TPC & LDPC coding for Partial Response channels:

Concatenated codes and iterative decoding is being seriously considered for future digital data storage systems. Partial response channels are a popular channel model for data storage systems. Some of the typical channel coefficients include PR4/EPR4/EEPR4/MEEPR4 for magnetic recording and PR1/PR2 for mageneto optical (MO) recording.

• Although single parity check turbo product codes (TPC/SPC) are inferior comparable to LDPC codes on intersymbol interference (ISI) channels due to the interleaving gain. Further, investigation on the burstiness of errors suggest TPC/SPC may be more compatible with outer Reed Solomon error correction codes (RS-ECC). (paper1, (paper2, paper3).
• Turbo equlizer for intersymbol interference (ISI) channels. (Here is the MAP decoder (non-binary BCJR written in C) for equalizing ISI channels.)

Lorentzian Channels:

We use a more realistic lorentzian channel model to investigate the performance of error correction coding for data storage systems.

• The BER performance and error statistics of TPC/SPC codes on lorentzian channels is investigated. Several trade-offs are investigated: coding gain vs code rate, code rate vs normalized areal density, normalized areal density vs PR targets (paper).

Thresholds for InterSymbol Interference Channels:

We extend density evolution (DE) to compute the thresholds for ISI channels:

• Thresholds of LDPC, turbo and TPC/SPC codes on partial response (PR) channels using density evolution with Gaussian approximation (GA) (paper).