  We consider a stylized stochastic model for a wireless CSMA network.
Experimental results in prior studies indicate that the model provides
remarkably accurate throughput estimates for IEEE 802.11 systems. In
particular, the model offers an explanation for the severe spatial unfairness
in throughputs observed in such networks with asymmetric interference
conditions. Even in symmetric scenarios, however, it may take a long time for
the activity process to move between dominant states, giving rise to potential
starvation issues. In order to gain insight in the transient throughput
characteristics and associated starvation effects, we examine in the present
paper the behavior of the transition time between dominant activity states. We
focus on partite interference graphs, and establish how the magnitude of the
transition time scales with the activation rate and the sizes of the various
network components. We also prove that in several cases the scaled transition
time has an asymptotically exponential distribution as the activation rate
grows large, and point out interesting connections with related exponentiality
results for rare events and meta-stability phenomena in statistical physics. In
addition, we investigate the convergence rate to equilibrium of the activity
process in terms of mixing times.
