  In this paper we consider the uplink of a massive MIMO communication system
using 5G New Radio-compliant multiple access, which is to co-exist with a radar
system using the same frequency band. We propose a system model taking into
account the reverberation (clutter) produced by the radar system at the massive
MIMO receiver. Then, we propose several linear receivers for uplink
data-detection, ranging by the simple channel-matched beamformer to the
zero-forcing and linear minimum mean square error receivers for clutter
disturbance rejection. Our results show that the clutter may have a strong
effect on the performance of the cellular communication system, but the use of
large-scale antenna arrays at the base station is key to provide increased
robustness against it, at least as far as data-detection is concerned.
