Patent ID: 8599776

Claim:
A method of operating a communication system comprising: establishing a voice call having an initial signaling channel and an initial voice channel between a first wireless device and a second wireless device over a first wireless access system and a second wireless access system, wherein the first wireless access system uses a cellular voice protocol; establishing a new signaling channel for the voice call between the first wireless device and a separate packet network, wherein the separate packet network uses a cellular packet based protocol and the new signaling channel uses a voice over packet control protocol; extending the new signaling channel for the voice call from the separate packet network to the second wireless access system over the first wireless access system; and using the new signaling channel to establish a new voice channel for the voice call between the first wireless device and the second wireless access system over the separate packet network, wherein the first wireless access system does not remain in the new voice channel, and to remove the initial voice channel for the voice call between the first wireless device and the second wireless access system over the first wireless access system, wherein the first wireless access system remains in the new signaling channel between the separate packet network and the second wireless access system.