Performance Evaluation of Vertical Handoff in Wireless Data Networks

The next generation wireless systems will support heterogeneous traffic with seamless mobility. A single network alone cannot cope up with such heterogeneous requirements. Hence it is desirable to interoperate between diverse and complementary radio access technologies (RATs).In such system, user will switch between different radio access technologies (RATs) to satisfy the User/application requirement and this process is known as vertical handovers/handoff. The process of network switching has three phases, network discovery, handoff decision and execution. The decision phase plays a crucial role in resource utilization and user/application quality of service (QoS) requirement. Hence it is essential to model and evaluate the handoff decision system. The performance evaluation metrics of handoff decision systems are handoff dropping probability and new call blocking probability. The dynamics of handoff decision metrics depend on set of handoff decision system parameters such as available bandwidth (ABW), users, Bit Error Rate (BER) and network traffic. The results of performance evaluation are used to develop a novel intelligent vertical handoff decision technique to achieve optimum tradeoff between set of handoff decision criteria. Finally, sensitivity analysis of system parameters on four traffic classes and two vertical handoff decision algorithms along with intelligent vertical handoff decision method are presented.