HARTES ÜBERGABEVERFAHREN AUS EINEM DRAHTLOSEN LOKALBEREICHNETZWERK IN EIN MOBILES TELEFONNETZWERK

摘要

A system and a method are provided for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network. The method includes: establishing a link between a user terminal (UT) and a serving WLAN, and a call via the WLAN link; simultaneously monitoring a serving cellular telephone network; forwarding information identifying the UT within the cellular network, to the serving WLAN; in response to losing the link with the serving WLAN, performing a hard handoff to the cellular network; and, continuing the call via the cellular network. Generally, the hard handoff can be performed if the WLAN is able to communicate the UT's identity to the cellular telephone, as the UT's position can be determined by the cellular network. The hard handoff is performed with the UT receiving resource allocations in a common control channel message, such as a Short Message Ser vice (SMS) or paging message.