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EP-4044669-B1 - CELL CONDITION UPDATING METHOD, USER EQUIPMENT AND COMPUTER-READABLE STORAGE MEDIUM

EP4044669B1EP 4044669 B1EP4044669 B1EP 4044669B1EP-4044669-B1

Inventors

  • DENG, Yun

Dates

Publication Date
20260506
Application Date
20200727

Claims (13)

  1. A cell conditional change method, performed by a User Equipment, UE, and comprising: based on a candidate Primary Secondary Cell, PSCell, meeting a PSCell change trigger condition, performing (S101) a PSCell change, wherein the candidate PSCell corresponds to a candidate Secondary Node, SN; characterized in that the method further comprises: during the PSCell change, determining whether a preset condition for terminating the PSCell change is met, wherein the preset condition comprises any of the following: a Radio Resource Control, RRC, signaling received (S102) from a Master Node, MN, being an RRC signaling of a preset type (S103), wherein the RRC signaling of the preset type comprises an RRC signaling for Primary Cell, PCell, change, an RRC signaling for PSCell change, or a release signaling for PSCell; and based on the preset condition for terminating the PSCell change being met, terminating (S104) the PSCell change.
  2. The method according to claim 1, wherein following receiving the RRC signaling for PCell change, the method further comprises: based on detecting that the RRC signaling for PCell change does not comprise Secondary Cell Group, SCG, information, deleting SCG information corresponding to a source SN and SCG information corresponding to the candidate SN.
  3. The method according to claim 1, wherein following receiving the RRC signaling for PCell change, the method further comprises: based on detecting that the RRC signaling for PCell change comprises new SCG information, accessing a target SN corresponding to the new SCG information based on the new SCG information.
  4. The method according to claim 3, wherein said accessing a target SN corresponding to the new SCG information based on the new SCG information comprises: based on the target SN adopting a delta signaling mode, generating target configuration information based on SCG information corresponding to a source SN and the new SCG information; and accessing the target SN based on the target configuration information.
  5. The method according to claim 1, wherein following receiving the RRC signaling for PCell change, the method further comprises: based on detecting that the RRC signaling for PCell change comprises source SN information, accessing a source SN by a random access procedure.
  6. The method according to claim 5, wherein following detecting that the RRC signaling for PCell change comprises the source SN information, the method further comprises: saving SCG information corresponding to the candidate SN.
  7. The method according to claim 1, further comprising during the PSCell change, based on detecting that a candidate PCell meets a conditional handover trigger condition, performing a PCell handover, and terminating the PSCell change.
  8. The method according to claim 1, wherein following receiving the RRC signaling for PSCell change from the MN, the method further comprises: accessing a PSCell indicated by the RRC signaling for PSCell change.
  9. The method according to claim 1, wherein following receiving the release signaling for PSCell from the MN, the method further comprises: deleting SCG information corresponding to a source SN and SCG information corresponding to the candidate SN.
  10. The method according to claim 1, wherein following determining that the candidate PSCell meets the PSCell change trigger condition, the method further comprises: transmitting PSCell change information to the MN, wherein the candidate PSCell or a target PSCell that meets the PSCell change trigger condition is indicated in the PSCell change information.
  11. The method according to claim 1, wherein following terminating the PSCell change, the method further comprises: retaining SCG information corresponding to a source SN, and deleting SCG information corresponding to the candidate SN.
  12. A non-volatile or non-transitory computer-readable storage medium having computer instructions stored therein, characterized in that when the computer instructions are executed by a processor associated with a User Equipment, UE, steps of the method of any one of claims 1 to 11 is performed by the UE.
  13. A User Equipment, UE, comprising a memory and a processor, characterized in that the memory has computer instructions stored therein, and when the processor executes the computer instructions, the method of any one of claims 1 to 11 is performed.

Description

TECHNICAL FIELD The present disclosure generally relates to radio communication field, and more particularly, to a cell conditional change method, a User Equipment (UE) and a computer-readable storage medium. BACKGROUND In discussion of 3GPP, a Conditional Handover (CHO) has been introduced. Compared with an existing handover process, a handover command for CHO includes a handover condition (or referred to as a handover trigger condition), such as determining whether signal quality of candidate target cells is higher than that of a serving cell by a predetermined offset. After receiving the handover command, a UE determines whether the handover condition is met. If the handover condition is met, the UE uses configuration parameters of the candidate target cells contained in the handover command to access a target cell, synchronizes with the target cell, and initiates a random access procedure in the target cell. If the handover condition is not met, the UE continues to maintain Radio Resource Control (RRC) connection with a source base station. CHO can be used for Primary Secondary Cell change (PSCell change) and Primary Secondary Cell Addition (PSCell Addition) in dual connectivity. In dual connectivity, a UE keeps connected with two base stations including a Master Node (MN) and a Secondary Mode (SN) (the UE is at least configured with PCell by the MN, and is at least configured with PSCell by the SN), and is capable of simultaneously receiving signaling and data from the two base stations, and simultaneously transmitting signaling and data to the two base stations. When CHO is introduced into PSCell change, the MN may determine one or several candidate PSCells, and a change trigger condition corresponding to each candidate PSCell. It should be noted that, strictly speaking, a PSCell change cannot be regarded as "handover". For a UE in a dual-connectivity state, the MN is responsible for the UE's RRC connection establishment and link management such as handover decision, and the SN is responsible for data transmission. When the SN changes or PSCell varies, it can only be called an SN change or a PSCell change. When PCell varies, it can be called a handover. In this embodiment, PCell change and PSCell change are represented by cell change. For PSCell Change, it may occur within a same SN or between different SNs, and the PSCell change between different SNs may also be referred to as an SN change. The MN transmits a PSCell conditional change request to the SN to which candidate PSCells belong. The PSCell conditional change request includes radio parameters configured by the MN for the UE, for example, ConfigRestrictInfoSCG, as well as UE capability information and radio parameters (sourceConfigSCG) configured by a source SN for the UE. The MN transmits a PSCell conditional change request to the SN to which candidate PSCells belong. The PSCell conditional change request includes radio parameters configured by the MN for the UE, for example, ConfigRestrictInfoSCG, as well as UE capability information and radio parameters (sourceConfigSCG) configured by a source SN for the UE. After receiving the PSCell conditional change request, the candidate SN makes an admission control decision based on information such as cell load, to accept or reject the request. If the request is accepted, the candidate SN configures radio parameters of candidate Secondary Cell Groups (SCG configuration) for the UE, and return acknowledgement information to the MN, where the acknowledgement information carries the SCG configuration configured for the UE. After receiving the acknowledgement message, the MN transmits the SCG configuration, identifiers of the candidate PSCells and a PSCell change trigger condition to the UE via RRC signaling. After receiving the RRC signaling, the UE saves received information and starts to evaluate the candidate PSCells. When the candidate PSCell meets the PSCell change trigger condition, the PSCell change is started. In some solutions, when the UE is in a process of PSCell conditional change, and has started to perform PSCell change, the UE still maintains connection with the MN, and can receive RRC signaling from the MN. However, the RRC signaling issued by the MN may conflict with the current PSCell change. Exiting standards haven't provided a solution for the above scenario. US 2017/0055187 A1 discloses 5G or pre-5G communication systems for supporting higher data transfer rates, following the 4G communication systems, such as LTE. A method for supporting handover with multi-connectivity in a wireless communication system is provided. The method includes sending a measurement report message including information of at least one small base station (eNB) to a macro cell eNB, receiving information of a new small eNB in a target cell from the macro cell eNB based on the measurement report message, and performing a random access procedure with the new small eNB in the target cell based on handover. ZTE,