Energy efficient generalised selection combining scheme considering circuit power dissipation

Increasing the number of transmit antennas can improve the diversity gain of the system, and accordingly reduce the transmit power dissipation. However, the high circuit power dissipation incurred cannot be ignored. Generalised selection combining, which could provide a certain spatial diversity in the transmit diversity systems, performs a good balance between system performance and practical implementation cost. In this study, the authors propose an energy efficient generalised selection combining (EE-GSC) scheme which obtains improved transmitter energy efficiency (EE) by providing a best tradeoff between the diversity gain and the circuit power dissipation of multiple antennas. Based on the classical results of order statistics, a theoretical analysis of EE-GSC performance is carried out in detail over Rayleigh fading channels. Based on this analysis, the average number of active branches as well as the average power dissipation of the proposed scheme is also derived. Numerical results are also given to further illustrate the EE performance of the proposed scheme.