On Performance of Quantized Transceiver in Multiuser Massive MIMO Downlinks

Low-resolution digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) are considered to reduce cost and power consumption in multiuser massive multiple-input multiple-output. Using the Bussgang theorem, we derive the asymptotic downlink achievable rate with respect to the resolutions of both DACs and ADCs, i.e., b
_DA
and b
_AD
, under the assumption of large antenna number N, and fixed user load ratio β. We characterize the rate loss caused by finite-bit-resolution converters and reveal that the quantization distortion is ignorable at low signal-to-noise ratio (SNR) even with low-resolution converters at both sides. While for maintaining the same rate loss at high SNR, it is discovered that one-more-bit DAC resolution is needed when more users are scheduled with β increased by four times. More specifically for one-bit rate loss requirement, b
_DA
can be set by Γb
_AD
+ (1/2) log β⌉ given b
_AD
. Similar observations on ADCs are also obtained with numerical verifications.