Coordinated Beamforming with Dynamic Clustering: A Stochastic Geometry Approach

This paper characterizes the performance of coordinated beamforming with dynamic clustering. A downlink cellular model based on stochastic geometry is put forth to analyze the performance of such base station (BS) coordination strategy. Analytical expressions for the complementary cumulative distribution function (CCDF) of the instantaneous signal-to-interference ratio (SIR) are derived in terms of relevant system parameters, chiefly the number of coordinated BSs, the number of antennas, and the path-loss exponent. Utilizing this CCDF, with pilot overheads further incorporated into the analysis, we formulate the computation of the number of coordinated BSs that maximizes the spectral efficiency for a given fading coherence. The results make precise the intuition that the slower the fading, the more beneficial the coordination. Simulation results verify the exactness of the SIR distribution derived for stochastic geometries, which is further compared with the corresponding distribution for a deterministic grid model.