Enhancement of internet access quality by seamless handoff across WLAN and UMTS networks

Third generation cellular networks and 802.11b Wireless LAN (WLAN) are complementary technologies. Due to the mutual complementary features of wide coverage and high data rate, the inter networking between 3G mobile networks and WLAN is a global trend of wireless communication. One of the basic requirements is to support seamless mobility in wireless networks. Seamless means smooth transition, such that user does not perceive any delay or interruption of service. The main objective is to design a handoff decision criterion suitable to the situation. The purpose of the handoff is to keep continuous or seamless service to mobile users through different cells or network coverage. It is consequently of special importance for wireless networks.