determination of the TA or TA value can be based on one or more input values, as discussed in detail above, including for example any one or more of: (1) a time delay, (2) a transmission time stamp of one or more signals, (3) synchronization signal block (SSB) measurements at a serving cell and / or neighbor cells, (4) a mapping table associating neighbor cell measurements, serving cell measurements and / or TAs, and / or (5) based on an output of an AIML model. In certain example embodiments, the predicting or determining of the TA value at 305 may be based on one or more detected signals (e.g., CSI- RS, RS, SSB, etc.) and / or at least one AIML model. In certain example embodiments, the UE or WTRU may determine to initiate or start performing the prediction of the TA or determination of the TA value based on one or more factors, as discussed in detail above. For example, the performing of the prediction of the TA or determining of the TA value may be initiated based on any one or more of: a status of the time alignment timer (TAT), a status of traffic activity, a status of mobility (e.g., mobility state change), and / or receiving configuration information indicating to initiate the performing of the TA prediction or determination of the TA value.

[0258] As further illustrated in the example of FIG. 3, the method may include, at 310, determining a difference between a value of the predicted or determined TA and one or more (respectively) of previously predicted or determined TA value(s) or network-configured TA value(s). In other words, a UE or WTRU can determine a value of a change in the predicted TA (i.e., delta-TA) based on the difference between the predicted or determined TA value and the one or more previously predicted or determined TA values or the network-configured (e.g., gNB -configured) TA values. As such, by determining the difference at 310, the UE or WTRU can determine that the predicted or determined TA would result in a large change in the value of the TA which may result in an UL out-of-sync event.

[0259] In the example of FIG. 3, at 315, the method may include, on condition that the difference is larger than a configured threshold, determining to use the predicted or determined TA value for a next UL transmission. Additionally, in some embodiments, on condition that the difference is larger than the configured threshold, the method may include restarting a time alignment timer (TAT) or starting the TAT with a determined or configured TAT value.

[0260] As shown in the example of FIG. 3, the method may include, at 320, sending, to the network, information associated with the predicted or determined TA value. In an embodiment, the information associated with the predicted or determined TA value may include an indication of any one or more of: the predicted or determined TA, the difference between the value of the predicted or determined TA and the one or more of previously predicted TA values or network- configured TA values, and / or a TA adjustment applied by the WTRU. In an embodiment, the information associated with the predicted or determined TA may be sent to the network via any one or more of: a timing advance report (TAR), as part of a CSI report, PUSCH, HARQ-ACK codebook, MAC-CE, and / or UCI PUCCH transmission. In an embodiment, the information associated with the predicted or determined TA may be sent in the next uplink transmission. According to some example embodiments, the next uplink transmission may include any of SRS, configured grant UL, dynamic grant UL, PUCCH, PUSCH, PRACH, and / or SR.

[0261] According to some example embodiments, the method may optionally include (although not illustrated in the example of FIG. 3) receiving, from the network, a confirmation to use the predicted or determined TA. In certain example embodiments, the method may optionally include (although not illustrated in the example of FIG. 3) receiving an indication to stop, disable or deactivate the performing of the TA prediction or determination.

[0262] It should be noted that FIG. 3 is provided as one example method, according to some embodiments. However, the method depicted in FIG. 3 may be modified according to certain embodiments, including the omission or addition of certain steps or details as may be discussed elsewhere herein.

[0263] Some example embodiments may include procedure(s) for RACH-less condition handover (CHO) by utilizing WTRU-sided TA prediction. In some example embodiments, a WTRU (e.g., a TA-prediction-capable UE) may receive a message, such as a CHO command, from a serving cell. The CHO command may include or may indicate one or more conditions for the measured radio quality, in addition to at least one condition based on the TA for the serving and target neighbor cell.

[0264] In an embodiment, the WTRU may perform TA prediction based on measurements on one or more SSBs from the target cell. For example, the WTRU may determine or be configured to perform TA prediction from the target cell periodically, aperiodically, or semi-persistently. The WTRU with mobility may determine the periodicity based on the speed. The WTRU may be configured to perform the TA prediction based on the signal level of the serving cell or target cell (e.g., absolute signal level thresholds, relative signal level thresholds, etc.).

[0265] According to an embodiment, the WTRU may be configured with a second set of radio quality (e.g., RSRP) thresholds for CHO to be used along with TA prediction. That is, the WTRU may use the first set of radio quality thresholds if no TA prediction is used and may use the second set of radio quality thresholds if TA prediction is used. For example, in certain embodiments, the second set of CHO thresholds for RSRP may be lower than the first set.

[0266] In an embodiment, in case the measured radio quality parameters satisfy the second set of thresholds, the WTRU may compare the predicted TA value of the target cell and the predicted or actual TA value of the serving cell. According to some embodiments, the WTRU may determine to perform the HO, for example, if the predicted TA of the neighbor cell is lower than the TA of the serving cell, and the difference between the predicted TA of the neighbor cell and TA of the serving cell is higher than a threshold (e.g., to avoid ping-pong affect).

[0267] According to an embodiment, in case the WTRU performs the HO, the WTRU may determine or be configured to automatically mitigate the TA by using the predicted TA for the next UL transmission (e.g., PUSCH, e.g., including HO complete message) to the target cell. In one example, if the WTRU automatically mitigates the TA, the WTRU may restart the TAT or start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0268] In an embodiment, the WTRU may report or send the predicted TA to the target cell (e.g., as part of next PUCCH or PUSCH transmission). In some examples, the WTRU may include the determined and used TA in the HO complete message or a MAC- CE multiplexed with the HO complete message.

[0269] Some example embodiments may include CHO that considers the timing advance of the serving cell. In an embodiment, the WTRU may be configured with a CHO configuration towardsa target cell that depends on TA towards the serving cell and absolute radio conditions of a neighbor cell. For example, the triggering conditions for the CHO in this case may contain the following: the TA towards the serving cell is greater than TA thresholdl, and the signal level of the neighbor cell is above a certain threshold (e.g., RSRP threshold).

[0270] In an embodiment, the WTRU may be configured with a CHO configuration towards a target cell that depends on TA towards the serving cell and relative radio conditions of a neighbor cell and the serving cell. For example, the triggering conditions for the CHO in this case may contain or indicate the following: the TA towards the serving cell is greater than TA_threshold2, and the signal level of the neighbor cell is a certain threshold above the signal level of the serving cell (e.g., RSRP threshold).

[0271] Some example embodiments may include CHO that considers the timing advance of the target cell. In an embodiment, the WTRU may be configured with a CHO configuration towards a target cell that depends on the TA towards the target cell and absolute radio conditions of the serving cell. For example, the triggering conditions for the CHO in this case may contain the following: the TA towards the target cell is less than TA thresholdl, and the signal level of the serving cell is below a certain threshold (e.g., RSRP threshold).

[0272] In an embodiment, the WTRU may be configured with a CHO configuration towards a target cell that depends on the TA towards the target cell and absolute radio conditions of the target cell. For example, the triggering conditions for the CHO in this case may contain or indicate the following: the TA towards the target cell is less than TA_threshold2, and the signal level of the target cell is above a certain threshold (e.g., RSRP threshold).

[0273] In an embodiment, the WTRU may be configured with a CHO configuration towards a target cell that depends on TA towards the target cell and relative radio conditions of the target cell and the serving cell. For example, the triggering conditions for the CHO in this case may contain or indicate the following: the TA towards the target cell is less than TA_threshold2, and the signal level of the neighbor cell is a certain threshold above the signal level of the serving cell (e.g., RSRP threshold).

[0274] Some example embodiments may include CHO that considers the timing advance of the serving and target cells. In an embodiment, the WTRU may be configured with a CHO configuration towards a target cell that depends on the TA towards the target cell and the TA towards the serving cell. For example, the triggering conditions for the CHO in this case may contain or indicate the following: the TA towards the target cell is less than TA thresholdl, and the TA towards the serving cell is greater than TA_threshold2 (e.g., RSRP threshold).

[0275] In an embodiment, the WTRU may be configured with a CHO configuration towards a target cell that depends on the relative TA towards the target cell and serving cell. For example,the triggering conditions for the CHO in this case may contain or indicate the following: the TA towards the target cell is lower than the TA towards the source cell by more than TA_threshold2.

[0276] It is noted that a combination of the above solutions or approaches can also be envisioned. For example, in certain example embodiments, the triggering condition for the CHO could be or may include the following: the TA towards the target cell is lower than the TA of the source cell by more than TA_threshold3, and the signal level of the target cell is above a certain threshold, and the signal level of the source cell is below a certain threshold.

[0277] Some example embodiments may provide or include conditions for when to start TA prediction. In an embodiment, a WTRU may be configured to predict / estimate the TA of a target / serving cell periodically (e.g., every Xms). In an embodiment, the WTRU may be configured to predict / estimate the TA of a target / serving cell upon explicit indication from the network (e.g., source gNB sending a lower layer indication, e.g., MAC CE, DCI, etc., indicating to the WTRU to perform the TA prediction for a certain neighbor cell).

[0278] In an embodiment, the WTRU may be configured to start predicting / estimating the TA of a target cell based on the signal level of the serving cell (e.g., serving cell radio signal level falls below a certain RSRP threshold).

[0279] In an embodiment, the WTRU may be configured to start predicting / estimating the TA of a target cell based on the signal level of the target cell (e.g., target cell radio signal level becomes larger than a certain RSRP threshold).

[0280] In an embodiment, the WTRU may be configured to start predicting / estimating the TA of a target cell based on the relative signal level of the target and source cell (e.g., target cell radio signal level becomes better than the source cell signal level by more than a certain RSRP threshold).

[0281] In an embodiment, the WTRU may be configured to start predicting / estimating the TA of a target cell based on the mobility state of the WTRU (e.g., UE performs the TA prediction if the mobility state of the WTRU is above or below a certain speed level).

[0282] In an embodiment, the WTRU may be configured to start predicting / estimating the TA of a target cell based on the time of stay within a given cell (e.g., UE performs the TA prediction of neighbor cells if it has stayed more than a certain time duration in the serving cell).

[0283] In an embodiment, a UE, upon the execution of the CHO, may use the determined TA of the target in sending the HO complete message, e.g., without doing RACH towards the target. In an embodiment, the WTRU may include or may indicate the TA value used (e.g., the absolute TA value, the delta TA value as compared to the last TA value that was used with the source, etc.,) in the HO complete message.

[0284] In an embodiment, the WTRU may include or may indicate the TA value used (e.g., the absolute TA value, the delta TA value as compared to the last TA value that was used with the source, etc.,) in a MAC CE that is multiplexed with the HO complete message.

[0285] In any one or more of the embodiments or examples discussed above, the WTRU may further be configured with time duration configuration associated with the TA (e.g., TA time to trigger (TTT)), and the TA conditions towards the source cell and / or target cell are fulfilled for the TA TTT duration before the WTRU considers the TA conditions are fulfilled. In one embodiment, the TA TTT is equal to the TTT used for the radio signal level (e.g., RSRP) conditions. In one embodiment, the TA TTT is greater than the TTT for the radio signal levels. In one embodiment, the TA TTT is smaller than the TTT for the radio signal levels.

[0286] In an embodiment, the TA threshold towards the serving / target cell is regarding the rate of change of the TA. For example, the CHO may be be triggered if the TA of the serving cell has changed / increased by more than a certain value / percentage within a given time duration and the neighbor cell fulfills the absolute / relative radio thresholds.

[0287] In an embodiment, the TA threshold towards the serving / target cell is regarding the change / delta from the previous TA that was used / determined for the serving / target cell (e.g., the delta value indicated in the MAC CE). For example, the CHO may be triggered if the delta TA value indicated in the TAC is greater than a certain threshold and the neighbor cell fulfills the absolute / relative radio thresholds.

[0288] In some example embodiments, the WTRU may maintain a TAT (Timing Advance Timer) for neighbor cells that it is determining / estimating the TA value for. In one example, when the WTRU has determined the TA for a given neighbor cell (or it has explicitly received the TA of the neighbor cell from the network, e.g., in something similar to the LTM MAC CE command as described above), it may refrain from determining the TA value again for that neighbor cell while the TAT for that neighbor cell is running (i.e., next TA determination is performed for that neighbor cell when the TAT for that neighbor cell expires). In an embodiment, the WTRU maintains a separate TAT for each neighbor cell. In an embodiment, the WTRU maintains a single TAT for a certain group of neighbor cells (e.g., the WTRU configured with the list of cells that are to use the same TAT). In an embodiment, the timer value for all TATs is the same, even if separate TAT is used for each neighbor cell or group of neighbor cells. In an embodiment, the timer value for the TATs of the different neighbor cells or group of neighbor cells is different. In an embodiment, the WTRU maintains only one TAT for all neighbor cells.

[0289] In an embodiment, the WTRU may maintain one TAT timer (e.g., only one TAT timer) and that is used for both serving and neighbor cells (e.g., when the TAT of the serving cell expires, WTRU performs the estimation / prediction of both serving and neighbor cells).

[0290] In an embodiment, the TAT value for the neighbor cells may be conditionally dependent on other aspects such as the radio signal level of the serving / target cell and / or the mobility state of the UE. For example, the WTRU may be configured to use short TAT values at high mobility levels, and longer TAT values at low mobility levels.

[0291] In an embodiment, the WTRU may perform a subsequent estimation / prediction of the TA of a neighbor cell upon TAT expiry only if one or more of the following are fulfilled: serving cell signal level is below a certain threshold, target cell signal level is above a certain threshold, target cell signal level is better than serving cell signal level by more than a certain threshold, and / or serving cell TA is above a certain threshold.

[0292] In an embodiment, the WTRU may be configured to apply any of the solutions above upon determining the TA to apply towards the serving cell based on the reception of a TA command from the serving cell. For example, when receiving a MAC CE TAC, the WTRU determines the absolute TA towards the serving cell (e.g., if the TAC contains the delta TA value, adding this value to the current TA value, or if the value is an absolute value, replacing the current value with the TA included in the MAC CE). If the absolute TA value is greater than the configured TA threshold, it will execute the CHO towards a neighbor cell if the radio conditions are also fulfilled (either absolute thresholds or relative thresholds, depending on the configuration). Thus, this could be considered as a legacy CHO configuration that is “activated” when the TA conditions of the serving cell are fulfilled.

[0293] In an embodiment, the WTRU may receive the TA value to apply to a target cell (absolute or relative to the source cell) from the source cell (e.g.., in a MAC CE). For example, when receiving such a MAC CE, the WTRU determines the absolute TA towards the target cell (e.g., if the TAC contains the delta TA value, absolute TA of target cell = current TA of serving cell + delta TA included in the MAC CE, , or if the value is an absolute value, or if the value is an absolute value, TA of target cell = TA included in the MAC CE) and if this absolute TA value is lower than the configured TA threshold, it will execute the CHO towards a neighbor cell if the radio conditions are also fulfilled (either absolute thresholds or relative thresholds, depending on the configuration). Thus, this could be considered as a legacy CHO configuration that is “activated” when the TA conditions of the target cell are fulfilled. It should be noted that this is different from the LTM case discussed above. In the case of the LTM, the WTRU performs a RACH-less handover to the candidate cell using the TA value provided in the LTM MAC CE, while in this case, the WTRU is just informed about the TA towards the target cell, and it will use it in determining to “activate” the CHO configuration associated with that target cell.

[0294] In an embodiment, the WTRU may be configured to apply any of the example embodiments above upon determining the TA to apply towards the source / target cell by using anAIML model. Thus, this could be considered as a legacy CHO configuration that is “activated” when the AIML model predicts a TA value to apply towards the source / target cell are above / below the configured TA threshold(s).

[0295] In an embodiment, the WTRU may start performing the measurements of neighbor cells upon (e.g., only upon) determining the TA towards the serving cell is above a certain threshold. In an embodiment, the WTRU may start performing the measurements of a certain neighbor cell upon determining the TA towards the serving cell is above a certain threshold. For example, the WTRU may be configured to start measuring cells within a certain cell group (e.g., cells of a certain frequency, cells withing a given set of cell identities, cells that belong to a certain RAT, etc.) if the TA towards the serving cell is above threshold l, and start measuring cells within another cell group if the TA towards the serving cells is above threshold_2, etc.

[0296] In an embodiment, the WTRU may not start evaluating the absolute / relative radio conditions of the neighbor cell until the TA threshold of the serving cell is fulfilled. In an embodiment, the WTRU may not start evaluating the absolute / relative radio conditions of the neighbor cell until the TA threshold of the target cell is fulfilled.

[0297] Some of the example embodiments described above might be discussed mainly in relation to CHO. However, example embodiments are not limited to CHO scenarios. For example, the example embodiments are equally applicable to the case of measurement reporting. For example, the WTRU may be configured to send a measurement report when the conditions that are related to TA of the serving and / or target cell (and radio signal level related conditions of the serving and / or target cell) are fulfilled. In one embodiment, this measurement report may include the determined TA values of the serving / target cells.

[0298] Some of the example embodiments described above might be discussed mainly in relation to HO case (i.e., the change of the PCell). However, example embodiments are equally applicable to the case of SCG change in the case of DC (E.g., CPC). For example, the WTRU may be configured to execute a CPC that changes the PSCell to a target PSCell when any of TA towards the current PSCell is above a certain TA threshold, and / or TA towards the target PSCell is below a certain TA threshold, and / or TA towards the target PSCell is lower than the TA towards the current PSCell by more than a certain TA threshold, and / or Radio signal level of the source PSCell is below a certain RSRP / RSRQ threshold, and / or Radio signal level of the target PSCell is above a certain RSRP / RSRQ threshold, and / or Radio signal level of the target PSCell is better than the signal level of the current PSCell by more than a certain RSRP / RSRQ threshold, etc.

[0299] In an embodiment, the WTRU may be configured to include the TA value of the serving cell and predicted TA values of neighbor cells in measurement reports (e.g., periodic measurement reports, event triggered measurement reports, etc.).

[0300] In an embodiment, the WTRU may be configured to log measurements of serving and / or neighbor cells when the TA value towards a serving / neighbor cell changes (e.g., based on prediction of the AIML model, based on indication of a TAC command received from the source cell regarding the TA of the serving / neighbor cell, etc.). These measurements may include the signal levels as well as the TA values of the corresponding serving and / or neighbor cells. The WTRU may indicate to the network that it has such logged measurements available (e.g., in an RRC complete message such as RRC Reconfiguration complete, WTRU information reporting message, UE assistance information messaging, etc.). The network may explicitly request the WTRU to send these logged measurements. The WTRU may also be configured to send these logged measurements based on some events (e.g., when the size of the measurements is above a certain size, e.g., x kbytes, when a certain number of such measurements have been logged, when the measurements has been logged for a certain duration, etc.). The network, for example, can use such logged measurements from a multitude of UEs to train an AIML model for TA prediction, and then transfer the model to the UEs.

[0301] In an embodiment, if the CHO conditions for more than one neighbor are fulfilled, the WTRU may prioritize the CHO towards the neighbor cell that has: the higher radio signal level, and / or the neighbor cell that has longer duration before its TAT expires (e.g., the neighbor whose TA was acquired or predicted the most recently, assuming that the TAT values are the same for all neighbors).

[0302] FIG. 4 illustrates an example flow diagram of a method for TA prediction or estimation, according to some example embodiments. For example, the method illustrated in the example of FIG. 4 may be directed to or facilitate RACH-less CHO via TA prediction at the UE. The example method of FIG. 4 and accompanying disclosures herein may be considered a generalization or synthetization of the various embodiments discussed above. For convenience and simplicity of exposition, the example of FIG. 4 may be described with reference to the architecture or system described above with respect to FIGs. 1A-1D and / or FIGs. 2A-2B, for instance. However, the example method depicted in FIG. 4 may be carried out using different architectures as well. According to some embodiments, the method of FIG. 4 may be implemented by a UE or WTRU, such as the WTRU 102 described in the foregoing.

[0303] It is noted that the method of FIG. 4 may include further steps, procedures or details as discussed in detail elsewhere in this disclosure. As such, the method of FIG. 4 may be modified to include any of the steps, procedures and / or details illustrated and / or discussed in the foregoing. Moreover, it is noted that the method and / or blocks of FIG. 4 may be modified to include, or to be replaced by, any one or more of the procedures or blocks discussed elsewhere herein. As such, one of ordinary skill in the art would understand that FIG. 4 is provided as one example andmodifications thereto are possible while remaining within the scope of certain example embodiments.

[0304] As illustrated in the example of FIG. 4, the method may include, at 405, receiving, from a serving network element, first information including or indicating a HO or conditional handover (CHO) command. In an example embodiment, the CHO command may indicate one or more conditions associated with measured radio quality and at least one condition associated with any one or more of an actual timing advance (TA) of a target network element, a predicted TA of the target network element, an actual timing advance (TA) of the serving network element, and / or a predicted TA of the serving network element.

[0305] In the example of FIG. 4, at 410, the method may include receiving second information indicating a first set of radio quality thresholds that are not to be used for a prediction of the TA of the target network element or the serving network element and a second set of radio quality thresholds for CHO that are to be used for the prediction of the TA of the target network element or the serving network element. The method may include, at 415, performing a prediction of the TA of the target network element based on measurements on one or more synchronization signal blocks (SSBs) from the target network element. In some examples, the prediction of the TA of the target network element may be performed periodically, aperiodically, and / or semi-persistently. In one example, the prediction of the TA of the target network element may be performed based on a speed of the WTRU. In one example, the prediction of the TA of the target network element may be performed based on a signal level of any of the serving network element and / or the target network element.

[0306] In the example of FIG. 4, on condition that the measured radio quality satisfies the second set of radio quality thresholds, the method may include, at 420, comparing a value of the predicted TA of the target network element with a value of the actual or the predicted TA of the serving network element. According to one example, the second set of radio quality thresholds may be lower than the first set of radio quality thresholds.

[0307] As illustrated in the example of FIG. 4, on condition that the predicted TA of the target network element is lower than the actual or the predicted TA of the serving network element and / or on condition that a difference between the predicted TA of the target network element and the actual or the predicted TA of the serving network element is higher than a threshold, the method may include, at 425, determining to perform the CHO. On condition that it is determined to perform the CHO, the method may include, at 430, determining to use the predicted TA of the target network element for a next uplink transmission to the target network element. At 435, the method may include sending, to the target network element, third information associated with the predicted TA of the target network element. According to some examples, the third informationmay be sent to the target network element in a handover complete message or a MAC- CE multiplexed with the HO complete message.

[0308] In some examples, on condition that it is determined to use the predicted TA of the target network element for a next uplink transmission, the method may include restarting a time alignment timer (TAT) or starting the TAT with a determined or configured TAT value.

[0309] It should be noted that FIG. 4 is provided as one example method, according to some embodiments. However, the method depicted in FIG. 4 may be modified according to certain embodiments, including the omission or addition of certain steps or details as may be discussed elsewhere herein.

[0310] Some example embodiments may include procedure(s) for an acceptance and / or rejection indication of a predicted TA from a network. In an embodiment, a WTRU (e.g., a TA-predicti on- capable UE) may preform TA prediction based on a detected signal(s), such as CSI-RS, RS, and / or SSB, etc., and one or more AIML model(s). The WTRU may send an UL transmission (e.g., via configured grant UL, SR, etc.) based on the predicted TA. The WTRU may report the predicted TA as part of the transmitted UL. While the WTRU is configured with a first set of resources to transmit the configured grant or the configured SR, the WTRU may be configured with a second set of resources or configurations to transmit the configured grant UL or SR based on predicted TA.

[0311] In an embodiment, the WTRU may monitor to receive confirmation from the network (e.g., from a gNB) on the predicted TA. In case no DL message or signaling (e.g., confirmation) is received from the network (gNB), the WTRU may retransmit the SR or the configured UL grant. The WTRU may be configured with a first number of allowed retransmissions for SR or configured grant UL transmission. However, the WTRU may use a second configured number of times for retransmission of SR or configured UL based on predicted TA. The second configured number of retransmissions may be lower than the first configured number of retransmissions.

[0312] According to some example embodiments, the WTRU may receive a confirmation and / or rejection indication via explicit indication or implicit indication. For example, the explicit indication may be received via a new flag indication (e.g., via RRC, MAC-CE, or DCI) indicating if the predicted TA was accepted or rejected. The WTRU may restart the TAT or start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0313] With respect to an implicit indication indicating acceptance, the acceptance (e.g., confirmation) may be received via receiving short timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). For example, the WTRU determines that the received timing advance command (TAC) is a short TAC. That is, the TAC includes TA adjustment (e.g., negative or positive values) and not the absolute TA. The WTRU uses the received TA adjustment to updatethe predicted TA for determining the UL TA. The WTRU restarts the TAT or starts the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0314] With respect to an implicit indication indicating a rejection, the rejection indication may be received via receiving absolute value timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). The WTRU determines the UL TA based according to the received timing advance command (TAC) that is the absolute TA.

[0315] Upon or after receiving the indication (e.g., acceptance or rejection), the WTRU may receive configuration information from gNB on confirmation to use the predicted TA only for specific UL transmission occasions (e.g., for URLLC, critical, or specific logical channels). The WTRU may receive the indication per configured grant or dynamic grant indication on whether the predicted TA can be used for the configured or indicated specific UL transmission occasions or not. The WTRU may receive configuration information of second time and frequency resources to be used for transmission of configured or indicated specific UL transmission occasions based on the predicted TA. The WTRU may use the determined UL TA for the configured or indicated specific UL transmission occasions.

[0316] In some example embodiments, the WTRU may be configured to report the predicted TA and / or the determined UL TA as part of the transmitted UL (e.g., as part of the UL transmission).

[0317] In an embodiment, a WTRU may receive one or more configuration information and / or indications on scheduling request (SR) resource configuration. In an example, the SR resource configurations may include one or more time and frequency resources on UL resources, for example PUCCH resources. The WTRU may use the configured and / or indicated SR resources for sending one or more SRs. For example, the WTRU may receive SR resource configurations via SIB, RRC, MAC-CE, DCI, etc.

[0318] In an example, the SR resource configurations may include one or more configuration information on the periodicity (e.g., ^PERIODICITY) intime units (e.g., symbols, slots, etc.), the time offset (e.g., ^OFFSET) intime units (e.g., in slots, e.g., by periodicityAndOffset and so forth. For example, the configurations and / or indications may indicate resources for a PUCCH transmission conveying the corresponding SR. As such, the WTRU may determine to transmit a PUCCH in the configured and / or indicated PUCCH resources based on the corresponding SR configuration.

[0319] According to an embodiment, a WTRU may receive or be configured with one or more resource allocation settings for uplink transmission (e.g., channels) in one or more Tx occasions. For example, for control uplink transmission (e.g., PUCCH), the resource configuration (e.g., for each resource allocation setting) may include one or more parameters, such as starting PRB, second hop starting PRB, number of PRBs, number of slots, starting symbol index, PUCCHformat, cyclic shift, OCC config, and so forth that may be indicated based on a PUCCH resource index / indicator (e.g., PUCCH-Resourceld).

[0320] In an example embodiment, for uplink shared channel transmission (e.g., PUSCH), the resource allocation and / or configuration may be indicated based on one or more settings and / or parameters, such as time resources (e.g., timeDomainAllocation), frequency resources (e.g., frequencyDomainAllocation), periodicity, repetition, and so forth. For example, for a PUSCH transmission corresponding to a first configured grant (e.g., Type 1) or for a PUSCH transmission corresponding to a second configured grant (e.g., Type 2) and activated (e.g., by DCI), the resource allocations are provided by one or more parameters (e.g., via ConfiguredGrantConfig in BWP- UplinkDedicated and / or activating UL grant received on the DCI).

[0321] In some example embodiments, the indication of the predicted TA may be provided via SR or configured UL grant. For example, in an embodiment, a WTRU may determine, be configured, or receive one or more configuration information and / or indications to perform TA prediction, estimation, calculation, and / or determination. The WTRU may determine or be configured to report the predicted TA as part of an UL transmission, for example to a gNB. In an example, the WTRU may use a configured UL grant (e.g., PUSCH) and / or an SR occasion (e.g., PUCCH resources used for SR transmission) for the UL transmission, in order to indicate the predicted TA.

[0322] In an embodiment, a WTRU may be configured with a first and a second set of resources for the transmission of configured UL grants, SR transmission, and so forth. The resources for the transmission of configured UL grants and / or SR transmission may include time and frequency resources, periodicity, time offsets, priority index, the number of retransmissions, TAT, and so forth. The WTRU may use the configured number of retransmissions for the limited number of times that the WTRU may retry and retransmit a configured UL transmission (e.g., configured grant, SR, etc.), in case the WTRU does not receive a corresponding DL message and / or indication, for example from the gNB. In an example, in case the WTRU reports the predicted TA and the WTRU does not receive a confirmation or a TA adjustment command, for example from the gNB, the WTRU may perform the retransmission of the corresponding UL occasion until the retransmission limit is reached. If the number of retransmissions exceeds the configured limit for the retransmissions, the WTRU may determine or be configured to initiate and / or perform a random-access procedure to connect to the cell.

[0323] In an example embodiment, the WTRU may determine and / or be configured to transmit the UL transmissions based on a previously determined and configured TA value. As such, the WTRU may use the previously configured first TAT. The WTRU may determine to use the first set of resources for the transmission of the configured grant, and / or to use the first set of resourcesfor transmission of the SR. The WTRU may use the first configured retransmission limit for the number of allowed retransmission occasions. The WTRU may use the first priority index (e.g., priority index 0) for transmission of the configured UL occasions.

[0324] In an embodiment, a WTRU may be configured, determine, or receive one or more configuration information and / or indications to transmit an UL transmission based on the predicted, estimated, calculated, and / or determined TA. As such, the WTRU may determine to use the second set of resources for the transmission of the corresponding configured grant, and / or to use the second set of resources for transmission of the corresponding SR. The WTRU may use the second configured retransmission limit for the number of allowed retransmission occasions, that may be for example lower than the first configured retransmission limit. In an example, the WTRU may use the second configured priority index for transmission of the configured UL occasions that may be higher than the first configured priority index (e.g., priority index 1).

[0325] In an example embodiment, the WTRU may determine or be configured to use a first or a second TAT values. For example, The WTRU may be configured or determine to use the previously configured first TAT. Alternatively, the WTRU may be configured or determine to use the second TAT, that may be longer than the first TAT.

[0326] According to some example embodiments, upon transmission of the UL transmission, the WTRU may monitor to receive one or more indication(s) and / or signaling, for example from a network element or a gNB, indicating whether the reported predicted TA is confirmed or rejected. In case the WTRU receives no DL signaling corresponding to confirmation or rejection of the reported TA, the WTRU may perform retransmission of the configured UL occasion and / or retransmission of the corresponding SR.

[0327] In an embodiment, a WTRU may receive one or more indications (e.g., from a gNB) for confirmation or rejection of the reported TA. For example, the WTRU may receive the confirmation as part of DL channels such as for example, PDSCH, PDCCH, etc., and RRC, MAC- CE, DCI, and so forth. The WTRU may receive a confirmation and / or rejection by explicit indication and / or implicit indication.

[0328] For explicit indication, for example, the WTRU may receive a new flag indication, for example as part of DCI, MAC-CE, RRC, etc., indicating if the predicted and reported TA is confirmed or rejected. In an example, the WTRU may determine that the predicted and / or reported TA is confirmed if a first value (e.g., value one) is received via the flag indication. In an example, the WTRU may determine that the predicted and reported TA is rejected if a second value (e.g., value zero) is received via the flag indication. In case the predicted and reported TA is confirmed, the WTRU may use the predicted TA for further UL transmissions. The WTRU may start, restart, or initiate a timer based on a previously configured first TAT. Alternatively, the WTRU may starta timer based on a second configured and / or determined TAT, where the second TAT may be for example longer than the first TAT. In case the predicted and / or reported TA is rejected, the WTRU may use the preciously indicated and / or configured TA for further UL transmissions, until a TA adjustment is received.

[0329] For implicit indication, for example, the WTRU may determine whether the reported predicted TA is confirmed or rejected based on the received timing advance command (TAC), for example via RAR, RRC, MAC-CE, DCI, etc. For an implicit confirmation, for example, the WTRU may receive the short TAC indication that includes only TA adjustments and / or zero TA adjustment indication. As such, the WTRU may determine that the predicted and / or reported TA was accepted and confirmed, for example by the gNB. In an example, the adjustment values may be positive, negative, or zero values. Upon reception of confirmation message, the WTRU may use the predicted TA in addition to possible received TA adjustment to determine the UL TA for further UL transmissions. The WTRU may start, restart, or initiate a timer based on a previously configured first TAT. Alternatively, the WTRU may start a timer based on a second configured and / or determined TAT, where the second TAT may be for example longer than the first TAT.

[0330] For an implicit rejection, for example, the WTRU may receive the long TAC indication that includes absolute value for TA configuration. As such, the WTRU may use the received TAC for determining the UL TA for further UL transmissions.

[0331] According to some example embodiments, the WTRU may determine or be configured to report the determined UL TA used for further UL transmissions.

[0332] According to some example embodiments, a WTRU may determine, be configured, or receive one or more configuration information and / or indications to use the predicted TA for (e.g., only for) one or more configured and / or indicated UL transmission occasions. For example, the WTRU may receive indications to use the TA prediction and the resulting predicted TA only for transmission of UL messages with a configured priority level, URLLC UL messages, critical UL messages, specific logical channels, etc. In an example, the WTRU may receive the indication via RAR, RRC, MAC-CE, DCI, etc. In another example, the indication may be as part of the received confirmation message.

[0333] In an example, a WTRU may receive the indication as part of the configuration information received for configuring a configured UL grant (e.g., via RRC, etc.), on whether the WTRU is enabled or disabled to use the predicted TA for the transmission of the corresponding configured UL grant. In another example, the WTRU may receive the indication as part of the configuration information received for configuring a dynamic UL grant (e.g., via MAC-CE, DCI, etc.), on whether the WTRU is enabled or disabled to use the predicted TA for the transmission of the corresponding dynamic UL grant. In another example, the WTRU may receive the indicationas part of the configuration information received for configuring each UL transmission occasion (e.g., via RRC, MAC-CE, DCI etc.), on whether the WTRU is enabled or disabled to use the predicted TA for the transmission of the corresponding UL occasion, for example for transmission of PUCCH, SRS, PRACH, SR, etc.

[0334] In an example, the WTRU may receive a second set of configurations for transmission of configured and / or indicated UL occasions based on the predicted TA. For example, the second set of configurations may include configuration information on time and frequency resources, periodicities, power control parameters, frequency hopping, etc.

[0335] FIG. 5 illustrates an example flow diagram of a method for acceptance or rejection of a predicted or estimated TA, according to some example embodiments. The example method of FIG. 5 and accompanying disclosures herein may be considered a generalization or synthetization of the various embodiments discussed above. For convenience and simplicity of exposition, the example of FIG. 5 may be described with reference to the architecture or system described above with respect to FIGs. 1A-1D and / or FIGs. 2A-2B, for instance. However, the example method depicted in FIG. 5 may be carried out using different architectures as well. According to some embodiments, the method of FIG. 5 may be implemented by a UE or WTRU, such as the WTRU 102 described in the foregoing.

[0336] It is noted that the method of FIG. 5 may include further steps, procedures or details as discussed in detail elsewhere in this disclosure. As such, the method of FIG. 5 may be modified to include any of the steps, procedures and / or details illustrated and / or discussed in the foregoing. Moreover, it is noted that the method and / or blocks of FIG. 5 may be modified to include, or to be replaced by, any one or more of the procedures or blocks discussed elsewhere herein. As such, one of ordinary skill in the art would understand that FIG. 5 is provided as one example and modifications thereto are possible while remaining within the scope of certain example embodiments.

[0337] As illustrated in the example of FIG. 5, the method may include, at 505, receiving first configuration information indicating a first set of resources to transmit a configured grant (CG) or SR. In some examples, the configuration information may further indicate (or the first set of resources may include) a first number of maximum allowed retransmissions for SR or CG UL transmissions. At 510, the method may include performing a prediction or estimation of a timing advance (TA).

[0338] In the example of FIG. 5, the method may include, at 515, transmitting a first uplink transmission (e.g., via CGUL, SR, etc.) using the predicted TA. In some examples, the first uplink transmission is sent via the CG or SR. According to an example, the predicted TA may be reported, sent or indicated as part of the first uplink transmission. According to some embodiments, the UEor WTRU may be configured with (e.g., receive configuration information) and use a second set of resources or configurations to transmit the CG UL or SR using the predicted TA. Thus, in some embodiments, the method may include receiving second configuration information indicating a second set of resources to transmit the configured grant or SR using the predicted TA.

[0339] As shown in the example of FIG. 5, the method may include, at 520, monitoring to receive (and / or receiving), from a network element, a confirmation (or indication) that the predicted TA is accepted or an indication that the predicted TA is rejected (e.g., a rejection of the predicted TA). At 525, based on the received confirmation that the predicted TA is accepted or the received indication that the predicted TA is rejected, determining, for a second uplink transmission, a TA to use from among the predicted TA or a TA indicated by the network element. In other words, the UE or WTRU can determine whether to use the predicted TA or a gNB-indicated TA for the uplink transmission, based on the received confirmation or rejection indication.

[0340] In the example of FIG. 5, the method may include, at 530, transmitting the second uplink transmission in a configured or indicated one or more transmission occasions using the determined TA. For example, any of the predicted TA and / or the determined TA are indicated as part of the second uplink transmission.

[0341] In an embodiment, on condition that no confirmation that the predicted TA is accepted and no indication that the predicted TA is rejected is received from the network element, the method may include retransmitting the configured grant or SR using the second set of resources (e.g., if no DL message or signaling (e.g., confirmation) is received from the network (e.g., gNB), the WTRU may retransmit the SR or the configured UL grant using the second set of resources or configurations).

[0342] According to an embodiment, the WTRU may be configured with, and / or may receive configuration information indicating, a second number of maximum allowed retransmissions for the configured grant or SR based on transmitting using predicted TA. The second configured number of retransmissions may be lower than a first configured number of retransmissions.

[0343] According to some example embodiments, the confirmation (that the predicted TA is accepted) or the indication (that the predicted TA is rejected) is received via an explicit indication or an implicit indication. For example, the explicit indication may be or may include a flag configured to indicate (or a value of the flag which indicates) whether the predicted TA is accepted or rejected. For instance, a first value of the flag may be used to indicate that the predicted TA is accepted and a second value of the flag may be used to indicate that the predicted TA is rejected. In one example, the WTRU may restart the TAT or start the TAT with a second (e.g., extended or increased) determined or (pre-)configured TAT value.

[0344] In some example embodiments, the implicit indication confirming that the predicted TA is accepted may be based on receiving a short timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). The UE or WTRU may determine that the received timing advance command (TAC) is a short TAC. That is, the UE or WTRU may determine that the TAC includes TA adjustment (e.g., negative or positive values) and not the absolute TA. The UE or WTRU may use the received TA adjustment to update the predicted TA for determining the UL TA. The UE or WTRU may restart the TAT or start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0345] In some example embodiments, the implicit indication indicating that the predicted TA is rejected may be based on receiving an absolute value timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). The UE or WTRU may determine the UL TA according to the received timing advance command (TAC) that is the absolute TA.

[0346] According to an embodiment, although not illustrated in the example of FIG. 5, the method may include receiving further configuration information indicating to use the predicted TA for one or more uplink transmission occasions (e.g., based on parameter of UL transmission (e.g., for URLLC, critical, or specific logical channels)). The UE or WTRU may receive the indication per configured grant or dynamic grant indication on whether the predicted TA can be used for the configured or indicated one or more UL transmission occasion(s) or not. The UE or WTRU may receive configuration information of second time and frequency resources to be used for transmission of configured or indicated one or more UL transmission occasions based on the predicted TA. The UE or WTRU may use the determined UL TA for the configured or indicated one or more UL transmission occasions.

[0347] It should be noted that FIG. 5 is provided as one example method, according to some embodiments. However, the method depicted in FIG. 5 may be modified according to certain embodiments, including the omission or addition of certain steps or details as may be discussed elsewhere herein.

[0348] An example embodiment may include a method for TA prediction or estimation, which may be performed by a UE or WTRU. The method may include performing a prediction of a TA. According to some examples, the prediction of the TA can be based on one or more input values, as discussed in detail above, including for example any one or more of (1) a time delay, (2) a transmission time stamp of one or more signals, (3) synchronization signal block (SSB) measurements at a serving cell and / or neighbor cells, (4) a mapping table associating neighbor cell measurements, serving cell measurements and / or TAs, and / or (5) based on an output of an AIML model. In some examples, the prediction of the TA may be based on one or more detected signals (e.g., CSLRS, RS, SSB, etc.) and / or at least one AIML model. In certain examples, the UE orWTRU may determine to initiate or start performing the prediction of the TA based on one or more factors including any one or more of a status of the time alignment timer (TAT), a status of traffic activity, a status of mobility (e.g., mobility state change), and / or receiving configuration information indicating to initiate the performing of the TA prediction.

[0349] The method may include determining a difference between a value of the predicted TA and one or more (respectively) of previously predicted TA value(s) or network-configured TA value(s). The method may include, on condition that the difference is larger than a configured threshold, determining to use the predicted TA for a next UL transmission. In some embodiments, on condition that the difference is larger than the configured threshold, the method may include restarting a time alignment timer (TAT) or starting the TAT with a determined or configured TAT value.

[0350] The method may include sending, to the network, information associated with the predicted TA. In an embodiment, the information associated with the predicted TA may include an indication of any one or more of the predicted TA, the difference between the value of the predicted TA and the one or more of previously predicted TA values or network-configured TA values, and / or a TA adjustment applied by the WTRU. The information associated with the predicted TA may be sent to the network via any one or more of a timing advance report (TAR), as part of a CSI report, PUSCH, HARQ-ACK codebook, MAC-CE, and / or UCI PUCCH transmission. The information associated with the predicted TA may be sent in the next uplink transmission. According to some example embodiments, the next uplink transmission comprises any of SRS, configured grant UL, dynamic grant UL, PUCCH, PUSCH, PRACH, and / or SR.

[0351] The method may optionally include receiving, from the network, a confirmation to use the predicted TA. The method may optionally include receiving an indication to stop, disable or deactivate the performing of the TA prediction.

[0352] An example embodiment may include a method for TA prediction or estimation, for example, to facilitate RACH-less CHO via TA prediction at the UE. The method may include receiving, from a serving network element, first information including or indicating a HO or conditional handover (CHO) command. In an example, the CHO command may indicate one or more conditions associated with measured radio quality and at least one condition associated with any one or more of an actual timing advance (TA) of a target network element, a predicted TA of the target network element, an actual timing advance (TA) of the serving network element, and / or a predicted TA of the serving network element.

[0353] The method may include receiving second information indicating a first set of radio quality thresholds that are not to be used for a prediction of the TA of the target network element or the serving network element and a second set of radio quality thresholds for CHO that are to beused for the prediction of the TA of the target network element or the serving network element. The method may include performing a prediction of the TA of the target network element based on measurements on one or more synchronization signal blocks (SSBs) from the target network element. In some examples, the prediction of the TA of the target network element may be performed periodically, aperiodically, and / or semi-persistently. In one example, the prediction of the TA of the target network element may be performed based on a speed of the WTRU. In one example, the prediction of the TA of the target network element may be performed based on a signal level of any of the serving network element and / or the target network element.

[0354] On condition that the measured radio quality satisfies the second set of radio quality thresholds, the method may include comparing a value of the predicted TA of the target network element with a value of the actual or the predicted TA of the serving network element. According to one example, the second set of radio quality thresholds may be lower than the first set of radio quality thresholds.

[0355] On condition that the predicted TA of the target network element is lower than the actual or the predicted TA of the serving network element and / or on condition that a difference between the predicted TA of the target network element and the actual or the predicted TA of the serving network element is higher than a threshold, the method may include determining to perform the CHO. On condition that it is determined to perform the CHO, the method may include determining to use the predicted TA of the target network element for a next uplink transmission to the target network element. The method may include sending, to the target network element, third information associated with the predicted TA of the target network element. According to some examples, the third information may be sent to the target network element in a handover complete message or a MAC- CE multiplexed with the HO complete message.

[0356] In some examples, on condition that it is determined to use the predicted TA of the target network element for a next uplink transmission, the method may include restarting a time alignment timer (TAT) or starting the TAT with a determined or configured TAT value.

[0357] An example embodiment may include a method for acceptance or rejection of a predicted or estimated TA. The method may include receiving first configuration information indicating a first set of resources to transmit a CG or SR. In some examples, the configuration information may further indicate (or the first set of resources may include) a first number of maximum allowed retransmissions for SR or CG UL transmissions. The method may include performing a prediction or estimation of a TA.

[0358] The method may include transmitting a first uplink transmission (e.g., via CG UL, SR, etc.) using the predicted TA. In some examples, the first uplink transmission is sent via the CG or SR. According to an example, the predicted TA may be reported, sent or indicated as part of thefirst uplink transmission. According to some examples, the UE or WTRU may be configured with (e.g., receive configuration information) and use a second set of resources or configurations to transmit the CG UL or SR using the predicted TA. For instance, the method may include receiving second configuration information indicating the second set of resources to transmit the configured grant or SR using the predicted TA.

[0359] The method may include monitoring to receive (and / or receiving), from a network element, a confirmation (or indication) that the predicted TA is accepted or an indication that the predicted TA is rejected (e.g., a rejection of the predicted TA). Based on the received confirmation that the predicted TA is accepted or the received indication that the predicted TA is rejected, the method may include determining, for a second uplink transmission, a TA to use from among the predicted TA or a TA indicated by the network element. In other words, the UE or WTRU can determine whether to use the predicted TA or a gNB-indicated TA for the uplink transmission, based on the received confirmation or rejection indication.

[0360] The method may include transmitting the second uplink transmission in a configured or indicated one or more transmission occasions using the determined TA, where any of the predicted TA and / or the determined TA may be indicated as part of the second uplink transmission.

[0361] In an example, on condition that no confirmation that the predicted TA is accepted and no indication that the predicted TA is rejected is received from the network element, the method may include retransmitting the configured grant or SR using the second set of resources (e.g., if no DL message or signaling (e.g., confirmation) is received from the network (e.g., gNB), the WTRU may retransmit the SR or the configured UL grant using the second set of resources or configurations).

[0362] According to an example, the WTRU may be configured with, and / or may receive configuration information indicating, a second number of maximum allowed retransmissions for the configured grant or SR based on transmitting using predicted TA. The second configured number of retransmissions may be lower than a first configured number of retransmissions.

[0363] According to some examples, the confirmation (that the predicted TA is accepted) or the indication (that the predicted TA is rejected) is received via an explicit indication or an implicit indication. For example, the explicit indication may be or may include a flag configured to indicate (or a value of the flag which indicates) whether the predicted TA is accepted or rejected. For instance, a first value of the flag may be used to indicate that the predicted TA is accepted and a second value of the flag may be used to indicate that the predicted TA is rejected. In one example, the WTRU may restart the TAT or start the TAT with a second (e.g., extended or increased) determined or (pre-)configured TAT value.

[0364] In some examples, the implicit indication confirming that the predicted TA is accepted may be based on receiving a short timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). The UE or WTRU may determine that the received timing advance command (TAC) is a short TAC. That is, the UE or WTRU may determine that the TAC includes TA adjustment (e.g., negative or positive values) and not the absolute TA. The UE or WTRU may use the received TA adjustment to update the predicted TA for determining the UL TA. The UE or WTRU may restart the TAT or start the TAT with a second (e.g., extended or increased) determined or (pre)configured TAT value.

[0365] In some examples, the implicit indication indicating that the predicted TA is rejected may be based on receiving an absolute value timing advance command (TAC) indication (e.g., via RRC, MAC-CE, or DCI). The UE or WTRU may determine the UL TA according to the received timing advance command (TAC) that is the absolute TA.

[0366] According to an example, the method may include receiving further configuration information indicating to use the predicted TA for one or more uplink transmission occasions (e.g., based on parameter of UL transmission (e.g., for URLLC, critical, or specific logical channels)). The UE or WTRU may receive the indication per configured grant or dynamic grant indication on whether the predicted TA can be used for the configured or indicated one or more UL transmission occasion(s) or not. The UE or WTRU may receive configuration information of second time and frequency resources to be used for transmission of configured or indicated one or more UL transmission occasions based on the predicted TA. The UE or WTRU may use the determined UL TA for the configured or indicated one or more UL transmission occasions.

[0367] Although features and elements are provided above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly provided as such. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods or systems.

[0368] In some example embodiments described herein, (e.g., configuration) information may be described as received by a WTRU from the network, for example, through system information or via any kind of protocol message. Although not explicitly mentioned throughout embodiments described herein, the same (e.g., configuration) information may be pre-configured in the WTRU (e.g., via any kind of pre-configuration methods such as e.g., via factory settings), such that this (e.g., configuration) information may be used by the WTRU without being received from the network.

[0369] Any characteristic, variant or embodiment described for a method is compatible with an apparatus device comprising means for processing the disclosed method, such as with a device comprising a processor configured to process the disclosed method, a computer program product comprising program code instructions and a non-transitory computer-readable storage medium storing program instructions.

[0370] The foregoing embodiments are discussed, for simplicity, with regard to the terminology and structure of infrared capable devices, i.e., infrared emitters and receivers. However, the embodiments discussed are not limited to these systems but may be applied to other systems that use other forms of electromagnetic waves or non-electromagnetic waves such as acoustic waves.

[0371] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used herein, the term "video" or the term "imagery" may mean any of a snapshot, single image and / or multiple images displayed over a time basis. As another example, when referred to herein, the terms "user equipment" and its abbreviation "UE", the term "remote" and / or the terms "head mounted display" or its abbreviation "HMD" may mean or include (i) a wireless transmit and / or receive unit (WTRU); (ii) any of a number of embodiments of a WTRU; (iii) a wireless-capable and / or wired-capable (e.g., tetherable) device configured with, inter alia, some or all structures and functionality of a WTRU; (iii) a wireless-capable and / or wired-capable device configured with less than all structures and functionality of a WTRU; or (iv) the like. Details of an example WTRU, which may be representative of any WTRU recited herein, are provided herein with respect to FIGs. 1 A-1D. As another example, various disclosed embodiments herein supra and infra are described as utilizing a head mounted display. Those skilled in the art will recognize that a device other than the head mounted display may be utilized and some or all of the disclosure and various disclosed embodiments can be modified accordingly without undue experimentation. Examples of such other device may include a drone or other device configured to stream information for providing the adapted reality experience.

[0372] In addition, the methods provided herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer- readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0373] Variations of the method, apparatus and system provided above are possible without departing from the scope of the invention. In view of the wide variety of embodiments that can be applied, it should be understood that the illustrated embodiments are examples only, and should not be taken as limiting the scope of the following claims. For instance, the embodiments provided herein include handheld devices, which may include or be utilized with any appropriate voltage source, such as a battery and the like, providing any appropriate voltage.

[0374] Moreover, in the embodiments provided above, processing platforms, computing systems, controllers, and other devices that include processors are noted. These devices may include at least one Central Processing Unit ("CPU") and memory. In accordance with the practices of persons skilled in the art of computer programming, reference to acts and symbolic representations of operations or instructions may be performed by the various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer executed" or "CPU executed."

[0375] One of ordinary skill in the art will appreciate that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. An electrical system represents data bits that can cause a resulting transformation or reduction of the electrical signals and the maintenance of data bits at memory locations in a memory system to thereby reconfigure or otherwise alter the CPU's operation, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to or representative of the data bits. It should be understood that the embodiments are not limited to the above-mentioned platforms or CPUs and that other platforms and CPUs may support the provided methods.

[0376] The data bits may also be maintained on a computer readable medium including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory (RAM)) or non-volatile (e.g., Read-Only Memory (ROM)) mass storage system readable by the CPU. The computer readable medium may include cooperating or interconnected computer readable medium, which exist exclusively on the processing system or are distributed among multiple interconnectedprocessing systems that may be local or remote to the processing system. It should be understood that the embodiments are not limited to the above-mentioned memories and that other platforms and memories may support the provided methods.

[0377] In an illustrative embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0378] There is little distinction left between hardware and software implementations of aspects of systems. The use of hardware or software is generally (but not always, in that in certain contexts the choice between hardware and software may become significant) a design choice representing cost versus efficiency tradeoffs. There may be various vehicles by which processes and / or systems and / or other technologies described herein may be effected (e.g., hardware, software, and / or firmware), and the preferred vehicle may vary with the context in which the processes and / or systems and / or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for a mainly hardware and / or firmware vehicle. If flexibility is paramount, the implementer may opt for a mainly software implementation. Alternatively, the implementer may opt for some combination of hardware, software, and / or firmware.

[0379] The foregoing detailed description has set forth various embodiments of the devices and / or processes via the use of block diagrams, flowcharts, and / or examples. Insofar as such block diagrams, flowcharts, and / or examples include one or more functions and / or operations, it will be understood by those within the art that each function and / or operation within such block diagrams, flowcharts, or examples may be implemented, individually and / or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In an embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), and / or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, may be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and / or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein may be distributed as a program productin a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a CD, a DVD, a digital tape, a computer memory, etc., and a transmission type medium such as a digital and / or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link, etc.).

[0380] Those skilled in the art will recognize that it is common within the art to describe devices and / or processes in the fashion set forth herein, and thereafter use engineering practices to integrate such described devices and / or processes into data processing systems. That is, at least a portion of the devices and / or processes described herein may be integrated into a data processing system via a reasonable amount of experimentation. Those having skill in the art will recognize that a typical data processing system may generally include one or more of a system unit housing, a video display device, a memory such as volatile and non-volatile memory, processors such as microprocessors and digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices, such as a touch pad or screen, and / or control systems including feedback loops and control motors (e.g., feedback for sensing position and / or velocity, control motors for moving and / or adjusting components and / or quantities). A typical data processing system may be implemented utilizing any suitable commercially available components, such as those typically found in data computing / communication and / or network computing / communication systems.

[0381] The herein described subject matter sometimes illustrates different components included within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality may be achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated may also be viewed as being "operably connected", or "operably coupled", to each other to achieve the desired functionality, and any two components capable of being so associated may also be viewed as being "operably couplable" to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and / or physically interacting components and / or wirelessly interactable and / or wirelessly interacting components and / or logically interacting and / or logically interactable components.

[0382] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

[0383] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, where only one item is intended, the term "single" or similar language may be used. As an aid to understanding, the following appended claims and / or the descriptions herein may include usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim including such introduced claim recitation to embodiments including only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and / or "an" should be interpreted to mean "at least one" or "one or more"). The same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of includingone of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." Further, the terms "any of' followed by a listing of a plurality of items and / or a plurality of categories of items, as used herein, are intended to include "any of," "any combination of," "any multiple of," and / or "any combination of multiples of the items and / or the categories of items, individually or in conjunction with other items and / or other categories of items. Moreover, as used herein, the term "set" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero. And the term "multiple", as used herein, is intended to be synonymous with "a plurality".

[0384] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0385] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as "up to," "at least," "greater than," "less than," and the like includes the number recited and refers to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.

[0386] Moreover, the claims should not be read as limited to the provided order or elements unless stated to that effect. In addition, use of the terms "means for" in any claim is intended to invoke 35 U.S.C. §112, 6 or means-plus-function claim format, and any claim without the terms "means for" is not so intended.

[0387] Although various embodiments have been described in terms of communication systems, it is contemplated that the systems may be implemented in software on microprocessors / general purpose computers (not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software that controls a general-purpose computer.

[0388] In addition, although some example embodiments are illustrated and described herein, the invention is not intended to just be limited to the details shown. Rather, various modifications andvariations may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit or scope invention.

[0389] ABBREVIATIONS AND ACRONYMS

[0390] Af Sub-carrier spacing

[0391] gNB NR NodeB

[0392] AP Aperiodic

[0393] BFR Beam Failure Recovery

[0394] BFD-RS Beam Failure Detection-Reference Signal

[0395] BLER Block Error Rate

[0396] BWP Bandwidth Part

[0397] CA Carrier Aggregation

[0398] CB Contention-Based (e.g. access, channel, resource)

[0399] CCA Clear Channel Assessment

[0400] CDM Code Division Multiplexing

[0401] CG Cell Group

[0402] CLI Cross-Link Interference

[0403] CoMP Coordinated Multi-Point transmission / reception

[0404] COT Channel Occupancy Time

[0405] CP Cyclic Prefix

[0406] CPE Common Phase Error

[0407] CP-OFDM Conventional OFDM (relying on cyclic prefix)

[0408] CQI Channel Quality Indicator

[0409] CN Core Network (e.g. LTE packet core or NR core)

[0410] CRC Cyclic Redundancy Check

[0411] CSI Channel State Information

[0412] CSI-RS Channel State Information-Reference Signal

[0413] CU Central Unit

[0414] D2D Device to Device transmissions (e.g. LTE Sidelink)

[0415] DC Dual Connectivity

[0416] DCI Downlink Control Information

[0417] DL Downlink

[0418] DM-RS Demodulation Reference Signal

[0419] DRB Data Radio Bearer

[0420] DU Distributed Unit

[0421] EN-DC E-UTRA - NR Dual Connectivity

[0422] EPC Evolved Packet Core

[0423] FD-CDM Frequency Domain-Code Division Multiplexing

[0424] FDD Frequency Division Duplexing

[0425] FDM Frequency Division Multiplexing

[0426] ICI Inter-Cell Interference

[0427] ICIC Inter-Cell Interference Cancellation

[0428] IP Internet Protocol

[0429] LBT Listen-Before-Talk

[0430] LCH Logical Channel

[0431] LCID Logical Channel Identity

[0432] LCP Logical Channel Prioritization

[0433] LLC Low Latency Communications

[0434] LPP LTE Positioning Protocol

[0435] LTE Long Term Evolution e.g. from 3GPP LTE R8 and up

[0436] MAC Medium Access Control

[0437] MAC CE Medium Access Control Control Element

[0438] MDT Minimization of Drive Test

[0439] NACK Negative ACK

[0440] MBMS Multimedia Broadcast Multicast System

[0441] MCG Master Cell Group

[0442] MCS Modulation and Coding Scheme

[0443] MIMO Multiple Input Multiple Output

[0444] MTC Machine-Type Communications

[0445] MR-DC Multi -RAT Dual Connectivity

[0446] NAS Non-Access Stratum

[0447] NCB-RS New candidate beam-Reference Signal

[0448] NE-DC NR-RAN - E-UTRA Dual Connectivity

[0449] NR New Radio

[0450] NR-DC Dual Connectivity with

[0451] OCC Orthogonal Cover Code

[0452] OFDM Orthogonal Frequency-Division Multiplexing

[0453] OOB Out-Of-Band (emissions)

[0454] Pcmax Total available UE power in a given transmission interval

[0455] Pcell Primary cell of Master Cell Group

[0456] PCG Primary Cell Group

[0457] PDU Protocol Data Unit

[0458] PER Packet Error Rate

[0459] PHY Physical Layer

[0460] PLMN Public Land Mobile Network

[0461] PLR Packet Loss Rate

[0462] PRACH Physical Random-Access Channel

[0463] PRB Physical Resource Block

[0464] PRI PUCCH Resource Indicator

[0465] PRS Positioning Reference Signal

[0466] Pscell Primary cell of a Secondary cell group

[0467] PSS Primary Synchronization Signal

[0468] PT-RS Phase Tracking-Reference Signal

[0469] QoS Quality of Service (from the physical layer perspective)

[0470] RAB Radio Access Bearer

[0471] RAN PA Radio Access Network Paging Area

[0472] RACH Random Access Channel (or procedure)

[0473] RAR Random Access Response

[0474] RAT Radio Access Technology

[0475] RB Resource Block

[0476] RCU Radio access network Central Unit

[0477] RF Radio Front end

[0478] RE Resource Element

[0479] RLF Radio Link Failure

[0480] RLM Radio Link Monitoring

[0481] RNTI Radio Network Identifier

[0482] RO Random Access Occasion

[0483] ROM Read-Only Mode (for MBMS)

[0484] RRC Radio Resource Control

[0485] RRM Radio Resource Management

[0486] RS Reference Signal

[0487] RSRP Reference Signal Received Power

[0488] RSRQ Reference Signal Received Quality

[0489] RTT Round-Trip Time

[0490] SBFD Subband non-overlapping full duplex

[0491] SCG Secondary Cell Group

[0492] SCMA Single Carrier Multiple Access

[0493] SCS Sub-Carrier Spacing

[0494] SI System Information

[0495] SDU Service Data Unit

[0496] SOM Spectrum Operation Mode

[0497] SP Semi-persistent

[0498] SpCell Primary cell of a master or secondary cell group.

[0499] SRB Signaling Radio Bearer

[0500] SS Synchronization Signal

[0501] SRS Sounding Reference Signal

[0502] SSS Secondary Synchronization Signal

[0503] SUL Supplementary UpLink

[0504] SWG Switching Gap (in a self-contained subframe)

[0505] TB Transport Block

[0506] TBS Transport Block Size

[0507] TCI Transmission Configuration Index

[0508] TDD Time-Division Duplexing

[0509] TDM Time-Division Multiplexing

[0510] TI Time Interval (in integer multiple of one or more symbols)

[0511] TTI Transmission Time Interval (in integer multiple of one or more symbols)

[0512] TRP Transmission / Reception Point

[0513] TRPG Transmission / Reception Point Group

[0514] TRS Tracking Reference Signal

[0515] TRx Transceiver

[0516] UL Uplink

[0517] URC Ultra-Reliable Communications

[0518] URLLC Ultra-Reliable and Low Latency Communications

[0519] V2X Vehicular communications

[0520] WLAN Wireless Local Area Networks and related technologies (IEEE 8O2.xx domain).

Claims

CLAIMSWhat is claimed is:

1. A method, implemented in a wireless transmit / receive unit (WTRU), the method comprising: determining a timing advance (TA) value based on one or more input values; determining a difference between the determined TA value and any of (1) one or more previously determined TA values and (2) network-configured TA values; on condition that the difference is larger than a configured threshold, determining to use the determined TA value for a next uplink transmission; and sending, to the network, information associated with the determined TA value.

2. The method of claim 1, wherein the determining of the TA value comprises predicting the TA value based on the one or more input values, wherein the one or more input values comprise any of: (1) a time delay, (2) a transmission time stamp of one or more signals, (3) synchronization signal block (SSB) measurements at a serving cell and / or neighbor cells, (4) a mapping table associating neighbor cell measurements, serving cell measurements and / or TAs, and (5) based on an output of an artificial intelligence / machine learning (AI / ML) model.

3. The method of at least one of claims 1-2, wherein the determining of the TA value is initiated based on any of: a status of the time alignment timer (TAT), a status of traffic activity, a status of mobility, and receiving configuration information indicating to initiate the performing of the TA prediction.

4. The method of at least one of claims 1-3, wherein the information associated with the determined TA comprises an indication of any of: (1) the determined TA, (2) the difference between the value of the determined TA value and the any of the one or more previously predicted TA values and the network-configured TA values, and (3) a TA adjustment applied by the WTRU.

5. The method of at least one of claims 1-4, wherein the information associated with the determined TA value is sent to the network via any of: a timing advance report (TAR), as part of a channel state information (CSI) report, physical uplink shared channel (PUSCH), hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook, medium access control (MAC)-control element (CE), and / or uplink control information (UCI) physical uplink control channel (PUCCH) transmission.

6. The method of at least one of claims 1-5, wherein the information associated with the determined TA value is sent in a next uplink transmission.

7. The method of claim 6, wherein the next uplink transmission comprises any of: sounding reference signal (SRS), configured uplink grant, dynamic uplink grant, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), physical random access channel (PRACH), and scheduling request (SR).

8. The method of at least one of claims 1-7, comprising, on condition that the difference is larger than the configured threshold, restarting a time alignment timer (TAT) or starting the TAT with a determined or configured TAT value.

9. The method of at least one of claims 1-8, comprising receiving an indication to stop, disable or deactivate the determining of the TA value.

10. The method of at least one of claims 1-9, comprising receiving, from the network, a confirmation to use the determined TA value.

11. The method of at least one of claims 1-10, wherein the determining of the TA value is based on one or more detected signals and an artificial intelligence / machine learning (AI / ML) model.

12. A wireless transmit / receive unit (WTRU) comprising: circuitry, including any of a processor, memory, receiver and / or transmitter, the circuitry configured to determine a timing advance (TA) value based on one or more input values; determine a difference between the determined TA value and any of (1) one or more previously determined TA values and (2) network-configured TA values; on condition that the difference is larger than a configured threshold, determine to use the determined TA value for a next uplink transmission; and send, to the network, information associated with the determined TA value.

13. The WTRU of claim 12, wherein to determine the TA value, the circuitry is configured to predict the TA value based on the one or more input values, wherein the one or more input values comprise any of: (1) a time delay, (2) a transmission time stamp of one or more signals,(3) synchronization signal block (SSB) measurements at a serving cell and / or neighbor cells, (4) a mapping table associating neighbor cell measurements, serving cell measurements and / or TAs, and (5) based on an output of an artificial intelligence / machine learning (AI / ML) model.

14. The WTRU of at least one of claims 12-13, wherein the circuitry is configured to initiate the determination of the TA value based on any of: a status of the time alignment timer (TAT), a status of traffic activity, a status of mobility, and receiving configuration information indicating to initiate the performing of the TA prediction.

15. The WTRU of at least one of claims 12-14, wherein the information associated with the determined TA comprises an indication of any of: (1) the determined TA, (2) the difference between the value of the determined TA value and the any of the one or more previously predicted TA values and the network-configured TA values, and (3) a TA adjustment applied by the WTRU.

16. The WTRU of at least one of claims 12-15, wherein the information associated with the determined TA value is sent to the network via any of: a timing advance report (TAR), as part of a channel state information (CSI) report, physical uplink shared channel (PUSCH), hybrid automatic repeat request (HARQ)-acknowledgement (ACK) codebook, medium access control (MAC)-control element (CE), and / or uplink control information (UCI) physical uplink control channel (PUCCH) transmission.

17. The WTRU of at least one of claims 12-16, wherein the information associated with the determined TA value is sent in a next uplink transmission.

18. The WTRU of claim 17, wherein the next uplink transmission comprises any of: sounding reference signal (SRS), configured uplink grant, dynamic uplink grant, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), physical random access channel (PRACH), and scheduling request (SR).

19. The WTRU of at least one of claims 12-18, the circuitry configured to, on condition that the difference is larger than the configured threshold, restart a time alignment timer (TAT) or start the TAT with a determined or configured TAT value.

20. The WTRU of at least one of claims 12-19, the circuitry configured to receive an indication to stop, disable or deactivate the determination of the TA value.

21. The WTRU of at least one of claims 12-20, the circuitry configured to receive, from the network, a confirmation to use the determined TA value.

22. The WTRU of at least one of claims 12-21, wherein the circuitry is configured to determine the TA value based on one or more detected signals and an artificial intelligence / machine learning (AI / ML) model.

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