Analytical evaluation of post processing SIR for spatial diversity modes in cellular systems

This work characterizes the statistical distribution of the post processing Signal to Interference Ratio (SIR) for a multi-cellular system employing different spatial diversity modes such as receive-maximal ratio combining, space time block coding, and closed loop singular value decomposition based beamforming. The framework used for analysis considers the combined effect of distance dependent pathloss, shadowing, and small scale fading. It is shown that for all the above mentioned spatial modes the post processing SIR for a single link follows lognormal distribution. Furthermore, the downlink SIR of a cell with uniform user distribution has been evaluated semi-analytically. All the analytically obtained results are validated through extensive Monte Carlo simulations.