Interference alignment in frequency — A measurement based performance analysis

The idea of interference alignment (IA) has shown great promise in many theoretical studies. Yet it is not clear under what operating conditions it will perform better than traditional multiple access schemes under realistic network conditions. Here, we use measured channels to evaluate a number of different IA schemes and related methods, focusing on wideband single-antenna transmission, using frequency extensions for the IA. The radio channels were measured jointly from three base station sites in an urban macrocell scenario, over a 20 MHz bandwidth, allowing to emulate a scenario with 3 interfering cells (i.e. 3 interfering transmit/receive pairs). The numerical results show clear gains using IA related methods, compared to frequency planning with frequency reuse 3 and to uncoordinated transmission, even at low to moderate SNR.