Methods and apparatus of UE-initiated mobility
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-06
- Publication Date
- 2026-08-13
Smart Images
Figure CN2025075941_13082026_PF_FP_ABST
Abstract
Description
METHODS AND APPARATUS OF UE-INITIATED MOBILITYFIELD
[0001] The present disclosure relates generally to communication systems, and more particularly, the method and apparatus to support UE-initiated mobility.BACKGROUND
[0002] In the evolution of wireless communication systems, UE-initiated mobility has emerged as a critical enabler for improving network performance and user experience. Historically, network-controlled mobility management has been the predominant approach, where the network dictates when and how a UE should perform a handover. However, this approach often introduces latency and inefficiency, as the network may not always have real-time visibility into the UE's radio environment. UE-initiated mobility, on the other hand, empowers the UE to make autonomous decisions based on its local measurements and conditions, offering several advantages.
[0003] UE-initiated mobility enhances reliability by enabling the UE to proactively perform a handover when specific conditions are met. This proactive approach allows the UE to react quickly to deteriorating radio conditions, preventing the situation from worsening to a point where a handover might fail. Additionally, by eliminating the need for a handover command from the network, UE-initiated mobility reduces the risk of handover failures caused by signaling delays or losses. This is particularly beneficial in scenarios where low latency and high reliability are critical, such as in mission-critical applications or real-time communication services.
[0004] UE-initiated mobility improves UE autonomy and flexibility. By allowing the UE to independently decide which candidate cell to perform a handover to, based on predefined conditions and pre-configured candidate cell configurations, the UE can make more accurate and context-aware decisions. The UE's ability to leverage its detailed local radio environment measurements enables it to detect subtle changes in network conditions that may not be captured in traditional measurement reports. This capability not only enhances the efficiency of the handover process but also reduces the overhead associated with frequent signaling between the UE and the network.
[0005] In the context of 6G, the importance of UE-initiated mobility becomes even more pronounced. 6G networks are expected to support ultra-high-speed mobility, ultra-low latency, and ultra-wide coverage, while maintaining seamless connectivity in diverse and dynamic environments, such as dense urban areas, high-speed transportation, and industrial IoT applications. These demanding requirements necessitate a more intelligent and adaptive mobility management mechanism. UE-initiated mobility, with its inherent advantages of reduced latency, enhanced reliability, and improved resource utilization, is well-suited to meet these challenges. By enabling the UE to take a more active role in mobility management, 6G networks can achieve higher performance, better user experience, and more efficient operation in complex and rapidly changing wireless environments.
[0006] In this invention, apparatus and mechanisms are sought to support a unified UE-initiated mobility procedure.SUMMARY
[0007] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
[0008] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The cell switch decision is be triggered by UE upon occurrence of a predetermined event. UE receives the initial configuration from network to start UE initiate mobility evaluation. The trigger of cell switch decision means UE determines the target cell according to the condition provided in the initial configuration. In one embodiment, cell switch preparation can be performed before cell switch. In different embodiments, the cell switch preparation can be triggered by UE or network. In different embodiments, the cell switch preparation includes DL synchronization and / or UL synchronization and / or ASN. 1 decoding of candidate configuration (s) . In different embodiments, UE receives a signaling from network for cell switch preparation, which includes one or more of the TCI state activation / deactivation information and / or TA value and / or UL grant (resource) for the first transmission and / or the CFRA information of candidate cell (s) . In one embodiments, the TA value maintenance mechanism is introduced for the TA value of candidate cell before cell switch. In different embodiments, the TCI states are pre-activated or pre-defined in the DL synchronization or initial configuration. UE selects one of the indicated TCI state (beam) to send the first UL transmission.
[0009] The UE-initiated mobility may also be referred to as a UE-initiated handover, an conditional handover, or by other terminology used in the art. The "candidate cell" used in the art refer to the candidate cell before cell switch decision is made. The "target cell" used in the art refer to the target cell after cell switch decision is made.
[0010] The invention is not limited to 5G NR, it may also apply to other communication systems, such as 6G or further-generation communication systems.
[0011] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 illustrates an schematic system diagram illustrating an exemplary wireless communication network in accordance with embodiments of the current invention.
[0013] Figure 2 illustrates an exemplary wireless communication system with centralization of the upper layers of the radio stacks in accordance with embodiments of the current invention.
[0014] Figure 3 illustrates an exemplary overall flow for UE to perform UE-initiate mobility in accordance with embodiments of the current invention.
[0015] Figure 4 illustrates an exemplary process for initial configuration of UE-initiated mobility in accordance with embodiments of the current invention.
[0016] Figure 5 illustrates an exemplary process for cell switch preparation of UE-initiated mobility in accordance with embodiments of the current invention.
[0017] Figure 6 illustrates exemplary processes for DL synchronization of UE-initiated mobility in accordance with embodiments of the current invention.
[0018] Figure 7 illustrates exemplary processes for UL synchronization of UE-initiated mobility in accordance with embodiments of the current invention.
[0019] Figure 8 illustrates exemplary signaling for Cell switch preparation of UE-initiated mobility in accordance with embodiments of the current invention.
[0020] Figure 9 illustrates exemplary schematic system diagram for UE to select the target beam during UE-initiated cell switch in accordance with embodiments of the current invention.DETAILED DESCRIPTION
[0021] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.
[0022] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
[0023] Aspects of the present disclosure provide methods, apparatus, processing systems, and computer readable mediums for NR (new radio access technology, or 5G technology) , 6G or other radio access technology. NR or 6G may support various wireless communication services. These services may have different quality of service (QoS) requirements e.g. latency and reliability requirements.
[0024] Figure 1 illustrates a schematic system diagram illustrating an exemplary wireless network in accordance with embodiments of the current invention. Wireless system includes one or more fixed base infrastructure units forming a network distributed over a geographical region. The base unit may also be referred to as an access point, an access terminal, a base station, a Node-B, an eNode-B, a gNB, a 6G base station, or by other terminology used in the art. As an example, base stations serve a number of mobile stations within a serving area, for example, a cell, or within a cell sector. In some systems, one or more base stations are coupled to a controller forming an access network that is coupled to one or more core networks. gNB 1 and gNB 2 (or 6G base station) are base stations in NR (or in 6G) , the serving area of which may or may not overlap with each other. As an example, UE 1 or mobile station is only in the service area of gNB 1 and connected with gNB1. UE1 is connected with gNB1 only, gNB1 is connected with gNB 1 and 2 via Xn interface. UE2 is in the overlapping service area of gNB1 and gNB2.
[0025] Figure 1 further illustrates simplified block diagrams for UE2 and gNB2, respectively. UE has an antenna, which transmits and receives radio signals. A RF transceiver, coupled with the antenna, receives RF signals from antenna, converts them to baseband signal, and sends them to processor. In one embodiment, the RF transceiver may comprise two RF modules (not shown) . A first RF module is used for transmitting and receiving on one frequency band, and the other RF module is used for different frequency bands transmitting and receiving which is different from the first transmitting and receiving. RF transceiver also converts received baseband signals from processor, converts them to RF signals, and sends out to antenna. Processor processes the received baseband signals and invokes different functional modules to perform features in UE. Memory stores program instructions and data to control the operations of mobile station. UE also includes multiple function modules that carry out different tasks in accordance with embodiments of the current invention.
[0026] An RRC State controller, which controls UE RRC state according to network’s command and UE conditions. RRC supports the following states, RRC_IDLE, RRC_CONNECTED and RRC_INACTIVE, or other RRC states defined in other communication systems.
[0027] A DRB controller, which controls to establish / add, reconfigure / modify and release / remove a DRB based on different sets of conditions for DRB establishment, reconfiguration and release. A protocol stack controller, which manage to add, modify or remove the protocol stack for the DRB. The protocol Stack includes SDAP, PDCP, RLC, MAC and PHY layers. In different communication system, such as 6G, the protocol stack may include other protocol layers or remove some layers. The invention is not limited by this.
[0028] In one embodiment, the SDAP layer supports the functions of transfer of data, mapping between a QoS flow and a DRB, marking QoS flow ID, reflective QoS flow to DRB mapping for the UL SDAP data PDUs, etc.
[0029] In one embodiment, the PDCP layer supports the functions of transfer of data, maintenance of PDCP SN, header compression and decompression using the ROHC protocol, ciphering and deciphering, integrity protection and integrity verification, timer-based SDU discard, routing for split bearer, duplication, re-ordering and in-order delivery; out of order delivery and duplication discarding.
[0030] In one embodiment, the RLC layer supports the functions of error correction through ARQ, segmentation and reassembly, re-segmentation, duplication detection, re-establishment, etc. In one embodiment, a new procedure for RLC reconfiguration is performed, which can reconfigure the RLC entity to be associated to one or two logical channels.
[0031] In one embodiment, the MAC layer supports the following functions: mapping between logical channels and transport channels, multiplexing / demultiplexing, HARQ, radio resource selection, etc.
[0032] Similarly, gNB2 has an antenna, which transmits and receives radio signals. A RF transceiver, coupled with the antenna, receives RF signals from antenna, converts them to baseband signals, and sends them to the processor. RF transceiver also converts received baseband signals from the processor, converts them to RF signals, and sends out to antenna. The processor processes the received baseband signals and invokes different functional modules to perform features in gNB2. Memory stores program instructions and data to control the operations of gNB2. gNB2 also includes multiple function modules that carry out different tasks in accordance with embodiments of the current invention.
[0033] A RRC State controller, which performs access control for the UE.
[0034] Figure 2 illustrates an exemplary wireless communication system with centralization of the upper layers of the NR radio stacks in accordance with embodiments of the current invention. Different protocol split options between Central Unit and lower layers of gNB nodes may be possible. The functional split between the Central Unit and lower layers of gNB nodes may depend on the transport layer. Low performance transport between the Central Unit and lower layers of gNB nodes can enable the higher protocol layers of the NR radio stacks to be supported in the Central Unit, since the higher protocol layers have lower performance requirements on the transport layer in terms of bandwidth, delay, synchronization and jitter. In one embodiment, SDAP and PDCP layer are located in the central unit, while RLC, MAC and PHY layers are located in the distributed unit. In other embodiments, the layers may be different in central unit or distributed unit, according to the layers defined in different communication systems, such as 6G.
[0035] Figure 3 illustrates an exemplary overall flow for UE to perform UE-initiate mobility in accordance with embodiments of the current invention. To begin UE-initiate mobility, UE receives the initial configuration from network. In one embodiment, UE performs cell switch preparation toward candidate cell (s) , based on network indication or the triggering of certain pre-defined conditions. In one embodiments, UE monitor the condition for cell switch preparation first, and then monitor the cell switch decision condition. In another embodiment, UE monitor the condition for cell switch preparation the cell switch decision condition simultaneously, and the cell switch preparation can be skipped if switch decision condition triggered first. In one embodiment, the cell switch preparation condition is not provided in the configuration. UE perform cell switch toward target cell when triggering of certain pre-defined conditions for cell switch decision is met. In one embodiment, UE monitors the next cell switch triggering condition and / or cell switch preparation condition after one UE-initiated mobility is completed without extra network signaling. In different embodiments, UE receives candidate cells adding / removal signaling to add / remove candidate cell (s) from the candidate cell list.
[0036] Figure 4 illustrates an exemplary process for initial configuration of UE-initiated mobility in accordance with embodiments of the current invention. UE receives an RRC signaling from network for UE-initiate mobility configuration. In different embodiments, the configuration includes candidate cell list; configuration for each candidate cells, the triggering event for the cell switch preparation and decision for each candidate cells (including triggering types, TTT, hysteresis, leaving condition, etc. ) ; the measurement configurations (including parameters for filtering, beam consolidation, L1 or L3 measurement) ; the default TCI state (s) ; the reporting container type of measurement (including RRC signaling, MAC-CE, UCI or other dedicated uplink signaling) ; the reporting interval; the reporting type (including periodic, aperiodic, semi-persistent, event triggered) ; the maximum reporting size, etc. In different embodiments, the trigger events for each candidate cells can be configured per candidate cell as target cell, or per candidate cell as source cell, or per cell pairs as candidate cell to another candidate cell.
[0037] The UE send configuration complete to the network for confirmation. After UE receives the UE-initiate mobility configuration from network, UE performs measurement and report according to the configuration in the UE-initiate mobility configuration. The UE-initiate mobility configuration may also be referred to as a RRCReconfiguration, or by other terminology used in the art. The Configuration complete message may also be referred to as a RRCReconfigurationComplete, or by other terminology used in the art.
[0038] Figure 5 illustrates an exemplary process for cell switch preparation of UE-initiated mobility in accordance with embodiments of the current invention. In different embodiments, UE performs cell switch preparation toward candidate cell upon occurrence of a predetermined event or indicated by the network. In different embodiments, the cell switch preparation includes DL synchronization and / or UL synchronization and / or ASN. 1 decoding of candidate configuration (s) . Some of the procedure can be skipped. In different embodiments, the DL synchronization and / or UL synchronization and / or ASN. 1 decoding of candidate configuration (s) can be performed in parallel or in series. In one embodiment, UE informs the network of the cell switch preparation via measurement report or other signaling.
[0039] Figure 6 illustrates exemplary processes for DL synchronization of UE-initiated mobility in accordance with embodiments of the current invention. In one embodiment, UE performs DL synchronization by measuring the Downlink RS of candidate cells to track the TCI states of candidate cell (s) . UE may informs the network of the TCI states it selects via measurement report or other signaling. In another embodiment, UE receives an activation / deactivation indication of candidate TCI states from network. UE tracks the indicated activated candidate TCI states and untrack the indicated deactivated candidate TCI states. In one embodiment, the DL synchronization is triggered by UE upon occurrence of a predetermined event. In one embodiment, the UE sends a signaling to network to request the indication of activation / deactivation for candidate TCI states.
[0040] Figure 7 illustrates exemplary processes for UL synchronization of UE-initiated mobility in accordance with embodiments of the current invention. In one embodiment, UE performs UL synchronization by calculating the TA value of candidate cell from the time difference of two DL RS of candidate / serving cells. In another embodiment, UE receives TA value of candidate cell (s) . In one embodiment, UE and / or network starts an TA timer for one candidate cell when the TA value is received by UE, and the TA value is considered to be invalid when TA timer expires. In one embodiment, UE sends RACH preamble toward candidate cell to request / refresh the TA value of candidate cell. For example, the preamble is sent when UE receives the PDCCH order from network, or the predetermined event condition for UL sync is triggered, or the TA timer expires. In another embodiment, UE receives an PDCCH order or other indication from network for TA refresh request. For example, UE sends a signaling to network to request to the network to send PDCCH order upon a predetermined event condition for UL sync is triggered, or the TA timer expires. In one embodiment, UE sends a signaling to network to request TA for candidate cell, and the signaling may be an existing signaling or a new signaling other than preamble .
[0041] Figure 8 illustrates exemplary signaling for Cell switch preparation of UE-initiated mobility in accordance with embodiments of the current invention. In different embodiment, the signaling for Cell switch preparation contains one or more of the information including: TCI state activation / deactivation information of candidate cell (s) ; TA value of candidate cell (s) ; UL grant (resource) for the first UL transmission of candidate cell (s) ; CFRA information of candidate cell (s) used in random access procedure. In different embodiment, the signaling may contains the information of one or more candidate cells. In different embodiments, the Cell switch preparation signaling is an RRC signaling, an MAC-CE or other dedicated downlink signaling, which is delivered to UE via serving cell.
[0042] Figure 9 illustrates exemplary schematic system diagram for UE to select the target beam during UE-initiated cell switch in accordance with embodiments of the current invention. For the target cell, in one embodiment, some beams have been indicated and activated during DL synchronization, while others have not. Those beams are tracked by UE. In one embodiment, UE prioritizes the target beam that have been indicated and tracked in the DL synchronization during cell switch preparation and select the one with the best measurement result among them.
[0043] In another embodiment, some beams have been indicated as default beam in initial configuration for one candidate cell. In one embodiment, UE selects the target beam which meet certain pre-defined threshold from a default TCI state list provided in initial configuration if none of the DL synced beams meets a certain pre-configured threshold. In one embodiment, UE informs network about the selected beam. In one embodiment, the network sends RSs for each indicated TCI state in downlink and monitor the uplink resources for each indicated TCI state until cell switch complete or the TCI states are deactivated by the network.
[0044] Throughout this specification, the terms "Initial configuration " , ” Cell switch preparation” , "UL synchronization" , "DL synchronization " , "Cell switch decision" and "Cell switch execution" have been used to describe various aspects of the disclosed technology. It should be understood that these terms, as well as any other terminology used herein, are not intended to be limiting. The disclosed embodiments may be referred to by other names or terms in various sources of material, but such alternative names or terms shall be understood to encompass the corresponding elements described herein. Accordingly, any equivalent terms or nomenclature that convey the same or substantially similar meaning as the terms used in this disclosure are intended to fall within the scope of the claims of this patent, even if such terms are not explicitly used in the claims. The use of different terminology or nomenclature that conveys the same functional or structural characteristics as the elements described herein is intended to be within the scope of the present invention.
[0045] It is understood that the specific order or hierarchy of blocks in the processes / flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes / flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
[0046] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C,” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and / or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”
[0047] While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.
Claims
1.A method for UE to support UE initiated mobility, comprising the steps of:receiving initial configuration from network with candidate cell (s) information; andtriggering cell switch decision upon occurrence of a predetermined event and perform cell switch toward target cell.2.The method of claim 1, wherein the predetermined event of cell switch preparation and / or cell switch decision is configured by the initial configuration.3.The method of claim 2, wherein the predetermined event is configured per candidate cell as target cell, or per candidate cell as source cell, or per candidate cell to other candidate cell pairs.4.The method of claim 1, further comprising UE sends measurement report to the network.5.The method of claim 4, wherein the measurement report is send via RRC signaling, MAC-CE, UCI or other dedicated uplink signaling.6.The method of claim 4, further comprising UE inform network its decision of cell switch decision and / or cell switch preparation in the signaling of measurement report.7.The method of claim 1, further comprising UE performs cell switch preparation toward candidate cell upon occurrence of predetermined events or indicated by the network, wherein the cell switch preparation includes DL synchronization and / or UL synchronization and / or ASN. 1 decoding of candidate configuration (s) .8.The method of claim 7, further comprising UE measures the Downlink RS to track the TCI states from candidate cell (s) for DL synchronization.9.The method of claim 7, further comprising UE receives the signaling from network with activation / deactivation information of candidate TCI states to start to track the candidate TCI states from candidate cell for DL synchronization.10.The method of claim 7, further comprising UE receives TA value of candidate cell from network for UL synchronization.11.The method of claim 10, wherein a TA timer is start by UE when receiving the TA value for validity calculation, and the TA value is considered to be invalid when TA timer expires.12.The method of claim 10, further comprising UE sends RACH preamble toward candidate cell to request / refresh the TA value of candidate cell.13.The method of claim 12, wherein the preamble is sent when UE receives the PDCCH order from network, or the predetermined event condition for UL sync is triggered, or the TA timer expires.14.The method of claim 10, further comprising UE receives an PDCCH order or other indication from network for TA refresh request.15.The method of claim 14, further comprising UE request to the network to send PDCCH order upon a predetermined event condition for UL sync is triggered, or the TA timer expires.16.The method of claim 7, further comprising UE calculates the TA value of candidate cell by the time difference of two DL RS of candidate / serving cells for UL synchronization.17.The method of claim 7, further comprising UE receives a signaling from network for cell switch preparation.18.The method of claim 17, wherein the signaling is a MAC-CE or other dedicated downlink signaling, which is delivered to UE via serving cell.19.The method of claim 17, wherein the signaling delivers the TCI state activation / deactivation indication and / or TA value and / or UL grant (resource) for the first transmission of candidate cell (s) .20.The method of claim 17, wherein the CFRA information of candidate cell (s) is included in the signaling if the UL synchronization is not performed.21.The method of claim 7, wherein the predetermined events for DL synchronization and / or UL synchronization and / or ASN. 1 decoding of candidate configuration (s) are separate or the same condition.22.The method of claim 1, further comprising UE selects the target beam of target cell when cell switch decision is triggered.23.The method of claim 22, further comprising UE prioritizes the target beam that have been activated in the DL synchronization during cell switch preparation and select the one with the best measurement result among them.24.The method of claim 22, further comprising UE selects the target beam which meet certain pre-defined threshold from a default TCI state list provided in initial configuration if none of the DL synced beams for target cell meets a certain pre-configured threshold.25.The method of claim 22, further comprising UE sends the first UL transmission via the selected target beam with UL resources which is provided to the UE during the initial configuration or during cell switch preparation.26.The method of claim 1, further comprising UE monitor the next cell switch triggering condition and / or cell switch preparation condition after one UE initiated mobility is completed.27.The method of claim 1, further comprising UE adds new candidate cells into candidate cell list by receiving a candidate cell adding signaling from network.28.The method of claim 1, further comprising UE removes part / all candidate cells from the candidate cell list by receiving a candidate cell removal signaling from network.29.A method for network to support UE initiated mobility, comprising the steps of:sending initial configuration to UE with candidate cell configurations;monitoring the uplink resources of candidate cell (s) to prepare for the cell switch triggered by UE.30.The method of claim 29, further comprising network sends RSs for each indicated TCI state in downlink and monitor the uplink resources until cell switch complete or the TCI state is deactivated by the network.31.The method of claim 29, further comprising network send one or more cell switch preparation signaling to UE to provide the information of TCI state activation / deactivation and / or TA value and / or UL grant (resource) for the first transmission of candidate cell (s) and / or the CFRA resource of Random access during cell switch.32.The method of claim 29, further comprising network starts a TA timer a TA value for candidate cell is received by UE.33.The method of claim 32, further comprising network sends PDCCH order to UE if the TA timer expires.34.The method of claim 32, further comprising network sends the latest TA value of candidate cell to UE if the TA timer expires.35.The method of claim 29, further comprising network provide pre-defined TCI state list provided in initial configuration.