CN-122028122-A - Method and apparatus for supporting handover

Abstract

According to an embodiment of the disclosure, a method and a device for supporting handover are provided. The method comprises the steps of receiving a message from a control plane entity of a central unit of a destination base station, receiving a data packet from a source base station, and discarding a PDCP service data unit SDU (packet data convergence protocol) containing a PDCP sequence number SN in the received data packet according to an indication of the message. The method can solve the problem of coordination work of the source base station and the target base station in the switching process. In particular, in the case that the source base station and/or the destination base station support the separation of the control plane and the data plane, it is ensured that the source base station central unit control plane entity, the source base station central unit user plane entity, the destination base station central unit control plane entity and/or the destination base station central unit user plane entity can operate in complete coordination.

Inventors

• XU LIXIANG
• WANG HONG
• WANG WEIWAI

Assignees

• 北京三星通信技术研究有限公司
• 三星电子株式会社

Dates

Publication Date

20260512

Application Date

20210108

Priority Date

20200529

Claims (8)

1. 1. A method performed by a source base station in a wireless communication system, comprising: The source base station hub unit user plane CU-UP receives a message about bearer context modification from the source base station hub unit control plane CU-CP, the message including data forwarding information for handover to the evolved universal terrestrial radio access network E-UTRAN, and And the source base station CU-UP forwards the PDCP service data unit SDU which does not comprise the SDAP packet head according to the data forwarding information.
2. 2. The method of claim 1, wherein the data forwarding information comprises data forwarding channel information including a transport layer address and a channel identification.
3. 3. The method of claim 2, wherein the data forwarding information further comprises at least one of a quality of service guaranteed Qos flow list for forwarding data over the data forwarding channel, a data radio bearer DRB identity, and an evolved radio access bearer E-RAB identity.
4. 4. A method performed by a source base station in a wireless communication system, comprising: The source base station central unit control plane CU-CP receives a message about a handover command, the message including an evolved radio access bearer E-RAB identity and data forwarding channel information, and The source base station CU-CP sends a message regarding bearer context modification to the source base station central unit user plane CU-UP, said message comprising data forwarding information for handover to the evolved universal terrestrial radio access network E-UTRAN, And the source base station CU-UP forwards the PDCP service data unit SDU which does not comprise the SDAP packet head according to the data forwarding information.
5. 5. The method of claim 4, further comprising the source base station CU-CP receiving a protocol data unit PDU session to be established, information of one or more quality of service guaranteed Qos flow in the PDU session, and E-RAB identification of the Qos flow map.
6. 6. A method performed by a destination base station in a wireless communication system, comprising: The user plane CU-UP of the central unit of the target base station receives indication information from the control plane CU-CP of the central unit of the target base station, wherein the indication information indicates the PDCP serial number SN of the discarded packet data convergence protocol; The destination base station CU-UP discards PDCP SNs included in the received data packet, and The destination base station CU-UP sends PDCP service data units SDU with PDCP SNs removed to the user equipment UE.
7. 7. The method of claim 6, wherein the data packet comprises a general packet radio service channel protocol user plane GTP-U data packet.
8. 8. An apparatus supporting handover, comprising: a transceiver for transmitting and receiving signals; Processor, and A memory in which instructions executable by the processor are stored, which when executed by the processor, cause the processor to perform the method of any one of claims 1-7.

Description

Method and apparatus for supporting handover The application is a divisional application of an application patent application with the application date of 2021, 1, 8, the application number of 202110024548.X and the application name of 'method and device for supporting switching'. Technical Field The present invention relates to wireless communication technology, and in particular, to a method and apparatus for supporting handover. Background In order to meet the increasing demand for wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or quasi 5G communication systems. Therefore, a 5G or quasi 5G communication system is also referred to as a "super 4G network" or a "LTE-after-system". Wireless communication is one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeds 50 billion and continues to grow rapidly. As smartphones and other mobile data devices (e.g., tablet computers, notebook computers, netbooks, e-book readers, and machine type devices) become increasingly popular among consumers and businesses, the demand for wireless data services is rapidly growing. To meet the high-speed growth of mobile data services and support new applications and deployments, it is important to improve the efficiency and coverage of the wireless interface. The base station may comprise a base station center unit control plane entity and a base station center unit user plane entity. When a UE moves between two base stations, in order to ensure continuity of traffic, handover procedures need to be defined, including intra-system handover such as handover between gnbs and gnbs, handover between a gNB and an eNB connected to 5GC, and inter-system handover such as handover between 5G system (5 GS) and Evolved Packet System (EPS). Disclosure of Invention Technical problem For data forwarding, how the source base station and the destination base station work cooperatively still has a problem. In particular, in the case that the source base station and/or the destination base station support the separation of the control plane and the data plane, it is still a problem how to ensure that the source base station central unit control plane entity, the source base station central unit user plane entity, the destination base station central unit control plane entity and/or the destination base station central unit user plane entity can operate in complete coordination. Technical proposal According to one aspect of an embodiment of the present invention, there is provided a method of supporting handover, comprising receiving a message from a control plane entity of a center unit of a destination base station, receiving a data packet from a source base station, and discarding PDCP service data units SDUs comprising a PDCP sequence number SN of a packet data convergence protocol in the received data packet according to an indication of the message. In one example, the indication of the message includes indication information sent via a bearer context modification request message indicating at least one of full or differential configuration, whether PDCP SNs are reserved, whether PDCP restarts, and whether to discard packets containing PDCP SDUs for PDCP SNs. In one example, discarding PDCP SDUs including PDCP SNs in the received data packet according to the indication of the message includes discarding PDCP SDUs including PDCP SNs in the received data packet when the indication information indicates at least one of full configuration, PDCP SNs are not reserved, PDCP restart, and discarding PDCP SDUs including PDCP SNs. In one example, the indication of the message includes at least one of not receiving PDCP SN status information, not receiving PDCP SN status information of the data radio bearer DRB, not receiving a bearer context modification request message, and not including PDCP SN status information of the DRB in the received bearer context modification request message. In one example, discarding PDCP SDUs containing PDCP SNs includes identifying SDUs to discard based on SNs in general packet radio service GPRS tunneling protocol GTP user plane GTP-U data packets. In one example, the received data packet is sent by the source base station or forwarded by the source base station through the core network. In one example, PDCP SDUs without PDCP SNs in the received data packet are new data. According to another aspect of the embodiment of the invention, a method for supporting handover is provided, which comprises the steps of receiving a handover request message, receiving a Sequence Number (SN) state transition message or a downlink Radio Access Network (RAN) state transition message, and sending a message to a user plane entity of a central unit of a target base station, wherein the user plane entity of the central unit of the target base station discards a PDCP Service Data U