Enhanced interference whitening for co-channel interference suppression

The co-channel interference (CCI) has become a major throughput-limiting factor for cell-edge users in the modern cellular systems such as the Long Term Evolution (LTE) network. Spatial interference whitening (IW) is an effective low-complexity linear method to suppress colored spatial interference in a MIMO setup. However, for CCIs using Alamouti´s type of SFBC (space-frequency block coding) transmission, the conventional per-subcarrier IW fails to exploit the SFBC structure and thus is suboptimal. To address that, we propose an optimal method called enhanced interference whitening (eIW). eIW works on a properly combined augmented MIMO model for two subcarriers involved in the same SFBC encoding block and thus can fully exploit the interference structure. Simulations show that if the interfering cell uses SFBC significant performance gains can be achieved by eIW no matter whether or not SFBC is used for the serving cell.