MIMO Interference Alignment in Random Access Networks


Behrang Nosrat-Makouei, Radha Krishna Ganti, Jeffrey G. Andrews, and Robert W. Heath, Jr.


Proceedings of 45th Annual Asilomar Conference on Signals, Systems, and Computers, pp. 641 - 645, Pacific Grove, CA, Nov. 2011.


In this paper we analyze a multiple-input-multiple-output interference channel where nodes randomly distributed on a plane utilize interference alignment to reduce the point-to-point outage. We model the spatial distribution of the nodes as a spatial Poisson cluster point process with equal sized clusters. Each cluster uses intra-cluster interference alignment to suppress interference. We link the accuracy of channel state information to the distance between the nodes, i.e., for a fixed SNR, the quality of CSI degrades with increasing distance. Accounting for the inter-cluster unaligned interference, we compare intra-cluster interference alignment with open-loop spatial multiplexing. In our analysis we find common system setups where the benefits of using interference alignment over spatial multiplexing degrade the most due to the imperfect channel state information.