Frequency-domain precoding for single carrier frequency-division multiple access

At present there is considerable interest in the use of single carrier frequency-division multiple access. This interest is justified by the inherent single carrier structure of the SC-FDMA scheme, which is more robust against phase noise and has a lower peak-to-average power ratio than orthogonal frequency-division multiple access. This consequently makes it more attractive for uplink transmission from low-cost devices with limited transmit power. SC-FDMA commonly makes use of frequency domain linear equalization in order to combat the frequency selectivity of the transmission channel. Frequency domain decision feedback equalization, composed of a frequency domain feed forward filter and a time domain feedback filter, outperforms LE due to its ability to cancel precursor echoes. Although these solutions suffer from error propagation, results show that DFE still offers a significant performance gain over conventional LE for uncoded SC-FDMA. In this article we show how precoding can be used on the uplink of the LTE standard to overcome the frequency selective nature of the radio channel. We propose a frequency domain implementation of Tomlinson- Harashima precoding and investigate the bit error rate and the PAPR performance for SCFDMA using ZF and MMSE THP.