Energy Efficient Precoder Design and Power Allocation for a Low Complexity mmWave System

In this paper, we investigate the design of a system that is both energy efficient and has low hardware complexity. A fully analog architecture is considered in the system model to reduce the hardware complexity. The low beamforming gain of a fully analog system is improved by using double phase shifters at each antenna element, and multi-user(MU) transmission is enabled by using non-orthogonal multiple access(NOMA) as the radio access technique. The problem is formulated as an appropriately constrained energy efficiency(EE) maximization problem. This formulation is non-convex because it is fractional. To simplify this into a convex problem, we propose to use a quadratic transform. We then present an iterative algorithm to obtain optimal beamformer and power allocation. Finally, we evaluate the proposed system model via simulations.