CFO mitigation using adaptive frequency-domain decision feedback equalization for uplink SC-FDMA

To mitigate Inter-Carrier Interference (ICI) due to large Carrier Frequency Offset (CFO) in an uplink Single- Carrier Frequency Division Multiple Access system, a 3-tap Adaptive Frequency Domain Decision Feedback Equalizer (AFD- DFE) is designed in this work by exploiting the banded and sparse structure of the equivalent channel matrix. The block Recursive Least Squares (RLS) algorithm is used for adaptation and both the feedforward and feedback filters are implemented in the frequency-domain. Consequently, the complexity of the block RLS, by exploiting the matrix structure in the frequency-domain, is reduced substantially when compared to its time-domain counterpart. Ultimately, it will be shown that the proposed AFD- DFE exhibits significant excellent performance improvement when compared to a 1-tap AFD-DFE while still enjoying a low computational complexity.