ABSTRACT
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. 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 Quality of Service (QoS) to a wide range of applications while allowing seamless roaming among a
multitude of access network technologies. This paper is about the comprehensive survey of the VHD algorithms designed
to satisfy these requirements.
Keywords: - Vertical handover;