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Journal of Optimization
Volume 2013 (2013), Article ID 636529, 6 pages
Research Article

Power Optimization of Tilted Tomlinson-Harashima Precoder in MIMO Channels with Imperfect Channel State Information

1Malek Ashtar University of Technology, Tehran, Iran
2Tabriz University, Tabriz, Iran
3Iran University of Science and Technology (IUST), Tehran, Iran

Received 28 January 2013; Revised 15 April 2013; Accepted 27 April 2013

Academic Editor: Kai-Kit Wong

Copyright © 2013 Hossein Khaleghi Bizaki et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper concentrates on the designing of a robust Tomlinson-Harashima Precoder (THP) over multiple-input multiple-output (MIMO) channels in wireless communication systems with assumption of imperfect channel state information (CSI) at the transmitter side. With the assumption that the covariance matrix of channel estimation error is available at the transmitter side, we design a THP that presents robustness against channel uncertainties. In the proposed robust THP, the transmit power is further minimized by using the Tilted constellation concept. This power minimization reduces the interchannel Interference (ICI) between subchannels and, furthermore, recovers some part of the THP's power loss. The bit error rate (BER) of the proposed system is further improved by using a power loading technique. Finally, the simulation results compare the performance of our proposed robust THP with a conventional MIMO-THP.