Energy Consumption Analysis of Energy Harvesting Systems with Power Grid

Energy Harvesting (EH) is an indispensable technology for future wireless communication systems due to its potential in saving nonrenewable energy and making the communication environmentally friendly. However, due to the unpredictable and intermittent nature of the external energy arrivals, communication systems solely powered by harvested energy can not guarantee the delivery of reliable and uninterrupted services. Consequently, having stable power supply from power grid is still of great importance in EH communication systems. In this letter, we consider a wireless communication system powered by both power grid energy and harvested energy. Specifically, we propose two strategies depending on how the harvested energy is used, and investigate the average energy consumed from the power grid in each case. The major contribution of this letter is the derivation of recursive expressions for the grid energy consumption in hybrid-energy supply communication systems, which may provide an useful tool for transmission scheme designs.