  We analyze the delay performance of small cell networks operating under
random scheduling (RS) and round robin (RR) protocols. Based on stochastic
geometry and queuing theory, we derive accurate and tractable expressions for
the distribution of mean delay, which accounts for the impact of random traffic
arrivals, queuing interactions, and failed packet retransmissions. Our analysis
asserts that RR outperforms RS in terms of mean delay, regardless of traffic
statistic. Moreover, the gain from RR is more pronounced in the presence of
heavy traffic, which confirms the importance of accounting fairness in the
design of scheduling policy. We also find that constrained on the same delay
outage probability, RR is able to support more user equipments (UEs) than that
of RS, demonstrating it as an appropriate candidate for the traffic scheduling
policy of internet-of-things (IoT) network.
