CN107371208B

CN107371208B - Switching method and device

Info

Publication number: CN107371208B
Application number: CN201610322445.0A
Authority: CN
Inventors: 吴昱民
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2016-05-13
Filing date: 2016-05-13
Publication date: 2022-04-29
Anticipated expiration: 2036-05-13
Also published as: WO2017194021A1; CN107371208A

Abstract

The invention provides a switching method and a switching device, wherein the method comprises the following steps: in the process of switching User Equipment (UE) from a source base station to a target base station, the source base station sends timer configuration information and/or an indication of keeping connection with the source base station to the UE, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station; after the timer expires, the source base station releases the connection with the UE. By adopting the technical scheme, the problem of source base station wireless resource waste caused by autonomous release of source base station connection after the UE randomly accesses the target base station in the related technology is solved, and the wireless resource of the source base station is saved in time.

Description

Switching method and device

Technical Field

The present invention relates to the field of wireless communications, and in particular, to a handover method and apparatus.

Background

In the related art, in a current Long Term Evolution (LTE) system, when a User Equipment (User Equipment, UE) wants to switch a target base station, a switching method is adopted, in which a connection is first disconnected from a source base station, and then established at the target base station (i.e., first disconnected and then established, a break-before-make). By adopting the technical scheme, the receiving and sending of the service data are interrupted. Therefore, The group discussed in The third Generation Partnership Project (3 GPP) provides a new scheme for simultaneously maintaining The connection between The source base station and The target base station (i.e., make-before-break) of The UE, and The handover interruption delay on The UE side is reduced by using The make-before-break technical scheme.

Fig. 1 is a flowchart of a method for switching a base station by a UE according to the related art, as shown in fig. 1, the steps are as follows:

step S101, UE reports a Measurement Report (Measurement Report) to a network layer.

In step S102, the Source base station (Source eNB) sends a Handover Request (Handover Request) to the Target base station (Target eNB), (Evolved Node B, eNB for short).

Step S103, the target base station agrees to switch, and replies a switching Request confirmation (Handover Request acknowledgement).

Step S104, the source base station sends a handover command to the UE, that is, an RRC Connection Reconfiguration (RRC Connection Reconfiguration) message and Radio Resource Control (Radio Resource Control, abbreviated as RRC). After receiving the handover command, the UE still maintains the connection with the source base station (or the source base station) without releasing, reserves the configuration of the source base station for maintaining the connection with the source base station, and saves the configuration of the target base station for subsequently establishing the connection with the target base station (or the target base station).

Step S105, the source base station initiates a data forwarding process, sends number state transmission information (5a.sn Status Transfer) to the target base station, and forwards data (5b.data forwarding) to the target base station.

Step S106, the UE initiates a Random Access process at the target while maintaining data transmission with the source base station, and sends a Random Access request to the target base station through a Physical Random Access Channel (PRACH).

Step S107, the target base station replies a Random Access Response (RAR) to the UE. After receiving the response, the UE disconnects from the source base station, and rebuilds its layer 2(layer-2) entity by applying the configuration of the target base station received in S104.

In step S108, the UE transmits RRC Connection configuration Complete information (RRC Connection Reconfiguration Complete) to the target base station.

Step S109, the target base station instructs the source base station to Release the air interface connection with the UE, that is, a UE Context Release (UE Context Release) message.

Fig. 2 is a structural diagram of a layer 2(layer-2) entity of a UE according to the related art, as shown in fig. 2, the entity including: packet Data Convergence Protocol (PDCP); radio Link Control (RLC for short); medium Access Control (MAC) for short.

In the related art, the failure in the handover procedure includes the following two cases, one is a radio link failure: the following 3 seed types were included: 1) physical layer desynchronization; 2) random access of the MAC layer fails; 3) an indication of the maximum number of retransmissions reached by the RLC layer. Another case of handover failure is that the handover is not successfully completed within a specified time.

Aiming at the problem of the radio resource waste of a source base station caused by the autonomous release of the connection of the source base station after the UE randomly accesses to a target base station in the related art, no effective solution is provided at present.

Disclosure of Invention

The embodiment of the invention provides a switching method and a switching device, which are used for at least solving the problem of radio resource waste of a source base station caused by autonomous release of source base station connection after UE randomly accesses a target base station in the related technology.

According to an embodiment of the present invention, there is provided a handover method including: in the process of switching User Equipment (UE) from a source base station to a target base station, the source base station sends timer configuration information and/or an indication of keeping connection with the source base station to the UE, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station; after the timer expires, the source base station releases the connection with the UE.

Optionally, the source base station sends a handover command to the UE, where the handover command carries the timer configuration information and/or an indication of maintaining connection with the source base station, and the handover command is used to indicate that the UE is handed over from the source base station to a target base station.

Optionally, after the source base station sends the handover command to the UE, the source base station receives notification information issued by the target base station, where the notification information is used to notify the source base station to release the connection with the UE; and the source base station informs the UE to release the connection with the source base station.

Optionally, before the source base station sends the timer configuration information and/or the indication of maintaining the connection with the source base station to the UE, the source base station sends the timer configuration information and/or the indication of maintaining the connection with the source base station to the target base station; and the source base station receives reply information of the target base station, wherein the reply information is used for indicating that the target base station receives the timer configuration information and/or an indication of keeping connection with the source base station.

Optionally, before the timer expires and/or before the UE releases the connection with the source base station, the source base station maintains the connection with the UE through the data radio bearer DRB.

According to an embodiment of the present invention, there is provided a handover method including: in the process of switching User Equipment (UE) from a source base station to a target base station, the target base station receives timer configuration information sent by the source base station and/or an instruction for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station; before the timer is overtime and/or before the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB; and after the timer is overtime and/or the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB and the DRB.

Optionally, before the target base station receives the timer configuration information sent by the source base station and/or the indication of maintaining the connection with the source base station, the method further includes: the target base station sends a random access response to the UE; the target base station receives a control plane signaling sent by the UE, wherein the control plane signaling comprises: RRC connection reconfiguration complete message; and the target base station informs the source base station of releasing the connection with the UE, and the target base station informs the UE of releasing the connection with the source base station.

According to an embodiment of the present invention, there is provided a handover method including: in the process of switching User Equipment (UE) from a source base station to a target base station, the UE receives timer configuration information sent by the source base station and/or an instruction for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station; after the timer expires, the UE releases the connection with the source base station.

Optionally, the UE receives a handover command sent by the source base station, where the handover command carries the timer configuration information and/or an indication of maintaining connection with the source base station, and the handover command is used to indicate that the UE is handed over from the source base station to a target base station.

Optionally, before the timer expires and/or before the UE releases the connection with the source base station, the UE maintains the connection with the source base station through the data radio bearer DRB.

Optionally, after the UE receives the handover command sent by the source base station, the UE receives a random access response of the target base station, and the UE reconfigures the signaling radio bearer SRB according to the target base station configuration information in the handover command.

Optionally, after the UE reconfigures the SRB, the UE establishes an independent MAC entity for the SRB, or the SRB and the DRB of the UE share the same MAC entity.

Optionally, when the SRB and the DRB share the same MAC entity, the uplink grant information received by the UE from the target base station is used for data transmission of the SRB, and the uplink grant information received by the UE from the source base station is used for data transmission of the DRB; the buffer status report BSR triggered and reported to the target base station by the UE only includes buffer data of the SRB, and the buffer status report BSR triggered and reported to the source base station by the UE only includes buffer data of the DRB.

Optionally, the UE sends a control plane signaling to the target base station, where the control plane signaling includes: RRC connection reconfiguration complete message; the UE receives a notification message of a target base station or a source base station, wherein the notification message is used for notifying the UE to release the connection with the source base station.

Optionally, after the UE receives the random access response of the target base station, the method further includes: before the timer is overtime and/or before the UE releases the connection with the source base station, the UE transmits data with the target base station through the SRB; and after the timer is overtime and/or the UE releases the connection with the source base station, the UE carries out data transmission with the target base station through the SRB and the DRB.

Optionally, the method further includes: and after the timer is overtime, the UE reconfigures a Radio Bearer (RB) according to the target base station configuration information in the switching command.

Optionally, before the UE reconfigures the RB, the method further includes: under the condition that the SRB and the DRB of the UE adopt the same MAC entity, the UE adopts the target base station configuration information to reconfigure the layer2 entities of the DRB and the SRB; under the condition that the SRB and the DRB of the UE adopt different MAC entities, the UE adopts the target base station configuration information to reconstruct a layer2 entity corresponding to the DRB; and after releasing the MAC entity corresponding to the SRB, the UE reconfigures the SRB into the MAC entity which is the same as the DRB, or after releasing the layer2 entity corresponding to the SRB, the UE reconstructs the SRB into the MAC entity which is the same as the DRB.

Optionally, after the UE reconfigures the RB, the method further includes: and triggering and reporting the BSR of the UE, wherein the BSR comprises data of the DRB and the SRB, and the uplink authorization of the target base station received by the UE can be used for sending the data of the DRB and the SRB at the same time.

Optionally, after the UE receives the handover command sent by the source base station, the method further includes: the UE establishes connection with a target base station by using the configuration information of the target base station, and under the condition that the connection with the target base station fails, the UE keeps the connection with a source base station and releases the configuration information of the target base station.

Optionally, the indication information of the connection establishment failure includes one of the following types: the handover fails; a random access failure; physical layer RLM detection failure; the RLC retransmission fails.

According to another embodiment of the present invention, there is provided a handover apparatus applied to a source base station, including: a sending module, configured to send, to a user equipment UE, timer configuration information and/or an indication of maintaining connection with a source base station, in a process of switching the UE from the source base station to a target base station, where the timer configuration information is used to configure a timer for a connection duration between the UE and the source base station; a first releasing module, configured to release, by the source base station, the connection with the UE after the timer expires.

According to another embodiment of the present invention, there is provided a handover apparatus applied to a target base station, including: a first receiving module, configured to receive, by a user equipment UE, timer configuration information sent by a source base station and/or an indication of maintaining connection with the source base station in a handover process from the source base station to a target base station, where the timer configuration information is used to configure a timer for a connection duration between the UE and the source base station; a communication module, configured to communicate with the UE through the SRB by the target base station before the timer expires and/or before the UE releases the connection with the source base station; the communication module is further configured to communicate with the UE through the SRB and the DRB by the target base station after the timer expires and/or after the UE releases the connection with the source base station.

According to another embodiment of the present invention, there is provided a handover apparatus applied to a UE, including: a second receiving module, configured to receive, by a user equipment UE, timer configuration information sent by a source base station and/or an indication of maintaining connection with the source base station in a handover process from the source base station to a target base station, where the timer configuration information is used to configure a timer for a connection duration between the UE and the source base station; a second releasing module, configured to release, by the UE, the connection with the source base station after the timer expires.

According to still another embodiment of the present invention, there is also provided a storage medium. The storage medium is configured to store program code for performing the steps of:

in the process of switching User Equipment (UE) from a source base station to a target base station, the source base station sends timer configuration information and/or an indication of keeping connection with the source base station to the UE, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station;

after the timer expires, the source base station releases the connection with the UE.

Optionally, the storage medium is further arranged to store program code for performing the steps of:

in the process of switching User Equipment (UE) from a source base station to a target base station, the target base station receives timer configuration information sent by the source base station and/or an instruction for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station;

before the timer is overtime and/or before the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB; and after the timer is overtime and/or the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB and the DRB.

in the process of switching User Equipment (UE) from a source base station to a target base station, the UE receives timer configuration information sent by the source base station and/or an instruction for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station; after the timer expires, the UE releases the connection with the source base station.

According to the invention, in the process of applying for switching the base station by the UE, the source base station sends timer configuration information and/or an indication for keeping connection with the source base station to the UE and the target base station, the timer configuration information is used for setting a timer for the connection duration of the source base station and the UE, the target base station and the UE respectively execute respective operation after receiving the timer configuration information, and the source base station releases the connection with the UE after the timer is overtime. According to the configuration information of the timer, the source base station timely releases the connection with the UE switched to the target base station, the problem of source base station wireless resource waste caused by the fact that the UE autonomously releases the source base station connection after randomly accessing the target base station in the related technology is solved, and the wireless resources of the source base station are timely saved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a flowchart of a method for switching base stations by a UE according to the related art;

fig. 2 is a structural diagram of a layer 2(layer-2) entity of a UE according to the related art;

fig. 3 is a first flowchart of a handover method according to an embodiment of the present invention;

FIG. 4 is a flowchart of a handover method according to an embodiment of the present invention;

fig. 5 is a flowchart of a handover method according to an embodiment of the present invention;

FIG. 6 is a flow chart of a method of timer-based switching in accordance with an alternative embodiment of the present invention;

fig. 7 is a diagram of a reconfiguration SRB of a timer-based handover method according to an alternative embodiment of the present invention;

fig. 8 is a flowchart of a UE-initiated timer for a timer-based handover method according to an alternative embodiment of the present invention;

fig. 9 is a diagram of a reconfiguration DRB for a timer-based handover method according to an alternative embodiment of the present invention;

fig. 10 is a flow chart of a method of handoff based on a release indication in accordance with an alternative embodiment of the present invention;

FIG. 11 is a flowchart of a process for a handover failure according to an alternative embodiment of the invention, shown in FIG. 11;

FIG. 12 is a layer2 processing diagram of a handover failure in accordance with an alternative embodiment of the present invention;

fig. 13 is a block diagram of a switching apparatus applied to a source base station according to an embodiment of the present invention;

fig. 14 is a block diagram of a handover apparatus applied to a target base station according to an embodiment of the present invention;

fig. 15 is a block diagram of a handover apparatus applied to a UE according to an embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

The random access procedure refers to a procedure from a user sending a random access preamble to trying to access the network to a time when a basic signaling connection is established with the network.

Example 1

The embodiment of the present application may be operated in a Long Term Evolution (LTE) system (including but not limited to an LTE system), and a network architecture of a network of the system may include a network side device (e.g., a base station) and a terminal. In this embodiment, a method for switching a base station, which can be operated on the network architecture, is provided, and it should be noted that an operating environment of the method for switching a base station, which is provided in this embodiment of the present application, is not limited to the network architecture.

In this embodiment, a handover method is provided, and fig. 3 is a first flowchart of a handover method according to an embodiment of the present invention, as shown in fig. 3, the flowchart includes the following steps:

step S302, in the process of switching User Equipment (UE) from a source base station to a target base station, the source base station sends timer configuration information and/or an indication for keeping connection with the source base station to the UE, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station;

step S304, after the timer expires, the source base station releases the connection with the UE.

Optionally, the source base station sends a handover command to the UE, where the handover command carries the timer configuration information and/or an indication of maintaining connection with the source base station, and the handover command is used to indicate that the UE is handed over from the source base station to the target base station. In the process of switching the base station by the UE, the source base station may request the target base station for uplink resource configuration information of the UE connected to the target base station, and after receiving the configuration information, the source base station may carry the configuration information in a switching command and issue the switching command to the UE.

Optionally, after the source base station sends the handover command to the UE, the source base station receives notification information issued by the target base station, where the notification information is used to notify the source base station to release the connection with the UE; the source base station informs the UE to release the connection with the source base station. In this embodiment, it should be noted that, after receiving the notification information, the source base station first forwards the notification information to the UE, and then releases the connection with the UE. In this embodiment, when the source base station does not issue the timer configuration information to the UE, the target base station autonomously notifies the source base station to release the connection with the UE, and for the UE, the target base station or the source base station also notifies the UE side to release the connection with the source base station.

Optionally, before the source base station sends the timer configuration information and/or the indication of maintaining the connection with the source base station to the UE, the source base station sends the timer configuration information and/or the indication of maintaining the connection with the source base station to the target base station; and the source base station receives reply information of the target base station, wherein the reply information is used for indicating that the target base station receives the timer configuration information and/or an indication of keeping connection with the source base station. And the source base station sends the timer configuration information to the target base station, and the target base station carries out response operation according to the configuration information.

Optionally, the connection is maintained with the UE through the data radio bearer DRB before the timer expires and/or before the UE releases the connection with the source base station.

According to an embodiment of the present invention, a handover method is provided, and fig. 4 is a second flowchart of the handover method according to the embodiment of the present invention, as shown in fig. 4, the process includes the following steps:

step S402, in the process of switching User Equipment (UE) from a source base station to a target base station, the target base station receives timer configuration information sent by the source base station and/or an instruction for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station;

step S404, before the timer is overtime and/or before the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB; after the timer expires and/or after the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB and the DRB.

The embodiment corresponds to the above embodiment before receiving the timer configuration information sent by the source base station and/or before the indicated timer which keeps the connection with the source base station is overtime and/or before the UE releases the connection with the source base station, and the target base station adopts different modes before and after the time-out after receiving the timer configuration information sent by the source base station and the connection with the UE.

Optionally, before the target base station receives the timer configuration information sent by the source base station and/or the indication of maintaining the connection with the source base station, the method further includes: the target base station sends a random access response to the UE; the target base station receives a control plane signaling sent by the UE, wherein the control plane signaling includes: RRC connection reconfiguration complete message; the target base station informs the source base station to release the connection with the UE, and the target base station informs the UE to release the connection with the source base station. In this embodiment, when the target base station does not receive the timer configuration information sent by the source base station, the target base station autonomously notifies the source base station and the UE to release the connection between them after receiving the RRC connection reconfiguration complete message of the UE.

According to an embodiment of the present invention, a handover method is provided, and fig. 5 is a flowchart three of the handover method according to the embodiment of the present invention, as shown in fig. 5, the flowchart includes the following steps:

step S502, in the process of switching User Equipment (UE) from a source base station to a target base station, the UE receives timer configuration information sent by the source base station and/or an instruction for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer for the connection duration of the UE and the source base station;

step S504, after the timer expires, the UE releases the connection with the source base station.

Optionally, the UE receives a handover command sent by the source base station, where the handover command carries the timer configuration information and/or the indication of maintaining connection with the source base station, and the handover command is used to instruct the UE to handover from the source base station to the target base station. In the process of switching the base station by the UE, the UE must receive a handover command sent by the source base station for indicating the configuration information of the target base station, and the configuration information of the timer may be carried in the handover command.

Optionally, after the UE receives the handover command sent by the source base station, the UE receives a random access response of the target base station, and the UE reconfigures the signaling radio bearer SRB according to the target base station configuration information in the handover command. The radio bearer includes an SRB and a DRB, and the UE reconfigures the SRB in case the DRB is used for connecting with the source base station.

Optionally, after the UE reconfigures the SRB, the UE establishes an independent MAC entity for the SRB, or the SRB and the DRB of the UE share the same MAC entity. Optionally, when the SRB and the DRB share the same MAC entity, the uplink grant information received by the UE from the target base station is used for data transmission of the SRB, and the uplink grant information received by the UE from the source base station is used for data transmission of the DRB; the buffer status report BSR triggered and reported by the UE to the target base station only includes buffer data of the SRB, and the buffer status report BSR triggered and reported by the UE to the source base station only includes buffer data of the DRB.

Optionally, the UE sends a control plane signaling to the target base station, where the control plane signaling includes: RRC connection reconfiguration complete message; the UE receives a notification message of a target base station or a source base station, wherein the notification message is used for notifying the UE to release the connection with the source base station. In this embodiment, the UE directly performs information communication with the target base station without receiving the timer configuration information issued by the source base station, and the target base station notifies the UE and the source base station to release the connection between the UE and the source base station.

Optionally, after the UE receives the random access response of the target base station, before the timer expires and/or before the UE releases the connection with the source base station, the UE performs data transmission with the target base station through the SRB; and after the timer is overtime and/or the UE releases the connection with the source base station, the UE performs data transmission with the target base station through the SRB and the DRB.

Optionally, after the timer expires, the UE reconfigures the RB according to the target base station configuration information in the handover command. Optionally, before the UE reconfigures the RB, the UE reconfigures layer2 entities of the DRBs and the SRBs by using the target base station configuration information under the condition that the SRBs and the DRBs of the UE use the same MAC entity; under the condition that the SRB and the DRB of the UE adopt different MAC entities, the UE adopts the target base station configuration information to rebuild a layer2 entity corresponding to the DRB; and after releasing the MAC entity corresponding to the SRB, the UE reconfigures the SRB into the MAC entity identical to the DRB, or after releasing the layer2 entity corresponding to the SRB, the UE reconstructs the SRB into the MAC entity identical to the DRB. In the detailed procedure of reconfiguring the RB by the UE described in the above embodiment, there is one reconfiguration method when the SRB and the DRB use the same MAC entity, and there are two reconfiguration methods when the SRB and the DRB use different MAC entities.

Optionally, after the UE reconfigures the RB, the UE triggers and reports BSR of the UE, where the BSR includes data of the DRB and the SRB, and the uplink grant of the target base station received by the UE may be used for sending the data of the DRB and the SRB at the same time.

Optionally, after the UE receives the handover command sent by the source base station, the UE establishes a connection with the target base station using the target base station configuration information, and when the connection with the target base station fails to be established, the UE maintains the connection with the source base station, and releases the target base station configuration information. In the process of switching the base station by the UE, the condition of failure of switching the base station is inevitable, if the switching to the target base station fails, the UE keeps connection with the source base station, and then, the network side can trigger the process of switching the base station by the UE again. Optionally, the indication information of the connection establishment failure in the foregoing embodiment includes one of the following types: the handover fails; a random access failure; physical layer RLM detection failure; the RLC retransmission fails.

Fig. 6 is a flowchart of a timer-based handover method according to an alternative embodiment of the present invention, as shown in fig. 6, the steps are as follows:

in step S601, the source base station sends configuration information (corresponding to the timer configuration information in the above embodiment) of "a timer for keeping UE connected to the source base station" to the target base station, where the configuration information may include: the desired duration of the timer. The configuration information indicates that the connection of the UE at the source base station is to be maintained. (Indication of "Timer" configuration and "remaining Connection Indication" in the "Handover Request" message as shown at S601 in FIG. 6)

In step S602, the target base station sets a configuration of "timer for keeping UE connection with the source base station", sets a connection indicating that the UE is to be kept with the source base station, and transmits the connection to the source base station. (the "Timer" configuration and "remaining Connection Indication" in the "Handover Request acknowledgement" message as shown at S602 in FIG. 6)

Step S603, the source base station issues the configuration of a timer for keeping the UE connected with the source base station to the UE when issuing the switching command, issues the indication for keeping the UE connected with the source base station to the UE, records the overtime time of the timer for keeping the UE connected with the source base station of the UE, the source base station receives and transmits data with the UE through the DRB before the timer is overtime, and releases the source base station connection of the UE after the timer is overtime. (as indicated by "Timer" configuration and "remaining Connection Indication" in the "RRC Connection Reconfiguration" message shown in S603 in FIG. 6) (after FIG. 8, there is a description of the steps subsequent to FIG. 6)

After receiving the switching command, the UE starts a timer for keeping the UE connected with the source base station, keeps the connection with the source base station before the time of the timer for keeping the UE connected with the source base station is out, and performs data communication with the source base station through the DRB.

Fig. 7 is a reconfiguration SRB of a handover method based on a timer according to an alternative embodiment of the present invention, as shown in fig. 7, a UE reconfigures an SRB according to configuration information of a target cell. The reconfiguration of the SRB can be done in two ways:

in the method1 (as shown in the method1 in fig. 7), the SRB and the DRB of the UE share the same MAC entity, the uplink grant information received by the UE from the target base station is used for data transmission of the SRB, and the uplink grant information received by the UE from the source base station is used for data transmission of the DRB. The BSR triggered and reported to the target base station by the UE only includes the buffer data of the SRB, and the BSR triggered and reported to the source base station by the UE only includes the buffer data of the DRB.

In manner 2 (e.g., method2 in fig. 7), the UE may establish a separate MAC entity for the SRB, where the MAC entity corresponds to the target base station's connection.

Fig. 8 is a flowchart of a UE-initiated timer of a timer-based handover method according to an alternative embodiment of the present invention, as shown in fig. 8: the UE receives the configuration of the timer at time t1, including the total duration of the timer (Toverall). At time t2, since the UE can start the timer only at time t2 due to the processing delay (Tue) for the information, when the UE starts the timer, the timeout duration of the timer should exclude the processing delay (Toverall-Tue) of the UE.

As shown in fig. 6, in the subsequent step of fig. 6:

step S604, the source base station initiates a data forwarding process to the target base station. (e.g., "SN Status Transfer" at S604 and "Data Forwarding" at S601 in FIG. 6.)

Step S605, the UE initiates a random access procedure to the target base station. (PRACH as in S605 of figure 6.)

Step S606, the target base station replies a random access response. (such as "RAR" of S606 in FIG. 6)

In step S607, the UE reports the Remaining duration of the "timer keeping the UE connected to the source base station" to the target base station (e.g., "Remaining Time" of "RRC Connection Reconfiguration Complete" of S607 in fig. 6 and "main" in fig. 8). The remaining duration may additionally include a processing delay (such as Tlayer2 in fig. 8) for reconfiguration of the layer2 entity after the UE timer expires. The target base station records the residual time of the UE at the time when the timer for keeping the UE connected with the source base station is overtime, and the target base station communicates with the UE through the SRB before the time when the timer for keeping the UE connected with the source base station is overtime. And the target base station communicates with the UE through the SRB and the DRB after the 'timer for keeping the UE connected with the source base station' of the UE is overtime.

The remaining duration of the "timer keeping the UE connected to the source base station" timeout time for the UE by the target base station may be processed as shown in fig. 8: the target base station receives the configuration of the timer at time t3, including the remaining duration (Tremain) of the timer. At time t4, the target base station can only obtain the remaining time length at time t4 due to the processing delay (TeNB) of the information, and since time t4, the eNB considers the end time (Tremain-TeNB) at time t 5.

Step S608, the UE notifies the target base station that the reconfiguration is completed after the layer2 entity reconfiguration is completed. (e.g., "Reset configuration" of S608 in FIG. 6)

Fig. 9 is a DRB reconfiguration diagram of a handover method based on a timer according to an alternative embodiment of the present invention, where the manner of reconfiguring the layer2 entity of the UE may be performed as shown in fig. 9:

if the current configuration mode of the SRB of the UE is mode 1 in S603, the UE reconfigures the layer2 entities of the DRB and the SRB by using the configuration of the target base station.

If the current configuration mode of the SRB of the UE is mode 2 in S603, the UE reconstructs the layer2 entity corresponding to the DRB by using the configuration of the target base station, releases the MAC entity corresponding to the SRB to reconfigure the SRB to the MAC entity identical to the DRB, or releases the layer2 entity corresponding to the SRB and then reconstructs the SRB to the MAC entity identical to the DRB.

Fig. 10 is a flowchart of a handover method based on a release indication according to an alternative embodiment of the present invention, as shown in fig. 10, the steps are as follows:

step S1001, the source base station sends a handover request to the target base station. And indicates that the UE connection at the source base station is to be maintained. (Indication of "remaining Connection Indication" in the "Handover Request" message as shown at S1001 in FIG. 10)

Step S1002, the target base station sends a handover request response to the source base station and indicates the UE to maintain the connection at the source base station. (Indication of "remaining Connection Indication" in the "Handover Request acknowledgement" message shown at S1002 in FIG. 10)

Step S1003, the source base station issues the indication of the connection kept at the source base station to the UE when issuing the switching command, and the source base station transmits and receives data with the UE through the DRB. (indicated by "Relay Connection Indication" in "RRC Connection Reconfiguration" message shown in S1003 in FIG. 10)

And after receiving the switching command, the UE keeps the connection with the source base station and carries out data communication with the source base station through the DRB. The UE reconfigures the SRB according to the configuration information of the target cell, and the reconfiguration method of the SRB is the same as the method described in S603.

Step S1004, the source base station initiates a data forwarding process to the target base station. (e.g., "SN Status Transfer" at S1004 and "Data Forwarding" at S1004 in FIG. 10.)

Step S1005, the UE initiates a random access procedure to the target base station. (PRACH as in S1005 of FIG. 10.)

Step S1006, the target base station replies a random access response. (RAR as in S1006 of FIG. 10.)

In step S1007, the UE reports an RRC Connection Reconfiguration Complete message to the target base station (e.g., "RRC Connection Reconfiguration Complete" in S1007 in fig. 10). The target base station communicates with the UE through the SRB.

Step S1008, the target base station notifies the source base station to release the source base station connection of the UE. (UE Context Release message as S1008 in FIG. 10)

Step S1009, the source base station releases the source base station connection of the UE, and notifies the target base station of the release result. (Release Confirmation message as S1009 in FIG. 10)

Step S1010, the target base station notifies the UE to release the connection of the source base station. (as indicated by the Release Indication in the RRC Connection Reconfiguration message of S1010 in FIG. 10)

Step S1011, the UE releases the connection of the source base station, reconfigures its layer2 entity, and sends a confirmation message to notify the target base station. (e.g., "RRC Connection Reconfiguration Complete" message in FIG. 10)

The method for the UE to reconfigure the layer2 entity is the same as the method described in S608.

Fig. 11 is a flow chart illustrating a process for a handover failure according to an alternative embodiment of the present invention, as shown in fig. 11.

In step S1101, the source base station issues a handover command to the UE and indicates the connection maintained in the source base station. The method for reconfiguring the SRB by the UE is the same as that described in S603.

Step S1102, if the UE fails to perform wireless connection during the handover, the UE maintains data communication with the source base station, does not trigger the connection re-establishment procedure, and reports a failure indication to the network side, where the failure indication information may include a specific failure type: the handover fails; a random access failure; physical layer RLM detection failure; the RLC retransmission fails. And the UE releases the configuration information of the target base station. (Failure Indication message of S1102 in FIG. 11)

Fig. 12 is a layer2 processing diagram of a handover failure according to an alternative embodiment of the present invention, and as shown in fig. 12, layer2 of a UE may be processed in the manner of fig. 12:

mode 1: if the current SRB and the DRB of the UE share the same MAC entity, the UE reconfigures the SRB entity by using the configuration information of the source base station.

Mode 2: if the SRB and the DRB of the UE adopt different MAC entities, the UE adopts the configuration of the source base station to reconfigure the SRB, the UE releases the MAC entity corresponding to the SRB to reconfigure the SRB into the MAC entity same as the DRB, or the UE releases the layer2 entity corresponding to the SRB and then reconstructs the SRB into the MAC entity same as the DRB.

After receiving the UE indication, the source base station may select another cell to perform handover on the UE.

Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

Example 2

In this embodiment, a switching device is further provided, and the device is used to implement the foregoing embodiments and preferred embodiments, and the description of the device is omitted for brevity. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.

Fig. 13 is a block diagram of a switching apparatus applied to a source base station according to an embodiment of the present invention, and as shown in fig. 13, the switching apparatus includes:

a sending module 132, configured to send, to a user equipment UE, timer configuration information and/or an indication of maintaining connection with a source base station to the UE in a handover process of the UE from the source base station to a target base station, where the timer configuration information is used to configure a timer for a connection duration of the UE with the source base station;

a first releasing module 134, connected to the sending module 132, for releasing the connection with the UE by the source base station after the timer expires.

Fig. 14 is a block diagram of a handover apparatus applied to a target base station according to an embodiment of the present invention, and as shown in fig. 14, the apparatus includes:

a first receiving module 142, configured to, in a handover process of a UE from a source base station to a target base station, receive timer configuration information sent by the source base station and/or an indication of maintaining connection with the source base station, where the timer configuration information is used to configure a timer for a connection duration of the UE with the source base station;

a communication module 144, connected to the first receiving module 142, for communicating with the UE via the SRB before the timer expires and/or before the UE releases the connection with the source base station; the communication module is further configured to communicate with the UE via the SRB and the DRB by the target base station after the timer expires and/or after the UE releases the connection with the source base station.

Fig. 15 is a block diagram of a switching apparatus applied to a UE according to an embodiment of the present invention, and as shown in fig. 15, the switching apparatus includes:

a second receiving module 152, configured to receive, by the second receiving module 152, timer configuration information and/or an indication of maintaining connection with a source base station sent by the source base station in a handover process of a UE from the source base station to a target base station, where the timer configuration information is used to configure a timer for a connection duration of the UE with the source base station;

a second releasing module 154 connected to the second receiving module 152, for releasing the connection with the source base station by the UE after the timer expires.

It should be noted that, the above modules may be implemented by software or hardware, and for the latter, the following may be implemented, but not limited to: the modules are all positioned in the same processor; alternatively, the modules are respectively located in different processors in any combination.

Example 3

The embodiment of the invention also provides a storage medium. Alternatively, in the present embodiment, the storage medium may be configured to store program codes for performing the following steps:

s1, in the process of switching UE from a source base station to a target base station, the source base station sends timer configuration information and/or an indication of keeping connection with the source base station to the UE, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station;

s2, after the timer is over, the source base station releases the connection with the UE;

the storage medium may be configured to store program code for performing the steps of:

s3, in the process of switching UE from a source base station to a target base station, the target base station receives timer configuration information sent by the source base station and/or an indication of keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer of the connection duration of the UE and the source base station;

s4, before the timer is overtime and/or before the UE releases the connection with the source base station, the target base station communicates with the UE through SRB; after the timer expires and/or after the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB and the DRB.

s5, in the process of switching UE from a source base station to a target base station, the UE receives timer configuration information sent by the source base station and/or an indication for keeping connection with the source base station, wherein the timer configuration information is used for configuring a timer for the connection duration of the UE and the source base station;

s6, after the timer expires, the UE releases the connection with the source base station.

Optionally, in this embodiment, the storage medium may include, but is not limited to: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

Optionally, in this embodiment, the processor executes the method steps described in the above embodiments according to the program code stored in the storage medium.

Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and this embodiment is not described herein again.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method of handover, comprising:

in the process of switching User Equipment (UE) from a source base station to a target base station, the source base station sends an indication of keeping connection with the source base station to the UE;

after the source base station sends a switching command to the UE and the target base station receives an RRC connection reconfiguration completion message sent by the UE, the source base station receives notification information issued by the target base station, wherein the notification information is used for notifying the source base station to release the connection with the UE;

the target base station informs the UE to release the connection with the source base station;

wherein before the source base station sends the indication of keeping the connection with the source base station to the UE, the method further comprises:

the source base station sends the indication of keeping connection with the source base station to a target base station;

the source base station receives reply information of the target base station, wherein the reply information is used for indicating that the target base station receives the indication of keeping the connection with the source base station;

wherein the method further comprises:

and the source base station sends a switching command to the UE, wherein the switching command carries an indication of keeping connection with the source base station, and the switching command is used for indicating the UE to be switched from the source base station to a target base station.

2. The method of claim 1, further comprising:

before the UE releases the connection with the source base station, the source base station keeps the connection with the UE through a Data Radio Bearer (DRB).

3. A method of handover, comprising:

in the process of switching User Equipment (UE) from a source base station to a target base station, the target base station receives an indication that the UE is connected with the source base station and sent by the source base station;

the target base station sends a random access response to the UE;

the target base station receives a control plane signaling sent by the UE, wherein the control plane signaling comprises: RRC connection reconfiguration complete message;

the target base station informs a source base station of releasing connection with the UE, and the target base station informs the UE of releasing connection with the source base station;

before the UE releases the connection with the source base station, the target base station communicates with the UE through an SRB; after the UE releases the connection with the source base station, the target base station communicates with the UE through the SRB and the DRB;

before the target base station receives the indication that the UE connected with the source base station is kept, wherein the indication is sent by the source base station, the method further comprises the following steps:

the target base station receives an instruction sent by a source base station for keeping the connection with the source base station;

the target base station sends reply information to the source base station, wherein the reply information is used for indicating that the target base station receives the indication of keeping the connection with the source base station;

wherein the method further comprises:

4. A method of handover, comprising:

in the process of switching User Equipment (UE) from a source base station to a target base station, the UE receives an indication that the source base station sends connection maintenance to the source base station;

the UE sends a control plane signaling to a target base station, wherein the control plane signaling comprises: RRC connection reconfiguration complete message;

after the source base station sends a switching command to the UE and the target base station receives an RRC connection reconfiguration completion message sent by the UE, the source base station receives notification information issued by the target base station and is used for notifying the source base station to release the connection with the UE;

the UE receives a notification message of a target base station, and is used for notifying the UE to release the connection with a source base station;

before the UE receives the indication that the source base station sends the connection maintaining request, the method further includes:

wherein the method further comprises:

and the UE receives a switching command sent by the source base station, wherein the switching command carries the indication of keeping the connection with the source base station, and the switching command is used for indicating the UE to be switched from the source base station to a target base station.

5. The method of claim 4, further comprising:

before the UE releases the connection with the source base station, the UE keeps the connection with the source base station through a Data Radio Bearer (DRB).

6. The method of claim 4, further comprising:

after the UE receives a switching command sent by a source base station, the UE receives a random access response of a target base station, and the UE reconfigures a Signaling Radio Bearer (SRB) according to target base station configuration information in the switching command.

7. The method of claim 6, further comprising:

after the UE reconfigures the SRB, the UE establishes an independent MAC entity for the SRB, or the SRB and the DRB of the UE share the same MAC entity.

8. The method of claim 7, further comprising:

under the condition that the SRB and the DRB share the same MAC entity, the uplink authorization information received by the UE from the target base station is used for data transmission of the SRB, and the uplink authorization information received by the UE from the source base station is used for data transmission of the DRB;

the buffer status report BSR triggered and reported to the target base station by the UE only includes buffer data of the SRB, and the buffer status report BSR triggered and reported to the source base station by the UE only includes buffer data of the DRB.

9. The method of claim 6, wherein after the UE receives the random access response of the target base station, the method further comprises:

before the UE releases the connection with the source base station, the UE transmits data with the target base station through the SRB;

and after the UE releases the connection with the source base station, the UE carries out data transmission with the target base station through the SRB and the DRB.

10. The method of claim 4, further comprising:

and the UE reconfigures a Radio Bearer (RB) according to the target base station configuration information in the switching command.

11. The method of claim 10, wherein prior to the UE reconfiguring RBs, the method further comprises:

under the condition that the SRB and the DRB of the UE adopt the same MAC entity, the UE adopts the target base station configuration information to reconfigure the layer2 entities of the DRB and the SRB;

under the condition that the SRB and the DRB of the UE adopt different MAC entities, the UE adopts the target base station configuration information to reconstruct a layer2 entity corresponding to the DRB;

and under the condition that the SRB and the DRB of the UE adopt different MAC entities, the UE releases the MAC entity corresponding to the SRB and reconfigures the SRB into the MAC entity same as the DRB, or the UE releases the layer2 entity corresponding to the SRB and reconstructs the SRB into the MAC entity same as the DRB.

12. The method of claim 11, wherein after the UE reconfigures the RBs, the method further comprises:

and triggering and reporting the BSR of the UE, wherein the BSR comprises data of the DRB and the SRB, and the uplink authorization of the target base station received by the UE can be used for sending the data of the DRB and the SRB at the same time.

13. The method of claim 4, wherein after the UE receives the handover command from the source base station, the method further comprises:

the UE establishes connection with the target base station by using the configuration information of the target base station, the UE keeps the connection with the source base station under the condition that the connection with the target base station fails, the UE releases the configuration information of the target base station, and the UE reports the indication information of the connection failure with the target base station to the source base station.

14. The method according to claim 13, wherein the information indicating the connection failure comprises one of the following types: the handover fails; a random access failure; physical layer RLM detection failure; the RLC retransmission fails.

15. A switching device applied to a source base station, comprising:

the system comprises a sending module, a receiving module and a sending module, wherein the sending module is used for sending an instruction of keeping connection with a source base station to User Equipment (UE) in the process of switching the UE from the source base station to a target base station;

the sending module is further configured to send a handover command to the UE at the source base station, and the target base station receives an RRC connection reconfiguration complete message sent by the UE;

wherein the switching device is further configured to:

before sending an instruction of keeping connection with a source base station to UE, sending the instruction of keeping connection with the source base station to a target base station, and receiving reply information of the target base station, wherein the reply information is used for indicating that the target base station receives the instruction of keeping connection with the source base station;

wherein the switching device is further configured to: and sending a switching command to the UE, wherein the switching command carries an indication of keeping connection with a source base station, and the switching command is used for indicating the UE to be switched from the source base station to a target base station.

16. A handover apparatus applied to a target base station, comprising:

a first receiving module, configured to receive, by a source base station, an indication that a UE keeps being connected with the source base station when a user equipment UE is switched from the source base station to a target base station, where a switching command sent by the source base station to the UE carries the indication that the UE keeps being connected with the source base station, and the switching command is used to indicate that the UE is switched from the source base station to the target base station;

the first receiving module is further configured to receive a control plane signaling sent by the UE after the target base station sends a random access response to the UE, where the control plane signaling includes: RRC connection reconfiguration complete message; a communication module, configured to communicate with the UE through an SRB by the target base station before the UE releases the connection with the source base station; the communication module is further configured to communicate with the UE through the SRB and the DRB by the target base station after the UE releases the connection with the source base station;

the communication module is further configured to notify a source base station to release connection with the UE, and notify the UE to release connection with the source base station;

wherein the switching device is further configured to:

before receiving an instruction sent by a source base station that UE keeps being connected with the source base station, receiving the instruction sent by the source base station and used for keeping being connected with the source base station, and sending reply information back to the source base station, wherein the reply information is used for indicating that the target base station receives the instruction for keeping being connected with the source base station.

17. A switching device applied to a UE side of a User Equipment (UE), comprising:

the second receiving module is used for receiving an instruction which is sent by the source base station and keeps connection with the source base station in the process that the user equipment UE is switched from the source base station to the target base station;

the switching device is configured to receive a notification message of a target base station after the UE sends the control plane signaling to the target base station, and is configured to notify the UE to release a connection with a source base station;

wherein the control plane signaling comprises: RRC connection reconfiguration complete message;

after the source base station sends a switching command to the UE and the target base station receives an RRC connection reconfiguration completion message sent by the UE, the source base station receives notification information issued by the target base station and is used for notifying the source base station to release the connection with the UE; the switching device sends the instruction of keeping connection with the source base station to the target base station before receiving the instruction of keeping connection with the source base station sent by the source base station; the source base station receives reply information of the target base station, wherein the reply information is used for indicating that the target base station receives the indication of keeping the connection with the source base station;

wherein the switching device is further configured to: and receiving a switching command sent by the source base station, wherein the switching command carries the indication of keeping the connection with the source base station, and the switching command is used for indicating the UE to be switched from the source base station to a target base station.