A SNR Estimation Method in Turbo Detection System
迭代均衡系统中的一种SNR估计方法

In this paper, the sensitivity of MAP algorithm and its reduced ones as Max-Log-MAP and Scaled Max-Log-Map to SNR mismatch in turbo detection systems are analyzed. Due to the fact of insensitivity of Scaled Max-Log-MAP algorithm to SNR mismatch, a new SNR estimation method is proposed using the soft output extrinsic information. Then, a new turbo equalization scheme is also provided utilizing the SNR estimation algorithm, and the corresponding performance of new equalization algorithm is also studied. The simulation results show that new equalization scheme with reliability-based SNR estimation method performs very close to MAP algorithm with known SNR, although it does not need pilot symbols.