Existence of dumb nodes in stationary wireless sensor networks

Wireless sensor networks (WSNs), which are typically autonomous and unattended, require energy-efficient and fault-tolerant protocols to maximize the network lifetime and operations. In this work, we consider a previously unexplored aspect of the sensing nodes - dumb behavior. A sensor node is termed as "dumb", when it can sense its surroundings, but cannot communicate with its neighbors due to shrinkage in communication range attributed to adverse environmental effects and can behave normally in the presence of favorable environment. As a result of this temporary behavior, a node may get isolated from the network when adverse environmental effects are present, but re-connects with the network with the resumption of favorable environmental conditions. We consider the effects of dumb nodes on the, otherwise, energy-efficient stationary WSNs having complete network coverage achieved using sufficient number of activated sensor nodes. While the presence of redundancy in the deployment of nodes, or the number of active nodes can guarantee communication opportunities, such deployment is not necessarily energy-efficient and cost-effective. The dumb behavior of nodes results in wastage of power, thereby reducing the lifetime of a network. Such effects can be detrimental to the performance of WSN applications. The simulation results exhibit that the network performance degrades in the presence of dumb nodes in stationary WSNs.