  In this paper, we consider the downlink of large OFDMA-based networks and
study their performance bounds as a function of the number of - transmitters
$B$, users $K$, and resource-blocks $N$. Here, a resource block is a collection
of subcarriers such that all such collections, that are disjoint have
associated independently fading channels. In particular, we analyze the
expected achievable sum-rate as a function of above variables and derive novel
upper and lower bounds for a general spatial geometry of transmitters, a
truncated path-loss model, and a variety of fading models. We establish the
associated scaling laws for dense and extended networks, and propose design
guidelines for the regulators to guarantee various QoS constraints and, at the
same time, maximize revenue for the service providers. Thereafter, we develop a
distributed resource allocation scheme that achieves the same sum-rate scaling
as that of the proposed upper bound for a wide range of $K, B, N$. Based on it,
we compare low-powered peer-to-peer networks to high-powered single-transmitter
networks and give an additional design principle. Finally, we also show how our
results can be extended to the scenario where each of the $B$ transmitters have
$M (>1)$ co-located antennas.
