Interference alignment for clustered multicell joint decoding

Multicell joint processing has been proven to be very efficient in overcoming the interference-limited nature of the cellular paradigm. However, for reasons of practical implementation global multicell joint decoding is not feasible and thus clusters of cooperating Base Stations have to be considered. In this context, intercluster interference has to be mitigated in order to harvest the full potential of multicell joint processing. In this paper, interference alignment is investigated as a means of intercluster interference mitigation and its performance is compared to global multicell joint processing. Both scenarios are modelled and analyzed using the per-cell ergodic sum-rate capacity as a figure of merit. In this process, a number of theorems are derived for analytically expressing the asymptotic eigenvalue distributions of the channel covariance matrices. The analysis is based on principles from Free Probability theory and especially properties in the R and Stieltjes transform domain.