Cell-Free Massive MIMO With Low-Resolution ADCs Over Spatially Correlated Channels

Cell-free massive multiple-input multiple-output (MIMO) is a promising technology for future wireless networks. One main challenge of realizing practical cell-free massive MIMO is the high power consumption and huge hardware cost for employing high-resolution analog-to-digital converters (ADCs). To tackle this issue, a promising solution is to use low-resolution ADCs. In this paper, we investigate the cell-free massive MIMO system with low-resolution ADCs over spatially correlated channels. We generalize three levels of receiver cooperation and derive a tight closed-form expression of the spectral efficiency (SE) for a centralized receiver cooperation with large-scale fading decoding as a function of the resolution of ADCs. We also investigate the impact of spatial correlation magnitude on the sum SE. Moreover, we proposed a low-complexity power control method for maximizing the sum SE. Numerical results show that the centralized receiver cooperation needs more quantization bits to achieve the ideal performance and the proposed power control is efficient for improving the system performance.