Multilevel fault tolerance in infrastructure-oriented wireless networks: framework and performance evaluation

Significant advances have been made in the design and implementation of dependable systems and networks over the last several years. However, many wireless networks have not been designed for highly dependable operation owing to network cost and complexity, and a lack of regulatory requirements on wireless service quality. One way to address this significant challenge is by introducing fault tolerance; however, very limited work has been done so far in the fault-tolerant design of wireless networks. In this paper, we address how to utilize fault tolerance in the design of infrastructure-oriented wireless networks. More specifically, an architectural design scheme is presented for multilevel fault tolerance using adaptable building blocks. The scheme utilizes 'selective' redundancy at component, link and block levels and a fault-tolerant architecture for interconnection of building blocks. The design scheme has been implemented in both analytical and simulation models. The detailed performance results show that fault tolerance at component, link, block, and interconnection levels can significantly improve the overall dependability performance. One interesting observation is that, to achieve highest dependability, fault tolerance at link, component or block level is not suffficient and must be combined with the interconnection level fault-tolerance.