  Internet-of-things (IoT), with the vision of billions of connected devices,
is bringing a massively heterogeneous character to wireless connectivity in
unlicensed bands. The heterogeneity in medium access parameters, transmit power
and activity levels among the coexisting networks leads to detrimental
cross-technology interference. The stochastic traffic distributions, shaped
under CSMA/CA rules, of an interfering network and channel fading makes it
challenging to model and analyze the performance of an interfered network. In
this paper, to study the temporal interaction between the traffic distributions
of two coexisting networks, we develop a renewal-theoretic packet collision
model and derive a generic collision-time distribution (CTD) function of an
interfered system. The CTD function holds for any busy- and idle-time
distributions of the coexisting traffic. As the earlier studies suggest a
long-tailed idle-time statistics in real environments, the developed model only
requires the Laplace transform of long-tailed distributions to find the CTD.
Furthermore, we present a packet error rate (PER) model under the proposed CTD
and multipath fading of the interfering signals. Using this model, a
computationally efficient PER approximation for interference-limited case is
developed to analyze the performance of an interfered link.
