Optimizing Energy Consumption in Terahertz Band Nanonetworks

In this paper, we develop a technique for achieving the maximum utilization of harvested energy in perpetual wireless nanonetworks, where nanonodes communicate in the THz frequency band. Because of their nano-scale sizes, nanonodes cannot store large amounts of energy. Compounding the problem, the arrival of energy is not constant, but follows a stochastic process. Therefore, an optimum design for the consumption of this limited amount of energy is required. We model the problem as a Markov decision process, where we include the energy for both reception and transmission of packets. We analyze the performance of the energy harvesting and consumption processes for very low energy harvesting rates and small energy storage capacity. We compare the performance of the optimal policy with intuitive energy consumption policies. Next, since solving an optimized problem of this sort is too compute-intensive for nanonodes with limited resources, we propose a light-weight heuristic method that can perform close to optimal. Simulation results show that our heuristic model and the optimal model can serve as a framework for the design of nanonodes that operate in low rate stochastic energy harvesting conditions with limited energy storage.