A Fault-Tolerant Capacity Enhancement Strategy for the Speed-Sensitive Allocation in Hierarchical Wireless Networks

Abstract:- Hierarchical cellular networks that employ microcells with overlaying macrocells have been proposed to increase the traffic-carrying capacity and circuit quality. A major drawback is that a large number of handoff procedures usually take place when the calls cross the cell boundary. Accordingly, the type of speed-sensitive (SS) allocation that can decrease the handoff probability was applied. However, some system problems such as the imbalance of the traffic loads with the occupied bandwidth, base stations (BSs) failed to provide wireless communication service, or the wired link failures which will lessen the traffic-carrying capacity of the SS strategy. This study proposes a fault-tolerant capacity enhancement strategy for the SS strategy. When there are variations in traffic, our strategy can adapt the system bandwidth to the traffic loads among BSs. When a BS fails to provide wireless communication service, its occupied channels cannot be used to provide services. Our strategy can revoke the occupied channels of the failed BS and reallocate to other BSs used to provide services. The reduction of the system capacity when BSs fails to provide services will be light. Moreover, our strategy can tolerate the wired link failures to enhance the system capacity. Key-Words: Hierarchical cellular network, speed-sensing, traffic-adaptation, fault-tolerance and handoff procedure