A session establishment method and an apparatus, such that an established packet data network (PDN) connection is transferred to a network slice in a fifth generation (5G) network during inter-system mobility of a terminal. The method includes receiving, by a terminal from a control plane function entity, corresponding network slice information used for transferring an established PDN connection to a 5G network, where the corresponding network slice information includes corresponding single network slice selection assistance information (S-NSSAI). The method further includes sending a packet data unit (PDU) session establishment request, where the PDU session establishment request includes corresponding S-NSSAI used for transferring a first PDN connection to the 5G network and a corresponding data network name (DNN) used for transferring the first PDN connection to the 5G network, and the first PDN connection is any one of one or more established PDN connections.

A message protection method and an apparatus are disclosed. The method includes: When a terminal prepares to hand over from a first-standard system to a second-standard system, the terminal may not have a security context of the second-standard system after handover. Therefore, in the method of the present disclosure, the terminal performs integrity protection on a registration request message and a location update request message by using an integrity key in a security context of the first-standard system before handover. Both the registration request message and the location update request message are messages for triggering handover. Therefore, in the method, security protection is implemented on the message for triggering handover, thereby helping improve communication security.

Apparatuses, systems, and methods for a wireless device to perform methods for de-registration of the wireless device from a first access type over a second access type. Methods also include procedures for maintaining state machines associated with both access types as well as procedures to determine a connection for re-transmitting a de-registration request and to avoid collisions between procedures associated with the first and second access types. Further, methods include an information element configured to indicate which access type has been de-registered.

A wireless communication network serves User Equipment (UEs) over wireless network slices that comprise Network Exposure Functions (NEFs). The egress AF receives a slice request from an external data system and transfers the slice request to the NEF in the wireless network slice. An Access and Mobility Management Function (AMF) selects the wireless network slice for the UE. The UPF in the wireless network slice receives user data from the UE and transfers the user data to the ingress AF in the wireless network slice. The ingress AF transfers the user data to the NEF in the wireless network slice. The NEF transfers the user data to the egress AF in response to the slice request. The egress AF transfers the user data to the external data system in response to the slice request.

A method performed by user equipment (UE) includes receiving a request to access a service unavailable through a first network cell associated with the UE, and receiving a message from an access device associated with the first network cell, wherein the message identifies a plurality of second network cells providing the service.

A method in a first base station for managing a conditional operation related to a user equipment UE includes sending, by processing hardware to the UE, a conditional connection information including at least one of a (i) configuration data related to a second base station in order for the UE to operate in dual connectivity with the first base station and the second base station, or (ii) one or more conditions connecting to the second base station (2202). The method also includes, in response to determining, by the processing hardware, that the UE is to suspend a radio connection with the first base station (2204): causing the UE to suspend a radio connection with the first base station (2206), and causing the second base station to release the conditional connection information (2208).

A method performed by a first NF service provider in 5GC, for enabling a specific functionality for a specific area of a communications network. The 5GC further comprises one or more second NF service provider managing the specific functionality in the 5GC and a NF service consumer requesting the specific functionality to be performed by the second NF service provider for the specific area. The method comprises obtaining, from the NF service provider, information regarding the functionality and the network area supported. The method further comprises receiving a request for the address of the second NF service provider supporting the functionality in a desired network area. The method further comprises determining the address of the NF service provider supporting the functionality for the network area indicated and sending the determined address to the NF service consumer.

A communication method and a communications apparatus, the method including receiving, by an access and mobility management function (AMF) entity, a first message from a first access network device, where the first message comprises information for indicating to hand over a voice service of a terminal from a packet switched (PS) domain to a circuit switched (CS) domain, the first message further comprises identification information of a target device, and the target device is a second access network device in a 3G network, and sending, by the AMF entity, through a mobility management entity (MME) a request message to a mobile switching center (MSC) entity, where the request message comprises information indicating a source of the first message.

The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. According to an aspect of the embodiments of the present disclosure, a method for supporting handover is provided, comprising: receiving a message from a central unit control plane entity of a target base station; receiving a data packet from a source base station; and discarding a packet data convergence protocol (PDCP) service data unit (SDU) including the PDCP sequence number (SN) in the received data packet according to the indication of the message. The problem of coordinated work between the source base station and the target base station during the handover process may be solved. Especially when the source base station and/or the target base station support the separation of the control plane and the user plane, ensure that the central unit control plane entity of the source base station, the central unit user plane entity of the source base station, the central unit control plane entity of the target base station and/or the central unit user plane entity of the target base station may fully coordinately work.

Techniques for call recovery for multiple call failures are described and may be implemented via a wireless device to adapt to a variety of different wireless scenarios. For instance, when multiple call failures for a call occur over a particular set of radio access technologies, an IP-based call and/or a direct device-to-device call can be implemented to complete the call.