A Study of TH Precoding System Performance with Imperfect Channel State Information

TH (Tomlinson-Harashima) precoding is an important nonlinear precoding method. In this paper, the bit error rate (BER) performance for the TH precoding system is investigated over time varying and dispersive Ricean fading channels. Assuming that there exists a certain delay introduced by the feedback channel, we first model the feedback error of channel station information (CSI) due to the feedback delay. Then the expression of the received signal over the time varying channel is derived. Finally, we analyze the power of interference signal resulting from the delay. Computer simulation shows that BER of the zero-forcing TH precoding system is inverse proportional to Ricean factor, and evident BER threshold occurs when the feedback delay is large.