An adaptive soft handover algorithm for traffic-load shedding in the WCDMA mobile communication system

In a mobile communication environment, an abrupt increase of mobile users in a specific cell causes an unbalanced traffic-load distribution. When the increased traffic-load exceeds the link capacity of a WCDMA system, it significantly degrades the traffic quality of the mobile users. In this paper, we propose an adaptive soft handover algorithm (ASHA) to efficiently alleviate the overloaded traffic in a cell by adjusting handover parameters. The proposed algorithm virtually reduces the service coverage of the overloaded cell without adjustment of base station transmission power. Consequently, mobile users located in the area farthest away from the heavily loaded cell site are handed over to lightly loaded neighboring cells, so that the traffic-load of the overloaded cell is decreased. The performance of the proposed algorithm is analyzed in path loss and shadow fading environments and is compared with that of a conventional soft handover algorithm.