CN111212450B

CN111212450B - Switching method and device

Info

Publication number: CN111212450B
Application number: CN201911229654.0A
Authority: CN
Inventors: 李秉肇; 陈燕燕; 亨里克·奥鲁佛松
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2013-09-25
Filing date: 2013-09-25
Publication date: 2024-05-14
Anticipated expiration: 2033-09-25
Also published as: CN104782179B; WO2015042804A1; CN111212450A; CN104782179A

Abstract

The embodiment of the invention discloses a switching method and a switching device. The method comprises the following steps: the method comprises the steps that a first base station sends a switching preparation message of User Equipment (UE) to a second base station, so that the second base station establishes context information of the UE and prepares reserved resources; when the first base station determines that the second base station is required to release the reserved resources, the first base station initiates a resource release instruction to the second base station, instructs the second base station to release the reserved resources, and simultaneously reserves the context information of the UE. It can be seen that, under the instruction of the first base station, the second base station releases the reserved resources but retains the context information of the UE, so that the UE can reconstruct successfully in the second base station, thereby optimizing the handover mode.

Description

Switching method and device

Technical Field

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

Background

In the prior art, for various reasons, how to optimize a handover mode of a User Equipment (UE) from one base station to another is currently under study.

Disclosure of Invention

Accordingly, an objective of the embodiments of the present invention is to provide a handover method and apparatus for solving the above-mentioned problems.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

according to a first aspect of an embodiment of the present invention, there is provided a handover method, an execution body is a first base station, the method including:

Transmitting a handover preparation message of User Equipment (UE) to a second base station, so that the second base station establishes context information of the UE according to the handover preparation message and prepares reserved resources;

and when the second base station is determined to be required to release the reserved resources, initiating a resource release instruction to the second base station, wherein the resource instruction is used for instructing the second base station to release the reserved resources, and simultaneously reserving the context information of the UE.

With reference to the first aspect, in a first possible implementation manner, the resource release indication is carried in a handover cancel message.

With reference to the first aspect, in a second possible implementation manner, the determining that the second base station is required to release the reserved resource includes: and when the UE does not need to immediately initiate the handover to the second base station, determining that the second base station is required to release the reserved resource.

With reference to the first possible implementation manner of the first aspect, in a third possible implementation manner, the carrying includes: the resource release indication occupies a cancel reason field of the handover cancel message in a manner of a specific cancel reason.

With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner, the specific cancellation reason is a non-immediate handover cancellation reason.

With reference to the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner, the resource release indication carries a context release timer length, so that the second base station starts a context release timer according to the context release timer length, and releases the context information of the UE after the context release timer expires.

With reference to the first aspect, or the first possible implementation manner of the first aspect, or the second possible implementation manner of the first aspect, or the third possible implementation manner of the first aspect, or the fourth possible implementation manner of the first aspect, or the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the method further includes:

And after receiving the release UE context notification of the third base station, initiating a switching cancellation message which does not contain the specific cancellation reason to the second base station, so that the second base station releases the context information of the UE according to the switching cancellation message which does not contain the specific cancellation reason.

With reference to the first aspect, or the first possible implementation manner of the first aspect, or the second possible implementation manner of the first aspect, or the third possible implementation manner of the first aspect, or the fourth possible implementation manner of the first aspect, in a seventh possible implementation manner, after receiving a release UE context notification of the third base station, the first base station initiates a handover cancel message that does not include the specific cancel cause to the second base station, and/or the resource release indication initiated by the first base station carries a context release timer length, so that the second base station releases the context information of the UE when a release condition is satisfied; the release condition comprises that a context release timer is overtime, and at least one of a switching cancel message which is initiated by the first base station and does not contain the specific cancel reason is received; the context release timer is started according to the length of the context release timer carried by the resource release indication.

With reference to the first aspect, or the first possible implementation manner of the first aspect, or the second possible implementation manner of the first aspect, or the third possible implementation manner of the first aspect, or the fourth possible implementation manner of the first aspect, or the fifth possible implementation manner of the first aspect, or the sixth possible implementation manner of the first aspect, or the seventh possible implementation manner of the first aspect, in an eighth possible implementation manner, the reserved resource includes at least one of a cell radio network temporary identifier C-RNTI, a dedicated preamble premable, a scheduling request resource, a sounding reference information number resource, and a channel quality indication CQI feedback channel resource.

With reference to the first aspect, or the first possible implementation manner of the first aspect, or the second possible implementation manner of the first aspect, or the third possible implementation manner of the first aspect, or the fourth possible implementation manner of the first aspect, or the fifth possible implementation manner of the first aspect, or the sixth possible implementation manner of the first aspect, or the seventh possible implementation manner of the first aspect, or the eighth possible implementation manner of the first aspect, in a ninth possible implementation manner, the context information includes security context information.

It can be seen that, in the embodiment of the present invention, the second base station releases the reserved resources but simultaneously retains the context information of the UE under the direction of the first base station. The second base station reserves the context information of the UE, so that the UE can be successfully rebuilt in the second base station, and the switching mode is optimized.

According to a second aspect of an embodiment of the present invention, there is provided a handover method, where an execution body is a second base station, the method including:

After receiving a switching preparation message of User Equipment (UE) sent by a first base station, establishing the UE context information according to the switching request and preparing reserved resources;

receiving a resource release instruction sent by the first base station, wherein the resource release instruction is sent by the first base station when the second base station is determined to release the reserved resource;

And according to the resource release indication, releasing the reserved resource and simultaneously reserving the context information of the UE.

With reference to the second aspect, in a first possible implementation manner, the resource release indication is carried in a handover cancel message.

With reference to the first possible implementation manner of the second aspect, in a second possible implementation manner, the carrying includes, in a handover cancel message: the resource release indication occupies a cancel reason field of the handover cancel message in a manner of a specific cancel reason.

With reference to the second possible implementation manner of the second aspect, in a third possible implementation manner, the specific cancellation reason is a non-immediate handover cancellation reason.

With reference to the second aspect, or the first possible implementation manner of the second aspect, or the second possible implementation manner of the second aspect, or the third possible implementation manner of the second aspect, in a fourth possible implementation manner, the method further includes:

And when the release condition is met, releasing the context information of the UE.

With reference to the fourth possible implementation manner of the second aspect, in a fifth possible implementation manner, the release condition includes at least one of a timeout of a context release timer and a reception of a handover cancel message initiated by the first base station and not including the specific cancel reason.

With reference to the fifth possible implementation manner of the second aspect, in a sixth possible implementation manner, the resource release indication carries a context release timer length; the context release timer is started according to the length of the context release timer carried by the resource release indication.

With reference to the fifth possible implementation manner of the second aspect, in a seventh possible implementation manner, the handover cancel message that does not include the specific cancel reason is initiated by the first base station after receiving a release UE context notification of the third base station.

It can be seen that, in this embodiment, specific conditions are configured for the UE, so that the UE may perform handover according to the specific conditions, so that the handover of the UE becomes configurable, thereby optimizing the handover manner.

According to a third aspect of an embodiment of the present invention, there is provided a handover method, including:

Transmitting a switching request message to User Equipment (UE), wherein the switching request message contains switching configuration information, and the switching configuration information comprises a target cell identifier;

And configuring specific conditions for the UE, and notifying the UE so that the UE performs handover for the target cell according to the handover configuration information and the specific conditions.

With reference to the third aspect, in a first possible implementation manner, the handover request message carries a specific condition indication, which is used to instruct the UE to perform handover for the target cell at least when waiting for the specific condition to be met.

With reference to the third aspect, or the first possible implementation manner of the third aspect, in a second possible implementation manner, the handover request message carries the specific condition.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, in a third possible implementation manner, the specific condition includes at least one of a first specific condition, a second specific condition, and a third specific condition;

the first specific condition includes: a radio link failure occurs;

The second specific condition includes: the configured measurement event reaches a trigger condition;

The third specific condition includes: the configured measurement event reaches a trigger condition, and the neighbor cell in the triggered measurement event is the target cell.

With reference to the third aspect, in a fourth possible implementation manner, the handover request message carries a handover cancel timer length, so that the UE starts a handover cancel timer according to the handover cancel timer length.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, or the third possible implementation manner of the third aspect, or the fourth possible implementation manner of the third aspect, in a fifth possible implementation manner, the method further includes:

and when determining that the switching configuration of the UE needs to be canceled, sending a configuration canceling message to the UE.

According to a fourth aspect of an embodiment of the present invention, there is provided a handover method, including:

Receiving a switching request message sent by a base station, wherein the switching request message comprises switching configuration information, and the switching configuration information comprises a target cell identifier;

Receiving a specific condition configured by the base station;

and executing the switching aiming at the target cell according to the switching configuration information and the specific condition.

With reference to the fourth aspect, in a first possible implementation manner, the method further includes: and canceling the switching configuration information when the configuration cancellation condition is satisfied.

With reference to the fourth aspect or the first possible implementation manner of the fourth aspect, in a second possible implementation manner, the configuration cancellation condition includes: the handover cancel timer times out and at least one of a configuration cancel message is received.

With reference to the second possible implementation manner of the fourth aspect, in a third possible implementation manner, the handover request message carries a handover cancel timer length, and the handover cancel timer is started according to the handover cancel timer length.

With reference to the second possible implementation manner of the fourth aspect, in a fourth possible implementation manner, the configuration cancellation message is sent by the base station when it is determined that the handover configuration needs to be cancelled.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, or the fourth possible implementation manner of the fourth aspect, in a fifth possible implementation manner, the handover request message carries a specific condition indication, and is used for executing handover for the target cell when the specific condition is waiting to be met.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, or the fourth possible implementation manner of the fourth aspect, or the fifth possible implementation manner of the fourth aspect, in a sixth possible implementation manner, the handover request message carries the specific condition.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, or the fourth possible implementation manner of the fourth aspect, or the fifth possible implementation manner of the fourth aspect, or the sixth possible implementation manner of the fourth aspect, in a seventh possible implementation manner, the specific condition includes at least one of the first specific condition, the second specific condition, and the third specific condition;

the first specific condition includes: a radio link failure occurs;

According to a fifth aspect of an embodiment of the present invention, there is provided a switching device including:

a first sending unit, configured to send a handover preparation message of a user equipment UE to a second base station, so that the second base station establishes context information of the UE according to the handover preparation message and prepares to reserve resources;

And the second sending unit is used for initiating a resource release instruction to the second base station when the second base station is determined to release the reserved resource, wherein the resource instruction is used for instructing the second base station to release the reserved resource and reserving the context information of the UE.

With reference to the fifth aspect, in a first possible implementation manner, the method further includes:

And the third sending unit is used for initiating a switching cancellation message which does not contain a specific cancellation reason to the second base station after receiving the UE context release notification of the third base station, so that the second base station releases the context information of the UE at least according to the switching cancellation message which does not contain the specific cancellation reason.

According to a sixth aspect of an embodiment of the present invention, there is provided a switching device including:

The establishing unit is used for establishing the UE context information and preparing reserved resources according to the switching preparation information after receiving the switching preparation information of the user equipment UE sent by the first base station;

The first receiving unit is used for receiving a resource release instruction sent by the first base station, wherein the resource release instruction is sent by the first base station when the first base station determines that the second base station is required to release the reserved resource;

and the first releasing unit is used for releasing the reserved resources according to the resource release instruction and reserving the context information of the UE at the same time.

With reference to the sixth aspect, in a first possible implementation manner, the method further includes:

And the second release unit is used for releasing the context information of the UE when the release condition is met.

According to a seventh aspect of an embodiment of the present invention, there is provided a switching device including:

A fourth sending unit, configured to send a handover request message to a UE, where the handover request message includes handover configuration information, where the handover configuration information includes a target cell identifier;

and the configuration unit is used for configuring specific conditions aiming at the UE and notifying the UE so that the UE can execute the switching aiming at the target cell according to the switching configuration information and the specific conditions.

With reference to the seventh aspect, in a first possible implementation manner, the method further includes:

and a fifth sending unit, configured to send a configuration cancellation message to the UE when determining that the handover configuration of the UE needs to be cancelled.

According to an eighth aspect of an embodiment of the present invention, there is provided a switching device including:

a second receiving unit, configured to receive a handover request message sent by a base station, where the handover request message includes handover configuration information, and the handover configuration information includes a target cell identifier;

A third receiving unit configured to receive a specific condition configured by the base station;

And a switching unit, configured to perform switching for the target cell according to the switching configuration information and the specific condition.

With reference to the eighth aspect, in a first possible implementation manner, the method further includes:

and the cancellation unit is used for canceling the switching configuration information when the configuration cancellation condition is met.

With reference to the first possible implementation manner of the eighth aspect, in a second possible implementation manner, the configuration cancellation condition includes: the handover cancel timer times out and at least one of a configuration cancel message is received.

According to a ninth aspect of the embodiment of the present invention, there is provided a switching device including a first CPU, a first memory, and a first transceiver, wherein the first CPU, by running a software program stored in the first memory, invokes data stored in the first memory and invokes the first transceiver, performs at least the following steps:

With reference to the ninth aspect, in a first possible implementation manner, the following steps are further performed:

And after receiving the release UE context notification of the third base station, initiating a switching cancellation message which does not contain a specific cancellation reason to the second base station, so that the second base station releases the UE context information at least according to the switching cancellation message which does not contain the specific cancellation reason.

According to a tenth aspect of the embodiment of the present invention, there is provided a switching device including a second CPU, a second memory, and a second transceiver, wherein the second CPU executes at least the following steps by running a software program stored in the second memory, calling data stored in the second memory, and calling the second transceiver:

receiving a resource release instruction sent by the first base station, wherein the resource release instruction is sent by the first base station when determining that the second base station is required to release the reserved resource;

With reference to the tenth aspect, in a first possible implementation manner, the following steps are further performed:

According to an eleventh aspect of the embodiment of the present invention, there is provided a switching device including a third CPU, a third memory, and a third transceiver, wherein the third CPU, by running a software program stored in the third memory, invokes data stored in the third memory and invokes the third transceiver, performs at least the following steps:

With reference to the eleventh aspect, in a first possible implementation manner, the following steps are further performed:

According to a twelfth aspect of the embodiment of the present invention, there is provided a switching device including a fourth CPU, a fourth memory, and a fourth transceiver, wherein the fourth CPU, by running a software program stored in the fourth memory, invokes data stored in the fourth memory and invokes the fourth transceiver, performs at least the following steps:

Receiving a specific condition configured by the base station;

With reference to the twelfth aspect, in a first possible implementation manner, the following steps are further performed:

and canceling the switching configuration information when the configuration cancellation condition is satisfied.

With reference to the first possible implementation manner of the eleventh aspect, in a second possible implementation manner, the configuration cancellation condition includes: the handover cancel timer times out and at least one of a configuration cancel message is received.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a flowchart of a switching method provided in an embodiment of the present invention;

fig. 2 is another flowchart of a handover method according to an embodiment of the present invention;

FIG. 3 is a flow chart of a multi-preparation handover process according to an embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating energy saving state transition provided in an embodiment of the present invention;

fig. 5 is a schematic diagram of a closed base station according to an embodiment of the present invention;

fig. 6 is a flowchart of an interaction process between a first base station and a second base station according to an embodiment of the present invention;

FIG. 7 is a flowchart of a switching method according to an embodiment of the present invention;

FIG. 8 is a flowchart of a switching method according to an embodiment of the present invention;

Fig. 9 is a flowchart of interaction between a UE and other devices according to an embodiment of the present invention;

Fig. 10 is a schematic structural diagram of a switching device according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of another structure of a switching device according to an embodiment of the present invention;

fig. 12 is a schematic diagram of another structure of a switching device according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of a switching device according to an embodiment of the present invention;

Fig. 14 is a schematic structural diagram of a switching device according to an embodiment of the present invention;

Fig. 15 is a schematic structural diagram of a switching device according to an embodiment of the present invention;

fig. 16 is a schematic diagram of another structure of a switching device according to an embodiment of the present invention;

fig. 17 is a schematic diagram of another structure of a switching device according to an embodiment of the present invention.

Detailed Description

For purposes of reference and clarity, terms, abbreviations or abbreviations used hereinafter are summarized as follows:

C-RNTI: a cell radio network temporary identifier;

Premable: a dedicated preamble;

CQI: channel quality indication.

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

One of the cases where the existing handover scheme needs to be optimized is the handover procedure between base stations. It should be noted that, in order to distinguish between different base stations, the first base station and the second base station may have different roles or definitions in different scenarios, which will be described in detail later herein.

In order to optimize a handover procedure between base stations, an embodiment of the present invention provides a handover method, where an execution body of the handover method may be a first base station or a second base station.

When the execution subject is the first base station, referring to fig. 1, the method at least includes the following steps:

S11, sending a switching preparation message of the UE to a second base station, so that the second base station establishes the context information of the UE according to the switching preparation message and prepares to reserve resources.

The reserved resources may include at least one of C-RNTI, premable, a scheduling request resource, a sounding reference information number resource, and a CQI feedback channel resource. And the context information may include security context information.

The purpose of step S1 is to make the second base station ready for the UE to successfully handover in order to establish the context information of the UE and prepare reserved resources.

And S12, when the second base station is determined to be required to release the reserved resources, initiating a resource release instruction to the second base station, wherein the resource instruction is used for instructing the second base station to release the reserved resources, and meanwhile, the context information of the UE is reserved.

For the second base station, please refer to fig. 2, the steps performed by the second base station may include at least:

S21, after receiving a switching preparation message of the UE, which is sent by a first base station, establishing the UE context information according to the switching request and preparing reserved resources;

S22, receiving a resource release instruction sent by a first base station (the resource release instruction is sent by the first base station when the second base station is determined to release the reserved resource);

s23, according to the resource release instruction, the reserved resources are released, and meanwhile, the context information of the UE is reserved.

The determining the reason for the second base station to release the reserved resource may include: it is determined that the UE does not need to immediately initiate a handover to the second base station.

It should be noted that there are various situations where the UE does not need to immediately initiate a handover to the second base station, which will be described in detail below.

In other embodiments of the present invention, the above-described resource release indication may be carried in a handover cancel message in order to be compatible with existing protocols as much as possible. Of course, other existing messages or newly added messages may be used to carry the resource release instruction, and those skilled in the art may flexibly design the resource release instruction, which is not described herein.

How the resource release indication is carried in the handover cancel message will now be described in detail.

There is a cancel reason field in the handover cancel message, and in the prior art, the cancel reason in the cancel reason field may include a partial handover (indicating that the target can only receive a part of the traffic of the UE, so that the previous handover preparation is canceled). In this embodiment, a specific cancel cause may be newly added. In this way, the resource release indication may occupy the cancel cause field of the handover cancel message described above in a manner that specifies the cancel cause.

More specifically, the above specific cancellation reasons may include a non-immediate handover cancellation reason, or a reserved reestablishment context reason, or other reasons, as long as they do not overlap with the existing cancellation reasons.

As such, the handover cancel message may be divided into two types, one is a handover cancel message including a specific cancel cause and one is a handover cancel message not including a specific cancel cause (i.e., a handover cancel message including an existing cancel cause).

Therefore, after step S11, if a handover cancel message including a specific cause of cancellation is sent to the second base station, the purpose of which is to instruct the second base station to release the reserved resources while preserving the context information of the UE; and if the handover cancel message which does not contain the specific cancel reason is sent to the second base station, the second base station is instructed to release all the reserved resources and the context information of the UE according to the existing mode.

In other steps of other embodiments of the present invention, a handover cancel message that does not include a specific cancel cause will be further referred to, as will be described in detail later herein.

The UE switches between base stations, which can be classified into multi-preparation handover and single-preparation handover. A multi-preparation handover will now be described.

In the existing multi-preparation handover, referring to fig. 3, a source base station (S-eNB) initiates a handover request procedure to a plurality of base stations (base station B, base station C, etc.) in a handover preparation phase. Then one base station (eNB) is selected from the successfully prepared base stations (eNB) (assuming that base station B is selected) as a target base station, and a cell in the base station B is selected as a target cell for handover and transmitted to the UE. After the UE successfully accesses the target cell, the target base station will notify the source eNB. The source eNB then informs the other successfully prepared enbs to release reserved resources and configuration information for the UE.

The benefits of multiple-preparation handover are two: one is that the handover preparation is more reliable, and the handover can continue as long as one eNB returns a handover request success response (i.e., as long as one eNB is ready to succeed). The other is to ensure successful re-establishment by the UE. Currently, in LTE, if UE handover fails, UE may select a cell to initiate RRC connection reestablishment, if the cell receiving the reestablishment request stores security context information of the UE, UE may reestablish successfully, otherwise reestablishment fails. Since the multiple preparations enable the multiple cells (base stations) to store the security context information of the UE, the probability of success in the subsequent initiation of the reestablishment is increased even if the UE fails in handover.

One of the application scenarios for multi-standby switching is power saving state transitions. Referring to fig. 4, there are 7 base stations a to G. When there are fewer users, it may be considered to shut down base station a. After the base station A is closed, referring to FIG. 5,6 base stations from B to G cover the coverage area of the original base station A by enlarging the coverage area, so as to achieve the purpose of saving energy of the base station A.

Since the base station a needs to be turned off, the user in the base station a needs to be handed over to other base stations (cells), but a handover command needs to be transmitted before the base station a (cell) is turned off. Meanwhile, before the base station a is turned off, the coverage of other base stations (cells) is not adjusted. Therefore, the selection of the UE target cell by the base station a may not be very accurate, and may cause the UE handover failure after the coverage change. At this time, using the multi-preparation handover increases the reliability of the handover.

However, the existing multi-standby handover has a drawback: that is, each successfully prepared base station performs resource reservation on the UE, until the UE is successfully handed over, the source base station (base station a) receives a release message sent by the target eNB, and then the source base station sends a handover cancel message to other successfully prepared enbs, and these enbs release the corresponding reserved resources and context information. In fact, after the source eNB selects the target base station and the target cell in the target base station, the resources reserved by other non-target base stations that are ready to succeed are not used. Because these enbs only retain the context information of the UE, the UE can re-establish successfully within the eNB and resources are to be re-allocated during the re-establishment.

The technical scheme provided by the embodiment of the invention can solve the defects, and the reserved resources can be released in advance by utilizing the resource release indication in the embodiment of the invention.

In the case of the multi-standby handover and the energy saving state transition scenario in which the multi-standby handover is applied, the source base station is the first base station, the base stations that are prepared successfully (or called non-target base stations that are prepared successfully) other than the target base station are the second base station, and the target base station may be called the third base station.

In this embodiment, after selecting the target base station and the target cell in the target base station for the UE, the first base station may directly initiate the resource release instruction to other non-target base stations that are ready to succeed without waiting for the notification sent by the target base station.

The interaction flow of the first base station, the second base station, the third base station and the UE may be refer to fig. 6, where the interaction process between the first base station and the second base station is as follows:

(1) The first base station sends a handover request (HO request) to the second base station, wherein the handover request is the handover preparation message;

(2) The second base station generates context information and reserves resources according to the switching request;

(3) The first base station determines that the UE does not need to immediately initiate handover to the second base station and initiates a resource release instruction to the second base station.

The first base station determines that there are a number of situations in which the UE does not need to initiate a handover to the second base station immediately, and under a multi-preparation handover, it may include: other eNB (e.g. a third base station) resource preparation is successful, the first base station decides to initiate handover to other eNB, or the first base station initiates a handover preparation process, but the preparation is performed for preventing the UE from radio link failure and ensuring the success of UE reestablishment.

(4) The first base station initiates a resource release instruction to the second base station, and instructs the second base station to release reserved resources, but reserves UE context information so as to realize successful reconstruction.

(5) And the second base station receives the resource release instruction, releases the reserved resources, and reserves the context information of the UE.

(6) And the second base station releases the context information of the UE when the release condition is met.

More specifically, the release condition may include at least one of a timeout of a context release timer and a receipt of a handover cancel message initiated by the first base station that does not include the specific cancellation reason. Wherein:

The context release timer is started according to the length of the context release timer carried in the resource release instruction. And when the context release timer is overtime, the second base station releases the context information of the UE. Of course, those skilled in the art may also design that the context release timer length is carried in other instructions or messages, or that the context release timer length is a default length, and then the first base station is not required to perform the instruction again.

As for the handover cancel message that does not contain the specific cancel cause, in the multi-preparation handover scenario, the first base station may be initiated after receiving the release UE context notification of the third base station.

That is, after the first base station initiates the resource release instruction to the second base station, if the first base station receives the release UE context notification of the third base station, the first base station will send the above handover cancel message that does not include the specific cancel reason to the second base station.

It should be noted that, one of waiting for the context release timer to expire and waiting for a handover cancel message that does not include a specific cancel cause may be optional. That is, if the select wait context release timer times out, the first base station may not transmit a handover cancel message that does not contain a specific cancel cause; while the second base station may not start the context release timer if it waits for a handover cancel message that does not contain a specific cancel cause. Of course, it is also possible to wait for both the timeout of the context release timer and the handover cancel message that does not contain the specific cause of cancellation, either of which satisfies the context information of the release-immediate UE.

The single preparation handover will be briefly described below. In contrast to a multi-preparation handover, a single-preparation handover involves only the source base station, the target base station, and the UE. In the single preparation handover procedure, there may also be a case where the source base station determines that the UE does not need to initiate handover to the target base station immediately, for example, the source base station initiates the handover preparation procedure only to prevent the UE from radio link failure.

Therefore, the technical scheme provided by the embodiment of the invention is also suitable for a single-preparation switching process. However, in the single preparation handover, the source base station is the first base station, and the target base station is the second base station. The application of the technical solution provided in the embodiment of the present invention in the single-preparation switching scenario is similar to the aforementioned multi-preparation switching scenario, and will not be described herein. In addition, in the single preparation handover scenario, the second base station may release the context information of the UE when the release condition is satisfied. As previously mentioned, the release condition may include at least one of a timeout of a context release timer and a receipt of a handover cancel message initiated by the first base station that does not include a specific cancel cause.

The "handover cancel message not including the specific cause of cancellation" may be initiated to the second base station when the first base station is not ready to be immediately handed over in the single-ready handover scenario.

Next, the second case where the existing handover scheme needs to be optimized will be described herein.

The second case of the existing handover scheme, which requires optimization, is the handover procedure between the UE and the base station. In order to optimize a handover procedure between a UE and a base station, an embodiment of the present invention provides a handover method, where an execution body of the handover method may be the base station or the UE.

When the execution subject is a base station, please refer to fig. 7, which at least can execute the following steps:

And S71, sending a switching request message to the UE.

The handover request message includes handover configuration information, where the handover configuration information includes a target cell identifier.

The handover request message may be specifically a handover command message or an RRC connection reconfiguration message.

S72, configuring specific conditions for the UE, and notifying the UE. So that the UE performs handover for the target cell according to the handover configuration information and the specific condition.

Note that the notification of the specific condition may occur before, after, or simultaneously with the transmission of the handover request message to the UE in time. If simultaneous, one specific implementation is: the handover request message carries the specific conditions described above. Of course, other messages may be used to carry the handover request message, and those skilled in the art may flexibly design the handover request message according to actual needs, which is not described herein.

For the UE, please refer to fig. 8, the steps performed may include at least:

S81, receiving the switching request message sent by the base station;

S82, receiving the specific conditions configured by the base station;

S83, performing handover for the target cell according to the handover configuration information and the specific condition.

Similarly, the specific conditions configured by the receiving base station may occur before, after, or simultaneously with the above-described handover request message sent by the receiving base station. If simultaneous, one specific implementation is: the handover request message carries the specific conditions described above. Of course, other messages may be used to carry the handover request message, and those skilled in the art may flexibly design the handover request message according to actual needs, which is not described herein.

In other embodiments of the present invention, the handover request message in all the embodiments may carry a specific condition indication, which is used to instruct the UE to execute the handover for the target cell when the UE waits for the specific condition to be met. Of course, it may be designed that when the UE receives a specific condition configured by the base station, the UE waits for the specific condition to be satisfied by default, and then performs handover for the target cell. Those skilled in the art can implement flexible designs, and are not described in detail herein.

It should be noted that, the handover optimization of the UE may be applied in the foregoing multi-preparation handover procedure or single-preparation handover procedure. The foregoing also refers to energy saving state transitions, and the handover optimization of the UE is also adapted to energy saving state transitions. In addition, the switching optimization of the UE is also suitable for a scene that the energy-saving state is restored to be normal, a high-speed running scene of the UE and the like.

Taking a scene of restoring the energy saving state to the normal state as an example. It is assumed that it is necessary to restore from the power saving state shown in fig. 5 to the normal state shown in fig. 4, that is, the base station a needs to be turned on. During the recovery process, the coverage areas of base stations B to G shrink and base station a (cell) is opened. At this time, UEs at the edge portions of base stations B to G may need to be handed over to cells under base station a.

But sending a handover request message to the UE needs to be sent before the base stations B to G adjust the coverage area, e.g. after the adjustment, the handover request message may not reach the UE. Whereas the coverage of base station a has not occurred before the coverage area was adjusted. Thus, a contradiction occurs, and the base stations B to G cannot accurately predict which UEs need to be switched and which UEs do not need to be switched. Because normal handover judgment, the UE is required to measure the signal of the base station a first, and judge whether to need to switch to the cell under the base station a according to the measurement result, but the coverage of the base station a is not yet present, so that the judgment is difficult.

The technical scheme provided by the embodiment of the invention can solve the contradiction. The target cell in the handover configuration information may be designated as a cell in the base station a, and a specific condition may be configured to enable the UE to perform handover to the target cell (i.e., a cell in the base station a) when the UE waits for the specific condition to be satisfied.

More specifically, the above-described specific conditions may include at least one of a first specific condition, a second specific condition, and a third specific condition. Wherein:

the first specific condition may include: a radio link failure occurs.

The second specific condition may include: the configured measurement event reaches a trigger condition;

the third specific condition may include: the configured measurement event reaches a trigger condition, and the neighbor cell in the triggered measurement event is the target cell.

It should be noted that, at present, the quality of the signal reported by the UE mainly includes two trigger mechanisms, one of which periodically measures and reports the measurement result, and the other of which reports the measurement result triggered based on the measurement event. There are six total measurement events: A1-A6 are respectively:

event a1: serving becomes better than absolute threshold (Event a1: signal quality of serving cell is greater than absolute threshold);

Event a2: serving becomes worse than absolute threshold (Event a2: signal quality of serving cell is less than absolute threshold);

event a3: neighbour becomes amount of offset better THAN PCELL (Event a3: signal quality of neighbor cell + offset is better than signal quality of primary cell);

event A4: neighbour becomes better than absolute threshold (Event A4: signal quality of neighbor cell is greater than threshold);

Event A5:PCell becomes worse than absolute threshold1 AND Neighbour becomes better than another absolute threshold2( Event A5: the signal quality of the main cell is smaller than the threshold 1, and the signal quality of the neighbor cell is larger than the threshold 2);

Event a6: neighbour becomes amount of offset better THAN SCELL (Event a6: signal quality of neighbor cell + offset is better than signal quality of secondary cell).

While the inter-system measurement events are identified by Bx, e.g., even B1, even B2.

The measurement events involving the neighbor cells include A3-A6, and thus, for a third particular condition, the measurement events that can be selected are any one or any several of A3-A6. And for the second specific condition, the selectable measurement event is any one or any several of A1-A6.

Taking base station B as an example, consider the following case:

In the first case, after the coverage area of the base station B is shrunk, the UE that is located at the edge portion of the base station B may not be located at the edge of the base station B. That is, the UE has a radio link failure. The UE may perform handover for the target cell (i.e., the cell in base station a) when the first specific condition is satisfied, as in the configuration of the specific conditions.

In the second case, the configured specific conditions include a second specific condition or a third specific condition, after the coverage area of the base station B is shrunk, the UE that is located in the edge portion of the base station B may still receive a signal from the cell under the base station B, and the measurement event in the second specific condition or the third specific condition is not triggered. At this time, the UE does not perform handover.

In case three, the specific conditions configured include a second specific condition or a third specific condition, and one or more measurement events are selected in the second specific condition or the third specific condition. After the coverage area of the base station B is contracted, the UE which is originally positioned at the edge part of the base station B can still receive the signals from the cell under the base station B, and meanwhile, the UE can also measure the signals of the cell under the base station A. That is, the cell under base station a is a neighbor cell, and the cell under base station B is a serving cell of the UE. At this time, the UE may perform handover for the target cell (i.e., the cell in the base station a) when the second specific condition or the third specific condition is satisfied.

It can be seen that, due to the introduction of specific conditions, it can be ensured that only UEs requiring handover are handed over. Of course, there may be multiple cases in the handover process in addition to the above three cases, and the diversity of contents included in the specific conditions may enable the handover of the UE to be applicable to the multiple cases.

In other embodiments of the present invention, the UE may cancel the above-described handover configuration information when the configuration cancellation condition is satisfied.

Specifically, the configuration cancellation condition may include: the handover cancel timer times out and at least one of a configuration cancel message is received.

The above-mentioned switching cancellation timer is started by the UE according to the switching cancellation timer length carried in the switching request message. After the handover cancel timer times out, the UE cancels the handover configuration information. Of course, those skilled in the art can also design that the handover cancel timer length is carried in other instructions or messages, or that the handover cancel timer length is a default length, and no further instruction is required by the base station.

As for the configuration cancellation message, the base station may send when determining that the handover configuration needs to be cancelled. The base station determines that the handover configuration needs to be canceled for various reasons, for example, not to prepare for changing the cell coverage, or that the coverage has changed but the UE has not been handed over for a certain time, and so on.

It should be noted that, one of the handover cancel timer timeout and the configuration cancel message may be selected. That is, if it is selected to decide whether to switch according to whether the switch cancel timer has timed out, the base station may not transmit the configuration cancel message; and if the configuration cancel message is selected, the UE may not start the handover cancel timer. Of course, the handover cancel timer timeout and the configuration cancel message may be selected at the same time, and the UE cancels the handover configuration information as long as either one of them is satisfied. A specific way to cancel the handover configuration information may be to clear the handover configuration information described above.

Since the UE needs to perform handover for the target cell according to the handover configuration information and the specific condition, if the handover configuration information is canceled, the UE cannot perform handover for the target cell. That is, when the configuration cancellation condition is not satisfied, if handover configuration information exists and the specific condition is satisfied, the UE performs handover for the target cell. And if the configuration cancellation condition is satisfied, the UE does not perform handover for the target cell.

The interaction flow of the UE with other devices can be seen in fig. 9:

(1) The source eNB sends a handover request message (containing handover configuration information) to the UE indicating a handover target cell.

Meanwhile, optionally, the handover request message may carry the specific condition indication, and instruct the UE to execute the handover for the target cell when the specific condition is met.

Optionally, the source eNB may carry the handover cancel timer length in the handover request message, so that the UE starts the handover cancel timer according to the handover cancel timer.

(2) The UE receives the handover request message and determines whether handover for the target cell is to be performed.

The UE performs handover for the target cell according to the handover configuration information and specific conditions.

The specific conditions may include one or a combination of the following:

first specific conditions: a radio link failure;

If the first specific condition is configured, after the radio link fails, the UE initiates handover to the target cell according to the target cell specified in the handover configuration information.

Second specific condition: the configured measurement event reaches a trigger condition;

Third specific condition: the configured measurement event reaches a trigger condition, and the neighbor cell in the triggered measurement event is the target cell.

If a third specific condition is configured, when the measurement event configured in the third specific condition is A2/3/5 and A2/3/5 triggers, when the neighbor cell is a target cell, triggering the UE to execute handover. After the UE performs handover, a handover confirm message is sent to the target base station.

Optionally, the UE starts a handover cancel timer, and if the timing is timeout and the specific condition is not triggered, the UE cancels the handover configuration information, and does not determine whether to perform handover for the target cell according to the specific condition.

Optionally (3), the source eNB sends a configuration cancellation message to the UE;

In this step, the source eNB determines that the handover configuration information of the UE needs to be canceled, and then sends a configuration cancellation message to the UE, and after receiving the configuration cancellation message, the UE cancels the handover configuration information and does not determine whether to perform handover for the target cell according to a specific condition.

Corresponding to the switching method aiming at the switching flow between the optimized base stations, the embodiment of the invention also provides a switching device.

The switching device may be used as the first base station, and fig. 10 shows a structure of the switching device 100, which may at least include:

A first transmitting unit 1, configured to transmit a handover preparation message of a UE to a second base station, so that the second base station establishes context information of the UE according to the handover preparation message and prepares to reserve resources;

and the second sending unit 2 is configured to initiate a resource release instruction to the second base station when it is determined that the second base station is required to release the reserved resource. The resource indication is used for indicating the second base station to release the reserved resource and simultaneously reserving the context information of the UE.

Please refer to the foregoing descriptions, and the detailed description is omitted herein.

In other embodiments of the present invention, the switching device may further include:

And the third sending unit is used for initiating a switching cancel message which does not contain a specific cancel reason to the second base station after receiving the release UE context notification of the third base station, so that the second base station releases the context information of the UE at least according to the switching cancel message which does not contain the specific cancel reason.

Fig. 11 shows a hardware structure of the switching device 100, which may include a first CPU111, a first memory 112, and a first transceiver 114. Wherein the first transceiver 114 is operable to receive and transmit all data and instructions, the first CPU111 is operable to invoke the data stored in the first memory 112 by running the software program 113 stored in the first memory 112, and the first invoking transceiver 114, at least the following steps are executable:

Transmitting a handover preparation message of the UE to the second base station;

And when the second base station is determined to be required to release the reserved resources, initiating a resource release instruction to the second base station, wherein the resource instruction is used for instructing the second base station to release the reserved resources, and meanwhile, the context information of the UE is reserved.

In addition, the above-mentioned switching apparatus 100 may also perform other steps described in the method section and executable by the first base station, and details of each step are not described herein.

Correspondingly, the embodiment of the invention also provides another switching device. The switching device may act as a second base station. Fig. 12 shows a structure of the switching device 120, which may include at least:

An establishing unit 4, configured to, after receiving a handover preparation message of the UE sent by the first base station, establish the UE context information according to the handover preparation message and prepare to reserve resources;

a first receiving unit 5, configured to receive a resource release instruction sent by a first base station;

a first releasing unit 6, configured to release the reserved resource according to the resource release instruction, while preserving the context information of the UE.

For detailed description of the release condition, please refer to the previous description, and the detailed description is omitted here.

Fig. 13 shows a hardware structure of the switching device 120, which may include a second CPU121, a second memory 122, and a second transceiver 124. Wherein the second transceiver 124 is operable to receive and transmit all data and instructions, the second CPU121, by running the software program 123 stored in the second memory 122, invokes the data stored in the second memory 122, and the second invoking transceiver 124, can perform at least the following steps:

After receiving a handover preparation message of User Equipment (UE) sent by a first base station, establishing the UE context information according to the handover request and preparing reserved resources;

And according to the resource release instruction, releasing the reserved resource and simultaneously reserving the context information of the UE.

In addition, the above-mentioned switching device 120 may also perform other steps described in the method section and executable by the second base station, and details of each step are not described herein.

Corresponding to a handover method for optimizing a handover procedure between a base station and a UE, the embodiment of the present invention further provides a handover apparatus.

Referring to fig. 14, the switching device 140 may include:

A fourth transmitting unit 7, configured to transmit a handover request message to the UE. The switching request message comprises switching configuration information, wherein the switching configuration information comprises a target cell identifier;

a configuration unit 8 configured to configure specific conditions for the UE and notify the UE.

Fig. 15 shows a hardware structure of the switching device 140, which may include a third CPU141, a third memory 142, and a third transceiver 144, where the third CPU141 executes at least the following steps by executing a software program 143 stored in the third memory 142, calling data stored in the third memory 142, and calling the third transceiver 144:

Transmitting a switching request message to the UE, wherein the switching request message comprises switching configuration information, and the switching configuration information comprises a target cell identifier;

And configuring a specific condition for the UE, and notifying the UE so that the UE performs handover for the target cell according to the handover configuration information and the specific condition.

In addition, the above-mentioned handover device 140 may also complete other steps that may be performed by the base station and details of each step described in the handover method section for optimizing the handover procedure between the base station and the UE, which are not described herein.

Correspondingly, the embodiment of the invention also provides another switching device. Fig. 16 shows a structure of the switching device 160, which may include at least:

A second receiving unit 9, configured to receive a handover request message sent by a base station, where the handover request message includes handover configuration information, and the handover configuration information includes a target cell identifier;

A third receiving unit 10 for receiving the specific condition configured by the base station;

a switching unit 11 for performing a handover for the target cell according to the handover configuration information and the specific condition.

For detailed description of the configuration cancellation condition, please refer to the foregoing description, and the detailed description is omitted herein.

Fig. 17 shows a hardware structure of the switching device 160, which may include a fourth CPU161, a fourth memory 162 and a fourth transceiver 164, wherein the fourth CPU161 executes at least the following steps by running a software program stored in the fourth memory 162, calling data stored in the fourth memory 162 and calling the fourth transceiver 164:

receiving the specific conditions configured by the base station;

and executing the switching of the target cell according to the switching configuration information and the specific conditions.

In addition, the above-mentioned switching device 170 may also perform other steps described in the method section herein, which may be performed by the UE, and details of each step are not described herein.

The CPU and the memory in all the embodiments described above may be integrated into the same chip or may be separate two devices.

In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different manner from other embodiments, and the same similar parts of each embodiment are all mutually referred to. The device provided in the embodiment corresponds to the method provided in the embodiment, so that the description is simpler, and the relevant points are just referred to in the method section.

It is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

From the above description of the embodiments, it will be apparent to those skilled in the art that the present invention may be implemented by means of software plus necessary general purpose hardware, including general purpose integrated circuits, general purpose CPUs, general purpose memories, general purpose components, etc., but of course may also be implemented by means of special purpose hardware, including special purpose integrated circuits, special purpose CPUs, special purpose memories, special purpose components, etc., although in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a readable storage medium, such as a U-disc, a removable storage medium, a Read-Only Memory (ROM), a random-access Memory (RAM, random Access Memory), a magnetic disk or an optical disk, or other various media capable of storing software program code, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method of the embodiments of the present invention.

The previous description of the provided embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features provided herein.

Claims

1. A method of handover, comprising:

Transmitting a Radio Resource Control (RRC) connection reconfiguration message to User Equipment (UE), wherein the RRC connection reconfiguration message comprises switching configuration information and switching conditions, the switching configuration information comprises an identifier of a target cell, and the switching conditions are used for indicating conditions that the UE needs to meet when switching to the target cell;

wherein the switching condition includes: the configured measurement event reaches a trigger condition;

The measurement event is: the sum of the signal quality and the offset of the adjacent cell is better than that of the main cell; or the signal quality of the main cell is smaller than the first threshold, and the signal quality of the neighbor cell is larger than the second threshold.

2. The method of claim 1, wherein the handover condition further comprises: and the neighbor cell in the measurement event reaching the triggering condition is the target cell.

3. The method according to claim 1 or 2, further comprising:

And sending a configuration cancellation message to the UE, wherein the configuration cancellation message is used for indicating cancellation of the switching configuration information.

4. The method of claim 3, wherein after canceling the handover configuration information, the UE stops determining whether to handover to the target cell based on the handover condition.

5. A method of handover, comprising:

receiving a Radio Resource Control (RRC) connection reconfiguration message from a base station, wherein the RRC connection reconfiguration message comprises switching configuration information and switching conditions, the switching configuration information comprises an identifier of a target cell, and the switching conditions are used for indicating conditions required to be met by UE (user equipment) to switch to the target cell;

judging whether to switch to the target cell or not according to the switching configuration information and the switching conditions;

6. The method of claim 5, wherein the handoff condition further comprises: and the neighbor cell in the measurement event reaching the triggering condition is the target cell.

7. The method according to claim 5 or 6, further comprising:

and receiving a configuration cancellation message from the base station, wherein the configuration cancellation message is used for indicating cancellation of the switching configuration information.

8. The method of claim 7, wherein the UE stops determining whether to handover to the target cell based on the handover condition after the handover configuration information is cancelled.

9. A switching device, comprising:

A sending unit, configured to send a radio resource control RRC connection reconfiguration message to a user equipment UE, where the RRC connection reconfiguration message includes handover configuration information and a handover condition, where the handover configuration information includes an identifier of a target cell, and the handover condition is used to indicate a condition that needs to be met by the UE to switch to the target cell;

10. The apparatus of claim 9, wherein the handoff condition further comprises: and the neighbor cell in the measurement event reaching the triggering condition is the target cell.

11. The apparatus according to claim 9 or 10, wherein the transmitting unit is further configured to:

12. The apparatus of claim 11, wherein the UE stops determining whether to handover to the target cell based on the handover condition after the handover configuration information is cancelled.

13. A switching device, comprising:

A receiving unit, configured to receive a radio resource control RRC connection reconfiguration message from a base station, where the RRC connection reconfiguration message includes handover configuration information and a handover condition, where the handover configuration information includes an identifier of a target cell, and the handover condition is used to instruct a UE to handover to a condition that needs to be met by the target cell;

a switching unit, configured to determine whether to switch to the target cell according to the switching configuration information and the switching condition;

14. The apparatus of claim 13, wherein the handoff condition further comprises: and the neighbor cell in the measurement event reaching the triggering condition is the target cell.

15. The apparatus according to claim 13 or 14, wherein the receiving unit is further configured to:

16. The apparatus of claim 15, wherein the UE stops determining whether to handover to the target cell based on the handover condition after the handover configuration information is cancelled.

17. A computer readable storage medium storing instructions which, when executed, cause the method according to any one of claims 1 to 4 to be implemented or cause the method according to any one of claims 5 to 8 to be implemented.

18. A switching device, characterized in that it comprises a processor configured to perform the method according to any of claims 1 to 4 or to perform the method according to any of claims 5 to 8.

19. A computer program product, characterized in that it comprises instructions which, when executed, cause the method according to any one of claims 1 to 4 to be implemented or the method according to any one of claims 5 to 8 to be implemented.