Interactive interference alignment

We study interference channels (IFC) where interaction among sources and destinations is enabled, e.g., both sources and destinations can talk to each other. The interaction can come in two ways: 1) for half-duplex radios, destinations can talk back to sources using either simultaneous out-of-band (white spaces) transmission or in-band half-duplex transmission; 2) for full-duplex radios, both sources and destinations can transmit and listen in the same channel simultaneously. The flexibility afforded by interaction among sources and destinations allows for the derivation of interference alignment (IA) strategies that have desirable “engineering properties”: insensitivity to the rationality or irrationality of channel parameters, small block lengths and finite SNR operations. We show that for several classes of interference channels the interactive interference alignment scheme can achieve the optimal degrees of freedom.