The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 08, 2025
Filed:
Aug. 13, 2020
Apple Inc., Cupertino, CA (US);
Vijay Venkataraman, San Jose, CA (US);
Krisztian Kiss, Hayward, CA (US);
Shashikant Tiwari, Sunnyvale, CA (US);
Srinivasan Nimmala, San Jose, CA (US);
Lakshmi N. Kavuri, Cupertino, CA (US);
Shivani Suresh Babu, San Jose, CA (US);
Sree Ram Kodali, Sunnyvale, CA (US);
Sridhar Prakasam, Freemont, CA (US);
Stephen C. Schweizer, Mountain View, CA (US);
Yifan Zhu, San Jose, CA (US);
Apple Inc., Cupertino, CA (US);
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.