RECEIVER OPTIMIZATION FOR DISPERSIVE CHANNELS EMPLOYING CODED MODULATION,WITH APPLICATION IN HIGH RATE DIGITAL SUBSCRIBER LINE TRANSMISSION

摘要

We consider decision-feedback sequence estimation (DFSE) of codedmodulated signals transmitted over dispersive channels and examine its application in high bit rate (＞ 144 kb/s) transmission over metallic subscriber lines. To mitigate the adverse effect of colored noise, we consider a scheme called noise prediction. Formulae for optimal receiver filters under a minimum mean-squared error criterion are derived. It turns out that a key step in the optimization process is the solution of a max-min problem. Because of the complexity in solving this problem, we consider a suboptimal solution which leads to a convenient lower bound on the potential transmission performance. The derived theory is applied to a few example subscriber lines. The numerical results show that DFSE has the potential of offering substantial SNR gain over pure decision-feedback equalization.