CN113825190A

CN113825190A - Communication switching method and device

Info

Publication number: CN113825190A
Application number: CN202110803012.8A
Authority: CN
Inventors: 陈翔; 招溢利
Original assignee: JRD Communication Shenzhen Ltd
Current assignee: JRD Communication Shenzhen Ltd
Priority date: 2017-05-26
Filing date: 2017-05-26
Publication date: 2021-12-21
Anticipated expiration: 2037-05-26
Also published as: CN108934049B; CN108934049A; WO2018214273A1

Abstract

The invention discloses a communication switching method, which comprises the following steps: a source base station receives a measurement report reported by user equipment; the source base station selects a candidate base station for the user equipment according to the measurement report; the source base station sends an automatic switching instruction to the user equipment, wherein the automatic switching instruction comprises information of candidate base stations and switching conditions; the source base station monitors whether a first switching confirmation message reported by user equipment is received; if the first switching confirmation message is received, the transmission in progress is stopped and the subsequent switching process is executed. The invention also discloses a communication switching device. Through the mode, the invention can reduce resource waste and shorten the switching interruption time.

Description

Communication switching method and device

Technical Field

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

Background

Handover is the most fundamental and important procedure in mobility management. In LTE/LTE-a, handover of user equipment is base station controlled. In NR, since a high frequency carrier and a beamforming technique are used, a change in a channel state is fast, which may cause a failure in transmitting a handover command to a user equipment from a source base station, i.e., a base station to which the user equipment is currently connected. Once this occurs, the control signaling between the ue and the base station disappears, and the ue may enter Radio Link Failure (RLF) and perform RRC reestablishment, which results in longer delay.

In order to solve the problem, autonomous handover is proposed, that is, when the channel quality is stable, the source base station sends an early handover command to the ue, where the early handover command includes information of a plurality of candidate base stations and handover conditions, and the ue can perform a handover process when the handover conditions are satisfied.

In the prior art, a source base station cannot timely know whether a user equipment performs autonomous handover, and such a situation may occur: the user equipment has switched to the selected target base station by itself, but the source base station cannot know the message in time, and still sends user data to the user equipment under the condition that the source base station is disconnected from the user equipment, and the user data cannot be successfully received by the user equipment. After the user equipment is successfully switched to the target base station, the target base station needs to resend the part of the user data which is received unsuccessfully, resources occupied by the source base station for sending the user data are wasted, and long switching interruption time (namely time for the user equipment to be incapable of receiving the user data in the switching process) is brought.

Disclosure of Invention

The technical problem mainly solved by the invention is to provide a communication switching method and a communication switching device, which can solve the problems that in the prior art, a source base station cannot timely know whether user equipment performs autonomous switching or not, so that resources are wasted and switching interruption time is long.

In order to solve the above technical problem, a first aspect of the present invention provides a communication handover method, including: a source base station receives a measurement report reported by user equipment; the source base station selects a candidate base station for the user equipment according to the measurement report; the source base station sends an automatic switching instruction to the user equipment, wherein the automatic switching instruction comprises information of candidate base stations and switching conditions; the source base station monitors whether a first switching confirmation message reported by user equipment is received; if the first switching confirmation message is received, the source base station stops the transmission in progress and executes the subsequent switching process.

In order to solve the above technical problem, a second aspect of the present invention provides a communication handover method, including: the user equipment reports a measurement report to a source base station; the user equipment receives an automatic switching instruction from a source base station, wherein the automatic switching instruction comprises information of candidate base stations and switching conditions, and the candidate base stations are selected for the user equipment by the source base station according to a measurement report; the user equipment detects the signal quality of the candidate base station and judges whether the signal quality meets the switching condition; and if so, the user equipment selects the candidate base station meeting the switching condition as a switching target base station, sends a first switching confirmation message to the source base station and executes a switching process.

In order to solve the above technical problem, a third aspect of the present invention provides a communication handover method, including: the candidate base station receives a switching request instruction from the source base station, wherein the switching request instruction comprises information of the user equipment, and the candidate base station is selected for the user equipment by the source base station according to a measurement report reported by the user equipment; the candidate base station executes admission control and judges whether enough resources are available for receiving the user equipment; if the resource is enough, the candidate base station sends a switching preparation confirmation message to the source base station, wherein the switching preparation confirmation message is used for indicating that the admission control is successful; establishing connection between the candidate base station and the user equipment; the candidate base station sends a second handover confirmation message to the source base station.

In order to solve the above technical problem, a fourth aspect of the present invention provides a communication handover method, including: a source base station receives a measurement report reported by user equipment; the source base station selects candidate base stations for the user equipment according to the measurement report, wherein the candidate base stations are divided into at least two levels, the probability that the candidate base stations in different levels are selected by the user equipment as target base stations for switching is different, the completeness of the switching preparation information and/or the switching process corresponding to the candidate base stations in different levels are different, and the higher the probability that the candidate base stations are used as the target base stations is, the higher the completeness of the corresponding switching preparation information is and/or the simpler the switching process is.

In order to solve the above technical problem, a fifth aspect of the present invention provides a communication handover method, including: the user equipment reports a measurement report to a source base station; the user equipment receives an automatic switching instruction from a source base station, the automatic switching instruction comprises information of candidate base stations and switching conditions, the candidate base stations are selected by the source base station for the user equipment according to a measurement report, the candidate base stations are divided into at least two stages, the probability that the candidate base stations in different stages are selected by the user equipment to serve as target base stations for switching is different, the switching preparation information integrity and/or switching processes corresponding to the candidate base stations in different stages are different, and the higher the probability that the candidate base stations serve as the target base stations is, the higher the corresponding switching preparation information integrity and/or the simpler the switching processes are.

In order to solve the above technical problem, a sixth aspect of the present invention provides a communication handover method, including: the candidate base station receives a switching request instruction from a source base station, the switching request instruction comprises information of user equipment, the candidate base station is selected by the source base station for the user equipment according to a measurement report reported by the user equipment, the candidate base station is divided into at least two stages, the candidate base stations in different stages are selected by the user equipment to be used as target base stations for switching in different possibilities, the switching preparation information integrity and/or switching processes corresponding to the candidate base stations in different stages are different, and the higher the possibility that the candidate base station is used as the target base station is, the higher the corresponding switching preparation information integrity and/or the simpler the switching process is.

In order to solve the technical problem, a seventh aspect of the present invention provides a communication switching apparatus, which includes a processor and a communication circuit, wherein the processor is connected with the communication circuit, and the processor is used for executing instructions to implement the method provided by any one of the first to sixth aspects of the present invention.

In order to solve the above technical problem, an eighth aspect of the present invention provides a communication switching apparatus that stores instructions that, when executed, implement the method provided by any one of the first to sixth aspects of the present invention.

In order to solve the above technical problem, a ninth aspect of the present invention provides a communication switching apparatus, including: a receiving module, configured to receive a measurement report reported by a user equipment; a selection module for selecting a candidate base station for the user equipment according to the measurement report; a sending module, configured to send an automatic handover instruction to a user equipment, where the automatic handover instruction includes information of candidate base stations and handover conditions; the monitoring module is used for monitoring whether a first switching confirmation message reported by the user equipment is received or not; if the first switching confirmation message is received, the transmission in progress is stopped and the subsequent switching process is executed.

In order to solve the above-described technical problem, a tenth aspect of the present invention provides a communication switching apparatus comprising: a reporting module, configured to report a measurement report to a source base station; a receiving module, configured to receive an automatic handover instruction from a source base station, where the automatic handover instruction includes information of a candidate base station and a handover condition, and the candidate base station is selected by the source base station for a user equipment according to a measurement report; the detection module is used for detecting the signal quality of the candidate base station and judging whether the signal quality meets the switching condition; and if so, selecting the candidate base station meeting the switching condition as a switching target base station, sending a first switching confirmation message to the source base station and executing a switching process.

In order to solve the above-mentioned technical problem, an eleventh aspect of the present invention provides a communication switching apparatus comprising: a receiving module, configured to receive a handover request instruction from a source base station, where the handover request instruction includes information of a user equipment, and a candidate base station is selected for the user equipment by the source base station according to a measurement report reported by the user equipment; the admission control module is used for executing admission control and judging whether enough resources are available for receiving the user equipment; if the resource is enough, the switching preparation confirmation message is sent to the source base station, and the switching preparation confirmation message is used for indicating that the admission control is successful; the connection module is used for establishing connection with the user equipment; and the sending module is used for sending the second switching confirmation message to the source base station.

In order to solve the above-mentioned technical problem, a twelfth aspect of the present invention provides a communication switching apparatus comprising: a receiving module, configured to receive a measurement report reported by a user equipment; and the selection module is used for selecting the candidate base stations for the user equipment according to the measurement report, wherein the candidate base stations are divided into at least two stages, the probability that the candidate base stations in different levels are selected by the user equipment as the target base stations for switching is different, the switching preparation information integrity and/or the switching process corresponding to the candidate base stations in different levels are different, and the higher the probability that the candidate base stations are used as the target base stations is, the higher the corresponding switching preparation information integrity and/or the simpler the switching process is.

In order to solve the above technical problem, a thirteenth aspect of the present invention provides a communication switching apparatus, comprising: a reporting module, configured to report a measurement report to a source base station; a receiving module, configured to receive an automatic handover instruction from a source base station, where the automatic handover instruction includes information of candidate base stations and handover conditions, and the candidate base stations are selected by the source base station for a user equipment according to a measurement report, where the candidate base stations are divided into at least two levels, the candidate base stations in different levels have different possibilities of being selected by the user equipment as target base stations for handover, the handover preparation information integrity and/or handover procedures corresponding to the candidate base stations in different levels are different, and the higher the possibility of the candidate base station as the target base station is, the higher the integrity of the handover preparation information corresponding to the candidate base station is and/or the simpler the handover procedures are.

In order to solve the above technical problem, a fourteenth aspect of the present invention provides a communication switching apparatus, including: a receiving module, configured to receive a handover request instruction from a source base station, where the handover request instruction includes information of a ue, and the candidate base station is selected by the source base station for the ue according to a measurement report reported by the ue, where the candidate base station is divided into at least two levels, the candidate base stations in different levels have different possibilities of being selected by the ue as target base stations for handover, the integrity and/or handover procedures of handover preparation information corresponding to the candidate base stations in different levels are different, and the higher the possibility of the candidate base station as the target base station is, the higher the integrity and/or the simpler the handover procedure of the handover preparation information corresponding to the candidate base station is.

The invention has the beneficial effects that: the source base station can judge whether the user equipment executes the autonomous switching or not by monitoring whether a first switching confirmation message reported by the user equipment is received or not, if the user equipment executes the autonomous switching, the source base station can confirm the autonomous switching so as to execute a subsequent switching process, and the source base station stops sending user data to the user equipment and forwards the user data to the target base station in the switching process, so that the resource waste is reduced, and the switching interruption time is shortened.

In addition, by ranking the candidate base stations, the candidate base stations with different levels are selected by the user equipment as target base stations for handover with different possibilities, and the higher the possibility that the candidate base station is as the target base station, the higher the integrity of the handover preparation information corresponding to the candidate base station is and/or the simpler the handover process is. The low integrity of the handover preparation information of the candidate base station indicates that less information needs to be transmitted in the handover preparation process, and the handover preparation process is simple, but if the candidate base station is selected as the target base station, the missing part in the handover preparation process needs to be completed in the subsequent handover process, which also brings extra delay and signaling overhead. Because the completeness of the handover preparation information and/or the handover process of the candidate base station is determined according to the probability of the candidate base station as the target base station, the user equipment has the candidate base station which is more likely to be autonomously handed over to the handover preparation information with high completeness and/or the handover process is simple, the signaling overhead in the handover preparation stage of the autonomous handover can be reduced, and the probability of extra delay and signaling overhead in the subsequent handover process can be reduced, so that the signaling overhead of the autonomous handover is reduced, and the real-time performance of the candidate base station is guaranteed.

Drawings

Fig. 1 is a flowchart illustrating a first embodiment of a communication handover method according to the present invention;

FIG. 2 is a flowchart illustrating a second embodiment of a communication handover method according to the present invention;

fig. 3 is a flowchart illustrating that the ue performs autonomous handover within the validity period and the first handover confirm message is successfully received in the second embodiment of the handover method of the present invention;

fig. 4 is a flowchart illustrating that the ue performs autonomous handover within the validity period and the first handover confirm message fails to be received in the second embodiment of the handover method of the present invention;

fig. 5 is a schematic flow chart illustrating that the ue does not perform autonomous handover within the validity period in the second embodiment of the communication handover method of the present invention;

FIG. 6 is a flowchart illustrating a communication handover method according to a third embodiment of the present invention;

fig. 7 is a schematic flowchart illustrating an autonomous handover of a ue to a first-level candidate base station according to a fourth embodiment of the communication handover method of the present invention;

fig. 8 is a schematic flowchart illustrating an autonomous handover of a ue to a second candidate base station in a fourth embodiment of a communication handover method according to the present invention;

fig. 9 is a schematic flowchart illustrating an autonomous handover of a ue to a third candidate base station in a fourth embodiment of a communication handover method according to the present invention;

fig. 10 is a flowchart illustrating a fifth embodiment of the communication handover method according to the present invention;

fig. 11 is a flowchart illustrating a sixth embodiment of a communication handover method according to the present invention;

fig. 12 is a flowchart illustrating an eighth embodiment of a communication handover method according to the present invention;

fig. 13 is a flowchart illustrating a ninth embodiment of the communication handover method according to the present invention;

fig. 14 is a flowchart illustrating an eleventh embodiment of a communication handover method according to the present invention;

fig. 15 is a flowchart illustrating a twelfth embodiment of a communication handover method according to the present invention;

fig. 16 is a schematic flowchart illustrating an autonomous handover of a ue to a first-level candidate base station according to an embodiment of a communication handover method of the present invention;

fig. 17 is a flowchart illustrating an autonomous handover of a ue to a second candidate base station in an embodiment of a communication handover method of the present invention;

fig. 18 is a flowchart illustrating an autonomous handover of a ue to a third candidate base station in an embodiment of a communication handover method according to the present invention;

fig. 19 is a flowchart illustrating a thirteenth embodiment of a communication handover method according to the present invention;

fig. 20 is a flowchart illustrating a fourteenth embodiment of a communication handover method according to the present invention;

fig. 21 is a flowchart illustrating a fifteenth embodiment of a communication handover method according to the present invention;

fig. 22 is a schematic structural diagram of a first embodiment of the communication switching apparatus of the present invention;

fig. 23 is a schematic structural diagram of a second embodiment of the communication switching apparatus of the present invention;

fig. 24 is a schematic structural diagram of a third embodiment of the communication switching apparatus of the present invention;

fig. 25 is a schematic structural diagram of a fourth embodiment of the communication switching apparatus of the present invention;

fig. 26 is a schematic structural diagram of a fifth embodiment of the communication switching apparatus of the present invention;

fig. 27 is a schematic structural diagram of a sixth embodiment of the communication switching apparatus of the present invention;

fig. 28 is a schematic structural diagram of a seventh embodiment of the communication switching apparatus of the present invention;

fig. 29 is a schematic structural view of an eighth embodiment of the communication switching apparatus of the present invention;

fig. 30 is a schematic structural diagram of a ninth embodiment of the communication switching apparatus of the present invention;

fig. 31 is a schematic structural diagram of a tenth embodiment of the communication switching apparatus of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples. Non-conflicting ones of the following embodiments may be combined with each other.

The main execution body of the first embodiment of the communication switching method of the present invention is a base station, and the base station is used as a source base station in the switching process, that is, a base station to which User Equipment (UE) is currently connected. The base station is connected with the core network and performs wireless communication with the user equipment to provide communication coverage for a corresponding geographic area. The base station may be a macro base station, a micro base station, a pico base station, or a home base station (femtocell). In some embodiments, a base station may also be referred to as a radio base station, access point, node B, evolved node B (eNodeB, eNB), gNB, or other suitable terminology.

As shown in fig. 1, the present embodiment includes:

s11: and the source base station receives the measurement report reported by the user equipment.

The reporting of measurement reports may be periodic or aperiodic, for example event triggered. Before this step, the source base station may send a measurement configuration message to the ue for indicating when to start measurement and report a measurement report.

S12: and the source base station selects a candidate base station for the user equipment according to the measurement report.

The measurement report comprises the signal quality of the measurement objects of the user equipment, and the source base station selects a plurality of candidate base stations from the measurement objects according to the signal quality in the measurement report. In addition to the measurement report, the source base station may refer to factors such as the current location of the user equipment, the motion direction, and the load of the candidate base station in selecting the candidate base station.

The source base station may select measurement objects with signal quality greater than a preset threshold as candidate base stations, or may arrange the measurement objects from large to small according to signal quality, and take the first N as candidate base stations, where N is the number of designated candidate base stations. The measurement object may be a base station geographically close to the source base station, or may be a base station from which the source base station can directly obtain information through an interface between the base stations.

S13: and the source base station sends an automatic switching instruction to the user equipment.

The automatic handover command includes information of the candidate base station and handover conditions. The user equipment receiving the automatic handover instruction may prepare for the autonomous handover.

The switching condition in the auto-switching instruction may be a Reference Signal Receiving Power (RSRP) threshold. The handover conditions may be the same or different for different candidate base stations.

S14: the source base station monitors whether a first switching confirmation message reported by the user equipment is received.

S15: if the first switching confirmation message is received, the source base station stops the transmission in progress and executes the subsequent switching process.

After the user equipment selects the target base station, the user equipment firstly sends a first switching confirmation message to the source base station, and then executes autonomous switching to disconnect the connection with the source base station and connect the source base station with the target base station. The target base station is a handover target selected by the user equipment from the candidate base stations. The identity of the target base station may be included in the first handover confirmation message. In the subsequent handover procedure, if the source base station receives user data sent to the user equipment from the core network, the source base station does not send the user data to the user equipment but forwards the user data to the target base station.

Through the implementation of the embodiment, the source base station can judge whether the user equipment performs autonomous handover by monitoring whether the first handover confirmation message reported by the user equipment is received, if the user equipment performs autonomous handover, the source base station can confirm the point in time to perform a subsequent handover process, and the source base station stops sending user data to the user equipment and forwards the user data to the target base station in the handover process, so that the resource waste is reduced, and the handover interruption time is shortened.

As shown in fig. 2, a second embodiment of the communication handover method of the present invention is based on the first embodiment of the communication handover method of the present invention, and a source base station can explicitly/implicitly confirm whether a user equipment performs an autonomous handover. This embodiment is a further extension of the first embodiment of the communication handover method of the present invention, and the same parts are not repeated here, and this embodiment includes:

s101: and the source base station receives the measurement report reported by the user equipment.

S102: and the source base station selects a candidate base station for the user equipment according to the measurement report.

S103: and the source base station sends an automatic switching instruction to the user equipment.

The automatic switching instruction further comprises a validity period. The validity period refers to the validity period of the automatic switching instruction.

In the validity period, if the user equipment executes autonomous handover, a first handover confirmation message is sent to the source base station and then the target base station is switched to; if the autonomous handover is not executed, the UE reports a handover non-execution notification to the source BS at the end of the validity period. The information of the target base station may be included in the first handover confirmation message. The automatic handover command may further include an uplink resource allocated for the non-performed handover notification.

S104: and the source base station monitors whether a first switching confirmation message reported by the user equipment is received or not in the valid period.

If the first switching confirmation message reported by the user equipment is received in the validity period, the user equipment is meant to execute autonomous switching, belongs to the explicit indication, and skips to S105; and if the first switching confirmation message reported by the user equipment is not received at the end of the validity period, skipping to S106.

The source base station may determine whether the validity period is over by using a timer, that is, initializing a timer after sending the automatic handover command to the ue, where an initial value of the timer may be 0/validity period, and the timer may count up and count down respectively, and determine whether the validity period is over by determining whether a current value of the timer is greater than or equal to the validity period/less than or equal to 0. The source base station may also calculate the time when the validity period ends according to the time when the automatic switching instruction is sent and the validity period, and determine whether the validity period ends by determining a magnitude relationship between the current time and the time when the validity period ends. The user equipment may determine whether the validity period is over by using the same method, except that the automatic handover command sent by the source base station is replaced by the automatic handover command received.

S105: the source base station stops the ongoing transmission and performs the subsequent handover procedure.

S106: and the source base station judges whether an unexecuted switching notice reported by the user equipment is received or not when the validity period is over.

The non-performed handover notification may include a non-handover message and/or an updated measurement report.

If the non-performed handover notification is not received, it means that the ue performs the autonomous handover within the validity period, but the change in the radio environment between the source base station and the ue causes the ue not to send the first handover confirm message, or the source base station does not successfully receive the first handover confirm message, implicitly indicates that the autonomous handover has occurred, and then the process goes to step S17. If a non-performed handover notification is received, meaning that the ue does not perform autonomous handover within the validity period, the source base station may evaluate subsequent operations, such as preparing a new automatic handover command and/or reselecting a candidate base station.

S107: the source base station stops the ongoing transmission and buffers the user data, and waits for a second handover confirmation message from the target base station to perform the subsequent handover procedure.

The target base station typically sends a second handover confirm message to the source base station after establishing a connection with the user equipment. Since the source base station does not receive the first handover confirmation message and cannot directly confirm the target base station, the source base station can only buffer the received user data and forward the user data after receiving the second handover confirmation message.

This is illustrated in the following description with reference to the drawings.

As shown in fig. 3, the specific process that the ue performs autonomous handover and the first handover confirm message is successfully received within the validity period includes:

s111: and the source base station receives the measurement report reported by the user equipment.

S112: and the source base station selects a candidate base station for the user equipment according to the measurement report.

S113: and the source base station sends a switching request instruction to the candidate base station.

The handover request command includes information of the ue. And the candidate base station executes admission control, judges whether enough resources receive the user equipment, and if so, sends a switching preparation confirmation message to the source base station, wherein the switching preparation confirmation message is used for indicating that the admission control is successful. And if not, sending a switching preparation negative acknowledgement message to the source base station, wherein the switching preparation negative acknowledgement message is used for indicating that the admission control fails.

S114: the candidate base station sends a handover preparation confirm message to the source base station.

And the candidate base station responds to the switching request instruction to execute admission control, reserves resources for the user equipment if the admission control is successful, and sends a switching preparation confirmation message to the source base station.

S115: and the source base station sends an automatic switching instruction to the user equipment.

The automatic switching instruction comprises the validity period, the information of the candidate base station and the switching condition. If the source base station receives a handover preparation negative acknowledgement message from a candidate base station, the information of the candidate base station is not included in the automatic handover command. The validity period may match the period of reporting measurement reports by the user equipment.

S116: the source base station and the user equipment respectively initialize a timer.

The portion enclosed by a dotted line in the figure indicates the validity period. The timers of the source base station and the user equipment are used for timing the validity period, and the theoretical timing duration is equal to the validity period. In practical application, since the user equipment generally needs time to receive the automatic switching instruction and send the first switching confirmation message, the timing durations of the two timers can be finely adjusted on the basis of the validity period. The period of validity is t₀The time required for the user equipment to receive the automatic switching instruction is t₁The time required for the user equipment to send the first handover confirm message is t₂Time length T of timer of source base station₁Has a value range of [ t₀,t₀+t₁+t₂]Time duration T of timer of user equipment₂Has a value range of [ t₀-t₁-t₂,t₀]And T is₁-T₂＝t₁+t₂。

S117: the user equipment sends a first handover confirmation message to the source base station.

The user equipment decides to execute autonomous handover and sends a first handover confirmation message after selecting the target base station. This step is performed during the expiration period.

S118: and the user equipment is switched to the target base station.

Only one candidate base station selected as the target base station is shown in the figure, and the number of actual candidate base stations may be larger.

As shown in fig. 4, the user equipment performs autonomous handover and fails to receive the first handover confirmation message within the validity period, and the same parts as those in the previous example are not repeated, and the specific process includes:

s121: and the source base station receives the measurement report reported by the user equipment.

S122: and the source base station selects a candidate base station for the user equipment according to the measurement report.

S123: and the source base station sends a switching request instruction to the candidate base station.

S124: the candidate base station sends a handover preparation confirm message to the source base station.

S125: and the source base station sends an automatic switching instruction to the user equipment.

S126: the source base station and the user equipment respectively initialize a timer.

The portion enclosed by a dotted line in the figure indicates the validity period.

S127: the user equipment transmits a first handover confirm message to the source base station but the message reception fails.

This step is performed during the expiration period.

S128: the source base station stops the ongoing transmission and buffers the user data at the end of the validity period.

And the source base station confirms that the user equipment executes autonomous handover and stops sending the user data to the user equipment because the unexecuted handover notification is not received, but cannot know the target base station selected by the user equipment and only can buffer the user data.

S129: and the user equipment and the selected target base station complete synchronization and random access.

S130: and the target base station sends a second switching confirmation message to the source base station.

The target base station may also choose to send a second handover confirmation message to the source base station upon receiving the random access request of the user equipment.

S131: and finishing the switching process.

The handover procedure includes forwarding the buffered user data to the target base station.

As shown in fig. 5, the specific process that the ue does not perform autonomous handover within the validity period includes:

s133: and the source base station receives the measurement report reported by the user equipment.

S134: and the source base station selects a candidate base station for the user equipment according to the measurement report.

S135: and the source base station sends a switching request instruction to the candidate base station.

S136: the candidate base station sends a handover preparation confirm message to the source base station.

S137: and the source base station sends an automatic switching instruction to the user equipment.

S138: the source base station and the user equipment respectively initialize a timer.

The portion enclosed by a dotted line in the figure indicates the validity period. The user equipment does not perform the autonomous handover during the validity period.

S139: and the user equipment sends a non-execution switching notice to the source base station at the end of the validity period.

The source base station determines that the user equipment has not performed an autonomous handover, and may evaluate subsequent operations, such as preparing new automatic handover instructions and/or reselecting a candidate base station.

If there is no validity period and no handover execution notification from the ue, if the ue performs autonomous handover within the validity period but the source base station does not receive the first handover confirmation message, the source base station does not know that the ue performs autonomous handover, and still sends user data to the ue. Through the implementation of the above-mentioned embodiment, even if the source base station cannot receive the first handover confirmation message (for example, in case of deterioration of the wireless environment), it can confirm whether the user equipment performs autonomous handover to perform a subsequent handover procedure in which the source base station stops transmitting user data to the user equipment and forwards it to the target base station according to the fact that the unexecuted handover notification is not received at the end of the validity period, thereby further reducing resource waste and shortening the handover interruption time.

As shown in fig. 6, a third embodiment of the communication handover method according to the present invention is based on the first or second embodiment of the communication handover method according to the present invention, and further includes, after the source base station receives the first/second handover confirm message:

s15: and the source base station sends a resource release message to other candidate base stations which are not selected so as to release the resources reserved for the user equipment.

The source base station can confirm which candidate base station is selected as the target base station by the user equipment according to the first/second switching confirmation message. Since the ue needs to be handed over to the target base station, the other candidate base stations that are not selected do not need to prepare for the handover of the ue, and the source base station may notify the other candidate base stations that are not selected to release the resources reserved for the ue.

A fourth embodiment of the communication handover method according to the present invention is that, based on the first embodiment of the communication handover method according to the present invention, the candidate base stations are divided into at least two stages.

The candidate base stations with different levels are selected by the user equipment as target base stations for switching with different possibilities, and the switching preparation information integrity and/or the switching process corresponding to the candidate base stations with different levels are different. And the higher the possibility that the candidate base station is as the target base station, the higher the integrity of the corresponding handover preparation information and/or the simpler the handover process.

The handover preparation information includes at least one of information of the user equipment in the handover request instruction, information of the candidate base station in the automatic handover instruction, and information of the candidate base station in a handover preparation confirmation message sent by the candidate base station in response to the handover request instruction. The handover preparation information corresponding to the candidate base station is incomplete, the information required to be transmitted during the handover preparation is less, and the handover preparation process is simple, but in the subsequent handover process, the user equipment/the candidate base station serving as the target base station needs to make up the part lacking in the handover preparation process, including the step that the target base station allocates resources for the user equipment and/or acquires the lacking information from the source base station. The lower the integrity of the handover preparation information corresponding to the candidate base station is, the more the user equipment needs to be supplemented when being handed over to the candidate base station, and the more complicated the handover process is.

The source base station needs to evaluate the likelihood of each candidate base station as a target base station to rank the candidate base stations. In the evaluation, in addition to the signal quality of the measurement object in the measurement report, the source base station may refer to the current location of the user equipment, the motion direction, the load of the candidate base station, and the like.

The source base station can select a plurality of candidate base stations from the measurement objects according to the signal quality in the measurement report, and then evaluate the possibility that each candidate base station is used as the target base station; it is also possible to directly evaluate the possibility of each measurement object as a target base station and select a candidate base station based thereon. The source base station may select, as candidate base stations, measurement objects whose signal quality/probability of being a target base station is greater than a preset threshold, or may arrange the measurement objects in descending order of the signal quality/probability of being a target base station, and take the first N as candidate base stations, where N is the number of designated candidate base stations. The measurement object may be a base station geographically close to the source base station, or may be a base station from which the source base station can directly obtain information through an interface between the base stations.

The handover request command and/or the automatic handover command may explicitly/implicitly indicate the rank of the candidate base station. In an explicit case, the handover request command and/or the automatic handover command may further include a rank indicator of the candidate base station, the rank indicator being used to indicate a rank of the candidate base station. Under a recessive condition, the ue/candidate base station may determine the rank of the candidate base station according to the amount of information of the other party in the received automatic handover command/handover request command.

In the prior art, in order to implement autonomous handover, a source base station needs to perform handover preparation with a ue and all candidate base stations, including sending information of the ue required for handover to the candidate base stations to notify the candidate base stations to reserve resources for the ue, and sending information of the candidate base stations required for handover to the ue, which brings a large signaling overhead.

Through the implementation of the embodiment, the candidate base stations are classified, the probability that the candidate base stations in different levels are selected by the user equipment as the target base stations for handover is different, and the higher the probability that the candidate base station is selected as the target base station, the higher the integrity of the corresponding handover preparation information is and/or the simpler the handover process is. The low integrity of the handover preparation information of the candidate base station indicates that less information needs to be transmitted in the handover preparation process, and the handover preparation process is simple, but if the candidate base station is selected as the target base station, the missing part in the handover preparation process needs to be completed in the subsequent handover process, which also brings extra delay and signaling overhead. Because the completeness of the handover preparation information and/or the handover process of the candidate base station is determined according to the probability of the candidate base station as the target base station, the user equipment has the candidate base station which is more likely to be autonomously handed over to the handover preparation information with high completeness and/or the handover process is simple, the signaling overhead in the handover preparation stage of the autonomous handover can be reduced, and the probability of extra delay and signaling overhead in the subsequent handover process can be reduced, so that the signaling overhead of the autonomous handover is reduced, and the real-time performance of the candidate base station is guaranteed.

The following describes the handover preparation information and autonomous handover procedure of candidate base stations of different levels by way of example with reference to the accompanying drawings. In one embodiment of the communication handoff method of the present invention, the candidate base stations are divided into a first level, a second level, and a third level, each represented by candidate base station A, B, C. The same parts in the drawings as those of the previous embodiment are not repeated here.

As shown in fig. 7, the process of autonomous handover of the ue to the first-level candidate base station (candidate base station a) includes:

s141: the source base station sends a measurement configuration message to the user equipment.

S142: and the source base station receives the measurement report reported by the user equipment.

S143: the source base station selects a candidate base station A, B, C for the user equipment.

The candidate base station A is a first stage, the candidate base station B is a second stage, and the candidate base station C is a third stage.

S144: the source base station sends a handover request instruction to the candidate base stations A, B, C, respectively.

The handover request command includes information of the ue. The integrity of the information sent to the user equipment of the candidate base station A, B, C is different.

The handover preparation information of the candidate base station a is complete. The information of the UE included in the handover request command sent to the candidate base station a includes all information required by the first-level candidate base station to complete the normal handover operation on the target side, such AS the complete UE context, Radio bearer information, target Cell ID, eNB/gNB handover transition Key (KeNB/KgNB), RRC context including Cell Radio Network temporary identity (C-RNTI) of the UE at the source base station, Access Stratum (AS) configuration, physical layer ID of the source Cell, short complete Message Authentication Code (MAC-I) for possible Radio Link Failure (RLF) recovery, and so on, wherein the complete UE context at least includes UE X2/Xn signaling reference context/eNB 2/X signaling reference at the source base station UE S1/NG signaling context reference (UE S1/NG signaling context), where X2/Xn is the interface between base stations and S1/NG is the interface between a base station and the core network.

The handover preparation information of the candidate base station B is incomplete. The information of the ue included in the handover request command to the candidate base station B includes the context of the complete ue, radio bearer information, and other necessary information such as the target cell ID.

The handover preparation information integrity of candidate base station C is lower than candidate base station B. The handover request command to the candidate base station C includes only the minimum information of the user equipment, for example, the ID of the user equipment (C-RNTI in the source cell).

S145: the candidate base station A, B, C sends a handover preparation confirm message to the source base station.

After the candidate base station A successfully performs admission control, handover preparation is performed at L1/L2, and a handover preparation acknowledgement message is transmitted to the source base station after allocating resources for the user equipment. The handover preparation information of the candidate base station a is complete, and the information of the resource allocated by the candidate base station a for the user equipment, such as the new C-RNTI allocated for the user equipment, the dedicated random access sequence, and the like, may be included in the handover preparation acknowledgement message as a part of the information of the candidate base station a, or may be independently sent to the source base station and sent by the source base station to the user equipment.

After the candidate base stations B and C successfully perform the admission control, the handover preparation confirmation message is directly sent to the source base station without allocating resources for the user equipment. The handover preparation information of the candidate base stations B and C is incomplete, and the handover preparation acknowledgement messages sent by the candidate base stations B and C do not include information of resources allocated to the user equipment.

S146: and the source base station sends an automatic switching instruction to the user equipment.

The automatic handover command includes information of the candidate base station A, B, C, handover conditions, and validity period.

The handover preparation information of the candidate base station a is complete. The information of the candidate base station a in the automatic handover command includes all the information required for the user equipment to complete the conventional handover, for example, the target cell ID, the handover condition, the new C-RNTI, and the security algorithm identifier of the candidate base station a. In addition, the information of the candidate base station a may further include a dedicated random access sequence, access parameters, system information, and the like. At least part of this information, such as the new C-RNTI assigned by the candidate base station a for the user equipment, the dedicated random access sequence, etc., may be included in the handover preparation confirm message sent by the candidate base station a to the source base station. In general, the information of the resources allocated by the candidate base station a for the user equipment may be included in the handover preparation confirm message sent by the candidate base station a to the source base station.

The handover preparation information of the candidate base stations B and C is incomplete. The information of the candidate base stations B and C in the automatic handover command includes only the information of the minimum candidate base stations, such as the target cell ID and the handover condition.

The information of the candidate base station itself, such as the target cell ID, the security algorithm identifier, etc., may be included in the handover preparation confirm message sent by the candidate base station to the source base station, or may be sent to the source base station periodically or aperiodically.

In this embodiment, the handover condition of each candidate base station is included in the information thereof, and in other embodiments, the handover condition may be independent of the information of the candidate base station, for example, the handover conditions of all candidate base stations are the same.

S147: the user equipment selects the candidate base station a as a target base station for handover.

The user equipment detects the signal quality of the candidate base station and judges whether the candidate base station meets the switching condition. And the detection result shows that the candidate base station A meets the switching condition, and the user equipment selects the candidate base station A as the target base station. Generally, the handover condition is similar to the trigger condition for measurement report reporting in the conventional handover procedure.

S148: the user equipment sends a first handover confirmation message to the source base station.

The first handover confirmation message includes the identity of the target base station, i.e., candidate base station a. S147 and the execution of this step are within the validity period (the portion outlined by the dotted line in the figure).

S149: the source base station transmits a Sequence Number (SN) state transition message to the candidate base station a.

The SN status transition message is used to transfer a Packet Data Convergence Protocol (PDCP) sequence number to notify the candidate base station a of the Data transmission status of the source base station.

S150: the source base station forwards the user data to the candidate base station a.

The user data is user data received by the source base station from the core network for the user equipment. The user equipment performs autonomous handover, the connection with the source base station is disconnected, and the source base station cannot transmit user data to the user equipment, thereby stopping ongoing user data transmission and forwarding the user data.

If the source base station does not receive the user data, this step may not be performed.

S151: the source base station sends a resource release message to the candidate base stations B and C.

The candidate base stations B and C are not selected as handover targets, so the source base station informs it to release the resources reserved for the user equipment. Although the candidate base stations B and C do not allocate resources for the user equipment, context, ID, etc. information of the user equipment may still be retained, which also needs to be released.

The sequence of this step with steps S149 and S152 is merely illustrative, and the sequence may be actually changed or may be executed simultaneously.

S152: the user equipment and the candidate base station A complete synchronization and random access.

S153: the user equipment sends a first handover complete message to the candidate base station a.

S154: the candidate base station a sends a second handover complete message to the source base station.

S155: the source base station releases the resources.

The steps S149-S155 (except for step S151) are the same as the conventional handover procedure, although other handover procedures may be adopted.

As shown in fig. 8, the process of autonomous handover of the ue to the second-level candidate base station (candidate base station B) includes:

s161: the source base station sends a measurement configuration message to the user equipment.

S162: and the source base station receives the measurement report reported by the user equipment.

S163: the source base station selects a candidate base station A, B, C for the user equipment.

S164: the source base station sends a handover request instruction to the candidate base stations A, B, C, respectively.

S165: the candidate base station A, B, C sends a handover preparation confirm message to the source base station.

S166: and the source base station sends an automatic switching instruction to the user equipment.

S167: the user equipment selects the candidate base station B as a target base station for handover.

S168: the user equipment sends a first handover confirmation message to the source base station.

S169: the source base station sends an SN status transition message to the candidate base station B.

S170: the source base station forwards the user data to the candidate base station B.

S171: the source base station sends a resource release message to the candidate base stations a and C.

The candidate base stations a and C are not selected as handover targets, so the source base station informs it to release the resources reserved for the user equipment. The candidate base station a responds to the message to release the resources reserved for the user equipment, including the resources allocated for the user equipment and the information such as the context, ID, etc. of the reserved user equipment. The candidate base station C does not allocate resources to the user equipment, but still retains information such as the ID of the user equipment, which also needs to be released.

The sequence of the step S169 and the step S172 is only an illustration, and the sequence may be actually changed or may be executed simultaneously.

S172: the user equipment and the candidate base station B complete synchronization and random access.

S173: the user equipment and the candidate base station B complete RRC connection reestablishment.

S174: the candidate base station B sends a handover complete message to the source base station.

S175: the source base station releases the resources.

The same or similar parts as in the case of the handover of the user equipment to the candidate base station a are not repeated here.

Since the handover information of the candidate base station B is incomplete, S173 needs to be executed after step S172 to complement the missing part in the handover preparation process. Although the handover information of the candidate base station B is incomplete, the candidate base station B receives the complete context and radio bearer information of the user equipment, so that the candidate base station B can complete the access with the user equipment without acquiring the deficient information from the source base station.

As shown in fig. 9, the process of the ue autonomously switching to the third-class candidate base station (candidate base station C) includes:

s181: the source base station sends a measurement configuration message to the user equipment.

S182: and the source base station receives the measurement report reported by the user equipment.

S183: the source base station selects a candidate base station A, B, C for the user equipment.

S184: the source base station sends a handover request instruction to the candidate base stations A, B, C, respectively.

S185: the candidate base station A, B, C sends a handover preparation confirm message to the source base station.

S186: and the source base station sends an automatic switching instruction to the user equipment.

S187: the user equipment selects the candidate base station C as the target base station for handover.

S188: the user equipment sends a first handover confirmation message to the source base station.

S189: and the source base station sends the SN state conversion message and the deficient information to the candidate base station C.

The missing information at least includes information required for the candidate base station C to synchronize with the ue and perform random access, such as the complete context and radio bearer information of the ue.

The SN state conversion message and the deficient information can be sent simultaneously or sequentially, and the sending sequence is not limited.

S190: the source base station forwards the user data to the candidate base station C.

S191: the source base station sends a resource release message to the candidate base stations a and B.

The candidate base stations a and B are not selected as handover targets, so the source base station informs it to release the resources reserved for the user equipment. The candidate base station a responds to the message to release the resources reserved for the user equipment, including the resources allocated for the user equipment and the information such as the context, ID, etc. of the reserved user equipment. The candidate base station B does not allocate resources for the user equipment, but still retains the context, ID, etc. information of the user equipment, which also needs to be released.

The sequence of the step S189 and the step S192 is only an illustration, and the sequence may be actually changed or may be executed simultaneously.

S192: the user equipment and the candidate base station C complete synchronization and random access.

S193: the user equipment and the candidate base station C complete RRC connection reestablishment.

S194: the candidate base station C sends a handover complete message to the source base station.

S195: the source base station releases the resources.

The same or similar parts as in the case of handover of the user equipment to the candidate base station a/B are not repeated here.

Since the handover information of the candidate base station C is incomplete, the candidate base station C cannot directly complete the access with the user equipment, and therefore, in addition to RRC reestablishment after the access, the candidate base station C needs to acquire the missing information from the source base station before the access.

In the above three examples, the source base station has successfully received the first handover confirmation message from the user equipment, and the actual source base station may also have failed to receive, and at this time, the subsequent handover procedure (for example, sending an SN status transition message, missing information, forwarding user data, etc. to the target base station) at the source base station side needs to be executed after receiving the second handover confirmation message sent by the target base station.

In this embodiment, the candidate base stations are divided into three levels, and the number of levels of the actual candidate base stations is only an integer greater than 1, for example, the candidate base stations may be divided into two levels, where the handover preparation information of one level is complete, the handover preparation information of the other level is incomplete, and the candidate base stations with incomplete handover information at least need to allocate resources to the user equipment in the handover process.

As shown in fig. 10, an execution subject of the fifth embodiment of the communication handover method of the present invention is a base station, and the base station is used as a candidate base station in a handover process, and the embodiment includes:

s21: the candidate base station receives a handover request instruction from the source base station.

The switching request instruction comprises information of the user equipment, and the candidate base station is selected for the user equipment by the source base station according to the measurement report reported by the user equipment.

S22: and the candidate base station executes admission control and judges whether enough resources are available for receiving the user equipment.

S23: if there are enough resources, the candidate base station sends a handover preparation confirm message to the source base station.

The handover preparation confirm message is used to indicate that admission control was successful. In addition, the candidate base station may also choose to allocate resources for the user equipment, and the handover preparation confirm message may include information of the allocated resources, such as a new C-RNTI, a dedicated random access sequence, and the like.

S24: and the candidate base station establishes connection with the user equipment.

In this embodiment, the ue performs autonomous handover, and the candidate base station is selected as the target base station by the ue.

The connection establishment between the candidate base station and the user equipment may refer to the completion of synchronization and random access between the candidate base station and the user equipment, or the reception of a random access request from the user equipment by the candidate base station.

S25: the candidate base station sends a second handover confirmation message to the source base station.

The second handover confirmation message is to inform the source base station which target base station the user equipment selected. When the user equipment executes the autonomous handover, the user equipment reports a first handover confirmation message to the source base station, wherein the first handover confirmation message comprises the identification of the target base station. If the source base station fails to receive the first handover confirmation message, although it may be confirmed that the user equipment performs the autonomous handover according to the non-performed handover notification that is not reported by the user equipment when the validity period of the automatic handover instruction sent to the user equipment is over, it cannot be known which candidate base station is selected by the user equipment as the target base station, and therefore the target base station is required to notify the source base station.

As shown in fig. 11, a sixth embodiment of the communication handover method according to the present invention is based on the fifth embodiment of the communication handover method according to the present invention, and sends a second handover confirmation message when it is confirmed that the source base station has not received the first handover confirmation message. This embodiment is an extension of the fifth embodiment of the communication handover method of the present invention, and therefore the same parts as those are not repeated here. The embodiment comprises the following steps:

s211: the candidate base station receives a handover request instruction from the source base station.

S212: and the candidate base station executes admission control and judges whether enough resources are available for receiving the user equipment.

If the resource is enough, jumping to step S213; if there are not enough resources, the process goes to step S217.

S213: the candidate base station sends a handover preparation confirm message to the source base station.

The source base station may then transmit information of the candidate base stations to the user equipment.

S214: and the candidate base station establishes connection with the user equipment.

S215: and the candidate base station judges whether the SN state conversion message and/or the user data sent by the source base station are received.

If the source base station successfully receives the first handover confirmation message reported by the user equipment, the source base station may directly perform a subsequent handover procedure, including sending an SN status transition message to the target base station, i.e., the candidate base station in this embodiment, and forwarding the user data to the target base station when receiving the user data from the core network.

If the first handover confirmation message is received, the source base station is indicated to have successfully received the first handover confirmation message and execute the subsequent handover process, and the second handover confirmation message does not need to be sent again; if not, it means that the source base station may not successfully receive the first handover confirmation message, and the process skips to step S216.

S216: the candidate base station sends a second handover confirmation message to the source base station.

S217: the candidate base station sends a handover preparation non-acknowledgement message to the source base station.

And ending the flow. The handover preparation non-acknowledgement message is used to indicate that the admission control fails, and then the source base station will remove the execution subject of the embodiment from the candidate base station.

A seventh embodiment of the communication handover method according to the present invention is that, based on the fifth embodiment of the communication handover method according to the present invention, the candidate base stations are divided into at least two stages.

The candidate base stations with different levels are selected by the user equipment as target base stations for switching with different possibilities, the switching preparation information integrity and/or switching processes corresponding to the candidate base stations with different levels are different, and the higher the possibility that the candidate base station is used as the target base station is, the higher the corresponding switching preparation information integrity and/or the simpler the switching process is.

The handover preparation information corresponding to the candidate base station is incomplete, the information required to be transmitted during the handover preparation is less, and the handover preparation process is simple, but in the subsequent handover process, the user equipment/the candidate base station serving as the target base station needs to make up the part lacking in the handover preparation process, including the step that the target base station allocates resources for the user equipment and/or acquires the lacking information from the source base station. The lower the integrity of the handover preparation information corresponding to the candidate base station is, the more the user equipment needs to be supplemented when being handed over to the candidate base station, and the more complicated the handover process is.

The handover preparation information and the handover procedure of the candidate base stations of different levels can refer to the fourth embodiment of the communication handover method and the description in the example thereof, and are not repeated here.

The main executing body of the eighth embodiment of the method for switching communication in the present invention is the user equipment, which may be fixed or mobile, and may be a cellular phone, a Personal Digital Assistant (PDA), a wireless modem, a tablet computer, a notebook computer, a cordless phone, etc. As shown in fig. 12, the present embodiment includes:

s31: and the user equipment reports the measurement report to the source base station.

The reporting of measurement reports may be periodic or aperiodic, for example event triggered. Before this step, the ue may receive a measurement configuration message from the source bs to indicate when to start measurement and report a measurement report.

S32: the user equipment receives an automatic handover command from the source base station.

The automatic handover command includes information of candidate base stations and handover conditions, and the candidate base stations are selected by the source base station for the user equipment according to the measurement report. The switching condition in the auto-switching instruction may be a Reference Signal Receiving Power (RSRP) threshold. The handover conditions may be the same or different for different candidate base stations.

S33: the user equipment detects the signal quality of the candidate base station and judges whether the signal quality meets the switching condition.

S34: and if so, the user equipment selects the candidate base station meeting the switching condition as a switching target base station, sends a first switching confirmation message to the source base station and executes a switching process.

If the number of the candidate base stations meeting the switching condition is only one, the user equipment can directly select the candidate base station as a target base station; if the number of candidate base stations satisfying the handover condition is greater than one, the user equipment may select one of the candidate base stations as the target base station according to a predetermined rule, such as the best signal quality.

The identity of the target base station may be included in the first handover confirmation message.

As shown in fig. 13, a ninth embodiment of the communication handover method according to the present invention is a communication handover method according to the eighth embodiment of the present invention, wherein the ue sends a handover non-execution notification to the source base station when the autonomous handover is not executed. This embodiment is a further extension of the eighth embodiment of the communication handover method of the present invention, and the same parts are not repeated here, and this embodiment includes:

s301: and the user equipment reports the measurement report to the source base station.

S302: the user equipment receives an automatic handover command from the source base station.

The auto-switching instruction further includes a validity period. The validity period refers to the validity period of the automatic switching instruction. The automatic handover command may further include an uplink resource allocated for the non-performed handover notification.

S303: the user equipment detects the signal quality of the candidate base station in the valid period and judges whether the candidate base station meets the switching condition.

The ue may use a timer to determine whether the validity period is over, that is, initialize a timer after receiving the automatic switching instruction, where the initial value of the timer may be 0/validity period, corresponding to count up and count down, respectively, and determine whether the validity period is over by determining whether the current value of the timer is greater than or equal to the validity period/less than or equal to 0. The user equipment can also calculate the end time of the validity period according to the time of receiving the automatic switching instruction and the validity period, and judge whether the validity period is ended by judging the size relationship between the current time and the end time of the validity period.

If the candidate base station meeting the switching condition is found in the valid period, jumping to step S304; if no candidate base station satisfying the handover condition is found at the end of the validity period, the process goes to step S305.

S304: the user equipment selects the candidate base station meeting the switching condition as a switching target base station, sends a first switching confirmation message to the source base station and executes a switching process.

S305: and the user equipment reports the notice of the non-execution switching to the source base station.

The source base station may evaluate subsequent operations, such as preparing new automatic handover instructions and/or reselecting candidate base stations, based on the non-performed handover notification.

In addition, if the user equipment performs an autonomous handover but the handover fails, the user equipment may re-evaluate signal qualities of cells of the source base station and the candidate base station and select a cell having the best signal quality therefrom.

If the selected cell is the source cell to which the user equipment is originally connected, the user equipment may attempt to continue the RRC connection with the source cell because the source base station still maintains the context of the user equipment. If the selected cell is the cell of the candidate base station, the user equipment may attempt to connect with the candidate base station using an RRC connection reconfiguration or reestablishment procedure according to the level of the candidate base station. If none of the cells with the best signal quality can meet the access requirement of the user equipment, the user equipment can enter an idle state to perform cell reselection and then try to connect to the reselected cell.

Specific examples may refer to the description of the second embodiment of the communication handover method used in the present invention, and will not be repeated here.

A tenth embodiment of the communication handover method according to the present invention is a communication handover method according to the eighth embodiment of the present invention, wherein the candidate base stations are divided into at least two stages.

As shown in fig. 14, the executing subject of the eleventh embodiment of the communication handover method of the present invention is the base station, and the base station is used as the source base station in the handover process. The embodiment comprises the following steps:

s41: and the source base station receives the measurement report reported by the user equipment.

S42: the source base station selects candidate base stations for the user equipment according to the measurement report, wherein the candidate base stations are divided into at least two levels.

Through the implementation of the embodiment, the candidate base stations are classified, the candidate base stations in different grades are selected by the user equipment to be different in probability as the target base station for handover, and the higher the probability that the candidate base station is as the target base station, the higher the integrity of the corresponding handover preparation information is and/or the simpler the handover process is. The low integrity of the handover preparation information of the candidate base station indicates that less information needs to be transmitted in the handover preparation process, and the handover preparation process is simple, but if the candidate base station is selected as the target base station, the missing part in the handover preparation process needs to be completed in the subsequent handover process, which also brings extra delay and signaling overhead. Because the completeness of the handover preparation information and/or the handover process of the candidate base station is determined according to the probability of the candidate base station as the target base station, the user equipment has the candidate base station which is more likely to be autonomously handed over to the handover preparation information with high completeness and/or the handover process is simple, the signaling overhead in the handover preparation stage of the autonomous handover can be reduced, and the probability of extra delay and signaling overhead in the subsequent handover process can be reduced, so that the signaling overhead of the autonomous handover is reduced, and the real-time performance of the candidate base station is guaranteed.

As shown in fig. 15, a twelfth embodiment of the communication switching method according to the present invention is the eleventh embodiment of the communication switching method according to the present invention, and further includes, after step S42:

s43: and the source base station sends a switching request instruction to the candidate base station.

S44: and the source base station receives a switching preparation confirmation message sent by the candidate base station in response to the switching request instruction.

S45: and the source base station sends an automatic switching instruction to the user equipment.

The automatic handover command includes information of the candidate base station and handover conditions. The handover condition in the automatic handover instruction may be an RSRP threshold. The handover conditions may be the same or different for different candidate base stations.

The handover preparation information includes at least one of information of the user equipment in the handover request instruction, information of the candidate base station in the automatic handover instruction, and information of the candidate base station in a handover preparation confirmation message sent by the candidate base station in response to the handover request instruction. The ue/candidate bs receiving the automatic handover command/handover request command may prepare for autonomous handover. The handover preparations made by the candidate base stations of different levels may be different, the more complete the handover preparation of the candidate base station with the higher probability as the target base station.

As shown in fig. 16, the process of autonomous handover of the user equipment to the first-level candidate base station (candidate base station a) includes:

s411: the source base station sends a measurement configuration message to the user equipment.

S412: and the source base station receives the measurement report reported by the user equipment.

S413: the source base station selects a candidate base station A, B, C for the user equipment.

S414: the source base station sends a handover request instruction to the candidate base stations A, B, C, respectively.

The handover preparation information of the candidate base station a is complete. The information of the user equipment included in the handover request command to the candidate base station a includes all the information required by the first-level candidate base station to complete the normal handover operation on the target side, e.g. the context of the complete user equipment, radio bearer information, target cell ID, KeNB/KgNB, RRC context at the source base station including the C-RNTI of the user equipment, AS configuration, physical layer ID of the source cell, short MAC-I for possible RLF recovery etc., wherein the context of the complete user equipment comprises at least a UE X2/Xn signaling context reference at the source base station (UE X2/Xn signaling context reference at source eNB), a UE S1/NG signaling context reference (UE S1/NG signaling context reference), wherein X2/Xn is the interface between the base stations, and S1/NG is the interface between the base stations and the core network.

S415: the candidate base station A, B, C sends a handover preparation confirm message to the source base station.

The candidate base station A performs handover preparation at L1/L2, and transmits a handover preparation confirm message to the source base station after allocating resources for the user equipment. The handover preparation information of the candidate base station a is complete, and the information of the resource allocated by the candidate base station a for the user equipment, such as the new C-RNTI allocated for the user equipment, the dedicated random access sequence, and the like, may be included in the handover preparation acknowledgement message as the information of the candidate base station a, or may be independently sent to the source base station and sent to the user equipment by the source base station.

The candidate base stations B and C directly transmit a handover preparation confirm message to the source base station without allocating resources for the user equipment after performing the access control. The handover preparation information of the candidate base stations B and C is incomplete, and the handover preparation acknowledgement messages sent by the candidate base stations B and C do not include information of resources allocated to the user equipment.

S416: and the source base station sends an automatic switching instruction to the user equipment.

The automatic handover command includes information of the candidate base station A, B, C and handover conditions.

S417: the user equipment selects the candidate base station a as a target base station for handover.

S418: the user equipment sends a handover confirm message to the source base station.

The handover confirmation message includes the identity of the target base station, i.e., candidate base station a.

S419: the source base station sends an SN status transition message to the candidate base station a.

The SN status transition message is used to deliver a PDCP sequence number to inform the candidate base station a of the data transmission status of the source base station.

S420: the source base station forwards the user data to the candidate base station a.

S421: the source base station sends a resource release message to the candidate base stations B and C.

The sequence of the step S419 is only illustrative, and the sequence may be actually changed or may be executed simultaneously.

S422: the user equipment and the candidate base station A complete synchronization and random access.

S423: the user equipment sends a first handover complete message to the candidate base station a.

S424: the candidate base station a sends a second handover complete message to the source base station.

S425: the source base station releases the resources.

The steps S419-S425 (except for step S421) are the same as the conventional handover procedure, although other handover procedures may be employed.

In this example, the source base station confirms that the user equipment has performed autonomous handover by receiving a handover confirmation message from the user equipment, and the actual source base station may also confirm in other manners.

As shown in fig. 17, the process of autonomous handover of the ue to the second-level candidate base station (candidate base station B) includes:

s431: the source base station sends a measurement configuration message to the user equipment.

S432: and the source base station receives the measurement report reported by the user equipment.

S433: the source base station selects a candidate base station A, B, C for the user equipment.

S434: the source base station sends a handover request instruction to the candidate base stations A, B, C, respectively.

S435: the candidate base station A, B, C sends a handover preparation confirm message to the source base station.

S436: and the source base station sends an automatic switching instruction to the user equipment.

S437: the user equipment selects the candidate base station B as a target base station for handover.

S438: the user equipment sends a handover confirm message to the source base station.

S439: the source base station sends an SN status transition message to the candidate base station B.

S440: the source base station forwards the user data to the candidate base station B.

S441: the source base station sends a resource release message to the candidate base stations a and C.

The sequence of the step S439 and the step S442 is only illustrated, and the sequence may be actually changed or may be executed simultaneously.

S442: the user equipment and the candidate base station B complete synchronization and random access.

S443: the user equipment and the candidate base station B complete RRC connection reestablishment.

S444: the candidate base station B sends a handover complete message to the source base station.

S445: the source base station releases the resources.

Since the handover information of the candidate base station B is incomplete, S443 needs to be executed after step S442 to acquire the missing information. Although the handover information of the candidate base station B is incomplete, the candidate base station B receives the complete context and radio bearer information of the user equipment, so that the candidate base station B can complete the access with the user equipment without acquiring the deficient information from the source base station.

In other embodiments, the ue and the candidate bs B may obtain the missing information from the source bs and then perform the conventional handover procedure.

As shown in fig. 18, the process of the user equipment autonomously switching to the third-class candidate base station (candidate base station C) includes:

s451: the source base station sends a measurement configuration message to the user equipment.

S452: and the source base station receives the measurement report reported by the user equipment.

S453: the source base station selects a candidate base station A, B, C for the user equipment.

S454: the source base station sends a handover request instruction to the candidate base stations A, B, C, respectively.

S455: the candidate base station A, B, C sends a handover preparation confirm message to the source base station.

S456: and the source base station sends an automatic switching instruction to the user equipment.

S457: the user equipment selects the candidate base station C as the target base station for handover.

S458: the user equipment sends a handover confirm message to the source base station.

S459: and the source base station sends the SN state conversion message and the deficient information to the candidate base station C.

The SN state and the deficient information can be sent simultaneously or sequentially, and the sending sequence is not limited.

S460: the source base station forwards the user data to the candidate base station C.

S461: the source base station sends a resource release message to the candidate base stations a and B.

The sequence of the step S459 and the step S462 is only an illustration, and the sequence may be actually changed or may be executed simultaneously.

S462: the user equipment and the candidate base station C complete synchronization and random access.

S463: the user equipment and the candidate base station C complete RRC connection reestablishment.

S464: the candidate base station C sends a handover complete message to the source base station.

S465: the source base station releases the resources.

In this embodiment, the candidate base stations are divided into three levels, and the number of levels of the actual candidate base stations is only an integer greater than 1, for example, the candidate base stations may be divided into two levels, where the handover preparation information of one level is complete, the handover preparation information of the other level is incomplete, and the candidate base stations with incomplete handover information at least need to obtain the missing information from the user equipment in the handover process.

As shown in fig. 19, the main execution body of the thirteenth embodiment of the communication handover method of the present invention is a base station, and the base station is used as a candidate base station in the handover process, and the embodiment includes:

s51: the candidate base station receives a handover request instruction from the source base station.

The handover request instruction comprises information of the user equipment, the candidate base stations are selected for the user equipment by the source base station according to the measurement report reported by the user equipment, the candidate base stations are divided into at least two levels, the probability that the candidate base stations in different levels are selected by the user equipment as the target base stations for handover is different, the completeness of the handover preparation information and/or the handover flow corresponding to the candidate base stations in different levels is different, and the higher the probability that the candidate base station is used as the target base station is, the higher the completeness of the handover preparation information corresponding to the candidate base station is and/or the simpler the handover flow is.

The handover request command may explicitly or implicitly indicate the rank of the candidate base station, and the handover preparation information and the handover procedure of the candidate base stations of different ranks may refer to the description of the twelfth embodiment of the communication handover method and the examples thereof in the present invention, which is not repeated here.

As shown in fig. 20, a fourteenth embodiment of the communication handover method according to the present invention is the communication handover method according to the thirteenth embodiment of the present invention, and further includes, after S51:

s52: and the candidate base station establishes connection with the user equipment to execute admission control and judge whether enough resources are available for receiving the user equipment.

If the resources are enough, jumping to step S53; if there are not enough resources, the process goes to step S54.

The candidate base station sends a handover preparation confirm message to the source base station S53.

The handover preparation confirm message is used to indicate that admission control was successful. The candidate base station may reserve resources for the source base station according to its own level.

The source base station then transmits information of the candidate base stations to the user equipment. Then if the candidate base station is selected as the target base station, the subsequent switching process can be executed; if not, the reserved resources may be released.

S54: the candidate base station sends a handover preparation non-acknowledgement message to the source base station.

The handover preparation negative acknowledgement message is used to indicate an admission control failure. The source base station does not then transmit information of the candidate base station to the user equipment.

The executing body of the fifteenth embodiment of the method for switching communication in the present invention is the user equipment, which may be fixed or mobile, and may be a cellular phone, a Personal Digital Assistant (PDA), a wireless modem, a tablet computer, a notebook computer, a cordless phone, etc. As shown in fig. 21, the present embodiment includes:

s61: and the user equipment reports the measurement report to the source base station.

S62: the user equipment receives an automatic handover command from the source base station.

The automatic switching instruction comprises information of candidate base stations and switching conditions, the candidate base stations are selected by a source base station for user equipment according to a measurement report, the candidate base stations are divided into at least two levels, the probability that the candidate base stations in different levels are selected by the user equipment as target base stations for switching is different, the switching preparation information integrity and/or switching processes corresponding to the candidate base stations in different levels are different, and the higher the probability that the candidate base station is used as the target base station is, the higher the corresponding switching preparation information integrity and/or the simpler the switching process is.

The automatic handover command may explicitly or implicitly indicate the rank of the candidate base station, and the handover preparation information and the handover procedure of the candidate base stations of different ranks may refer to the description of the twelfth embodiment of the communication handover method and the examples thereof, which are not repeated herein.

As shown in fig. 22, the first embodiment of the communication switching apparatus of the present invention includes: processor 110 and communication circuit 120, communication circuit 120 is connected to processor 110.

The communication circuit 120 is used for transmitting and receiving user data, and is an interface for the communication switching apparatus to communicate with other communication devices.

The processor 110 controls the operation of the communication switching device, and the processor 110 may also be referred to as a Central Processing Unit (CPU). The processor 110 may be an integrated circuit chip having signal processing capabilities. The processor 110 may also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The processor 110 is configured to execute the instructions to implement the method provided by any one of the first to seventh, eleventh to fourteenth embodiments of the communication switching method of the present invention and any non-conflicting combinations.

The communication switching device in this embodiment may be a base station, or may be a separate component, such as a baseband board, that may be integrated into the base station.

As shown in fig. 23, the second embodiment of the communication switching apparatus of the present invention includes: processor 210 and communication circuit 220, communication circuit 220 is connected to processor 210.

The communication circuit 220 is used for transmitting and receiving user data, and is an interface for the communication switching device to communicate with other communication apparatuses.

The processor 210 controls the operation of the communication switching device, and the processor 110 may also be referred to as a Central Processing Unit (CPU). The processor 110 may be an integrated circuit chip having signal processing capabilities. The processor 110 may also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The processor 210 is configured to execute the instructions to implement the method provided by any one of the eighth to tenth and fifteenth embodiments of the communication handover method of the present invention and any non-conflicting combination.

The communication switching device in this embodiment may be a user equipment, or may be a separate component, such as a baseband chip, that may be integrated in the user equipment.

As shown in fig. 24, the third embodiment of the communication switching apparatus of the present invention includes a memory 310, and the memory 310 stores instructions that, when executed, implement the method provided by any one of the first to seventh, eleventh to fourteenth embodiments of the communication switching method of the present invention and any non-conflicting combinations.

The Memory 310 may include a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a hard disk, an optical disk, and the like.

As shown in fig. 25, the fourth embodiment of the communication switching apparatus of the present invention includes a memory 410, and the memory 410 stores instructions that, when executed, implement the method provided by any one of the eighth to tenth embodiments and the fifteenth embodiment of the communication switching method of the present invention, and any non-conflicting combination.

The Memory 410 may include a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a hard disk, an optical disk, and the like.

As shown in fig. 26, a fifth embodiment of the communication switching apparatus of the present invention includes:

a receiving module 11, configured to receive a measurement report reported by a user equipment.

A selecting module 12, configured to select a candidate base station for the ue according to the measurement report.

A sending module 13, configured to send an automatic handover instruction to the ue, where the automatic handover instruction includes information of the candidate base station and a handover condition.

The monitoring module 14 is configured to monitor whether a first handover confirmation message reported by the user equipment is received; if the first switching confirmation message is received, the transmission in progress is stopped and the subsequent switching process is executed.

As shown in fig. 27, a sixth embodiment of the communication switching apparatus of the present invention includes:

a reporting module 21, configured to report a measurement report to the source base station.

A receiving module 22, configured to receive an automatic handover instruction from the source base station, where the automatic handover instruction includes information of candidate base stations and handover conditions, and the candidate base stations are selected by the source base station for the ue according to the measurement report.

A detecting module 23, configured to detect signal quality of the candidate base station and determine whether it meets a handover condition; and if so, selecting the candidate base station meeting the switching condition as a switching target base station, sending a first switching confirmation message to the source base station and executing a switching process.

As shown in fig. 28, the seventh embodiment of the communication switching apparatus of the present invention includes:

a receiving module 31, configured to receive a handover request instruction from a source base station, where the handover request instruction includes information of a ue, and a candidate base station is selected for the ue by the source base station according to a measurement report reported by the ue.

An admission control module 32, configured to perform admission control and determine whether there are enough resources to receive the user equipment; and if the resource is enough, sending a switching preparation confirmation message to the source base station, wherein the switching preparation confirmation message is used for indicating that the admission control is successful.

A connection module 33, configured to establish a connection with the user equipment.

A sending module 34, configured to send a second handover confirmation message to the source base station.

As shown in fig. 29, an eighth embodiment of the communication switching apparatus of the present invention comprises:

a receiving module 41, configured to receive a measurement report reported by a user equipment;

a selecting module 42, configured to select candidate base stations for the ue according to the measurement report, where the candidate base stations are divided into at least two levels, the candidate base stations in different levels have different probabilities of being selected by the ue as target base stations for handover, the handover preparation information integrity and/or handover procedures corresponding to the candidate base stations in different levels are different, and the higher the probability that the candidate base station is used as the target base station is, the higher the corresponding handover preparation information integrity and/or the simpler the handover procedures are.

As shown in fig. 30, a ninth embodiment of the communication switching apparatus of the present invention comprises:

a reporting module 51, configured to report a measurement report to a source base station;

a receiving module 52, configured to receive an automatic handover instruction from a source base station, where the automatic handover instruction includes information of candidate base stations and handover conditions, and the candidate base stations are selected by the source base station for a user equipment according to a measurement report, where the candidate base stations are divided into at least two levels, the candidate base stations in different levels are selected by the user equipment as target base stations for handover with different possibilities, the integrity of handover preparation information and/or handover procedures corresponding to the candidate base stations in different levels are different, and the higher the probability that the candidate base station is used as the target base station is, the higher the integrity of the handover preparation information corresponding to the candidate base station is and/or the simpler the handover procedures are.

As shown in fig. 31, a tenth embodiment of the communication switching apparatus of the present invention includes:

a receiving module 61, configured to receive a handover request instruction from a source base station, where the handover request instruction includes information of a ue, and the candidate base station is selected by the source base station for the ue according to a measurement report reported by the ue, where the candidate base stations are divided into at least two levels, the candidate base stations in different levels are selected by the ue as target base stations for handover with different possibilities, the integrity of handover preparation information and/or handover procedures corresponding to the candidate base stations in different levels are different, and the higher the probability that the candidate base station is used as the target base station is, the higher the integrity of the handover preparation information corresponding to the candidate base station is and/or the simpler the handover procedures are.

The functions and possible extensions of each part in each embodiment of the communication switching apparatus of the present invention may specifically refer to the description in the corresponding embodiment of the communication switching method of the present invention, and are not repeated here.

In the embodiments provided in the present invention, it should be understood that the disclosed method and apparatus can be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the modules or 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 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 integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit 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 several instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) 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: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A method of communication handover, comprising:

a source base station receives a measurement report reported by user equipment;

and the source base station selects candidate base stations for the user equipment according to the measurement report, wherein the candidate base stations are divided into at least two levels, the candidate base stations with different levels have different possibilities of being selected by the user equipment as target base stations for handover, the candidate base stations with different levels have different handover preparation information integrity and/or handover processes, and the higher the possibility of being used as the target base station is, the higher the corresponding handover preparation information integrity is and/or the simpler the handover process is.

2. The method of claim 1,

the candidate base stations are divided into at least a first-stage candidate base station and a second-stage candidate base station, the switching preparation information corresponding to the first-stage candidate base station is complete, and the corresponding switching process does not include the target base station to obtain the supplementary information; and the handover preparation information corresponding to the second-stage candidate base station is incomplete, and the corresponding handover process comprises the step that the target base station allocates resources for the user equipment.

3. The method of claim 2,

the candidate base stations are further divided into third-stage candidate base stations, and the switching process corresponding to the third-stage candidate base stations comprises the steps that the target base station acquires the deficient information from the source base station and allocates resources for the user equipment.

4. The method of claim 3,

the target base station acquiring the missing information from the source base station comprises:

and the source base station sends the deficient information to the target base station.

5. The method of claim 2,

the target base station allocating resources to the user equipment includes:

and the user equipment and the target base station perform RRC connection reestablishment.

6. The method according to any one of claims 1 to 5,

the selecting, by the source base station, a candidate base station for the ue according to the measurement report further includes:

the source base station sends a handover request instruction to the candidate base station, receives a handover preparation confirmation message sent by the candidate base station in response to the handover request instruction, and sends an automatic handover instruction to the user equipment, wherein the handover request instruction includes information of the user equipment, the automatic handover instruction includes information of the candidate base station and a handover condition, and the handover preparation information includes at least one of the information of the user equipment in the handover request instruction, the information of the candidate base station in the automatic handover instruction, and the information of the candidate base station in the handover preparation confirmation message.

7. The method of claim 6,

the handover request instruction and/or the automatic handover instruction further include a level identifier of the candidate base station.

8. The method of claim 6,

the information of at least part of the candidate base stations included in the automatic handover command is from the handover preparation confirm message.

9. The method of claim 6,

after the source base station sends the automatic switching instruction to the user equipment, the method further comprises the following steps:

the source base station confirms the target base station selected by the user equipment;

and the source base station sends a resource release message to other unselected candidate base stations to enable the source base station to release the resources reserved for the user equipment.

10. A method of communication handover, comprising:

the user equipment reports a measurement report to a source base station;

the UE receives an automatic switching instruction from the source base station, the automatic switching instruction comprises information of candidate base stations and switching conditions, the candidate base stations are selected by the source base station for the UE according to the measurement report, the candidate base stations are divided into at least two levels, the candidate base stations in different levels are different in possibility of being selected by the UE as target base stations for switching, the switching preparation information integrity and/or switching processes corresponding to the candidate base stations in different levels are different, and the higher the possibility of being used as the target base station is, the higher the switching preparation information integrity corresponding to the candidate base station is and/or the simpler the switching process is.

11. The method of claim 10,

12. The method of claim 11,

the target base station allocating resources to the user equipment includes:

and after the user equipment is accessed to the target base station, RRC connection reestablishment is carried out between the user equipment and the target base station.

13. The method according to any one of claims 10 to 12,

the automatic handover command further includes a rank identification of the candidate base station.

14. A method of communication handover, comprising:

the candidate base station receives a handover request instruction from a source base station, wherein the handover request instruction comprises information of the user equipment, the candidate base station is selected by the source base station for the user equipment according to a measurement report reported by the user equipment, the candidate base station is divided into at least two levels, the candidate base stations in different levels are selected by the user equipment to be used as target base stations for handover with different possibilities, the handover preparation information integrity and/or handover procedures corresponding to the candidate base stations in different levels are different, and the higher the possibility that the candidate base station is used as the target base station is, the higher the handover preparation information integrity corresponding to the candidate base station is and/or the simpler the handover procedure is.

15. The method of claim 14,

16. The method of claim 15,

17. The method of claim 16,

and the target base station receives the deficient information sent by the source base station.

18. The method of claim 16,

the target base station is divided into a third stage, and the information of the user equipment included in the handover request instruction does not include the complete context and radio bearer information of the user equipment.

19. The method of claim 15,

the target base station allocating resources to the user equipment includes:

and the target base station and the user equipment perform RRC connection reestablishment.

20. The method of claim 15,

the candidate base station is divided into a first stage, and after receiving the handover request command from the source base station, the candidate base station further comprises:

the candidate base station executes admission control and judges whether enough resources are available for receiving the user equipment;

if the resource is enough, the candidate base station responds to the switching request instruction to execute switching preparation to allocate the resource for the user equipment, and sends a switching preparation confirmation message to the source base station, wherein the switching preparation confirmation message is used for indicating that the admission control is successful and comprises at least part of the information of the candidate base station; and if the resources are not enough, the candidate base station sends a switching preparation non-acknowledgement message, wherein the switching preparation non-acknowledgement message is used for indicating that the admission control fails.

21. The method of claim 15,

the candidate base station is divided into a second stage, and the candidate base station further comprises after receiving the handover request command from the source base station:

if the resource is enough, the candidate base station sends a switching preparation confirmation message to the source base station, wherein the switching preparation confirmation message is used for indicating that the admission control is successful; and if the resource is not enough, the candidate base station sends a switching preparation non-acknowledgement message to the source base station, wherein the switching preparation non-acknowledgement message is used for indicating that the admission control fails.

22. The method according to any one of claims 14-21,

after receiving the handover request instruction from the source base station, the candidate base station further comprises:

the candidate base station receives a resource release message from the source base station;

and the candidate base station responds to the resource release message to release the resources reserved for the user equipment.

23. The method according to any one of claims 14-21,

the handover request instruction further includes a rank identification of the candidate base station.

24. A communication switching apparatus comprising a processor and a communication circuit, so that said processor is connected to said communication circuit;

the processor is configured to execute instructions to implement the method of any one of claims 1-23.

25. A communication switching apparatus having stored instructions which, when executed, implement the method of any one of claims 1 to 23.

26. A communication switching apparatus, comprising:

a receiving module, configured to receive a measurement report reported by a user equipment;

a selecting module, configured to select a candidate base station for the ue according to the measurement report, where the candidate base station is divided into at least two levels, the candidate base stations at different levels have different possibilities of being selected by the ue as target base stations for handover, the candidate base stations at different levels have different handover preparation information integrity and/or handover procedures, and the higher the possibility of being used as the target base station is, the higher the handover preparation information integrity and/or the simpler the handover procedure is.

27. A communication switching apparatus, comprising:

a reporting module, configured to report a measurement report to a source base station;

a receiving module, configured to receive an automatic handover instruction from the source base station, where the automatic handover instruction includes information of candidate base stations and handover conditions, and the candidate base stations are selected by the source base station for the ue according to the measurement report, where the candidate base stations are divided into at least two levels, the candidate base stations in different levels have different possibilities of being selected by the ue as target base stations for handover, the candidate base stations in different levels have different integrity of handover preparation information and/or different handover procedures, and the candidate base station has a higher possibility of being used as the target base station, and the candidate base station has a higher integrity of the handover preparation information and/or a simpler handover procedure.

28. A communication switching apparatus, comprising:

a receiving module, configured to receive a handover request instruction from a source base station, where the handover request instruction includes information of the ue, and the candidate base station is selected by the source base station for the ue according to a measurement report reported by the ue, where the candidate base station is divided into at least two levels, the candidate base stations in different levels have different possibilities of being selected by the ue as target base stations for handover, the candidate base stations in different levels have different integrity degrees of handover preparation information and/or different handover procedures, and the higher the possibility of being used as the target base station is, the higher the integrity degree of the handover preparation information corresponding to the candidate base station is and/or the simpler the handover procedure is.