Distance-Enhancing Constrained Codes for Optical Recording Channels
Kui Cai, Kees A. Schouhamer Immink, Zhiliang Qin · 2008
This paper proposes distance-enhancing constrained codes for optical recording channels. The repeated minimum transition runlength (RMTR) constraints are first investigated, based on error event analysis and capacity calculation. A new RMTR constrained code is then proposed. Compared with the codes used in standard systems, it imposes the minimum achievable RMTR constraint on the channel bit stream with the least decoding window length, without introducing additional code rate loss. A systematic method is further proposed, which can efficiently combine the RMTR code with the parity-check (PC) codes. Simulation results show that the new RMTR constrained PC code performs 1.1 dB better than the 17PP code, at BER = 10-5and high recording density.