On the Design of Quantization Functions for Uplink Massive MIMO with Low-Resolution ADCs

Quantization is the characterization of analogueto-digital converters (ADC) in massive MIMO systems. Thedesign of quantization function or quantization thresholds isfound to relate to quantization step, which is the factor thatadapts with the changing of transmit power and noise variance.With the objective of utilizing low-resolution ADC is reducingthe cost of massive MIMO, we propose an idea as if it isnecessary to have adaptive-threshold quantization function. Itis found that when maximum-likelihood (ML) is employed asthe detection method, having quantization thresholds fixed forlow-resolution ADCs will not cause significant performance loss.Moreover, such fixed-threshold quantization function does notrequire any information of signal power which can reduce thehardware cost of ADCs. Simulations have been carried out inthis paper to make comparisons between fixed-threshold andadaptive-threshold quantization regarding various factors