Sequence-based Block Decision-Aided Equalizer for Turbo Equalization
Dou Gao-qi①; Gao Jun①; Tao Wei①②; Liu Bing①
①Department of Communication Engineering, Naval University of Engineering, Wuhan 430033, China; ②Naval Equipment Research Institute, Beijing 100161, China
Abstract：A sequenced-based Block Decision-Aided Equalizer (BDAE) for turbo equalization is proposed, which can overcome the deficiency of symbol-by-symbol detection equalizers that the A Posteriori Probability (APP) of each symbol is calculated individually based on a Gaussian distribution assumption of the equalizer output. The proposed equalizer used the full decoder’s information instead of the extrinsic information to improve the reliability of the estimated sequences. Replacing hard decision with soft decision reduces the effects of the error propagation. Meanwhile, combining soft decision with sequence-based detection provides more reliable information for the calculation of the APP. Simulation results show the new proposed equalizer leads to better performance compared to the Linear Minimum Mean Square Error (LMMSE) equalizers and the BDFE with hard feedback without sacrificing the computational complexity.
2009, Vol. 31 
