Method and apparatus for optimization of resource utilization in mobility

Abstract

The invention relates to optimization of resource utilization in mobility in wireless communications. According to an embodiment of the present disclosure, a method performed by a user equipment (UE) configured to operate in a wireless communication system comprises: receiving, from a network, a configuration for a candidate cell for cell handover, where the configuration for the candidate cell comprises a plurality of resource configurations for the candidate cell; receiving, from the network, a cell handover command for the candidate cell, in which the cell handover command notifies a resource configuration among a plurality of resource configurations for the candidate cell; and performing a cell handover to the candidate cell based on a resource configuration notified by the cell handover command among the configurations for the candidate cell.

Description

Technical Field

[0001] The present disclosure relates to optimization of resource utilization in mobility in wireless communications. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a technology that enables high-speed packet communications. Many solutions have been proposed for LTE, including those aimed at reducing user and provider costs, improving service quality, and expanding and improving coverage and system capacity. As high-level requirements, 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of frequency bands, a simple structure, open interfaces, and appropriate power consumption of terminals.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun developing requirements and specifications for New Radio (NR) systems. 3GPP must identify and develop the technical components necessary for successful standardization of the new RAT, which will meet both immediate market needs and the longer-term requirements outlined by the ITU Radiocommunication Sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. Furthermore, NR should be able to use any spectrum band available for wireless communications in the more distant future, at least up to 100 GHz.

[0004] The goal of NR is to be a single technology framework that addresses all use cases, requirements, and deployment scenarios, including enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), ultra-reliable and low-latency communications (URLLC), etc. NR should be inherently forward-compatible.

[0005] In wireless communications, a user equipment (UE) can perform mobility from a source cell to a target cell with better quality than the source cell. During mobility, the network may have to reserve resources for multiple UEs. However, this resource reservation can lead to inefficient resource utilization and, in some cases, resource shortages. Summary of the Invention

[0006] Solution to the problem

[0007] One aspect of the present disclosure is to provide a method and apparatus for optimizing resource utilization in mobility in a wireless communication system.

[0008] According to an embodiment of the present disclosure, a method performed by a user equipment (UE) configured to operate in a wireless communication system includes: receiving a configuration for a candidate cell for cell switching from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell switching command for the candidate cell from the network, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell; and performing cell switching to the candidate cell based on the resource configuration notified by the cell switching command in the configuration for the candidate cell.

[0009] According to an embodiment of the present disclosure, a user equipment (UE) configured to operate in a wireless communication system includes: at least one transceiver; at least one processor; and at least one memory, which is operatively connected to the at least one processor and stores instructions, wherein the instructions perform operations based on being executed by the at least one processor, and the operations include: receiving a configuration for a candidate cell for cell switching from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell switching command for the candidate cell from the network, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell; and performing cell switching to the candidate cell based on the resource configuration in the configuration for the candidate cell notified by the cell switching command.

[0010] According to an embodiment of the present disclosure, a network node configured to operate in a wireless communication system includes: at least one transceiver; at least one processor; and at least one memory, which is operatively connected to the at least one processor and stores instructions, wherein the instructions perform operations based on being executed by the at least one processor, the operations including: sending a configuration for a candidate cell for cell switching to a user equipment (UE), wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; and sending a cell switching command for the candidate cell to the UE, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell, wherein the cell switching to the candidate cell is performed based on the resource configuration notified by the cell switching command in the configuration for the candidate cell.

[0011] According to an embodiment of the present disclosure, a method performed by a network node configured to operate in a wireless communication system includes: sending a configuration for a candidate cell for cell switching to a user equipment (UE), wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; and sending a cell switching command for the candidate cell to the UE, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell, wherein the cell switching to the candidate cell is performed based on the resource configuration notified by the cell switching command in the configuration for the candidate cell.

[0012] According to an embodiment of the present disclosure, a device suitable for operating in a wireless communication system includes: at least one processor; and at least one memory, which is operatively connected to the at least one processor and stores instructions, wherein the instructions perform operations based on being executed by the at least one processor, and the operations include: receiving a configuration for a candidate cell for cell switching from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell switching command for the candidate cell from the network, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell; and performing cell switching to the candidate cell based on the resource configuration in the configuration for the candidate cell notified by the cell switching command.

[0013] According to an embodiment of the present disclosure, a non-transitory computer-readable medium (CRM) stores program code for implementing instructions, wherein the instructions perform operations based on being executed by at least one processor, the operations including: receiving a configuration for a candidate cell for cell switching from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell switching command for the candidate cell from the network, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell; and performing a cell switching to the candidate cell based on the resource configuration in the configuration for the candidate cell notified by the cell switching command.

[0014] The present disclosure may have various advantageous effects.

[0015] For example, according to the present disclosure, a network (NW) may pre-configure one or more physical channel configurations for a bandwidth part (BWP) of a candidate cell to a UE. When the NW determines that the UE performs LTM execution to the candidate cell, the candidate cell may reserve a physical channel configuration for the UE from among the pre-configured physical channel configurations in the first BWP. The NW may then send an LTM command to the UE, indicating that the candidate cell is reserving the physical channel configuration for LTM execution. Upon receiving the LTM command from the NW, the UE may perform LTM to the candidate cell, that is, the UE may apply the pre-configured configuration indicated by the LTM command.

[0016] To this end, the network can prevent resource shortage problems by dynamically allocating physical resources for UE use at the time of LTM execution. As a result, the efficiency of network resource utilization can be improved.

[0017] The beneficial effects that can be obtained by the specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, there may be various technical effects that can be understood and / or derived from the present disclosure by a person of ordinary skill in the relevant art. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 An example of a communication system to which an implementation of the present disclosure is applied is shown.

[0019] Figure 2 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0020] Figure 3 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0021] Figure 4 and Figure 5 An example of a protocol stack in a 3GPP-based wireless communication system to which implementations of the present disclosure are applied is shown.

[0022] Figure 6 The frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied is shown.

[0023] Figure 7 An example of data flow in a 3GPP NR system to which an implementation of the present disclosure is applied is shown.

[0024] Figure 8 An example of a traditional handover process to which the technical features of the present disclosure can be applied is shown.

[0025] Figure 9 An example of a conditional handover process to which the technical features of the present disclosure can be applied is shown.

[0026] Figure 10 An example of a signaling procedure for an LTM according to an embodiment of the present disclosure is shown.

[0027] Figure 11 An example of a method performed by a UE according to an embodiment of the present disclosure is shown.

[0028] Figure 12 An example of a signal flow between a UE and a network node according to an embodiment of the present disclosure is shown.

[0029] Figure 13 An example of a method of indicating a physical channel configuration in an LTM according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0030] The following techniques, devices, and systems can be applied to various wireless multiple access systems. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented using radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented using radio technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) that uses E-UTRA. 3GPP LTE uses OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). Evolutions of 3GPP LTE include LTE-Advanced (LTE-A), LTE-A Pro, and / or 5G New Radio (NR).

[0031] For ease of description, the implementation of the present disclosure is primarily described with respect to a 3GPP-based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP-based wireless communication system, various aspects of the present disclosure that are not limited to a 3GPP-based wireless communication system are applicable to other mobile communication systems.

[0032] For terms and techniques not specifically described among the terms and techniques employed in the present disclosure, reference may be made to wireless communication standard documents published prior to the present disclosure.

[0033] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, in the present disclosure, "A or B" may be interpreted as "A and / or B". For example, in the present disclosure, "A, B, or C" may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0034] In the present disclosure, a slash ( / ) or a comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0035] In the present disclosure, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, the expression “at least one of A or B” or “at least one of A and / or B” in the present disclosure may be interpreted as being the same as “at least one of A and B”.

[0036] In addition, in the present disclosure, “at least one of A, B, and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.” In addition, “at least one of A, B, or C” or “at least one of A, B, and / or C” may mean “at least one of A, B, and C.”

[0037] In addition, the brackets used in this disclosure may mean "for example". Specifically, when "control information (PDCCH)" is shown, "PDCCH" can be cited as an example of "control information". In other words, in this disclosure, "control information" is not limited to "PDCCH", and "PDCCH" can be cited as an example of "control information". In addition, even when "control information (i.e., PDCCH)" is shown, "PDCCH" can be cited as an example of "control information".

[0038] The technical features described separately in one figure in this disclosure can be implemented separately or simultaneously.

[0039] Although not limited thereto, the various descriptions, functions, processes, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein may be applied to various fields requiring wireless communication and / or connectivity (e.g., 5G) between devices.

[0040] Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings. Unless otherwise specified, the same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks and / or functional blocks.

[0041] Figure 1 An example of a communication system to which an implementation of the present disclosure is applied is shown.

[0042] Figure 1 The 5G usage scenarios shown are only exemplary, and the technical features of the present disclosure can be applied to Figure 1 Other 5G usage scenarios not shown.

[0043] The three main demand categories for 5G include: (1) enhanced mobile broadband (eMBB) category, (2) massive machine type communication (mMTC) category, and (3) ultra-reliable and low-latency communication (URLLC) category.

[0044] Reference Figure 1 , the communication system 1 includes wireless devices 100a to 100f, a base station (BS) 200, and a network 300. Figure 1 A 5G network is illustrated as an example of the network of the communication system 1 , but implementations of the present disclosure are not limited to the 5G system and may be applied to future communication systems other than the 5G system.

[0045] BS 200 and network 300 may be implemented as wireless devices, and certain wireless devices may operate as BSs / network nodes relative to other wireless devices.

[0046] Wireless devices 100a to 100f represent devices that perform communication using a radio access technology (RAT) (e.g., 5G NR or LTE) and may be referred to as communication / radio / 5G devices. Wireless devices 100a to 100f may include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with wireless communication capabilities, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. A vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, and the like. Handheld devices can include smartphones, smart tablets, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances can include TVs, refrigerators, and washing machines. IoT devices can include sensors and smart meters.

[0047] In the present disclosure, wireless devices 100a to 100f may be referred to as user equipment (UE). UE may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a tablet-shaped personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle with autonomous driving capabilities, a connected car, an unmanned aerial vehicle (UAV), an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a FinTech device (or financial device), a security device, a weather / environmental device, a device related to 5G services, or a device related to the Fourth Industrial Revolution.

[0048] Wireless devices 100a to 100f can connect to network 300 via BS 200. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 400 via network 300. Network 300 can be configured using a 3G network, a 4G network (e.g., LTE), a 5G network (e.g., NR), and a beyond 5G network. While wireless devices 100a to 100f can communicate with each other via BS 200 / network 300, wireless devices 100a to 100f can perform direct communication with each other (e.g., sidelink communication) without going through BS 200 / network 300. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0049] Wireless communications / connections 150a, 150b, and 150c may be established between wireless devices 100a to 100f and / or between wireless devices 100a to 100f and BS 200 and / or between BS 200. Wireless communications / connections may be established via various RATs (e.g., 5G NR), such as uplink / downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, and inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)). Wireless devices 100a to 100f and BS 200 / wireless devices 100a to 100f may transmit / receive radio signals to / from each other via wireless communications / connections 150a, 150b, and 150c. For example, wireless communications / connections 150a, 150b, and 150c may transmit / receive signals via various physical channels. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of the resource allocation process can be performed based on the various proposals of the present disclosure.

[0050] NR supports multiple numerologies (and / or multiple subcarrier spacings (SCS)) to support various 5G services. For example, if the SCS is 15kHz, wide areas can be supported in traditional cellular bands, while if the SCS is 30kHz / 60kHz, dense cities, lower latency, and wider carrier bandwidths can be supported. If the SCS is 60kHz or higher, bandwidths greater than 24.25GHz can be supported to overcome phase noise.

[0051] The NR frequency band can be defined as two types of frequency ranges, namely, frequency range 1 (FR1) and frequency range 2 (FR2). The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges (FR1 and FR2) can be shown in Table 1 below. For ease of explanation, in the frequency range used in the NR system, FR1 can mean "a range below 6 GHz", FR2 can mean "a range above 6 GHz", and can be referred to as millimeter wave (mmW).

[0052] [Table 1]

[0053] Frequency range name Corresponding frequency range Subcarrier spacing FR1 450MHz-6000MHz 15, 30, 60kHz FR2 24250MH-52600MHz 60, 120, 240kHz

[0054] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a frequency band of 410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6 GHz (or 5850 MHz, 5900 MHz, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850 MHz, 5900 MHz, 5925 MHz, etc.) or higher included in FR1 may include an unlicensed frequency band. The unlicensed frequency band can be used for various purposes, for example, for communication of vehicles (e.g., autonomous driving).

[0055] [Table 2]

[0056] Frequency range name Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0057] Here, the radio communication technology implemented in the wireless device in the present disclosure may include narrowband Internet of Things (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of a low-power wide area network (LPWAN) technology, may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the above names. Additionally and / or alternatively, the radio communication technology implemented in the wireless device in the present disclosure may communicate based on LTE-M technology. For example, LTE-M technology may be an example of an LPWAN technology and may be referred to by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in at least one of various specifications, such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE machine type communication and / or 7) LTE M, and may not be limited to the above names. Additionally and / or alternatively, the radio communication technology implemented in the wireless device of the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN considering low-power communication, and may not be limited to the above names. For example, ZigBee technology can generate a personal area network (PAN) associated with small / low-power digital communication based on various specifications (such as IEEE 802.15.4) and may be referred to by various names. Figure 2 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0058] exist Figure 2 In the embodiment, the first wireless device 100 and / or the second wireless device 200 may be implemented in various forms according to the use case / service. For example, {the first wireless device 100 and the second wireless device 200} may correspond to Figure 1At least one of {wireless devices 100a to 100f and BS 200}, {wireless devices 100a to 100f and wireless devices 100a to 100f} and / or {BS 200 and BS 200}. The first wireless device 100 and / or the second wireless device 200 may be configured by various elements, devices / components and / or modules.

[0059] The first wireless device 100 may include at least one transceiver (eg, transceiver 106 ), at least one processing chip (eg, processing chip 101 ), and / or one or more antennas 108 .

[0060] The processing chip 101 may include at least one processor (eg, processor 102 ) and at least one memory (eg, memory 104 ). Additionally and / or alternatively, the memory 104 may be located outside the processing chip 101 .

[0061] The processor 102 may control the memory 104 and / or the transceiver 106 and may be adapted to implement the descriptions, functions, processes, suggestions, methods, and / or operational flow charts described in the present disclosure. For example, the processor 102 may process information in the memory 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the transceiver 106. The processor 102 may receive a radio signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory 104.

[0062] Memory 104 may be operatively connected to processor 102. Memory 104 may store various types of information and / or instructions. Memory 104 may store firmware and / or software code 105 that implements codes, commands, and / or command sets that, when executed by processor 102, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, firmware and / or software code 105 may implement instructions that, when executed by processor 102, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, firmware and / or software code 105 may control processor 102 to execute one or more protocols. For example, firmware and / or software code 105 may control processor 102 to execute one or more layers of a wireless interface protocol.

[0063] In this document, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals via one or more antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In this disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0064] The second wireless device 200 may include at least one transceiver (eg, transceiver 206 ), at least one processing chip (eg, processing chip 201 ), and / or one or more antennas 208 .

[0065] The processing chip 201 may include at least one processor (eg, processor 202 ) and at least one memory (eg, memory 204 ). Additionally and / or alternatively, the memory 204 may be located outside the processing chip 201 .

[0066] The processor 202 may control the memory 204 and / or the transceiver 206 and may be adapted to implement the descriptions, functions, processes, suggestions, methods, and / or operational flow charts described in the present disclosure. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204.

[0067] Memory 204 may be operatively connected to processor 202. Memory 204 may store various types of information and / or instructions. Memory 204 may store firmware and / or software code 205 that implements code, commands, and / or command sets that, when executed by processor 202, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, firmware and / or software code 205 may implement instructions that, when executed by processor 202, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, firmware and / or software code 205 may control processor 202 to execute one or more protocols. For example, firmware and / or software code 205 may control processor 202 to execute one or more layers of a wireless interface protocol.

[0068] In this document, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals via one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In this disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0069] In the following, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but are not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). The one or more processors 102 and 202 may generate one or more protocol data units (PDUs), one or more service data units (SDUs), messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure.

[0070] One or more processors 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. For example, one or more processors 102 and 202 may be configured by a group of communication control processors, application processors (APs), electronic control units (ECUs), central processing units (CPUs), graphics processing units (GPUs), and memory control processors.

[0071] One or more memories 104 and 204 can be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions and / or commands. One or more memories 104 and 204 can be configured by random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EPROM), flash memory, volatile memory, non-volatile memory, hard drive, registers, cache memory, computer-readable storage media and / or combinations thereof. One or more memories 104 and 204 can be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 can be connected to one or more processors 102 and 202 via various technologies such as wired connections or wireless connections.

[0072] One or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels as described in the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels as described in the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and transmit and receive radio signals. For example, one or more processors 102 and 202 may control one or more transceivers 106 and 206 to transmit user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may control one or more transceivers 106 and 206 to receive user data, control information, or radio signals from one or more other devices.

[0073] One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208. Additionally or alternatively, one or more transceivers 106 and 206 may include one or more antennas 108 and 208. One or more transceivers 106 and 206 may be adapted to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure through one or more antennas 108 and 208. In the present disclosure, one or more antennas 108 and 208 may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0074] The one or more transceivers 106 and 206 may convert received user data, control information, radio signals / channels, etc. from RF band signals to baseband signals so that the received user data, control information, radio signals / channels, etc. may be processed by the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed by the one or more processors 102 and 202 from baseband signals to RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, under the control of the one or more processors 102 and 202, the one or more transceivers 106 and 206 may up-convert an OFDM baseband signal into an OFDM signal through their (analog) oscillators and / or filters and transmit the up-converted OFDM signal at the carrier frequency. One or more transceivers 106 and 206 may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal through their (analog) oscillators and / or filters under the control of one or more processors 102 and 202 .

[0075] although Figure 2 Although not shown in the figures, the wireless devices 100 and 200 may further include additional components. The additional components 140 may be configured differently depending on the type of the wireless devices 100 and 200. For example, the additional components 140 may include at least one of a power supply unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a drive device, and a computing device. The additional components 140 may be coupled to one or more processors 102 and 202 via various technologies, such as a wired or wireless connection.

[0076] In implementations of the present disclosure, a UE may function as a transmitting device in the uplink (UL) and a receiving device in the downlink (DL). In implementations of the present disclosure, a base station (BS) may function as a receiving device in the UL and a transmitting device in the DL. Hereinafter, for ease of description, it is primarily assumed that a first wireless device 100 functions as a UE and a second wireless device 200 functions as a base station (BS). For example, a processor 102 connected to, installed on, or activated in the first wireless device 100 may be adapted to perform UE behavior according to implementations of the present disclosure or to control a transceiver 106 to perform UE behavior according to implementations of the present disclosure. A processor 202 connected to, installed on, or activated in the second wireless device 200 may be adapted to perform BS behavior according to implementations of the present disclosure or to control a transceiver 206 to perform BS behavior according to implementations of the present disclosure.

[0077] In this disclosure, a BS is also referred to as a Node B (NB), an eNode B (eNB), or a gNB.

[0078] Figure 3 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0079] Reference Figure 3 , UE 100 may correspond to Figure 2 The first wireless device 100 is configured to:

[0080] UE 100 includes a processor 102 , memory 104 , a transceiver 106 , one or more antennas 108 , a power management module 141 , a battery 142 , a display 143 , a keypad 144 , a subscriber identity module (SIM) card 145 , a speaker 146 , and a microphone 147 .

[0081] The processor 102 may be adapted to implement the descriptions, functions, processes, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The processor 102 may be adapted to control one or more other components of the UE 100 to implement the descriptions, functions, processes, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The radio interface protocol layer may be implemented in the processor 102. The processor 102 may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor 102 may be an application processor. The processor 102 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a modem (modulator and demodulator). Examples of the processor 102 may be SNAPDRAGON MANUFACTURED TM series processors, Manufactured by EXYNOS TM series processors, A series of processors manufactured by Manufactured by HELIO TM series processors, ATOM manufactured TM series processors or the corresponding next-generation processors.

[0082] The memory 104 is coupled to the processor 102 during operation and stores various information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, memory card, storage medium, and / or other storage devices. When the embodiment is implemented in software, the technology described herein may be implemented using modules (e.g., processes, functions, etc.) that execute the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. The modules may be stored in the memory 104 and implemented by the processor 102. The memory 104 may be implemented within the processor 102 or external to the processor 102 (in which case, the memory may be communicatively coupled to the processor 102 via various means known in the art).

[0083] The transceiver 106 is coupled to the processor 102 during operation and transmits and / or receives radio signals. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include baseband circuitry to process radio frequency signals. The transceiver 106 controls one or more antennas 108 to transmit and / or receive radio signals.

[0084] The power management module 141 manages the power of the processor 102 and / or the transceiver 106. The battery 142 provides power to the power management module 141.

[0085] The display 143 outputs a result processed by the processor 102. The keypad 144 receives an input to be used by the processor 102. The keypad 144 may be displayed on the display 143.

[0086] The SIM card 145 is an integrated circuit designed to securely store an International Mobile Subscriber Identity (IMSI) number and its associated keys, which are used to identify and authenticate subscribers on mobile telephony devices such as mobile phones and computers. Contact information can also be stored on many SIM cards.

[0087] The speaker 146 outputs sound-related results processed by the processor 102. The microphone 147 receives sound-related input to be used by the processor 102.

[0088] Figure 4 and Figure 5 An example of a protocol stack in a 3GPP-based wireless communication system to which implementations of the present disclosure are applied is shown.

[0089] Specifically, Figure 4 An example of a radio interface user plane protocol stack between a UE and a BS is illustrated, and Figure 5 An example of a radio interface control plane protocol stack between a UE and a BS is illustrated. The control plane refers to a path for transmitting control messages used by the UE and the network to manage calls. The user plane refers to a path for transmitting data generated in the application layer (for example, voice data or Internet packet data). Figure 4 , the user plane protocol stack can be divided into layer 1 (L1, for example, PHY layer) and layer 2 (L2, for example, MAC / RLC / PDCP layer). Figure 5 The control plane protocol stack can be divided into Layer 1 (L1, e.g., PHY layer), Layer 2 (L2, e.g., MAC / RLC / PDCP layer), Layer 3 (L3, e.g., RRC layer), and Non-Access Stratum (NAS) layer. Layer 1, Layer 2, and Layer 3 are called Access Stratum (AS).

[0090] In 3GPP LTE systems, Layer 2 is divided into the following sublayers: MAC, RLC, and PDCP. In 3GPP NR systems, Layer 2 is divided into the following sublayers: MAC, RLC, PDCP, and SDAP. The PHY layer provides transport channels to the MAC sublayer, the MAC sublayer provides logical channels to the RLC sublayer, the RLC sublayer provides RLC channels to the PDCP sublayer, and the PDCP sublayer provides radio bearers to the SDAP sublayer. The SDAP sublayer provides Quality of Service (QoS) flows to the 5G core network.

[0091] In 3GPP NR systems, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing MAC SDUs belonging to one or different logical channels into / demultiplexing transport blocks (TBs) delivered to / from the physical layer on the transport channel; scheduling information reporting; error correction through hybrid automatic repeat request (HARQ) (one HARQ entity per cell in the case of carrier aggregation (CA); priority handling between UEs with dynamic scheduling; priority handling between logical channels of a UE with logical channel prioritization; and padding. A single MAC entity can support multiple parameter sets, transmission timings, and cells. Mapping restrictions in logical channel prioritization control which parameter set(s), cell, and transmission timing can be used by a logical channel.

[0092] MAC provides different types of data transmission services. In order to accommodate different types of data transmission services, multiple types of logical channels are defined, that is, each logical channel supports the transmission of a specific type of information. Each logical channel type is defined by what type of information is transmitted. Logical channels are divided into two groups: control channels and traffic channels. Control channels are only used for the transmission of control plane information, and traffic channels are only used for the transmission of user plane information. The Broadcast Control Channel (BCCH) is a downlink logical channel used to broadcast system control information, the Paging Control Channel (PCCH) is a downlink logical channel that transmits paging information, system information change notifications, and indications of ongoing Public Warning Service (PWS) broadcasts, the Common Control Channel (CCCH) is a logical channel used to send control information between the UE and the network and is used for UEs that do not have an RRC connection with the network, and the Dedicated Control Channel (DCCH) is a point-to-point bidirectional logical channel that sends dedicated control information between the UE and the network and is used by UEs with an RRC connection. The Dedicated Traffic Channel (DTCH) is a point-to-point logical channel dedicated to one UE, which is used to transmit user information. The DTCH can exist in both the uplink and downlink. In the downlink, the following connections exist between logical channels and transport channels: BCCH can be mapped to the broadcast channel (BCH); BCCH can be mapped to the downlink shared channel (DL-SCH); PCCH can be mapped to the paging channel (PCH); CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In the uplink, the following connections exist between logical channels and transport channels: CCCH can be mapped to the uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0093] The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). RLC configuration is specific to each logical channel and is independent of the parameter set and / or transmission duration. In 3GPP NR systems, the main services and functions of the RLC sublayer depend on the transmission mode and include: delivery of upper layer PDUs; sequence numbering independent of either PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDUs (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; and protocol error detection (AM only).

[0094] In the 3GPP NR system, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression using Robust Header Compression (ROHC); delivery of user data; reordering and duplicate detection; in-sequence delivery; PDCP PDU routing (in the case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering, and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; PDCP PDU duplication and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering, and integrity protection; delivery of control plane data; reordering and duplicate detection; in-sequence delivery; PDCP PDU duplication and duplicate discard indication to lower layers.

[0095] In 3GPP NR systems, the main services and functions of SDAP include: mapping between QoS flows and data radio bearers; marking QoS flow IDs (QFIs) in both DL and UL packets; and configuring a single SDAP protocol entity for each individual PDU session.

[0096] In the 3GPP NR system, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance and release of RRC connection between UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer; UE cell selection and reselection and control of cell selection and reselection; inter-RAT mobility); QoS management functions; UE measurement reporting and control of reporting; detection and repair of radio link failure; transmission of NAS messages from UE to NAS / from NAS to UE.

[0097] Figure 6 The frame structure in a 3GPP-based wireless communication system to which the implementation of the present disclosure is applied is shown.

[0098] Figure 6The frame structure shown is only exemplary, and the number of subframes, the number of time slots and / or the number of symbols in a frame may vary. In a 3GPP-based wireless communication system, OFDM parameter sets (e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration) may be configured differently between multiple cells aggregated for one UE. For example, if a UE is configured with different SCSs for cells aggregated for a cell, the (absolute time) duration of time resources (e.g., subframes, time slots, or TTIs) comprising the same number of symbols may be different among the aggregated cells. In this document, symbols may include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbols).

[0099] Reference Figure 6 , downlink and uplink transmissions are organized into frames. Each frame has T f =10ms duration. Each frame is divided into two half-frames, where each half-frame has a duration of 5ms. Each half-frame includes 5 sub-frames, where the duration of each sub-frame is T sf is 1 ms. Each subframe is divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on the cyclic prefix (CP). In normal CP, each slot includes 14 OFDM symbols, and in extended CP, each slot includes 12 OFDM symbols. The parameter set is based on an exponentially scalable subcarrier spacing βf=2 u *15kHz.

[0100] Table 3 shows the subcarrier spacing βf=2 u *N number of OFDM symbols per slot for normal CP of 15 kHz slot symb , the number of time slots per frame N frame，u slot and the number of time slots per subframe N subframe，u slot .

[0101] [Table 3]

[0102] u <![CDATA[N slot symb ]]> <![CDATA[N frame，u slot ]]> <![CDATA[N subframe，u slot ]]> 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

[0103] Table 4 shows the subcarrier spacing βf=2 u *N number of OFDM symbols per slot for extended CP of 15 kHz slot symb , the number of time slots per frame N frame，u slot and the number of time slots per subframe Nsubframe，u slot .

[0104] [Table 4]

[0105] u <![CDATA[N slot symb ]]> <![CDATA[N frame，u slot ]]> <![CDATA[N subframe，u slot ]]> 2 12 40 4

[0106] A slot includes a plurality of symbols (e.g., 14 or 12 symbols) in the time domain. For each parameter set (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N indicated by higher layer signaling (e.g., RRC signaling) is defined. start，u grid Starting N size，u grid，x *N RB sc subcarriers and N subframe，u symb OFDM symbol resource grid, where N size，u grid，x is the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for the downlink and UL for the uplink. N RB sc is the number of subcarriers per RB. In 3GPP-based wireless communication systems, N RB sc Typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL), there is one resource grid. The carrier bandwidth N for subcarrier spacing configuration u size,u grid Given by high-level parameters (e.g., RRC parameters). Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and one complex symbol can be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l in the time domain that represents the symbol position relative to a reference point. In a 3GPP-based wireless communication system, an RB is defined by 12 consecutive subcarriers in the frequency domain. Figure 6As shown in the figure, as the SCS is doubled, the slot length and symbol length are halved. For example, when the SCS is 15kHz, the slot length is 1ms, which is the same as the subframe length. When the SCS is 30kHz, the slot length is 0.5ms (=500us), and the symbol length is half of the symbol length when the SCS is 15kHz. When the SCS is 60kHz, the slot length is 0.25ms (=250us), and the symbol length is half of the symbol length when the SCS is 30kHz. When the SCS is 120kHz, the slot length is 0.125ms (=125us), and the symbol length is half of the symbol length when the SCS is 60kHz. When the SCS is 240kHz, the slot length is 0.0625ms (=62.5us), and the symbol length is half of the symbol length when the SCS is 120kHz.

[0107] In 3GPP NR systems, RBs are classified into CRBs and physical resource blocks (PRBs). For subcarrier spacing configuration u, CRBs are numbered from 0 upwards in the frequency domain. The center of subcarrier 0 of CRB0 for subcarrier spacing configuration u coincides with "point A", which is used as a common reference point for the resource block grid. In 3GPP NR systems, PRBs are defined within a bandwidth part (BWP) and are numbered from 0 to N. size BWP,i -1 numbering, where i is the number of bandwidth parts. Physical resource blocks n in bandwidth part i PRB With public resource block n CRB The relationship between them is as follows: PRB =n CRB +N size BWP,i , where N size BWP,i A BWP is a common resource block where the bandwidth portion begins relative to CRB0. A BWP consists of multiple contiguous RBs. A carrier can include up to N (e.g., 5) BWPs. A UE can be configured with one or more BWPs on a given component carrier. Only one BWP configured for a UE can be active at a time. The active BWP defines the UE's operating bandwidth within the cell's operating bandwidth.

[0108] In the present disclosure, the term "cell" may refer to a geographical area in which one or more nodes provide a communication system or to a radio resource. A "cell" as a geographical area may be understood as a coverage area within which a node can provide services using a carrier, and a "cell" as a radio resource (e.g., a time-frequency resource) is associated with a bandwidth that is a frequency range configured by a carrier. A "cell" associated with a radio resource is defined by a combination of downlink resources and uplink resources (e.g., a combination of a DL component carrier (CC) and a ULCC). A cell may be configured only by downlink resources, or may be configured by downlink resources and uplink resources. Since the DL coverage (which is the range within which a node can send a valid signal) and the UL coverage (which is the range within which a node can receive a valid signal from a UE) depend on the carrier carrying the signal, the coverage of a node may be associated with the coverage of a "cell" of the radio resource used by the node. Therefore, the term "cell" may sometimes be used to refer to the service coverage of a node, at other times to refer to a radio resource, or at other times to refer to a range within which a signal using a radio resource can reach with effective strength.

[0109] In CA, two or more CCs are aggregated. The UE can receive or transmit on one or more CCs simultaneously depending on its capabilities. CA is supported for both contiguous CCs and non-contiguous CCs. When CA is configured, the UE has only one RRC connection with the network. During RRC connection establishment / reestablishment / handover, one serving cell provides NAS mobility information, and during RRC connection reestablishment / handover, one serving cell provides security input. This cell is called a primary cell (PCell). A PCell is a cell operating on the primary frequency, where the UE performs an initial connection establishment procedure or initiates a connection reestablishment procedure. Depending on the UE capabilities, a secondary cell (SCell) can be configured to form a set of serving cells together with the PCell. An SCell is a cell that provides additional radio resources on top of a special cell (SpCell). Therefore, the set of serving cells configured for a UE always consists of one PCell and one or more SCells. For dual connectivity (DC) operation, the term SpCell refers to the PCell of a primary cell group (MCG) or the primary SCell (PSCell) of a secondary cell group (SCG). SpCell supports PUCCH transmission and contention-based random access and is always activated. MCG is a group of serving cells associated with a master node, which includes SpCell (PCell) and optionally one or more SCells. For UEs configured with DC, SCG is a subset of serving cells associated with a secondary node, which includes PSCell and zero or more SCells. For RRC_CONNECTED UEs not configured with CA / DC, there is only one serving cell consisting of PCell. For RRC_CONNECTED UEs configured with CA / DC, the term "serving cell" is used to refer to a set of cells consisting of SpCell and all SCells. In DC, two MAC entities are configured in the UE: one for MCG and one for SCG.

[0110] Figure 7 An example of data flow in a 3GPP NR system to which an implementation of the present disclosure is applied is shown.

[0111] Reference Figure 7 "RB" stands for radio bearer, and "H" stands for header. Radio bearers are categorized into two groups: DRBs for user plane data and SRBs for control plane data. MAC PDUs are transmitted and received to and from external devices via the PHY layer using radio resources. MAC PDUs arrive at the PHY layer in the form of transport blocks.

[0112] In the PHY layer, the uplink transport channels UL-SCH and RACH are mapped to their physical channels, the physical uplink shared channel (PUSCH) and the physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH, and PCH are mapped to the physical downlink shared channel (PDSCH), the physical broadcast channel (PBCH), and the PDSCH, respectively. In the PHY layer, uplink control information (UCI) is mapped to the physical uplink control channel (PUCCH), and downlink control information (DCI) is mapped to the physical downlink control channel (PDCCH). The UE sends a MAC PDU related to the UL-SCH via the PUSCH based on the UL grant, and the BS sends a MAC PDU related to the DL-SCH via the PDSCH based on the DL assignment.

[0113] Next, the content regarding mobility is described.

[0114] Mobility may include PCell change, PSCell change (or Secondary Node (SN) change) and / or PSCell addition (or SN addition).

[0115] In the present disclosure, the term "handover (HO)" may refer to a PCell change, or may be a broad concept including not only a PCell change but also a PSCell change / addition.

[0116] In the present disclosure, descriptions about handover may also be applied to other mobility procedures (eg, PSCell change / addition).

[0117] In this disclosure, the terms "handover", "mobility" and "cell switching" may be used interchangeably.

[0118] Figure 8 An example of a traditional handover process to which the technical features of the present disclosure can be applied is shown.

[0119] Reference Figure 8 In step S801, the source RAN node may send a measurement control message to the UE. The source RAN node may use the measurement control message to configure the UE's measurement process based on roaming and access restriction information, and, for example, available multi-band information. The measurement control information provided by the source RAN node via the measurement control message may assist in controlling the UE's connection mobility. For example, the measurement control message may include measurement configuration and / or reporting configuration.

[0120] In step S803, the UE may send a measurement report message to the source RAN node. The measurement report message may include the results of measurements of neighboring cells around the UE that may be detected by the UE. The UE may generate the measurement report message based on the measurement configuration and / or measurement control information in the measurement control message received in step S801.

[0121] In step S805, the source RAN node may make a handover (HO) decision based on the measurement report. For example, the source RAN node may make a HO decision and determine a target RAN node for HO among neighboring cells around the UE based on measurement results of neighboring cells (e.g., cell quality, signal quality, signal strength, reference signal received power (RSRP), reference signal received quality (RSRP), channel state, channel quality, signal to interference plus noise ratio (SINR)).

[0122] In step S807, the source RAN node may send a HO request message to the target RAN node determined in step S805. That is, the source RAN node may perform handover preparation with the target RAN node. The HO request message may include necessary information for preparing the handover at the target RAN node.

[0123] In step S809, the target RAN node may perform admission control based on the information included in the HO request message. The target RAN node may configure and reserve the required resources (e.g., C-RNTI and / or RACH preamble). The AS configuration to be used in the target RAN node may be specified independently (i.e., "establish") or as an increment compared to the AS configuration used in the source cell (i.e., "reconfigure").

[0124] In step S811, the target RAN node may send a HO Request Acknowledgement (ACK) message to the source RAN node. The HO Request ACK message may include information about the resources reserved and prepared for the handover. For example, the HO Request ACK message may include a transparent container to be sent to the UE as an RRC message to perform the handover. The container may include a new C-RNTI, a target gNB security algorithm identifier for the selected security algorithm, a dedicated RACH preamble, and / or possibly some other parameters, i.e., access parameters SIB. If a RACH-less handover is configured, the container may include a timing adjustment indication and an optional pre-allocated uplink grant. If required, the HO Request ACK message may also include RNL / TNL information for the forwarding tunnel. Once the source RAN node receives the HO Request ACK message, or once the transmission of the handover command is initiated in the downlink, data forwarding may be initiated.

[0125] In step S813, the source RAN node may send a handover command to the UE. For example, the handover command may include or may be a cell configuration (i.e., an RRCReconfiguration message including a ReconfigurationWithSync message). The RRCReconfiguration message and / or ReconfigurationWithSync message of the target cell may include information required to access the target cell (i.e., access configuration), including the physical cell ID of the target cell, the identifier of the UE (i.e., C-RNTI), a HO validity timer (i.e., T304 timer), a target gNB security algorithm identifier for the selected security algorithm, a dedicated RACH resource set for contention-free random access (e.g., a dedicated random access preamble), an association between RACH resources and SSBs, an association between RACH resources and UE-specific CSI-RS configurations, common RACH resources, or at least one of system information of the target cell. The source RAN node may perform necessary integrity protection and encryption of the message.

[0126] In step S815, the UE may be handed over to the new cell, i.e., the target RAN node. The UE may detach from the old cell (i.e., the source RAN node) and synchronize to the new cell (i.e., the target RAN node). The UE may perform a handover from the source RAN node to the target RAN node based on the applied cell configuration. For example, upon receiving the handover command, the UE may start the T304 timer and perform a contention-free random access to the target RAN node based on a dedicated RACH resource set.

[0127] In step S817, upon successful completion of the random access procedure, the UE may stop the T304 timer and send a handover complete message (i.e., an RRCReconfigurationComplete message) to the target RAN node. The UE may send an RRCReconfigurationComplete message to the target RAN node to confirm the C-RNTI for the handover, indicating that the handover procedure for the UE is complete. The target RAN node may verify the C-RNTI sent in the RRCReconfigurationComplete message. The target RAN node may now start sending data to the UE. When random access fails and the T304 timer is still running, the UE may retry random access towards the target RAN node. When the T304 timer expires, the UE may declare a handover failure (HOF) and perform an RRC reestablishment procedure.

[0128] Figure 9 An example of a conditional handover process to which the technical features of the present disclosure can be applied is shown.

[0129] Reference Figure 9 In step S901, the source cell may send a measurement control message to the UE. The measurement control message may include a measurement configuration including a measurement configuration list, and each measurement configuration in the list includes a measurement identifier (ID), a corresponding measurement object, and a corresponding reporting configuration.

[0130] In step S903, the UE may send a measurement report message to the source cell. The measurement report message may include the results of measurements of neighboring cells around the UE that may be detected by the UE. The UE may generate the measurement report message based on the measurement configuration and / or measurement control information in the measurement control message received in step S901.

[0131] In step S905, the source cell may make a handover decision based on the measurement report. For example, the source cell may make a handover decision and determine candidate target cells for handover (e.g., target cell 1 and target cell 2) among neighboring cells around the UE based on measurement results (e.g., signal quality, reference signal received power (RSRP), reference signal received quality (RSRP)) of neighboring cells.

[0132] In step S907, the source cell may send a handover request message to the target cell 1 and the target cell 2 determined in step S905. That is, the source cell may perform handover preparation with the target cell 1 and the target cell 2. The handover request message may include necessary information for preparing the handover on the target side (e.g., the target cell 1 and the target cell 2).

[0133] In step S909, each of target cell 1 and target cell 2 may perform admission control based on the information included in the handover request message. The target cell may configure and reserve required resources (e.g., C-RNTI and / or RACH preamble). The AS configuration to be used in the target cell may be specified independently (i.e., "establish") or as an increment compared to the AS configuration used in the source cell (i.e., "reconfiguration").

[0134] In step S911, the target cell and target cell 2 may send a Handover Request Acknowledgement (ACK) message to the source cell. The Handover Request ACK message may include a cell configuration (i.e., an RRCReconfiguration message including ReconfigurationWithSync), which includes information about resources reserved and prepared for the handover. For example, the Handover Request ACK message may include a transparent container to be sent as an RRC message (i.e., an RRCReconfiguration message / cell configuration) to the UE to perform the handover. The container / cell configuration / RRCReconfiguration message may include information required to access the target cell (i.e., access configuration), including at least one of the target cell's physical cell ID, the UE's identifier (i.e., C-RNTI), a HO validity timer (i.e., T304 timer), a target gNB security algorithm identifier for the selected security algorithm, a dedicated RACH resource set for contention-free random access (e.g., a dedicated random access preamble), an association between RACH resources and SSBs, an association between RACH resources and UE-specific CSI-RS configurations, common RACH resources, or system information of the target cell. If RACH-less handover is configured, the container may include a timing adjustment indication and, optionally, a pre-allocated uplink grant. The Handover Request ACK message may also include RNL / TNL information for the forwarding tunnel, if required. Data forwarding may be initiated upon receipt of the Handover Request ACK message by the source cell, or upon initiation of transmission of a conditional handover command in the downlink.

[0135] In step S913, the source cell may send an RRCReconfiguration message including conditional reconfiguration to the UE. Conditional reconfiguration may also be referred to as (or may include) conditional handover (CHO) configuration and / or conditional handover command (e.g., CHO command). The conditional reconfiguration may include a list of conditional reconfiguration / conditional handover commands, which includes a conditional reconfiguration / conditional handover command for each candidate target cell (e.g., target cell 1, target cell 2). For example, the conditional reconfiguration may include a conditional reconfiguration / conditional handover command for target cell 1, and a conditional reconfiguration / conditional handover command for target cell 2. The conditional reconfiguration for the target cell may include an index / identifier identifying the corresponding conditional reconfiguration, a handover condition for the target cell, and / or a cell configuration for the target cell (i.e., an RRCReconfiguration message including ReconfigurationWithSync). The RRCReconfiguration message and / or ReconfigurationWithSync for the target cell may include information required to access the target cell, including the physical cell ID of the target cell, an identifier of the UE (i.e., C-RNTI), a HO validity timer (i.e., T304 timer), a target gNB security algorithm identifier for the selected security algorithm, a dedicated RACH resource set for contention-free random access (e.g., a dedicated random access preamble), an association between RACH resources and SSBs, an association between RACH resources and UE-specific CSI-RS configuration, common RACH resources, or at least one of system information of the target cell.

[0136] In step S915, the UE may evaluate the handover conditions for the candidate target cells (e.g., target cell 1, target cell 2) and select a target cell for handover from among the candidate target cells. For example, the UE may perform measurements on the candidate target cells and determine, based on the measurement results of the candidate target cells, whether the candidate target cells meet the handover conditions of the candidate target cells. Alternatively, the UE may determine whether the measurement results of the target cell / target cells meet the handover conditions of the target cells. If the UE identifies that target cell 1 meets the handover conditions for target cell 1, the UE may select target cell 1 as the target cell for handover.

[0137] In step S917, the UE may detach from the old cell (i.e., the source cell) and synchronize to the new cell (i.e., the selected target cell). The UE may perform a handover from the source cell to the target cell based on the applied cell configuration. For example, upon receiving the handover command, the UE may start the T304 timer and perform contention-free random access to the target cell based on a dedicated RACH resource set.

[0138] In step S919, upon successful completion of the random access procedure, the UE may stop the T304 timer and send a handover complete message (i.e., an RRCReconfigurationComplete message) to the target cell. The UE may send an RRCReconfigurationComplete message including a C-RNTI for confirming the handover to the target cell to indicate that the handover procedure for the UE is complete. The target RAN node may verify the C-RNTI sent in the RRCReconfigurationComplete message. The target RAN node may now start sending data to the UE. When random access fails and the T304 timer is still running, the UE may retry random access towards the target cell. When the T304 timer expires, the UE may declare a handover failure (HOF) and perform an RRC reestablishment procedure.

[0139] Hereinafter, L1 / L2 triggered mobility (LTM) is described.

[0140] LTM is a procedure in which the gNB receives L1 measurement reports from the UE and, based on these reports, changes the UE's serving cell via MAC CE. The gNB prepares one or more candidate cells and provides the candidate cell configurations to the UE via RRC messages. LTM cell handover is then triggered by the gNB selecting one of the candidate configurations as the target configuration for LTM. Candidate cell configurations can only be added, modified, and released by the network via RRC signaling.

[0141] The LTM candidate cells may be configured via an RRCReconfiguration message for the candidate target cells and / or a CellGroupConfig IE for each candidate target cell.

[0142] The following principles can be applied to LTM:

[0143] -Candidate cell configurations may be provided as incremental configurations on top of a reference configuration. The reference configuration is managed separately and the UE stores the reference configuration as a separate configuration.

[0144] - Allow the user plane to continue without resetting whenever possible (e.g. within a distributed unit, DU), with the goal of avoiding data loss and additional delays in data recovery.

[0145] - Security is not updated in LTM.

[0146] - Subsequent LTM between candidates (i.e., the UE does not release other candidate cell configurations after LTM is triggered) can be performed without RRC reconfiguration.

[0147] LTM supports both intra-gNB-DU and intra-gNB-CU mobility. LTM also supports inter-frequency mobility, including mobility to an inter-frequency cell that is not the current serving cell. The following scenarios are supported:

[0148] - PCell changes in non-CA scenarios,

[0149] - PCell change without SCell change in CA scenario,

[0150] -PCell changes with SCell changes in CA scenarios include the following:

[0151] a) The target PCell / target SCell is not the current serving cell (CA to CA scenario with PCell change)

[0152] b) The target PCell is the current SCell

[0153] c) The target SCell is the current PCell.

[0154] - Dual connectivity scenarios (at least for PSCell change cases without MN involvement, ie intra-SN).

[0155] Inter-cell beam management is also supported but is not considered a prerequisite for using LTM.

[0156] The design of L1 / L2-based intra-DU and inter-DU mobility should share as much commonality as possible within a reasonable range.

[0157] In some implementations, upon receiving a candidate cell configuration, a validity / compliance check of the candidate cell configuration is performed.

[0158] The cell handover trigger information is transmitted in a MAC CE, which contains at least a candidate configuration index. The cell-specific configuration, radio bearer configuration, and measurement configuration may be part of the LTM candidate cell configuration.

[0159] In some implementations, the MAC CE may indicate the TCI state (or other beam information) to be activated for the target cell.

[0160] In some implementations, SCell activation / deactivation (among SCells associated with the candidate configuration) may be performed concurrently with the LTM triggering the MAC CE.

[0161] The UE can perform contention-based random access (CBRa) or contention-free random access (CFRa) during cell handover. If the UE does not need to acquire timing advance (TA) for the target cell during cell handover, the UE can also skip the random access procedure. The RACH resources used for CFRA are provided in the RRC configuration.

[0162] In some implementations, CFRA resources may be provided via a MAC CE.

[0163] The overall process of LTM is as follows Figure 10 Subsequent LTMs are performed by repeating the early synchronization, LTM execution, and LTM completion steps, without releasing other candidate cells after each LTM completion.

[0164] Figure 10 An example of a signaling procedure for an LTM according to an embodiment of the present disclosure is shown.

[0165] Reference Figure 10 In step S1001, the UE may send a MeasurementReport message to the gNB.

[0166] In step S1003, the gNB may decide to use LTM and initiate LTM candidate preparation.

[0167] In step S1005, the gNB may send an RRCReconfiguration message to the UE, where the RRCReconfiguration message includes the configuration of one or more LTM candidate target cells.

[0168] In step S1007, the UE may store the configuration of the LTM candidate target cell and send an RRCReconfigurationComplete message to the gNB.

[0169] In some implementations, the UE may optionally perform early synchronization. In this case, the UE may perform DL synchronization and / or TA acquisition with the candidate target cell before receiving the LTM cell handover command.

[0170] For example, DL synchronization of candidate cells before a cell handover command may be supported based at least on the SSB.

[0171] For example, it is possible to support TA acquisition of candidate cells based on at least a PDCCH-ordered RACH before an LTM cell handover command, wherein the PDCCH order is only triggered by the source cell.

[0172] In step S1009, the UE may perform L1 measurements on the configured LTM candidate target cells and send a low-layer measurement report to the gNB. The low-layer measurement report may be carried on L1 or MAC.

[0173] In step S1011, the gNB may decide to perform LTM cell handover to the target cell.

[0174] In step S1013, the gNB may send a MAC CE triggering LTM cell handover by including the candidate configuration index of the target cell. The UE may switch to the configuration of the LTM candidate target cell.

[0175] In step S1015, the UE may detach from the source cell and apply the target cell configuration. If the TA is not available, the UE may perform a random access procedure towards the target cell.

[0176] In step S1017 , the UE may indicate successful completion of the LTM cell handover towards the target cell.

[0177] In some implementations, an uplink signal or message after the UE has switched to the target cell may be used to indicate successful completion of the LTM cell handover.

[0178] At the same time, L1 / L2 triggered mobility (LTM) is introduced to reduce latency, overhead and interruption time. For LTM, the network can provide the UE with the configuration of the candidate cell in advance (i.e., pre-configuration of the candidate cell for LTM). The UE can then perform L1 measurement of the candidate cell and perform L1 measurement reporting (i.e., report the measurement results of the candidate cell to the network). The network can determine that the UE performs LTM to the candidate cell based on the L1 measurement report. The network can send an LTM command (or a cell handover command) to the UE via L1 / L2 signaling to trigger the UE to perform LTM towards the candidate cell. Upon receiving the LTM command, the UE can perform LTM, for example, the UE can apply the pre-configuration of the candidate cell and then send a UL signal to the candidate cell.

[0179] In traditional conditional handover (CHO), a candidate cell can reserve the resources indicated in the pre-configuration for a UE. The candidate cell will not allocate the resources indicated in the pre-configuration to another UE until the UE applies the candidate cell's configuration or the network releases the candidate cell's pre-configuration.

[0180] In LTM, a UE needs to be configured with multiple candidate cells for dynamic cell switching. Candidate cells in LTM may retain resources for the UE for a long time because the UE does not discard the candidate cell configuration for subsequent LTMs. Furthermore, a single cell can be configured as an LTM candidate cell for multiple UEs. Consequently, a candidate cell may experience resource shortages due to the high number of resources reserved for LTM between pre-configuration and LTM execution.

[0181] In this disclosure, "cell handover" and "LTM execution" may be used interchangeably.

[0182] In this disclosure, "cell switching command" and "LTM command" may be used interchangeably.

[0183] Figure 11 An example of a method performed by a UE according to an embodiment of the present disclosure is shown. The method may also be performed by a wireless device.

[0184] Reference Figure 11 In step S1101, the UE may receive a configuration for a candidate cell for cell handover from the network. The configuration for the candidate cell may include multiple resource configurations for the candidate cell.

[0185] In step S1103, the UE may receive a cell handover command for the candidate cell from the network. The cell handover command may notify a resource configuration among multiple resource configurations for the candidate cell.

[0186] In step S1105 , the UE may perform cell handover to the candidate cell based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

[0187] According to various embodiments, a UE may receive multiple configurations for candidate cells for cell handover from a network, the multiple configurations for the candidate cells including the configuration of the candidate cell. Each of the multiple configurations may be associated with a corresponding candidate cell and include: a candidate configuration index for the configuration of the corresponding candidate cell; and multiple resource configurations associated with the candidate configuration index. Each of the multiple resource configurations may include a resource configuration index for the corresponding resource configuration.

[0188] According to various embodiments, the cell handover command may include: a candidate configuration index for the configuration of the candidate cell; and a resource configuration index of the resource configuration among a plurality of resource configurations associated with the candidate configuration index.

[0189] According to various embodiments, the UE may perform L1 measurement on the candidate cell to obtain an L1 measurement result for the candidate cell. The UE may send an L1 measurement report including the L1 measurement result to the network. The UE may receive a cell handover command after sending the L1 measurement report to the network.

[0190] According to various embodiments, the UE may identify, among multiple configurations for the candidate cell, a configuration for the candidate cell having a candidate configuration index that matches the candidate configuration index in the cell handover command. The UE may identify, among multiple resource configurations in the configuration for the candidate cell, a resource configuration having a resource configuration index that matches the resource configuration index in the cell handover command.

[0191] According to various embodiments, multiple configurations for candidate cells may be received via RRC signaling. A cell handover command may be received via MAC CE signaling.

[0192] According to various embodiments, the cell handover may include LTM. The cell handover command may include an LTM command.

[0193] According to various embodiments, the multiple resource configurations include at least one of: a set of physical channel configurations; a set of DL BWP configurations; a set of UL BWP configurations; a set of SCell states; a set of TA values; a set of TCI states; a set of indications for at least one of PDCP recovery, RLC re-establishment, or MAC reset; a set of SSB indices; a set of CSI-RS indices; or an indication of whether the UE performs random access when performing cell switching.

[0194] According to various embodiments, the set of physical channel configurations may include at least one of: a set of PUCCH configurations; a set of PUSCH configurations; a set of PDCCH configurations; a set of PDSCH configurations; or a set of PRACH configurations.

[0195] According to various embodiments, to perform cell handover, the UE may: apply a configuration for a candidate cell; and transmit one or more UL signals to the candidate cell. The one or more UL signals may include a UL signal transmitted based on the resource configuration notified by the cell handover command.

[0196] According to various embodiments, the cell handover may include RACH-based cell handover. The one or more UL signals may include at least one of the following: a random access preamble sent based on a PRACH configuration notified by a cell handover command; or an RRC reconfiguration complete message sent based on a UL grant provided in a random access response to the random access preamble.

[0197] According to various embodiments, the cell handover may include a RACH-less cell handover. The one or more UL signals may include at least one of the following: a scheduling request sent based on the PUCCH configuration notified by the cell handover command; an LTM completion MAC CE sent based on the first PUSCH configuration notified by the cell handover command; or an RRC reconfiguration complete message sent based on the second PUSCH configuration notified by the cell handover command.

[0198] According to various embodiments, the UE may receive an RRC configuration for a candidate cell from the network. The RRC configuration may include two or more sets of physical channel configurations for the BWP. The UE may receive a cell handover command for the candidate cell from the network. The cell handover command may indicate one of the two or more sets of physical channel configurations. The UE may access the candidate cell based on the indicated set of physical channel configurations.

[0199] According to various embodiments, when a cell handover command is executed, the candidate cell may become the new serving cell.

[0200] According to various embodiments, access to a candidate cell may be based on at least one of: sending an UL signal to the candidate cell via UL resources corresponding to an indicated set of physical channel configurations; or receiving a DL signal from the candidate cell via DL resources corresponding to an indicated set of physical channel configurations.

[0201] Figure 12 An example of a signal flow between a UE and a network node according to an embodiment of the present disclosure is shown. The network node may include a base station (BS) and may be associated with a source cell in a cell handover.

[0202] Reference Figure 12 In step S1201, the network node may send multiple configurations for candidate cells for cell handover to the UE. The multiple configurations for the candidate cells may include a configuration for candidate cell 1 and a configuration for candidate cell 2. Each of the multiple configurations may be associated with a corresponding candidate cell and include: a candidate configuration index for the configuration of the corresponding candidate cell; and multiple resource configurations associated with the candidate configuration index. Each of the multiple resource configurations may include a resource configuration index for the corresponding resource configuration.

[0203] In step S1203, the network node may send a cell handover command to the UE, where the cell handover command includes: i) a candidate configuration index for the configuration of candidate cell 1 (i.e., candidate configuration index 1); and ii) a resource configuration index for a resource configuration among multiple resource configurations in the configuration of candidate cell 1 (i.e., a resource configuration index for candidate configuration index 1). The UE may identify the configuration for candidate cell 1 notified by the candidate configuration index 1 among the multiple configurations for the candidate cell. The UE may identify the resource configuration notified by the resource configuration index 1 among the multiple resource configurations in the configuration for candidate cell 1.

[0204] In step S1205 , the UE may perform cell handover to the candidate cell 1 based on the configuration for the candidate cell 1 notified by the candidate configuration index 1 and / or the resource configuration notified by the resource configuration index.

[0205] According to an implementation of the present disclosure, a network (NW) may pre-configure two or more sets of physical channel configurations for a bandwidth part (BWP) of a candidate cell for a UE. When the NW determines that the UE performs LTM execution to the candidate cell, the candidate cell may reserve the physical channel configuration for the UE in the pre-configured corresponding physical channel configuration set in the first BWP. The NW may then send an LTM command to the UE, indicating that the candidate cell is performing the reserved physical channel configuration for LTM execution. Upon receiving the LTM command from the NW, the UE may perform LTM to the candidate cell, i.e., the UE may apply the pre-configuration using the indication of the LTM command, and then the UE may use the indicated physical channel configuration to send an UL signal to the target cell / candidate cell.

[0206] The NW may pre-configure two or more sets of physical channel configurations for a bandwidth part (BWP) of a candidate cell for a UE. This means that the pre-configured BWP configuration may include multiple sets of physical channel configurations, for example, a set of PUCCH configurations, a set of PUSCH configurations, a set of PDCCH configurations, a set of PDSCH configurations and / or a set of PRACH configurations. The pre-configuration of a candidate cell may include two parts: i) a part that the UE applies directly when LTM is executed; and ii) another part that the UE selectively applies based on the indication included in the LTM command when LTM is executed. The candidate cell then does not reserve resources corresponding to the set of physical channel configurations configured in the pre-configured BWP configuration. This means that the candidate cell may allocate a set of physical channel configurations included in the pre-configuration to another UE until the UE starts applying the pre-configuration (i.e., LTM is executed at the UE).

[0207] When the NW decides that a UE should perform a cell handover to a candidate cell, the candidate cell may reserve a physical channel configuration for the UE from a set of pre-configured corresponding physical channel configurations in the first BWP (referred to as a "corresponding set"). The first BWP that the UE should apply when performing LTM may be indicated by an LTM command or pre-configuration. Negotiation between the source cell and the target cell / candidate cell may be necessary to determine which physical channel configuration from the corresponding set to be indicated to the UE by the LTM command. After negotiation, the target cell / candidate cell may retain the physical channel configuration determined for LTM execution.

[0208] The NW then sends an LTM command to the UE indicating the physical channel configuration that the candidate cell is reserving for LTM execution. The LTM command may indicate the configuration index of the physical channel configuration that the UE should apply when LTM is executed.

[0209] Upon receiving the LTM command from the NW, the UE may perform LTM to the candidate cell. That is, the UE may apply the preconfiguration indicated by the LTM command. The UE may then transmit a first UL signal to the candidate cell. This first signal may be: i) an RA preamble if LTM is performed over RACH; or ii) a scheduling request or a MAC CE indicating the UE's arrival if LTM is performed without RACH. The first UL signal may be transmitted on UL resources corresponding to the indicated physical channel configuration.

[0210] Regarding the signaling of the indication, the indication may be included in the LTM command. The indication may be configured as part of the candidate cell configuration. The indication may be pre-configured as part of the BWP configuration. That is, the indication may be pre-configured per BWP. When multiple BWPs are configured, the indication may be provided in each BWP configuration.

[0211] Figure 13 An example of a method for indicating a physical channel configuration in an LTM according to an embodiment of the present disclosure is shown. The method may be performed by a UE and / or a wireless device.

[0212] Reference Figure 13 In step S1301, the UE may receive one or more candidate cell configurations (i.e., multiple configurations for candidate cells). That is, one or more candidate serving cells may be configured. The (pre-)configuration of the candidate cells may include at least one of the following: a portion that the UE directly applies when LTM is executed; or another portion that the UE selectively applies based on an indication included in an LTM command when LTM is executed.

[0213] The candidate cell configuration may include at least one of the following items:

[0214] -Special cell configuration, for example, servingCellConfigCommon, servingCellConfig, reconfigurationWithSync, and RLF-related configurations;

[0215] -SCell configuration, for example, servingCellConfigCommon, servingCellConfig, smtc, and DRX configuration;

[0216] -MAC / RLC related configuration; or

[0217] - A set of BWP configurations.

[0218] Each BWP configuration may include a flag indicating whether the UE should first apply the corresponding BWP configuration when LTM is executed. A set of resource configurations, such as physical channel configurations (i.e., multiple sets of physical channel configurations), may be included in each BWP configuration. For example, each BWP configuration may include at least one of a set of PUCCH configurations, a set of PUSCH configurations, a set of PDCCH configurations, a set of PDSCH configurations, or a set of PRACH configurations. Each physical channel configuration in the set may include a flag indicating whether the UE should first apply the corresponding physical channel configuration when LTM is executed.

[0219] In step S1303, the UE may receive an LTM command (i.e., a cell handover command) indicating a candidate cell configuration (i.e., a configuration of a candidate cell) and a resource configuration associated with the candidate cell configuration. The LTM command may be sent via L1 / L2 / L3 signaling. The LTM command may be associated with a network-controlled serving cell change or a UE-initiated serving cell change (e.g., conditional mobility).

[0220] The LTM command may include at least one of the following:

[0221] - Target cell information: If the target cell is one of the candidate serving cells pre-configured for the UE, the target cell information may be the identifier of the candidate serving cell / candidate cell configuration indicated by the LTM command. Otherwise (i.e., the target cell is not one of the candidate serving cells pre-configured for the UE), the target cell information may be the configuration used for the target cell / candidate cell configuration (e.g., RRCReconfiguration including reconfigurationWithSync).

[0222] - ConditionalReconfiguration in case of conditional mobility.

[0223] - Indicator indicating that the source cell has changed to a candidate serving cell: For example, this indicator can be a 1-bit indication in the DCI or MAC CE. For example, an LTM command via L1 / L2 signaling can implicitly indicate that the source cell has changed to a candidate serving cell. For example, the target cell can be included in a list, where the list can indicate that the source cell has changed to a candidate serving cell. For example, this indicator can be an explicit RRC Information Element (IE).

[0224] - Configuration (i.e., resource configuration) to be applied by the UE when LTM is executed: For example, the configuration may include a physical channel configuration index indicating a PRACH configuration in a set of PRACH configurations, a PUCCH configuration in a set of PUCCH configurations, a PUSCH configuration in a set of PUSCH configurations, a PDCCH configuration in a set of PDCCH configurations, and / or a PDSCH configuration in a set of PDSCH configurations. The configuration may include a DL / UL BWP index, SCell state, TA information, TCI state, an indication for L2 operation (e.g., PDCP resumption / RLC re-establishment / MAC (full or partial) reset), SSB / CSI-RS, and / or an indication as to whether the UE performs random access when LTM is executed.

[0225] In step S1305 , the UE may apply the candidate cell configuration / resource configuration indicated by the LTM command.

[0226] For example, if the received LTM command has ConditionalReconfiguration (ie, in the case of conditional mobility), the UE may apply the stored configuration of the cell that meets the execution condition (eg, condRRCReconfig).

[0227] For example, if the received LTM command does not have ConditionalReconfiguration (i.e., in the case of legacy mobility), the UE may apply the configuration indicated in the LTM command from the stored candidate cell / candidate cell configuration. If the LTM command includes the configuration (i.e., resource configuration) that the UE is to apply when LTM is executed, the UE may selectively apply the preconfiguration using the indication of the LTM command. For example, if the preconfiguration has a first PRACH configuration and a second PRACH configuration for the BWP, and if the LTM command indicates the first PRACH configuration, the UE applies the first PRACH configuration instead of the second PRACH configuration for the PRACH configuration. Otherwise, if the LTM command does not include the configuration that the UE is to apply when LTM is executed, the UE may directly apply the preconfiguration of the candidate cell.

[0228] In step S1307 , the UE may perform mobility by transmitting a UL signal to a candidate cell (ie, a target cell) based on the indicated resource configuration.

[0229] In some implementations, the UE may send an UL signal to the candidate cell via L1 signaling (e.g., PUCCH, PUSCH, PRACH). For example, in the case of RACH-based LTM execution, the UE may send a random access (Ra) preamble to the candidate cell. For example, in the case of RACH-free LTM execution, the UE may send a scheduling request to the candidate cell.

[0230] In some implementations, the UE may send an UL signal to the candidate cell via L2 signaling (eg, MAC CE). For example, in the case of LTM execution without RACH, the UE may send an LTM completion MAC CE to the candidate cell indicating the UE's arrival.

[0231] In some implementations, the UE may send an UL signal to the candidate cell via L3 signaling (eg, RRCReconfigurationComplete).

[0232] The first UL signal may be sent on UL resources corresponding to the indicated resource configuration (e.g., physical channel configuration). For example, if the LTM command indicates a specific PRACH configuration, the UE may send an RA preamble corresponding to the indicated PRACH configuration. For example, if the LTM command does not include information about the physical channel configuration, and if the BWP configuration applied by the UE during LTM execution has a physical channel configuration, the UE may send the first UL signal on UL resources corresponding to the physical channel configuration in the BWP configuration.

[0233] In some implementations:

[0234] -If the mobility message (i.e., LTM command / cell handover command) is sent via L1 / L2 signaling, the UE can retain the source resources and configuration, and / or perform TA maintenance and beam failure detection (BFD) / radio link monitoring (RLM) on the source cell / target cell.

[0235] - If the mobility message includes an indicator indicating that the source cell is changed to a candidate serving cell, the UE may retain the source resources and configuration, and / or perform TA maintenance and BFD / RLM on the source cell / target cell.

[0236] - Otherwise, the UE may release the source resources and configuration and / or stop DL / UL reception / transmission with the source cell.

[0237] In step S1309, the UE may receive a DL signal from the candidate cell (ie, the target cell).The first DL signal may be transmitted via the PDCCH and / or the PDSCH.

[0238] In addition, the method described in this disclosure from the perspective of the UE (eg, Figure 11 The method in Figure 2 The first wireless device 100 and / or Figure 3 The UE 100 shown in FIG.

[0239] More specifically, the UE includes at least one transceiver, at least one processor, and at least one computer memory that is operatively connected to the at least one processor and stores instructions that perform operations upon execution by the at least one processor.

[0240] The operations include: receiving a configuration for a candidate cell for cell switching from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell switching command for the candidate cell from the network, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell; and performing cell switching to the candidate cell based on the resource configuration notified by the cell switching command in the configuration for the candidate cell.

[0241] In addition, the method described in this disclosure from the perspective of the UE (eg, Figure 11 Methods in ) can be stored in Figure 2 The software code 105 in the memory 104 included in the first wireless device 100 shown in FIG. 1 is executed.

[0242] More specifically, at least one computer-readable medium (CRM) stores instructions that perform operations based on being executed by at least one processor, the operations including: receiving a configuration for a candidate cell for cell switching from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell switching command for the candidate cell from the network, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell; and performing cell switching to the candidate cell based on the resource configuration in the configuration for the candidate cell notified by the cell switching command.

[0243] In addition, the method described in this disclosure from the perspective of the UE (eg, Figure 11 The method in ) can be controlled by Figure 2 The processor 102 and / or control included in the first wireless device 100 shown in FIG. Figure 3 The process is executed by the processor 102 included in the UE 100 shown in FIG.

[0244] More specifically, an apparatus configured / adapted to operate in a wireless communication system (e.g., a wireless device / UE) includes at least one processor and at least one computer memory operatively connected to the at least one processor. The at least one processor is configured / adapted to perform operations including: receiving a configuration for a candidate cell for cell handover from a network, wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; receiving a cell handover command for the candidate cell from the network, wherein the cell handover command notifies a resource configuration from the multiple resource configurations for the candidate cell; and performing a cell handover to the candidate cell based on the resource configuration in the configuration for the candidate cell notified by the cell handover command.

[0245] Furthermore, the method described in this disclosure is from the perspective of a network node associated with a source cell in a cell handover (e.g., Figure 12 The method in Figure 2 The second wireless device 200 shown in FIG.

[0246] More specifically, the network node includes at least one transceiver, at least one processor, and at least one computer memory operatively connected to the at least one processor and storing instructions that perform operations upon execution by the at least one processor.

[0247] The operations include: sending a configuration of a candidate cell for cell switching to a user equipment (UE), wherein the configuration for the candidate cell includes multiple resource configurations for the candidate cell; and sending a cell switching command for the candidate cell to the UE, wherein the cell switching command notifies a resource configuration among the multiple resource configurations for the candidate cell, wherein the cell switching to the candidate cell is performed based on the resource configuration notified by the cell switching command in the configuration for the candidate cell.

[0248] The present disclosure may have various advantageous effects.

[0249] For example, according to the present disclosure, a network (NW) may pre-configure one or more physical channel configurations for a bandwidth part (BWP) of a candidate cell for a UE. When the NW determines that the UE performs LTM execution to the candidate cell, the candidate cell may reserve a physical channel configuration for the UE from among the pre-configured physical channel configurations in the first BWP. The NW may then send an LTM command to the UE to indicate that the candidate cell is performing LTM on the reserved physical channel configuration. Upon receiving the LTM command from the NW, the UE may perform LTM to the candidate cell, i.e., the UE may apply the pre-configuration using the instruction of the LTM command.

[0250] To this end, the network can prevent resource shortage problems by dynamically allocating physical resources for UE use at the time of LTM execution. As a result, the efficiency of network resource utilization can be improved.

[0251] The beneficial effects that can be obtained by the specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, there may be various technical effects that can be understood and / or derived from the present disclosure by a person of ordinary skill in the relevant art. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure.

[0252] The claims in this disclosure may be combined in various ways. For example, the technical features in the method claims of this disclosure may be combined to be implemented or performed in a device, and the technical features in the device claims may be combined to be implemented or performed in a method. Furthermore, the technical features in the method claims and the device claims may be combined to be implemented or performed in a device. Furthermore, the technical features in the method claims and the device claims may be combined to be implemented or performed in a method. Other implementations are within the scope of the appended claims.

Claims

1. A method performed by a user equipment (UE) configured to operate in a wireless communication system, the method comprising the steps of: receiving, from a network, a configuration for a candidate cell for cell handover, wherein the configuration for the candidate cell includes a plurality of resource configurations for the candidate cell; receiving a cell handover command for the candidate cell from the network, wherein the cell handover command notifies a resource configuration among the plurality of resource configurations for the candidate cell; and The cell handover to the candidate cell is performed based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

2. The method according to claim 1, wherein The step of receiving the configuration for the candidate cell includes: receiving a plurality of configurations for candidate cells for the cell handover from the network, the plurality of configurations for candidate cells including the configuration for the candidate cell, Each of the plurality of configurations is associated with a corresponding candidate cell, and each of the plurality of configurations includes: a candidate configuration index for the configuration of the corresponding candidate cell; and a plurality of resource configurations associated with the candidate configuration index, and Each of the plurality of resource configurations includes a resource configuration index of the corresponding resource configuration.

3. The method according to claim 1, wherein The cell switching command includes: a candidate configuration index for the configuration of the candidate cell; and A resource configuration index of the resource configuration among the multiple resource configurations associated with the candidate configuration index.

4. The method according to claim 1, further comprising the steps of: performing a layer 1 (L1) measurement on the candidate cell to obtain an L1 measurement result for the candidate cell; as well as sending an L1 measurement report including the L1 measurement result to the network, The step of receiving the cell handover command includes receiving the cell handover command after sending the L1 measurement report to the network.

5. The method according to claim 2, further comprising the steps of: identifying, among the plurality of configurations for the candidate cell, the configuration for the candidate cell having a candidate configuration index that matches the candidate configuration index in the cell handover command; as well as Among the multiple resource configurations in the configurations for the candidate cell, the resource configuration having a resource configuration index matching the resource configuration index in the cell handover command is identified.

6. The method according to claim 2, wherein: receiving the plurality of configurations for the candidate cells via radio resource control (RRC) signaling, and The cell switching command is received via medium access control (MAC) control element (CE) signaling.

7. The method according to claim 1, wherein The cell handover includes Layer 1 (L1) / Layer 2 (L2) triggered mobility (LTM), and The cell switching command includes an LTM command.

8. The method according to claim 1, wherein The multiple resource configurations include at least one of the following: A set of physical channel configurations; A set of downlink (DL) bandwidth part (BWP) configurations; A set of UL BWP configurations; A set of secondary cell (SCell) states; A set of timing advance (TA) values; A set of Transmission Configuration Indication (TCI) states; a set of indications for at least one of a Packet Data Convergence Protocol (PDCP) resumption, a Radio Link Control (RLC) re-establishment, or a Medium Access Control (MAC) reset; A set of synchronization signal blocks (SSB index; a set of channel state information (CSI)-reference signal (RS) indices; or An indication of whether the UE performs random access when performing the cell handover.

9. The method according to claim 8, wherein The set of physical channel configurations includes at least one of the following: a set of physical uplink control channel (PUCCH) configurations; A set of physical uplink shared channel (PUSCH) configurations; A set of physical downlink control channel (PDCCH) configurations; a set of Physical Downlink Shared Channel (PDSCH) configurations; or A set of physical random access channel (PRACH) configurations.

10. The method according to claim 1, wherein The step of performing the cell switching includes: applying the configuration for the candidate cell; and sending one or more uplink (UL) signals to the candidate cell, The one or more UL signals include a UL signal sent based on the resource configuration notified by the cell switching command.

11. The method according to claim 10, wherein: The cell switching includes cell switching based on a random access channel (RACH), and The one or more UL signals include at least one of the following: A random access preamble sent based on a physical random access channel (PRACH) configuration notified by the cell handover command; or A radio resource control (RRC) reconfiguration complete message is sent based on a UL grant provided by a random access response to the random access preamble.

12. The method according to claim 10, wherein: The cell switching includes a RACH-less cell switching, and The one or more UL signals include at least one of the following: a scheduling request sent based on a physical uplink control channel (PUCCH) configuration notified by the cell handover command; a Layer 1 (L1) / Layer 2 (L2) triggered mobility (LTM) completion medium access control (MAC) control element (CE) transmitted based on the first physical uplink shared channel (PUSCH) configuration notified by the cell handover command; or A radio resource control (RRC) reconfiguration complete message is sent based on the second PUSCH configuration notified by the cell handover command.

13. The method according to claims 1 to 12, wherein: The UE communicates with at least one of a mobile device, a network, or an autonomous vehicle.

14. A user equipment (UE) configured to operate in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; as well as at least one memory operatively coupled to the at least one processor and storing instructions that, upon execution by the at least one processor, perform operations comprising: receiving, from a network, a configuration for a candidate cell for cell handover, wherein the configuration for the candidate cell includes a plurality of resource configurations for the candidate cell; receiving a cell handover command for the candidate cell from the network, wherein the cell handover command notifies a resource configuration among the plurality of resource configurations for the candidate cell; and The cell handover to the candidate cell is performed based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

15. The UE according to claim 14, wherein: The UE is arranged to implement the method according to one of claims 2 to 13.

16. A network node configured to operate in a wireless communication system, the network node comprising: at least one transceiver; at least one processor; as well as at least one memory operatively coupled to the at least one processor and storing instructions that, upon execution by the at least one processor, perform operations comprising: sending a configuration for a candidate cell for cell handover to a user equipment (UE), wherein the configuration for the candidate cell includes a plurality of resource configurations for the candidate cell; and sending a cell handover command for the candidate cell to the UE, wherein the cell handover command notifies a resource configuration among the multiple resource configurations for the candidate cell, The cell handover to the candidate cell is performed based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

17. A method performed by a network node configured to operate in a wireless communication system, the method comprising: sending a configuration for a candidate cell for cell handover to a user equipment (UE), wherein the configuration for the candidate cell includes a plurality of resource configurations for the candidate cell; and sending a cell handover command for the candidate cell to the UE, wherein the cell handover command notifies a resource configuration among the multiple resource configurations for the candidate cell, The cell handover to the candidate cell is performed based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

18. The method according to claim 17, wherein The UE is arranged to implement the method according to one of claims 1 to 13.

19. A device adapted to operate in a wireless communication system, the device comprising: at least one processor; as well as at least one memory operatively coupled to the at least one processor and storing instructions that, upon execution by the at least one processor, perform operations comprising: receiving, from a network, a configuration for a candidate cell for cell handover, wherein the configuration for the candidate cell includes a plurality of resource configurations for the candidate cell; receiving a cell handover command for the candidate cell from the network, wherein the cell handover command notifies a resource configuration among the plurality of resource configurations for the candidate cell; and The cell handover to the candidate cell is performed based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

20. A non-transitory computer readable medium (CRM) having program code stored thereon implementing instructions, the instructions, upon being executed by at least one processor, performing operations comprising: receiving, from a network, a configuration for a candidate cell for cell handover, wherein the configuration for the candidate cell includes a plurality of resource configurations for the candidate cell; receiving a cell handover command for the candidate cell from the network, wherein the cell handover command notifies a resource configuration among the plurality of resource configurations for the candidate cell; and The cell handover to the candidate cell is performed based on the resource configuration notified by the cell handover command in the configuration for the candidate cell.

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