Context-Aware Handover Decision in an Enhanced Media Independent Handover Framework

Abstract

Recent developments in heterogeneous mobile networks emphasize the necessity of more intelligent and context-aware handover decisions. However, the complexity and overhead of collecting and managing context information are the main difficulties in context-aware handovers. Media independent handover (MIH) framework which has been proposed by IEEE 802.21 only provides static context of access networks through its information service. This paper elaborates the idea of handoff-aware network context gathering for renewal of dynamic context in MIH information server. An extension is proposed on MIH framework to efficiently accommodate the dynamic context of access networks along with the ordinary static context in IS. The paper presents analytical evaluation of the proposed context gathering method in terms of context access latency and signalling overhead. Also, the paper presents a policy-based context-aware handover model based on the proposed extension. A well defined policy format is proposed for straight description of users’, devices’, and applications’ preferences and requirements. In contrast to traditional policy-based methods, a multi-policy scheme is proposed that exploits rank aggregation methods to employ a set of matching policies in target point of attachment selection. Simulations have been carried out in NS2 to verify the performance of the proposed context gathering method and the proposed handover decision model. Simulation results show better performance in terms of evaluation metrics.