Simultaneous wireless information and power transfer in multiuser MIMO systems

In this paper, we focus on a broadcast multiuser multiple-input multiple-output (MIMO) system in a network with short links. In this scenario we consider that some terminals harvest power and, thus, recharge their batteries, through wireless power transfer from the transmitter while others are simultaneously being served with data transmission. We assume that the nodes are battery powered devices and, consequently, such solution provides a convenient energy supply. The sum-rate for the users being served with data is considered as the optimization policy where power harvesting per user constraints are taken into account. We provide the optimal structure of the resulting transmit covariance matrices and precoders for the users in the general case (i.e., in scenarios where both types of nodes are present in the network) and we also study the case where only harvesting nodes are to be served. Finally, we analyze and characterize the fundamental tradeoff between the data transmission sum-rate and the powers harvested by the network nodes using the concept of the rate-energy (R-E) region.