| 摘要 |
<p>PURPOSE: A vertical handover method is provided to support seamless data transmission service to a portable terminal which moves in an area in which UMTS(Universal Mobile Telecommunication System) service and WLAN(Wireless Local Area Network) service are both available and enable users to select more stable network. CONSTITUTION: A portable terminal which moves toward the service domain of a connecting point requests resources to the connecting point and receives a response message(S105). The portable terminal requests vertical downward handover to an SGSN(Serving GPRS Supporting Node)(S107). The SGSN requests resource allocation about the portable terminal to a WLAN gateway and receives the response message(S111). If the SGSN permits the hand over, the portable terminal completes hand over to WLAN network and transmits a complete message to the SGSN(S115). The SGSN switches the address value of network resource(S117).</p> |
