A novel performability assessment approach of Mobile Ad Hoc Network

In Mobile Ad hoc Networks (MANETs), system performance degrades when some switching nodes and/or communication links fail to operate. As a result, the performability (performance reliability) assessment of MANETs is very important. However, because of the impact of dynamic topology, the traditional system performability analysis methods, such as Dynamic Fault Tree (DFT) and Dynamic Reliability Block Diagrams (DRBD), can´t be applied to evaluate MANETs. In this paper, we propose a hierarchical modeling approach for performability analysis of MANETs with repairable components. The lower level network components are described by Markov Reward Chains (MRC), which allow complex component failure/repair behaviors to be modeled. At the upper level, the MANET is considered as a small-world network, and the characteristic path length of the network is used to ascertain the global status of the network. The proposed hierarchical modeling approach combines the characteristics of small-world network and Markov chain theories together. A specific case of MANET is presented to support our approach in this paper. What´s more, we build the same network scenario in OPNET and implement some simulation experiments. The results show a very good correspondence of performability analysis between our approach and the OPNET simulation.