Date Added: Dec 2011
Next generation wireless systems consist of heterogeneous wireless networks. Wireless LAN (WLAN) and cellular mobile radio systems will be important part of heterogeneous networks. Universal Mobile Telecommunication System (UMTS) provides wide-area coverage, high mobility but relatively low data rate. WLAN is designed for low-range, high/medium data rate access, low mobility and can be used as a complement to larger cellular mobile radio systems. In this paper, the authors consider a simple heterogeneous system of WLAN and UMTS cell. Vertical handover plays a vital role in ensuring quality of service in heterogeneous networks.