Multiplexing-diversity tradeoffs in noncoherent massive MIMO systems

We consider an uncoded noncoherent uplink and downlink with a large antenna array at the base station. A ray tracing propagation model is assumed with knowledge at the base station of only the ray arrival angles and amplitudes. We identify the sources of performance degradation, quantify notions of diversity and multiplexing gains and present numerical results to demonstrate these gains. Our results indicate that in this noncoherent system, increasing the number of antenna elements increases multiplexing gain and reduces error rate. This contrasts with the fact that uncoded noncoherent systems yield no multiplexing gains in rich scattering.