RU2772653C2 - Communication method, source base station, destination base station, core network device and terminal device - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: invention relates to wireless communication. In implementing the handover method, an accepted session ID and a rejected session ID are transmitted in a route switch request so that the core network device can determine the deactivated session from all stored sessions of the terminal. Thus, the core network device does not need to process such sessions, but only needs to process the accepted session and the rejected session, thereby improving processing efficiency.

EFFECT: increasing the rate of successful handover attempts.

28 cl, 19 dwg, 6 tbl

Description

The field of technology to which the invention relates

The present invention relates to the field of communication technologies and, in particular, to a communication method, a source base station, a target base station, a core network device, and a terminal device.

State of the art

5G introduced the concept of a network segment. The terminal is currently running multiple sessions, and the sessions require network segments corresponding to the different sessions to serve the sessions. In this case, if the terminal device needs to access the network and establish multiple sessions, the base station connected to the terminal device must support network segments corresponding to all sessions or some sessions in the terminal device.

Under these circumstances, it is necessary to solve the technical problem of increasing the rate of successful handover attempts.

Disclosure of the essence of the invention

To solve the technical problem, the embodiments of the present invention provide a communication method, a source base station, a target base station, a core network device, and a terminal device for increasing the rate of successful handover attempts.

According to a first aspect, an embodiment of the present invention provides a communication method including:

transmitting, by the source base station, a handover request to a target base station, where the handover request is used to request handover of a terminal device session from the source base station to the target base station, and the handover request includes a session identifier requested for the handover, and information indicating the network segment corresponding to the session; and receiving, by the source base station, a handover response message from the target base station, wherein the handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment from the session that is requested for handoff.

In a first aspect, a source base station can obtain, using a target base station, cause information that corresponds to a session that is rejected by the target base station due to a network segment to help provide information for another session to be requested for handover to the target base station. station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the rate of successful handover attempts.

With reference to the first aspect, in an exemplary implementation, the source base station sends a handover command to the terminal if the handover response message is a handover request acknowledgment message, wherein the handover command includes retransmission indication information corresponding to the session that is rejected. by the target base station and retransmission indication information corresponding to the session is used to indicate whether the terminal device is allowed to route to the network segment supported by the target base station the data flow of the rejected session. Alternatively, the retransmission indication information may not indicate the specific network segment to which the data flow is routed. Thus, the tag can learn which sessions can still be re-established at the target base station after rejection, thereby increasing session handover flexibility.

With reference to the first aspect, in an exemplary implementation, the method further includes: sending, by the source base station, a Radio Resource Control Connection RRC Release message to the terminal if the handover response message is a handover failure message. Alternatively, the RRC connection release message includes indication information of a network segment supported by the neighbor cell of the source cell, information of indication of the network segment supported by the TA/RA to which the neighbor cell of the source cell belongs, or information of the network segment supported by the neighbor base station of the source cell. stations. In this case, the terminal may release the RRC connection as soon as possible to avoid a subsequent communication failure and reduce overhead.

According to a second aspect, an embodiment of the present invention provides a communication method including:

receiving, by the target base station, a handover request from the source base station, wherein the handover request is used to request handover of a terminal device session from the source base station to the target base station, and the handover request includes a session identifier that is requested for the handover , and network segment indication information corresponding to the session; and transmitting, by the target base station, a handover response message to the source base station, where the handover response message includes rejection indication information, and rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to a network segment. , from the session that is being requested for handoff.

In a second aspect, the target base station may notify the source base station of the reason information that corresponds to the session that is rejected due to the network segment of the target base station to facilitate providing information for another session at the source base station, and what needs to be requested for handover to the target base station. base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the rate of successful handover attempts.

With reference to the second aspect, in an exemplary implementation, the target base station receives a handover acknowledgment message from the terminal, and the target base station sends a route switch request to the core network device, where the route switch request includes a session identifier that is received by the target base station, and a session ID that is rejected by the target base station; and the target base station receives a route switch request response message from the core network device, where the route switch request response message includes a session identifier for which the path switch was successfully completed. In this case, the core network device performs a route switch in the received session.

According to a third aspect, an embodiment of the present invention provides a communication method including:

receiving, by the core network device, a route switch request from a target base station, the route switch request including a session ID that is accepted by the target base station and a session ID that is rejected by the target base station; performing, by the core network device, a route switch in the received session and performing a deactivation or release of the rejected session; and transmitting by the core network device a route switch request response message to the target base station, the route switch request response message including a session identifier for which the route switch was successfully completed.

In a third aspect, an accepted session ID and a rejected session ID are transmitted in the route switch request so that the core network device can determine the deactivated session from all of the terminal's stored sessions. Thus, the core network device does not need to process such sessions, but only needs to process the accepted session and the rejected session, thereby improving processing efficiency.

With reference to the first aspect or the second aspect, in an exemplary implementation, the session requested for the handover includes the first session, and the network segment corresponding to the first session is maintained by the target base station. In this case, the target base station does not need to perform access control in the second session, thereby saving processing time for performing access control in the second session. Alternatively, the session requested for handover includes a first session and a second session, a network segment corresponding to the first session is supported by the target base station, and a network segment corresponding to the second session is not supported by the target base station. Therefore, the target base station can directly determine a session that is not supported by the target base station, thereby improving the efficiency of determining the handover response message. Of course, the special classification processing may not be performed on all sessions to be handed off.

With reference to the first aspect, the second aspect, or the third aspect, in a possible implementation, the cause information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

With reference to the first aspect or the second aspect, in an exemplary implementation, if the handover response message is a handover request confirmation message, then the handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station, and information the retransmission indication corresponding to the session is used to indicate whether the terminal device is allowed to route the network segment supported by the target base station to the data flow of the rejected session. Thus, the tag can learn which sessions can still be re-established at the target base station after rejection, thereby improving session handover flexibility.

With reference to the first aspect or the second aspect, in an exemplary implementation, if the handover response message is a handover request acknowledgment message, then the handover request acknowledgment message further includes a rejected bearer identifier or a rejected session data stream identifier of the requested handover. so that the source base station can acknowledge the rejected bearer or the rejected data stream.

With reference to the first aspect or the second aspect, in an exemplary implementation, the handover request response message further includes information about the supported network segment of the target base station. This helps the target base station to notify the source base station of the network segment information currently supported by the target base station, thereby reducing the amount of signaling between the source base station and the target base station.

With reference to the second aspect or the third aspect, in an exemplary implementation, the route switching request further includes information of specifying a network segment corresponding to the session that is rejected by the target base station. In this case, the core network device may compare the network segment corresponding to the rejected session with the network segment supported by the target base station and stored in the core network device to know whether the session was rejected because the target base station does not support the network segment. If yes, then the core network device subsequently initiates a session remove process to reduce the amount of memory occupied by such sessions in the core network device. If not, then the core network device may subsequently initiate a session deactivate process so that the core network device can quickly resume the session when the session needs to be activated.

With reference to a second aspect or a third aspect, in an exemplary implementation, the route switch request further includes cause information corresponding to the session being rejected by the target base station. The reason information is transmitted so that the core network device can perform different processing of sessions rejected for different reasons.

According to a fourth aspect, an embodiment of the present invention provides a communication method including:

receiving, by the terminal, an RRC release message of the radio resource control connection from the source base station; and releasing an RRC connection, where the RRC connection release message includes information on the supported network segment designation of the neighbor cell of the source cell, information on the supported network segment designation of the TA/RA to which the neighbor cell of the source cell belongs, or supported network segment information of the neighbor base station of the source cell. base station.

In a fourth aspect, the terminal may release the RRC connection as soon as possible to avoid subsequent radio link failure and reduce overhead.

According to a fifth aspect, an embodiment of the present invention provides a communication method including:

transmission by the source base station of the first handover request to the core network device, where the first handover request is used to request handover of the terminal device session from the source base station to the target base station, and the first handover request includes information about the target base station and an identifier session requested for handover; and receiving, by the source base station, a first handover response message from the core network device, where the first handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment, from the session requested for handoff.

In a fifth aspect, a source base station can obtain, using a core network device, cause information that corresponds to a session that is rejected by the target base station due to a network segment to help provide information for another session to be requested for handover to the target base station. . When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the rate of successful handover attempts.

With reference to the fifth aspect, in an exemplary implementation, the method further includes: transmitting, by the source base station, a handover command to the terminal device if the first handover response message is a first handover request acknowledgment message, where the handover command includes retry indication information. transmission corresponding to the session that is rejected by the target base station and retransmission indication information corresponding to the session are used to indicate whether the terminal device is allowed to route, to the supported network segment of the target base station, the data stream of the rejected session. Alternatively, the retransmission indication information may not indicate the specific network segment to which the data flow is routed. In this way, the terminal can learn which sessions can still be re-established at the target base station after rejection, thereby improving session handover flexibility.

With reference to the fifth aspect, in an exemplary implementation, the method further includes: sending an RRC connection release message to the terminal device by the source base station if the first handover response message is the first handover failure message. Alternatively, the RRC connection release message includes source base station neighbor cell supported network segment indication information, source base station neighbor cell supported network segment indication information of the TA/RA to which the source base station neighbor cell belongs, or source base station neighbor base station supported network segment information. In this case, the terminal may release the RRC connection as soon as possible to avoid subsequent radio link failure and reduce overhead.

According to a sixth aspect, an embodiment of the present invention provides a communication method including:

reception by the core network device of the first handover request from the source base station, where the first handover request is used to request handover of the terminal device session from the source base station to the target base station, and the first handover request includes information about the target base station and an identifier the session that is requested for handover; and sending, by the core network device, a first handover response message to the source base station, where the first handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information of the corresponding session that is rejected by the target base station due to the network segment from the session that is requested for handoff.

In a sixth aspect, the core network device may notify the source base station of the reason information that corresponds to the session that is rejected by the target base station due to the network segment to facilitate providing information for another session that is in the source base station and should be requested for transmission. service of the target base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the rate of successful handover attempts.

With reference to the sixth aspect, in an exemplary implementation, before the core network device sends the first handover response message to the source base station, the method further includes: sending the core network device a second handover request to the target base station, where the second handover request includes: the session identifier itself and the indication information of the network segment corresponding to the session; and receiving by the core network device a second handover response message from the target base station, where the second handover response message includes failure indication information. Thus, the core network device notifies the source base station of the failure indication information.

According to a seventh aspect, an embodiment of the present invention provides a communication method including:

receiving, by the target base station, a second handover request from the core network device, where the second handover request includes a session identifier and a network segment designation information corresponding to the session; and sending, by the target base station, a second handover response message to the source base station, where the second handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment from the session that is requested for handoff.

In a seventh aspect, the target base station may notify the core network device of the cause information that corresponds to the session that the target base station rejects due to the network segment, so that the core network device notifies the source base station of the information. This helps provide information for another session that resides at the source base station and needs to be requested for handover to the target base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the handover success rate.

With reference to the fifth aspect, the sixth aspect, or the seventh aspect, in a possible implementation, the cause information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

With reference to the fifth aspect or the sixth aspect, in an exemplary implementation, the first handover request further includes the first indication information, and the indication information indicates that the source base station does not determine or knows the supported network segment of the target base station, so that the base station device network receives information that the source base station does not know information about the supported network segment of the target base station. Therefore, information about the supported network segment of the target base station can be added to the first handover response message. This reduces the interaction between the source base station and the target base station, and improves the efficiency of obtaining network segment information.

With reference to the fifth aspect or the sixth aspect, in an exemplary implementation, the target base station may be a base station that has a communication interface with the source base station, or may be a base station that does not have a communication interface with the source base station. Alternatively, the first handover request may include second indication information indicating that there is no communication interface between the source base station and the target base station. This helps the core network device to communicate supported network segment information to the target base station.

With reference to the fifth aspect or the sixth aspect, in an exemplary implementation, if the first handover response message is the first handover request acknowledgment message, then the first handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station , and retransmission indication information corresponding to the session is used to indicate whether the terminal device is allowed to route the rejected session data stream to the supported network segment of the target base station. In this way, the terminal can learn which sessions can still be re-established at the target base station after rejection, thereby improving session handover flexibility.

With reference to a fifth aspect or a sixth aspect, in an exemplary implementation, if the first handover response message is a first handover request acknowledgment message, then the first handover request acknowledgment message further includes a rejected bearer identifier or a rejected session data stream identifier requested for handover so that the source base station can acknowledge the rejected bearer or the rejected data stream.

With reference to a fifth aspect or a sixth aspect, in an exemplary implementation, if the first handover response message is a first handover request acknowledgment message, the first handover request acknowledgment message further includes supported network segment information of the target base station. For example, if the first handover request includes first indication information indicating that the source base station does not determine the supported network segment of the target base station, or the core network device determines, based on the second indication information transmitted in the first handover request, that indicates that there is no communication interface between the source base station and the target base station, that the source base station does not know the supported network segment of the target base station, information about the supported network segment of the target base station can be transmitted. This reduces the interaction between the source base station and the target base station, and improves the efficiency of obtaining network segment information.

With reference to the fifth aspect or the sixth aspect, in an exemplary implementation, the first handover request further includes network segment indication information corresponding to the session requested for handover, so that the core network device can directly determine the network segment indication information corresponding to the session, which is requested for handover. It is understood that the first handover request may not include the network segment designation information corresponding to the session requested for the handover. This is not limited in this embodiment of the present invention.

With reference to the fifth aspect or the sixth aspect, in an exemplary implementation, the first handover request further includes a session flow identifier that is requested for handover and to be established, and QoS information corresponding to the data flow. This can save search time, reduce handover delay, and improve handover efficiency.

With reference to the fifth aspect or the sixth aspect, in a possible implementation, the first handover request further includes AMBR information of the maximum aggregated bit rate corresponding to the session. The information is included in the first handover request, so that search time is saved, handover delay is reduced, and handover efficiency is improved.

With reference to the sixth aspect or the seventh aspect, in a possible implementation, the session indicated in the second handover request is the first session, and the network segment corresponding to the first session is supported by the target base station. In this case, the target base station does not need to perform access control in the second session, thereby saving processing time for performing access control in the second session. Alternatively, the session indicated in the second handover request is the first session and the second session, the network segment corresponding to the first session is supported by the target base station, and the network segment corresponding to the second session is not supported by the target base station. Therefore, the target base station can directly determine a session that is not supported by the target base station, thereby improving the efficiency of determining the handover response message. Of course, special classification processing may not be performed on all sessions required for handover.

With reference to the sixth aspect or the seventh aspect, in an exemplary implementation, if the second handover response message is the second handover request acknowledgment message, the second handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station, and retransmission indication information corresponding to the session is used to indicate whether the terminal device is allowed to route the rejected session data stream to the supported network segment of the target base station. Thus, using the source base station, the core network device can learn which sessions can still be re-established in the target base station after rejection, thereby improving session handover flexibility.

With reference to the sixth aspect or the seventh aspect, in an exemplary implementation, if the second handover response message is a second handover request acknowledgment message, the second second handover request acknowledgment message further includes a rejected bearer identifier or a rejected session data stream identifier indicated in the second handover request so that the source base station can acknowledge the rejected bearer or the rejected data stream.

According to an eighth aspect, an embodiment of the present invention provides a communication method, including: transmitting, by a first base station, a first message to a core network device, the first message being used to obtain supported network segment information for a PLMN of the core network device; and receiving, by the first base station, a second message from the core network device, the second message including supported network segment information for the PLMN served by the core network device.

In an eighth aspect, the first base station can obtain, using the core network device, the supported network segment indication information for the PLMN of the core network device and feedback, at the PLMN granularity, of the supported network segment of the core network device. This can improve the accuracy of the first base station's selection of the core network device for the terminal session.

According to a ninth aspect, an embodiment of the present invention provides a communication method, including: receiving a first message from a first base station by a core network device, where the first message is used to obtain information about a supported network segment of the core network device for the PLMN; and sending the core network device a second message to the first base station, where the second message includes supported network segment information for the PLMN served by the core network device.

In a ninth aspect, the core network device can send, to the first base station, the supported network segment indication information for the PLMN served by the core network device, and feed back the supported network segment of the core network device (under PLMN granularity). This can improve the accuracy of the first base station's selection of the core network device for the terminal session.

According to a tenth aspect, an embodiment of the present invention provides a base station, the base station is a source base station, and the source base station includes: a transmission unit configured to transmit a handover request to a target base station, the handover request being used for the handover request a terminal session from a source base station to a target base station, and the handover request includes a session identifier requested for handover and a network segment indication information corresponding to the session; and a receiving unit configured to receive a handover response message from the target base station, wherein the handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment, from the session that is being requested for handoff.

Alternatively, the source base station may further implement some or all of the possible implementations of the first aspect.

According to an eleventh aspect, an embodiment of the present invention provides a base station, the base station is a target base station, and the target base station includes: a receiving unit configured to receive a handover request from a source base station, where the handover request is used to requesting a handover of a session of a terminal device from a source base station to a target base station, and the handover request includes a session identifier requested for handover and information indicating a network segment corresponding to the session; and a transmission unit configured to send a handover response message to the source base station, where the handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment, from the session that is being requested for handoff.

Alternatively, the source base station may further implement some or all of the possible implementations of the second aspect.

According to a twelfth aspect, an embodiment of the present invention provides a core network device, and the core network device includes: a receiving unit 1001, configured to receive a route switch request from a target base station, where the route switch request includes a session ID that is received by the target base station. by the station, and the session ID that is rejected by the target base station; a processing unit 1002, configured to perform a route switch in the received session and perform deactivation or release of the rejected session; and a transmission unit 1003, configured to transmit a route switch request response message to a target base station, where the route switch request response message includes a session identifier for which the route switch was successfully completed.

Alternatively, the source base station may further implement some or all of the possible implementations of the third aspect.

According to a thirteenth aspect, an embodiment of the present invention provides a tag, and the tag includes: a receiving unit, configured to receive an RRC release message of a radio resource control connection from a source base station; and a processing unit configured to release the RRC connection, where the RRC connection release message includes information on the supported network segment indication of the neighbor cell of the source cell, information on the indication of the supported network segment of the TA/RA to which the neighbor cell of the source cell belongs, or information on the supported network segment. segment of the neighbor base station of the source base station.

Alternatively, the terminal may further implement the communication method in the fourth aspect.

According to a fourteenth aspect, an embodiment of the present invention provides a base station, the base station is a source base station, and the source base station includes: a transmission unit configured to send a first handover request to a core network device, where the first handover request is used to request handover of a session of a terminal device from a source base station to a target base station, and the first handover request includes information about the target base station and a session ID requested for the handover; and a receiving unit configured to receive a first handover response message from the core network device, where the first handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station from -for the network segment from the session that is requested for handover.

Alternatively, the source base station may further implement some or all of the possible implementations of the fifth aspect.

According to a fifteenth aspect, an embodiment of the present invention provides a core network device, and the core network device includes: a receiving unit configured to receive a first handover request from a source base station, where the first handover request is used to request handover of a session of a terminal device from the source base station to the target base station, and the first handover request includes information about the target base station and a session identifier requested for the handover; and a transmission unit configured to send the first handover response message to the source base station, where the first handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station from -for the network segment from the session that is requested for handoff.

Alternatively, the core network device may further implement some or all of the possible implementations of the sixth aspect.

According to a sixteenth aspect, an embodiment of the present invention provides a base station, the base station is a target base station, and the target base station includes: a receiving unit configured to receive a second handover request from a core network device, the second handover request including session ID and information specifying the network segment corresponding to the session; and a transmission unit configured to transmit the handover response message to the source base station, wherein the handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to per network segment, from the session that is being requested for handoff.

Alternatively, the target base station may further implement some or all of the possible implementations of the seventh aspect.

According to a seventeenth aspect, an embodiment of the present invention provides a base station, and the base station is the first base station, including: a transmission unit 1101 configured to send a first message to a core network device, where the first message is used to obtain information about a supported network segment of the device core network for PLMN; and a receiving unit 1102, configured to receive a second message from the core network device, where the second message includes supported network segment information for the PLMN served by the core network device.

Alternatively, the source base station may further implement some or all of the possible implementations of the seventh aspect.

According to an eighteenth aspect, an embodiment of the present invention provides a core network device, and the core network device includes: a receiving unit configured to receive a first message from a first base station, where the first message is used to obtain information about a supported network segment of the core network device for PLMNs; and a transmission unit configured to send a second message to the first base station, where the second message includes supported network segment information for the PLMN served by the core network device.

Alternatively, the source base station may further implement some or all of the possible implementations of the ninth aspect.

According to a nineteenth aspect, a communication device is provided. The communication device may be a base station in the above method, or may be a chip located in the base station. The communication device includes a memory, a transceiver and a processor. The memory is configured to store computer-executable program code, and the processor is connected to the memory and a transceiver. The program code stored in the memory includes an instruction, and when the processor executes the instruction, the communication device is allowed to execute the method performed by the terminal in any possible implementation of the first aspect, the second aspect, the fifth aspect, the seventh aspect, or the eighth aspect.

According to a twentieth aspect, a communication device is provided. The communication device may be a core network device in the above method, or may be a chip located in the core network device. The communication device includes a memory, a transceiver and a processor. The memory is configured to store computer-executable program code, and the processor is connected to the memory and a transceiver. The program code stored in the memory includes an instruction, and when the processor executes the instruction, the communication device is allowed to execute the method performed by the network device in any possible implementation of the third aspect, the sixth aspect, or the ninth aspect.

According to the twenty-first aspect, a communication device is provided. The communication device may be a terminal device in the above implementation of the method, or may be a chip located in the terminal device. The communication device includes a memory, a transceiver and a processor. The memory is configured to store computer-executable program code, and the processor is connected to the memory and a transceiver. The program code stored in the memory includes an instruction, and when the processor executes the instruction, the communication device is allowed to execute the method performed by the terminal device in any possible implementation of the fourth aspect.

According to a twenty-second aspect, a computer program product is provided, and the computer program product includes computer program code. When the computer program code is executed on the computer, the computer is permitted to execute the method in any of the first aspect to the ninth aspect and possible implementations of the first aspect to the ninth aspect.

According to the twenty-third aspect, a computer-readable medium is provided, and the computer-readable medium stores program code. When the computer program code is executed on the computer, the computer is permitted to execute the method in any of the first aspect to the ninth aspect and possible implementations of the first aspect to the ninth aspect.

According to a twenty-fourth aspect, a chip including a processor and a memory is provided. The memory is configured to store a computer program, and the processor is configured to recall the computer program from the memory and run the computer program. The computer program is used to implement the method in any of the first aspect through the ninth aspect and possible implementations of the first aspect through the ninth aspect.

Brief description of the drawings

For the purpose of explaining in more detail the technical solutions in the embodiments of the present invention or in the section "prior art", the following briefly describes the accompanying drawings necessary to describe the embodiments of the present invention or the prior art.

Fig. 1 is an example architecture diagram of a communication system according to an embodiment of the present invention;

fig. 2 is a possible diagram of a core network device according to an embodiment of the present invention;

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

fig. 4 is a flowchart of another communication method according to an embodiment of the present invention;

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

fig. 6 is a flowchart of another communication method according to an embodiment of the present invention;

fig. 7 is a flowchart of another communication method according to an embodiment of the present invention;

fig. 8 is a block diagram of a base station according to an embodiment of the present invention;

fig. 9 is a block diagram of a base station according to an embodiment of the present invention;

fig. 10 is a block diagram of a core network device according to an embodiment of the present invention;

fig. 11 is a block diagram of another base station according to an embodiment of the present invention;

fig. 12 is a block diagram of another core network device according to an embodiment of the present invention;

fig. 13 is a block diagram of another base station according to an embodiment of the present invention;

fig. 14 is a block diagram of another base station according to an embodiment of the present invention;

fig. 15 is a block diagram of another core network device according to an embodiment of the present invention;

fig. 16 is a block diagram of a terminal device according to an embodiment of the present invention;

fig. 17 is a block diagram of another base station according to an embodiment of the present invention;

fig. 18 is a block diagram of another core network device according to an embodiment of the present invention; and

fig. 19 is a block diagram of another terminal according to an embodiment of the present invention.

Implementation of the invention

The following describes the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention.

Network elements in embodiments of the present invention are described as follows:

The terminal device may be a user equipment (UE) and the UE implements the access network side using the network access device. For example, the terminal device may be a portable terminal device, laptop, subscriber unit (subscriber unit), cellular phone (cellular phone), smart phone (smart phone), wireless data card, personal digital assistant (personal digital assistant, PDA), pocket computer , tablet computer, wireless modem (modem), portable (handheld) device, laptop computer (laptop computer), cordless phone (cordless phone) or wireless local loop station (wireless local loop, WLL), machine type communication terminal (machine type communication , MTS) or other device that can access the network. The terminal device and the network access device communicate with each other using air interface technology.

The radio access network (RAN) is mainly configured to manage radio resources, quality of service (QoS), data compression and encryption, and other functions on the radio interface side. The network access device may include various forms of base stations, such as a macro base station, a micro base station (also referred to as a small cell), a relay node, and an access point. In systems that use different radio access technologies, a device with a base station function may have different names. For example, a device is referred to as a gNB in a 5th generation (5G) system, refers to an evolved NodeB (evolved nodeB, eNB, or eNodeB) in an LTE system, or is referred to as a NodeB (nodeB) in a 3rd generation system ( 3rd generation, 3G).

The core network device is configured to provide a user connection and perform user management and service transmissions. For example, establishing a user connection includes features such as mobility management (MM) and paging (paging). User management includes user description, QoS, and security (relevant security measures provided by the authentication center include mobile service security management and external network access security processing). The link connection includes a public switched telephone network (PSTN), a public switched telephone network (PSTN), an external network data network, a packet data network, the Internet, and the like.

For example, the core network device may include an access and mobility management function (AMF) network element and is primarily responsible for signal processing, i.e., control plane functions including access control, mobility management , attachment and detachment, and other functions.

Alternatively, the core network device may further include a session management function (SMF) network element and is responsible for session management functions such as session setup, session change, and session release.

Alternatively, the core network device may further include a user plane function (UPF) network element and is responsible for forwarding and receiving user data at the terminal device. The UPF network element may receive user data from the data network and transmit the user data to the terminal device using the network access device. The UPF network element may further receive user data from the terminal using the network access device and forward the user data to the data network. The transfer and resource scheduling function for servicing a terminal device in the UPF network element is managed and controlled by the SMF network element. The core network device in the embodiments of the present invention is not limited to the AMF network element, SMF network element, and UPF network element.

Referring to FIG. 1, fig. 1 is an exemplary diagram of a communication system architecture used in an embodiment of the present invention. As shown in FIG. 1 shows that the network access device can be connected to at least one terminal device. For example, network access device 101 is connected to both terminal device 104 and terminal device 105, and network access device 102 is connected to both terminal device 106 and terminal device 106. The network access device may be connected to at least one core network device 103. For example, both the network access device 101 and the network access device 102 are connected to the core network device 103.

Between the core network device and the access network device, I use the control plane interface. For example, an interface is used between a core network device and an access network, and is referred to as an N2 interface or NG interface in the present specification.

For example, if there is a communication interface such as the Xn interface between the network access device 101 and the network access device 102 in FIG. 1, the network access device 101 and the network access device 102 can communicate with each other; in the absence of a communication interface between the network access device 101 and the network access device 102 in FIG. 1, the network access device 101 and the network access device 102 cannot communicate with each other. Therefore, the network access device 101 and the network access device 102 can respectively transmit, only if there is a communication interface, information about the network segments supported by the network access device 101 and the network access device 102. In the absence of an interface, the network access device 101 and the network access device 102 cannot communicate with each other, and furthermore, cannot send information about the network segments supported by the network access device 101 and the network access device 102, respectively.

Core network device 103 may include at least one AMF network element and alternatively may further include an SMF network element and a UPF network element. The network access device 102 may be connected to one or more AMF network elements. One AMF network element may support one or more network segments of different types, and the types of network segments supported by different AMF network elements may be different. Each SMF may support one or more network segments of different types, and the types of network segments supported by different SMFs may differ. One AMF network element may establish a communication connection with multiple SMF network elements. Alternatively, one SMF NE may be connected to multiple AMF NEs. In addition, one SMF network element can be connected to multiple UPF network elements, and one UPF network element can be connected to one SMF network element. In this case, one SMF network element can manage and control multiple UPF network elements, and one UPF network element is managed and controlled by one SMF. The UPF network element may establish a connection with the network access device to carry out data transmission of the terminal device.

For example, referring to FIG. 2, fig. 2 is a possible diagram of a core network device according to an embodiment of the present invention. One AMF network element 201 establishes a connection with two SMF network elements: SMF network element 202 and SMF network element 203. Network segment types supported by AMF network element 201 include network segment type 1 and network segment type 2. Network segment type 1 is network segment type 1, and network segment type 2 is network segment type 2. SMF network element 202 is an SMF network element corresponding to network segment 1, and SMF network element 203 is an SMF network element corresponding to network segment 2 A single SMF NE can manage and control multiple UPF NEs. For example, SMF network element 202 manages UPF network element 204, UPF network element 205, and UPF network element 206, and SMF network element 203 manages UPF network element 204 and UPF network element 208.

Because the end device provides many types of services such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLC), and mass machine type communications (mMTC) ), the network segments corresponding to different types of service sessions may be different. Due to different provided operators or service providers, the same type of service may correspond to different network segments. Different network access devices may support different network segments. In this case, if the terminal device needs to access the network and establish multiple sessions, the network access device connected to the terminal device must support network segments corresponding to all sessions or some sessions in the terminal device.

Handoff to the network access device must be performed for the tag due to movement of the tag's location, load balance, and the like. For example, with reference to FIG. 1, a session handover of a terminal device 104 must be performed from a network access device 101 to another network access device 102. However, the successful completion of the handover is closely related to whether the network access device 102 supports the network segment corresponding to the session of the network access device 104 . In fact, the network access device 101 sends a handover request to the network access device 102, but the handover of some sessions usually cannot be performed to the network access device 102. There are many reasons why a session handover cannot be performed to the network access device 102 . For example, the radio resource at the network access device 102 is unavailable (radio resource unavailable), or the requested network segment is not supported. However, in the existing solution, the network access device 101 cannot determine the reason why the session handover cannot be performed to the network access device 102. If the resource for the first network segment corresponding to the requested session is not available at the network access device 102, the network access device 101 still sends a handover request to the network access device 102 when a different session handoff is to be performed on the first network segment, and in case when session handoff cannot be performed to the network access device 102 . This reduces the rate of successful handover attempts.

In this embodiment of the present invention, after the network access device 101 sends a handover request to the network access device 102, the network access device 101 can obtain session reason information that is rejected due to the network segment of the network access device 102 to help provide information for another session to be requested for handover to the network access device 102 . When performing handover of a session corresponding to the same network segment from the network access device 101, the access network device 101 can directly determine whether the session can be handed over to the network access device 102, thereby increasing the rate of successful handover attempts. The network access device 101 may further select a better target base station for another terminal to perform a handover for the handover.

It should be noted that an example in which the network access device is a base station is used for description in the embodiments of this application. In any embodiment of the present invention, the supported network segment information of the base station may alternatively include at least one cell ID of the base station and indication information of at least one network segment corresponding to each cell ID. One base station may cover one or more cells. Each cell is specified using a cell ID, and each cell may support one or more network segments. Each cell supports a different network segment, and such a cell ID may correspond to the designation information of at least one network segment. For example, a specific representation form is shown below (the title is merely an example, and the title is not limited in the embodiments of the present invention). The cell ID represents a cell ID, the S-NSSAI list represents network segment designation information, and one cell ID may correspond to at least one S-NSSAI list.

>>> cell ID

>>> S-NSSAI list

Alternatively, in another possible order, the supported network segment information of the base station may include information about the base station and indication information of at least one network segment corresponding to the base station. Each base station may support one or more network segments, and therefore, information about one base station may correspond to indication information of at least one network segment. For example, a specific representation form is shown below (the title is merely an example, and the title is not limited in the embodiments of the present invention). The gNB ID represents base station information, the S-NSSAI list represents network segment designation information, and one gNB ID may correspond to at least one S-NSSAI list.

>>> gNB ID

>>> S-NSSAI list

Alternatively, in another possible order, the supported network segment information of the base station may include information indicating at least one network segment corresponding to the tracking area (TA) or registration area (RA) to which the cell of the base station belongs. stations. Each TA/RA may support one or more network segments, and therefore, information about one TA/RA may correspond to indication information of at least one network segment. For example, a specific representation form is shown below (the title is merely an example, and the title is not limited in the embodiments of the present invention). A tracking area identity/identifier (TAI), a registration area identity/identifier (RAI), a tracking area Code (TAC), or a registration area Code (RAC) is used to represent TA/RA information, the S-NSSAI list represents network segment designation information, and one TAI/RAI/TAC/RAC may correspond to at least one S-NSSAI list.

>>>TAI/RAI/TAC/RAC

>>> S-NSSAI list

The base station information in any embodiment of the present invention may include at least one of a base station identifier, a base station central unit ID, a base station distributed unit ID, a Physical Cell Identifier (Physical Cell Identifier, PCI) of the base station and the global cell identifier (Cell Global ID, CGI) of the base station.

It should be further noted that the indication information of each network segment in any embodiment of the present invention may include at least one of a network segment identifier, single network slice selection assistance information (S-NSSAI), and information assistance in choosing a RAN network segment (RAN network slice selection assistance information, R-NSSAI).

The network segment ID may be represented using at least one of the following items (1) - (7):

(1) Network segment type information. For example, the network segment type information may indicate a network segment type such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLC), and streaming machine-type communications (massive machine type communications, mMTC), Alternatively, the network segment type information may indicate the type of end-to-end network segment, including the network segment type of the RAN core network (Core Network, CN), or may indicate the network segment type on the RAN side or the type network segment on the CN side.

(2) Service type information related to a particular service. For example, the service type information may indicate a service function such as a video service, Internet of Vehicles service, or voice service, or information about a specific service.

(3) Tenant information used to instruct the formation or tenancy of network segment client information such as Tencent or State Grid.

(4) User group information used to instruct user grouping based on a function such as a user level.

(5) Segment group information used to instruct network shards to be grouped based on an attribute. For example, the feature includes that all network segments that a terminal can access can be used as a segment group. Or, the hop group may be defined according to another criterion.

(6) Network segment instance information used to indicate the ID and the instance tag information generated for the network segment. For example, an identifier indicating the network segment instance may be assigned to the network segment instance, or a new identifier may be mapped based on the network segment instance identifier and associated with the network segment instance. The receiving party may identify, based on the identifier, the specific instance of the network segment indicated by the identifier.

(7) Dedicated Core Network (DCN) ID. The identifier is used to uniquely identify a dedicated core network in a Long Term Evolution (LTE) or enhanced LTE (eLTE) system, such as a dedicated core network in the Internet of Things. Alternatively, the mapping may be performed for the DCN ID and the SNID, the DCN ID may be mapped to the SNID, and the SNID may also be mapped to the DCN ID.

The S-NSSAI includes at least Slice/Service type (SST) information and, alternatively, may further include Slice Differentiator (SD) information. The SST information is used to indicate the behavior of the network segment, such as the attribute and service type of the network segment. The SD information is additional SST information. If SST specifies an implementation of multiple hops, SD may correspond to a unique hop instance.

The R-NSSAI represents the set of specific S-NSSAIs, that is, the set identifier of the specific S-NSSAIs.

It should be understood that in the embodiments of the present invention, the network segment designation information may be represented using at least one of the above parameters. For example, the network segment designation information may be represented using the network segment type, or may be represented using the network segment type and service type, or may be represented using the service type and tenant information. This is not limited in the embodiments of the present invention. The following is a detailed description of the representation of the network segment designation information. Alternatively, the specific encoding format of the network segment indication information is not limited. The information in various fields that can be sent in an interface message between different devices represents different network segment indication information, or can be replaced by abstract index values, and different index values correspond to different network segments. Of course, other identifiers may be used in addition to the above identifiers, and this is not limited here. It should be understood that if a terminal device, network access device, or core network device supports a plurality of network segments, the supported network segment designation information of the terminal device, network access device, or core network device can be represented as a list of the above at least one identifier.

It should be noted that "use the communication interface" or "use the interface" in the embodiments of the present invention indicates that the communication interface is installed and that the communication interface is available (accessible); and that "no communication interface" or "missing interface" indicates that the communication interface is not installed or the installed communication interface is not available (unavailable). The communication interface in this document is not limited to a communication interface between network access devices and a communication interface between a network access device and a core network device.

Embodiments of the present invention may be applied to another communication system that supports a network segment. The terms "system" and "network" can be used interchangeably. The system architecture described in the embodiments of the present invention is intended to more clearly describe the technical solutions in the embodiments of the present invention and does not constitute any limitation on the technical solutions provided in the embodiments of the present invention. One skilled in the art may be aware that as the system architecture evolves, the technical solutions provided in the embodiments of the present invention are also applicable to similar technical problems.

Referring to FIG. 3, fig. 3 shows a communication method according to an embodiment of the present invention. In this embodiment, an example in which the network access device is a base station is used to describe. As shown in FIG. 3, the communication method refers to a terminal device, a source base station, a target base station, and a core network device. Fig. 3 corresponds to the communication method used in the case where the target base station determines that the handover is successful. The source base station is the base station that is currently establishing a communication connection with the terminal device, and the target base station is the base station to which the terminal device session handoff is requested.

As shown in FIG. 3, the communication method includes steps 301 to 307. The following is a detailed description.

301. The source base station sends a handover request to the target base station.

There is a communication interface, such as the Xn interface, between the source base station and the target base station. In this case, the source base station and the target base station can communicate with each other. The handover request is used to request handover of a terminal device session from a source base station to a target base station. The handover request includes a session identifier requested for the handover and information indicating a network segment corresponding to the session. For example, if there are a plurality of sessions requested for handover, the handover request contains information of specifying a network segment corresponding to each session. Accordingly, the target base station receives the handover request.

Alternatively, the session requested for the handover may be an activated session of the tag, and may be understood as a session currently running on the tag. For example, a terminal session includes an A1 session, an A2 session, an A3 session, an A4 session, and an A5 session. Session A1, session A2 and session A3 are in the active state, and session A4 and session A5 are in the deactivated state. In this case, the handover request includes A1 session ID, A2 session ID, A3 session ID, A1 session network segment designation information, A2 session network segment designation information, and A3 session network segment designation information. A deactivated session does not need to be transmitted to the target base station and hence the signaling can be reduced.

Alternatively, before sending the handover request, the source base station may further determine, based on the received supported network segment information of the target base station and the received network segment indication information corresponding to the session requested for handover, the specific session that is in the session requested for handover and whose corresponding network segment is supported by the target base station, and the particular session that is in the session that is requested for handover and whose network segment is not supported by the target base station. In addition, if the target base stations do not support network segments corresponding to all sessions requested for handover, the source base station may not send a handover request to the target base station.

Alternatively, the session requested for the handoff may be the first session and the second session of the terminal. The network segment corresponding to the first session is supported by the target base station, and the network segment corresponding to the second session is not supported by the target base station. Since there is a communication interface between the source base station and the target base station, the source base station can determine, by communicating with the target base station, another base station, a core network side, or the like, a supported network segment of the target base station. In addition, the source base station can classify, based on the indication information of the network segment corresponding to each session requested for handover and the supported network segment of the target base station, the sessions requested for handover to obtain the first session and the second session. For example, the sessions requested for handover include a B1 session, a B2 session, and a B3 session, the target base station supports the network segments corresponding to the B1 session and the B2 session, but the target base station does not support the network segment corresponding to the B3 session. In this case, session IDs requested for handover are classified into two types and sent to the target base station. One type is the id of the first session and the other type is the id of the second session. Therefore, the target base station can directly determine a session that is not supported by the target base station, thereby improving the efficiency of determining the handover response message. Of course, the special classification processing may not be performed on all sessions to be handed off.

Alternatively, the session requested for the handoff may be the first session of the terminal, and the network segment corresponding to the first session is maintained by the target base station. Therefore, for sessions corresponding to network segments that are not supported by the target base station, the target base station does not need to determine whether the network segment corresponding to the session requested for handover is supported, and can directly determine based on the network segment resource usage state of the target base station. station whether to perform handover of the first session. In this case, the target base station does not need to perform access control in the second session, thereby saving processing time for performing access control in the second session.

Alternatively, the source base station selects one of the plurality of base stations that have a communication interface with the source base station as the target base station. In addition, the specific target base station supports network segments corresponding to all or some of the sessions requested for handover, so that a handover failure caused by the target base station not supporting network segments of all sessions requested for handover is avoided. The number of handover failures is reduced, which increases the rate of successful handover attempts.

Alternatively, if the source base station receives the measurement report sent by the terminal, the source base station may select the target base station based on the measurement report and execute step 301 to send a handover request to the target base station. The measurement report includes a measurement report value of at least one of the cell and the base station. Alternatively, if the measurement report includes a cell measurement report value, the cell may be the cell of the source base station or the cell of another base station. If the measurement report includes a base station measurement report value, then the base station may be the source base station or another base station. Alternatively, the number of cells and the number of base stations contained in the measurement report are not limited in this embodiment of the present invention.

302. The target base station performs access control based on a factor such as a network segment support state, a resource usage state, or a handover request. The target base station performs admission control if the target base station receives a handover request sent by the source base station. Alternatively, the target base station determines the handover response message based on such a factor as the network segment designation information corresponding to each session in the handover request, the support state of the target base station, or the resource usage state.

For example, for the B4 session, if the supported network segment information of the target base station includes the network segment designation information corresponding to the B4 session, it indicates that the target base station supports the network segment corresponding to the B4 session. If the supported network segment information of the target base station does not include the network segment indication information corresponding to the B4 session, it indicates that the target base station does not support the network segment corresponding to the B4 session. In this case, session B4 is a rejected session. In addition, when the target base station supports the network segment corresponding to the B4 session, if the target base station can further allocate a resource for the corresponding network segment for the B4 session, the target base station determines that the B4 session is the received session. If the target base station cannot allocate a resource for the corresponding network segment to session B4, the target base station determines that session B4 is a rejected session. Thus, the target base station can determine the handover response message through the access control.

Alternatively, even if only the first session is transferred in step 301, the target base station may check the indication information of the network segment corresponding to the first session (one or more sessions) to determine whether to support the corresponding network segment to the first session at present.

In addition, the handover response message may be a handover request confirmation message, or the handover response message is a handover failure message. In the embodiment shown in FIG. 3, a case is described in which the handover response message is a handover request acknowledgment message. In this case, the session requested for handover includes a session to be handed over to the target base station and a session that is rejected by the target base station. The session may be rejected by the target base station because the target base station does not support the network segment corresponding to the rejected session, or because the resource for the network segment corresponding to the rejected session is not available to the target base station. Therefore, the handover request confirmation message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to the network segment from the session requested for handover. The reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, the reason information in this embodiment of the present invention may be indicated using an information element (information element, IE), a flag (flag), a cause value (cause), or the like, and it is not limited to this embodiment of the present invention.

For example, if the session requested for handover includes a first session and a second session, the rejected session reason information may be: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station, and corresponding to the rejected session. If the session requested for the handover includes the first session, the reason information for the rejected session of the base station is: the resource is not available for the network segment where the network segment corresponds to the rejected session. If the first session includes a plurality of data streams, and at least one data stream of the first session is received (allowed) by the target base station, and at least one data stream is rejected by the target base station, the indication information indicates a reason for rejecting at least one data stream the first session can be transferred. For example, the reason includes: the resource is not available or the resource for the network segment corresponding to the first session is not available at the target base station. The data flow is a traffic flow or a QoS flow (QoS flow).

303. The target base station sends a handover request confirmation message to the source base station.

The handover request confirmation message includes an accepted session ID, a rejected session ID, and reason information corresponding to the rejected session. For example, the handover request acknowledgment message may be a handover acknowledgment or a handover request acknowledgment.

For example, referring to table 1, where table 1 is a session PDU release list or a session PDU reject list. The rejected session ID and the reason information corresponding to the rejected session contained in the handover request acknowledgment message may be presented in Table 1.

Table 1

PDU Session Release List/PDU Session Reject List
(PDU session release list/PDU session denied list) > PDU session ID (PDU Session ID) >> Cause value

Alternatively, the handover request confirmation message further includes retransmission indication information corresponding to the rejected session. The retransmission indication information is used to indicate whether the terminal device is allowed to route the rejected session data flow to the supported network segment of the target base station. For example, the rejected session is session B1 and session B1 corresponds to network segment 1. The rejected session B1 reason information can be: the target base station does not support network segment 1 corresponding to session B1, or the target base station supports network segment 1, but the resource for the network segment 1 is not available. Regardless of the reason for rejecting session B1, if the target base station supports network segment 2 and the traffic of session B1 is routed to network segment 2, data transmission can also be realized. In this case, the target base station determines that the retransmission indication information corresponding to session B1 is: the terminal device is allowed to route the data flow of session B1 to network segment 2 supported by the target base station. It is understood that the retransmission indication information may not indicate the specific network segment to which the data flow is routed. In addition, if the network segment to which the B1 session traffic can be routed is not present in the target base station or the target base station cannot satisfy the QoS requirement of the B1 session traffic, the target base station determines that the retransmission indication information corresponding to the B1 session , is as follows: the end device is not allowed to route the B1 session traffic to the supported network segment of the target base station. It is understood that the retransmission indication information and the reason information can be identified using the IE/flag/reason value. The IE/flag/reason value indicates the reason for rejecting the session and also indicates that the data stream corresponding to the rejected session may be directed to another network segment. To be specific, the session may be re-established on another supported network segment of the target base station to transmit the data stream. The retransmission indication information and the reason information can be identified using two different IE/flags/reason values.

Alternatively, the handover request acknowledgment message further includes a rejected bearer identifier or a rejected session data stream identifier of the session requested for the handover. One session includes multiple data streams. One bearer may correspond to multiple data streams. The rejected bearer may be a channel in a received session, or may be a channel in a rejected session. The rejected data stream may be a received session data stream or may be a rejected session data stream. For example, at least one received session bearer is a rejected bearer and at least one received session data stream is a rejected data stream. The rejected bearer or the rejected data stream is sent to the source base station using a handover request acknowledgment message so that the source base station can acknowledge the rejected bearer or the rejected data stream.

For example, if the handover request acknowledgment message further includes a rejected data stream identifier referring to Table 2, table 2 includes an accepted session identifier, rejected data stream reason information, and a rejected data stream identifier. The list of received sessions may be in the form of an Allowed Session PDU List (Allowed Session PDU List) or a Session PDU Handoff List (List of Session PDUs to be Forwarded).

table 2

List of received sessions > PDU session ID (PDU Session ID) > Cause value > identifier/list of rejected data flow identifiers (traffic/QoS flow ID (list))

For example, the above information contained in the handover request confirmation message may be returned as a list. The session requested by the source base station for handover includes the first session and the second session, and the handover response message is defined as a handover request acknowledgment message. For description, an example is used in which the first session includes session C1, session C2 and session C3, and the second session includes session D1 and session D2. The session that is received by the target base station includes a C1 session and a C2 session, and the session that is rejected by the target base station includes a C3 session, a D1 session, and a D2 session. The target base station maintains the network segment corresponding to session C3, but the handover fails because the resource for the network segment is not available. At least one bearer or data stream of the received session C1 is rejected.

In this case, referring to Table 3, Table 3 is a form of a list of accepted sessions according to an embodiment of the present invention. Cause information corresponding to session C1 includes a rejected channel/data stream may be contained in a handover request acknowledgment message. The reason information is used to indicate the reason information of at least one rejected bearer or at least one rejected data stream. For example, the cause information R3 of at least one rejected bearer or at least one rejected data stream may not be available for the resource, an invalid QoS combination corresponding to the session data stream, a data stream set identifier, or the like. Retransmission indication information corresponding to the C1 session including the rejected bearer/data stream may be further included in the handover request acknowledgment message. The value represented by the retransmission indication information is the same as that of the above content. The retransmission indication information Y indicates that the terminal is allowed to route the rejected C1 session data stream to the supported network segment of the target base station. Therefore, more accurate information can be provided for the next handover. The rate of successful handover attempts is increasing. The rejected bearer/stream ID, the retransmission indication information, and the reason information may optionally be carried in the handover request acknowledgment message. The acknowledged session list may be represented as a list of allowed PDU sessions (list of allowed PDU sessions) or a transfer list of PDU sessions (list of PDU sessions to be forwarded).

Table 3

List of received sessions Session ID Rejected channel/stream ID Cause Information Retransmission indication information Session C1 Identifier of at least one rejected channel/data stream R3 Y Session C2 Empty character (indicates that all channel/QoS flow IDs have been received) Empty symbol Empty symbol

Further, referring to Table 4, where Table 4 is a form of a rejected session list in accordance with an embodiment of the present invention. The rejected bearer/stream ID and the retransmission indication information may optionally be transmitted in the handover request acknowledgment message. The C3 session reason information is R1 indicating that the target base station supports the network segment corresponding to the C3 session, but the resource for the network segment is unavailable. The D1 session reason information and the D2 session reason information are R2, indicating that the target base station does not support the network segment corresponding to the D1 session or the network segment corresponding to the D2 session. The Y in the retransmission indication information indicates that the terminal is allowed to route the C3 session data stream to the supported network segment of the target base station. The N in the retransmission indication information indicates that the terminal is not allowed to route the D1 session and D2 session data streams to the supported network segment of the target base station. The rejected session list may be in the form of a Session PDU Release List (Session PDU Release List) or a Session PDU Reject List (PDU Not Allowed List).

Table 4

List of rejected sessions Session ID Rejected channel/stream ID Cause Information Retransmission indication information Session C3 Identifiers of all bearers/data flows of the C3 session R1 Y Session D1 Identifiers of all bearers/data flows of session D1 R2 N Session D2 Identifiers of all bearers/data flows of the D2 session R2 N

In addition, it can be obtained that in Table 4 a list is generated based on each session ID. In another possible way, the list may be generated based on the reason information. As shown in Table 5, Table 5 is another form of a list of sessions that are rejected in accordance with an embodiment of the present invention. In this case, one piece of cause information corresponds to a plurality of session IDs, thereby reducing the amount of signaling. The rejected bearer/stream ID and the retransmission indication information may optionally be carried in the handover request acknowledgment message. The rejected session list may be in the form of a PDU Session Release List (PDU Session Release List) or a PDU Session Reject List (PDU Not Allowed List).

Table 5

List of rejected sessions Cause Information Session ID Rejected channel/stream ID Retransmission indication information R1 Session C3 Identifiers of all bearers/data flows of the C3 session Y R2 Session D1 Identifiers of all bearers/data flows of session D1 N Session D2 Identifiers of all bearers/data flows of the D2 session N

Alternatively, the handover request acknowledgment message further carries channel configuration information determined by the target base station, and the channel configuration information is used to instruct the terminal to perform channel configuration based on the configuration information.

Further, alternatively, the handover request confirmation message further includes information indicating the complete handover configuration. The handover complete configuration indication information is used to indicate that the terminal does not need to modify each original bearer. The complete handover configuration may be performed using the bearer configuration information determined by the target base station. Specifically, all original bearer configurations are removed, and the bearer configuration information determined by the target base station is stored to improve the efficiency of the bearer configuration. Alternatively, if the handover request includes the handover complete configuration indication information, the handover request confirmation message further includes the handover complete configuration indication information.

Alternatively, the handover request confirmation message further includes supported network segment information of the target base station. This helps the target base station notify the source base station of the network segment information currently supported by the target base station, thereby reducing the interaction between the source base station and the target base station.

Accordingly, the source base station receives the handover request confirmation message sent by the target base station.

304. The source base station sends a handover command to the terminal.

The source base station sends a handover command to the terminal after the source base station receives the handover request confirmation message sent by the target base station. For example, the handover command may be an RRC Connection Reconfiguration message or a handover Command message. The handover command includes at least one of a received session identifier, a received session data stream identifier, and a bearer identifier corresponding to the received session to notify the session terminal, a data stream, or a bearer to be handed over to the target base station.

Alternatively, the handover command further includes a session that is rejected by the target base station and retransmission indication information corresponding to the rejected session. Thus, the terminal determines, based on the retransmission indication information corresponding to the rejected session, whether to initiate a session setup request to the target base station for the rejected session. Alternatively, for a plurality of rejected sessions, the handover command may include retransmission indication information corresponding to each session, or the handover command may indicate that retransmission is allowed and retransmission is not allowed. This is not limited in this embodiment of the present invention.

Alternatively, if the handover request acknowledgment message includes bearer configuration information specified by the target base station, the handover command further includes bearer configuration information specified by the target base station to instruct the terminal device to perform bearer configuration on based on the configuration information. If the handover request confirmation message further includes information for specifying a complete handover configuration, the handover command further includes information for specifying a complete handover configuration to improve the efficiency of the bearer configuration.

Accordingly, the terminal device receives the handover command sent by the source base station.

305. The terminal sends a handover confirmation message to the target base station.

For example, the handover confirmation message may be a handover complete message or may be an RRC Connection Reconfiguration Complete message.

Alternatively, after the terminal device receives the handover command, random access is performed between the terminal device and the target base station to transmit a handover confirmation message to the target base station. The handover confirmation message is used to indicate that the terminal has completed the handover.

306. The target base station sends a route switch request to the core network device.

The target base station sends a route switch request to the core network device when receiving a handover confirmation message. For example, a route switch request is a route switch request. The route switch request includes a session ID that is received by the target base station so that the core network device performs the route switch in the received session.

Alternatively, the route switch request may further include a session identifier that is rejected by the target base station such that the core network device performs a release or deactivation in the rejected session.

In addition, there is an activated service and a deactivated service in the terminal device, and the core network device stores all sessions of the terminal device. Both the accepted session and the rejected session belong to the activated service. The IDs of these two sessions are sent in the route switch request so that the core network device can determine the deactivated session from all of the terminal's stored sessions. Thus, the core network device does not need to process such sessions, but only needs to process the accepted session and the rejected session, thereby improving processing efficiency.

Alternatively, the route switch request further includes specifying a network segment corresponding to a session that is rejected by the target base station, so that the core network device can compare the network segment corresponding to the rejected session with the network segment supported by the target base station and stored in core network device. Therefore, the core network device can obtain information about whether the session is rejected because the target base station does not support the network segment. If yes, the core network device subsequently starts a session release (deletion) process to reduce the amount of memory occupied by such sessions in the core network device. If not, then the core network device may subsequently initiate a session deactivation (deactivation) process so that the core network device can quickly resume the session when the session should be activated.

Alternatively, the route switch request includes reason information corresponding to the session that was rejected by the target base station. The reason information is transmitted so that the core network device can perform different processing of sessions rejected for different reasons.

Accordingly, the core network device receives the route switching request sent by the target base station.

307. The core network device performs a route switch in the received session and performs deactivation or release of the rejected session.

That the core network device performs deactivation processing in a rejected session specifically suspends the rejected session. The context corresponding to the session can be stored in the core network device so that the core network device can quickly resume the session when the session needs to be activated.

That the core network device performs releasing the rejected session is specifically as follows: the core network device releases the context corresponding to the session. For example, the AMF network element instructs the SMF network element to release the context corresponding to the session, thereby reducing the amount of memory occupied by such sessions in the core network device.

Alternatively, the core network device may perform deactivation in a rejected session because the target base station's network segment resource is not available, so that session data transmission can be resumed when the target base station's network segment is available. Compared with the release performed in a session, the time required for activation processing is shortened by re-establishing a session when the network segment of the target base station is not limited, so that data transmission of a deactivated session can be resumed more quickly.

Alternatively, the core network device may release a session that is rejected because the target base station does not support the network segment. The supported network segment of the target base station does not change for a short time, and therefore the transmission of session data cannot be resumed for a short time. In this case, if session processing is performed in a session, more storage space of the core network device is occupied, and the storage space is used inefficiently.

308. The core network device sends a route switch request response message to the target base station.

The core network device sends a route switch request response message to the target base station. The route switch request response message includes a session ID for which the route switch was successfully completed. For example, the route switch request response message is a route switch request acknowledgment or a route switch request response.

Alternatively, the route switch request response message further includes a session identifier for which the route switch is denied so that the target base station determines the result of the route switch of the core network device.

In this embodiment of the present invention, after the source base station sends a handover request to the target base station, the source base station can obtain the reason information of the session that is rejected due to the network segment of the target base station to help provide information for another session, to be requested for handover of the target base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the handover success rate.

Referring to FIG. 4, where FIG. 4 shows a communication method in accordance with an embodiment of the present invention. In this embodiment, an example is used in which the network access device is a base station. As shown in FIG. 4, the communication method refers to a terminal device, a source base station, and a target base station. Fig. 4 corresponds to the communication method used when the target base station determines that the handover has failed. The source base station is the base station that is currently establishing a communication connection with the terminal device, and the target base station is the base station to which the handover of the terminal device session is requested.

As shown in FIG. 4, the communication method includes steps 401 to 404. The following is a detailed specific description.

401. The source base station sends a handover request to the target base station.

For step 401, refer to the respective detailed descriptions of step 301 in the embodiment shown in FIG. 3. Details are not described here again.

402. The target base station performs access control based on a factor such as a network segment support state, a resource usage state, or a handover request.

The target base station performs admission control if the target base station receives a handover request sent by the source base station. Alternatively, the target base station determines the handover response message based on a factor such as the network segment designation information corresponding to each session in the handover request, the network segment support state of the target base station, or the resource usage state.

In addition, the handover response message may be a handover request confirmation message, or the handover response message is a handover failure message. In the embodiment shown in FIG. 4 describes a case where the handover response message is a handover failure message. In this case, none of the sessions requested for handover can be handed over to the target base station. Namely, the sessions requested for handover to all are sessions rejected by the target base station. The session handoff may be rejected by the target base station because the target base station does not support the network segment corresponding to the rejected session, or because the resource for the network segment corresponding to the rejected session is not available to the target base station. Therefore, the handover request confirmation message includes rejection indication information. The reject indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to a network segment from the session requested for handover. The reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, the reason information in this embodiment of the present invention may be indicated using an IE, a flag, a reason, or the like. This is not limited in this embodiment of the present invention.

For example, if the session requested for handover includes a first session and a second session, the rejected session reason information may be: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station. and corresponding to the rejected session. If the session requested for the handover includes the first session, the rejected session reason information is: The resource is not available for the network segment corresponding to the rejected session.

403: The target base station sends a handover failure message to the source base station.

The handover failure message includes cause information corresponding to the rejected session. For example, the handover failure message is a handover preparation failure message.

Alternatively, the handover failure message further includes a rejected bearer identifier or a rejected data stream identifier of the session requested for the handover. One session includes a plurality of data streams, and one bearer corresponds to at least one data stream. The rejected bearer may be a rejected session bearer, and the rejected data stream may be a rejected session data stream. For example, all bearers of a dropped session are dropped bearers, and all data streams of a dropped session are dropped data streams. The rejected bearer or rejected data stream identifier is sent to the source base station using a handover failure message so that the source base station can acknowledge the rejected bearer or rejected data stream.

Further, in this embodiment of the present invention, the handover failure message may be represented using a rejected session list. For a list, refer to all contents in Table 4 and Table 5 except for the retransmission indication information. The rejected bearer/stream ID is a possible content of the handover failure message, and it is not limited in this embodiment of the present invention.

Alternatively, if the handover response message is a handover failure message, the reject indication information may be used to indicate that the target base station does not support the network segment corresponding to any tag session. For example, if the session requested for handover includes a first session and a second session, and the source base station does not know the recently updated supported network segment by the target base station, it is likely that the target base station will not support any requested session. In this case, in an exemplary solution, the handover failure message includes rejection indication information (indicated by IE, flag, cause, or the like) and a rejected session ID. For example, in this case, referring to Table 6, the session PDU release list includes a handover reject indication value. In another possible solution, the handover failure message includes rejection indication information (indicated by IE, flag, cause, etc.). In this case, the PDU session release list in Table 6 does not need to be transmitted, and only the handover failure indication value is transmitted. Thus, the source base station determines a network segment that is not supported by the target base station.

Table 6

PDU Session to Release List Indication value (Indicator)

Alternatively, the reject indication information may be used to indicate that the target base station supports the network segment corresponding to any session in the handover request and that the target base station refuses to handover all sessions contained in the handover request. For example, if the session requested for handover includes the first session, and the resource for the network segment of the target base station corresponding to each session that is requested for handover is unavailable, in a possible solution, the handover failure message includes reject indication information (indicated by IE, flag, cause, or the like); in another possible solution, the handover failure message includes rejection indication information (indicated by IE, flag, reason, etc.) and rejected session identifier so that the source base station determines the resource usage state of the network segment corresponding to the session requested for handover, target base station.

Alternatively, the reject indication information may be used to indicate that the target base station supports the network segment corresponding to the third session but refuses to transmit the third session, and that the target base station does not support the network segment corresponding to the fourth session. The session to be handed over includes a third session and a fourth session. For example, when the source base station does not determine the supported network segment newly updated by the target base station, if the session requested by the source base station for handover includes a first session and a second session, or if the session requested by the source base station to be handed off , includes the first session, the target base station may reclassify, based on the support state and the network segment resource usage state of the target base station, the sessions requested for handover. Specifically, the source base station determines that the first session supported by the target base station may change to a session that is not supported by the target base station, and the source base station determines that the second session that is not supported by the target base station may change to a session , which is supported by the target base station. Therefore, the third session in the deviation indication information returned by the target base station may be the same or different from the first session in the handover request, and the fourth session in the deviation indication information returned by the target base station may be the same or different from the second session. in a handover request. Further, in this case, the target base station can classify sessions corresponding to the same handover rejection reason into one session type, and map sessions of that type to one piece of rejection indication information (indicated by an IE, a flag, a reason, or that similar). Namely, the handover failure message includes two pieces of failure indication information and session identifiers corresponding to two pieces of failure indication information. Alternatively, the target base station may map each rejected session to one piece of reject indication information (indicated by IE, flag, cause, or the like). Namely, the handover failure message includes an ID of at least one rejected session and session rejection information corresponding to each rejected session. Alternatively, the handover failure message includes two pieces of failure indication information. This is not limited in this embodiment of the present invention. Alternatively, for a rejected session due to a resource for a network segment of the target base station being unavailable, the rejected session identifier and indication information of the network segment corresponding to the rejected session may be added to the handover failure message to indicate to the source base station that the resource for such a network segment, the target base station is not available without using additional indication information. Thus, the source base station can determine the resource usage state of such a network segment in the target base station.

Alternatively, the reject indication information may be used to indicate that the target base station rejects the session handover execution. For example, when the session requested by the source base station for handover includes the first session and the second session, a resource for each network segment supported by the target base station is unavailable. In this case, the handover failure message includes one piece of reject indication information indicating that the target base station not only rejects a session requested for handover, but also rejects a session corresponding to another supported network segment. Thus, the source base station can acquire the resource usage states of all network segments in the target base station in a timely manner. This provides information for the handover of another session at the source base station, thereby increasing the rate of successful handover attempts.

Alternatively, the handover failure message further includes supported network segment information of the target base station. This helps the target base station notify the source base station of the network segment information currently supported by the target base station, thereby reducing the interaction between the source base station and the target base station.

404. The source base station sends an RRC connection release message to the terminal.

The source base station sends an RRC connection release message to the terminal upon determining that the handover fails, so that the terminal releases the RRC connection as soon as possible to avoid subsequent radio link failure and reduce overhead.

Alternatively, the RRC connection release message includes indication information of the network segment supported by the neighbor cell of the source cell, indication information of the network segment supported by the TA/RA to which the neighbor cell of the source cell belongs, or information of the network segment supported by the neighbor base station of the source base station. . The source cell is the cell serving the terminal when the source base station requests handover to the target base station. Thus, the original base station gets more network segments supported by the other cell or another base station. This provides information for further processing and reduces interaction signaling for obtaining network segment information between the second base station and the neighboring base station of the first base station, thereby improving the convenience of obtaining the supported network segment information of the base station.

Accordingly, the terminal receives the RRC Connection Release message and releases the RRC Connection.

In this embodiment of the present invention, after the source base station sends a handover request to the target base station, the source base station can obtain the reason information of the session that is rejected due to the network segment of the target base station to help provide information for another session that is must be requested for handover to the target base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the handover success rate.

Referring to FIG. 5, where FIG. 5 shows another communication method according to an embodiment of the present invention. For description, an example is used in which the network access device in the communication method is a base station. As shown in FIG. 5, the communication method is related to the first base station and the core network device. The following is a detailed description.

501. The first base station sends the first message to the core network device. The first message is used to obtain information indicating the supported network segment of the core network device for the PLMN.

The core network device may serve a plurality of public land mobile networks (Public Land Mobile Network, PLMN). Different PLMNs served by the same core network device may support different network segments. If different core network devices serve the same PLMN, then the network segments supported by different core network devices may differ. This is not limited in this embodiment of the present invention. For example, the first core network device may serve the first PLMN and the second PLMN. If the first core network device serves the first PLMN, the first core network device supports network segment 1, network segment 2, and network segment 3. If the first core network device serves the second PLMN, then the first core network device supports network segment 1 and network segment 4. Second the core network device may serve the first PLMN. If the second core network device serves the first PLMN, then the second core network device supports network segment 1, network segment 4, and network segment 5.

Alternatively, the first message contains a PLMN identifier, and hence the core network device returns indication information of the supported PLMN network segment indicated by the PLMN identifier served by the core network device. Alternatively, the PLMN identifier (PLMN ID) contained in the first message may be part of the first base station served PLMN or the entire first base station served PLMN.

Alternatively, the first message does not carry the identity of any PLMN, and therefore, the core network device can send supported network segment indication information for each PLMN served by the core network device. For example, if the core network device serves three PLMNs, then the core network device sends to the first base station the supported network segment indication information for each PLMN served by the core network device.

Accordingly, the core network device receives the first message from the first base station.

502. The core network device sends a second message to the first base station. The second message includes information indicating a supported network segment for the PLMN served by the core network device.

The supported network segment of the core network device to serve various PLMNs may be pre-configured by the network management device. For example, the network management device is Operation Administration and Maintenance (OAM), and the supported network segment may be an updated network segment (eg, OAM is updating for the core network or is updating for another reason). This is not limited in this embodiment of the present invention.

The first base station receives the supported network segment indication information for the PLMN served by the core network device, thereby helping to provide information when the first base station selects the core network device for the terminal device to more accurately select the core network device for the terminal device session.

For example, the terminal accesses the first PLMN, and the network segment corresponding to the session to be served by the core network device is network segment 4. If the first core network device serves the first PLMN, then the first core network device supports network segment 1, network segment 2 and network segment 3. If the first core network device serves the second PLMN, then the first core network device supports network segment 1 and network segment 4. If the second core network device serves the first PLMN, then the second core network device supports network segment 1, network segment 4 and network segment 5. If the supported network segment of the first core network device is not sent back with PLMN granularity, the first core network device supports network segment 1, network segment 2, network segment 3, and network segment 4, and the second core network device supports network segment 1 , network segment 4 and network segment 5 Therefore, it is highly likely that the first base station selects the first core network device to serve the terminal device session. However, the first core network device does not support network segment 4 when the first core network device serves the first PLMN, and therefore, a core network device selection error occurs. However, if the supported network segment of the core network device is fed back for each PLMN (with PLMN granularity), the case where the first base station selects the first core network device for the terminal session can be avoided, and the core network device selection accuracy for the terminal session can be increased.

Accordingly, the first base station receives the second message sent by the core network device.

Alternatively, if the first message contains a PLMN ID, the core network device may send, to the first base station, supported network segment indication information for the PLMN (indicated by the PLMN ID) served by the core network device; or, the core network device sends to the first base station the supported network segment indication information for all PLMNs served by the core network device.

Alternatively, if the first message does not contain a PLMN identifier, then the core network device may send back supported network segment indication information for each PLMN served by the core network device.

Alternatively, there is no communication interface between the first base station and the core network device. For example, the communication interface between the first base station and the core network device is represented as N2 or NG. The N2 interface is used as an example. The first message sent by the first base station to the core network device may be an N2 interface setup request message or a base station configuration update message (eg, gNB configuration update). The first base station receives an N2 interface setup failure message or a base station configuration update failure message (eg gNB configuration update failure) from the core network device. The core network device may send, using the N2 interface setup failure message or the update failure message, the supported network segment indication information for the PLMN served by the core network device. Thus, in the setup process, the first base station can also acquire the supported network segment indication information for the PLMN served by the core network device, thereby reducing the interaction for obtaining the supported network segment and increasing the acquisition rate of the network segment indication information. In another example, the first message sent by the first base station to the core network device is also an N2 interface setup request or a base station configuration update message. The first base station receives an N2 interface setup response message or a base station configuration update acknowledgment message (eg, a gNB configuration update ACK) from the core network device. The core network device may send, using the N2 interface setup response message or the core network device configuration update confirmation message, the supported network segment indication information for the PLMN served by the core network device. Thus, the first base station can obtain the indication information of the supported PLMN network segment served by the core network device, thereby improving the convenience of obtaining the network segment indication information.

Alternatively, there is a communication interface between the first base station and the core network device. For example, the first message is a get request. The core network device may send, using the response message, indication information of the supported PLMN network segment served by the core network device. In another example, the first message sent by the first base station to the core network device may be a base station configuration update message (eg, gNB configuration update). The first base station receives a base station configuration update failure message (eg, gNB configuration update error) from the core network device. The core network device may send, using the update failure message, indication information of the supported network segment of the served PLMN of the core network device. In another example, if the first message sent by the first base station to the core network device is also a base station configuration update message, the first base station receives a base station configuration update acknowledgment message (e.g., gNB configuration update ACK) from the core network device. The core network device may send, using the core network device configuration update confirmation message, indication information of the supported PLMN network segment served by the core network device. Thus, the first base station can obtain the indication information of the supported PLMN network segment served by the core network device, thereby improving the convenience of obtaining the network segment indication information.

It should be understood that there is no necessary causal relationship or sequence between step 501 and step 502. For example, step 502 may be implemented independently as long as the core network device determines, before step 502, the supported network segment indication information for the PLMN served by the core network device. For example, the core network device may actively implement step 502 when determining that the updated supported network segment of the served PLMN of the core network device has been updated. In this case, the second message is an AMF configuration update message (eg, AMF configuration update) to notify the first base station of the updated supported network segment indication information for the PLMN served by the core network device.

It should be noted that in this embodiment of the present invention, the PLMN served by the core network device can also be understood as the PLMN supported by the core network device, and this is not limited in this embodiment of the present invention.

In this embodiment of the present invention, the first base station can obtain, using the core network device, the supported network segment indication information for the PLMN served by the core network device, and feed back at the PLMN granularity the supported network segment by the core network device, to improve the selection accuracy of the first base station. core network device for the endpoint session.

Referring to FIG. 6, where FIG. 6 shows another communication method according to an embodiment of the present invention. In this embodiment, an example in which the network access device is a base station is used to describe. As shown in FIG. 6, the communication method refers to a terminal device, a source base station, a target base station, and a core network device. Fig. 6 corresponds to the communication method used when the core network device determines that handover preparation has failed. The source base station is the base station that is currently establishing a communication connection with the terminal device. The target base station is the base station that is requested to handoff the terminal session.

As shown in FIG. 6, the communication method includes steps 601 to 606. The following is a detailed description.

601. The source base station sends a first handover request to the core network device.

A communication interface such as an N2 interface or an NG interface is installed between the source base station and the core network device. Therefore, the source base station and the core network device can communicate with each other. The first handover request is used to request handover of the terminal device session from the source base station to the target base station. For example, the first handover request is the requested handover. The first handover request includes information about the target base station and a session ID that is requested for the handover. The core network device may determine, using the target base station information, the base station/cell for which the terminal device session handoff is to be performed. The core network device may determine, using the session ID requested for handover, the session to be handed over. There may be one or more sessions requested for handover, and different sessions may correspond to different network segments. Different network segments correspond to different network segment designation information.

Alternatively, the target base station information includes at least one of a target base station base station ID, a target base station central unit ID, a target base station distributed unit ID, a target base station physical cell ID, or a target base station global cell ID. .

Alternatively, the first handover request further includes information indicating a network segment corresponding to the session requested for the handover. Thus, the core network device can directly determine the network segment corresponding to the session to be handed over, thereby saving time used to search for the network segment corresponding to the session, reducing the handover delay, and increasing the handover success rate. It is understood that the first handover request may not include the network segment designation information corresponding to the session requested for the handover. This is not limited in this embodiment of the present invention.

For example, the core network device is an AMF network element. If the AMF network element cannot store the network segment indication information corresponding to the session, then the network segment indication information corresponding to each session is transmitted in the first handover request.

Alternatively, the first session includes a plurality of data streams. For example, the data flow is a traffic flow or a QoS flow (QoS flow). The first handover request further includes a data flow identifier (for example, the data flow identifier includes a QoS flow identifier) to be established and which corresponds to the session, and further includes QoS information (for example, priority information) corresponding to each from a plurality of session data streams. The core network apparatus includes an AMF network element and an SMF network element on the core network side. The AMF network element first receives the first handover request message sent by the source base station, the AMF network element sends the second handover request message to the target base station. The second handover request message must include the identifier of the session data flow to be transmitted and the QoS information of the data flow. However, the information is not stored in the AMF network element. Therefore, if information is transmitted in the first handover request, then the AMF network element does not need to receive information from the SMF network element, thereby saving search time, reducing the handover delay, and improving handover efficiency.

Alternatively, the first handover request further includes aggregate maximum bit rate (AMBR) information corresponding to the session, such as signed AMBR information. The target base station can perform traffic control in the data stream based on this piece of information, but the information must be sent by the core network device to the target base station. In this case, the core network device includes an AMF network element and an SMF network element on the core network side. Since the AMF network element does not store this piece of information, the information is added to the first handover request to reduce the time used by the network element to search for the network element SMF for AMF information. This can save search time, reduce handover delay, and improve handover efficiency.

Alternatively, the first handover request further includes the first indication information, and the indication information indicates that the source base station does not determine or knows the supported network segment of the target base station, so that the core network device obtains information that the source base station does not know information about the supported network segment of the target base station. Therefore, information about the supported network segment of the target base station can be added to the first handover response message. This reduces the interaction between the source base station and the target base station, and improves the efficiency of obtaining network segment information.

Alternatively, the target base station may be a base station that has a communication interface with the source base station, or may be a base station that does not have a communication interface with the source base station. Alternatively, the first handover request may include second indication information indicating that there is no communication interface between the source base station and the target base station. This helps the core network device to communicate supported network segment information to the target base station.

Alternatively, the source base station selects one of the plurality of base stations that have a communication interface with the source base station as the target base station. In addition, the determined target base station supports network segments corresponding to all or some of the sessions requested for handover, so that a handover failure caused by the target base station not supporting network segments of all sessions requested for handover is avoided, and the number handover failures are reduced to increase the rate of successful handover attempts.

Alternatively, if the source base station receives the measurement report sent by the terminal, the source base station may select the target base station based on the measurement report and execute step 601 to send a handover request to the target base station. The measurement report includes a measurement report value of at least one of the cell and the base station. Alternatively, if the measurement report includes a cell measurement report value, the cell may be the cell of the source base station or the cell of another base station. If the measurement report includes a base station measurement report value, then the base station may be the original base station or another base station. Alternatively, the number of cells and the number of base stations contained in the measurement report are not limited in this embodiment of the present invention.

602. The core network device determines the indication information of the network segment corresponding to the session requested for handover.

Step 602 is an optional step. If the first handover request does not include the network segment indication information corresponding to the session, the core network device may search, based on the session ID requested for the handover, a stored correspondence between the session ID and the network segment indication information for the network segment indication information corresponding to the session requested for handoff. The mapping stored in the core network device may include the ID or IDs of one or more sessions of the terminal device and the indication information of the corresponding network segment.

If the first handover request includes the indication information of the network segment corresponding to the session ID requested for the handover, the core network device can directly determine the indication information of the network segment corresponding to the session requested for the handover. The time used by the core network device to search for the indication information of the network segment corresponding to the session to be handed over can be reduced.

In addition, the first handover request may include information about the target base station, and the core network device determines, based on the information about the target base station, information about the supported network segment of the target base station. The network segment information includes information on specifying a supported network segment. In a specific example, the session requested for the handover is set to an E1 session. When there is a communication interface between the target base station and the core network device, if the core network device has obtained information about the first supported network segment of the target base station, the core network device can directly determine the indication information of the first supported network segment of the target base station. If the core network device does not obtain information about the first supported network segment of the target base station, the core network device can obtain indication information of the first supported network segment of the target base station from the target base station. In addition, the core network device can determine whether the indication information of the first supported network segment of the target base station includes indication information of the second network segment corresponding to the E1 session. If the target base station's first supported network segment indication information includes the second network segment indication information corresponding to the E1 session, it indicates that the target base station supports the network segment corresponding to the E1 session. If the target base station's first supported network segment indication information does not include the second network segment indication information corresponding to the E1 session, it indicates that the target base station does not support the network segment corresponding to the E1 session.

Then, if the indication information of the first supported network segment of the target base station does not include the indication information of the second network segments corresponding to all sessions requested for handover, the core network device may determine that the target base station does not support the network segment corresponding to the session that subject to handover. The core network device may perform step 605 in FIG. 6, and the core network device sends a first handover response message to the source base station. In this case, the first handover response message may be the first handover failure message. The first handover failure message includes reject indication information used to indicate that the target base station does not support network segments corresponding to all sessions requested for handover. Alternatively, the deviation indication information may be indicated using an IE, a flag, a reason, and the like, and this is not limited in this embodiment of the present invention.

Alternatively, if the target base station supports network segments corresponding to all or some of the sessions requested for handover, the core network device performs step 603 in FIG. 6, and the core network device sends a second handover request to the target base station.

603. The core network device sends a second handover request to the target base station.

For example, the second handover request is a handover request. The second handover request includes a session ID corresponding to a session that is requested for handover and a network segment designation information corresponding to a session that is requested for handover.

Alternatively, the second handover request includes the session IDs of all sessions requested by the source base station to be handed over and the network segment designation information corresponding to each session.

Alternatively, after the core network device performs step 602, the core network device may classify the sessions requested by the source base station for handover into a first session and a second session. The network segment corresponding to the first session is supported by the target base station. The network segment corresponding to the second session is not supported by the target base station. Also, the second handover request may only include the first session identifier and the indication information of the network segment corresponding to the first session. Or, the second handover request includes a first session identifier, a second session identifier, network slice indication information corresponding to the first session, and network slice indication information corresponding to the second session. This is not limited in the embodiments of the present invention.

Accordingly, the target base station receives the second handover request.

604: The target base station sends a second handover failure message to the core network device.

The target base station receives the second handover request from the core network device and determines whether the target base station can serve the session included in the second handover request. If the target base station is unable to serve any session, the second handover response message sent to the core network device at 604 in FIG. 6 may be a second handover failure message, such as handover request failure or handover failure. The second handover failure message may also be a handover preparation failure message (handover preparation failure). The second handover failure message includes cause information corresponding to the rejected session.

In addition, the rejected session reason information may be: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

The description of the specific implementation of the second handover failure message in this embodiment of the present invention may be made with reference to the specific description of the handover failure message at step 403 in the embodiment shown in FIG. 4. Details are not described here again.

Accordingly, the core network device receives the second handover failure message sent by the target base station.

605. The core network device sends a first handover response message to the source base station.

The core network device sends a first handover response message to the source base station. In this embodiment, the first handover response message is the first handover failure message. For example, the first handover failure message is a handover preparation failure message. The first handover response message includes rejection indication information. The reject indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to a network segment from the session requested for handover.

Alternatively, the first handover failure message includes a rejected session ID and reason information corresponding to the rejected session ID.

Alternatively, if the core network device sends to the target base station the IDs of all sessions requested by the source base station for handover, the rejected session ID and the reason information corresponding to the rejected session contained in the first handover failure message are the same as the rejected session ID and reason information corresponding to the rejected session contained in the second handover failure message.

Alternatively, if the core network device sends the first session identifier to the target base station in all sessions requested by the source base station for handover, and the first session is a session that is in the sessions that are requested for handover and whose corresponding network segment is supported by the target base station, the first handover failure message includes a first rejected session ID, reason information corresponding to the first rejected session, a second rejected session ID, and cause information corresponding to the second rejected session. The first rejected session is the session that is rejected and that is contained in the second handover failure message, and the second rejected session is the session that is in the sessions requested for handover and whose corresponding network segment is not supported by the target base station. The second rejected session ID and the reason information corresponding to the second rejected session are determined by the core network device.

Alternatively, the core network device adds information about the supported network segment of the target base station to the first handover response message, for example, if the first handover request includes first indication information indicating that the source base station does not know the supported network segment of the target base station , or the core network device determines, based on the indication that is transmitted in the first handover request, and which indicates the absence of a communication interface between the source base station and the target base station, the source base station that does not have information about the supported network segment of the target base station . This reduces the interaction between the source base station and the target base station, and improves the efficiency of obtaining network segment information.

606. Alternatively, the source base station sends an RRC connection release message to the terminal.

The description of step 606 may be made with reference to the detailed description of step 404 in the embodiment shown in FIG. 4. Details are not described here again.

In this embodiment of the present invention, after the source base station sends a handover request to the core network device, the source base station can obtain the reason information of the session that the target base station rejects due to the network segment to help provide information for another session, which must be requested for handover to the target base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the rate of successful handover attempts.

Referring to FIG. 7, where in FIG. 7 shows another communication method according to an embodiment of the present invention. In this embodiment, an example in which the network access device is a base station is used for description. As shown in FIG. 7, the communication method refers to a terminal device, a source base station, a target base station, and a core network device. Fig. 7 corresponds to the communication method used when the core network device determines that the handover is successful. The source base station is the base station that is currently establishing a communication connection with the terminal device, and the target base station is the base station to which the handover of the terminal device session is requested.

As shown in FIG. 7, the communication method includes steps 701 to 707. The following is a detailed description.

701. The source base station sends the first handover request to the core network device.

702. The core network device determines the indication information of the network segment corresponding to the session requested for handover.

703. The core network device transmits a second handover request to the target base station.

Description of steps 701-703 may be given with reference to the detailed description of steps 601-603 in the embodiment shown in FIG. 6. Details are not described here again.

704. The target base station sends a second handover request acknowledgment message to the core network device.

The second handover request acknowledgment message includes a received session identifier. For example, the second handover request acknowledgment message is a handover request acknowledgment.

Alternatively, the first handover response message may further include a rejected session identifier and reason information corresponding to the rejected session.

Alternatively, the second handover request confirmation message further includes retransmission indication information corresponding to the rejected session. The retransmission indication information is used to indicate whether the terminal device is allowed to route the rejected session data stream to the supported network segment of the target base station. For example, the rejected session is session B1, and session B1 corresponds to network segment 1. The reason information for rejected session B1 can be: the target base station does not support network segment 1 corresponding to session B1, or the target base station supports network segment 1, but the resource is not available. for network segment 1. Regardless of the reason for rejecting session B1, if the target base station supports network segment 2 and the traffic of session B1 is routed to network segment 2, data transfer can also be realized. In this case, the target base station determines that the retransmission indication information corresponding to the B1 session: the terminal device is allowed to route the data flow of the B1 session to the network segment 2 supported by the target base station. In addition, if the network segment to which the B1 session traffic can be directed is not present in the target base station, the target base station determines that the retransmission indication information corresponding to the B1 session is: the terminal is not allowed to route the B1 session traffic to supported network segment of the target base station.

Alternatively, the handover request acknowledgment message further includes a rejected bearer ID or a rejected session data stream ID of the session requested for the handover. A detailed description may be given with reference to a detailed description of step 303 in the embodiment shown in FIG. 3. Details are not described here again.

The second handover request acknowledgment message in this embodiment of the present invention may refer to the handover request acknowledgment message in the embodiment shown in FIG. 3. The second handover request acknowledgment message includes an accepted session ID, a rejected session ID, and reason information corresponding to the rejected session. A second handover request acknowledgment message is sent to the core network device.

705. The core network device sends a first handover request acknowledgment message to the source base station.

The core network device transmits the first handover response message to the source base station. In this embodiment, the first handover response message is the first handover request acknowledgment message. For example, the first handover request acknowledgment message is a Handover command. The first handover request acknowledgment message includes a received session identifier.

Alternatively, the first handover response message may further include a rejected session identifier and reason information corresponding to the rejected session.

Alternatively, if the core network device sends to the target base station the identifiers of all sessions requested by the source base station for handover, the rejected session identifier and the reason information corresponding to the rejected session contained in the first handover request acknowledgment message are the same as the rejected session identifier. session and reason information corresponding to the rejected session, which is contained in the second handover request acknowledgment message.

Alternatively, if the core network device sends to the target base station the first session identifier in all sessions requested by the source base station for handover and the first session is the session that is in the sessions that are requested for handover and whose corresponding network segment supported by the target base station, the first handover request acknowledgment message includes a first rejected session ID, reason information corresponding to the first rejected session, a second rejected session ID, and reason information corresponding to the second rejected session. The first rejected session is the session that is rejected and that is contained in the second handover request acknowledgment message, and the second rejected session is the session that is in the sessions requested for handover and whose corresponding network segment is not supported by the target base station. The second rejected session ID and the reason information corresponding to the second rejected session are determined by the core network device.

Alternatively, the core network device adds information about the supported network segment of the target base station to the first handover response message. For example, the first handover request includes first indication information indicating that the source base station does not know the supported network segment of the target base station, or the core network device determines based on the indication carried in the first handover request, and this indicates the absence of a communication interface between the source base station and the target base station, such that the source base station does not know the supported network segment of the target base station. This reduces the interaction between the source base station and the target base station, and improves the efficiency of obtaining the network segment indication information.

706. The source base station transmits a handover command to the terminal.

707. The terminal sends a handover confirmation message to the target base station.

The description of step 706 and step 707 can be understood from the detailed description of step 304 and step 305 in the embodiment shown in FIG. 3. Details are not described here again.

In this embodiment of the present invention, after the source base station sends a handover request to the core network device, the source base station can obtain session reason information that is rejected by the target base station due to the network segment to help provide information for another session, to be requested for handover of the target base station. When performing handover of a session corresponding to the same network segment from the source base station, the source base station can directly determine whether the session can be handed over to the target base station, thereby increasing the handover success rate.

Referring to FIG. 8, where FIG. 8 is a block diagram of a base station according to an embodiment of the present invention. The base station may be a source base station and is configured to implement the embodiment of FIG. 3 or fig. 4. As shown in FIG. 8 source base station includes:

a transmission unit 801, configured to send a handover request to a target base station, where the handover request is used to request handover of a session of the terminal device from the source base station to the target base station, and the handover request includes a session identifier that is requested for handover, and indication information of the network segment corresponding to the session; and

a receiving unit 802, configured to receive a handover response message from the target base station, where the handover response message includes rejection indication information, and rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment, from the session that is being requested for handoff. Alternatively, the session requested for the handover includes the first session, or the session requested for the handover includes the first session and the second session.

The network segment corresponding to the first session is supported by the target base station, and the network segment corresponding to the second session is not supported by the target base station.

Alternatively, the reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, if the handover response message is a handover request confirmation message, then the handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station, and retransmission indication information corresponding to the session is used to indicate Whether the terminal is allowed to route the rejected session data stream to the supported network segment of the target base station.

Alternatively, the source base station sends a handover command to the terminal if the handover response message is a handover request acknowledgment message, where the handover command includes retransmission indication information corresponding to the session that was rejected by the target base station.

Alternatively, if the handover response message is a handover request acknowledgment message, the handover request acknowledgment message further includes a rejected bearer ID or a rejected session data stream ID of the session requested for the handover.

Alternatively, the transmission unit 801 is further configured to send an RRC release message of the radio resource control connection to the terminal device if the handover response message is a handover failure message.

Alternatively, the RRC connection release message includes source cell neighbor cell designation information, network segment designation information supported by the TA/RA to which the source cell's neighbor cell belongs, or network segment information supported by the source base station's neighbor base station.

It can be understood that the description of specific implementations and the corresponding benefits of the functional blocks contained in the base station in FIG. 8 is understood with reference to the specific description of the above embodiment in FIG. 3 or fig. 4. Details are not described here again.

In the present invention, the transmitting unit may be a transmitter and the receiving unit may be a receiver.

Referring to FIG. 9, where FIG. 9 is a block diagram of a base station according to an embodiment of the present invention. The base station may be a target base station and is configured to implement the embodiment of FIG. 3 or fig. 4. As shown in FIG. 9, the target base station includes:

a receiving unit 901, configured to receive a handover request from a source base station, where the handover request is used to request handover of a session of the terminal device from the source base station to the target base station, and the handover request includes a session ID that is requested for handover, and indication information of the network segment corresponding to the session; and

a transmission unit 902, configured to send a handover response message to a source base station, where the handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station due to network segment, from the session that is being requested for handoff.

Alternatively, the session requested for the handover includes the first session, or the session requested for the handover includes the first session and the second session.

The network segment corresponding to the first session is supported by the target base station, and the network segment corresponding to the second session is not supported by the target base station.

Alternatively, the cause information is that: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, the handover response message further includes retransmission indication information corresponding to a session that is rejected by the target base station, and retransmission indication information corresponding to the session is used to indicate whether the router is allowed to route to the network segment supported by the target base station. base station, rejected session data stream.

Alternatively, if the handover response message is a handover request acknowledgment message, the handover request acknowledgment message further includes a rejected bearer ID or a rejected session data stream ID of the session requested for the handover.

Alternatively, the receiving unit 901 is further configured to receive a handover confirmation message from the terminal.

The transmission unit 902 is further configured to transmit the route switch request to the core network device, where the route switch request includes a session ID that is accepted by the target base station and a session ID that is rejected by the target base station.

The receiving unit 901 is further configured to receive a route switch request response message from the core network device, where the route switch request response message includes a session identifier for which the route switch was successfully completed.

Alternatively, the route switch request further includes information indicating the network segment corresponding to the session that is rejected by the target base station.

Alternatively, the route switch request further includes reason information corresponding to the session that was rejected by the target base station.

It can be understood that the description of the specific implementations and the corresponding benefits of the functional blocks contained in the base station in FIG. 9 can be understood from the specific descriptions of the above embodiment in FIG. 3 or fig. 4. Details are not described here again.

Referring to FIG. 10, where FIG. 10 is a block diagram of a core network device according to an embodiment of the present invention. The core network device is configured to implement the embodiment of FIG. 4. As shown in FIG. 10, the core network device includes:

a receiving unit 1001, configured to receive a route switch request from a target base station, where the route switch request includes a session ID that is received by the target base station and a session ID that is rejected by the target base station;

a processing unit 1002, configured to perform a route switch in the received session and perform deactivation or release of the rejected session; and

a transmission unit 1003, configured to transmit a route switch request response message to a target base station, where the route switch request response message includes a session identifier for which the route switch was successfully completed.

Alternatively, the route switch request further includes information indicating a network segment corresponding to the session that is rejected by the target base station.

Alternatively, the route switch request includes reason information corresponding to the session that was rejected by the target base station.

Alternatively, the reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

It will be appreciated that the description of the specific implementations and corresponding benefits of the functional blocks contained in the core network device of FIG. 10 can be understood with reference to the specific description of the above embodiment in FIG. 4. Details are not described here again.

In the present invention, the processing unit may be implemented in the form of a processor.

Referring to FIG. 11, where Fig. 11 is a block diagram of a base station according to an embodiment of the present invention. The base station may be the first base station and is configured to implement the embodiment of FIG. 5. As shown in FIG. 11, the base station includes:

a transmission unit 1101, configured to transmit a first message to the core network device, where the first message is used to obtain information about a supported network segment of the core network device for the PLMN; and

a receiving unit 1102, configured to receive a second message from the core network device, where the second message includes information about a supported PLMN network segment served by the core network device.

It can be understood that the description of the specific implementations and the corresponding benefits of the functional blocks contained in the base station in FIG. 11 is understood with reference to the specific description of the above embodiment in FIG. 5. Details are not described here again.

Referring to FIG. 12, where FIG. 12 is a block diagram of a core network device according to an embodiment of the present invention. The core network device is configured to implement the embodiment of FIG. 5. As shown in FIG. 12, the core network device includes:

a receiving unit 1201, configured to receive a first message from the first base station, where the first message is used to obtain information about a supported network segment of a core network device for the PLMN; and

a transmission unit 1202, configured to transmit a second message to the first base station, where the second message includes information about the supported PLMN network segment served by the core network device.

It can be understood that the description of specific implementations and corresponding benefits of the functional blocks contained in the core network device of FIG. 12 is clear from the specific description of the above embodiment in FIG. 5. Details are not described here again.

Referring to FIG. 13, where FIG. 13 is a block diagram of a base station according to an embodiment of the present invention. The base station may be a source base station and is configured to implement the embodiment of FIG. 6 or FIG. 7. As shown in FIG. 13, the source base station includes:

a transmission unit 1301 configured to transmit a first handover request to a core network device, where the first handover request is used to request handover of a terminal device session from a source base station to a target base station, and the first handover request includes information about the target the base station and the session ID that is requested for the handover; and

a receiving unit 1302, configured to receive a first handover response message from a core network device, where the first handover response message includes rejection indication information, and rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station from -for the network segment from the session that is requested for handoff.

Alternatively, the reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, if the first handover response message is the first handover request acknowledgment message, the first handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station and retransmission indication information corresponding to the session to indicate whether the end device is allowed to route the rejected session data stream to the supported network segment of the target base station.

Alternatively, the transmission unit 1301 is further configured to send a handover command to the terminal if the first handover response message is the first handover request acknowledgment message, where the handover command includes retransmission indication information corresponding to a session that is rejected by the target. base station.

Alternatively, if the first handover response message is the first handover request acknowledgment message, the first handover request acknowledgment message further includes a rejected bearer ID or a rejected session data stream ID of the session requested for the handover.

Alternatively, the transmission unit 1301 is further configured to send an RRC connection release message to the terminal if the first handover response message is the first handover failure message.

Alternatively, the RRC connection release message includes indication information of a network segment supported by the neighbor cell of the source base station, information of indication of the network segment supported by the TA/RA to which the neighbor cell of the source base station belongs, or information of the network segment supported by the neighbor base station. original base station.

Alternatively, if the first handover response message is the first handover request acknowledgment message, the first handover request acknowledgment message further includes supported network segment information of the target base station.

Alternatively, the first handover request further includes information indicating a network segment corresponding to the session requested for the handover.

Alternatively, the first handover request further includes a session flow identifier of a session to be requested for handover and to be established, and QoS information corresponding to the data flow.

Alternatively, the first handover request further includes cumulative maximum bit rate, AMBR, information corresponding to the session.

It will be appreciated that the presentation of the specific implementations and associated benefits of the functional blocks contained in the base station in FIG. 13 is clear from the specific descriptions of the above embodiment in FIG. 6 or FIG. 7. Details are not described here again.

Referring to FIG. 14, where FIG. 14 is a block diagram of a base station according to an embodiment of the present invention. The base station may be a target base station and is configured to implement the embodiment of FIG. 6 or FIG. 7. As shown in FIG. 14, the target base station includes:

a receiving unit 1401, configured to receive a second handover request from a core network device, where the second handover request includes a session identifier and a network segment designation information corresponding to the session; and

a transmission unit 1402, configured to send a second handover response message to the source base station, where the second handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station from -for the network segment from the session that is requested for handoff.

Alternatively, the session in the second handover request is the first session, or the session in the second handover request is the first session and the second session.

The network segment corresponding to the first session is supported by the target base station and the network segment corresponding to the second session is not supported by the target base station.

Alternatively, the reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, if the second handover response message is a second handover request acknowledgment message, the second handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station and retransmission indication information corresponding to the session for an indication of whether the end device is allowed to route the rejected session data stream to the supported network segment of the target base station.

Alternatively, if the second handover response message is a second handover request acknowledgment message, the second handover request acknowledgment message further includes a rejected bearer identifier or a rejected session data stream identifier included in the second handover request.

It can be understood that the presentation of specific implementations and the corresponding benefits of the functional blocks contained in the base station in FIG. 14 is clear from the specific descriptions of the above embodiment in FIG. 6 or FIG. 7. Details are not described here again.

Referring to FIG. 15, where FIG. 15 is a block diagram of a core network device according to an embodiment of the present invention. The core network device is configured to implement the embodiment of FIG. 6 or FIG. 7. As shown in FIG. 15, the core network device includes:

a receiving unit 1501, configured to receive a first handover request from a source base station, where the first handover request is used to request handover of a session of the terminal device from the source base station to the target base station, and the first handover request includes information about the target the base station and the session ID that is requested for the handover; and

a transmission unit 1502, configured to transmit the first handover response message to the source base station, where the first handover response message includes rejection indication information, and the rejection indication information is used to indicate reason information corresponding to a session that is rejected by the target base station from -for the network segment from the session that is requested for handoff.

Alternatively, the reason information is: the target base station does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target base station and corresponding to the rejected session.

Alternatively, if the first handover response message is the first handover request acknowledgment message, the first handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station and retransmission indication information corresponding to the session for an indication of whether the end device is allowed to route the rejected session data stream to the supported network segment of the target base station.

Alternatively, if the first handover response message is the first handover request acknowledgment message, the first handover request acknowledgment message further includes a rejected bearer ID or a rejected session data stream ID of the session requested for the handover.

Alternatively, if the first handover response message is the first handover request acknowledgment message, the first handover request acknowledgment message further includes supported network segment information of the target base station or supported network segment indication information of the TA/RA to which the cell belongs. target base station.

Alternatively, the first handover request further includes information indicating a network segment corresponding to the session that is requested for the handover.

Alternatively, the first handover request further includes a session flow identifier that is requested to be transmitted and to be established, and QoS information corresponding to the data flow.

Alternatively, the first handover request further includes cumulative maximum bit rate AMBR information corresponding to the session.

Alternatively, the transmission unit 1502 is further configured to send a second handover request to the target base station, where the second handover request includes a session identifier and network segment designation information corresponding to the session.

The receiving unit 1501 is further configured to receive a second handover response message from the target base station, where the second handover response message includes deviation indication information.

Alternatively, the session in the second handover request is the first session, or the session in the second handover request is the first session and the second session.

The network segment corresponding to the first session is supported by the target base station, and the network segment corresponding to the second session is not supported by the target base station.

Alternatively, if the second handover response message is a second handover request acknowledgment message, the second handover response message further includes retransmission indication information corresponding to the session that is rejected by the target base station and retransmission indication information corresponding to the session for an indication of whether the end device is allowed to route the rejected session data stream to the supported network segment of the target base station.

Alternatively, if the second handover response message is a second handover request acknowledgment message, the second handover request acknowledgment message further includes a rejected bearer identifier or a rejected session data stream identifier included in the second handover request.

It can be understood that the presentation of specific implementations and corresponding benefits of the functional blocks contained in the core network device of FIG. 15 is clear from the specific descriptions of the above embodiment in FIG. 6 or FIG. 7. Details are not described here again.

In the present invention, each determination unit may be implemented in the form of a processor.

Referring to FIG. 16, where FIG. 16 is a block diagram of a terminal device according to an embodiment of the present invention. The terminal may be a terminal and is configured to implement the embodiment of FIG. 4 or FIG. 6. As shown in FIG. 16, the terminal device includes:

a receiving unit 1601, configured to receive an RRC release message of the radio resource control connection from the source base station; and

a processing unit 1602, configured to release an RRC connection, where the RRC connection release message includes information of a supported network segment indication of a neighbor cell of a source cell, information of a supported network segment of a TA/RA to which a neighbor cell of a source cell belongs, or information of a supported network segment segment of the neighbor base station of the source base station.

It can be understood that the presentation of specific implementations and the corresponding benefits of the functional blocks contained in the terminal device in FIG. 16 is clear from the specific descriptions of the above embodiment in FIG. 4 or FIG. 6. Details are not described here again.

The base station in the embodiment shown in FIG. 8, fig. 9, fig. 11, fig. 13 or FIG. 14 may be implemented by the base station 1700 shown in FIG. 17. As shown in FIG. 17, where FIG. 17 is a block diagram of another base station according to an embodiment of the present invention. Base station 1700 shown in FIG. 17 includes a processor 1701 and a transceiver 1702. The transceiver 1702 is configured to support communications between the base station 1700 and the core network device or other base station in the above embodiments. The processor 1701 is communicatively connected to the transceiver 1702, for example, connected to the transceiver 1702 using a bus. The base station 1700 may further include a memory 1703. The memory 1703 is configured to store data and program code that is executed by the base station 1700, and the processor 1701 is configured to execute application code stored in the memory 1703 to implement actions performed by the base station. station provided in any of the embodiments shown in FIG. 3 - 7.

It should be noted that, in an actual implementation, a base station may include one or more processors, and the structure of the base station 1700 is not a limitation to this embodiment of the present invention.

The processor 1701 may be a central processing unit (CPU), a network processor (NP), a chip, or any combination thereof. The microcircuit may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

Memory 1703 may include volatile memory, such as random access memory (RAM). Alternatively, memory 1703 may include non-volatile memory such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive. (solid-state drive, SSD). Alternatively, memory 1703 may include a combination of the above types of memory.

An embodiment of the present invention further provides a computer storage medium, and the computer storage medium may be configured to store instructions of the computer software used by the base station in the embodiment shown in FIG. 8, fig. 9, fig. 11, fig. 13 or FIG. 14. The computer software instruction includes a program that is for the base station to execute the above embodiment. The storage medium includes, but is not limited to, flash memory, a hard drive, and a solid state drive.

An embodiment of the present invention further provides a computer program product. When started by a computing device, the computing product may implement the communication method designed for the base station in the embodiment of FIG. 8, fig. 9, fig. 11, fig. 13 or FIG. fourteen.

The core network device shown in FIG. 10, fig. 12 or FIG. 15 may be implemented with the core network device 1800 shown in FIG. 18. As shown in FIG. 18, where FIG. 18 is a block diagram of another core network device according to an embodiment of the present invention. Core network device 1800 shown in FIG. 18 includes a processor 1801 and a transceiver 1802. The transceiver 1802 is configured to support communications between the core network device 1800 and the base station in the above embodiments. Processor 1801 is communicatively coupled to transceiver 1802, for example, coupled to transceiver 1802 using a bus. Core network device 1800 may further include a memory 1803. Memory 1803 is configured to store data and program code that is executed by core network device 1800, and processor 1801 is configured to execute application program code stored in memory 1803 to implement actions performed by core network device provided in any of the embodiments shown in FIG. 4-FIG. 7.

It should be noted that in an actual implementation, the core network device may include one or more processors, and the structure of the core network device 1800 is not a limitation to this embodiment of the present invention.

Processor 1801 may be a CPU, NP, chip, or any combination thereof. The microcircuit may be an ASIC, a PLD, or a combination thereof. The PLD may be CPLD, FPGA, GAL, or any combination thereof.

Memory 1803 may include volatile memory such as RAM. Alternatively, the memory 1803 may include non-volatile memory such as ROM, flash memory, hard drive, or solid state drive. Alternatively, memory 1803 may include a combination of the above memory types.

An embodiment of the present invention further provides a computer storage medium, and the computer storage medium may be configured to store instructions of the computer software used by the core network device in the embodiment shown in FIG. 10, fig. 12 or FIG. 15. The computer software instruction includes a program that is for a core network device to carry out the above embodiment. The storage medium includes, but is not limited to, flash memory, a hard drive, and a solid state drive.

An embodiment of the present invention further provides a computer program product. When started by a computing device, the computer product may implement the communication method designed for the core network device in the embodiment of FIG. 10, fig. 12 or FIG. fifteen.

The terminal device in the embodiment shown in FIG. 16 may be implemented by terminal 1900 shown in FIG. 19. As shown in FIG. 19, where Fig. 19 is a block diagram of another terminal according to an embodiment of the present invention. Terminal 1900 shown in FIG. 19 includes a processor 1901 and a transceiver 1902. The transceiver 1902 is configured to support communication between the terminal device 1900 and the base station in the above embodiments. The processor 1901 is communicatively connected to the transceiver 1902, for example, connected to the transceiver 1902 using a bus. The tag device 1900 may further include a memory 1903. The memory 1903 is configured to store data and program code that is executed by the tag device 1900, and the processor 1901 is configured to execute application code stored in the memory 1903 to implement actions performed by the tag device. device provided in any embodiment shown in FIG. 4 or the embodiment shown in FIG. 6.

It should be noted that, in an actual implementation, a tag may include one or more processors, and the structure of the tag 1900 is not a limitation to this embodiment of the present invention.

Processor 1901 may be a CPU, NP, chip, or any combination thereof. The microcircuit may be an ASIC, a PLD, or a combination thereof. The PLD may be CPLD, FPGA, GAL, or any combination thereof.

Memory 1903 may include volatile memory such as RAM. Alternatively, the memory 1903 may include non-volatile memory such as ROM, flash memory, hard drive, or solid state drive. Alternatively, memory 1903 may include a combination of the above types of memory.

An embodiment of the present invention further provides a computer storage medium, and the computer storage medium may be configured to store instructions for computer software used by a terminal device in the embodiment shown in FIG. 16. The computer software instruction includes a program that is for a terminal device to execute the above embodiment. The storage medium includes, but is not limited to, flash memory, a hard drive, and a solid state drive.

An embodiment of the present invention further provides a computer program product. When started by a computing device, the computing product may perform the communication method designed for the terminal device in the embodiment of FIG. 16.

In the description, claims and accompanying drawings of the present invention, the terms "first", "second", "third", "fourth", etc. are intended to distinguish between different objects, but do not indicate a specific order. In addition, the terms "comprises", "including" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a sequence of steps or blocks is not limited to the listed steps or blocks, but, alternatively, further includes a step or block not listed, or further possibly includes into another integral step or unit of a process, method, product or device.

A person skilled in the art can understand that the sequence numbers of the above processes do not indicate the sequence of execution in various embodiments of the present invention. The execution sequences of the processes should be determined according to the functions and internal logic of the processes and should not be considered as any limitation on the processes for implementing the embodiments of the present invention.

All or some of the above embodiments may be implemented using software, hardware, firmware, or any combination thereof. When using software to implement the embodiments, the embodiments may be implemented in whole or in part in the form of a computer program product. A computer program product includes one or more computer instructions. When the instructions of a computer program are downloaded and executed on a computer, a procedure or functions according to embodiments of the present invention is generated in whole or in part. The computer may be a general purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer instructions may be stored on a computer-readable medium or may be transferred from a computer-readable medium to another computer-readable medium. For example, computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center over a wired network (such as coaxial cable, fiber, or digital subscriber line (DSL) ) or wireless (eg infrared, radio and microwave, etc.) method. A computer-readable storage medium can be any usable medium accessible to a computer, or a storage device such as a server or data center that combines one or more usable media. The medium used may be a magnetic medium (eg floppy disk, hard disk or magnetic tape), an optical medium (eg a DVD), a semiconductor medium (eg a solid state disk (SSD)) or the like.

One skilled in the art can understand that all or some of the processes of the methods in the embodiments may be implemented by a computer program instructing the appropriate hardware. The program may be stored on a computer-readable storage medium. When executing the program, the processes of the methods in the embodiments are performed. The above storage medium may include: a magnetic disk, an optical disk, read-only memory (ROM) or random access memory (RAM).

The above description is merely exemplary embodiments of the present invention and is, of course, not intended to limit the protection scope of the present invention. Therefore, equivalent changes made in accordance with the claims of the present invention should be within the scope of the present invention.

Claims (54)

1. A communication method, comprising the steps of: transmitting, by the target network access device, a route switch request to the core network device, the route switch request comprising a session ID accepted by the target network access device and a session ID rejected by the target network access device; and receiving, by means of the target network access device, a response message to the route switching request sent by the core network device, wherein the response message to the route switching request contains a session identifier for which the route switching was successfully completed. 2. The method of claim 1, wherein the route switch request message further comprises: reason information corresponding to the session rejected by the target network access device. 3. The method of claim 2, wherein the cause information is that: the target network access device does not support the network segment corresponding to the rejected session, or the resource is not available for the network segment supported by the target network access device and corresponding to the rejected session. 4. The method according to any one of paragraphs. 1-3, further comprising, before the step of transmitting, by the target network access device, a route switch request to the core network device, the steps of: receiving, with the target network access device, a handover request from the source network access device, wherein the handover request is used to request handover of the terminal device session from the source network access device to the target network access device; and the handover request contains a session ID of the requested handover and indication information of the network segment corresponding to the session; performing, with the target network access device, access control based on the network segment support state, the resource usage state, and the handover request; transmitting, with the target network access device, a handover response message to the source network access device; receiving, with the target network access device, a handover confirmation message from the terminal device. 5. The method of claim 4, wherein the network segment indication information is S-NSSAI single network segment selection assistance information. 6. The method of claim 4, wherein the handover response message is a handover request acknowledgment message, wherein the handover request acknowledgment message contains a rejected quality of service (QoS) flow identifier. 7. The method of claim 6, wherein the handover request acknowledgment message further comprises information used to indicate a reason for rejecting the at least one QoS flow. 8. The method of claim 7, wherein the information used to indicate the reason for rejecting the QoS flow includes one of: a multiple data flow identifier, an unavailable resource, or an invalid QoS combination corresponding to the QoS flows. 9. A communication method, comprising the steps of: receiving, by the core network device, a route switch request from a target network access device, wherein the route switch request comprises a session ID accepted by the target network access device and a session ID rejected by the target network access device; and transmitting, by means of the core network device, a route switch request response message to a target network access device, the route switch request response message containing a session identifier for which the route switch was successfully completed. 10. The method of claim 9, wherein the route switch request message further comprises reason information corresponding to the session denied by the target network access device. 11. The method of claim 9 or 10, wherein the reason information is that: the target network access device does not support the network segment corresponding to the rejected session; or the resource is not available for the network segment supported by the target network access device and corresponding to the rejected session. 12. The method according to any one of paragraphs. 9-11, further comprising the step of performing, by means of the core network device, switching the route of the received session and deactivating or releasing the rejected session. 13. The method of claim 12, wherein the step of performing, with the core network device, switching the route of the received session and deactivating or releasing the rejected session, comprises the sub-step of: performing, with the core network device, releasing the rejected session because the target network access device does not support the network segment corresponding to the rejected session. 14. Communication device, characterized in that it is a core network device containing a processor and a transceiver; wherein the transceiver is configured to receive a route switch request from a target network access device, wherein the route switch request comprises a session ID accepted by the target network access device and a session ID rejected by the target network access device; and the transceiver is configured to send a route switch request response message to a target network access device, wherein the route switch request response message contains a session identifier for which the route switch was successfully completed. 15. The communications device of claim 14, wherein the route switch request message further comprises reason information corresponding to the session denied by the target network access device. 16. The communication device according to claim 15, in which the cause information is that: the target base station does not support the network segment corresponding to the rejected session; or the resource is not available for the network segment supported by the target network access device and corresponding to the rejected session. 17. The communications device of claim 14 or 15, wherein the processor is configured to switch the route of the received session and deactivate or release the rejected session. 18. The communications device of claim 17, wherein the processor is further configured to release the rejected session because the target network access device does not support the network segment corresponding to the rejected session. 19. A communication device, characterized in that it is a target network access device containing a processor and a transceiver; and the transceiver is configured to transmit a route switch request to the core network device, wherein the route switch request comprises a session ID accepted by the target network access device and a session ID rejected by the target network access device; and the transceiver is configured to receive a route switch request response message transmitted by the core network device, wherein the route switch request response message contains a session identifier for which the route switch is successfully completed. 20. The communications device of claim 19, wherein the route switch request response message further comprises: reason information corresponding to the session rejected by the target network access device. 21. The communication device according to claim 20, wherein the cause information is that: the target network access device does not support the network segment corresponding to the rejected session; or the resource is not available for the network segment supported by the target network access device and corresponding to the rejected session. 22. Communication device according to any one of paragraphs. 19-21, in which the transceiver is further configured to receive a handover request from the source network access device, wherein the handover request is used to request handover of the terminal device session from the source network access device to the target network access device; and the handover request contains a session ID of the requested handover and indication information of the network segment corresponding to the session; a the processor is configured to perform admission control based on the network segment support state, the resource usage state, and the handover request; wherein the transceiver is further configured to transmit a handover response message to the source network access device and receive a handover confirmation message from the terminal device. 23. The communication apparatus of claim 22, wherein the network segment designation information is individual network segment selection assistance information (S-NSSAI). 24. The communications apparatus of claim 22, wherein the handover response message is a handover request acknowledgment message, wherein the handover request acknowledgment message contains a rejected quality of service (QoS) flow identifier. 25. The communications apparatus of claim 24, wherein the handover request acknowledgment message further comprises information used to indicate a reason for rejecting the at least one QoS flow. 26. The communication apparatus of claim 25, wherein the information used to indicate the reason for rejecting the QoS flow comprises one of: a duplicated QoS flow set identifier, an unavailable resource, or an invalid QoS combination corresponding to the QoS flows. 27. A computer-readable storage medium that stores instructions that cause, when executed by a computer, the execution of the method according to any one of paragraphs. 1-8 or 9-13. 28. A communication system containing a target network access device and a core network device; and the target network access device is configured to send a route switch request to the core network device, wherein the route switch request comprises a session ID accepted by the target network access device and a session ID rejected by the target network access device; a the core network device is configured to send a response message to the route switch request to the target network access device, wherein the response message to the route switch request contains a session identifier for which the route switch is successfully completed.

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