A traffic shedding algorithm for soft-handoff in MC-CDMA systems

In mobile communication environment, an abrupt increase of mobile users in a specific cell makes traffic overloaded and become a so-called hot-spot cell, which causes an unbalanced traffic load condition because the traffic load in the neighboring cells may be light. In order to utilize a limited bandwidth efficiently, it is necessary to use a good mobile handoff strategy to alleviate the unbalanced traffic condition. This paper proposes a complete traffic shedding algorithm (CTSA) for soft handoff efficiently to alleviate the overloaded traffic in the hot-spot cell by adjusting handoff parameters, which virtually reduces the service coverage of the heavy loaded cell without adjusting the transmission power. The mobile users located in the outer area of the hot-spot cell is early handoff to the neighboring cells with light traffic load; and the mobile users in the neighboring cells postpone to handoff to the hot-spot cell, so that the traffic load of the hot-spot cell can be decreased. The proposed algorithm is analyzed and evaluated by simulation; CTSA algorithm shows better performance than the others; it obviously increases system throughput and decreases soft handoff call dropping ratio, and new call blocking ratio.