Turbo decoding for a new DVD recording system

The modulation code used in a digital versatile disc (DVD) recording system is referred to as the EFMPlus code with a rate of 8/16. We present a new time-varying maximum transition run (TMTR) code for DVD recording systems, which has a rate 8/11 higher than the EFMPlus code and a lower power spectral density (PSD) at low frequencies. Computer simulations indicate that the proposed TMTR code outperforms the EFMPlus code when applied to a partial response optical recording channel. The turbo (iterative) decoding for the TMTR-coded partial response optical recording channel is also investigated, in which the TMTR-coded partial response channel is viewed as the inner code and two parallel concatenated convolutional codes (PCCC's) as the outer code. The error performance of the proposed coding scheme is investigated and compared with the conventional coding scheme, in which both the TMTR code and partial response channel are decoded or detected independently. Simulation results reveal that a coding gain of more than 3 dB can be achieved over the conventional coding scheme.