Optimum number of antennas for energy efficiency versus user location in massive MIMO systems

The large scale (massive) MIMO system is one of the candidate technologies for use in 5G due to its high energy efficiency (EE) and offered high data rate. In this paper, energy efficiency and proposed data rate of the large scale MIMO system in downlink mode are investigated according to the traffic load in the cellular network. In addition, three different user distribution models have been proposed for understanding the effect of users' position within the cell on EE. Under equal traffic load in all cells, simulations show that BS requires fewer antennas if most of the users are close to the cell center. As a result of simulations, it has been shown that the energy efficiency can be increased by changing the number of antennas that BS will use depending on the traffic load on the cell and user locations.