On the Performance of Cell -Free Massive MIMO with One-Bit ADCs and DACs

In this paper, we consider a downlink cell-free massive multiple-input multiple-output (mMIMO) system with conjugate beamforming precoder, where each access point (AP) is equipped with one-bit analog-digital converters (ADCs) and digital-analog converters (DACs) and each user is equipped with one-bit ADCs. Based on the Bussgang decomposition theory, we derive a tight approximate rate expression, which enables us to investigate the design issues of the number of antenna arrays and the quantization configurations. Owing to the undesired channel estimation error and the irrelevant quantization interference, the triple-quantized cell-free mMIMO system suffers from a significant performance degradation compared to the case without any quantization. In addition, our simulation results reveal that the downlink rate performance is primarily limited by the ADCs’ resolution at the users and equipping the users with one-bit ADCs to reduce the power consumptions and energy costs in cell-free mMIMO is not advisable.