  This paper considers uplink massive multiple-input multiple-output (MIMO)
systems with lowresolution analog-to-digital converters (ADCs) over Rician
fading channels. Maximum-ratio-combining (MRC) and zero-forcing (ZF) receivers
are considered under the assumption of perfect and imperfect channel state
information (CSI). Low-resolution ADCs are considered for both data detection
and channel estimation, and the resulting performance is analyzed. Asymptotic
approximations of the spectrum efficiency (SE) for large systems are derived
based on random matrix theory. With these results, we can provide insights into
the trade-offs between the SE and the ADC resolution and study the influence of
the Rician K-factors on the performance. It is shown that a large value of
K-factors may lead to better performance and alleviate the influence of
quantization noise on channel estimation. Moreover, we investigate the power
scaling laws for both receivers under imperfect CSI and it shows that when the
number of base station (BS) antennas is very large, without loss of SE
performance, the transmission power can be scaled by the number of BS antennas
for both receivers while the overall performance is limited by the resolution
of ADCs. The asymptotic analysis is validated by numerical results. Besides, it
is also shown that the SE gap between the two receivers is narrowed down when
the K-factor is increased. We also show that ADCs with moderate resolutions
lead to better energy efficiency (EE) than that with high-resolution or
extremely low-resolution ADCs and using ZF receivers achieve higher EE as
compared with the MRC receivers.
