Non-handover based mobility management in hierarchically structured cellular networks

Hierarchical cell structure (HCS) is considered as a possible solution to support users in shadowing area or hot zone area. In HCS systems, both co-channel interference and mobility management are the most important problems. In this paper, we propose a new mobility management method that efficiently preserves the data rate of the mobile user passing small overlaid cell area. In the proposed method, handover is not used when the mobile user passes the overlaid cell area. Therefore, it is not affected by ping-pong and handover overhead. Instead, specific channel utilization is used to prevent co-channel interference and to guarantee quality of service in common channel. We show the procedure of the proposed mobility management method, and channel utilization in this method. We also evaluate the rate regions where the proposed method can support higher data rate than handoverbased method. System level simulation based on IEEE 802.16m system shows that the proposed method is more efficient in HCS system than handover-based method.