On power reduction strategies for the multi-user downlink with decentralized receivers

For the multi-user-downlink with decentralized receivers we compare non-linear precoding schemes a la Costa\´s "Writing on Dirty Paper" with linear precoding. We show that suboptimal schemes like standard ranked known interference (RKI) and Tomlinson-Harashima-precoding (THP) can achieve a considerable transmit power reduction compared to linear channel inversion (LCI) or joint transmission (JT) and that joint transmit power further more, especially in bad conditioned channels or if the SINR requirements at the receiver are relaxed.