Automatic equalizer including a decoder of error‐correcting code and its development
Ryuji Kohno, Hideki Imai, Mitsutoshi Hatori · Electronics and Communications in Japan (Part I Communications) · 1985
Abstract This paper proposes an automatic equalizer containing a decoder for an error‐correcting code. The purpose is the comprehensive compensation of code errors caused by intersymbol interference due to band‐limitation and code errors caused by channel variation and noise. These are major problems in realizing a highly reliable communication. The system is called AEDEC and can reduce the correction error in the tap coefficient innovation due to decision error and the error propagation in a decision‐feedback scheme. Consequently, it can achieve a stable convergence in the channel in an adverse condition where a traditional automatic equalizer cannot lead to a convergence. A control method is proposed for innovation of a tap coefficient and data feedback before the feedback decision based on the decoding reliability. This is estimated in the decoding process of the error‐correcting code leading to the optimum control, and minimizing the effects of undetection or miscorrection of the decoding errors. Furthermore, as an extension of AEDEC, an adaptive canceller is proposed which eliminates the intersymbol interference without emphasizing noise by utilizing AEDEC as a means of preliminary decision. As a result of computer simulation applying algebraic decoding and analog‐weight minimum decoding to recursive (7, 4) Hamming code, it is shown that the proposed schemes can lead to a stable convergence, thereby drastically improving the bit‐error rate.