Error rate performance of turbo coding for E2PR4 channel

Turbo coding is widely known as one of effective error control coding techniques in various digital communication systems since this coding method has proposed by C. Berrou, etc in 1993. In digital magnetic recording, it has been cleared that the error correcting capability of turbo coding is superior to most of conventional recording codes as a matter of course. But, the performance of a partial response maximum-likelihood (PRML) system combined with any recording code is degraded by many undesirable factors or effects. To improve the performance of the PRML system in high areal density recording, it is useful to adopt a higher order PRML system or high rate code in a general case. In this paper, the rate 32/34 turbo code combined with an enhanced extended class-4 partial response (E(2)PR4) is proposed. We call this trellis coded partial response (TCPR) system the rate 32/34 turbo-coded E(2)PR4 (32/34 TC-E(2)PR4). Our proposed TCPR system can be expected to get large coding gain and improve the performance of PRML system. As a result, the proposed coding system provides a good performance compared with the conventional systems. In especial, our system can achieve a BER of 10(-5) with SNR of approximately 1.5 dB less than the conventional 8/9 maximum transition run (MTR) coded E(2)PR4ML system at a normalized linear density of 3.