Velocity aware vertical handovers

A wireless heterogeneous network consists of various wireless networks such as Worldwide Interoperability for Microwave Access (WiMAX), Wireless Fidelity (WiFi), cellular networks etc. Vertical handover (VHO) is a procedure that enables continuous seamless communication in these heterogeneous systems. This paper considers the speed as an aspect of motion as input parameters for the handover decision. Two novel methods for speed estimation are proposed: Velocity Aware Handover Approach (VAHA) is the more simple approach and it uses the FSPL equation for estimation of the speed, and Angle of Arrival VAHA (AoA_VAHA) that is more complex and it uses the Angle of Arrival as additional information for the handover decision. The paper analyzes the performance of both methods and compares them to a RAT selection mechanism based on radio quality (RQ) in terms of user´s perception quality (jitter), energy efficiency, and signal overhead in the network. Both proposed approaches are analyzed on a hybrid WiMAX - WiFi simulation platform. The results show that AoA_VAHA outperforms the RQ mechanism and the VAHA. The advantage of VAHA is in its simplicity and energy efficiency.