1-bit Nonlinear Mapping Precoder for Downlink Massive MU-MIMO Systems

This paper studies a downlink massive multiuser multiple-input multiple-output system with PSK modulation, where the base station employs 1-bit digital-to-analog converters (DACs). We first exploit the concept of constructive interference (CI) to express the received PSK signal in terms of the coordinate vector. With the coordinate vector, we construct a nonlinear mapping (NM) function in which the function value is small when the coordinate coefficient is large. Then we present a low-complexity NM-MinSum algorithm to solve a single-objective optimization problem which minimizes the sum of the NM function of the coordinate vector. Further, we propose a two-objective optimization problem and develop the NM-DualMax algorithm to find its solution. The numerical results show the proposed algorithms achieve comparable performance to the existing nonlinear precoding approaches.