Lifetime Optimization through Uniform Energy Usage Among Sensors for Generic BS Location

Non-uniform energy usage among sensors due to varying distances from the base station makes some nodes to die early, thereby reducing the network´s lifetime drastically leaving considerable amount of residual energy in others. Performance optimization techniques that have recently been proposed include optimal transmission policies and dynamic relocation of the base station within the network area. Here we propose two transmission policies, namely, fixed hop size (FHS) and synchronous variable hop size (SVHS) transmissions considering generic location for the base station. We decompose the transmission distance of traditional multi hop protocol into two parts: ring thickness and hop size, and determine the optimal values of these parameters by formulating network lifetime as an optimization problem. Numerical results show that each of our policies perform substantially better in terms of network lifetime and energy usage distribution than the single hop and multi hop transmission policies irrespective of network size and distance of the base station from the network centre.