Patent ID: 9215641
Filing Date: 2015-12-15
Classification: H04L,H04W

Abstract:
1. A method for call handoff between a first wireless network and a second wireless network for a multi-mode mobile station, said multi-mode mobile station including a first interface for wireless communication with said first wireless network and a second interface for wireless communication with said second wireless network, said method comprising: said multi-mode mobile station becoming engaged in a call with an endpoint via said first interface; while said multi-mode mobile station is engaged in said call with said endpoint via said first interface, said multi-mode mobile station transmitting a handoff request, wherein said handoff request comprises a Session Initiation Protocol (SIP) UPDATE message that requests an update to involve said second interface in said call; after transmitting said handoff request, said multi-mode mobile station becoming engaged in said call with said endpoint via said second interface and receiving media for said call via said second interface; said multi-mode mobile station storing said media, thereby accumulating stored media; said multi-mode mobile station receiving a handoff instruction, wherein said handoff instruction comprises a SIP response message that directly responds to said SIP UPDATE message; and in response to said handoff instruction, said multi-mode mobile station conveying said stored media and continuing said call with said endpoint via said second interface.