# US 2020/0404479 A1 · Initial operation method for roaming terminal accessing network in mobile communication environment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0404479 A1 - Document ID: US20200404479A1 - Status: Published application - Kind: A1 - Application number: 16/336,704 - Filed: 2017-09-27 - Published: 2020-12-24 - Earliest claimed: 2016-10-06 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Hoyeon LEE; Sunghoon KIM; Youngkyo BAEK; Jungje SON - Web page: https://patentgrep.com/patent/US20200404479A1 ## CPC - H04W 8/06: Registration at serving network Location Register, VLR or user mobility server - H04W 28/24: Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service] - H04W 60/00: Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration - H04W 8/20: Transfer of user or subscriber data - H04W 60/002: {Registration for requesting network slices} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present disclosure relates to a communication technique for converging, with an IoT technology, a 5G communication system for supporting a higher data transmission rate than a 4G system, and a system therefor. The present disclosure may be applied to intelligent services, such as smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail businesses, and security and safety related services, on the basis of 5G communication technologies and IoT-related technologies. The present invention suggests a method for providing service information that a roaming terminal seeks to use in an initial access process of the roaming terminal accessing a visited network. ## Claims ### Claim 1 A network attachment method of a terminal in a mobile communication system, the method comprising: transmitting an attach request message including roaming level information mapped to at least one service type that the terminal can receive to a visited network (PLMN); and receiving, if the visited network receives first service type information determined based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information from the home network, an attach response message including second service type information corresponding to the first service type information from the visited network. ### Claim 2 (depends on 1) The method of claim 1, wherein the roaming level information is one of multiple roaming level indices mapped to combinations of multiple service types that the terminal can receive. ### Claim 3 (depends on 2) The method of claim 2, wherein the mapping information between the combinations of the multiple service types and the multiple roaming level indices is stored in the terminal in advance. ### Claim 4 (depends on 1) The method of claim 1, wherein the attach request message further includes a terminal identifier. ### Claim 5 (depends on 1) The method of claim 1, wherein the first service type information relates to a service type that the home network can provide for the terminal based on the service level agreement and the roaming level information, and the second service type information relates to a service type corresponding to the first service type information, which the visited network can provide for the terminal. ### Claim 6 A network attachment control method of a visited network (PLMN) in a mobile communication system, the method comprising: receiving an attach request message including roaming level information mapped to at least one service type that a terminal can receive from the terminal; receiving first service type information determined based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information from the home network; and transmitting an attach response message including second service type information corresponding to the first service type information to the terminal. ### Claim 7 (depends on 6) The method of claim 6, further comprising transmitting a service request message including the roaming level information and a terminal identifier to the home network. ### Claim 8 (depends on 6) The method of claim 6, wherein the roaming level information is one of multiple roaming level indices mapped to combinations of multiple service types that the terminal can receive. ### Claim 9 (depends on 6) The method of claim 6, wherein the first service type information relates to a service type that the home network can provide for the terminal based on the service level agreement and the roaming level information, and the second service type information relates to a service type corresponding to the first service type information, which the visited network can provide for the terminal. ### Claim 10 A network attachment control method of a home network (PLMN) in a mobile communication system, the method comprising: receiving a service request message from a visited network (PLMN), the service request message including roaming level information mapped to at least one service type that a terminal can receive and a terminal identifier of the terminal; determining first service type information based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information; and transmitting a service response message including the first service type information to the visited network. ### Claim 11 (depends on 10) The method of claim 10, wherein determining the first service type information comprises: ascertaining subscriber information based on the terminal identifier; and determining the first service type information based on the service level agreement, the roaming level information, and the subscriber information. ### Claim 12 (depends on 10) The method of claim 10, wherein mapping information between combinations of multiple service types and the roaming level information is stored in the home network in advance. ### Claim 13 A terminal attaching to a network in a mobile communication system, the terminal comprising: a transceiver configured to transmit and receive signals; and a controller connected to the transceiver and configured to control the transceiver to transmit an attach request message to a visited network (PLMN), the attach request message including roaming level information mapped to at least one service type that the terminal can receive and receive, if the visited network receives first service type information determined based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information from the home network, an attach response message including second service type information corresponding to the first service type information from the visited network. ### Claim 14 A visited network (PLMN) for controlling a network attachment in a mobile communication system, the visited network comprising: a transceiver configured to transmit and receive signals; and a controller connected to the transceiver and configured to control the transceiver to receive an attach request message including roaming level information mapped to at least one service type that a terminal can receive from the terminal, receive first service type information determined based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information from the home network, and transmit an attach response message including second service type information corresponding to the first service type information to the terminal. ### Claim 15 A home network (PLMN) for controlling a network attachment in a mobile communication system, the home network comprising: a transceiver configured to transmit and receive signals; and a controller connected to the transceiver and configured to control the transceiver to receive a service request message from a visited network (PLMN), the service request message including roaming level information mapped to at least one service type that a terminal can receive and a terminal identifier of the terminal, determine first service type information based on a service level agreement made for providing subscribers of the visited network and a home network (PLMN) with a roaming service and the roaming level information, and control the transceiver to transmit a service response message including the first service type information to the visited network.