Which one is more sensitive to carrier frequency offsets - OFDMA or SC-FDMA?

Single carrier frequency division multiple access (SC-FDMA) has been adopted for multi-user systems due to its low peak to average power ratio and improved bit error rate performance as compared to orthogonal frequency division multiple access (OFDMA) with minimum mean square error (MMSE) equalization. In this paper, we investigate the robustness of these two technologies in the presence of carrier frequency offsets (CFOs) for uplink transmissions. We present a generalized system model for SC-FDMA and OFDMA uplink transmissions and compare the bit error rate performance of different sub-carrier allocation and CFO compensation schemes. We show that surprisingly, SC-FDMA is more sensitive to CFOs as compared to OFDMA, so the performance gains offered by SC-FDMA with MMSE equalization are lost in the presence of CFOs. On the other hand, the performance degradation due to CFO is relatively small for SC-FDMA with zero forcing equalization. We also show that the performance of grouped allocation and interleaved allocation becomes similar in the presence of CFOs as opposed to the perfect synchronization scenario.