A Novel Frequency-Domain Implementation of Tomlinson-Harashima Precoding for SC-FDMA

There is considerable interest in the use of single carrier frequency division multiple access (SC-FDMA) as the uplink transmission scheme in the 3GPP Long Term Evolution standard. This interest is justified by the inherent single carrier structure of SC-FDMA, which results in reduced sensitivity to phase noise and a lower peak-to-average power ratio (PAPR) compared to orthogonal frequency division multiple access. This, consequently, makes it more attractive for low cost devices with limited transmit power. In this paper we demonstrate how precoding the uplink transmission is an alternative signal processing technique to equalization in order to combat the frequency selective nature of the propagation channel. The frequency-domain implementation of Tomlinson-Harashima precoding (THP) for uplink SC-FDMA is proposed. We investigate the BER performance and the PAPR characteristics of the preceded SC-FDMA waveform for ZF and MMSE based THP. Results reported here show that the MMSE-THP outperforms the ZF-THP in terms of BER performance and PAPR.