A Vertical Handover Trigger Mechanism Based on Gray Prediction

Cross layer handover schemes are expected to provide seamless services for mobile terminal in the heterogeneous wireless networks. To reduce the handover delay time, link layer must timely trigger handover protocols of layer 3 so that they can finish handover procedures before current wireless link terminates. Because of limited computing power with the mobile terminal and larger packet loss rate for vertical handover, in this paper, we propose a novel trigger mechanism based on gray prediction. Firstly, the time required to perform handover is estimated. Secondly, the time to trigger a Link_Going_Down is determined according to convex optimization theory, both considering the received signal strength from currently connected network and target access network. Simulation results show that this mechanism can obtain higher prediction accuracy with the same prediction step, and the packet loss rate can be controlled within 5% when the terminal moving speed less than 5m/s.