Multi-user Downlink Beamforming using Uplink Downlink Duality with CEQs for Frequency Selective Channels

High-resolution fully digital transceivers are infeasible at millimeter-wave (mmWave) due to their increased power consumption, cost, and hardware complexity. The use of low-resolution converters is one possible solution realize architectures mmWave. In this paper, we consider a setting in which base station with constant envelope quantized (CEQ) digital-to-analog on each radio frequency chain communicates multiple single antenna users individual signal-to-quantization-plus-interference-plus-noise ratio (SQINR) constraints over selective channels. We first establish uplink downlink duality for the system CEQ OFDM-based transmission considered paper. Based principle, present multi-user multi-carrier beamforming allocation problem that maximizes minimum SQINR all sub-carriers. then per sub-carrier version originally proposed decouples sub-carriers OFDM waveform resulting smaller sub-problems can be solved parallel manner. Our numerical results based 3GPP channel models generated from xmlns:xlink="http://www.w3.org/1999/xlink">Quadriga demonstrate improvements terms ergodic sum rate state-of-the-art linear solutions. also show improved performance non-linear solutions coded bit error flexibility assigning user SQINRs built into framework.