On Improving Coverage and Connectivity in Mobile Wireless Sensor Networks

Dynamic deployment in wireless sensor networks (WSNs) aims to enhance network coverage and connectivity by redistributing nodes after initial random deployment. In this paper, we investigate the problem of dynamic deployment (DD) in WSNs using the Harmony Search (HS) optimization algorithm. In particular, we propose a family of five HS algorithms for DD that aim at maximizing both network coverage and connectivity; namely, Harmony Search-DD (HSDD), Improved HS-DD (IHS-DD), Global HS-DD (GHS-DD), Differential HS-Dynamic Deployment (DHS-DD), and Self adaptive HS-DD (SaHS-DD). In addition, the problem of continuously maintaining coverage under network topology change due to the loss of nodes either due to failure or power depletion is also investigated. To this end, we propose the Harmony Search - Continuous Coverage Optimization (HS-CCO) that attempts to achieve higher coverage under rapid node loss. The proposed algorithms are evaluated and compared under various network settings including dense and spare networks as well as networks with obstacles. Finally, the minimum number of nodes need to be moved in order to improve coverage is also studied and analyzed.