CN110475301B

CN110475301B - Method and apparatus for UE handover

Info

Publication number: CN110475301B
Application number: CN201810445167.7A
Authority: CN
Inventors: 黄晓舸; 汤涉; 张晨璐; 郑倩
Original assignee: Vivo Mobile Communication Co Ltd
Current assignee: Vivo Mobile Communication Co Ltd
Priority date: 2018-05-10
Filing date: 2018-05-10
Publication date: 2020-11-13
Anticipated expiration: 2038-05-10
Also published as: CN110475301A

Abstract

The application provides a method and equipment for UE switching, wherein the method comprises the following steps: if the member base stations of the base station cluster can be directly connected through the Xn interface, the source base station directly interacts with the target base station through the Xn interface to obtain information required by UE switching; if member base stations of a base station cluster cannot be directly connected through an Xn interface, the source base station interacts information required by UE switching with a target base station through a first interface and a second interface, wherein the first interface is the Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is the Xn interface between the target base station and the cluster head base station; the base station cluster is a pre-constructed cluster containing the source base station and the target base station. The method and the equipment can realize UE switching between different base stations or between cells deployed under different base stations.

Description

Method and apparatus for UE handover

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for UE handover.

Background

In a fifth Generation (5th-Generation, 5G) mobile communication system, small cell base stations (gnbs) will be densely deployed in a cellular network in order to meet the increasing traffic demand. Due to the small coverage area of these densely deployed small cell base stations, during the process of moving a User Equipment (UE), a handover from one small cell base station (usually called a source base station) to another small cell base station (usually called a target base station) is required, and this handover process is often called UE handover.

Currently, the switching mode for reducing Random Access Channel-less (RACH-less) can only realize the UE switching between cells deployed in the same base station, but cannot realize the UE switching between different base stations or between cells deployed in different base stations.

Disclosure of Invention

The embodiment of the application provides a method and equipment for UE switching, so as to realize UE switching between different base stations or between cells deployed under different base stations.

In a first aspect, a method for UE handover is provided, where the method is applied to a source base station, and the method includes:

if the member base stations of the base station cluster can be directly connected through the Xn interface, the source base station directly interacts with the target base station through the Xn interface to obtain information required by UE switching;

if member base stations of a base station cluster cannot be directly connected through an Xn interface, the source base station interacts information required by UE switching with a target base station through a first interface and a second interface, wherein the first interface is the Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is the Xn interface between the target base station and the cluster head base station;

the base station cluster is a pre-constructed cluster containing the source base station and the target base station.

In a second aspect, a method for UE handover is provided, which is applied to a target base station, and includes:

if the member base stations of the base station cluster can be directly connected through the Xn interface, the target base station directly interacts with the source base station through the Xn interface to exchange information required by UE switching;

if member base stations of a base station cluster cannot be directly connected through an Xn interface, the target base station interacts information required by UE switching with a source base station through a first interface and a second interface, wherein the first interface is the Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is the Xn interface between the target base station and the cluster head base station;

In a third aspect, a method for UE handover is provided, where the method is applied to a cluster head base station in a base station cluster, and the method includes:

if the member base stations of the base station cluster can not be directly connected through the Xn interface, the cluster head base station receives information required by UE switching from a source base station through a first interface, sends the information required by UE switching from the source base station to a target base station through a second interface, receives the information required by UE switching from the target base station through the second interface, and sends the information required by UE switching from the target base station to the source base station through the first interface;

the base station cluster is a pre-constructed cluster including the source base station and the target base station, the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station.

In a fourth aspect, a network device is provided, the network device comprising:

the first interaction module is used for interacting information required by UE switching with a target base station directly through an Xn interface if member base stations of a base station cluster can be directly connected through the Xn interface;

a second interaction module, configured to interact, by the source base station, information required for UE handover with the target base station through a first interface and a second interface if member base stations of a base station cluster cannot be directly connected through an Xn interface, where the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station;

Optionally, there are a plurality of UEs to be switched connected to the source base station, and the network device further includes:

the acquisition module is used for acquiring the information of the UE to be switched, which is related to the priority sequence;

a generating module, configured to generate the priority of the UE to be switched according to the information related to the priority ranking;

a switching mode determining module, configured to determine, based on the priority of the UE to be switched, a switching mode corresponding to the UE to be switched;

wherein, the information required by the UE handover includes: a UE handover request from the source base station, and response information for the UE handover request from the target base station;

the UE switching request carries the switching mode, the response information carries access resource information distributed by the target base station to the UE to be switched according to the switching mode, and the access resource information is used for the UE to be switched to switch.

Optionally, if member base stations of the base station cluster can be directly connected through an Xn interface, and the UE switching request also carries identity information of the UE to be switched;

the response information is determined by the target base station according to the UE switching request and the UE identity authentication result from the cluster head base station, and the UE identity authentication result is obtained by the cluster head base station through authenticating the UE to be switched according to the identity information of the UE to be switched from the target base station.

Optionally, if the member base stations of the base station cluster can be directly connected through an Xn interface, and if the switching mode is a low-interruption delay switching mode, the switching mode is a low-interruption delay switching mode

The access resource information includes: the method comprises the steps of pre-allocating uplink authorization, a first timing time difference and a dedicated random access lead code;

the first timing time difference is the timing time difference between the source base station and the target base station, and the first timing time difference is used for determining the timing time difference between the UE to be switched and the target base station;

the low interruption delay switching mode comprises the following steps: and switching by adopting a random access reduction RACH-less mode, and if the switching by adopting the RACH-less mode fails, switching by adopting a non-competitive random access mode.

Optionally, if member base stations of the base station cluster cannot be directly connected through an Xn interface, and the UE switching request also carries identity information of the UE to be switched;

the response information is determined by the target base station according to the UE switching request and the UE identity authentication result from the cluster head base station, and the UE identity authentication result is obtained by authenticating the UE to be switched by the cluster head base station according to the identity information of the UE to be switched from the source base station.

Optionally, if the member base stations of the base station cluster cannot be directly connected through the Xn interface, and if the switching mode is a low-interruption delay switching mode, then

The access resource information includes: the pre-allocated uplink grant, the second timing difference, the third timing difference and the dedicated random access preamble;

wherein the second timing difference is a timing difference between the source base station and the cluster head base station, the third timing difference is a timing difference between the target base station and the cluster head base station, and the second timing difference and the third timing difference are used for determining a timing difference between the UE to be switched and the target base station;

Optionally, the switching manner determining module is specifically configured to:

if the priority of the UE to be switched is the first level, determining a low-interruption time delay switching mode as a switching mode corresponding to the UE to be switched;

if the priority of the UE to be switched is the second level, determining a non-competitive random access mode as a switching mode corresponding to the UE to be switched;

if the priority of the UE to be switched is the third level, determining a competitive random access mode as a switching mode corresponding to the UE to be switched;

wherein the first level is higher than the second level, the second level is higher than the third level, and the low interrupt delay switching mode includes: and switching by adopting a random access reduction RACH-less mode, and if the switching by adopting the RACH-less mode fails, switching by adopting a non-competitive random access mode.

Optionally, the information related to priority ranking of the UE to be switched includes at least one of the following information:

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

and obtaining the Reference Signal Received Power (RSRP) of the target base station in the measurement report of the UE to be switched.

Optionally, the base station cluster is constructed in advance according to the geographical location information of the base station and the load information of the base station.

In a fifth aspect, a network device is provided, which includes:

a third interaction module, configured to, if member base stations of a base station cluster can be directly connected through an Xn interface, directly interact, by the target base station, with the source base station through the Xn interface, information required for UE handover;

a fourth interaction module, configured to interact, by the target base station, information required for UE handover with the source base station through a first interface and a second interface if member base stations of a base station cluster cannot be directly connected through an Xn interface, where the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station;

Optionally, there are a plurality of UEs to be switched connected to the source base station;

the information required by the UE handover includes: a UE handover request from the source base station, and response information for the UE handover request from the target base station;

the UE switching request carries a switching mode corresponding to the UE to be switched, the switching mode is determined by the source base station according to the priority of the UE to be switched, and the priority of the UE to be switched is determined by the source base station according to the information sequence of the UE to be switched, wherein the information sequence is related to the priority sequence information; the response information carries access resource information allocated by the target base station to the UE to be switched according to the switching mode, and the access resource information is used for the UE to be switched to carry out UE switching.

Optionally, if member base stations of the base station cluster can be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over, the network device further includes:

an authentication request sending module, configured to directly send an identity authentication request for the UE to be switched to the cluster head base station through an Xn interface, where the identity authentication request carries identity information of the UE to be switched;

a first authentication result receiving module, configured to directly receive, through an Xn interface, a UE identity authentication result from the cluster head base station, where the UE identity authentication result is obtained by authenticating, by the cluster head base station, the UE to be switched according to identity information of the UE to be switched from the target base station;

and the response information is determined by the target base station according to the UE switching request and the UE identity authentication result from the cluster head base station.

Optionally, if the member base stations of the base station cluster cannot be directly connected through an Xn interface, and the UE handover request further carries the identity information of the UE to be handed over, the network device further includes:

a second authentication result receiving module, configured to receive, through the second interface, a UE identity authentication result from the cluster head base station, where the UE identity authentication result is obtained by authenticating, by the cluster head base station, the UE to be switched according to identity information of the UE to be switched from the source base station;

Optionally, if the member base stations of the base station cluster cannot be directly connected through the Xn interface, and if the target handover mode is a low-interruption delay handover mode, the target handover mode is a low-interruption delay handover mode

the low interruption delay switching mode comprises the following steps: switching is carried out by adopting a random access reduction RACH-less mode, and if the switching fails by adopting the RACH-less mode, switching is carried out by adopting a non-competitive random access mode.

Optionally, if the priority of the UE to be switched is the first level, the switching mode corresponding to the UE to be switched is a low interruption delay switching mode;

if the priority of the UE to be switched is the second level, the switching mode corresponding to the UE to be switched is a non-competitive random access mode;

if the priority of the UE to be switched is the third level, the switching mode corresponding to the UE to be switched is a competitive random access mode;

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

In a sixth aspect, a network device is provided, which includes:

a fifth interaction module, configured to, if member base stations of the base station cluster cannot be directly connected through an Xn interface, receive, by the cluster head base station, information required for UE handover from a source base station through a first interface, send, to a target base station, information required for UE handover from the source base station through a second interface, receive, by the second interface, information required for UE handover from the target base station, and send, to the source base station, information required for UE handover from the target base station through the first interface;

Optionally, the network device further includes:

and the storage module is used for storing the UE information in the base station cluster, and the UE information is used for identifying the identity of the UE to be switched.

Optionally, the network device further includes:

the authentication information acquisition module is used for acquiring the identity information of the UE to be switched;

the authentication module is used for determining the UE identity authentication result aiming at the UE to be switched according to the identity information of the UE to be switched and the UE information stored in the cluster head base station;

an authentication result sending module, configured to send the UE identity authentication result to the target base station;

the UE identity authentication result is used for the target base station to determine response information aiming at the UE to be switched, the response information carries access resource information distributed by the target base station for the UE to be switched according to a switching mode corresponding to the UE to be switched, the access resource information is used for the UE to be switched to perform UE switching, the switching mode corresponding to the UE to be switched is determined by the source base station according to the priority of the UE to be switched, and the priority of the UE to be switched is determined by the source base station according to information of the UE to be switched, wherein the information is related to priority sequencing information.

Optionally, the member base stations of the base station cluster may be directly connected through an Xn interface, and the authentication information obtaining module is specifically configured to:

and directly receiving an identity authentication request aiming at the UE to be switched from the target base station through an Xn interface, wherein the identity authentication request carries identity information of the UE to be switched.

Optionally, the member base stations of the base station cluster can be directly connected through an Xn interface, and if the switching mode corresponding to the UE to be switched is a low interruption delay switching mode, the UE to be switched is connected through the Xn interface

Optionally, the member base stations of the base station cluster may not be directly connected through an Xn interface, and the authentication information obtaining module is specifically configured to:

and receiving a UE switching request aiming at the UE to be switched from the source base station through the first interface, wherein the UE switching request carries the identity information of the UE to be switched.

Optionally, the member base stations of the base station cluster cannot be directly connected through an Xn interface, and if the switching mode corresponding to the UE to be switched is a low-interruption delay switching mode, the UE to be switched cannot be directly connected through the Xn interface

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

Optionally, the method further comprises:

and the adding module is used for adding the UE to be switched to the base station cluster and storing the identity information of the UE to be switched if the identity authentication result indicates that the UE to be switched is not the UE in the base station cluster.

In a seventh aspect, a network device is provided, the terminal device comprising a memory, a processor and a wireless communication program stored on the memory and operable on the processor, the wireless communication program, when executed by the processor, implementing the steps of the method according to any one of the first to third aspects.

In an eighth aspect, there is provided a computer readable medium having stored thereon a wireless communication program which, when executed by a processor, performs the steps of the method according to any one of the first to third aspects.

In the embodiment of the application, a base station cluster including a source base station and a target base station is constructed in advance, so that the source base station and the target base station which belong to the base station cluster can be directly connected and communicated through an Xn interface, or connected and communicated through an Xn interface between the source base station and a cluster head base station and an Xn interface between the target base station and the cluster head base station, thereby realizing the interaction of information required by UE switching between different base stations or between cells deployed under different base stations, and further realizing the UE switching between different base stations or between cells deployed under different base stations.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.

Fig. 1 is a schematic diagram of a cellular network architecture according to an embodiment of the present invention.

Fig. 2 is a schematic flow chart of a method for UE handover according to an embodiment of the present invention.

Fig. 3 is another schematic flow chart of a method for UE handover according to an embodiment of the present invention.

Fig. 4 is a schematic flow chart of another method for UE handover according to an embodiment of the present invention.

Fig. 5 is another schematic flow chart of another method for UE handover according to an embodiment of the present invention.

Fig. 6 is still another schematic flow chart of another method for UE handover according to an embodiment of the present invention.

Fig. 7 is a schematic flow chart of still another method for UE handover according to an embodiment of the present invention.

Fig. 8 is another schematic flow chart of still another method for UE handover according to an embodiment of the present invention.

Fig. 9 is a detailed flowchart of a method for UE handover according to an embodiment of the present invention.

Fig. 10 is another detailed flowchart of a method for UE handover according to an embodiment of the present invention.

Fig. 11 is a schematic structural diagram of a network device 1100 according to an embodiment of the present invention.

Fig. 12 is a schematic diagram of another structure of a network device 1100 according to an embodiment of the invention.

Fig. 13 is a schematic structural diagram of a network device 1300 according to an embodiment of the present invention.

Fig. 14 is a schematic diagram of another structure of a network device 1300 according to an embodiment of the present invention.

Fig. 15 is a schematic diagram of another structure of a network device 1300 according to an embodiment of the present invention.

Fig. 16 is a schematic structural diagram of a network device 1600 according to an embodiment of the invention.

Fig. 17 is a schematic diagram of another structure of a network device 1600 according to an embodiment of the invention.

Fig. 18 is a schematic structural diagram of a network device 1000 according to an embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be understood that the technical solutions of the embodiments of the present application may be applied to various communication systems, for example: a Global System for Mobile communications (GSM) System, a Code Division Multiple Access (CDMA) System, a Wideband Code Division Multiple Access (WCDMA) System, a General Packet Radio Service (GPRS), a Long Term Evolution (Long Term Evolution, LTE) System, an LTE Frequency Division Duplex (FDD) System, an LTE Time Division Duplex (TDD), a Universal Mobile Telecommunications System (UMTS) or a Worldwide Interoperability for Microwave Access (WiMAX) communication System, a 5G System, or a New Radio (NR) System.

A Terminal device (UE), which may also be referred to as a Mobile Terminal (Mobile Terminal), a Mobile Terminal device, or the like, may communicate with at least one core Network via a Radio Access Network (RAN, for example), where the Terminal device may be a Mobile Terminal, such as a Mobile phone (or a "cellular" phone) and a computer having the Mobile Terminal, such as a portable, pocket, handheld, computer-embedded or vehicle-mounted Mobile device, and may exchange languages and/or data with the Radio Access Network.

The network device is a device deployed in a radio access network device and configured to provide a UE handover function for a terminal device, where the network device may be a Base Station, and the Base Station may be a Base Transceiver Station (BTS) in GSM or CDMA, a Base Station (NodeB) in WCDMA, an evolved Node B (eNB or e-NodeB) in LTE, or a 5G Base Station (gNB).

It should be noted that, when describing a specific embodiment, the sequence numbers of the processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the internal logic of the processes, and should not constitute any limitation to the implementation process of the embodiment of the present application.

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

First, in order to more clearly understand the inventive concept of the present invention, a method for UE handover and a network architecture supported by a network device according to an embodiment of the present invention are described below with reference to fig. 1.

Referring to fig. 1, a Radio Access Network (RAN) includes a number of small cell base stations and UEs, and a Core Network (NGC) includes an Access and Mobility Management Function (AMF) server, a Session Management Function (SMF) server, and a User plane Function (User UPF) server.

As shown in fig. 1, in the embodiment of the present invention, neighboring small cell base stations (or base stations) may be divided into a base station cluster (cluster) in advance according to geographical location information of the small cell base stations (or base stations) and load information of the small cell base stations (or base stations), and the entire cellular network is divided into base station clusters of different sizes, such as the first base station cluster 11, the second base station cluster 12 and the third base station cluster 13 in fig. 1. Any base station in each base station cluster may serve as a cluster head base station (cluster head gNB) of the base station cluster, such as 111 in the first base station cluster 11, 121 in the second

base station cluster

12, and 131 in the third base station cluster 13 in fig. 1, which may serve as cluster head base stations of the first base station cluster 11, the second base station cluster 12, and the third base station cluster 13, respectively, and the base stations except the cluster head base station in each base station cluster may be referred to as member base stations. The cluster head base station in each base station cluster can store information of the UEs in the cluster, especially identity information of the UEs in the cluster, and update the information of the UEs in the cluster as the UEs join or leave. In the embodiment of the present invention, the cluster head base station may further assist the UE handover, and a specific assisted handover process will be described in detail in the method for UE handover described below.

As shown in fig. 1, in the embodiment of the present invention, member base stations in each base station cluster may be directly connected through an Xn interface (that is, may communicate through an Xn interface), or may not be directly connected through an Xn interface, but the member base stations may be directly connected with a cluster head base station through an Xn interface. Each base station cluster on the RAN side can be connected with the NGC through the NG interface.

On this basis, a method for UE handover, which is applied to the source base station, is described below with reference to fig. 2 and 3.

In one embodiment, as shown in fig. 2, a method for UE handover applied to a source base station may include the steps of:

step 201, if the member base stations of the base station cluster can be directly connected through the Xn interface, the source base station directly interacts with the target base station through the Xn interface with information required by UE handover.

The Xn interface is a network interface supporting interconnection between two base stations (gnbs), and supports direct transmission of data and signaling, similar to the X2 interface in LTE.

Step 202, if the member base stations of the base station cluster can not be directly connected through the Xn interface, the source base station interacts with the target base station through the first interface and the second interface with information required by the UE handover.

In step 202, the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station.

The base station cluster is a pre-constructed cluster containing the source base station and the target base station. For the establishment of the base station cluster, refer to fig. 1 and the above description of fig. 1.

Information required for UE handover includes, but is not limited to: a UE handover request from the source base station, and response information for the UE handover request from the target base station, and so on.

It should be noted that, in the handover execution phase (the UE handover process is generally divided into three phases of handover preparation, handover execution and handover completion), the information actually required for the UE handover may be information configured by the source base station based on the response information and including the access Resource, for example, information configured by the source base station using Radio Resource Control (RRC) after receiving the response information from the target base station.

According to the method for UE switching provided by the embodiment of the invention, the base station cluster comprising the source base station and the target base station is constructed in advance, so that the source base station and the target base station which belong to the base station cluster can be directly connected and communicated through the Xn interface, or the Xn interface between the source base station and the cluster head base station and the Xn interface between the target base station and the cluster head base station, thereby realizing the interaction of information required by UE switching between different base stations or between cells deployed under different base stations, and further realizing the UE switching between different base stations or between cells deployed under different base stations.

Since there may be a plurality of UEs to be switched connected to the source base station in some cases, for example, during operation of a high-speed rail, there may be a lot of passengers to simultaneously switch from a source base station group to a target base station, and of the plurality of UEs to be switched, some UEs to be switched may have higher requirements on the handover interruption delay and the handover success rate, and some UEs to be switched may have less high requirements on the handover interruption delay and the handover success rate. Therefore, as shown in fig. 3, in another embodiment, a method for UE handover applied to a source base station may further include:

step 203, obtaining the information related to the priority sequence of the UE to be switched.

As an example, the information related to the priority ranking of the UE to be handed over may comprise at least one of the following information:

quality of Service (QoS) requirements of the UE to be switched in the communication process;

the service type of the UE to be switched; and

and obtaining the Reference Signal Receiving Power (RSRP) of the target base station in the measurement report of the UE to be switched.

The service type of the UE to be switched may be a service type occurring on the UE to be switched when the source base station sends a UE switching request to the target base station, and the service types may be, for example, a voice call type, a video call type, or a short message type.

And 204, generating the priority of the UE to be switched according to the information related to the priority sequence.

For example, the higher the QoS requirements of the UE to be switched, the more important the traffic type of the UE to be switched (e.g., voice call may be more important to the user than the traffic type of short message), and the higher the RSRP requirements of the UE to be switched, the higher the rank of the UE to be switched.

Step 205, determining a switching mode corresponding to the UE to be switched based on the priority of the UE to be switched.

In general, the higher the priority of a UE to be switched, the faster the switching speed of the switching manner determined for the UE to be switched and/or the higher the switching success rate.

Since the switching speeds of the three manners, i.e., the RACH-less switching manner, the non-contention random access manner, and the contention random access manner, are sequentially decreased, and the access success rate of the non-contention random access manner is greater than the access success rate of the contention random access manner, in an example, the step 205 may specifically include:

and if the priority of the UE to be switched is the third level, determining a competitive random access mode as a switching mode corresponding to the UE to be switched.

Wherein the first level is higher than the second level, the second level is higher than the third level, and the low interrupt delay switching mode includes: and switching by adopting a random access reduction RACH-less mode, and if the switching by adopting the RACH-less mode fails, switching by adopting a non-competitive random access mode. For the convenience of understanding, the low-interruption delay handover mode may also be referred to as "RACH-less + non-contention random access" for short.

It is easy to understand that the priority is determined by sequencing the UEs to be switched, and the switching mode corresponding to the UEs to be switched is determined according to the priority, so that the UEs to be switched with high priority can be ensured to have smaller switching interruption time delay and higher switching success rate, so as to improve user experience.

It should be further noted that, when the RACH-less handover manner is used to implement UE handover, the UE can obtain two key information, namely a timing adjustment indication (timing adjustment indication) with the target base station and a pre-allocated uplink grant (allocated uplink grant), which are the precondition for successful handover; if the two pieces of key information cannot be obtained, the UE cannot communicate with the target base station, and therefore UE switching cannot be achieved.

In the embodiment of the invention, the source base station and the target base station are divided into the same base station cluster in advance, and the cluster head base station of the base station cluster can manage the member base stations (the member base stations and the cluster head base station can be directly connected through the Xn interface), so that the target base station can directly communicate with the source base station through the Xn interface and transmit the two pieces of key information to the source base station; or the target base station can communicate with the source base station through the first interface and the second interface, the two pieces of key information are transmitted to the source base station, the source base station configures the two pieces of key information to the UE to be switched, and then the UE switching between different base stations or between cells deployed under different base stations can be realized by using an RACH-less switching mode.

In addition, the UE handover process is generally divided into three stages, namely, a handover preparation stage, a handover execution stage and a handover completion stage, and since the synchronization step between the UE to be handed over and the target base station in the handover execution stage and the step of allocating uplink to the UE to be handed over by the target base station can be omitted when the RACH-less handover mode is used for handover, in an embodiment of the present invention, if the RACH-less handover mode is used, the interruption delay in the UE handover process can be reduced, which is also the reason that the aforementioned "RACH-less + non-contention random access" is referred to as a low interruption delay handover mode.

Furthermore, since the access success rate of the non-contention random access manner is higher than that of the contention random access manner, for the UE to be switched with a higher priority (for example, the first level or the second level in the above description), the low-interruption delay switching manner or the non-contention access switching manner is selected, and compared with the selection of the contention random access switching manner, the switching success rate of the UE to be switched with a higher priority can be improved.

On the basis of the embodiment shown in fig. 3, in more detail, the UE handover request from the source base station may carry a handover mode corresponding to the UE to be handed over, and the response information from the target base station may carry access resource information allocated by the target base station to the UE to be handed over according to the handover mode, where the access resource information is used for the UE to be handed over to perform UE handover. The following scenario illustrates the specific content of the access resource information.

In a first example, it is assumed that member base stations of the base station cluster can be directly connected through an Xn interface, and the UE handover request also carries identity information of the UE to be handed over; the response information may be determined by the target base station according to the UE handover request and the UE identity authentication result from the cluster head base station, and the UE identity authentication result is obtained by the cluster head base station authenticating the UE to be handed over according to the identity information of the UE to be handed over from the target base station.

The identity information of the UE may include, but is not limited to, the following information: a source base station ID, a Cell Radio Network Temporary identity (C-RNTI) of the source base station, and the like.

Correspondingly, the UE information stored in the cluster head base station may include: a UE X2 signaling context reference of a UE to be switched at a source base station, an Evolved Packet Core (EPC) signaling context reference of the UE to be switched, an RRC context of a C-RNTI of the UE to be switched at the source base station, an Evolved Radio Access Bearer (E-RAB) context, an ID of the source base station, an ID of a target base station, a Cell Radio Network Temporary Identifier (C-RNTI) of the source base station, a C-RNTI of the target base station, and Radio Network Layer (RNL) and Transport Network Layer (TNL) addressing information, which are not listed herein.

More specifically, the response information may be: when the target base station determines that the UE to be switched is the UE in the base station cluster according to the UE identity authentication result from the cluster head base station, the target base station determines according to the UE switching request from the source base station, and the target base station allocates access resource information to the UE to be switched according to the switching mode corresponding to the UE to be switched carried in the UE switching request. It should be noted that, if the target base station determines that the UE to be switched is not the UE in the base station cluster according to the UE identity authentication result from the cluster head base station, the response information is determined in the manner of the current standard or protocol.

It is understood that whether the UE to be switched is the UE in the base station cluster or not is identified, and when the UE to be switched is determined to be the UE in the base station cluster, the response information is determined according to the UE switching request, the method for switching the UE provided by the embodiment of the invention is adopted to realize the switching of the UE to be switched, instead of adopting the existing switching process to realize the switching of the UE to be switched, so that the switching rate and the switching success rate of the UE in the base station cluster can be improved.

Further, in this first example, if the handover mode is a low interrupt latency handover mode, the access resource information may include: preassigned uplink grant, first timing difference T₁And a dedicated random access preamble (dedicated RACH preamble).

Wherein the first timing difference T₁Is a Timing difference (alternatively referred to as Timing Advance (TA)) between the source base station and the target base station, and the first Timing difference T is₁And the method is used for determining the timing adjustment indication (timing adjustment indication) between the UE to be switched and the target base station. And, the preassigned uplink grant and the first timing difference T₁The dedicated random access preamble is the access resource information used when a non-competitive random access mode is adopted after the RACH-less mode is failed to switch.

In the second example, if member base stations of a base station cluster cannot be directly connected through an Xn interface, and the UE handover request also carries identity information of the UE to be handed over; the response information is determined by the target base station according to the UE handover request and the UE identity authentication result from the cluster head base station, and the UE identity authentication result is obtained by the cluster head base station authenticating the UE to be handed over according to the identity information of the UE to be handed over from the source base station.

Likewise, the response information may be: when the target base station determines that the UE to be switched is the UE in the base station cluster according to the UE identity authentication result from the cluster head base station, the target base station determines according to the UE switching request from the source base station, and the target base station allocates access resource information to the UE to be switched according to the switching mode corresponding to the UE to be switched carried in the UE switching request. It should be noted that, if the target base station determines that the UE to be switched is not the UE in the base station cluster according to the UE identity authentication result from the cluster head base station, the response information is determined in the manner of the current standard or protocol.

And, whether the UE to be switched is the UE in the base station cluster is identified, and when the UE to be switched is determined to be the UE in the base station cluster, response information is determined according to the UE switching request, the method for switching the UE provided by the embodiment of the invention is adopted to realize the switching of the UE to be switched, instead of adopting the current switching process to realize the switching of the UE to be switched, so that the switching rate and the switching success rate of the UE in the base station cluster can be improved.

Further, in this second example, if the handover mode is a low interrupt latency handover mode, the access resource information may include: preassigned uplink grant, second timing difference T₂A third timing difference T₃And a dedicated random access preamble.

Wherein the second timing difference T₂Is the timing difference between the source base station and the cluster head base station, the third timing difference T₃Is a timing difference between the target base station and the cluster head base station, and the second timing difference T₂And said third timing difference T₃And the method is used for determining the timing adjustment indication (timing adjustment indication) between the UE to be switched and the target base station. And, the pre-allocated uplink grant, the second timing difference T₂And said third timing difference T₃The dedicated random access preamble is the access resource information used when a non-competitive random access mode is adopted after the RACH-less mode is failed to switch.

In the first example and the second example, please refer to the above for the meaning of the low interrupt latency switching mode, which is not described herein again. Based on the above analysis, it can be known that the interruption delay in the UE handover process can be reduced by using the low interruption delay handover mode.

It should be noted that, in the embodiments shown in fig. 2 and fig. 3, the base station cluster is constructed in advance according to the geographical location information of the base station and the load information of the base station.

A method for UE handover applied to a source base station according to an embodiment of the present invention is described above with reference to fig. 2 and 3. A method for UE handover applied to a target base station according to an embodiment of the present invention is described below with reference to fig. 4 to 6.

Referring to fig. 4, in one embodiment, a method for UE handover applied to a target base station may include the following steps:

step 401, if the member base stations of the base station cluster can be directly connected through the Xn interface, the target base station directly interacts with the source base station through the Xn interface with information required by the UE handover.

Step 402, if the member base stations of the base station cluster can not be directly connected through the Xn interface, the target base station interacts with the source base station through the first interface and the second interface, wherein the information is needed by UE switching.

In step 402, the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station.

Optionally, the UE switching request from the source base station may carry a switching manner corresponding to the UE to be switched, the switching manner corresponding to the UE to be switched may be determined by the source base station according to the priority of the UE to be switched, and the priority of the UE to be switched may be determined by the source base station according to the information ranking of the UE to be switched, which is related to the priority ranking information; the response information carries access resource information allocated by the target base station to the UE to be switched according to the switching mode, and the access resource information is used for the UE to be switched to carry out UE switching. The following will exemplify the contents contained in the access resource information in each case.

Since there may be a plurality of UEs to be switched connected to the source base station in some cases, for example, during operation of a high-speed rail, there may be a lot of passengers to simultaneously switch from a source base station group to a target base station, and of the plurality of UEs to be switched, some UEs to be switched may have higher requirements on the handover interruption delay and the handover success rate, and some UEs to be switched may have less high requirements on the handover interruption delay and the handover success rate. Therefore, the priority is determined by sequencing the UE to be switched, and the switching mode corresponding to the UE to be switched is determined according to the priority, so that the UE to be switched with high priority can be ensured to have smaller switching interruption time delay and higher switching success rate, and the user experience is improved.

In one example, the information related to the priority ranking of the UE to be handed off may include at least one of the following information:

the service type of the UE to be switched; and

As the switching speed in three modes, namely the RACH-less switching mode, the non-contention random access mode and the contention random access mode, decreases in sequence, and the access success rate of the non-contention random access mode is greater than that of the contention random access mode, as an example, there may be a corresponding relationship between the priority of the UE to be switched and the switching mode corresponding to the UE to be switched as follows:

and if the priority of the UE to be switched is the first level, the switching mode corresponding to the UE to be switched is a low-interruption time-delay switching mode.

And if the priority of the UE to be switched is the second level, the switching mode corresponding to the UE to be switched is a non-competitive random access mode.

And if the priority of the UE to be switched is the third level, the switching mode corresponding to the UE to be switched is a competitive random access mode.

Wherein the first level is higher than the second level, the second level is higher than the third level, and the low-interruption time-delay switching mode is RACH-less + non-contention random access as described above.

It should be noted that, when the RACH-less handover manner is used to implement UE handover, the UE can obtain two key information, namely a timing adjustment indication (timing adjustment indication) with the target base station and a pre-allocated uplink grant (preallocated uplink grant), which are the precondition of successful handover; if the two pieces of key information cannot be obtained, the UE cannot communicate with the target base station, and therefore UE switching cannot be achieved.

In a first example, as shown in fig. 5, if member base stations of the base station cluster can be directly connected through an Xn interface, and the UE handover request also carries identity information of the UE to be handed over, a method for UE handover applied to a target base station may further include:

step 403, directly sending an identity authentication request for the UE to be switched to the cluster head base station through an Xn interface.

Wherein, the identity authentication request carries the identity information of the UE to be switched.

Step 404, receiving the UE identity authentication result from the cluster head base station directly through the Xn interface.

And the UE identity authentication result is obtained by authenticating the UE to be switched by the cluster head base station according to the identity information of the UE to be switched from the target base station.

On this basis, the response information may be determined by the target base station according to the UE handover request and the UE identity authentication result from the cluster head base station.

Further, in this first example, if the handover mode is a low interrupt latency handover mode, the access resource information may include: the system comprises a pre-allocated uplink grant, a first timing difference and a dedicated random access preamble.

The first timing time difference is the timing time difference between the source base station and the target base station, and the first timing time difference is used for determining the timing time difference between the UE to be switched and the target base station. And, the preassigned uplink grant and the first timing difference T₁For access resource information used in the process of switching by using RACH-less modeThe dedicated random access preamble is access resource information used when a non-contention random access mode is adopted after the RACH-less mode is failed to switch.

In a second example, as shown in fig. 6, member base stations of the base station cluster cannot be directly connected through an Xn interface, and the UE handover request also carries identity information of the UE to be handed over, so that the method for UE handover applied to a target base station may further include:

step 405, receiving a UE identity authentication result from the cluster head base station through the second interface.

The UE identity authentication result is obtained by authenticating the UE to be switched by the cluster head base station according to the identity information of the UE to be switched from the source base station;

Further, in the second example shown in fig. 6, if the target handover mode is low interrupt latency handoverIn this way, the access resource information may include: preassigned uplink grant, second timing difference T₂A third timing difference T₃And a dedicated random access preamble.

It should be noted that, in the embodiments shown in fig. 4 to fig. 6, the base station cluster is constructed in advance according to the geographical location information of the base station and the load information of the base station.

A method for UE handover applied to a target base station according to an embodiment of the present invention is described above with reference to fig. 4 to 6. A method for UE handover applied to a cluster head base station according to an embodiment of the present invention is described below with reference to fig. 7 to 8.

As shown in fig. 7, in an embodiment, a method for UE handover applied to a cluster head base station may include:

step 701, if the member base stations of the base station cluster cannot be directly connected through the Xn interface, the cluster head base station receives information required for UE handover from a source base station through a first interface, sends information required for UE handover from the source base station to a target base station through a second interface, receives information required for UE handover from the target base station through the second interface, and sends information required for UE handover from the target base station to the source base station through the first interface.

The base station cluster is a pre-constructed cluster including the source base station and the target base station, the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station. For the establishment of the base station cluster, refer to fig. 1 and the above description of fig. 1.

The method for switching the UE, which is applied to the cluster head base station, provided by the embodiment of the invention, has the advantages that the base station cluster comprising the source base station and the target base station is constructed in advance, so that the source base station and the target base station which belong to the base station cluster can be directly connected and communicated through the Xn interface, or the Xn interface between the source base station and the cluster head base station and the Xn interface between the target base station and the cluster head base station, the interaction of information required by the UE switching between different base stations or between cells deployed under different base stations is realized, and the UE switching between different base stations or between cells deployed under different base stations is further realized.

Referring to fig. 8, in another embodiment, a method for UE handover applied to a cluster head base station may further include:

and step 702, storing the UE information in the base station cluster.

The UE information is used for identifying the identity of the UE to be switched, and is specifically used for identifying whether the UE to be switched is the UE in the base station cluster where the cluster head base station, the source base station and the target base station are located by combining the identity information of the UE to be switched.

As mentioned above, the UE information in the base station cluster saved by the cluster head base station may include, but is not limited to: a UE X2 signaling context reference of the UE to be switched at the source base station, an EPC signaling context reference of the UE to be switched, an RRC context of a C-RNTI of the UE to be switched in the source base station, an E-RAB context, an ID of the source base station, an ID of the target base station, a C-RNTI of the source base station, a C-RNTI of the target base station, RNL and TNL addressing information, and the like, which are not enumerated herein.

Optionally, with continuing reference to fig. 8, in yet another embodiment, a method for UE handover applied to a cluster head base station may further include:

step 703, acquiring the identity information of the UE to be switched.

As mentioned above, the identity information of the UE may include, but is not limited to, the following information: source base station ID, C-RNTI of the source base station, etc.

In the first example, if the member base stations of the base station cluster can be directly connected through an Xn interface, step 703 may specifically include: and directly receiving an identity authentication request aiming at the UE to be switched from the target base station through an Xn interface, wherein the identity authentication request carries identity information of the UE to be switched.

In a second example, if the member base stations of the base station cluster cannot be directly connected through the Xn interface, step 703 may specifically include: and receiving a UE switching request aiming at the UE to be switched from the source base station through the first interface, wherein the UE switching request carries the identity information of the UE to be switched.

Step 704, determining the UE identity authentication result for the UE to be switched according to the identity information of the UE to be switched and the UE information stored in the cluster head base station.

Step 705, sending the UE identity authentication result to the target base station.

And the UE identity authentication result is used for the target base station to determine response information aiming at the UE to be switched.

The response information carries access resource information distributed by the target base station to the UE to be switched according to the switching mode corresponding to the UE to be switched, the access resource information is used for the UE to be switched to switch, the switching mode corresponding to the UE to be switched is determined by the source base station according to the priority of the UE to be switched, and the priority of the UE to be switched is determined by the source base station according to the information of the UE to be switched, which is related to the priority sequencing information. The following will exemplify the specific contents of the access resource information in each case.

As an example, the information related to the priority ranking of the UE to be switched includes at least one of the following information:

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

In general, the higher the priority of a UE to be switched, the faster the switching speed of the switching manner determined for the UE to be switched, and the higher the switching success rate.

Further, on the basis of the first example in step 703, if the handover mode corresponding to the UE to be handed over is a low interruption delay handover mode, the access resource information includes: a pre-allocated uplink grant (preallocated uplink grant), a first timing difference T1, and a dedicated random access preamble.

Wherein the first timing difference T₁Is the timing difference between the source base station and the target base station, and the first timing difference T₁And the method is used for determining the timing adjustment indication (timing adjustment indication) between the UE to be switched and the target base station. And, the preassigned uplink grant and the first timing difference T₁The dedicated random access preamble is the access resource information used when a non-competitive random access mode is adopted after the RACH-less mode is failed to switch.

On the basis of the second example in step 703, if the handover mode corresponding to the UE to be handed over is a low interruption delay handover mode, the access resource information includes: preassigned uplink grant, second timing difference T₂A third timing difference T₃And a dedicated random access preamble.

Optionally, in the embodiments shown in fig. 7 to 8, the base station cluster is constructed in advance according to the geographical location information of the base station and the load information of the base station.

Optionally, the method for UE handover, applied to a cluster head base station, provided in the embodiment of the present invention may further include: and if the identity authentication result indicates that the UE to be switched is not the UE in the base station cluster, adding the UE to be switched to the base station cluster, and storing the identity information of the UE to be switched so as to update the UE information in the base station cluster.

The method for UE handover applied to the cluster head base station is described in detail above in conjunction with fig. 7 and 8. A method for UE handover provided by the embodiments of the present application will be described with reference to fig. 9 and 10 in two more detailed embodiments.

Referring to fig. 9, in an embodiment, assuming that member base stations of a base station cluster can be directly connected through an Xn interface, the following interaction process exists among a UE to be switched, a source base station, a target base station, a cluster head base station, an AMF server, and a UPF server:

in the handover preparation phase 81:

step 801, a source base station configures a measurement process for a UE to be switched.

Step 802, the UE to be switched reports the measurement report to the source base station.

And step 803, the source base station makes a UE switching decision based on the measurement report, determines the priority of the UE to be switched through sequencing, and determines the switching mode corresponding to the UE to be switched through the determined priority.

Step 804, the source base station sends a UE switching request to the target base station, where the UE switching request carries a switching manner corresponding to the UE to be switched, identity information of the UE to be switched (determined according to a measurement report and Radio Resource Management (RRM) information), and other information.

Step 805, the target base station sends a UE identity authentication request to the cluster head base station, where the UE identity authentication request carries identity information of the UE to be switched.

Step 806, the cluster head base station obtains a UE identity authentication result (whether the UE to be switched is the UE in the base station cluster) according to the identity information of the UE to be switched carried in the UE identity authentication request and the UE information in the base station cluster where the cluster head base station is stored in the cluster head base station, and stores the identity information of the UE to be switched when it is determined that the UE to be switched is not the UE in the base station cluster; and the cluster head base station feeds back the UE identity authentication result to the target base station.

Step 807, when the target base station determines that the UE to be switched is the UE in the cluster according to the UE identity authentication result, based on the switching manner corresponding to the UE to be switched carried in the UE switching request, the target base station configures access resources for the UE to be switched, and generates response information for the received UE switching request, where the response information includes access resource information. The allocated access resource may be, for example: dedicated resources and dedicated random access preambles.

And 808, the target base station sends the response information to the source base station. When the handover mode corresponding to the UE to be handed over is the low-interruption delay handover mode, the response information includes the dedicated random access preamble allocated in step 807, the pre-allocated uplink grant (preallocated uplink grant) and the first time difference T₁The first time difference T₁Can be used for the UE to be switched to calculate the timing adjustment indication between the UE to be switched and the target base station, and the timing adjustment indication and the first time difference T₁And the distance from the UE to be switched to the target base station.

In the handover execution phase 82:

step 809, the source base station reconfigures the access resource to the UE to be handed over through the RRC message, for example, reconfigures two pieces of key information, namely, a pre-allocated uplink grant (preallocated uplink grant) and a timing adjustment indication (timing adjustment indication), to the UE to be handed over.

Step 810, the source base station submits a Serial Number (SN) to the target base station.

Step 811, synchronizing the UE to be switched with the target base station.

Specifically, when the corresponding handover mode of the UE to be handed over determined in step 803 is "RACH-less + non-contention random access", the UE to be handed over first synchronizes with the target base station by using an RACH-less process, obtains a secret key from the target base station and configures a security algorithm; and if the synchronization by adopting the RACH-less process fails, synchronizing the random access preamble reconfigured in the step 809 with the target base station by adopting a non-contention random access process.

When the handover mode corresponding to the UE to be handed over determined in step 803 is non-contention random access, the UE to be handed over uses the random access preamble reconfigured in step 809 to synchronize with the target base station by using a non-contention random access procedure.

When the handover mode corresponding to the UE to be handed over determined in step 803 is contention random access, the UE to be handed over uses the random access preamble reconfigured in step 809 to synchronize with the target base station by using a contention random access procedure.

Step 812, the target base station allocates uplink grant to the UE to be switched.

It should be noted that, when the handover mode corresponding to the UE to be handed over is determined in step 803 to be "RACH-less + non-contention random access", steps 811 to 813 may be omitted, so that the interruption delay in the UE handover process may be reduced.

In the handover complete phase 83:

step 813, the UE to be switched sends RRC reconfiguration complete information to the target base station.

Step 814, the target base station sends a path switch request message to the AMF to trigger a Core network (e.g., 5th Generation Core, 5GC) to transmit a downlink grant to the target base station while establishing an NG-C interface with the target base station.

Step 815, the core network transmits the downlink data to the target base station.

Step 816, the AMF confirms the path switch to the target base station.

817, the target base station informs the source base station to release the context of the UE to be switched.

Step 818, the source base station releases the context of the UE to be switched.

In the embodiment shown in fig. 9, a base station cluster including a source base station and a target base station is pre-constructed, so that the source base station and the target base station belonging to the base station cluster can be directly connected and communicated through an Xn interface, thereby implementing interaction of information required for UE handover between different base stations or between cells deployed under different base stations, and further implementing UE handover between different base stations or between cells deployed under different base stations.

Referring to fig. 10, in another embodiment, assuming that member base stations of a base station cluster cannot be directly connected through an Xn interface, the following interaction process exists among a UE to be switched, a source base station, a target base station, a cluster head base station, an AMF server, and a UPF server:

in the handover preparation phase 91:

the steps 901 to 903 are performed in the same way as the steps 801 to 803 shown in fig. 9, please refer to the steps 801 to 803.

Step 904, the source base station sends a UE handover request to the cluster head base station, where the UE handover request carries a handover mode corresponding to the UE to be handed over, identity information of the UE to be handed over (determined according to a measurement report and Radio Resource Management (RRM) information), and other information.

Step 905, the cluster head base station forwards the received UE handover request to the target base station, and meanwhile, the cluster head base station obtains a UE identity authentication result (whether the UE to be handed over is the UE in the base station cluster) according to the identity information of the UE to be handed over carried in the UE handover request and the UE information in the base station cluster where the cluster head base station is stored in the cluster head base station, and stores the identity information of the UE to be handed over when it is determined that the UE to be handed over is not the UE in the base station cluster; and the cluster head base station feeds back the UE identity authentication result to the target base station.

Step 906 is the same as step 807 in the embodiment shown in FIG. 9, see step 807.

Step 907, the target base station sends the response information to the cluster head base station.

And 908, forwarding the response information to the source base station by the cluster head base station.

In the handover execution phase 92:

step 909, the source base station reconfigures the access resource to the UE to be handed over through the RRC message, for example, the dedicated random access preamble, the pre-allocated uplink grant (preallocated uplink grant) and the timing adjustment indication (timing adjustment indication) are reconfigured to the UE to be handed over. Specifically, when the switching mode corresponding to the UE to be switched is the low-interruption delay switching mode, the response information includes pre-allocated informationUplink grant (preallocated uplink grant), second time difference T₂And a third time difference T₃Second time difference T₂And a third time difference T₃Can be used for the UE to be switched to calculate the timing adjustment indication between the UE to be switched and the target base station, and the timing adjustment indication and the second time difference T₂A third time difference T₃And the distance from the UE to be switched to the target base station. Please refer to the above for the definition of the second time difference and the third time difference, which are not described herein.

Step 910, the source base station submits a Serial Number (SN) to the cluster head base station.

And step 911, the cluster head base station transfers the SN to the target base station.

Steps 912 through 919 correspond to steps 811 through 818 in the embodiment of fig. 9, as described above with respect to fig. 9.

In the embodiment shown in fig. 10, a base station cluster including a source base station and a target base station is pre-constructed, so that the source base station and the target base station belonging to the base station cluster can be in connection communication through an Xn interface between the source base station and the cluster head base station and an Xn interface between the target base station and the cluster head base station, thereby implementing interaction of information required for UE handover between different base stations or between cells deployed under different base stations, and further implementing UE handover between different base stations or between cells deployed under different base stations.

In addition, in the prior art, UE handover is performed through Make-Before-Break (Make-Before-Break) and Dual Connectivity (DC). Wherein, the switching process of first connection and then disconnection is approximately: after receiving the RRC information, the UE to be switched is not disconnected with the source base station until the UE initiates uplink transmission to the target base station, and then the UE to be switched is separated from the source base station. The switching process of dual connectivity is roughly: adding a target base station as an auxiliary base station (Secondary gNB) by a source base station, carrying and separating in a Packet Data Convergence Protocol (PDCP) layer of the source base station, and transmitting Data to UE to be switched through the source base station and the target base station respectively; and then, role switching is carried out between the source base station and the target base station, the target base station becomes a Master gNB (Master gNB), and finally the UE to be switched is separated from the source base station.

However, in the handover based on the first-connection and then-disconnection handover mode, the source base station may copy data to the target base station, and the UE to be handed over needs to establish protocol stacks for the source base station and the target base station respectively and needs to process data transmitted by the two base stations at the same time, which may occupy more resources. In the handover based on the dual connectivity handover mode, the UE to be handed over also needs to establish protocol stacks for the source base station and the target base station, and also involves bearer separation and relocation of the PDCP layer during the handover process, so the handover procedure is complicated and the generated signaling overhead is large.

In the method for UE handover provided in each embodiment of the present invention, since the base station cluster is constructed, the transmission process of information required for UE handover is simplified, and thus the above-mentioned problems of first connection and then disconnection and dual connection can be overcome.

The above is a description of a method for UE handover according to an embodiment of the present invention, and a network device corresponding to the above method embodiment is described below.

Fig. 11 shows a schematic structural diagram of a network device 1100 according to an embodiment of the present invention, where the network device may specifically be a source base station, and as shown in fig. 11, the network device 1100 may include:

a first interaction module 1101, configured to, if member base stations of a base station cluster can be directly connected through an Xn interface, interact, by the source base station, information required for UE handover with a target base station directly through the Xn interface;

a second interaction module 1102, configured to interact, by a source base station and a target base station, information required for UE handover through a first interface and a second interface if member base stations of a base station cluster cannot be directly connected through an Xn interface, where the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station;

The information required for the UE handover includes, but is not limited to: a UE handover request from the source base station, and response information for the UE handover request from the target base station.

Optionally, in another embodiment, there are a plurality of UEs to be switched connected to the source base station, as shown in fig. 12, the network device 1100 may further include:

an obtaining module 1103, configured to obtain information related to priority ranking of the UE to be switched.

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

A generating module 1104, configured to generate the priority of the UE to be switched according to the information related to the priority ranking.

A switching mode determining module 1105, configured to determine, based on the priority of the UE to be switched, a switching mode corresponding to the UE to be switched.

In an example, the handover mode determining module 1105 may be specifically configured to: if the priority of the UE to be switched is the first level, determining a low-interruption time delay switching mode as a switching mode corresponding to the UE to be switched; if the priority of the UE to be switched is the second level, determining a non-competitive random access mode as a switching mode corresponding to the UE to be switched; and if the priority of the UE to be switched is the third level, determining a competitive random access mode as a switching mode corresponding to the UE to be switched.

The first level is higher than the second level, which is higher than the third level, and the meaning of the low interrupt latency switching manner is referred to in the method embodiment section.

Optionally, in an example, the member base stations of the base station cluster may be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over;

Optionally, on the basis of this example, if the handover mode is a low-interruption delay handover mode, the access resource information includes: the method comprises the steps of pre-allocating uplink authorization, a first timing time difference and a dedicated random access lead code;

the first timing time difference is the timing time difference between the source base station and the target base station, and the first timing time difference is used for determining the timing time difference between the UE to be switched and the target base station.

Optionally, in another example, if member base stations of a base station cluster cannot be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over; the response information is determined by the target base station according to the UE handover request and the UE identity authentication result from the cluster head base station, and the UE identity authentication result is obtained by the cluster head base station authenticating the UE to be handed over according to the identity information of the UE to be handed over from the source base station.

Optionally, on the basis of the another example, if the handover mode is a low-interruption delay handover mode, the access resource information includes: the system comprises a pre-allocated uplink grant, a second timing difference, a third timing difference and a dedicated random access preamble.

The second timing time difference is the timing time difference between the source base station and the cluster head base station, the third timing time difference is the timing time difference between the target base station and the cluster head base station, and the second timing time difference and the third timing time difference are used for determining the timing time difference between the UE to be switched and the target base station.

The network device 1100 shown in fig. 11 to 12 can enable a source base station and a target base station belonging to a base station cluster to directly connect and communicate through an Xn interface through a pre-constructed base station cluster including the source base station and the target base station, or connect and communicate through an Xn interface between the source base station and a cluster head base station and an Xn interface between the target base station and the cluster head base station, thereby implementing interaction of information required for UE handover between different base stations or between cells deployed under different base stations, and further implementing UE handover between different base stations or between cells deployed under different base stations.

In addition, by identifying whether the UE to be switched is the UE in the base station cluster or not, and determining the response information according to the UE switching request when the UE to be switched is determined to be the UE in the base station cluster, the method for switching the UE provided by the embodiment of the invention is adopted to realize the switching of the UE to be switched instead of adopting the current switching process to realize the switching of the UE to be switched, so that the switching rate and the switching success rate of the UE in the base station cluster can be improved.

The terminal devices shown in fig. 11 to fig. 12 may be used to implement the embodiments of the method for UE handover shown in fig. 2 to fig. 3, and please refer to the above method embodiments for relevant points.

Fig. 13 shows a schematic structural diagram of a network device 1300 according to an embodiment of the present invention, where the network device may specifically be a target base station, and as shown in fig. 13, the network device 1300 may include:

a third interaction module 1301, configured to, if member base stations of a base station cluster can be directly connected through an Xn interface, interact, by the target base station, information required for UE handover with the source base station directly through the Xn interface;

a fourth interaction module 1302, configured to interact, by the target base station, information required for UE handover with a source base station through a first interface and a second interface if member base stations of a base station cluster cannot be directly connected through an Xn interface, where the first interface is an Xn interface between the source base station and a cluster head base station of the base station cluster, and the second interface is an Xn interface between the target base station and the cluster head base station;

Optionally, there are a plurality of UEs to be switched connected to the source base station; the information required for the UE handover may include: a UE handover request from the source base station, and response information for the UE handover request from the target base station.

Optionally, as an example, if the priority of the UE to be switched is the first level, the switching mode corresponding to the UE to be switched is a low-interruption delay switching mode; if the priority of the UE to be switched is the second level, the switching mode corresponding to the UE to be switched is a non-competitive random access mode; and if the priority of the UE to be switched is the third level, the switching mode corresponding to the UE to be switched is a competitive random access mode.

Optionally, as an example, the information related to the priority ranking of the UE to be switched includes at least one of the following information:

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

Optionally, in another embodiment, if member base stations of the base station cluster can be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over, as shown in fig. 14, the network device 1300 may further include:

an authentication request sending module 1303, configured to directly send an identity authentication request for the UE to be switched to the cluster head base station through an Xn interface, where the identity authentication request carries identity information of the UE to be switched.

A first authentication result receiving module 1304, configured to directly receive, through an Xn interface, a UE identity authentication result from the cluster head base station, where the UE identity authentication result is obtained by authenticating, by the cluster head base station, the UE to be switched according to the identity information of the UE to be switched from the target base station.

Optionally, on the basis of the embodiment shown in fig. 14, if the handover mode is a low interruption delay handover mode, the access resource information includes: the system comprises a pre-allocated uplink grant, a first timing difference and a dedicated random access preamble.

Optionally, in another embodiment, if member base stations of the base station cluster cannot be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over, as shown in fig. 14, the network device 1300 may further include:

a second authentication result receiving module 1305, configured to receive, through the second interface, a UE identity authentication result from the cluster head base station, where the UE identity authentication result is obtained by authenticating, by the cluster head base station, the UE to be switched according to identity information of the UE to be switched from the source base station.

Optionally, on the basis of the embodiment shown in fig. 14, if the target handover mode is a low interruption delay handover mode, the access resource information includes: the system comprises a pre-allocated uplink grant, a second timing difference, a third timing difference and a dedicated random access preamble.

The network device 1300 shown in fig. 13 to fig. 15, through a pre-constructed base station cluster including a source base station and a target base station, may enable the source base station and the target base station belonging to the base station cluster to directly connect and communicate through an Xn interface, or connect and communicate through an Xn interface between the source base station and a cluster head base station and an Xn interface between the target base station and the cluster head base station, thereby implementing interaction of information required for UE handover between different base stations or between cells deployed under different base stations, and further implementing UE handover between different base stations or between cells deployed under different base stations.

The terminal devices shown in fig. 13 to fig. 15 may be used to implement the embodiments of the method for UE handover shown in fig. 4 to fig. 6, and please refer to the above method embodiments for relevant points.

Fig. 16 shows a schematic structural diagram of a network device 1600 provided in an embodiment of the present invention, where the network device may specifically be a cluster head base station, and as shown in fig. 16, the network device 1600 may include:

a fifth interaction module 1601, configured to receive, by the cluster head base station, information required for UE handover from a source base station through a first interface, send, to a target base station through a second interface, information required for UE handover from the source base station through the second interface, and send, to the source base station, information required for UE handover from the target base station through the first interface.

Optionally, in another embodiment, as shown in fig. 17, the network device 1600 may further include:

a storing module 1602, configured to store UE information in the base station cluster, where the UE information is used to identify an identity of a UE to be switched.

Optionally, in yet another embodiment, as shown in fig. 17, the network device 1600 may further include:

an authentication information obtaining module 1603, configured to obtain identity information of the UE to be switched.

In a first example, if the member base stations of the base station cluster can be directly connected through an Xn interface, the authentication information obtaining module may be specifically configured to: and directly receiving an identity authentication request aiming at the UE to be switched from the target base station through an Xn interface, wherein the identity authentication request carries identity information of the UE to be switched.

In a second example, if the member base stations of the base station cluster cannot be directly connected through an Xn interface, the authentication information obtaining module may be specifically configured to: and receiving a UE switching request aiming at the UE to be switched from the source base station through the first interface, wherein the UE switching request carries the identity information of the UE to be switched.

An authentication module 1604, configured to determine a UE identity authentication result for the UE to be switched according to the identity information of the UE to be switched and the UE information stored in the cluster head base station.

An authentication result sending module 1605, configured to send the UE identity authentication result to the target base station.

Optionally, in another embodiment, if the priority of the UE to be switched is the first level, the switching mode corresponding to the UE to be switched is a low-interruption delay switching mode; if the priority of the UE to be switched is the second level, the switching mode corresponding to the UE to be switched is a non-competitive random access mode; and if the priority of the UE to be switched is the third level, the switching mode corresponding to the UE to be switched is a competitive random access mode. Wherein the first level is higher than the second level, which is higher than the third level.

Optionally, when the first example is adopted in the authentication information obtaining module 1603, if the switching mode corresponding to the UE to be switched is a low-interruption delay switching mode, the access resource information includes: the system comprises a pre-allocated uplink grant, a first timing difference and a dedicated random access preamble. The first timing time difference is the timing time difference between the source base station and the target base station, and the first timing time difference is used for determining the timing time difference between the UE to be switched and the target base station.

Optionally, when the second example is adopted in the authentication information obtaining module 1603, if the switching mode corresponding to the UE to be switched is a low-interruption delay switching mode, the access resource information includes: the system comprises a pre-allocated uplink grant, a second timing difference, a third timing difference and a dedicated random access preamble. The second timing time difference is the timing time difference between the source base station and the cluster head base station, the third timing time difference is the timing time difference between the target base station and the cluster head base station, and the second timing time difference and the third timing time difference are used for determining the timing time difference between the UE to be switched and the target base station.

Optionally, in another embodiment, the information related to the priority ranking of the UE to be switched includes at least one of the following information:

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

Optionally, in another embodiment, the base station cluster is constructed in advance according to the geographical location information of the base station and the load information of the base station.

Optionally, in yet another embodiment, the network device 1600 may further include:

The network device 1600 shown in fig. 16 to 17, through the pre-constructed base station cluster including the source base station and the target base station, may enable the source base station and the target base station belonging to the base station cluster to directly connect and communicate through an Xn interface, or connect and communicate through an Xn interface between the source base station and the cluster head base station and an Xn interface between the target base station and the cluster head base station, thereby implementing interaction of information required by UE handover between different base stations or between cells deployed under different base stations, and further implementing UE handover between different base stations or between cells deployed under different base stations.

The terminal devices shown in fig. 16 to 17 may be used to implement the embodiments of the method for UE handover shown in fig. 7 to 8, and please refer to the above method embodiments for relevant points.

Referring to fig. 18, fig. 18 is a structural diagram of a network device applied in the embodiment of the present invention, which can implement the details of the method for UE handover and achieve the same effects. As shown in fig. 18, the network device 1000 includes: a processor 1001, a transceiver 1002, a memory 1003, a user interface 1004, and a bus interface, wherein:

in this embodiment of the present invention, the network device 1000 further includes: a computer program stored in the memory 1003 and capable of running on the processor 1001, where the computer program is executed by the processor 1001 to implement the processes of the method for UE handover, and can achieve the same technical effects, and in order to avoid repetition, the details are not described here again.

In fig. 18, the bus architecture may include any number of interconnected buses and bridges, with at least one processor, represented by processor 1001, and various circuits, represented by memory 1003, being linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 1002 may be a number of elements including a transmitter and a receiver that provide a means for communicating with various other apparatus over a transmission medium. The user interface 1004 may also be an interface capable of interfacing with a desired device for different end devices, including but not limited to a keypad, display, speaker, microphone, joystick, etc.

The processor 1001 is responsible for managing a bus architecture and general processes, and the memory 1003 may store data used by the processor 1001 in performing operations.

An embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements each process of the method for UE handover in the above embodiments, and can achieve the same technical effect, and in order to avoid repetition, details are not repeated here. The computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk.

An embodiment of the present invention further provides a computer program product including instructions, and when a computer runs the instructions of the computer program product, the computer executes the method for UE handover. In particular, the computer program product may be run on the network device described above.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the embodiments provided in the present invention, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for UE handover, applied to a source base station, the method comprising:

2. The method of claim 1, wherein there are a plurality of UEs to be handed off connected to the source base station, the method further comprising:

acquiring information related to priority sequencing of the UE to be switched;

generating the priority of the UE to be switched according to the information related to the priority sequence;

determining a switching mode corresponding to the UE to be switched based on the priority of the UE to be switched;

3. The method according to claim 2, wherein the member base stations of the base station cluster can be directly connected through an Xn interface, and the UE handover request also carries identity information of the UE to be handed over;

4. The method of claim 3, wherein if the handover mode is a low interrupt latency handover mode, then

5. The method according to claim 2, characterized in that if member base stations of a base station cluster cannot be directly connected through an Xn interface, and the UE handover request also carries identity information of the UE to be handed over;

6. The method of claim 5, wherein if the handover mode is a low interrupt latency handover mode, then

7. The method according to claim 2, wherein the determining the handover mode corresponding to the UE to be handed over based on the priority of the UE to be handed over comprises:

8. The method according to any one of claims 2 to 7,

the information related to the priority ranking of the UE to be switched comprises at least one of the following information:

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

9. The method according to any of claims 2-7, wherein the base station cluster is constructed in advance according to geographical location information of base stations and load information of base stations.

10. A method for UE handover, applied to a target base station, the method comprising:

11. The method according to claim 10, wherein there are a plurality of UEs to be switched connected to the source base station;

12. The method according to claim 11, wherein the member base stations of the base station cluster can be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over, the method further comprising:

directly sending an identity authentication request aiming at the UE to be switched to the cluster head base station through an Xn interface, wherein the identity authentication request carries identity information of the UE to be switched;

directly receiving a UE identity authentication result from the cluster head base station through an Xn interface, wherein the UE identity authentication result is obtained by authenticating the UE to be switched by the cluster head base station according to the identity information of the UE to be switched from the target base station;

13. The method of claim 12, wherein if the handover mode is a low interrupt latency handover mode, then

14. The method according to claim 12, wherein the member base stations of the base station cluster cannot be directly connected through an Xn interface, and the UE handover request further carries identity information of the UE to be handed over, the method further comprising:

receiving a UE identity authentication result from the cluster head base station through the second interface, wherein the UE identity authentication result is obtained by authenticating the UE to be switched by the cluster head base station according to the identity information of the UE to be switched from the source base station;

15. The method of claim 14, wherein if the target handover mode is a low interrupt latency handover mode, then

16. The method of claim 11,

if the priority of the UE to be switched is the first level, the switching mode corresponding to the UE to be switched is a low interruption time delay switching mode;

17. The method according to any one of claims 11 to 16,

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

18. The method according to any of claims 10-16, wherein the base station cluster is constructed in advance according to geographical location information of base stations and load information of base stations.

19. A method for UE handover, applied to a cluster head base station in a base station cluster, the method comprising:

20. The method of claim 19, further comprising:

and saving the UE information in the base station cluster, wherein the UE information is used for identifying the identity of the UE to be switched.

21. The method of claim 20, further comprising:

acquiring identity information of the UE to be switched;

determining a UE identity authentication result aiming at the UE to be switched according to the identity information of the UE to be switched and the UE information stored in the cluster head base station;

sending the UE identity authentication result to the target base station;

22. The method according to claim 21, wherein the member base stations of the base station cluster can be directly connected through an Xn interface, and the obtaining the identity information of the UE to be handed off includes:

23. The method according to claim 22, wherein if the handover mode corresponding to the UE to be handed over is a low-interruption delay handover mode, then

24. The method of claim 21, wherein the member base stations of the base station cluster are not directly connected via an Xn interface,

the acquiring the identity information of the UE to be switched comprises the following steps:

25. The method according to claim 24, wherein if the handover mode corresponding to the UE to be handed over is a low-interruption delay handover mode, then

26. The method of claim 21,

27. The method of claim 21,

the QoS requirement of the UE to be switched in the communication process;

the service type of the UE to be switched; and

28. The method according to any of claims 19-27, wherein the base station cluster is constructed in advance based on geographical location information of base stations and load information of base stations.

29. The method according to any one of claims 21-27, further comprising:

and if the identity authentication result indicates that the UE to be switched is not the UE in the base station cluster, adding the UE to be switched to the base station cluster, and storing the identity information of the UE to be switched.

30. A network device, applied to a source base station, comprising:

31. A network device, applied to a target base station, comprising:

32. A network device, for use in a cluster head base station in a cluster of base stations, the device comprising:

33. A network device comprising a memory, a processor, and a wireless communication program stored on the memory and executable on the processor, the wireless communication program when executed by the processor implementing the steps of the method of any one of claims 1-29.

34. A computer readable medium having stored thereon a wireless communication program which, when executed by a processor, performs the steps of the method of any of claims 1-29.