5G NR voice call EPS fallback enhancements

US12273940B2 · kind B2 · utility

Assignee

• Apple Inc. · US

Inventors

• Vijay Venkataraman · San Jose, US
• Krisztian Kiss · Cupertino, US
• Shashikant Tiwari · Jersey City, US
• Srinivasan Nimmala · San Jose, US
• Lakshmi N. Kavuri · San Jose, US
• Shivani Suresh Babu · San Jose, US
• Sree Ram Kodali · Sunnyvale, US
• Sridhar Prakasam · Cupertino, US
• Stephen C. Schweizer · Mountain View, US
• Yifan Zhu · Zhejiang, CN

Key dates

• Filing date: Aug 13, 2020
• Grant date: Apr 8, 2025
• Expiry date: Jul 9, 2041

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04W80/10
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

Apparatuses, systems, and methods for a user equipment device (UE) to perform methods for EPS fallback when initiating a voice call while camped on a 5G cell. The UE may camp on a 5G network by performing an IMS registration procedure/IMS SIP invite procedure with an IMS. The UE may initiate a voice call and determine that the voice call cannot be established over the 5G NR network. In response, the UE may perform a TAU procedure or an attachment procedure with a cell of a 4G network. The IMS may be transferred to the 4G network during TAU/attachment procedure. The UE may, in response to determining that it is barred from the 4G network, transition back to the 5G network and transmit, to the 5G NR network, a SIP cancel request to allow a context associated with the UE to be cleared from the IMS.