VOSHM: A Velocity Optimized Seamless Handover Mechanism for WiMAX Networks

For seamless handover in heterogeneous wireless networks, service continuity and minimal handover disruption time are the primary requirements. The emerging Media Independent Handover (MIH) standard proposes to address these requirements through the introduction of link performance prediction features. In particular the MIH Event Service introduces a Link_Going_Down event which utilizes L2 performance characteristics to trigger predictive events. While the MIH standard proposes a framework by which L2 events can be communicated to the upper layer, it does provide detail on the performance characteristics which trigger these events. In this paper, we design a MIH based Velocity Optimized Seamless Handover Mechanism (VOSHM) for WiMAX networks. We analyse how the handover probability value, which is a critical parameter used to trigger link going down event, is effected by the velocity of the mobile node. A number of simulation scenarios illustrating handover between WiMAX and 3G networks are evaluated. Our results indicate that VOSHM can reduce more than 95% handover delay in comparison to without utilizing the Link_Going_Down trigger.