Reducing Inter-Cell Handover Events based on Cell ID Information in Multi-hop Relay Systems

Abstract-To reduce handover overhead such as signaling overhead and latency, optimal handover algorithm is needed for Mobile Multi-hop Relay (MMR) systems. This article proposes a novel handover method that reduces inter-cell handover but increases intra-cell handover events, because inter-cell handover has more overhead in view of the system and gives more latency time to users rather compared to intra-cell handover. Therefore, in the proposed scheme, intra-cell handover is encouraged instead inter-cell handover using adaptive hysteresis level. Intra-cell handover performs based on higher hysteresis level than intercell handover. This paper also presents hierarchical relay station ID (RS ID) concept for IEEE 802.16j standard. And, additional method using MOB NBR-ADV message is proposed in case that hierarchical ID could not be used. This proposed algorithm can decrease handover signaling overhead, latency, and unnecessary handovers called ping-pong effect as well. Also, the proposed algorithm is backward compatible with mobile station (MS). Performance analysis and simulation validate the efficiency of the proposed algorithm