International Journal of Engineering Research and Applications (IJERA)
One of the major design issues in heterogeneous wireless networks is the support of vertical handover. Vertical handover occurs when a mobile terminal switches from one network to another (e.g., from WLAN to CDMA 1xRTT). Seamless handover between different access technologies is a great challenge as it needs to obey different performance of QoS and security constraints. Subscribers are becoming more demanding regarding roaming capabilities across different networking technologies such as Wi-Fi, WiMAX, and CDMA as they claim service continuity with QoS requirement and good security features.