Robust Turbo Equalizer Schemes Against SNR Mismatch

We present a robust algorithm to SNR mismatch for turbo equalizer, which is called the scaled Max-Log-MAP (SMLM) algorithm. For low and moderate loss channel, its performance is very close to that of Log-Map (LM) with exact SNR, while a gap still exists for high loss channel. So we further present a switching scheme between SMLM and LM for high loss channels using the SNR of soft output extrinsic information, which not only obtains good performance close to that of LM with ideal knowledge of SNR, but insensitive to SNR mismatch.