Asymptotic Analysis of Uplink Interference Alignment in Ricean Small Cells

In this work, we analyze the uplink capacity of a cellular Ricean channel system where clusters of small cell base stations are coordinated by a central processor. Two different scenarios dealing with intercluster interference are analyzed: global multicell joint decoding, where all base stations are connected to a central processor, and interference alignment that is used to mitigate intercluster interference. We analyze the impact of the Ricean factor on the clustered interference alignment performance. In this setting, we use recent results from random matrix theory, in particular the deterministic equivalent approach, to compute analytical expressions of the per-cell capacity. Simulation results corroborate the asymptotic analysis and show the performance of the interference alignment mitigation scheme in a Ricean channel multicell system. Interference alignment allows the per-cell capacity to achieve the benchmark, represented by the per-cell capacity in global multicell joint decoding. For high values of the Ricean factor, we observe that interference alignment has a better performance on intercluster interference.