Application of Turbo Codes to High-Density Optical Disc Storage Using 17PP Code

We have previously proposed a novel trellis decoding technique for soft-output decoding of the 17PP code. Using this technique, we have developed a turbo-coded 17PP system, and showed improvement in the bit error rate (BER) in an additive white Gaussian noise (AWGN) channel by simulation. In this paper, we describe an optimized trellis of the 17PP code that has only 15 states and 53 branches. It is well known that a partial response (PR) channel can be regarded as a convo-lutional code with the trellis structure. Therefore we merged the PR1221 trellis into the 17PP trellis, which we call the “PR17PP” trellis, and similarly optimized this trellis. With the soft-in soft-out (SISO) decoders using this “PR17PP” trellis, it is experimentally confirmed that the turbo-coded 17PP system effectively increases the user capacity of an optical disc.