Interference alignment using shadow channel

Abstract

The time variance of a channel is exploited in interference alignment techniques. However, in the case of static channels, these interference alignment techniques do not hold, specifically for single-antenna systems. In this paper, we introduce simple data processing techniques that enable us to create the effect of a time varying channel from the underlying static channel. We call this channel the shadow channel. We exploit the time-varying nature of the relative channels introduced by the shadow channel for interference alignment. We demonstrate the throughput benefits of this interference alignment technique for different topologies. This technique can be thought of as operating over the two dimensions of the complex space of typical communication systems. In this paper, we present the feasibility of interference alignment techniques for single antenna nodes in static channel. We establish bound on the throughput gain due to this technique. Finally, we implement interference alignment over the shadow channel on the NI PXIe 1082 based software defined radio. We achieve throughput gains of upto 1.44X over TDMA systems using this interference alignment technique and upto 1.61X when this technique is coupled with interference cancellation.