  In this paper, the outage performance of a two-tier heterogeneous mmWave
cellular networks employing joint spatial division and multiplexing (JSDM) is
investigated. It is assumed that macro base stations (BSs) equipped with a
large number of antennas and pico BSs equipped with single antenna serve users
simultaneously. The two-tier BSs and users are distributed according to
independent Poisson point processes (PPPs). Theoretical analysis of the
signal-to-interference-plus-noise ratio (SINR) outage probability of the
typical user is first provided. The all SINR outage probability of the two
tiers is then derived. Simulation results in accordance with theoretical
analysis demonstrating the performance improvement of two-tier networks compare
with the single-tier network are provided. By using the noise-limited
assumption for mmWave networks, a simpler expression to analyze the outage
performance is obtained.
