Energy-Efficient Analog Combiner Design Using Low-Resolution Phase Shifters and Antenna Selection for mmWave D2D Communications

This study investigates the use of an analog combiner comprising low-resolution phase shifters (PSs) to suppress interference from other devices and improve the received signal power of interest in millimeter-wave device-to-device networks simultaneously. Unlike typical analog combining architectures with PS numbers equaling the number of receiver antennas, the number of PSs in this study is less than that of receiver antennas; this feature saves on equipment costs and improves power efficiency. We jointly optimize the receiver antenna selection and analog combiner design with low-resolution PSs to maximize the spectral efficiency of the resultant device. Because the formulated joint optimization problem is non-convex, we propose a probabilistic evolutionary optimization algorithm with an explicit expression for learning the tilting parameters of the designed sampling distribution. Simulation results demonstrate the excellent performance of the proposed algorithm compared with the semidefinite relaxation approach in terms of spectral and energy efficiency.