A Dynamic Traffic Shedding Algorithm for Soft-Handoff in MC-CDMA Systems

摘要

This paper describes a dynamic shedding algorithm which takes step to balance the traffic density of the wireless communication environment. Once sudden increase of mobile users in a specific cell occurs, the traffic becomes overloaded. In this case the cell is called hot-spot cell, which causes an unbalanced traffic load condition because may be the traffic load in the neighboring cells are lighter. Since there is a limited bandwidth, it is necessary to apply a good balancing policy to reduce the unbalanced traffic condition. This paper proposes a complete dynamic traffic shedding algorithm (CDTSA) applicable for soft handoff to decrease the overloaded traffic in the hot-spot cell by dynamically changing the handoff parameters. The change virtually reduces the service coverage of the heavy loaded cell. The mobile users located in the outer area of the hot-spot cell will be forced to early handoff to the neighboring cells with light traffic load; meanwhile mobile users in the neighboring cells postpone to handoff to the hot-spot cell, so that the traffic load of the hot-spot cell is reduced. The proposed algorithm is analyzed and evaluated by simulation; CDTSA algorithm shows better performance than the others while it increases system throughput and decreases soft handoff call dropping ratio, and new call blocking ratio.