An Improved Receive Diversity Combining Technique for SC-FDMA-Based Cooperative Relays

In this paper, two receive diversity combining techniques are proposed for cooperative relay systems based on single-carrier frequency division multiple access (SC-FDMA) when DFT spreading sizes for a mobile station (MS) and relay station (RS) are different. A simplifled-MRC (S-MRC) technique performs diversity combining in the time-domain by using the estimated channel weights and initial estimates obtained by SC-FDMA signal detector. An interference rejection-MRC (IRMRC) technique performs diversity combining in the frequencydomain by adjusting DFT spreading size at the receiver. It is shown by computer simulation that the proposed receive combining techniques achieve a significant diversity gain over the conventional ones.