  Having lower quantization resolution, has been introduced in the literature,
as a solution to reduce the power consumption of massive MIMO and millimeter
wave MIMO systems. In this paper, we analyze bit error rate (BER) performance
of quantized uplink massive MIMO employing a few-bit resolution ADCs.
Considering Zero-Forcing (ZF) detection, we derive a closed-form quantized
signal-to-interference-plus-noise ratio (SINR) to achieve an analytical BER
approximation for coarse quantized M-QAM massive MIMO systems, by using a
linear quantization model. The proposed expression is a function of
quantization resolution in bits. We further numerically investigate the effects
of different quantization levels, from 1-bit to 4-bits, on the BER of three
modulation types of QPSK, 16-QAM, and 64-QAM. Uniform and non-uniform
quantizers are employed in our simulation.
  Monte Carlo simulation results reveal that our approximate formula gives a
tight upper bound for the BER performance of $b$-bit resolution quantized
systems using non-uniform quantizers, whereas the use of uniform quantizers
cause a lower performance for the same systems. We also found a small BER
performance degradation in coarse quantized systems, for example 2-3 bits QPSK
and 3-4 bits 16-QAM, compared to the full-precision (unquantized) case.
However, this performance degradation can be compensated by increasing the
number of antennas at the BS.
