Throughput of two-tier heterogeneous wireless networks with interference coordination

Two-tier heterogeneous wireless networks are considered in this paper where nodes in the first tier are distributed as a Poisson Point Process (PPP). Nodes in the second tier are distributed as a Poisson Clustered Process (PCP). Nodes in the second tier have imperfect channel state information (CSI) of the first tier node whose Voronoi cell they are in. On one hand, cross-tier interference is coordinated to the second tier nodes by interference alignment (IA) approach, where we strike a balance between increasing the number of data streams and increasing signal-to-interference (SIR) ratio at each data stream. On the other hand, the remaining interference is modelled by stochastic geometry and analytic expressions of throughput are derived. Monte Carlo simulations validate our expressions and show the gain brought by the interference coordination approach.