On optimal signaling schemes of 1-bit ADC in non-coherent blockage fading

Tóm tắt

Low-resolution analog-to-digital converters (ADCs), especially 1-bit quantizers, enable power- and cost-efficient wideband, large-scale MIMO. We study non-coherent fast-fading channels with probabilistic line-of-sight (LoS) blockage under 1-bit output quantization. The model randomly switches between Rayleigh (A = 0) and Rician (A = 1) fading, capturing environments where the LoS path intermittently appears. Without CSI at either end, we analyze mutual information and characterize the capacity-achieving input distribution. We prove that any optimal input exhibits π/2-rotational symmetry and derive necessary and sufficient Kuhn–Tucker conditions for optimality. Simulations show that the optimum tends to a four-point square constellation whose orientation aligns with the LoS phase when present. These results quantify the impact of probabilistic LoS on capacity and guide input design for energy-constrained, dynamically fading systems.