Energy-aware user scheduling for downlink multiuser-MIMO systems

In this paper we address the problem of designing a user selection algorithm in a multiuser multiple-input multiple-output downlink scenario. Linear precoding is adopted at the transmitter and, thus, the number of users to be served at each particular scheduling period is limited by the number of available transmit and receive antennas. The adopted scheduling criterion for the user selection is based on proportional fair criterion. The novelty relies on the fact that the users are considered to have a finite battery capacity and a harvesting source that allows them to recharge their batteries dynamically. The proposed user scheduler mechanism exploits not only the channel dynamics but also the battery fluctuations. We analyze how the intensity of the energy arrivals impacts the performance of the user scheduler. Simulations results show that the average long-term rates approach the requested quality of service if the scheduler controls the amount of energy that is being used by the terminals at each scheduling period.