heterogenous network, vertical handover

The rapid proliferation of mobile devices, which became one of the life necessities for people, has raised an incremental need for wireless technologies. With the apparent growth in the mobile applications markets in the video, audio, and data (emails and web surfing) and with all the innovations and inventions in the technologies, it makes the fact of the necessity for using the heterogeneous wireless networks. The operators use multi-wireless technologies to provide widespread connectivity that serves the users services anytime anywhere. The user’s expectation is always to connect to the best available network that best suits his application requirements. Based on this expectation, a seamless vertical handover (VHO) technique, and an efficient strategy of selecting the best network without any error or interruption on the running service is required. The major challenge here is how to select the most suitable network and keep connected for a long time without any drawbacks, in a way that maximizes the user satisfaction. The handover or handoff is the process of moving the mobile connection from one network to another (fall-over). Many key factors influence the journey of the VHO and network selection; these factors define the user preferences, identify the application requirements, the required quality of service (QoS) attributes, the handover management and performance issues. Each factor has multiple challenges to be addressed. For example, although the QoS attributes such as bandwidth, latency, throughput, and interference are significant factors that influence the selection criteria, but the user preference attributes are also significant factors, as they represent the user satisfaction and experience