Optimization of energy consumption in wireless sensor networks

In wireless networks, a widely studied approach is to minimize transmit powers subject to some quality-of-service constraints. Minimizing transmit powers however is not equivalent to minimizing the energy consumption. In wireless sensor networks that operate in a low-rate regime, the discrepancy between power consumption and the overall energy consumption is even more evident since the energy expenditure for signal processing cannot be neglected. The paper addresses the problem of minimizing the overall energy consumption in wireless networks, including the energy expenditure for hardware. The objective is to give some valuable insights into the problem. In particular, we point out basic properties of the optimal power allocation and discuss properties of the general energy minimization problem. Due to the complexity, we focus on the problem of finding a powertime tradeoff by determining the energy-optimal number of parallel data streams per link for a certain SIR requirement.