# US 11,122,533 B2 · Method and user equipment for handling dual registration in wireless communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,533 B2 - Document ID: US11122533B2 - Status: Granted - Kind: B2 - Application number: 16/666,980 - Filed: 2019-10-29 - Published: 2020-04-30 - Granted: 2021-09-14 - Earliest claimed: 2018-10-29 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Vijay Ganesh Surisetty; Prasad Basavaraj Dandra; Seshadri Elluru; Siddhi Chandrashekhar Mayekar; Rajdeep Kaur; Ayush Raj; Lalith Kumar - Web page: https://patentgrep.com/patent/US11122533B2 ## CPC - H04W 60/005: {Multiple registrations, e.g. multihoming} - H04L 65/1016: IP multimedia subsystem [IMS] - H04L 65/1073: Registration or de-registration - H04W 8/02: Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks - H04W 84/042: {Public Land Mobile systems, e.g. cellular systems} - H04W 88/06: adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Embodiments herein disclose a method for handling dual registration of user equipment (UE) in a wireless communication system. The method includes registering the UE on a fourth generation Radio Access Technology (4G RAT) and a fifth generation RAT (5G RAT). Further, the method includes determining, by the UE, an occurrence of at least one event. Further, the method includes suspending, by the UE, the registration on the 5G RAT. Further, the method includes performing, by the UE, communication using the registration on the 4G RAT. ## Claims ### Claim 1 A method for handling a dual registration in a wireless communication system, the method comprising: registering a User Equipment (UE) on a first Radio Access Technology (RAT) and a second RAT; determining, by the UE, an occurrence of at least one service degradation event associated with service on the first RAT; suspending, by the UE, the registration on the second RAT based at least in part on the occurrence of the at least one service degradation event associated with the service on the first RAT; and performing, by the UE, communication using the registration on the first RAT. ### Claim 2 (depends on 1) The method of claim 1, wherein registering the UE on the first RAT and the second RAT comprises: registering the UE on the second RAT; detecting that an IP Multimedia Subsystem (IMS) service is unavailable on the second RAT; and registering, by the UE, on the first RAT. ### Claim 3 (depends on 1) The method of claim 1, wherein registering the UE on the first RAT and the second RAT comprises: registering the UE on the first RAT; detecting that an IP Multimedia Subsystem (IMS) service is unavailable on the first RAT; and registering, by the UE, on the second RAT. ### Claim 4 (depends on 1) The method of claim 1, wherein the at least one service degradation event comprises an unavailability of a Circuit Switched Fallback (CSFB) on the first RAT, a service loss or failure at the first RAT, and a mobility of the UE to from the first RAT to a legacy network, wherein the legacy network comprises a second generation (2G) network or a third generation (3G) network. ### Claim 5 (depends on 1) The method of claim 1, wherein the first RAT is a 4G RAT and the second RAT is a 5G RAT. ### Claim 6 (depends on 1) The method of claim 1, wherein the dual registration is provided when N26 interface is supported between a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF) entity. ### Claim 7 (depends on 1) The method of claim 1, further comprising: shifting one or more public data networks (PDNs) from the second RAT to the first RAT based on detecting that an IP Multimedia Subsystem (IMS) service is unavailable on the second RAT. ### Claim 8 (depends on 7) The method of claim 7, wherein detecting that the IP Multimedia Subsystem (IMS) service is unavailable on the second RAT comprises at least one of determining a roaming area not allowed condition for the second RAT, determining no suitable cells are available in a tracking area (TA) of the second RAT, or determining an abnormal condition for the second RAT. ### Claim 9 (depends on 1) The method of claim 1, further comprising: determining, by the UE, whether a common Public Land Mobile Network (PLMN) is available in a Registered Public Land Mobile Network (RPLMN) and equivalent PLMN list currently available with the first RAT and an RPLMN and equivalent PLMN list previously received from a second RAT, or determining, by the UE, whether an Equivalent Home PLMN (EHPLMN) is available in each of the RPLMN and equivalent PLMN list currently available with the first RAT and the RPLMN and equivalent PLMN list previously received from the second RAT, wherein the UE is registered on the second RAT based at least in part on whether either of the common PLMN or the EHPLMN is available. ### Claim 10 A user equipment (UE) for handling a dual registration in a wireless communication system, the UE comprising: a memory; and a processor, coupled with the memory, configured to: register on a first Radio Access Technology (RAT) and a second RAT; determine an occurrence of at least one service degradation event associated with service on the first RAT; suspend the registration on the second RAT based at least in part on the occurrence of the at least one service degradation event associated with the service on the first RAT; and perform communication using the registration on the first RAT. ### Claim 11 (depends on 10) The UE of claim 10, wherein registering the UE on the first RAT and the second RAT further comprises: registering the UE on the second RAT; detecting that an IP Multimedia Subsystem (IMS) service is unavailable on the second RAT; and registering on the second RAT. ### Claim 12 (depends on 10) The UE of claim 10, wherein registering the UE on the first RAT and the second RAT further comprises: registering the UE on the first RAT; detecting that an IP Multimedia Subsystem (IMS) service is unavailable on the first RAT; and registering on the second RAT. ### Claim 13 (depends on 10) The UE of claim 10, wherein the at least one service degradation event comprises an unavailability of a Circuit Switched Fallback (CSFB) on the first RAT, a service loss or failure at the first RAT, and a mobility of the UE to a legacy network, wherein the legacy network comprises a second generation (2G) network or a third generation (3G) network. ### Claim 14 (depends on 10) The UE of claim 10, wherein the first RAT is a 4G RAT and the second RAT is a 5G RAT. ### Claim 15 (depends on 10) The UE of claim 10, wherein the dual registration is provided when N26 interface is supported between a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF) entity.