Residual Energy-Based Strategies for the Transmission Probability and Duty-Cycle Selection in Wireless Sensor Networks

WSNs are complex systems that are mainly limited by the battery life of the nodes in order to have an adequate performance. During the operation of the system, it is not uncommon to have a portion of nodes with low energy levels while other nodes have high energy levels. Nodes with very low residual energy must reduce their energy consumption since their operational lifetime is almost over. In this paper, we consider cluster-based WSNs for the event detection where there is a high concentration of high energy nodes and low concentration of low energy nodes. Building on this, we propose extending the battery life of low energy nodes in both the cluster formation and the steady-state phases. For the former, energy efficiency is achieved by means of assigning prioritized access to the shared channel to low energy nodes while delaying the contention access of high energy nodes which can support higher number of collisions before energy depletion. For the latter, we consider the duty-cycle of nodes where the sleep and active modes have dwelling times related to their residual energy levels. The system and the impact of the proposed residual energy-based mechanisms are mathematically evaluated using Markovian models.