List Viterbi Decoding with Continuous Error Detection for Magnetic Recording

The List Viterbi Algorithm (LVA) with an arithmetic coding based continuous error detection (CED) scheme is applied to high-order partial-response magnetic recording channels. Commonly used magnetic recording systems employ distance-enhancing codes along with parity-check post-processors to correct most dominant error events. The system presented here inserts a CED encoder between the outer RS code and the channel, and utilizes LVA along with CED's early-error-detection capabilities to improve the performance of the Viterbi decoder. Simulations show that this system results in a 2 dB improvement over MTR encoded E²PRML decoding at a BER of 2x10^-6 in E²PR4 equalized additive white Gaussian noise and localizes error occurrences to the end of the sector. It is also shown analytically that the number of bits at the end of the sector in which errors occur with any specified probability remains constant as the sector-size increases.