Energy efficient power allocation in a multi-radio mobile device with wireless energy harvesting

In this paper, we consider the operation of a mobile multi-radio wireless device, which may simultaneously utilize several radio access technologies when transmitting its data. Whereas the use of multiple radios does improve network capacity and user connectivity experience, it also results in a significant growth of device energy demands. To compensate for it, the device may leverage the excess availability of wireless energy present in its local environment through energy harvesting. Therefore, we envision that wireless power energy harvesting would be increasingly employed in future multi-radio mobile equipment and propose a provably optimal (in the energy efficiency sense) transmission power allocation scheme at the device, mindful of the available radio access networks. Consequently, our scheme delivers an upper bound on energy efficiency among all practical power control mechanisms and thus becomes an important consideration for heterogeneous networks.