Dual-mode communication device and call handoff method

摘要

A communication unit (10) includes a mobility agent (225) for providing handoffs between a cellular network and a wireless local area network (11). The communication unit (10) determines if it should switch between the wireless local area network (11) and the cellular network for obtaining service, requests a handoff to the wireless local area network (11) or to the cellular network by sending a SIP message addressed to either a public number (229) or a private number (231) associated with the communication unit (10) upon making the determination. The communication unit (10) accepts a new call from an enterprise server (12) over the determined network. Corresponding methods of providing a hand-off is described.