Patent ID: 9642043
Date: 2017-05-02
CPC Classifications: H04W

Claim:
1. A method comprising: receiving, by a first serving system in a first radio access network (RAN) that provides service under a first air interface protocol, an incoming call directed to a user equipment (UE); sending, by the first serving system, to an interworking server that facilitates communications between the first RAN and a second RAN that provides service under a second air interface protocol, a page message that indicates the incoming call under the first air interface protocol, such that the interworking server provides the page message for transmission to the UE, by a base station in the second RAN, via a paging channel of the second RAN, wherein the second air interface protocol is different from the first air interface protocol; receiving, by a second serving system in the first RAN, a page response message that is transmitted by the UE in response to the page message, wherein the page response message comprises an identifier of the interworking server inserted into the page response message by the UE, and wherein the second serving system is different from the first serving system; based at least in part on the identifier of the interworking server, the second serving system determining that the incoming call was received by the first serving system; and responsively initiating an inter-system handoff to handoff the incoming call from the first serving system to the second serving system.