A comparative study of energy efficiency between MIMO and SISO based LTE RANs

A Novel method to evaluate the energy efficiency of different MIMO schemes is proposed in this paper, where the LTE radio base station power consumption is estimated by using an accurate power consumption model. The energy consumption gain (ECG) is used as a metric, and it is calculated for a MIMO base station with reference to a SISO base station. The results show that the MIMO base station cannot be more energy efficient than the SISO base station if the MIMO overhead power increases by more than 20%. The energy efficiency of MIMO base station can be improved by adapting the number of active transmit antennas according to the offered traffic load intensity. Moreover, the energy efficiency of an LTE RAN is evaluated when the network has been dimensioned by assuming MIMO base stations. The obtained results show that when spatial multiplexing schemes are assumed, and under the same requirements of coverage and traffic load, the MIMO RAN can be more energy efficient than the SISO RAN, even if the MIMO base station overhead power is increased by 60%.