  The spatial correlations in transmitter node locations introduced by common
multiple access protocols makes the analysis of interference, outage, and other
related metrics in a wireless network extremely difficult. Most works therefore
assume that nodes are distributed either as a Poisson point process (PPP) or a
grid, and utilize the independence properties of the PPP (or the regular
structure of the grid) to analyze interference, outage and other metrics.
But,the independence of node locations makes the PPP a dubious model for
nontrivial MACs which intentionally introduce correlations, e.g. spatial
separation, while the grid is too idealized to model real networks. In this
paper, we introduce a new technique based on the factorial moment expansion of
functionals of point processes to analyze functions of interference, in
particular outage probability. We provide a Taylor-series type expansion of
functions of interference, wherein increasing the number of terms in the series
provides a better approximation at the cost of increased complexity of
computation. Various examples illustrate how this new approach can be used to
find outage probability in both Poisson and non-Poisson wireless networks.
