Energy-efficient communication is an important requirement for mobile devices, as the battery technology has not kept up with the growing requirements stemming from ubiquitous multimedia applications. This paper considers energy-efficient transmission schemes in cooperative cellular systems with unbalanced traffic between uplink and downlink. Theoretically, we derive the optimal transmission data rate, which minimizes the total energy consumption of battery-powered terminals per information bit. The energy-efficient cooperation regions are then investigated to illustrate the effects of relay locations on the energy-efficiency of the systems, and the optimal relay location is found for maximum energy-efficiency. Finally, numerical results are provided to demonstrate the tradeoff between energy-efficiency and spectral efficiency.
@article{arxiv.1009.0074,
title = {Energy-Efficient Transmission Schemes in Cooperative Cellular Systems},
author = {Wei Yang and Lihua Li and Ying Wang and Wanlu Sun},
journal= {arXiv preprint arXiv:1009.0074},
year = {2012}
}