MIMO strategies for energy efficient transmission in LTE pico-cell environments

Mobile data traffic is increasing at an unprecedented rate. To cope with this, operators are deploying small base station sites to cover hot spots. However, this also increases the total network energy expenditure and carbon footprint. As a consequence, improving the energy efficiency of small base stations remains a hot topic. In this paper energy efficient transmission in LTE pico-cell environments is addressed aiming at providing a basis for LTE networks optimization and carbon footprint reduction. MIMO is studied from an energy efficiency point of view rather than from an increased datarates perspective as usually found in literature. Additionally, duty-cycling in time and frequency is also considered, hence, improving the amount of power reduction that can be achieved. Globally, a factor of twelve times variation between the worst-case power consumption and the optimally selected MIMO mode is observed in pico-cells.