The International Fellowship of Christians and Jews
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 Quality of Service (QoS) and security constraints. Vertical Handover Decision (VHD) algorithms are essential components of the architecture of the forthcoming Fourth Generation (4G) heterogeneous wireless networks. These algorithms need to be designed to provide the required QoS to a wide range of applications while allowing seamless roaming among a multitude of access network technologies.