SIP TIMER MODIFICATION TO SUPPORT IMS CALL FALLBACK

Abstract

A user equipment (UE) is configured to initiate a packet-switched call via a first radio access technology (RAT) and start a plurality of session initiation protocol (SIP) timers responsive to initiating the call. Responsive to at least one condition being present with initiation of a fallback process for the call, the UE is configured to restart a set of the plurality of SIP timers for the fallback process, wherein the set can include some or all of the plurality of SIP timers started with initiation of the call. Each SIP timer has a corresponding default timer duration, and in some instances restarting a SIP timer of the set includes restarting the SIP timer with a starting duration equal to a sum of the default timer duration and an offset so that the restarted SIP timer provides for a greater duration than when originally started to better accommodate the fallback process.

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