A beacon-based handover scanning mechanism with QoS support in WiMAX femtocell architecture

WiMAX femtocell architecture has gained a lot of attention because of its better indoor service provision through traffic sharing between WiMAX and femtocell. However, since the signal of a WiMAX base station (BS) is usually stronger than that of a femtocell base station (fBS), the handover procedure of mobile stations may not be triggered due to the stronger signal association. And, a huge number of fBSs deployed within a WiMAX BS coverage area will require extra power to scan all fBSs for a handover determination. In this article, we propose a beacon-based handover scanning mechanism with Quality of Service (QoS) support. Through the modified beacons and MOB_NBR-ADV messages, a neighbor cell list with QoS parameters is generated automatically at each mobile station. The decision criteria for handover triggering and an appropriate target cell selection are also presented. The QualNet simulation results demonstrate that along with increased fBSs, the proposed mechanism can improve the total system throughput from 37% to 51% and obtain higher bandwidth utilization in the case of increasing number of fBSs, as compared with Full Scan and Neighbor Cell Information Mechanisms.