Optimizing energy efficiency of a multi-radio mobile device in heterogeneous beyond-4G networks

In this paper, we address the operation of a multi-radio mobile device in heterogeneous wireless deployments. We assume that such a device may efficiently control its radio interfaces when using the available radio access technologies. In particular, we investigate the potential of flexible transmit power allocation and develop a provably optimal power control scheme that strictly maximizes the energy efficiency of the mobile device, while at the same time satisfies the minimum required level of the user data rate. When compared against simpler (heuristic) power control strategies, our solution always demonstrates the best energy efficiency of the multi-radio device by enabling collaborative operation between several radio technologies, which makes it a useful benchmark for the future integrated beyond-4G wireless networks.