Secondary User Interference Characterization for Spatially Random Underlay Networks With Massive MIMO and Power Control

In an underlay (secondary) network, the receiver nodes are subject to both primary and intra-underlay interference. What are the characteristics of this interference when considering the use of massive multiple-input multiple-output (MIMO) systems with pilot contamination, path-loss-inversion power control, receiver association policies, spatially random nodes, and propagation characteristics with power-law path loss and Rayleigh fading? To answer this question, we derive the average and the moment generating function of the aggregate interference and its average due to both primary and underlay transmissions from nodes modeled as Poisson point processes and analyze how the interference impacts the outage performance of an underlay receiver. Our analysis considers all of the above factors and both single antenna type and massive MIMO base stations. We show that massive MIMO improves the outage performance, and a higher path loss exponent reduces the outage probability. This is in contrast to single antenna systems where a higher path loss exponent increases the outage. Furthermore, it is shown that the different node densities and power thresholds significantly affect the outage performance.