Analysis of Topological Characteristics of Unreliable Mobile Wireless Ad Hoc Network

The paper presents a simulation-based study of topological characteristics of a mobile wireless ad-hoc network with unreliable nodes. The characteristics studied are connectivity, coverage, maximum inter-node distance and node degree. Knowledge of these characteristics aids in the design of new distributed protocols as well as in predicting the performance and robustness of current protocols executing on the network. The paper presents intelligent mobility algorithms which aim to achieve desired levels of the output parameter values. The environment is unreliable with nodes prone to failures, in either permanent or transient manner. The nodes also have constraints on their transmission ranges arising from constraints on the power consumption. In this paper, we study the behavior of the output measures with increasing number of nodes in the topology and find that coverage is the primary determinant of the number of nodes. The behavior is studied successively under failure-free conditions, and with node failures. The results bring out cutoff points for ratio of permanent to transient failures and mean time to failure (MTTF) beyond which the QoS for the output measures degrades sharply. We also present a theoretical derivation of the sufficient condition for connectivity and coverage in the network and validate the result through simulation.