Frequency Diversity versus Channel Training in Latency-Constrained Massive MIMO

The effect of correlation between neighboring resource blocks (RBs) in the outage probability performance of OFDM-based Massive MIMO systems is investigated. An upper bound on the outage probability, which is the relevant performance metric for latency-constrained communication, of two operations that exploit this correlation structure is derived and compared with the base scenario of orthogonal communication, where the correlation is ignored. It is observed that substantial outage probability improvement can be reaped already when moderate correlation is present. Closed-form upper and lower bounds on the investigated outage probability are derived. The bounds are shown to be tight for a wide range of system parameters and can be used to draw insights on the optimal design of latency-constrained Massive MIMO systems.