Energy-Efficient Operation of a Mobile User in a Multi-tier Cellular Network

In this paper, we propose a new power control scheme suitable for a multi-tier wireless network. It maximizes the energy-efficiency of a mobile device transmitting on several communication channels while at the same time ensures the required minimum quality of service. As the result, a good compromise between improving the data rate and extending the battery lifetime is provided. In order to enable energy-efficiency maximization, we formulate an optimization problem basing on the Shannon’s capacity formula. The optimal transmit power is thus obtained from the direct solution of this optimization problem under several practical constraints, such as minimum bitrate and maximum transmit power. In the second part of the paper, we apply extensive simulations to calibrate the key parameters of our optimization framework. The numerical results suggest the benefit of the proposed analytical solution by comparing it against intuitive (heuristic) power control strategies.