Power Minimization Strategies in Downlink MIMO-NOMA Systems

This paper studies the power minimization problem for non-orthogonal multiple access (NOMA) downlink systems, in which nodes are equipped with multiple antennas. We develop a joint power allocation and receive beamforming algorithm using the fixed-point update power allocation method under two types of channel state information (CSI). Particularly, we first assume that perfect CSI is available for the base station (BS) and the users, where a closed-form expression for every receive detection vector is derived. Then, we consider only channel distribution information (CDI) is known to the BS and the users, where one-dimension search and semi-definite programming (SDP) relaxation are used to derive the receive detection vectors.