Improved Turbo Equalization Schemes Robust to SNR Estimation Errors

摘要

An improved Max-Log-Map (MLM) turbo equalization algorithm called Scaled Max-Log-Map (SMLM) iterative equalization is presented. Simulations show that the scheme can dramatically outperform the MLM besides it is insensitive to SNR mismatch. Unfortunately, its performance is still much worse than that of Log-Map (LM) with exact SNR over high-loss channels. Accordingly, we also propose a new SNR estimation algorithm based on the reliability values of soft output extrinsic information of SMLM decoder. Using the new scheme, we obtain good performance close to that of LM with ideal knowledge of SNR.