Interference mitigation based on precoded SRS

This paper illustrates an interference mitigation method based on the estimation of an equivalent channel using Sounding Reference Signal (SRS) sequences in Time Division Duplex (TDD) multi-cell systems. The key idea is to precode the SRS sequence with a pre-coder that is computed based on the choice made by the User Equipment (UE) of its preferred signal subspace. Assuming channel reciprocity in TDD systems, the interfering Base Stations (BSs) can estimate the equivalent precoded channels and avoid sending signal to their own UE in that direction, thus reducing interference, without any need for feedback. We investigate this method with varying degrees of available perfect channel state information at the transmitter and show that it can surpass a Maximum-Ratio-Transmission (MRT) transceiver.