A system in which a device to device (D2D) communication may be enabled between not just the same cellular providers subscribers but also with subscribers who are from different cellular providers in a region. The system may provide D2D communication interoperability and roaming.

In order for making MTC more efficient and/or secure, a base station forming a communication system connects a UE to a core network. A node serves as an entering point to the core network for a service provider, and transmits traffic between the service provider and the UE. The node establishes, as a connection to the base station, a first connection for directly transceiving messages between the node and the base station. Alternatively, the node establishes a second connection for transparently transceiving the messages through a different node that is placed within the core network and has established a different secure connection to the base station.

In order for making MTC more efficient and/or secure, a base station forming a communication system connects a UE to a core network. A node serves as an entering point to the core network for a service provider, and transmits traffic between the service provider and the UE. The node establishes, as a connection to the base station, a first connection for directly transceiving messages between the node and the base station. Alternatively, the node establishes a second connection for transparently transceiving the messages through a different node that is placed within the core network and has established a different secure connection to the base station.

The disclosure relates to a fifth generation (5G) or sixth generation (6G) communication system. Embodiments herein disclose methods for maintaining priority of a VPLMN during a PLMN selection procedure by a UE. The method includes ignoring a pre-configured priority for a VPLMN and considering the VPLMN as a lowest priority in response to determining that the UE has entered a state and the second SOR information is not received before the UE enters the state or the received second SOR information security check is not successful. The method includes considering a priority of the VPLMN as the pre-configured priority by not considering the VPLMN as a lowest priority and stopping the timer associated with the “first SOR security check not successful” in response to determining that the UE receives the second SOR information and a second SOR security check is successful before the UE enters the state.

A method for transmitting and receiving a signal related to switching 3rd generation partnership project (3GPP) access to a 5th generation system (5GS) in an evolved packet system (EPS) in a wireless communication system includes: a step in which a second access and mobility management function (AMF) receives a message, related to a registration request and including a first 5G globally unique temporary identifier (5G-GUTI), from a UE that receives non-3GPP access service through the 5GS and 3GPP access service through the EPS; and a step in which the second AMF transmits to the UE, a message related to a registration acceptance and including a second 5G-GUTI. The first 5G-GUTI includes ID information on the first AMF which serves the non-3GPP access of the UE, and the second 5G-GUTI includes ID information on the second AMF which serves both the non-3GPP access and the 3GPP access of the UE.

A method for transmitting and receiving a signal related to switching 3rd generation partnership project (3GPP) access to a 5th generation system (5GS) in an evolved packet system (EPS) in a wireless communication system includes: a step in which a second access and mobility management function (AMF) receives a message, related to a registration request and including a first 5G globally unique temporary identifier (5G-GUTI), from a UE that receives non-3GPP access service through the 5GS and 3GPP access service through the EPS; and a step in which the second AMF transmits to the UE, a message related to a registration acceptance and including a second 5G-GUTI. The first 5G-GUTI includes ID information on the first AMF which serves the non-3GPP access of the UE, and the second 5G-GUTI includes ID information on the second AMF which serves both the non-3GPP access and the 3GPP access of the UE.

To provide a communication terminal that ensures the coincidence of Paging timing between a UE and a control device when an eDRX parameter is updated in a control device, a communication terminal (10) according to the present disclosure includes a receiving unit (11) for receiving a Tracking Area Registration Accept message or a Location Registration Accept message sent from a control device (30), and a sending unit (12) for sending a Tracking Area Registration Complete message or a Location Registration Complete message to the control device (30) when a first eDRX (Extended Idle Mode DRX) parameter is contained in the Tracking Area Registration Accept message or the Location Registration Accept message.

To provide a communication terminal that ensures the coincidence of Paging timing between a UE and a control device when an eDRX parameter is updated in a control device, a communication terminal (10) according to the present disclosure includes a receiving unit (11) for receiving a Tracking Area Registration Accept message or a Location Registration Accept message sent from a control device (30), and a sending unit (12) for sending a Tracking Area Registration Complete message or a Location Registration Complete message to the control device (30) when a first eDRX (Extended Idle Mode DRX) parameter is contained in the Tracking Area Registration Accept message or the Location Registration Accept message.

Communication methods and an apparatus are provided. The method includes: After receiving a registration request sent by a terminal device, an AMF sends first information to a UDM network element, where the first information includes NSSAI requested by the terminal device, S-NSSAI in a home domain corresponding to the NSSAI requested by the terminal device, or subscribed S-NSSAI of the terminal device. The AMF receives SoR information of the terminal device from the UDM, where the SoR information includes information about each preferred PLMN of the terminal device. The AMF sends the SoR information to the terminal device. Based on this solution, when determining the SoR information of the terminal device, the UDM may determine each preferred PLMN of the terminal device based on a network slice expected (requested) by the terminal device.

Various embodiments that relate to local communication are discussed. A radio from one geographical area can enter a communication environment of a different geographical area. However, if the radio still functions consistent with the previous geographical area, then the radio will not blend into the new geographical area. Therefore, the radio can alter operational characteristics when entering the new geographical area such that the radio blends into the new geographical area from a radio frequency perspective.