  The one-bit spatial Sigma-Delta concept has recently been proposed as an
approach for achieving low distortion and low power consumption for massive
multi-input multi-output systems. The approach exploits users located in known
angular sectors or spatial oversampling to shape the quantization noise away
from desired directions of arrival. While reducing the antenna spacing
alleviates the adverse impact of quantization noise, it can potentially
deteriorate the performance of the massive array due to excessive mutual
coupling. In this paper, we analyze the impact of mutual coupling on the uplink
spectral efficiency of a spatial one-bit Sigma-Delta massive MIMO architecture,
and compare the resulting performance degradation to standard one-bit
quantization as well as the ideal case with infinite precision. Our simulations
show that the one-bit Sigma-Delta array is particularly advantageous in
space-constrained scenarios, can still provide significant gains even in the
presence of mutual coupling when the antennas are closely spaced.
