Sparsity based adaptive thresholding for DFE in SC-FDMA

For single-carrier systems with frequency domain equalization, such as SC-FDMA, decision feedback equalization (DFE) performs better than linear equalization and has much lower computational complexity than sequence maximum likelihood detection. The main challenge in DFE is the feedback symbol selection rule. In this paper, we give a theoretical framework for a simple, sparsity based thresholding algorithm. We feed back multiple symbols in each iteration, so the algorithm converges fast and has a low computational cost. We show how the initial solution can be obtained via convex relaxation instead of linear equalization. Numerical results illustrate significant performance improvement in terms of bit error rate compared to the MMSE solution.