Date Added: May 2012
Energy-efficient transmission is increasing in importance for wireless system design because of limited battery power in mobile devices. In this paper, the authors consider energy efficiency optimization in uplink virtual MIMO systems. First, accurate closed-form expressions are derived for the achievable energy efficiency for both Multi-User (MU) transmission mode and Single-User (SU) transmission mode, which are based on the ergodic throughput, transmit power and circuit power. Then, they describe the existence of unique globally optimal energy efficiency for SU and MU mode, respectively.