Method and apparatus for roaming between communication systems

Abstract

To provide a method and a device for moving between communication systems, for moving user equipment from a first communication system to a second communication system.SOLUTION: Embodiments of the present application relate to the field of communication technology. A method includes: a step of UE receiving a first message, in which the first message is used to set or modify a first EPS bearer for the UE in a first communication system and the first message includes first quality of service QoS flow information that is of a second communication system and corresponds to the first EPS bearer; a step of the UE saving the first QoS flow information; a step of the UE moving from the first communication system to the second communication system; and a step of the UE determining QoS flow information to be used by the UE in the second communication system based on a first condition, in which the first condition includes the first QoS flow information.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This application claims priority to PCT Patent Application No. PCT / CN2017 / 083522, entitled "METHOD FOR MOVING BETWEEN COMMUNICATIONS SYSTEMS AND APPARATUS," filed with the China Patent Office on May 8, 2017, which is incorporated herein by reference in its entirety.

[0002] TECHNICAL FIELD This application relates to the field of communications technology, and more particularly to methods and apparatus for navigating between communications systems. [Background technology]

[0003] With the rapid development of communication technology, various user equipment (UE) such as smartphones, tablet computers, and handheld devices have emerged. These UEs can support different generations of mobile communication networks and can be handed over between different generations of mobile communication networks. Fifth-generation (5G) mobile communication technology is an extension of fourth-generation (4G) mobile communication technology and is characterized by high performance, low latency, and large capacity. The maximum data transmission speed of fifth-generation mobile communication technology can reach several tens of Gbps, which is 1,000 times faster than the data transmission speed of existing fourth-generation (4G) networks. Therefore, if a UE is in a 4G network and supports a 5G network, the UE can be handed over from the 4G network to the 5G network to achieve a higher data transmission speed.

[0004] In the prior art, a UE can move from a 4G network to a 3G network because the UE's EPS bearers in the 4G network have a one-to-one mapping relationship with the PDP contexts in the 3G network, and the QoS parameters of the 4G network also have a one-to-one mapping relationship with the QoS parameters of the 3G network. Therefore, the UE can move directly from the 4G network to the 3G network. This movement described herein includes two cases: when the UE is in an idle state, the UE reselects a 3G network; and when the UE is in a connected state, the UE is handed over to the 3G network. Specifically, when the UE is in an idle state, the UE may send a Non-Access Stratum (NAS) Route Area Update (RAU) signaling to the SGSN, so that the UE locally maps the QoS context to the PGW and also maps the EPS bearer context to the PDP context. When the UE is in a connected state, after the UE receives a handover command from a 4G base station, the UE locally maps the QoS context.

[0005] However, since the EPS bearers in the 4G network are replaced with QoS flows in the 5G network, and the QoS flows do not have a one-to-one mapping relationship with the EPS bearers, and the QoS parameters do not have a one-to-one mapping relationship with each other, the UE cannot move from the 4G network to the 5G network by using the method used by the UE to move from the 4G network to the 3G network. Summary of the Invention [Means for solving the problem]

[0006] The embodiments of the present application provide a method and apparatus for moving between communication systems, for moving a UE from a first communication system to a second communication system.

[0007] To achieve the above objectives, the following technical solutions are used in the embodiments of the present application.

[0008] According to a first aspect, there is provided a method for moving between communication systems, which is used to move a user equipment (UE) from a first communication system to a second communication system, the method including the steps of: receiving, by the UE, a first message, the first message being used to establish or modify a first EPS bearer for the UE in the first communication system, the first message including first Quality of Service (QoS) flow information of the second communication system and corresponding to the first EPS bearer; storing, by the UE, the first QoS flow information; moving from the first communication system to the second communication system, for example, moving the UE from a 4G communication system to a 5G communication system; and determining, by the UE, QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the first QoS flow information. In the above technical solution, the UE may store the first QoS flow information in advance, and directly use the stored first QoS flow information after moving from the first communication system to the second communication system, so that the UE is moved to the second communication system and has corresponding QoS context information in the second communication system, and the service can be performed normally without interruption.

[0009]

[0013] Referring to the first aspect, in a first possible implementation form of the first aspect, before the step of the UE receiving the first message, the method further includes a step of the UE sending first information to a first core network entity in a process of establishing a PDN connection in the first communication system, the first information being used by the first core network entity to determine that the PDN connection is movable from the first communication system to a second communication system. In the above possible technical solution, the UE may enable the first core network entity to determine that the PDN connection is movable to the second communication system by using the first information, and the first core network entity to send first QoS flow information to the UE.

[0010] Referring to a first possible implementation form of the first aspect, in a second possible implementation form of the first aspect, the first information includes information used to indicate that the PDN connection is movable to a second communication system, or the first information includes information used to indicate that a service and session continuity (SSC) mode of a PDU session corresponding to the PDN connection in the second communication system is a specified mode.

[0011] Referring to the first aspect, in a third possible implementation form of the first aspect, before the step of the UE receiving the first message, the method further includes a step of the UE transmitting second information to a first core network entity in a process of establishing a PDN connection in the first communication system, where the second information is used to indicate an SSC mode of a PDU session corresponding to the PDN connection in the second communication system.

[0012] With reference to any one of the first aspect to the third possible implementation forms of the first aspect, in a fourth possible implementation form of the first aspect, the first quality of service QoS flow information includes one or more QoS rules.

[0013] Referring to any one of the first aspect to the fourth possible implementation forms of the first aspect, in a fifth possible implementation form of the first aspect, the first EPS bearer is a default bearer, and the first quality of service QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0014] With reference to any one of the first aspect to the fifth possible implementation forms of the first aspect, in a sixth possible implementation form of the first aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0015] Referring to the first aspect, in a seventh possible implementation form of the first aspect, the method further includes a step of the UE acquiring a first QoS flow identifier, wherein the first QoS flow identifier is acquired after the UE adds a specific value to the first EPS bearer identifier, or the first QoS flow identifier is acquired after the UE adds a specific field to the first EPS bearer identifier.

[0016] Referring to any one of the seventh possible implementation forms of the first aspect to the seventh possible implementation form of the first aspect, in an eighth possible implementation form of the first aspect, the step of the UE storing the first QoS flow information includes: the UE storing a correspondence relationship between a bearer identifier of the first EPS bearer and the first QoS flow information, or the UE storing a correspondence relationship between the first EPS bearer context and the first QoS flow information, or the UE storing a correspondence relationship between the first EPS bearer context and index information of the first QoS flow, wherein the index information includes the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier.

[0017] Referring to any one of the first aspect to the eighth possible implementation forms of the first aspect, in a ninth possible implementation form of the first aspect, the step of a UE moving from a first communication system to a second communication system includes: the UE transmitting first EPS bearer status information to a second core network entity, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE, the first EPS bearer status information being used to identify active EPS bearers belonging to the UE and having corresponding QoS flow information; and the UE receiving a second message transmitted by the second core network entity, the second message including second EPS bearer status information, the second EPS bearer status information being used to identify active EPS bearers belonging to the UE and having corresponding QoS flow information and determined by the second core network entity, and in response, the first condition further including the second EPS bearer status information. In the above possible technical solution, the UE reports the first EPS bearer status information so as to ensure that the consistency between the QoS flow status or QoS flow quantity recorded by the UE and the network is maintained after the UE moves to the second communication system.

[0018] Referring to any one of the eighth possible implementation forms of the first aspect, in a tenth possible implementation form of the first aspect, the step of the UE moving from a first communication system to a second communication system includes: the UE transmitting first QoS flow status information to a second core network entity, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE, the first QoS flow status information being used to identify QoS flows corresponding to active EPS bearers of the UE; and the UE receiving a second message transmitted by the second core network entity, the second message including second QoS flow status information, the second QoS flow status information being used to identify QoS flows corresponding to active EPS bearers of the UE and determined by the second core network entity; and accordingly, the first condition further includes the second QoS flow status information. In the above possible technical solution, the UE reports the first QoS flow status information, so as to ensure that the consistency between the QoS flow status or QoS flow amount recorded by the UE and the network is maintained after the UE moves to the second communication system.

[0019]

[0023] Referring to any one of the tenth possible implementation forms of the first aspect, in an eleventh possible implementation form of the first aspect, the step of the UE moving from the first communication system to the second communication system includes: the UE receiving a handover command sent by a base station in the first communication system, the handover command including a session identifier and a QoS flow identifier, and in response, the first condition further including the session identifier and the QoS flow identifier. In the above possible technical solution, the UE receives the session identifier and the QoS flow identifier to ensure that consistency between the QoS flow status or the QoS flow amount recorded by the UE and the network is maintained.

[0020]

[0023] Referring to any one of the eleventh possible implementation forms of the first aspect, in a twelfth possible implementation form of the first aspect, after the UE receives the first message and before the UE moves from the first communication system to the second communication system, the method further includes: the UE receiving a fourth message, the fourth message being used to delete the first EPS bearer; and the UE deleting the first EPS bearer and the first QoS flow information corresponding to the first EPS bearer. In the above possible technical solution, the UE deletes the first QoS flow information corresponding to the first EPS bearer to ensure consistency between the QoS flow status or QoS flow amount recorded by the UE and the network.

[0021] With reference to any one of the 1st aspect to 12th possible implementation forms of the 1st aspect, in a 13th possible implementation form of the 1st aspect, the first QoS flow information is included in a protocol configuration option PCO. In the above-mentioned possible technical solution, the UE receives the first QoS flow information carried in the PCO so as to ensure that changes to the current first communication system are minimized.

[0022] With reference to the first or second possible implementation manner of the first aspect, in a fourteenth possible implementation manner of the first aspect, the first information is included in a protocol configuration option PCO. In the above-mentioned possible technical solution, the UE transmits the first QoS flow information carried by using the PCO, so as to ensure that changes to the current first communication system are minimized.

[0023] Referring to the third possible implementation manner of the first aspect, in a fifteenth possible implementation manner of the first aspect, the second information is included in a protocol configuration option PCO.

[0024] Referring to any one of the 15th possible implementation forms of the first aspect, in a 16th possible implementation form of the first aspect, the step of the UE storing the first QoS flow information includes the UE storing the first QoS flow information in a first EPS bearer context, or the UE storing index information of the first QoS flow information in context information of the first EPS bearer, wherein the index information includes the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier.

[0025] Referring to any one of the 1st aspect to 16th possible implementation forms of the 1st aspect, in a 17th possible implementation form of the 1st aspect, after the UE determines QoS flow information to be used by the UE in the second communication system based on the first condition, the method further includes a step of the UE deleting a second EPS bearer context, wherein the second EPS bearer is an EPS bearer related to the UE and does not have corresponding QoS flow information.

[0026] Referring to any one of the 17th possible implementation forms of the first aspect, in an 18th possible implementation form of the first aspect, the step of the UE moving from the first communication system to the second communication system includes the steps of the UE receiving a handover command, the handover command including index information of one or more QoS flows, the index information including a QoS flow identifier or a combination of a QoS flow identifier and a PDU session identifier, and the UE moving from the first communication system to the second communication system based on the handover command.

[0027] Referring to an 18th possible implementation form of the first aspect, in a 19th possible implementation form of the first aspect, the step of the UE determining QoS flow information to be used by the UE in the second communication system based on the first condition includes the UE associating a currently used EPS bearer with index information that belongs to the QoS flow and is included in the handover command, and the UE deleting an EPS bearer that is in the currently used EPS bearer and is not associated with the index information of the QoS flow.

[0028] Referring to a 19th possible implementation form of the first aspect, in a 20th possible implementation form of the first aspect, the UE associating the currently used EPS bearer with index information that belongs to the QoS flow and is included in the handover command includes the UE obtaining an EPS bearer context corresponding to the index information of the QoS flow, or the UE obtaining an EPS bearer identifier corresponding to the index information of the QoS flow.

[0029] Referring to any one of the twentieth possible implementation forms of the first aspect to the first aspect, in a twenty-first possible implementation form of the first aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0030] According to a second aspect, there is provided a method for moving between communication systems, which is used to move a user equipment (UE) from a first communication system to a second communication system, the method including: a first core network entity determining first quality of service (QoS) flow information that is of the second communication system and corresponds to a first EPS bearer of the UE in the first communication system; a first core network entity transmitting a first message, the first message being used to set up or modify the first EPS bearer for the UE in the first communication system, the first message including the first QoS flow information; a first core network entity storing the first QoS flow information; and, when the UE moves from the first communication system to the second communication system, the first core network entity determining QoS flow information to be used by the UE in the second communication system based on a fourth condition, the fourth condition including the first QoS flow information.

[0031] Referring to the second aspect, in a first possible implementation form of the second aspect, before the first core network entity determines first QoS flow information that belongs to the second communication system and corresponds to a first EPS bearer of the UE in the first communication system, the method further includes a step in which the first core network entity receives first information sent by the UE in a process of establishing a PDN connection in the first communication system, and a step in which the first core network entity determines, based on the first information, that the PDN connection is movable from the first communication system to the second communication system.

[0032] Referring to a first possible implementation form of the second aspect, in a second possible implementation form of the second aspect, the first information includes information used to indicate that the PDN connection is movable to a second communication system, or the first information includes information used to indicate that a service and session continuity (SSC) mode of a PDU session corresponding to the PDN connection in the second communication system is a specified mode.

[0033] Referring to the second aspect, in a third possible implementation form of the second aspect, before the step of the first core network entity sending the first message, the method further includes a step of receiving, by the first core network entity, second information sent by the UE in the process of establishing a PDN connection in the first communication system, where the second information is used to indicate an SSC mode of a PDU session corresponding to the PDN connection in the second communication system.

[0034] With reference to any one of the second aspect to the third possible implementation forms of the second aspect, in a fourth possible implementation form of the second aspect, the first quality of service QoS flow information includes one or more QoS rules.

[0035] Referring to any one of the second aspect to the fourth possible implementation forms of the second aspect, in a fifth possible implementation form of the second aspect, the first EPS bearer is a default bearer, and the first quality of service QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0036] With reference to the fourth or fifth possible implementation form of the second aspect, in a sixth possible implementation form of the second aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0037] Referring to the second aspect, in a seventh possible implementation form of the second aspect, the method further includes a step in which the first core network entity acquires a first QoS flow identifier, wherein the first QoS flow identifier is acquired after the UE adds a specific value to the first EPS bearer identifier, or the first QoS flow identifier is acquired after the UE adds a specific field to the first EPS bearer identifier.

[0038] Referring to any one of the seventh possible implementation forms of the second aspect to the seventh possible implementation form of the second aspect, in an eighth possible implementation form of the second aspect, the step of the first core network entity determining first QoS flow information that belongs to the second communication system and corresponds to a first EPS bearer of a UE in the first communication system includes: when the first message is used to set up a first EPS bearer for the UE in the first communication system, the first core network entity mapping the first EPS bearer context to the first QoS flow information of the second communication system; or when the first message is used to modify a first EPS bearer for the UE in the first communication system, the first core network entity mapping the context of the modified first EPS bearer to the first QoS flow information of the second communication system.

[0039] Referring to an eighth possible implementation form of the second aspect, in a ninth possible implementation form of the second aspect, the first message is used to set up a first EPS bearer for a UE in a first communication system, and the method further includes a step of the first core network entity allocating a QoS flow identifier to the UE, or a step of mapping a bearer identifier of the first EPS bearer to the QoS flow identifier.

[0040] Referring to an eighth possible implementation form of the second aspect, in a tenth possible implementation form of the second aspect, the first message is used to modify a first EPS bearer for a UE in a first communication system, and the method further includes a step in which the first core network entity determines that the first EPS bearer has corresponding first QoS flow information of the second communication system.

[0041] With reference to a tenth possible implementation form of the second aspect to a tenth possible implementation form of the second aspect, in an eleventh possible implementation form of the second aspect, the step of the first core network entity storing the first QoS flow information includes the first core network entity storing a correspondence relationship between a bearer identifier of the first EPS bearer and the first QoS flow information, or the first core network entity storing a correspondence relationship between the first EPS bearer context and the first QoS flow information, or the first core network entity storing a correspondence relationship between the first EPS bearer context and the first QoS flow information. the UE storing a correspondence relationship between the first EPS bearer and index information of the first QoS flow, wherein the index information includes a first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier; or the UE storing a correspondence relationship between the first EPS bearer and the first QoS flow, or the UE storing a correspondence relationship between the first EPS bearer and index information of the first QoS flow, wherein the index information includes the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier.

[0042] Referring to an eleventh possible implementation form of the second aspect, in a twelfth possible implementation form of the second aspect, the method further includes a step of receiving, by a first core network entity, second information sent by a second core network entity, where the second information includes a linked bearer identifier and a bearer identifier movable to the second communication system or includes a PDN connection context, where the PDN connection context includes an EPS bearer context movable to the second communication system, and the second core network entity is a core network entity in the second communication system and responsible for access and mobility management of the UE; and a step of generating, by the first core network entity, second QoS flow information for the second communication system based on a fifth condition, where the second QoS flow information includes QoS flow information corresponding to an active EPS bearer of the UE and determined by the second core network entity, and the fifth condition includes the second information and a correspondence relationship.

[0043] Referring to a twelfth possible implementation form of the second aspect, in a thirteenth possible implementation form of the second aspect, the method further includes a step of receiving, by a first core network entity, a PDN connection context and first QoS flow status information sent by a second core network entity, where the first QoS flow status information is used to identify QoS flows corresponding to active EPS bearers of the UE; and a step of generating, by the first core network entity, second QoS flow information for the second communication system based on a fifth condition, where the second QoS flow information includes QoS flows corresponding to active EPS bearers of the UE and determined by the second core network entity, and the fifth condition includes the first QoS flow information and a correspondence relationship.

[0044] Referring to any one of the second aspect to the thirteenth possible implementation form of the second aspect, in a fourteenth possible implementation form of the second aspect, the first QoS flow information is included in a protocol configuration option PCO.

[0045] Referring to the first or second possible implementation manner of the second aspect, in a fifteenth possible implementation manner of the second aspect, the first information is included in a protocol configuration option PCO.

[0046] Referring to the third possible implementation manner of the second aspect, in a sixteenth possible implementation manner of the second aspect, the second information is included in a protocol configuration option PCO.

[0047] Referring to any one of the 16th possible implementation forms of the second aspect to the 2nd aspect, in a 17th possible implementation form of the second aspect, the first communication system is a 4th generation communication system, the second communication system is a 5th generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF + PGW-C).

[0048] According to a third aspect, there is provided a method for moving between communication systems, which is used to move a user equipment (UE) from a first communication system to a second communication system, the method comprising the steps of: when the UE moves from the first communication system to the second communication system, a second core network entity acquiring first status information and a PDN connection context, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE; and determining, by the second core network entity, second information based on a sixth condition, the second information being used by the first core network entity to determine QoS flow information to be used by the UE in the second communication system, the sixth condition being related to the first status information and the PDN connection context. a determining step, wherein the second core network entity transmits the second information to the first core network entity and receives the third information transmitted by the first core network entity; a generating step, wherein the second core network entity generates second status information based on a seventh condition, the seventh condition including the third information; and a transmitting step, wherein the second core network entity transmits a second message to the UE, the second message including the second status information, the second status information being used by the UE to determine QoS flow information to be used in the second communication system.

[0049] Referring to the third aspect, in a first possible implementation form of the third aspect, the first status information is first EPS bearer status information, the second status information is second EPS bearer status information, the first EPS bearer status information is used to identify an active EPS bearer that belongs to the UE and has corresponding QoS flow information, and the second EPS bearer status information is used to identify an active EPS bearer that belongs to the UE and has corresponding QoS flow information and is determined by a second core network entity.

[0050] Referring to the third aspect, in a second possible implementation form of the third aspect, the first status information is first QoS flow status information, the second status information is second QoS flow status information, the first QoS flow status information is used to identify a QoS flow corresponding to an active EPS bearer of the UE, and the second QoS flow status information is used to identify a QoS flow corresponding to an active EPS bearer of the UE and determined by a second core network entity.

[0051] Referring to a first possible implementation form of the third aspect, in a third possible implementation form of the third aspect, the third information includes a bearer identifier of an active EPS bearer belonging to the UE and determined by the first core network entity, or the third information includes second QoS flow status information determined by the first core network entity.

[0052] Referring to the first possible implementation form of the third aspect, in a fourth possible implementation form of the third aspect, the step of the second core network entity determining the second information based on the first status information and the PDN connection context includes: the second core network entity determining the second information based on an EPS bearer intersection set between the first EPS bearer status information and the PDN connection context, wherein the second information includes a linked bearer identifier and a bearer identifier movable to the second communication system or includes a PDN connection context, and the PDN connection context includes an EPS bearer context movable to the second communication system.

[0053] Referring to a second possible implementation form of the third aspect, in a fifth possible implementation form of the third aspect, the step of the second core network entity determining the second information based on the first status information and the PDN connection context includes: the second core network entity mapping the PDN connection context to QoS flow information of the second communication system; and determining the second information based on a QoS flow intersection set between the mapped QoS flow information and the first QoS flow status information, wherein the second information includes the second QoS flow status information.

[0054] With reference to any one of the third aspect to the fifth possible implementation forms of the third aspect, in a sixth possible implementation form of the third aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0055] According to a fourth aspect, there is provided a method for moving between communication systems, which is used to move a user equipment (UE) from a first communication system to a second communication system, the method including: a UE establishing a first EPS bearer in the first communication system; a UE moving from the first communication system to the second communication system; a UE receiving a first message, the first message including first Quality of Service (QoS) flow information of the second communication system and corresponding to the first EPS bearer; and a UE determining QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the first QoS flow information.

[0056] Referring to the fourth aspect, in a first possible implementation form of the fourth aspect, the first quality of service QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0057] Referring to a first possible implementation form of the fourth aspect, in a second possible implementation form of the fourth aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0058] Referring to the fourth aspect, in a third possible implementation form of the fourth aspect, the method further includes a step of the UE acquiring a first QoS flow identifier, wherein the first QoS flow identifier is acquired after the UE adds a specific value to the first EPS bearer identifier, or the first QoS flow identifier is acquired after the UE adds a specific field to the first EPS bearer identifier.

[0059] Referring to any one of the fourth aspect to the third possible implementation forms of the fourth aspect, in a fourth possible implementation form of the fourth aspect, the step of the UE moving from the first communication system to the second communication system includes the UE sending first EPS bearer status information to a second core network entity, where the first EPS bearer status information is used to identify active EPS bearers of the UE, and the second core network entity is a core network entity in the second communication system and responsible for access and mobility management of the UE.

[0060] Referring to any one of the fourth aspect to the third possible implementation forms of the fourth aspect, in a fifth possible implementation form of the fourth aspect, the step of the UE moving from the first communication system to the second communication system includes the UE transmitting first QoS flow status information to a second core network entity, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE, the first QoS flow status information being used to identify QoS flows corresponding to active EPS bearers of the UE.

[0061] Referring to the fourth aspect, in a sixth possible implementation form of the fourth aspect, the first message is a registration accept message and the N1 session management information parameter of the registration accept message includes the first QoS flow information, or the first message is a PDU session modification message and the N1 session management information parameter of the PDU session modification message includes the first QoS flow information.

[0062] Referring to the fourth aspect, in a seventh possible implementation manner of the fourth aspect, the first message is a handover command message, and the handover command message includes the first QoS flow information.

[0063] With reference to a seventh possible implementation manner of the fourth aspect, in an eighth possible implementation manner of the fourth aspect, the target to source transparent container of the handover command message includes the first QoS flow information.

[0064] Referring to an eighth possible implementation form of the fourth aspect, in a ninth possible implementation form of the fourth aspect, an access stratum of the UE obtains first QoS flow information from a target to source transparent container and sends the first QoS flow information to a non-access stratum of the UE.

[0065] Referring to any one of the fourth to ninth possible implementation forms of the fourth aspect, in a tenth possible implementation form of the fourth aspect, the first message further includes information about a first EPS bearer corresponding to the first QoS flow information.

[0066] With reference to a tenth possible implementation form of the fourth aspect, in an eleventh possible implementation form of the fourth aspect, the information about the first EPS bearer includes a bearer identifier of the first EPS bearer.

[0067] Referring to the tenth or eleventh possible implementation form of the fourth aspect, in a twelfth possible implementation form of the fourth aspect, after the step of the UE determining QoS flow information to be used by the UE in the second communication system based on the first condition, the method further includes a step of the UE deleting a second EPS bearer context, wherein the second EPS bearer is an EPS bearer belonging to the UE and not included in the first message, or the second EPS bearer is an EPS bearer belonging to the UE and does not have corresponding QoS flow information.

[0068] With reference to any one of the twelfth possible implementation forms of the fourth aspect to the fourth aspect, in a thirteenth possible implementation form of the fourth aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF + PGW-C).

[0069] According to a fifth aspect, there is provided a method for moving between communication systems, which is used to move a user equipment (UE) from a first communication system to a second communication system, the method including: when the UE moves from the first communication system to the second communication system, a first core network entity receiving first information sent by a second core network entity, the first information including a PDN connection context, the PDN connection context including an EPS bearer context movable to the second communication system, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE; and determining, by the first core network entity, QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the PDN connection context.

[0070] Alternatively, the method includes the steps of: when the UE moves from the first communication system to the second communication system, a first core network entity receiving second information sent by a second core network entity, the second information including a PDN connection movable to the second communication system and QoS flow status information corresponding to the PDN, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE; and determining, by the first core network entity, QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the PDN connection and the QoS flow status information. Further, the PDN connections include all PDN connections of the UE in the first communication system, and the method further includes the step of the first core network entity removing QoS flows that are in QoS flows corresponding to EPS bearers of the PDN connections but are not in the QoS flow status information.

[0071] Referring to the fifth aspect, in a first possible implementation form of the fifth aspect, the QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0072] Referring to the first possible implementation form of the fifth aspect, in a second possible implementation form of the fifth aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0073] Referring to any one of the fifth aspect to the second possible implementation forms of the fifth aspect, in a third possible implementation form of the fifth aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0074] According to a sixth aspect, there is provided a method for moving between communication systems, which is used to move a user equipment (UE) from a first communication system to a second communication system, the method including: when the UE moves from the first communication system to the second communication system, a second core network entity receiving first Quality of Service (QoS) flow information of the second communication system corresponding to a first EPS bearer established by the UE in the first communication system; and the second core network entity sending a first message to the UE, the first QoS flow information being included in the first QoS flow information.

[0075] Referring to the sixth aspect, in a first possible implementation form of the sixth aspect, the first QoS flow information includes one or more of the following information: a session aggregate maximum bit rate, an SSC mode, a PDU session identifier, and a QoS rule.

[0076] Referring to a first possible implementation form of the sixth aspect, in a second possible implementation form of the sixth aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0077] Referring to any one of the sixth aspect to the second possible implementation forms of the sixth aspect, in a third possible implementation form of the sixth aspect, the method further includes: a step of a second core network entity acquiring first EPS bearer status information and a PDN connection context, where the first EPS bearer status information is used to identify active EPS bearers of the UE; and a step of a second core network entity determining third information based on the first EPS bearer status information and the PDN connection context, where the third information includes a PDN connection and an EPS bearer on the PDN connection that can be moved to the second communication system, or a PDN connection context that can be moved to the second communication system.

[0078] Referring to any one of the sixth aspect to the second possible implementation forms of the sixth aspect, in a fourth possible implementation form of the sixth aspect, the method further includes: a step of acquiring, by a second core network entity, first QoS flow status information and a PDN connection context, wherein the first QoS flow status information is used to identify a QoS flow corresponding to an active EPS bearer of the UE; a step of transmitting, by the second core network entity, the first QoS flow status information and the PDN connection context to the first core network entity; and a step of receiving, by the first core network entity, second QoS flow information transmitted by the first core network entity, wherein the second QoS flow information is used to identify a QoS flow corresponding to an active EPS bearer of the UE and determined by the first core network entity.

[0079] Referring to the sixth aspect, in a fifth possible implementation form of the sixth aspect, the first message is a registration accept message, and the N1 session management information parameter of the registration accept message includes the first QoS flow information, or the first message is a PDU session modification message, and the N1 session management information parameter of the PDU session modification message includes the first QoS flow information.

[0080] Referring to the sixth aspect, in a sixth possible implementation form of the sixth aspect, the first message is a handover command message, and the handover command message includes first QoS flow information.

[0081] Referring to a sixth possible implementation form of the sixth aspect, in a seventh possible implementation form of the sixth aspect, the target to source transparent container of the handover command message includes the first QoS flow information.

[0082] Referring to any one of the sixth aspect to the seventh possible implementation forms of the sixth aspect, in an eighth possible implementation form of the sixth aspect, the first message further includes information about a first EPS bearer corresponding to the first QoS flow information.

[0083] Referring to an eighth possible implementation form of the sixth aspect, in a ninth possible implementation form of the sixth aspect, the information about the first EPS bearer includes a bearer identifier of the first EPS bearer.

[0084] Referring to any one of the sixth to ninth possible implementation forms of the sixth aspect, in a tenth possible implementation form of the sixth aspect, the first communication system is a fourth generation communication system and the second communication system is a fifth generation communication system.

[0085] According to a seventh aspect, there is provided a user equipment (UE), configured to move the UE from a first communication system to a second communication system, comprising: a receiving unit configured to receive a first message, the first message being used to establish or modify a first EPS bearer for the UE in the first communication system, the first message including first Quality of Service (QoS) flow information of the second communication system and corresponding to the first EPS bearer; a storing unit configured to store the first QoS flow information; a mobile unit configured to move from the first communication system to the second communication system; and a determining unit configured to determine QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the first QoS flow information.

[0086] Referring to the seventh aspect, in a first possible implementation form of the seventh aspect, before the step of receiving the first message, the UE further includes a transmitting unit configured to transmit first information to a first core network entity in a process of establishing a PDN connection in the first communication system, where the first information is used by the first core network entity to determine that the PDN connection is movable from the first communication system to a second communication system.

[0087] Referring to a first possible implementation form of the seventh aspect, in a second possible implementation form of the seventh aspect, the first information includes information used to indicate that the PDN connection is movable to a second communication system, or the first information includes information used to indicate that a service and session continuity (SSC) mode of a PDU session corresponding to the PDN connection in the second communication system is a specified mode.

[0088] Referring to the seventh aspect, in a third possible implementation form of the seventh aspect, the UE further comprises a transmitting unit configured to transmit second information to a first core network entity in a process of establishing a PDN connection in a first communication system, wherein the second information is used to indicate an SSC mode of a PDU session corresponding to the PDN connection in the second communication system.

[0089] With reference to any one of the seventh aspect to the third possible implementation forms of the seventh aspect, in a fourth possible implementation form of the seventh aspect, the first quality of service QoS flow information includes one or more QoS rules.

[0090] Referring to any one of the seventh aspect to the fourth possible implementation forms of the seventh aspect, in a fifth possible implementation form of the seventh aspect, the first EPS bearer is a default bearer, and the first quality of service QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0091] With reference to any one of the seventh aspect to the fifth possible implementation forms of the seventh aspect, in a sixth possible implementation form of the seventh aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0092] Referring to the seventh aspect, in a seventh possible implementation form of the seventh aspect, the determination unit is further configured to obtain a first QoS flow identifier, and the first QoS flow identifier is obtained after the UE adds a specific value to the first EPS bearer identifier, or the first QoS flow identifier is obtained after the UE adds a specific field to the first EPS bearer identifier.

[0093] With reference to any one of the seventh aspect to the seventh possible implementation forms of the seventh aspect, in an eighth possible implementation form of the seventh aspect, the storage unit stores a correspondence between a bearer identifier of a first EPS bearer and first QoS flow information, or stores a correspondence between a first EPS bearer context and the first QoS flow information, or stores a correspondence between the first EPS bearer and index information of the first QoS flow, and the index information is specifically configured to include the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier.

[0094] With reference to any one of the seventh to eighth possible implementation forms of the seventh aspect, in a ninth possible implementation form of the seventh aspect, the transmitting unit is further configured to transmit first EPS bearer status information to a second core network entity, the second core network entity being a core network entity in a second communication system and responsible for access and mobility management of the UE, the first EPS bearer status information being used to identify active EPS bearers belonging to the UE and having corresponding QoS flow information, the receiving unit is further configured to receive a second message transmitted by the second core network entity, the second message including second EPS bearer status information, the second EPS bearer status information being used to identify active EPS bearers belonging to the UE and having corresponding QoS flow information and determined by the second core network entity, and accordingly the first condition further includes the second EPS bearer status information.

[0095] With reference to any one of the seventh to eighth possible implementation forms of the seventh aspect, in a tenth possible implementation form of the seventh aspect, the transmitting unit is further configured to transmit first QoS flow status information to a second core network entity, the second core network entity being a core network entity in a second communication system and responsible for access and mobility management of the UE, the first QoS flow status information being used to identify a QoS flow corresponding to an active EPS bearer of the UE, the receiving unit is further configured to receive a second message transmitted by the second core network entity, the second message including the second QoS flow status information, the second QoS flow status information being used to identify a QoS flow corresponding to an active EPS bearer of the UE and determined by the second core network entity, and accordingly the first condition further includes the second QoS flow status information.

[0096] Referring to any one of the seventh to tenth possible implementation forms of the seventh aspect, in an eleventh possible implementation form of the seventh aspect, the receiving unit is further configured to receive a handover command sent by a base station in the first communication system, the handover command including a session identifier and a QoS flow identifier, and accordingly, the first condition further includes the session identifier and the QoS flow identifier.

[0097] Referring to any one of the seventh aspect to the eleventh possible implementation forms of the seventh aspect, in a twelfth possible implementation form of the seventh aspect, the receiving unit is further configured to receive a fourth message, the fourth message is used to delete the first EPS bearer, and the UE further includes a deletion unit configured to delete the first EPS bearer and first QoS flow information corresponding to the first EPS bearer.

[0098] With reference to any one of the seventh aspect to the twelfth possible implementation forms of the seventh aspect, in a thirteenth possible implementation form of the seventh aspect, the first QoS flow information is included in a protocol configuration option PCO.

[0099] With reference to the first or second possible implementation manner of the seventh aspect, in a fourteenth possible implementation manner of the seventh aspect, the first information is included in a protocol configuration option PCO.

[0100] Referring to the third possible implementation manner of the seventh aspect, in a fifteenth possible implementation manner of the seventh aspect, the second information is included in a protocol configuration option PCO.

[0101] With reference to any one of the 15th possible implementation forms of the 7th aspect to the 7th aspect, in a 16th possible implementation form of the 7th aspect, the storage unit stores the first QoS flow information in the first EPS bearer context, or stores index information of the first QoS flow information in the context information of the first EPS bearer, and the index information is specifically configured to include the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier.

[0102] Referring to any one of the seventh to sixteenth possible implementation forms of the seventh aspect, in a seventeenth possible implementation form of the seventh aspect, the UE further includes a deletion unit configured to delete a second EPS bearer context, the second EPS bearer being an EPS bearer related to the UE and having no corresponding QoS flow information.

[0103] With reference to any one of the seventh to seventeenth possible implementation forms of the seventh aspect, in an eighteenth possible implementation form of the seventh aspect, the receiving unit is further configured to receive a handover command, the handover command including index information of one or more QoS flows, the index information including a QoS flow identifier or a combination of a QoS flow identifier and a PDU session identifier, and in response, the mobile unit is specifically configured to move from the first communication system to the second communication system based on the handover command.

[0104] With reference to an 18th possible implementation form of the seventh aspect, in a 19th possible implementation form of the seventh aspect, the determination unit is specifically configured to associate an EPS bearer currently in use with index information that belongs to a QoS flow and is included in the handover command, and to delete an EPS bearer that is in the currently used EPS bearer and is not associated with index information of a QoS flow.

[0105] With reference to a 19th possible implementation form of the seventh aspect, in a 20th possible implementation form of the seventh aspect, the determination unit is more specifically configured to obtain an EPS bearer context corresponding to index information of the QoS flow, or to obtain an EPS bearer identifier corresponding to index information of the QoS flow.

[0106] With reference to any one of the 20 possible implementation forms of the 7th aspect to the 7th aspect, in a 21st possible implementation form of the 7th aspect, the first communication system is a 4th generation communication system, the second communication system is a 5th generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0107] According to an eighth aspect, there is provided a core network entity configured to move a user equipment (UE) from a first communication system to a second communication system, the core network entity comprising: a determining unit configured to determine first Quality of Service (QoS) flow information that is of the second communication system and corresponds to a first EPS bearer of the UE in the first communication system; a transmitting unit configured to transmit a first message, the first message being used to set up or modify the first EPS bearer for the UE in the first communication system, the first message including the first QoS flow information; a storing unit configured to store the first QoS flow information; and the determining unit, when the UE moves from the first communication system to the second communication system, the first core network entity configured to determine QoS flow information to be used by the UE in the second communication system based on a fourth condition, the fourth condition including the first QoS flow information.

[0108] Referring to the eighth aspect, in a first possible implementation form of the eighth aspect, the core network entity further includes a receiving unit configured to receive first information transmitted by the UE in a process of establishing a PDN connection in the first communication system, and the determining unit is further configured to determine, based on the first information, that the PDN connection is movable from the first communication system to the second communication system.

[0109] Referring to a first possible implementation form of the eighth aspect, in a second possible implementation form of the eighth aspect, the first information includes information used to indicate that the PDN connection is movable to a second communication system, or the first information includes information used to indicate that a service and session continuity (SSC) mode of a PDU session corresponding to the PDN connection in the second communication system is a specified mode.

[0110] Referring to the eighth aspect, in a third possible implementation form of the eighth aspect, the core network entity further includes a receiving unit configured to receive second information transmitted by the UE in the process of establishing a PDN connection in the first communication system, where the second information is used to indicate an SSC mode of a PDU session corresponding to the PDN connection in the second communication system.

[0111] With reference to any one of the eighth aspect to the third possible implementation forms of the eighth aspect, in a fourth possible implementation form of the eighth aspect, the first quality of service QoS flow information includes one or more QoS rules.

[0112] Referring to any one of the eighth aspect to the fourth possible implementation forms of the eighth aspect, in a fifth possible implementation form of the eighth aspect, the first EPS bearer is a default bearer, and the first quality of service QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0113] With reference to the fourth or fifth possible implementation form of the eighth aspect, in a sixth possible implementation form of the eighth aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0114] Referring to the eighth aspect, in a seventh possible implementation form of the eighth aspect, the determination unit is further configured to obtain a first QoS flow identifier, and the first QoS flow identifier is obtained after a specific value is added to the first EPS bearer identifier, or the first QoS flow identifier is obtained after a specific field is added to the first EPS bearer identifier.

[0115] With reference to any one of the eighth aspect to the seventh possible implementation forms of the eighth aspect, in an eighth possible implementation form of the eighth aspect, the first message is used to set up a first EPS bearer for a UE in a first communication system, and the determination unit is specifically configured to map the first EPS bearer context to first QoS flow information of a second communication system, or the first message is used to modify a first EPS bearer for a UE in the first communication system, and the determination unit is specifically configured to map the context of the modified first EPS bearer to first QoS flow information of the second communication system.

[0116] Referring to an eighth possible implementation form of the eighth aspect, in a ninth possible implementation form of the eighth aspect, the first message is used to set up a first EPS bearer for the UE in the first communication system, and the determination unit is further configured to allocate a QoS flow identifier to the UE or map a bearer identifier of the first EPS bearer to the QoS flow identifier.

[0117] Referring to an eighth possible implementation form of the eighth aspect, in a tenth possible implementation form of the eighth aspect, the first message is used to modify a first EPS bearer for the UE in the first communication system, and the determination unit is further configured to determine that the first EPS bearer has corresponding first QoS flow information of the second communication system.

[0118] With reference to the eighth to tenth possible implementation forms of the eighth aspect, in an eleventh possible implementation form of the eighth aspect, the storage unit is specifically configured to store a correspondence relationship between a bearer identifier of a first EPS bearer and first QoS flow information, or to store a correspondence relationship between a first EPS bearer context and the first QoS flow information, or to store a correspondence relationship between a first EPS bearer context and index information of the first QoS flow, wherein the index information includes the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier, or the UE stores the correspondence relationship between the first EPS bearer and the first QoS flow, or the UE stores the correspondence relationship between the first EPS bearer and index information of the first QoS flow, wherein the index information includes the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier.

[0119] Referring to an eleventh possible implementation form of the eighth aspect, in a twelfth possible implementation form of the eighth aspect, the receiving unit is further configured to receive second information sent by a second core network entity, the second information including a linked bearer identifier and a bearer identifier movable to the second communication system, or including a PDN connection context, the PDN connection context including an EPS bearer context movable to the second communication system, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE, the determining unit is further configured to generate second QoS flow information of the second communication system based on a fifth condition, the second QoS flow information including QoS flow information corresponding to an active EPS bearer of the UE and determined by the second core network entity, and the fifth condition including the second information and a correspondence relationship.

[0120] Referring to a twelfth possible implementation form of the second aspect, in a thirteenth possible implementation form of the second aspect, the receiving unit is further configured to receive a PDN connection context and first QoS flow status information sent by a second core network entity, the first QoS flow status information being used to identify a QoS flow corresponding to an active EPS bearer of the UE, and the determining unit is further configured to determine second QoS flow information of the second communication system based on a fifth condition, the second QoS flow information including a QoS flow corresponding to an active EPS bearer of the UE and determined by the second core network entity, and the fifth condition including the first QoS flow information and a correspondence relationship.

[0121] With reference to any one of the eighth aspect to the thirteenth possible implementation forms of the eighth aspect, in a fourteenth possible implementation form of the eighth aspect, the first QoS flow information is included in a protocol configuration option PCO.

[0122] With reference to the first or second possible implementation manner of the eighth aspect, in a fifteenth possible implementation manner of the eighth aspect, the first information is included in a protocol configuration option PCO.

[0123] Referring to the third possible implementation manner of the eighth aspect, in a sixteenth possible implementation manner of the eighth aspect, the second information is included in a protocol configuration option PCO.

[0124] With reference to any one of the 8th to 16th possible implementation forms of the 8th aspect, in a 17th possible implementation form of the 8th aspect, the first communication system is a 4th generation communication system, the second communication system is a 5th generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0125] According to a ninth aspect, a core network entity is provided, configured to move a user equipment UE from a first communication system to a second communication system. The core network entity comprises: an acquiring unit configured to acquire first status information and a PDN connection context when the UE moves from the first communication system to the second communication system; a determining unit configured to determine second information based on a sixth condition, where the second information is used by the first core network entity to determine QoS flow information to be used by the UE in the second communication system, the sixth condition including the first status information and the PDN connection context; and a transmitting unit configured to transmit the second information, where the acquiring unit is further configured to receive third information sent by the first core network entity, where the determining unit is further configured to generate second status information based on a seventh condition, where the seventh condition includes the third information; and the transmitting unit is further configured to transmit a second message to the UE, where the second message includes the second status information, and the second status information is used by the UE to determine QoS flow information to be used in the second communication system.

[0126] Referring to the ninth aspect, in a first possible implementation form of the ninth aspect, the first status information is first EPS bearer status information, the second status information is second EPS bearer status information, the first EPS bearer status information is used to identify an active EPS bearer that belongs to the UE and has corresponding QoS flow information, and the second EPS bearer status information is used to identify an active EPS bearer that belongs to the UE, has corresponding QoS flow information, and is determined by a second core network entity.

[0127] Referring to the ninth aspect, in a second possible implementation form of the ninth aspect, the first status information is first QoS flow status information, the second status information is second QoS flow status information, the first QoS flow status information is used to identify a QoS flow corresponding to an active EPS bearer of the UE, and the second QoS flow status information is used to identify a QoS flow corresponding to an active EPS bearer of the UE and determined by a second core network entity.

[0128] Referring to the first possible implementation form of the ninth aspect, in a third possible implementation form of the ninth aspect, the third information includes a bearer identifier of an active EPS bearer belonging to the UE and determined by the first core network entity, or the third information includes second QoS flow status information determined by the first core network entity.

[0129] Referring to the first possible implementation form of the ninth aspect, in a fourth possible implementation form of the ninth aspect, the determination unit is specifically configured to determine second information based on an EPS bearer intersection set between the first EPS bearer status information and the PDN connection context, where the second information includes a linked bearer identifier and a bearer identifier movable to the second communication system, or includes a PDN connection context, and the PDN connection context includes an EPS bearer context movable to the second communication system.

[0130] Referring to a second possible implementation form of the ninth aspect, in a fifth possible implementation form of the ninth aspect, the determination unit is specifically configured to map the PDN connection context to QoS flow information of a second communication system and determine second information based on a QoS flow intersection set between the mapped QoS flow information and the first QoS flow status information, where the second information includes second QoS flow status information.

[0131] With reference to any one of the ninth aspect to the fifth possible implementation forms of the ninth aspect, in a sixth possible implementation form of the ninth aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0132] According to a tenth aspect, there is provided a user equipment (UE), configured to move the UE from a first communication system to a second communication system, the UE including: an establishment unit configured to establish a first EPS bearer in the first communication system; a mobile unit configured to move the UE from the first communication system to the second communication system; a receiving unit configured to receive a first message, the first message including first Quality of Service (QoS) flow information of the second communication system and corresponding to the first EPS bearer; and a determining unit configured to determine QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the first QoS flow information.

[0133] Referring to the tenth aspect, in a first possible implementation form of the tenth aspect, the first quality of service QoS flow information includes one or more of the following information: a session aggregate maximum bit rate, an SSC mode, a PDU session identifier, and a QoS rule.

[0134] Referring to a first possible implementation form of the tenth aspect, in a second possible implementation form of the tenth aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0135] Referring to the tenth aspect, in a third possible implementation form of the tenth aspect, the determination unit is further configured to obtain a first QoS flow identifier, and the first QoS flow identifier is obtained after the UE adds a specific value to the first EPS bearer identifier, or the first QoS flow identifier is obtained after the UE adds a specific field to the first EPS bearer identifier.

[0136] Referring to any one of the tenth to third possible implementation forms of the tenth aspect, in a fourth possible implementation form of the tenth aspect, the UE further includes a transmitting unit configured to transmit first EPS bearer status information to a second core network entity, where the first EPS bearer status information is used to identify an active EPS bearer of the UE, and the second core network entity is a core network entity in a second communication system and responsible for access and mobility management of the UE.

[0137] Referring to any one of the third possible implementation forms of the tenth to fourth aspects, in a fifth possible implementation form of the tenth aspect, the UE further includes a transmitting unit configured to transmit first QoS flow status information to a second core network entity, the second core network entity being a core network entity in a second communication system and responsible for access and mobility management of the UE, and the first QoS flow status information being used to identify a QoS flow corresponding to an active EPS bearer of the UE.

[0138] Referring to the tenth aspect, in a sixth possible implementation form of the tenth aspect, the first message is a registration accept message, and the N1 session management information parameter of the registration accept message includes the first QoS flow information, or the first message is a PDU session modification message, and the N1 session management information parameter of the PDU session modification message includes the first QoS flow information.

[0139] Referring to the tenth aspect, in a seventh possible implementation manner of the tenth aspect, the first message is a handover command message, and the handover command message includes first QoS flow information.

[0140] With reference to a seventh possible implementation form of the tenth aspect, in an eighth possible implementation form of the tenth aspect, the target to source transparent container of the handover command message includes the first QoS flow information.

[0141] Referring to an eighth possible implementation form of the tenth aspect, in a ninth possible implementation form of the tenth aspect, an access stratum of the UE obtains first QoS flow information from a target to a source transparent container and transmits the first QoS flow information to a non-access stratum of the UE.

[0142] Referring to any one of the ninth possible implementation forms of the tenth aspect to the tenth possible implementation form of the tenth aspect, in a tenth possible implementation form of the tenth aspect, the first message further includes information about a first EPS bearer corresponding to the first QoS flow information.

[0143] Referring to a tenth possible implementation form of the tenth aspect, in an eleventh possible implementation form of the tenth aspect, the information about the first EPS bearer includes a bearer identifier of the first EPS bearer.

[0144] With reference to the tenth or eleventh possible implementation form of the tenth aspect, in a twelfth possible implementation form of the tenth aspect, the UE further includes a deletion unit configured to delete a second EPS bearer context, wherein the second EPS bearer is an EPS bearer belonging to the UE and not included in the first message, or the second EPS bearer is an EPS bearer belonging to the UE and not having corresponding QoS flow information.

[0145] With reference to any one of the tenth to twelfth possible implementation forms of the tenth aspect, in a thirteenth possible implementation form of the tenth aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF+PGW-C).

[0146] According to an eleventh aspect, there is provided a core network entity configured to move a UE from a first communication system to a second communication system, the core network entity including: a receiving unit configured to receive first information sent by a second core network entity when the UE moves from the first communication system to the second communication system, the first information including a PDN connection context, the PDN connection context including an EPS bearer context movable to the second communication system, the second core network entity being a core network entity in the second communication system and responsible for access and mobility management of the UE; and a determining unit configured to determine QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the first PDN connection context.

[0147] Alternatively, the core network entity includes: a receiving unit configured to receive second information transmitted by a second core network entity when the UE moves from the first communication system to the second communication system, the second information including QoS flow status information corresponding to a PDN connection and a PDN movable to the second communication system, the second core network entity being a core network entity in the second communication system responsible for access and mobility management of the UE; and a determining unit configured to determine QoS flow information to be used by the UE in the second communication system based on a first condition, the first condition including the PDN connection and the QoS flow status information. Further, the PDN connections include all PDN connections of the UE in the first communication system, and the core network entity further includes a removing unit configured to remove QoS flows that are in the QoS flows corresponding to EPS bearers of the PDN connections but are not in the QoS flow status information.

[0148] Referring to the eleventh aspect, in a first possible implementation form of the eleventh aspect, the QoS flow information includes one or more of the following information: session aggregate maximum bit rate, SSC mode, PDU session identifier, and QoS rule.

[0149] Referring to a first possible implementation form of the eleventh aspect, in a second possible implementation form of the eleventh aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0150] Referring to any one of the second possible implementation forms of the eleventh aspect to the eleventh aspect, in a third possible implementation form of the eleventh aspect, the first communication system is a fourth generation communication system, the second communication system is a fifth generation communication system, and / or the first core network entity is a session management function entity + control plane PDN gateway (SMF + PGW-C).

[0151] According to a twelfth aspect, there is provided a core network entity configured to move a user equipment (UE) from a first communication system to a second communication system, the core network entity including: an obtaining unit configured to receive first Quality of Service (QoS) flow information of the second communication system corresponding to a first EPS bearer established by the UE in the first communication system when the UE moves from the first communication system to the second communication system; and a transmitting unit configured to transmit a first message including the first QoS flow information to the UE.

[0152] Referring to the twelfth aspect, in a first possible implementation form of the twelfth aspect, the first QoS flow information includes one or more of the following information: a session aggregate maximum bit rate, an SSC mode, a PDU session identifier, and a QoS rule.

[0153] Referring to a first possible implementation form of the twelfth aspect, in a second possible implementation form of the twelfth aspect, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter, or the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a priority, and a packet filter identifier.

[0154] Referring to any one of the second possible implementation forms of the twelfth aspect to the twelfth aspect, in a third possible implementation form of the twelfth aspect, the acquisition unit is further configured to acquire first EPS bearer status information and a PDN connection context, the first EPS bearer status information is used to identify an active EPS bearer of the UE, and the core network entity further includes a determination unit configured to determine third information based on the first EPS bearer status information and the PDN connection context, wherein the third information includes a PDN connection movable to the second communication system and an EPS bearer on the PDN connection, or includes a PDN connection context movable to the second communication system.

[0155] Referring to any one of the 12th to 12th aspects of the second possible implementation forms of the 12th aspect, in a fourth possible implementation form of the 12th aspect, the acquisition unit is further configured to acquire first QoS flow status information and a PDN connection context, where the first QoS flow status information is used to identify a QoS flow corresponding to an active EPS bearer of the UE, the transmission unit is further configured to transmit the first QoS flow status information and the PDN connection context to a first core network entity, and the acquisition unit is further configured to receive second QoS flow information transmitted by the first core network entity, where the second QoS flow information is used to identify a QoS flow corresponding to an active EPS bearer of the UE and determined by the first core network entity.

[0156] Referring to the twelfth aspect, in a fifth possible implementation form of the twelfth aspect, the first message is a registration accept message, and the N1 session management information parameter of the registration accept message includes the first QoS flow information, or the first message is a PDU session modification message, and the N1 session management information parameter of the PDU session modification message includes the first QoS flow information.

[0157] Referring to the twelfth aspect, in a sixth possible implementation manner of the twelfth aspect, the first message is a handover command message, and the handover command message includes the first QoS flow information.

[0158] With reference to a sixth possible implementation manner of the twelfth aspect, in a seventh possible implementation manner of the twelfth aspect, the target to the source transparent container of the handover command message includes the first QoS flow information.

[0159] With reference to any one of the seventh possible implementation forms of the twelfth to twelfth aspects, in an eighth possible implementation form of the twelfth aspect, the first message further includes information about a first EPS bearer corresponding to the first QoS flow information.

[0160] With reference to an eighth possible implementation form of the twelfth aspect, in a ninth possible implementation form of the twelfth aspect, the information about the first EPS bearer includes a bearer identifier of the first EPS bearer.

[0161] Referring to any one of the ninth possible implementation forms of the twelfth to twelfth aspects, in a tenth possible implementation form of the twelfth aspect, the first communication system is a fourth generation communication system and the second communication system is a fifth generation communication system.

[0162] According to a thirteenth aspect, there is provided a user equipment (UE), the user equipment (UE) including: a memory, a processor, a communication interface, and a bus, wherein the memory stores code and data, the processor, the memory, and the communication interface are connected by using the bus, and the processor executes code in the memory such that the user equipment (UE) performs the method for moving between communication systems provided in any one of the first aspect and possible implementation forms of the first aspect, or the method for moving between communication systems provided in any one of the fourth aspect and possible implementation forms of the fourth aspect.

[0163] According to a fourteenth aspect, there is provided a core network device, the core network device including: a memory, a processor, a communication interface, and a bus, wherein the memory stores code and data, the processor, the memory, and the communication interface are connected using the bus, and the processor executes code in the memory such that the core network device performs the method for moving between communication systems provided in any one of the second aspect and possible implementation forms of the second aspect, or the method for moving between communication systems provided in the fifth aspect and any one of the possible implementation forms of the fifth aspect.

[0164] According to a fifteenth aspect, there is provided a core network device, the core network device including: a memory, a processor, a communication interface, and a bus, wherein the memory stores code and data, the processor, the memory, and the communication interface are connected using the bus, and the processor executes code in the memory such that the core network device performs the method for moving between communication systems provided in the third aspect and any one of possible implementation forms of the third aspect, or the method for moving between communication systems provided in the sixth aspect and any one of possible implementation forms of the sixth aspect.

[0165] According to a sixteenth aspect, there is provided a system, the system including: a user equipment (UE), a first core network entity, and a second core network entity, wherein the user equipment is the user equipment provided in the seventh aspect and any one of its possible implementations, or the tenth aspect and any one of its possible implementations, or the thirteenth aspect; and / or the first core network entity is a core network device provided in the eighth aspect and any one of its possible implementations, or the eleventh aspect and any one of its possible implementations, or the fourteenth aspect; and / or the second core network entity is a core network device provided in the ninth aspect and any one of its possible implementations, or the twelfth aspect and any one of its possible implementations, or the fifteenth aspect.

[0166] Yet another aspect of the present application provides a computer-readable storage medium having stored thereon instructions that, when executed on a computer, cause the computer to carry out a method in the manner described above.

[0167] Yet another aspect of the present application provides a computer program product comprising instructions which, when executed on a computer, cause the computer to carry out a method in the manner described above. [Brief explanation of the drawings]

[0168] [Figure 1] 1 is a system architecture diagram of a communication system according to an embodiment of the present application; [Figure 2] FIG. 1 is a schematic structural diagram of a user equipment according to an embodiment of the present application; [Figure 3]1 is a flowchart of a first method for navigating between communication systems according to an embodiment of the present application. [Figure 4] 4 is a flowchart of a second method for roaming between communication systems according to an embodiment of the present application. [Figure 4A] 10 is a flowchart of a third method for roaming between communication systems according to an embodiment of the present application. [Figure 5] 4 is a flowchart of a UE moving to a second communication system according to an embodiment of the present application; [Figure 6] 10 is another flowchart of a UE moving to a second communication system according to an embodiment of the present application. [Figure 7] 10 is yet another flowchart of a UE moving to a second communication system according to an embodiment of the present application; [Figure 8] 10 is a flowchart of a fourth method for roaming between communication systems according to an embodiment of the present application. [Figure 9] 10 is a flowchart of a fifth method for roaming between communication systems according to an embodiment of the present application. [Figure 10] 4 is a flowchart of a UE moving to a second communication system according to an embodiment of the present application; [Figure 11] 10 is another flowchart of a UE moving to a second communication system according to an embodiment of the present application. [Figure 12] 10 is yet another flowchart of a UE moving to a second communication system according to an embodiment of the present application; [Figure 13] 10 is a flowchart of a sixth method for roaming between communication systems according to an embodiment of the present application. [Figure 14] FIG. 1 is a schematic structural diagram of a user equipment according to an embodiment of the present application; [Figure 15] FIG. 2 is a schematic structural diagram of another user equipment according to an embodiment of the present application; [Figure 16] FIG. 2 is a schematic structural diagram of a first core network device according to an embodiment of the present application; [Figure 17] FIG. 10 is a schematic structural diagram of another first core network device according to an embodiment of the present application; [Figure 18] FIG. 10 is a schematic structural diagram of a second core network device according to an embodiment of the present application; [Figure 19] FIG. 10 is a schematic structural diagram of another second core network device according to an embodiment of the present application; [Figure 20] FIG. 1 is a schematic structural diagram of a user equipment according to an embodiment of the present application; [Figure 21] FIG. 2 is a schematic structural diagram of another user equipment according to an embodiment of the present application; [Figure 22] FIG. 2 is a schematic structural diagram of a first core network device according to an embodiment of the present application; [Figure 23] FIG. 10 is a schematic structural diagram of another first core network device according to an embodiment of the present application; [Figure 24] FIG. 10 is a schematic structural diagram of a second core network device according to an embodiment of the present application; [Figure 25] FIG. 10 is a schematic structural diagram of another second core network device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0169] Before describing this application, technical terms involved in embodiments of this application will first be described.

[0170] A Protocol Data Network (PDN) Connection (or Connectivity) is a combination of a group of EPS bearers established on a UE in a first communication system (e.g., a 4G network), and these EPS bearers have the same IP address and the same Access Point Name (APN). The IP address and APN are used to identify the PDN connection on the UE side and the network side.

[0171] The PDN connection context includes the IP address, APN, PGW address, and context information of each EPS bearer used by the PDN connection.

[0172] An EPS bearer is a data transmission channel in a first communication system (e.g., a 4G network). An active EPS bearer is a data transmission channel established with a specific QoS in the first communication system. An inactive EPS bearer is a data transmission channel that has been deleted from the first communication system.

[0173] EPS bearer status information: In a first communication system (e.g., a 4G network), each EPS bearer has an EPS bearer identifier (EBI), and the EPS bearer status information is used to indicate whether a bearer corresponding to each EBI exists. For example, the EBIs shown in Table 1 range from 0 to 15, and the values corresponding to the EBIs are specifically shown in Table 1. In Table 1, when the EBI is 5 or 7, the corresponding value is 1, which indicates that a corresponding EPS bearer exists, and the values of other EBIs are 0, which indicates that a corresponding bearer does not exist. [Table 1]

[0174] The EPS bearer context includes information such as the QoS information of the EPS bearer, the EPS bearer identifier, and the TFT.

[0175] A PDU session is a group of QoS flows established on a UE in a 5G network, and these QoS flows have the same IP address and the same Data Network Name (DNN). The IP address and DNN are used to identify the PDN connection on the UE and network sides.

[0176] The PDU session context includes the IP address, APN, SMF, and UPF address used by the PDU session, and includes context information for each QoS flow.

[0177] Service and Session Continuity (SSC) modes of PDU sessions: Each PDU session in the second communication system (e.g., 5G) has a continuity description. SSC mode 1 indicates that the PDU session can maintain continuity during the UE mobility process. SSC mode 2 indicates that during the mobility process, the UE can first release the existing PDU session and then create a new PDU session to replace the released PDU session. SSC mode 3 indicates that during the mobility process, the UE can maintain the existing PDU session for a certain period of time, during which time it can create a new PDU session to replace the original PDU session, and after the existing PDU session is terminated, it can release the existing PDU session and only maintain the new PDU session.

[0178] The QoS flow information includes one or more combinations of the following information: QoS information of the QoS flow, a QoS flow identity (QFI), and a QoS flow template. For example, in a 5G communication system, the QoS information may further include one or more combinations of the following information: a 5G QoS indicator (5QI), an allocation and retention priority (ARP), a guaranteed flow bit rate (GFBR), a maximum flow bit rate (MFBR), and notification control, which are QoS-enabled. The QoS flow information is used to describe the QoS flow and includes, but is not limited to, the information described above. The QoS flow information may also be referred to as a QoS parameter, and may be replaced with the QoS parameter in embodiments of the present application.

[0179] The Protocol Configuration Option (PCO) is a parameter used for information transfer between the UE and the PDN Gateway (PGW), and the Mobility Management Entity (MME) and base station do not parse the syntax of the PCO.

[0180] The difference between an Extended PCO and a PCO is that since the size of a PCO is limited, the PCO is extended to carry more data, resulting in an Extended PCO.

[0181] 1 illustrates a system architecture of a communication system according to an embodiment of the present application. The system architecture includes a first communication system and a second communication system. In FIG. 1, for example, the first communication system is a fourth generation (4G) communication system, and the second communication system is a fifth generation (5G) communication system.

[0182] Referring to FIG. 1 , the communication system includes a UE, an Evolved UMTS Terrestrial Radio Access Network (E-UERAN), a mobility management entity (MME), a Serving Gateway (SGW), a User Plane Function (UPF)+PDN Gateway-User plane (PGW-U), a Session Management Function (SMF)+PDN Gateway-Control plane (PGW-C), a Policy Control Function (PCF)+Policy and Charging Rules Function (PCRF), a Home Subscriber Server (HSS)+Unified Data Management (UDM), an Access and Mobility Management Function (AMF), and a 5G Radio Access Network (5G-RAN).

[0183] The E-UTRAN is a base station on the 4G side, and a UE may access the 4G communication system by using this base station. The 5G-RAN is a base station on the 5G side, and a UE may access the 5G communication system by using this base station. The 5G-RAN may be a base station obtained as a further evolution of the E-UTRAN, which enables a UE to access the 5G communication system by using this base station, or the 5G-RAN may be a dedicated base station used by a UE to access the 5G communication system. The core network entities in FIG. 1 may be referred to as core network devices.

[0184] The MME is a 4G core network device that is responsible for performing authentication, authorization, mobility management, and session management for the UE, and is the entity that allocates the Linked EPS Bearer ID (LBI) of the UE's PDN connection in 4G.

[0185] SGW is a 4G core network device (core network gateway) that is responsible for data forwarding, downlink data storage, etc.

[0186] The UPF+PGW-U is a core network device shared by 4G and 5G, in other words, a core network device integrated in 4G and 5G, and includes the functions of the UPF and the PGW-U. The UPF is a user plane device in the 5G core network, providing user plane services for UE PDU sessions and serving as an interface gateway between the carrier network and external networks. The PGW-U is a user plane device in the 4G core network, providing user plane services for UE PDN connections and serving as an interface gateway between the carrier network and external networks. If the device including the functions of the UPF and the PGW-U is the same device, the UPF+PGW-U may also be referred to as the PGW-U+UPF.

[0187] The SMF+PGW-C is a core network device shared by 4G and 5G, in other words, an integrated core network device in 4G and 5G, and includes the functions of the SMF and the PGW-C. The SMF is a control plane device in the 5G core network, providing control plane services for a UE's PDU session, managing 5G PDU sessions and 5G QoS, allocating IP addresses to the UE, and selecting a UPF for the UE. The PGW-C is a control plane device in the 4G core network, providing user plane services for a UE's PDN connection, allocating IP addresses to the UE, and setting up EPS bearers for the UE. If the device including the functions of the SMF and the PGW-C is the same device, the SMF+PGW-C may also be referred to as the PGW-C+SMF.

[0188] The PCF+PCRF is a core network device shared by 4G and 5G, in other words, a core network device integrated in 4G and 5G, and includes a PCF and a PCRF. The PCRF is a 4G core network device and is responsible for generating policies used by users to set up data bearers. The PCF is a 5G core network device and has functions similar to those of the PCRF. If the device including the PCF functions and the PCRF functions is the same device, the PCF+PCRF may also be referred to as the PCRF+PCF.

[0189] The UDM+HSS is a core network device shared by 4G and 5G, in other words, a core network device integrated in 4G and 5G, and includes an HSS and a UDM. The HSS is a 4G core network device configured to store user subscription data. The SDM is a 5G core network device configured to store user subscription data. If the device including the functions of the HSS and the UDM is the same device, the UDM+HSS may also be referred to as an HSS+UDM.

[0190] The AMF is a 5G core network device used for user authentication and authorization and for managing user mobility.

[0191] The Nx interface is an interface between the MME and the AMF. At present, this interface is optional. When a UE moves between 4G and 5G, the UE context may be transferred using the Nx interface. When a PDN connection established by a UE in a 4G network can be seamlessly migrated to a 5G network, the MME selects an SMF+PGW-C integrated in 5G and 4G for the UE. Seamless migration means that the IP address remains unchanged and the PGW-C remains unchanged.

[0192] FIG. 2 is a schematic structural diagram of a UE according to an embodiment of the present application. The UE may be a mobile phone, a tablet computer, a notebook computer, a notebook, a portable electronic device, etc. As shown in FIG. 2, the UE may include elements such as a memory, a processor, a radio frequency (RF) circuit, and a power supply. The memory may be configured to store software programs and modules. The processor executes the software programs and modules stored in the memory to perform various functional applications of the UE and process data. The memory may mainly include a program storage area and a data storage area. The program storage area may store an operating system, application programs required for at least one function, etc., and the data storage area may store data generated based on the use of the UE, etc. Furthermore, the memory may include a high-speed random access memory and may further include a non-volatile memory, etc. The processor is the control center of the UE and is connected to all elements of the entire UE using various interfaces and cables. The processor runs or executes software programs and / or modules stored in the memory and accesses data stored in the memory to perform various functions of the UE and process data, so as to perform overall monitoring of the UE. Optionally, the processor may include one or more processing units. Preferably, an application processor and a modem processor may be incorporated into the processor. The application processor mainly processes an operating system, a user interface, application programs, etc., and the modem processor mainly processes wireless communications. The RF circuitry may be configured to receive and transmit information or receive and transmit signals during a call. Generally, the RF circuitry includes, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier (LNA), a duplexer, etc. The UE further includes a power supply that provides power to each element.Preferably, the power source may be logically connected to the processor by using a power management system so as to perform functions such as charging management, discharging management, and power consumption management by using the power management system.

[0193] Although not shown, the UE may further include an input unit, a display unit, a sensor module, an audio module, a WiFi module, a Bluetooth module, etc., which will not be described in detail herein.

[0194] 3 is a flowchart of a method for moving between communication systems according to an embodiment of the present application. Referring to FIG. 3, the method is applied to the communication system shown in FIG. 1 and is used to move a UE from a first communication system to a second communication system. The method may include the following steps:

[0195] Step 201: A first core network entity determines first QoS flow information that belongs to a second communication system and corresponds to a first EPS bearer of a UE in the first communication system, and stores the first QoS flow information.

[0196] A PDN connection in the first communication system corresponds to a PDU session in the second communication system. One PDN connection may include multiple EPS bearers, and one PDU session may include multiple QoS flows. A UE may establish multiple PDN connections in the first communication system, and among the multiple PDN connections, one or more PDN connections may be movable to the second communication system. A PDN connection that can be moved to a second communication system means that the PGW used by the PDN connection is an SMF+PGW-C integrated in 4G and 5G, or that when the UE moves from the first communication system to the second communication system, a PDU session corresponding to the PDN connection can be established in the second communication system, and the PDN connection has the same IP address as the PDU session, or that the PGW used by the PDN connection is an SMF+PGW-C integrated in 4G and 5G, and that when the UE moves from the first communication system to the second communication system, a PDU session corresponding to the PDN connection can be established in the second communication system, and the PDN connection has the same IP address as the PDU session.

[0197] The first EPS bearer is an EPS bearer included in a PDN connection established by a UE in a first communication system, and may be one EPS bearer or a group of EPS bearers. The first QoS flow corresponds to the first EPS bearer, and the first QoS flow may include one QoS flow or a group of QoS flows. One EPS bearer may correspond to one or more QoS flows. The first QoS flow information is information obtained after the first EPS bearer is mapped to a QoS flow in the second communication system, for example, the mapping is performed based on a predetermined mapping rule. Alternatively, the first QoS flow information is generated based on the first EPS bearer. Not all EPS bearers on a UE can be moved to the second communication system. For example, non-GBR EPS bearers cannot be moved to the second communication system. Alternatively, when a PDN connection cannot be moved to the second communication system, none of the EPS bearers corresponding to that PDN connection can be moved to the second communication system. EPS bearers that cannot be moved to the second communication system do not have corresponding QoS flow information.

[0198] In this embodiment of the present application, the first QoS flow information may include one or more QoS rules. When the first EPS bearer is a default bearer, the first QoS flow information includes one or more of the following information: a session aggregate maximum bit rate (AMBR), an SSC mode, a PDU session identifier, and a QoS rule. The QoS rule may be one or more QoS rules. Specifically, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a precedence, or a packet filter. Alternatively, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a precedence, and a packet filter identifier. The packet filter includes a packet filter attribute and a packet filter ID. The first QoS flow information may further include one or more combinations of the following information: 5QI, ARP, GFBR, MFBR, and notification control for the QoS flow. It may be understood that the default bearer of the UE is configured in a process in which the UE establishes a PDN connection in the first communication system. In other words, configuring a default bearer for the UE may be understood as establishing a PDN connection for the UE. Specifically, the UE may request to establish a PDN connection by using an attach request or a PDN connectivity request. In the process of establishing a PDN connection for the UE in the first communication system, information about a PDU session belonging to the second communication system and corresponding to the PDN connection is transmitted to the UE by using a request message used to configure the default bearer. The information about the PDU session includes one or more of a session aggregate maximum bit rate (session AMBR), an SSC mode, and a PDU session identifier.

[0199] For example, a method used by the SMF+PGW-C to determine first QoS flow information in a 5G communication system may be as follows: the SMF+PGW-C generates a 5G QoS rule based on a traffic flow template (TFT) of an EPS context. The method specifically includes generating the QoS rule based on one or more policy and charging control (PCC) rules used to generate the TFT of the EPS bearer. The priority of each PCC is set to the priority of the QoS rule, and one or more packet filters of the PCC are set to the packet filters of the QoS rule. Furthermore, the SMF+PGW-C may further assign a QoS rule identifier to the QoS rule. For example, the SMF+PGW-C may further set the QCI of the EPS bearer to 5G 5QI, the GBR of the EPS bearer to 5G GFBR, the MBR of the EPS bearer to 5G MFBR, and the EBI of the default bearer of the PDN connection to a 5G PDU session identifier.

[0200] The method may further include the UE acquiring a first QoS flow identifier (QFI), where the first QoS flow identifier is acquired after the UE adds a specific value to the first EPS bearer identifier (EBI), or the first QoS flow identifier is acquired after the UE adds a specific field to the first EPS bearer identifier.

[0201] For example, the QFI is obtained after a specific value is added to the EBI, for example, the specific value is 10. If the EBI is 5, the QFI is 15, and if the EBI is 6, the QFI is 16. As another example, the QFI is obtained after a specific field is added to the EBI, for example, the specific field is 1 byte. If the EBI is 1 byte, the QFI is obtained after adding 1 byte after the EBI. If 1 byte of the EBI is 00000101, the QFI is 2 bytes obtained after adding 1 byte: 00000101 00000001.

[0202] It should be noted that the specific values and the specific numerical values of the specific fields may be set based on requirements, which are not specifically limited in this embodiment of the present invention.

[0203] Furthermore, the first core network entity storing the first QoS flow information may include storing the first QoS flow information by the first core network entity using a first EPS bearer identifier (EPS Bearer the first core network entity storing a correspondence relationship between a first EPS bearer context and the first QoS flow information; or the first core network entity storing a correspondence relationship between a first QoS flow identifier and the first EPS bearer context; or the first core network entity storing a correspondence relationship between the first EPS bearer context and both the first QoS flow identifier and a session identifier, where the session identifier is an identifier of a PDU session to which the first QoS flow belongs; or storing a correspondence relationship between the first EPS bearer and the first QoS flow; or storing a correspondence relationship between the first EPS bearer and the first QoS flow, or storing a correspondence relationship between the first EPS bearer and index information of the first QoS flow, where the index information includes the first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier. The first core network entity may store the first QoS flow information in a bearer context of the first EPS bearer of the UE, or the first core network entity may generate a QoS flow context of the second communication system for the UE, where the QoS flow context includes the EBI or the first EPS bearer information.

[0204] In this embodiment of the present application, the first communication system may be a 4G communication system, the second communication system may be a 5G communication system, and the first core network entity may be an SMF+PGW-C network element integrated in the two communication systems, such that the SMF+PGW-C may determine first QoS flow information in the 5G communication system based on the EPS bearer context of the UE in the 4G communication system. The QoS flow information may also be referred to as a 5G QoS rule or a 5G QoS parameter. The first QoS flow information includes one or more combinations of the following information: QoS information of the QoS flow, a QoS flow identifier QFI, a QoS rule, information about the PDU session to which the QoS flow belongs, and a QoS flow template. The QoS information further includes one or more combinations of the following information: 5QI, ARP, GFBR, MFBR, and notification control related to QoS.

[0205] For example, the SMF+PGW-C may generate the QoS of the 5G QoS flow based on the QoS of the EPS bearer in the first EPS bearer, and generate a 5G QoS flow template or QoS rule based on the TFT of the EPS bearer.

[0206] Step 202: A first core network entity sends a first message, where the first message is used to set up or modify a first EPS bearer for the UE in the first communication system, and the first message includes first QoS flow information.

[0207] When a first core network entity sets up or modifies a first EPS bearer for a UE in a first communication system, the first core network entity may send a first message including the first QoS flow information to the UE so that the UE obtains first QoS flow information corresponding to the first EPS bearer.

[0208] When the first message is used to set up a first EPS bearer for a UE in a first communication system, the above-mentioned step 201 specifically includes: the first core network entity maps the first EPS bearer context to first QoS flow information of the second communication system. When the first message is used to modify a first EPS bearer for a UE in a first communication system, the above-mentioned step 201 specifically includes: the first core network entity maps the context of the modified first EPS bearer to first QoS flow information of the second communication system. The mapping described herein may be understood as generating the first QoS flow information based on the first EPS bearer context or performing mapping based on a predetermined mapping rule. The first QoS flow information may be complete first QoS flow information obtained after the first core network entity performs mapping, or may be partial information of the first QoS flow information obtained after the first core network entity performs mapping, where the partial information is first QoS flow information that the UE cannot obtain by local mapping. For example, the partial information includes partial QoS rule information and partial PDU session information. The partial QoS rule information includes one or more of a QoS rule ID, a precedence, and a packet filter identifier, and the partial PDU session information includes one or more of a session AMBR, an SSC mode, and a PDU session identifier. Sending partial information can reduce the amount of air interface data transmitted and save resources.

[0209] Specifically, in the communication system shown in Figure 1, the first core network entity SMF+PGW-C may send first QoS flow information to the SGW by using a first message, the SGW forwards the first QoS flow information to the MME, and then the MME transmits the first QoS flow information to the UE; alternatively, the first core network entity SMF+PGW-C may send the first QoS flow information to the SGW, the SGW forwards the first QoS flow information to the MME, and then the MME transmits the first QoS flow information to the UE by using a first message. The first message may include a protocol configuration option (PCO), and the first QoS flow information may be included in the PCO. The PCO may be a general PCO or an extended PCO.

[0210] If the first message is used to set up a first EPS bearer for the UE in the first communication system, the method further includes a step of the first core network entity allocating a QoS flow identifier to the UE, in particular allocating a corresponding QoS flow identifier to the QoS flow included in the first QoS flow information determined in step 201, or mapping the bearer identifier of the first EPS bearer to the QoS flow identifier. If the first message is used to modify a first EPS bearer for the UE in the first communication system, the method further includes a step of a first core network entity determining that the first EPS bearer has first QoS flow information of a corresponding second communication system, specifically, a step of the first core network entity determining whether the first EPS bearer of the UE in the first communication system has first QoS flow information of a corresponding second communication system, and a step of determining the first QoS flow information based on step 201 when the first core network entity determines that the first EPS bearer has corresponding first QoS flow information. The first EPS bearer having first QoS flow information of a corresponding second communication system may be specifically understood as follows: the context information of the first EPS bearer includes the first QoS flow information, or the UE separately stores the first EPS bearer context and the first QoS flow information. The context information of the first EPS bearer includes index information of the first QoS flow, and the index information may be a QoS flow ID or a combination of a QoS flow ID and a PDU session ID. In this embodiment of the present application, the QoS flow information and the information about the QoS flow have the same meaning and are understood in the same way in other parts of this specification. Details will not be described.

[0211] Step 203: When the UE receives the first message sent by the first core network entity, the UE may store first QoS flow information.

[0212] When the UE receives a first message sent by a first core network entity and including first QoS flow information, the UE may store the first QoS flow information. When the UE stores the first QoS flow information, the UE may store a correspondence between a bearer identifier of the first EPS bearer and the first QoS flow information, or the UE stores a correspondence between the first EPS bearer context and the first QoS flow information, or the UE stores a correspondence between the first EPS bearer context and index information of the first QoS flow, where the index information may be a QoS flow ID or a combination of a QoS flow ID and a PDU session ID, or the UE adds the first QoS flow information to the first EPS bearer context, or the UE stores the correspondence between the first EPS bearer context and index information of the first QoS flow, where the index information may be a QoS flow ID or a combination of a QoS flow ID and a PDU session ID, or the UE adds the first QoS flow information to the first EPS bearer context, or the UE stores the first QoS flow information. The UE may separately store the EPS bearer context and the first QoS flow information, and the UE may add index information of the first QoS flow to the context information of the first EPS bearer, where the index information may be a QoS flow ID or a combination of a QoS flow ID and a PDU session ID; alternatively, the UE may store a correspondence between the first EPS bearer and the first QoS flow; or the UE may store a correspondence between the first EPS bearer and index information of the first QoS flow, where the index information includes a first QoS flow identifier or a combination of the first QoS flow identifier and a PDU session identifier. Furthermore, the UE may store a correspondence between a bearer identifier of the first EPS bearer and the first QoS flow information. This may be specifically understood as storing a correspondence between a bearer identifier of the first EPS bearer and the first QoS flow information in the first EPS bearer context. The UE's storing of the correspondence between the first EPS bearer and the first QoS flow information may be specifically understood as storing the first QoS flow information in the first EPS bearer context, or adding index information of the first QoS flow to the context information of the first EPS bearer, where the index information may be a QoS flow ID or a combination of a QoS flow ID and a PDU session ID.The PDU session ID in this specification is the ID of the PDU session to which the QoS flow belongs, and specifically, the PDU session indicated by the PDU session ID includes the first QoS flow.

[0213] Step 204: The UE moves from the first communication system to the second communication system.

[0214] Optionally, the UE moves from the first communication system to the second communication system by using a handover process. The UE receives a handover command in the handover process. The handover command includes index information of one or more QoS flows, where the index information includes a QoS flow identifier or a combination of the QoS flow identifier and a PDU session identifier. The handover command is sent to the UE by a base station in the first communication system, and includes configuration information allocated to the UE by the base station in the second communication system. The configuration information is used by the UE to access the base station in the second communication system. The configuration information includes a QoS flow identifier or a combination of the QoS flow identifier and a PDU session ID.

[0215] Step 205: The UE determines QoS flow information to be used by the UE in the second communication system based on a first condition, where the first condition includes the first QoS flow information.

[0216] The first QoS flow information in step 205 is consistent with the first QoS flow information in step 201. Similarly, for the method used by the UE to determine the first QoS flow information, please refer to the description of step 201. In this embodiment of the present application, the details will not be described again here.

[0217] Optionally, after the UE receives the handover command, a method used by the UE to determine the QoS flow information to be used in the second communication system may be as follows: the UE associates the currently used EPS bearer with the index information of the QoS flow and included in the handover command, and the UE deletes the EPS bearer that is in the currently used EPS bearer and is not associated with the index information of the QoS flow. The currently used EPS bearer may be understood as an ongoing EPS bearer for the UE or an active EPS bearer for the UE.

[0218] Specifically, the UE associating the currently used EPS bearer with the index information of the QoS flow that is included in the handover command includes the UE obtaining an EPS bearer context corresponding to the index information of the QoS flow, or the UE obtaining an EPS bearer identifier corresponding to the index information of the QoS flow. Specifically, the UE obtains the index information of the QoS flow from the handover command, and locally searches for an EPS bearer identifier corresponding to the EPS bearer context or the index information. The UE locally deletes EPS bearers other than those that can be found on the UE.

[0219] Step 206: In the process of the UE moving from the first communication system to the second communication system, or after the UE moving from the first communication system to the second communication system, the first core network entity determines the QoS flow information to be used by the UE in the second communication system based on a fourth condition, where the fourth condition includes the first QoS flow information.

[0220] The QoS flow information used by the UE in the second communication system may be QoS flow information corresponding to one or more PDU sessions of the UE, or may be information about one or more PDU sessions of the UE. When the QoS flow information includes information about multiple PDU sessions, the corresponding information may be referred to as an information set. Specifically, the QoS flow information may be understood as a set of one or more QoS flow information, or as a set of one or more PDU session information. When the QoS flow information includes only one QoS flow information or only one PDU session information, it may be understood that the set includes only one QoS flow information or only one PDU session information. This understanding is similar to that in other parts of this specification. Details will not be described again.

[0221] Specifically, the UE and the first core network entity may determine QoS flow information that may be used by the UE in the second communications system based on the first QoS flow information included in the first condition, so that the UE maps EPS bearers in the first communications system to QoS flows in the second communications system, and the UE is seamlessly transitioned from the first communications system to the second communications system and can communicate with or send data to the second communications system by using the QoS flow information.

[0222] It should be noted that there may be no order between step 204 and both steps 205 and 206. With respect to the UE, the UE may first move from a first communication system to a second communication system and then determine the QoS flow information used in the second communication system, or the UE first determines the QoS flow information used in the second communication system and then moves from the first communication system to the second communication system, or the UE determines the QoS flow information used in the second communication system in the process of moving from the first communication system to the second communication system. This is not particularly limited in this embodiment of the present application. In the illustrative example of FIG. 3, step 204 is performed before step 205 and step 206.

[0223] Referring to FIG. 4, before step 201, the method further includes step 200a and step 200b.

[0224] Step 200a: In a process of establishing a PDN connection in a first communication system, the UE sends first information to a first core network entity, and the first information is used by the first core network entity to determine that the PDN connection is movable from the first communication system to a second communication system.

[0225] The PDN connection may be established during an attach process, or may be established based on a PDN connection establishment request requested by the UE.

[0226] Furthermore, the first information includes information used to indicate that the PDN connection is movable to the second communication system. Specifically, the first information includes information directly used to indicate that the PDN is movable to the second communication system. Alternatively, the first information includes information used to indicate that the service and session continuity SSC mode of the PDU session corresponding to the PDN connection in the second communication system is a designated mode, and the designated mode may be preset. Specifically, the first information includes information indirectly used to indicate that the PDN is movable to the second communication system. For example, the designated mode may be mode 1 in the SSC mode. Specifically, when the first information includes information used to indicate that the SSC mode of the PDU session corresponding to the PDN connection in the second communication system is mode 1, the first information indicates that the PDN connection is movable to the second communication system.

[0227] Specifically, in the process of establishing a PDN connection in the first communication system, the UE may send first information to the first core network entity by using a PCO, specifically, the first information is included in the PCO, which may be a general PCO or an extended PCO.

[0228] Step 200b: When the first core network entity receives the first information sent by the UE, the first core network entity determines, based on the first information, that the PDN connection is movable from the first communication system to the second communication system.

[0229] Specifically, when the first information includes information used to indicate that the PDN connection is movable to the second communication system, the first core network entity may directly determine that the PDN connection is movable from the first communication system to the second communication system when it receives the first information transmitted by the UE. When the first information includes information used to indicate that the SSC mode of the PDU session corresponding to the PDN connection in the second communication system is a designated mode, the first core network entity receives the first information transmitted by the UE, the first core network entity determines whether the SSC mode indicated in the first information is a designated mode, and if the SSC mode is a designated mode, the first core network entity determines that the PDN connection is movable from the first communication system to the second communication system.

[0230] Referring to Figure 4A, in the process of establishing a PDN connection in a first communication system, specifically before step 202 in which the first core network entity sends a first message, the method further includes steps 201a and 201b. Specific functions of the SSC mode in Figure 4 are different from those of the SSC mode in Figure 4A. The SSC mode in Figure 4 is a designated mode and is used to indicate that the PDN connection is movable to the second communication system. The SSC mode in Figure 4A is an SC mode for a PDU session expected by the UE and corresponding to the PDN connection in the second communication system.

[0231] Step 201a: In a process of establishing a PDN connection in the first communication system, the UE sends second information to a first core network entity, where the second information is used to indicate an SSC mode of a PDU session corresponding to the PDN connection in the second communication system.

[0232] Specifically, in the process of establishing a PDN connection in the first communication system, the UE may send the second information to the first core network entity by using a PCO, specifically, the second information is included in the PCO, which may be a general PCO or an extended PCO.

[0233] In step 201a, the UE may first send an attach request message or a PDU session creation request message to the MME, and add the second information to the PCO of the message. The MME sends the session creation request to the first core network entity by using the SGW, and the session creation request carries the PCO.

[0234] Step 201b: The first core network entity receives second information sent by the UE, where the second information is used to indicate that the SSC mode of the PDU session corresponds to a PDN connection in the second communication system.

[0235] After receiving the second information, the first core network entity may determine the SSC mode of the PDU session corresponding to the PDN connection in the second communication system based on the SSC mode indicated by the second information, or the first core network entity may determine the SSC mode of the PDU session corresponding to the PDN connection in the second communication system based on the SSC mode indicated by the second information and based on the subscription data of the UE. The determined SSC mode of the PDU session may be the indicated SSC mode or another SSC mode. For example, if the UE requests SSC mode 1 and the UE subscription supports SSC mode 1 and SSC mode 2, the determined SSC mode of the PDU session is 1, and if the UE requests SSC mode 1 and the UE subscription supports SSC mode 2, the determined SSC mode of the PDU session is 2.

[0236] Furthermore, the process of the UE moving from the first communication system to the second communication system in step 204 may have two different cases based on whether the UE is in an idle state or a connected state. These two cases are described separately below. The UE moving from the first communication system to the second communication system in an idle state specifically means that the UE moves to the second communication system by using a reselection process. For example, when the UE detects that the signal of a base station in the first communication system is weakening, the UE initiates a cell search process, and when the UE finds the signal of a base station in the second communication system, it reselects a base station in the second communication system. The UE moving from the first communication system to the second communication system in a connected state specifically means that the UE moves to the second communication system by using a handover process. For example, when a base station receives a measurement report reported by a UE in a first communication system and determines that the UE needs to be handed over to a base station in a second communication system, the base station initiates a handover process in the first communication system, and when the UE receives a handover command sent by the base station in the first communication system, the UE moves from the first communication system to the second communication system.

[0237] Case 1: The UE moves from the first communication system to the second communication system in an idle state. The UE may move from the first communication system to the second communication system in an idle state in the following two ways (I) and (II), which are specifically described as follows:

[0238] (I) The UE generates first EPS bearer status information based on a second condition and sends the first EPS bearer status information to a second core network entity, which then returns a second message. The second message includes the second EPS bearer status information, and the second core network entity is a core network entity, such as an AMF, in the second communication system that is responsible for access and mobility management for the UE. Accordingly, the first condition in step 205 may further include the second EPS bearer status information.

[0239] The second condition includes the correspondence relationship stored by the UE in step 203, specifically, the correspondence relationship between the EBI of the first EPS bearer and the first QoS flow information, or the correspondence relationship between the first EPS bearer and the first QoS flow information.

[0240] Furthermore, the EPS bearer status information is a single phrase, and the "first" in the "first EPS bearer status information" and the "second" in the "second EPS bearer status information" are used to define and distinguish different EPS bearer status information. The first EPS bearer status information is used to identify active EPS bearers belonging to the UE and having corresponding QoS flow information. Specifically, the EPS bearers identified in the first EPS bearer status information are active EPS bearers belonging to the UE and having corresponding QoS flow information and determined by the UE based on a correspondence relationship. The second EPS bearer status information is used to identify active EPS bearers belonging to the UE and having corresponding QoS flow information and determined by a second core network entity. For example, a UE has four active EPS bearers in a first communication system, and the EBIs corresponding to these four EPS bearers are 5, 6, 7, and 8, respectively. The EPS bearers whose EBI is 5 and 7 have corresponding QoS flow information, and the EPS bearers whose EBI is 6 and 8 do not have corresponding QoS flow information. In the first EPS bearer status information reported by the UE, only the EPS bearers whose EBI is 5 and 7 are identified as active, and the other bearers are identified as inactive. Details are shown in Table 2 below. [Table 2]

[0241] Specifically, the UE generates first EPS bearer status information based on the second condition and transmits the first EPS bearer status information to a second core network entity. The second core network entity may receive the first EPS bearer status information, obtain a PDN connection context for the UE from a core network entity MME in the first communication system, and determine second information based on a sixth condition. The sixth condition includes the first EPS bearer status information and the PDN connection context. The second core network entity transmits the second information to the first core network entity, and the first core network entity generates QoS flow information to be used by the UE in the second communication system based on a fifth condition. The QoS flow information includes QoS flow information for the UE and corresponding to active EPS bearers determined by the second core network entity, and the fifth condition includes the second information and a correspondence relationship stored by the first core network entity. The first core network entity may then send third information to the second core network entity, where the third information is the generated bearer identifier of the EPS bearer corresponding to the QoS flow information. As a result, the second core network entity generates second EPS bearer status information based on the seventh condition and transmits the second EPS bearer status information to the UE by using the second message. The seventh condition includes the third information. The QoS flow information may be understood as a set of one or more QoS flow information or a set of information for one or more PDU sessions. When the QoS flow information includes only one QoS flow information or only one PDU session information, it may be understood that the set includes only one QoS flow information or only one PDU session information. This understanding is similar to that in other parts of this specification. Details will not be described again.

[0242] The second information includes an EPS bearer identifier EBI movable to the second communication system, or includes a linked bearer identifier (LBI) and an EPS bearer identifier EBI, or includes a PDN connection context, wherein the PDN connection context includes an EPS bearer context movable to the second communication system. If the second information includes an EPS bearer identifier EBI movable to the second communication system or includes a linked bearer identifier and an EPS bearer identifier, the first core network entity generates QoS flow information based on the EPS bearer identifier EBI and the stored correspondence, or generates second QoS flow information based on the linked bearer identifier, the EPS bearer identifier, and the stored correspondence. If the second information includes a PDN connection context, the first core network entity maps the PDN connection context to the second QoS flow information based on the stored correspondence.

[0243] In this embodiment of the present application, the first core network entity may be the SMF+PGW-C, and the second core network entity may be the AMF. Specifically, as shown in FIG. 5, the UE may send a registration request to the AMF, and the registration request may carry the UE's identifier and first EPS bearer status information. When the AMF receives the registration request, the AMF may obtain an MME serving the UE based on the UE's identifier and request a PDN connection context for the UE from the MME. The AMF performs an authentication and authorization process on the UE, returns a PDN connection context acknowledgement message to the MME, and sends a location update request to the UDM+HSS, and the UDM+HSS returns a response message. Based on the first EPS bearer status information sent by the UE and the PDN connection context obtained from the MME, the AMF obtains a PDN connection and an EPS bearer on the PDN connection that can be moved from the first communication system (e.g., 4G) to the second communication system (e.g., 5G), and obtains a corresponding SMF+PGW-C address. Then, the AMF obtains a linked bearer identifier and a bearer identifier corresponding to the PDN connection movable to the second communication system and sends the linked bearer identifier and the bearer identifier to the SMF+PGW-C, and the SMF+PGW-C generates second QoS flow information based on the stored correspondence and the linked bearer identifier and the bearer identifier. Alternatively, the AMF obtains a PDN connection context movable to the second communication system and sends the PDN connection context to the SMF+PGW-C, and the SMF+PGW-C maps the received PDN connection context to the second QoS flow information based on the stored correspondence. Finally, the SMF+PGW-C sends the generated bearer identifier of the EPS bearer corresponding to the second QoS flow information to the AMF, so that the AMF generates second EPS bearer status information based on the bearer identifier and returns the second EPS bearer status information to the UE by using a registration accept message.

[0244] Accordingly, step 205 specifically includes: the UE determines the QoS flow information to be used by the UE in the second communication system based on the stored correspondence and the second EPS bearer status information.

[0245] Optionally, the process in which the AMF obtains a PDN connection and an EPS bearer on the PDN connection that can be moved from a first communication system (e.g., 4G) to a second communication system (e.g., 5G) and obtains a corresponding SMF+PGW-C address may include: the AMF obtains a PDN connection and an EPS bearer on the PDN connection that can be moved to the second communication system based on an EPS bearer intersection set between the first EPS bearer status information and the bearer context in the PDN connection context, and the AMF may obtain an SMF+PGW-C address based on the PDN connection context.

[0246] Specifically, when the first message is a registration accept message, the N1 Session Management Information (N1 SM Information) parameter includes the first QoS flow information, or when the first message is a PDU Session Modify message, the N1 Session Management Information parameter of the PDU Session Modify message includes the first QoS flow information.

[0247] (II) The UE generates first QoS flow status information based on a third condition and sends the first QoS flow status information to a second core network entity, which then returns a second message. The second message includes the second QoS flow status information, and the second core network entity is a core network entity in the second communication system that is responsible for access and mobility management of the UE. Accordingly, the first condition in step 205 may further include the second QoS flow status information.

[0248] The third condition includes the correspondence relationship stored by the UE in step 203, specifically, the correspondence relationship between the EBI of the first EPS bearer and the first QoS flow information, or the correspondence relationship between the first EPS bearer context and the first QoS flow information, or the correspondence relationship between the first EPS bearer context and the index information of the first QoS flow.

[0249] Furthermore, the term "QoS flow status information" is a single phrase, and the "first" in "first QoS flow status information" and the "second" in "second QoS flow status information" are used to define and distinguish different QoS flow status information. The first QoS flow status information is used to identify QoS flows corresponding to active EPS bearers of the UE. Specifically, the QoS flows identified in the first QoS flow status information are QoS flows corresponding to active EPS bearers and determined by the UE based on a correspondence relationship. The second QoS flow status information is used to identify QoS flows corresponding to active EPS bearers of the UE and determined by a second core network entity. In this specification, a QoS flow corresponding to an active EPS bearer of the UE may be understood as a QoS flow corresponding to an active EPS bearer having a corresponding QoS flow. In other words, an active EPS bearer may be understood as an EPS bearer that is active and has a corresponding QoS flow. This understanding is used in other parts of this specification, and details will not be described again.

[0250] Specifically, the UE generates first QoS flow status information based on the third condition and sends the first QoS flow status information to the second core network entity. The second core network entity receives the first QoS flow status information, obtains a PDN connection context for the UE from a core network entity MME in the first communication system, and sends the first QoS flow status information and the PDN connection context to the first core network entity, so that the first core network entity generates second QoS flow information for the UE in the second communication system based on a fifth condition. The fifth condition includes the first QoS flow status information and the PDN connection context. The first core network entity may then return the second QoS flow information to the second core network entity, so that the second core network entity generates second QoS flow status information, specifically, second information determined by the second core network entity, and returns the second QoS flow status information to the UE by using a second message.

[0251] In this embodiment of the present application, the first core network entity may be the SMF+PGW-C, and the second core network entity may be the AMF. Specifically, as shown in FIG. 6, the UE may send a registration request to the AMF, and the registration request may carry the UE's identifier and first QoS flow status information. When the AMF receives the registration request, the AMF may obtain an MME serving the UE based on the UE's identifier and request a PDN connection context of the UE from the MME. The AMF performs an authentication and authorization process on the UE, returns a PDN connection context acknowledgement message to the MME, and sends a location update request to the UDM+HSS, and the UDM+HSS returns a response message. The AMF learns that the PDN connection can be moved to the second communication system based on the SMF+PGW-C, which is a network element in the PDN connection context and shared by the first communication system (e.g., 4G) and the second communication system (e.g., 5G). The AMF sends the acquired PDN connection context and the first QoS flow status information to the SMF+PGW-C. The SMF+PGW-C maps the PDN connection context to QoS flow information, determines an intersection set between the first QoS flow status information and the QoS flow information acquired through the mapping as second QoS flow information, and may further delete QoS flows not described in the QoS flow information. The SMF+PGW-C then returns the second QoS flow information to the AMF, and the AMF generates second QoS flow status information based on the second QoS flow information and returns the second QoS flow status information to the UE by using a registration accept message.

[0252] Accordingly, step 205 specifically includes: the UE determines, based on the stored correspondence and the second QoS flow status information, the QoS flow information used by the UE in the second communication system.

[0253] It should be noted that in the above-mentioned modes (I) and (II), the first EPS bearer status information and the first QoS flow status information may be collectively referred to as the first status information, and the second EPS bearer status information and the second QoS flow status information may be collectively referred to as the second status information.

[0254] Case 2: A process of moving a UE from a first communication system to a second communication system while the UE is connected may include: the UE receives a handover command sent by a base station in the first communication system, the handover command including a session identifier and a QoS flow identifier. Accordingly, the first condition in step 205 may further include the session identifier and the QoS flow identifier.

[0255] In this embodiment of the present application, the first core network entity may be an SMF+PGW-C, and the second core network entity may be an AMF. Specifically, as shown in Figure 7, when a base station (e.g., a 4G base station) determines in a first communication system that a UE needs to move from the first communication system to a second communication system, the base station sends a handover request to a core network entity MME in the first communication system. When the MME receives the handover request, the MME sends a relocation request to a core network entity AMF in the second communication system, where the relocation request includes the PDN connection context of the UE. The AMF obtains an SMF+PGW-C serving the UE based on the PDN connection context, and sends a Session Management (SM) context request message to the SMF+PGW-C. The request message includes the PDN connection context. Upon receiving the SM context request message, the SMF+PGW-C determines PDU session information (which may also be a PDU session context) in the second communication system and corresponding to the PDN connection context based on the PDN connection context and the stored correspondence. Then, the SMF+PGW-C sends an N4 session creation request to the UPF+PGW-U and an SM context response message to the AMF. The response message includes the PDU session information. The AMF sends a handover request to the base station in the second communication system, where the handover request includes the PDU session information. The base station returns radio resource information allocated to the UE to the AMF in the second communication system. The AMF sends an SM context update message to the SMF+PGW-C, where the update message is used to create a tunnel between the UPF+PGW-U and the base station in the second communication system. The AMF sends a location update response message to the MME, where the response message includes radio resource information allocated to the UE by the base station in the second communication system.The MME sends a forwarding tunnel creation request to the SGW, and sends a handover command to a base station in the first communication system, the handover command including radio resource information allocated to the UE. The base station sends the handover command to the UE in the first communication system. The handover command includes the radio resource information allocated to the UE, and the radio resource information includes a session identifier and a QoS flow identifier.

[0256] Specifically, a process in which the SMF sends an SM context request message to the SMF+PGW-C and the SMF+PGW-C determines PDU session information in the second communication system may include: the AMF obtains a PDN connection and an EPS bearer on the PDN connection that are movable from the first communication system to the second communication system, and obtains the corresponding SMF+PGW-C address, linked bearer identifier, and bearer identifier; the AMF sends the linked bearer identifier and bearer identifier to the SMF+PGW-C; and the SMF+PGW-C determines the linked bearer identifier and bearer identifier. Determine PDU session information based on the child and bearer identifiers and the stored correspondence, or the AMF obtains a PDN connection that can be moved from the first communication system to the second communication system and an EPS bearer on the PDN connection, and obtains a corresponding SMF+PGW-C address and a PDN connection context that includes an EPS bearer context that can be moved to the second communication system, the AMF sends the PDN connection context to the SMF+PGW-C, and the SMF+PGW-C determines PDU session information based on the PDN connection context and the stored correspondence.

[0257] Accordingly, step 205 specifically includes: the UE determines, based on the first QoS flow information, the session identifier, and the QoS flow identifier, the QoS flow information used by the UE in the second communication system.

[0258] Furthermore, after step 203 and before step 204, specifically after the UE receives the first message and before the UE moves from the first communication system to the second communication system, the method further includes step 203a and step 203b.

[0259] Step 203a: The UE receives a fourth message, where the fourth message is used to delete the first EPS bearer.

[0260] The fourth message may be sent by the MME to the UE in the first communication system shown in Figure 1. Specifically, the MME sends the fourth message to the UE, instructing the UE to delete the first EPS bearer.

[0261] Step 203b: The UE deletes the first EPS bearer and the first QoS flow information corresponding to the first EPS bearer.

[0262] Specifically, when the UE deletes the first QoS flow information corresponding to the first EPS bearer, if the UE has stored the first QoS flow information in step 203, the UE deletes the stored first QoS flow information; if the UE has stored a correspondence between the bearer identifier of the first EPS bearer and the first QoS flow information, or a correspondence between the first EPS bearer context and the first QoS flow information, or a correspondence between the first EPS bearer context and the index information of the first QoS flow in step 203, the UE deletes the stored correspondence.

[0263]

[0044] Referring to Figure 8, after the UE determines the QoS flow information to be used by the UE in the second communication system based on the first condition, the method may further include step 205a. Figure 8 is described based on Figure 4 merely as an example, and the method for moving between communication systems shown in Figure 5 is also applicable.

[0264] Step 205a: The UE deletes a second EPS bearer context, where the second EPS bearer is an EPS bearer related to the UE and has no corresponding QoS flow information. In the method for moving between communication systems provided in this embodiment of the present application, when the UE establishes a PDN connection, the UE instructs a first core network entity to determine first QoS flow information, which belongs to the second communication system and corresponds to the first EPS bearer of the UE in the first communication system, by using first information. Then, the first core network entity determines and stores the first QoS flow information, and sends the first QoS flow information to the UE by using a first message. When the UE moves from the first communication system to the second communication system, the UE and the first core network entity may determine QoS flow information to be used by the UE in the second communication system based on the first QoS flow information, in which case, when the UE moves from the first communication system to the second communication system, a mapping between the first EPS bearer and the first QoS flow information is performed and active bearers are aligned, thereby ensuring a seamless transition of the UE to the second communication system.

[0265] 9 is a flowchart of a method for moving between communication systems according to an embodiment of the present application. Referring to FIG. 9, the method is applied to the communication system shown in FIG. 1 and is used to move a UE from a first communication system to a second communication system. The method may include the following steps:

[0266] Step 301: The UE establishes a first EPS bearer in a first communication system and moves from the first communication system to a second communication system.

[0267] A PDN connection in the first communication system corresponds to a PDU session in the second communication system. One PDN connection may include multiple EPS bearers, and one PDU session may include multiple QoS flows. A UE may establish multiple PDN connections in the first communication system, and among the multiple PDN connections, one or more PDN connections may be movable to the second communication system. A PDN connection movable to a second communication system means that the PGW used by the PDN connection is an SMF+PGW-C integrated in 4G and 5G, or that when the UE moves from the first communication system to the second communication system, a PDU session corresponding to the PDN connection can be established in the second communication system, and the PDN connection has the same IP address as the PDU session, or that the PGW used by the PDN connection is an SMF+PGW-C integrated in 4G and 5G, and that when the UE moves from the first communication system to the second communication system, a PDU session corresponding to the PDN connection can be established in the second communication system, and the PDN connection has the same IP address as the PDU session. The first EPS bearer is an EPS bearer included in the PDN connection established by the UE in the first communication system, and may be one EPS bearer or a group of EPS bearers.

[0268] In this embodiment of the present application, the first communication system may be a 4G communication system and the second communication system may be a 5G communication system, so that the UE may establish a first EPS bearer in the 4G communication system and move from the 4G communication system to the 5G communication system after establishing the first EPS bearer.

[0269] Step 302: The UE receives a first message, where the first message includes first QoS flow information that is of a second communication system and corresponds to a first EPS bearer.

[0270] The first QoS flow corresponds to the first EPS bearer and may include one QoS flow or a group of QoS flows. The first QoS flow information is information obtained after the first EPS bearer is mapped to a QoS flow in the second communication system, and includes QoS information of the QoS flow, for example, the mapping is performed based on a predetermined mapping rule. Alternatively, the first QoS flow information is generated based on the first EPS bearer. The first QoS flow information is a combination of one or more of the following information: a QoS flow identifier (QFI) and a QoS flow template. The QoS information may further include one or more of the following information: a 5QI, an ARP, a GFBR, a MFBR, and notification control related to QoS. Not all EPS bearers on a UE are transferable to the second communication system. For example, non-GBR EPS bearers cannot be transferred to the second communication system. Alternatively, when a PDN connection cannot be moved to the second communication system, any EPS bearers corresponding to that PDN connection cannot be moved to the second communication system either, and EPS bearers that cannot be moved to the second communication system do not have corresponding QoS flow information.

[0271] In this embodiment of the present application, the first QoS flow information may include one or more QoS rules. When the first EPS bearer is a default bearer, the first QoS flow information includes one or more of the following information: a session aggregate maximum bit rate (session AMBR), an SSC mode, a PDU session identifier, and a QoS rule. The QoS rule may be one or more QoS rules. Specifically, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a precedence, or a packet filter. Alternatively, the QoS rule includes one or more of the following information: a QoS rule identifier, a QoS flow identifier, a precedence, and a packet filter identifier. The packet filter includes a packet filter attribute and a packet filter identifier. The first QoS flow information may further include a combination of one or more of the following information: 5QI, ARP, GFBR, MFBR, and notification control for the QoS flow. It may be understood that the default bearer of the UE is configured in a process in which the UE establishes a PDN connection in the first communication system. In other words, configuring a default bearer for the UE may be understood as establishing a PDN connection for the UE. Specifically, the UE may request to establish a PDN connection by using an attach request or a PDN connectivity request. In the process of establishing a PDN connection for the UE in the first communication system, information about a PDU session belonging to the second communication system and corresponding to the PDN connection is transmitted to the UE by using a request message used to configure the default bearer. The information about the PDU session includes one or more of a session aggregate maximum bit rate (session AMBR), an SSC mode, and a PDU session identifier.

[0272] For example, a method used by the SMF+PGW-C to determine first QoS flow information in a 5G communication system may be as follows: the SMF+PGW-C generates a 5G QoS rule based on a traffic flow template (TFT) of an EPS context. The method specifically includes generating the QoS rule based on one or more policy and charging control (PCC) rules used to generate the TFT of the EPS bearer. The priority of each PCC is set to the priority of the QoS rule, and one or more packet filters of the PCC are set to the packet filter of the QoS rule. Furthermore, the SMF+PGW-C may further assign a QoS rule identifier to the QoS rule. For example, the SMF+PGW-C may further set the QCI of the EPS bearer to 5G 5QI, the GBR of the EPS bearer to 5G GFBR, the MBR of the EPS bearer to 5G MFBR, and the EBI of the default bearer of the PDN connection to a 5G PDU session identifier.

[0273] The method may further include the UE acquiring a first QoS flow identifier (QFI), where the first QoS flow identifier is acquired after the UE adds a specific value to the first EPS bearer identifier (EBI), or the first QoS flow identifier is acquired after the UE adds a specific field to the first EPS bearer identifier.

[0274] For example, the QFI is obtained after a specific value is added to the EBI, for example, the specific value is 10. If the EBI is 5, the QFI is 15, and if the EBI is 6, the QFI is 16. As another example, the QFI is obtained after a specific field is added to the EBI, for example, the specific field is 1 byte. If the EBI is 1 byte, the QFI is obtained after adding 1 byte after the EBI. If 1 byte of the EBI is 00000101, the QFI is 2 bytes obtained after adding 1 byte: 00000101 00000001.

[0275] It should be noted that the specific values and the specific numerical values of the specific fields may be set based on requirements, which are not specifically limited in this embodiment of the present invention.

[0276] Furthermore, the first message may be sent to the UE by a second core network entity. Specifically, before the second core network entity sends the first message, the second core network entity may determine first QoS flow information and send the first QoS flow information to the UE by using the first message, so that the UE receives the first message sent by the second core network entity, including the first QoS flow information that belongs to the second communication system and corresponds to the first EPS bearer. The second core network entity may be a core network entity in the second communication system that is responsible for access and mobility management of the UE, and the second core network entity may be an AMF in the second communication system shown in FIG. 1.

[0277] In this embodiment of the present application, the first message may be a Registration Accept message, and an N1 Session Management Information (N1 SM Information) parameter of the Registration Accept message includes the first QoS flow information; or the first message is a PDU Session Modification message, and an N1 Session Management Information parameter of the PDU Session Modification message includes the first QoS flow information. Alternatively, the first message is a Handover Command message, and the Handover Command message includes the first QoS flow information. QoS flow information in a 5G communication system may also be referred to as a 5G QoS parameter.

[0278] Specifically, when the first message is a handover command message, a target to source transparent container of the handover command message includes the first QoS flow information, and an access stratum of the UE may obtain the first QoS flow information from the target to source transparent container and send the first QoS flow information to a non-access stratum of the UE.

[0279] The first message may further include information about a first EPS bearer corresponding to the first QoS flow information, and the information about the first EPS bearer may include a bearer identifier of the first EPS bearer. Specifically, the second core network entity may add the information about the first EPS bearer and the first QoS flow information to the first message and transmit the information about the first EPS bearer and the first QoS flow information to the UE by using the first message.

[0280] Step 303: The UE determines QoS flow information to be used by the UE in the second communication system based on a first condition, where the first condition includes the first QoS flow information.

[0281] The QoS flow information used by the UE in the second communication system may be QoS flow information corresponding to one or more PDU sessions of the UE, or may be information about one or more PDU sessions of the UE, which is not particularly limited in this embodiment of the present application.

[0282] Specifically, the UE determines QoS flow information that can be used by the UE in the second communication system based on the first QoS flow information included in the first condition, thereby performing mapping between the UE's EPS bearer in the first communication system and the QoS flow in the second communication system, and seamlessly transitioning the UE from the first communication system to the second communication system.

[0283] It should be noted that there may be no order between step 303 and the process of the UE moving from the first communication system to the second communication system in step 301. Specifically, the UE may first move from the first communication system to the second communication system and then determine the QoS flow information used in the second communication system, or the UE may first determine the QoS flow information used in the second communication system and then move from the first communication system to the second communication system, or the UE may determine the QoS flow information used in the second communication system in the process of moving from the first communication system to the second communication system. This is not particularly limited in this embodiment of the present application. In the example shown in FIG. 9, the process of the UE moving from the first communication system to the second communication system is before step 303.

[0284] Furthermore, the process of the UE moving from the first communication system to the second communication system in step 301 may have two different cases based on whether the UE is in an idle state or a connected state. These two cases are described separately below. The UE moving from the first communication system to the second communication system in an idle state specifically means that the UE moves to the second communication system by using a reselection process. For example, when the UE detects that the signal of a base station in the first communication system is weakening, the UE initiates a cell search process, and when the UE finds the signal of a base station in the second communication system, it reselects a base station in the second communication system. The UE moving from the first communication system to the second communication system in a connected state specifically means that the UE moves to the second communication system by using a handover process. For example, when a base station receives a measurement report reported by a UE in a first communication system and determines that the UE needs to be handed over to a base station in a second communication system, the base station initiates a handover process in the first communication system, and when the UE receives a handover command sent by the base station in the first communication system, the UE moves from the first communication system to the second communication system.

[0285] Case 1: The UE moves from the first communication system to the second communication system in an idle state. The UE may move from the first communication system to the second communication system in an idle state in the following two ways (1) and (2), which are specifically described as follows:

[0286] (1) The UE sends first EPS bearer status information to a second core network entity, where the first EPS bearer status information is used to identify an active EPS bearer of the UE, and the second core network entity is a core network entity in a second communication system and responsible for access and mobility management of the UE.

[0287] The EPS bearer status information is a single phrase, and the "first" in the "first EPS bearer status information" and the "second" in the "second EPS bearer status information" are used to define and distinguish different EPS bearer status information. The first EPS bearer status information is used to identify active EPS bearers. Specifically, the EPS bearers identified in the first EPS bearer status information are active EPS bearers determined by the UE. For example, a UE has four active EPS bearers in a first communication system, and the EBIs corresponding to these four EPS bearers are 5, 6, 7, and 8, respectively. The EPS bearers with EBIs 5 and 7 have corresponding QoS flow information, while the EPS bearers with EBIs 6 and 8 do not have corresponding QoS flow information. In the first EPS bearer status information reported by the UE, only the EPS bearers with EBIs 5 and 7 are identified as active, and the other bearers are identified as inactive. Details are shown in Table 2 above.

[0288] Specifically, the UE may determine a first EPS bearer status based on the active EPS bearers and send the first EPS bearer status to a second core network entity. The second core network entity may receive the first EPS bearer status information, obtain a PDN connection context including all PDN connections of the UE from a core network entity MME in the first communication system, and determine second information based on the first EPS bearer status information and the PDN connection context to obtain PDN connection context corresponding to EPS bearers movable to the second communication system. The second information includes EPS bearers movable to the second communication system. The second core network entity sends the obtained PDN connection context to the first core network entity, which then generates QoS flow information to be used by the UE in the second communication system. The QoS flow information includes QoS flow information corresponding to the active EPS bearers of the UE and determined by the first core network entity. The first core network entity may then transmit the second QoS flow information to the second core network entity, which then transmits the second QoS flow information to the UE. The QoS flow information may be understood as a set of one or more QoS flow information, or as a set of information for one or more PDU sessions. When the QoS flow information includes only one QoS flow information or only one PDU session information, it may be understood that the set includes only one QoS flow information or only one PDU session information. The same understanding is applied elsewhere in this specification. Details will not be described again.

[0289] In this embodiment of the present application, the first core network entity may be the SMF+PGW-C, and the second core network entity may be the AMF. Specifically, as shown in FIG. 10, the UE may send a registration request to the AMF, and the registration request may carry the UE's identifier and first EPS bearer status information. When the AMF receives the registration request, the AMF may obtain an MME serving the UE based on the UE's identifier and request a PDN connection context for the UE from the MME. The AMF performs an authentication and authorization process on the UE, returns a PDN connection context acknowledgement message to the MME, and sends a location update request to the UDM+HSS, and the UDM+HSS returns a response message. Based on the first EPS bearer status information sent by the UE and the PDN connection context obtained from the MME, the AMF obtains a PDN connection and EPS bearers on the PDN connection that can be moved from the first communication system (e.g., 4G) to the second communication system (e.g., 5G), and obtains the corresponding SMF+PGW-C address and the corresponding PDN connection context. Then, the AMF obtains a PDN connection context movable to the second communication system and sends the PDN connection context to the SMF+PGW-C. The SMF+PGW-C generates second QoS flow information based on the received PDN connection context. Finally, the SMF+PGW-C sends the second QoS flow information to the AMF, which then returns the second QoS flow information to the UE by using a registration accept message. Furthermore, the UE may store the second QoS flow information and delete EPS bearers that are in the first EPS bearer and do not have corresponding QoS flows.

[0290] Accordingly, step 303 specifically includes: the UE determines, based on the first QoS flow information and the second QoS flow information, the QoS flow information used by the UE in the second communication system.

[0291] Optionally, the process in which the AMF obtains a PDN connection and an EPS bearer on the PDN connection that can be moved from a first communication system (e.g., 4G) to a second communication system (e.g., 5G) and obtains a corresponding SMF+PGW-C address may include: the AMF obtains a PDN connection and an EPS bearer on the PDN connection that can be moved to the second communication system based on an EPS bearer intersection set between the first EPS bearer status information and the bearer context in the PDN connection context, and the AMF obtains an SMF+PGW-C address based on the PDN connection context that can be moved to the second communication system.

[0292] (2) The UE generates first QoS flow status information based on a second condition including the UE's active EPS bearers, and the UE transmits the first QoS flow status information to a second core network entity.

[0293] The QoS flow status information is a single phrase, and the "first" in the "first QoS flow status information" and the "second" in the "second QoS flow status information" below are used to define and distinguish different QoS flow status information. The first QoS flow status information is used to identify QoS flows corresponding to active EPS bearers of the UE. Specifically, the QoS flows identified in the first QoS flow status information are QoS flows corresponding to active EPS bearers and determined by the UE based on a correspondence relationship. The second QoS flow status information is used to identify QoS flows corresponding to active EPS bearers of the UE and determined by a second core network entity.

[0294] Specifically, the UE generates first QoS flow status information based on the UE's active EPS bearers and sends the first QoS flow status information to a second core network entity. The second core network entity receives the first QoS flow status information, obtains a PDN connection context for the UE from a core network entity MME in the first communication system, and sends the first QoS flow status information and the PDN connection context to the first core network entity, so that the first core network entity generates second QoS flow information for the UE in the second communication system based on the first QoS flow status information and the PDN connection context. The first core network entity may then return the second QoS flow information to the second core network entity, so that the second core network entity sends the second QoS flow information to the UE by using a registration accept message.

[0295] In this embodiment of the present application, the first core network entity may be the SMF+PGW-C, and the second core network entity may be the AMF. Specifically, as shown in FIG. 11 , the UE may send a registration request to the AMF, and the registration request may carry the UE's identifier and first QoS flow status information. When the AMF receives the registration request, the AMF may obtain an MME serving the UE based on the UE's identifier and request a PDN connection context of the UE from the MME. The AMF performs an authentication and authorization process on the UE, returns a PDN connection context acknowledgement message to the MME, and sends a location update request to the UDM+HSS, and the UDM+HSS returns a response message. The AMF learns that the PDN connection can be moved to the second communication system based on the SMF+PGW-C, which is a network element in the PDN connection context and shared by the first communication system (e.g., 4G) and the second communication system (e.g., 5G). The AMF sends the acquired PDN connection context and first QoS flow status information to the SMF+PGW-C. The SMF+PGW-C maps the PDN connection context to QoS flow information, determines an intersection set between the first QoS flow status information acquired through the mapping and the QoS flow information as second QoS flow information, and may further delete QoS flows not described in the QoS flow information. The SMF+PGW-C then returns the second QoS flow information to the AMF, and the AMF generates second QoS flow status information based on the second QoS flow information and returns the second QoS flow status information to the UE by using a registration accept message. Furthermore, the UE may store the second QoS flow information and delete EPS bearers that are in the first EPS bearer and do not have corresponding QoS flows.

[0296] Accordingly, step 303 specifically includes: the UE determines, based on the first QoS flow information and the second QoS flow information, the QoS flow information used by the UE in the second communication system.

[0297] Case 2: A process of moving from a first communication system to a second communication system while the UE is connected may include: the UE receives a handover command sent by a base station in the first communication system, where the handover command includes a session identifier and a QoS flow identifier.

[0298] In this embodiment of the present application, the first core network entity may be an SMF+PGW-C, and the second core network entity may be an AMF. Specifically, as shown in Figure 12, when a base station (e.g., E-UTRAN) determines in a first communication system that a UE needs to move from the first communication system to a second communication system, the base station sends a handover request to a core network entity MME in the first communication system. When the MME receives the handover request, the MME sends a relocation request to a core network entity AMF in the second communication system, where the relocation request includes the PDN connection context of the UE. The AMF obtains an SMF+PGW-C serving the UE based on the PDN connection context and sends a Session Management (SM) context request message to the SMF+PGW-C. The request message includes the PDN connection context. Upon receiving the SM context request message, the SMF+PGW-C determines a PDU session context in the second communication system that corresponds to the PDN connection context based on the PDN connection context. The SMF+PGW-C then sends an N4 session creation request to the UPF+PGW-U and an SM context response message to the AMF. The response message includes PDU session information. The AMF then sends a handover request to the base station in the second communication system, where the handover request includes the PDU session information. The base station returns radio resource information allocated to the UE in the second communication system to the AMF. The AMF then sends an SM context update message to the SMF+PGW-C, where the update message is used to create a tunnel between the UPF+PGW-U and the base station in the second communication system. The AMF then sends a location update response message to the MME, where the response message includes the PDU session context and radio resource information allocated to the UE by the base station in the second communication system.The MME sends a forwarding tunnel creation request to the SGW, and sends a handover command to a base station in the first communication system, the handover command including a PDU session context and radio resource information allocated to the UE. The base station sends the handover command to the UE in the first communication system. The handover command includes the PDU session context and the radio resource information allocated to the UE, and the radio resource information includes a session identifier and a QoS flow identifier.

[0299] Optionally, the process of the AMF sending the PDU session context to the UE may further be as follows: the AMF sends the PDU session context to a base station in the second communication system, and the base station encapsulates the PDU session context in a target to source transparent container in the second communication system and sends the PDU session context to the AMF. Then, the AMF sends the PDU session context to the UE by using the MME and the base station in the first communication system. The process of the AMF allocating radio resource information to the UE is consistent with the above description.

[0300] Specifically, a process in which the SMF sends an SM context request message to the SMF+PGW-C and the SMF+PGW-C determines PDU session information in the second communication system may include: the AMF obtains a PDN connection and an EPS bearer on the PDN connection that are movable from the first communication system to the second communication system, and obtains the corresponding SMF+PGW-C address, linked bearer identifier, and bearer identifier; the AMF sends the linked bearer identifier and bearer identifier to the SMF+PGW-C; and the SMF+PGW-C determines the linked bearer identifier and bearer identifier. Determine PDU session information based on the child and bearer identifiers and the stored correspondence, or the AMF obtains a PDN connection that can be moved from the first communication system to the second communication system and an EPS bearer on the PDN connection, and obtains a corresponding SMF+PGW-C address and a PDN connection context that includes an EPS bearer context that can be moved to the second communication system, the AMF sends the PDN connection context to the SMF+PGW-C, and the SMF+PGW-C determines PDU session information based on the PDN connection context and the stored correspondence.

[0301] Accordingly, step 303 specifically includes: the UE determines, based on the first QoS flow information, the session identifier, and the QoS flow identifier, the QoS flow information used by the UE in the second communication system.

[0302] Referring to FIG. 13, after step 303, the method may further include step 304.

[0303] Step 304: The UE deletes a second EPS bearer context, where the second EPS bearer is an EPS bearer not included in the first message, or the second EPS bearer is an EPS bearer belonging to the UE and does not have corresponding QoS flow information.

[0304] In a method for moving between communication systems provided in this embodiment of the present application, a UE establishes a first EPS bearer in a first communication system, moves from the first communication system to a second communication system, receives first QoS flow information corresponding to the first EPS bearer and sent by a second core network entity, and determines QoS flow information to be used by the UE in the second communication system based on a first condition including the first QoS flow information, wherein when the UE moves from the first communication system to the second communication system, a mapping between the first EPS bearer and the first QoS flow information is performed and active bearers are aligned, thereby ensuring a seamless transition of the UE to the second communication system.

[0305] The solutions provided in the embodiments of the present application are described mainly in terms of interactions between network elements. It may be understood that, to implement the above-described functions, each network element, such as a user equipment (UE), a first core network device, or a second core network device, includes a corresponding hardware structure and / or software modules used to perform these functions. Those skilled in the art can easily recognize that the network elements and algorithm steps in the examples described with reference to the embodiments disclosed herein may be implemented in the form of hardware or a combination of hardware and computer software in the present application. Whether a function is implemented by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementations are not considered to depart from the scope of the present application.

[0306] In this embodiment of the present invention, the user equipment, the first core network device, and the second core network device may be divided into functional modules based on the above-mentioned method examples. For example, each functional module may be obtained through division into individual functions, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that the module division in the embodiment of the present application is an example and is merely a logical functional division, and other division styles may be used in actual implementation.

[0307] When each functional module is obtained through the division into functions, Figure 14 is a possible schematic structural diagram of a user equipment involved in the above-mentioned embodiments. The user equipment 300 includes a receiving unit 301, a storing unit 302, a mobile unit 303, and a determining unit 304. The receiving unit 301 is configured to perform the step of receiving first QoS flow information of Figure 3, Figure 4, or Figure 8. The storing unit 302 is configured to perform the step of storing the first QoS flow information of Figure 3, Figure 4, or Figure 8. The mobile unit 303 is configured to perform step 204 of Figure 3, Figure 4, or Figure 8. The determining unit 304 is configured to perform step 205 of Figure 3, Figure 4, or Figure 8. The user equipment 300 further includes a sending unit 305 and / or a deleting unit 306. The sending unit 305 is configured to perform step 200a of Figure 4 or Figure 8 and step 201a of Figure 4A. The deletion unit 306 is configured to perform step 205a of Fig. 8. All relevant contents of the steps involved in the above-mentioned method embodiments may be cited in the functional descriptions of the corresponding functional modules, and will not be described in detail again here.

[0308] In a hardware implementation, the mobile unit 303, the determining unit 304, and the deleting unit 306 may be processors, the receiving unit 301 may be a receiver, and the sending unit 305 may be a transmitter. The transmitter and the receiver may form a communication interface.

[0309] FIG. 15 is a schematic logical structural diagram of a possible user equipment 310 involved in the above-described embodiment according to an embodiment of the present application. The user equipment 310 includes a processor 312, a communication interface 313, a memory 311, and a bus 314. The processor 312, the communication interface 313, and the memory 311 are connected to each other using the bus 314. In this embodiment of the present invention, the processor 312 is configured to control and manage the operation of the user equipment 310. For example, the processor 312 is configured to perform steps 203 and 204 of FIG. 3, FIG. 4, or FIG. 8, step 205a of FIG. 8, and / or other processes of the techniques described herein. The communication interface 313 is configured to support communication for the user equipment 310. The memory 311 is configured to store program codes and data for the user equipment 310.

[0310] The processor 312 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 312 may implement or execute various illustrative logic blocks, modules, and circuits described with reference to the subject matter disclosed herein. Alternatively, the processor may be a combination for performing computational functions, such as one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 314 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. Buses may be categorized as address buses, data buses, control buses, etc. For ease of illustration, FIG. 15 uses only one thick line to represent a bus, but this does not imply that there is only one bus or one type of bus.

[0311] When each functional module is obtained through division into functions, Figure 16 is a possible schematic structural diagram of a first core network device involved in the above-mentioned embodiment. The first core network device 400 includes a determining unit 401, a sending unit 402, and a storing unit 403. The determining unit 401 is configured to perform the step of determining first QoS flow information in step 201 of Figure 3 or Figure 4, or the step of determining first QoS flow information in step 200b and step 201 of Figure 8. The sending unit 402 is configured to perform step 202 of Figure 3, Figure 4, or Figure 8. The storing unit 403 is configured to perform the step of storing the first QoS flow information in step 201 of Figure 3, Figure 4, or Figure 8. The first core network device 400 further includes a receiving unit 404, which is configured to perform the step of receiving the first information transmitted by the UE in Fig. 4, step 201b in Fig. 4A, and / or other processes of the techniques described herein. All relevant contents of the steps involved in the above-mentioned method embodiments may be referred to in the functional descriptions of the corresponding functional modules, and will not be described in detail again here.

[0312] In a hardware implementation, the determining unit 401 may be a processor, the sending unit 402 may be a transmitter, and the receiving unit 404 may be a receiver. The receiver and the transmitter may form a communication interface.

[0313] FIG. 17 is a schematic logical structural diagram of a first core network device 410 involved in the above-described embodiment of the present application. The first core network device 410 includes a processor 412, a communication interface 413, a memory 411, and a bus 414. The processor 412, the communication interface 413, and the memory 411 are connected to each other using the bus 414. In this embodiment of the present invention, the processor 412 is configured to control and manage the operation of the first core network device 410. For example, the processor 412 is configured to perform steps 201 and 206 of FIG. 3 or 8, steps 200b, 201, and 206 of FIG. 4, and / or other processes of the techniques described herein. The communication interface 413 is configured to support communication of the first core network device 410. The memory 411 is configured to store program codes and data for the first core network device 410.

[0314] The processor 412 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 412 may implement or execute various illustrative logic blocks, modules, and circuits described with reference to the disclosed subject matter in this application. Alternatively, the processor may be a combination for performing computational functions, such as one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 414 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. Buses may be categorized as address buses, data buses, control buses, etc. For ease of illustration, FIG. 17 uses only one thick line to represent a bus, but this does not imply that there is only one bus or one type of bus.

[0315] When each functional module is obtained through division into respective functions, Figure 18 is a possible schematic structural diagram of a second core network device involved in the above-mentioned embodiment. The second core network device 500 includes an obtaining unit 501, a determining unit 502, and a sending unit 503. The obtaining unit 501 is configured to perform a step of obtaining first status information and a PDN connection context, and a step of receiving third information sent by the first core network entity. The determining unit 502 is configured to perform a step of determining second information and / or another process of the technology described herein. The sending unit 503 is configured to perform a step of sending the second information and a step of sending a second message to the UE. All relevant contents of the steps involved in the above-mentioned method embodiments may be cited in the functional descriptions of the corresponding functional modules, and will not be described in detail again here.

[0316] In a hardware implementation, the determining unit 502 may be a processor, the obtaining unit 501 may be a receiver, and the receiving unit 503 may be a transmitter. The transmitter and the receiver may form a communication interface.

[0317] 19 is a schematic logical structural diagram of a possible second core network device 510 involved in the above-described embodiment of the present application. The second core network device 510 includes a processor 512, a communication interface 513, a memory 511, and a bus 514. The processor 512, the communication interface 513, and the memory 511 are connected to each other using the bus 514. In this embodiment of the present application, the processor 512 is configured to control and manage the operation of the second core network device 510. For example, the processor 512 is configured to perform a step of determining the second information and / or another process of the techniques described herein. The communication interface 513 is configured to support communication of the second core network device 510. The memory 511 is configured to store program codes and data for the second core network device 510.

[0318] The processor 512 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 512 may implement or execute various illustrative logic blocks, modules, and circuits described with reference to the disclosed subject matter in this application. Alternatively, the processor may be a combination for performing computational functions, such as one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 514 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. Buses may be categorized as address buses, data buses, control buses, etc. For ease of illustration, FIG. 19 uses only one thick line to represent a bus, but this does not imply that there is only one bus or one type of bus.

[0319] When each functional module is obtained through the division into functions, Figure 20 is a possible schematic structural diagram of a user equipment involved in the above-mentioned embodiments. The user equipment 600 includes a setting unit 601, a mobile unit 602, a receiving unit 603, and a determining unit 604. The setting unit 601 is configured to perform the step of setting up an EPS bearer in a first communication system in step 301 of Figure 9 or Figure 13. The mobile unit 602 is configured to perform the step of moving from the first communication system to a second communication system in step 301 of Figure 9 or Figure 13. The receiving unit 603 is configured to perform step 302 of Figure 9 or Figure 13. The determining unit 604 is configured to perform step 303 of Figure 9 or Figure 13. The user equipment 600 further includes a sending unit 605 and / or a deleting unit 606. The sending unit 605 is configured to perform a step of sending the first EPS bearer status information to the second core network device or a step of sending the first QoS flow status information to the second core network device. The deleting unit 606 is configured to perform step 304 in Fig. 13. All relevant contents of the steps involved in the above-mentioned method embodiments may be cited in the functional descriptions of the corresponding functional modules, and will not be described in detail again here.

[0320] In a hardware implementation, the determining unit 604 and the deleting unit 606 may be a processor, the receiving unit 603 may be a receiver, and the sending unit 605 may be a transmitter. The transmitter and the receiver may form a communication interface.

[0321] 21 is a schematic diagram of a possible logical structure of user equipment 610 involved in the above-described embodiment according to an embodiment of the present application. User equipment 610 includes a processor 612, a communication interface 613, a memory 611, and a bus 614. Processor 612, communication interface 613, and memory 611 are connected to each other using bus 614. In this embodiment of the present application, processor 612 is configured to control and manage the operation of user equipment 610. For example, processor 612 is configured to perform step 303 of FIG. 9 or FIG. 13, step 304 of FIG. 13, and / or other processes of the techniques described herein. Communication interface 613 is configured to support communication for user equipment 610. Memory 611 is configured to store program codes and data for user equipment 610.

[0322] The processor 612 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 612 may implement or execute various illustrative logic blocks, modules, and circuits described with reference to the disclosed subject matter in this application. Alternatively, the processor may be a combination for performing computational functions, such as one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 614 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. Buses may be categorized as address buses, data buses, control buses, etc. For ease of illustration, FIG. 21 uses only one thick line to represent a bus, but this does not imply that there is only one bus or one type of bus.

[0323] When each functional module is obtained through division into functions, FIG. 22 is a possible schematic structural diagram of a first core network device involved in the above-mentioned embodiment. The first core network device 700 includes a receiving unit 701 and a determining unit 702. The receiving unit 701 is configured to perform a step of receiving first information transmitted by a second core network device or a step of receiving second information transmitted by the second core network device when a UE moves from a first communication system to a second communication system. The determining unit is configured to determine QoS flow status information used by the UE in the second communication system and / or another process of the technology described herein. The first core network device 700 further includes a deleting unit 703, which is configured to delete a QoS flow that is in the QoS flow corresponding to an EPS bearer of a PDN connection but is not in the QoS flow status information. All relevant contents of the steps involved in the above-mentioned method embodiments may be cited in the functional descriptions of the corresponding functional modules and will not be described in detail again here.

[0324] In a hardware implementation, the determining unit 702 may be a processor, and the receiving unit 701 may be a receiver. The receiver and the transmitter may form a communication interface.

[0325] 23 is a schematic logical structural diagram of a first core network device 710 related to the above-described embodiment of the present application. The first core network device 710 includes a processor 712, a communication interface 713, a memory 711, and a bus 714. The processor 712, the communication interface 713, and the memory 711 are connected to each other using the bus 714. In this embodiment of the present application, the processor 712 is configured to control and manage the operation of the first core network device 710. For example, the processor 712 is configured to determine QoS flow status information used by a UE in the second communication system and / or perform other processes of the techniques described herein. The communication interface 713 is configured to support communication of the first core network device 710. The memory 711 is configured to store program codes and data for the first core network device 710.

[0326] The processor 712 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 712 may implement or execute various illustrative logic blocks, modules, and circuits described with reference to the disclosed subject matter in this application. Alternatively, the processor may be a combination for performing computational functions, such as a combination of one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 714 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. Buses may be categorized as address buses, data buses, control buses, etc. For ease of illustration, FIG. 23 uses only one thick line to represent a bus, but this does not imply that there is only one bus or one type of bus.

[0327] When each functional module is obtained through division into functions, Figure 24 is a possible schematic structural diagram of a second core network device involved in the above-mentioned embodiment. The second core network device 800 includes an acquiring unit 801 and a sending unit 802. The acquiring unit 801 is configured to acquire first QoS flow information and / or perform another process described herein, and the sending unit 802 is configured to transmit the first QoS flow information to the UE and / or perform another process described herein. The second core network device 800 further includes a determining unit 803 configured to determine third information based on the first EPS bearer status information and the PDN connection context and / or perform another process described herein. All relevant contents of the steps involved in the above-mentioned method embodiments may be cited in the functional descriptions of the corresponding functional modules and will not be described in detail again here.

[0328] In a hardware implementation, the determining unit 803 may be a processor, the obtaining unit 801 may be a receiver, and the receiving unit 802 may be a transmitter. The transmitter and the receiver may form a communication interface.

[0329] FIG. 25 is a schematic logical structural diagram of a second core network device 810 involved in the above-described embodiment of the present application. The second core network device 810 includes a processor 812, a communication interface 813, a memory 811, and a bus 814. The processor 812, the communication interface 813, and the memory 811 are connected to each other using the bus 814. In this embodiment of the present application, the processor 812 is configured to control and manage the operation of the second core network device 810. For example, the processor 812 is configured to determine third information based on the first EPS bearer status information and the PDN connection context, and / or perform another process of the techniques described herein. The communication interface 813 is configured to support communication of the second core network device 810. The memory 811 is configured to store program codes and data for the second core network device 810.

[0330] The processor 812 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 812 may implement or execute various illustrative logic blocks, modules, and circuits described with reference to the disclosed subject matter in this application. Alternatively, the processor may be a combination for performing computational functions, such as a combination of one or more microprocessors, or a combination of a digital signal processor and a microprocessor. The bus 814 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. Buses may be categorized as address buses, data buses, control buses, etc. For ease of illustration, FIG. 25 uses only one thick line to represent a bus, but this does not imply that there is only one bus or one type of bus.

[0331] In another embodiment of the present application, a system is further provided, the system including: a user equipment (UE), a first core network device, and a second core network device, wherein the user equipment is the user equipment provided in Figure 14 or 15, or the user equipment provided in Figure 20 or 21, and / or the first core network device is the first core network device provided in Figure 16 or 17, or the first core network device provided in Figure 22 and Figure 23, and / or the second core network device is the second core network device provided in Figure 18 or 19, or the second core network device provided in Figure 24 or 25.

[0332] In another embodiment of the present application, there is further provided a computer-readable storage medium having computer-executable instructions stored thereon, which, when executed by at least one processor of the device, cause the device to perform the method for moving between communication systems provided in Figure 3, Figure 4, or Figure 8, or to perform the method for moving between communication systems provided in Figure 9 or Figure 13.

[0333] In another embodiment of the present application, a computer program product is provided. The computer program product includes computer-executable instructions, and the computer-executable instructions are stored in a computer-readable storage medium. At least one processor of a device may read the computer-executable instructions from the computer-readable storage medium, and the at least one processor executes the computer-executable instructions so that the device performs the method for moving between communication systems provided in Figure 3, Figure 4, or Figure 8, or the method for moving between communication systems provided in Figure 9 or Figure 13.

[0334] In these embodiments of the present application, when a UE establishes a PDN connection, the UE instructs a first core network entity to determine first QoS flow information, which belongs to a second communication system and corresponds to a first EPS bearer of the UE in the first communication system, by using first information. The first core network entity then determines and stores the first QoS flow information and transmits the first QoS flow information to the UE by using a first message. When the UE moves from the first communication system to the second communication system, the UE and the first core network entity may determine QoS flow information to be used by the UE in the second communication system based on the first QoS flow information, whereby a mapping between the first EPS bearer and the first QoS flow information is performed and active bearers are aligned when the UE moves from the first communication system to the second communication system, thereby ensuring a seamless transition of the UE to the second communication system.

[0335] Finally, it should be noted that the above description is merely a specific implementation form of the present application, and is not intended to limit the protection scope of the present application. Any modifications or replacements disclosed in the present application shall fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be governed by the protection scope of the claims. [Explanation of symbols]

[0336] 300 User Equipment 301 Receiving Unit 302 Storage Unit 303 Mobile Unit 304 Decision Unit 305 Transmitting Unit 306 Delete Unit 310 User Equipment 311 memory 312 processors 313 Communication Interface 400 First Core Network Device 401 Decision Unit 402 Transmission Unit 403 Storage Unit 404 receiving unit 410 First Core Network Device 411 memory 412 processors 413 Communication Interface 500 Second Core Network Device 501 Acquired Units 502 Decision Unit 503 Transmitting Unit 510 Second Core Network Device 511 memory 512 processors 513 Communication Interface 600 user devices 601 Setting Unit 602 Mobile Unit 603 receiving unit 604 Decision Unit 605 Transmitting Unit 606 Delete Unit 610 User Equipment 611 memory 612 processor 613 Communication Interface 700 First Core Network Device 701 receiving unit 702 Decision Unit 703 Delete Unit 710 First Core Network Device 711 memory 712 processor 713 Communication Interface 800 Secondary Core Network Device 801 Acquisition Units 802 transmitting unit 803 Decision Unit 810 Second Core Network Device 811 memory 812 processor 813 Communication Interface

Claims

1. A method, the method being applied for a user equipment, comprising: In a process of establishing a packet data network (PDN) connection in a first communication system, sending first information to a first core network entity, the first information indicating that the PDN connection is movable from the first communication system to a second communication system; receiving a first message from the first core network entity, the first message being used to set up or modify a first Evolved Packet System (EPS) bearer in the first communication system, the first message including first Quality of Service (QoS) flow information of the second communication system corresponding to the first EPS bearer; storing the first QoS flow information; moving from the first communication system to the second communication system; determining second QoS flow information to be used in the second communication system based on a first condition, the first condition including the first QoS flow information; A method comprising:

2. The step of storing the first QoS flow information includes: The method of claim 1 , further comprising: storing a correspondence between an EPS bearer context of the first EPS bearer and the first QoS flow information.

3. A method as described in claim 1 or 2, wherein the first EPS bearer is a default bearer and the first QoS flow information includes one or more of the following information: session aggregate maximum bit rate, and QoS rules.

4. The method of claim 1 , wherein the first QoS flow information is included in a Protocol Configuration Options (PCO) field of the first message.

5. The step of moving from the first communication system to the second communication system includes:

5. The method of claim 1, comprising receiving a handover command from a base station in the first communication system, the handover command including a QoS flow identifier and a session identifier.

6. 6. The method according to claim 1, wherein the first communication system is a fourth generation communication system and the second communication system is a fifth generation communication system.

7. The method of claim 3 , wherein the QoS rule includes at least one of a QoS rule identifier, a QoS flow identifier, a packet filter, or a priority.

8. 8. The method according to claim 1, wherein the first core network entity is a Session Management Function Entity+Control Plane PDN Gateway (SMF+PGW-C).

9. The method according to any one of claims 1 to 8, wherein the first QoS flow information further includes one or more of the following information: a service and session continuity mode, and a PDU session identifier.

10. 10. A user equipment comprising: a memory, a processor, a communication interface, and a bus, wherein the memory stores code and data, the processor, the memory, and the communication interface are connected using the bus, and the processor executes the code in the memory such that the user equipment performs the method of any one of claims 1 to 9.

11. A communications device for user equipment, comprising:

10. A communications device comprising at least one processor configured to call a computer program from a memory and to execute said computer program to cause said user equipment to perform the method of any one of claims 1 to 9.

12. A computer-readable storage medium storing instructions that, when executed by a device for user equipment, cause the device to perform the method of any one of claims 1 to 9.

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