EXIT-Chart-Based LDPC Code Design for 2D ISI Channels

Kong, Lingjun; Guan, Yong Liang; Zheng, Jianping; Han, Guangjie; Cai, Kui; Chan, Kheong-Sann

doi:10.1109/tmag.2013.2248351

Cited by 29 publications

(31 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main challenge is that the overwrite effect in the TDMR channel model causes the LLR PDFs at the VND's input and output to be non-Gaussian. Thus, we cannot rely on a Gaussian assumption (as does, e.g., [7]) to find the EXIT chart curves.…”

Section: Exit Chart Based Ira Code Design For Tdmr Channel With mentioning

confidence: 99%

“…Since the 2D-ISI equalizer output LLR PDF is well modeled as a two-component GMM (as can be seen in Fig. 3), we cannot compute the VND output mutual information I E,V N D using the general closed form equation used in [7], which relies on a Gaussian assumption. To find I E,V N D , we numerically calculate the output mutual information of the VND through the IRA decoder iterations.…”

Section: Exit Chart Based Ira Code Design For Tdmr Channel With mentioning

confidence: 99%

“…In [7], the authors consider a TDMR channel model with 2D-ISI, and optimize the LDPC code to take into account the statistics of the LLRs output from a 2D-ISI detector. But [7] does not consider the TDMR overwrite effect which occurs at high coded bit densities (i.e., lower values of GPB).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

EXIT chart based IRA code design for TDMR

Mehrnoush

Belzer

Sivakumar

et al. 2016

2016 Annual Conference on Information Science and Systems (CISS)

View full text Add to dashboard Cite

This paper presents an extrinsic information transfer (EXIT) chart based irregular repeat-accumulate (IRA) code design technique for a two-dimensional magnetic recording (TDMR) turbo-equalizer that employs a Voronoi magnetic grain model. The channel model also includes two-dimensional intersymbol interference (2D-ISI) and additive white Gaussian noise (AWGN). At high bit densities (e.g., between 1 and 3 magnetic grains per coded bit (GPB)), occasionally a bit will not be written on any grain, and hence will effectively be "overwritten" (or erased) by bits on surrounding grains. The proposed code design takes into account the statistics of the TDMR channel to decrease overwrite effects. The proposed receiver uses a 2D-ISI BCJR equalizer and IRA decoder in a turbo-equalization approach. To design the IRA code, we find the experimental EXIT chart curves of the check node decoder (CND) and the combination of the variable node decoder (VND) with the 2D-ISI equalizer. We fit the VND and CND EXIT chart curves to find the IRA code's optimized variable node degree distribution for the TDMR channel. Simulation results show that the IRA codes optimized for the TDMR Voronoi grain model achieve up to a 3.3% density increase in user-bits/grain (U/G) compared to IRA codes designed for AWGN channels. At 1.2 GPB, the designed IRA codes achieve densities as high as 0.455 U/G, corresponding to an areal density of about 4.6 Terabits/in 2 on typical magnetic hard disks with 10 Teragrains/in 2 ; this is nearly a factor of 5 better than the best commercially available systems.

show abstract

Section: Exit Chart Based Ira Code Design For Tdmr Channel With mentioning

confidence: 99%

Section: Exit Chart Based Ira Code Design For Tdmr Channel With mentioning

confidence: 99%

See 1 more Smart Citation

EXIT chart based IRA code design for TDMR

Mehrnoush

Belzer

Sivakumar

et al. 2016

2016 Annual Conference on Information Science and Systems (CISS)

View full text Add to dashboard Cite

show abstract

“…The design problem of matching the CND curve and the combined DET and VND curve is equivalent to solving the following linear programming problem [13] …”

Section: Optimized Degree Distributionsmentioning

confidence: 99%

EXIT-chart-based LDPC code design for spatial modulation

Liu

Zheng

Dou

et al. 2014

2014 4th IEEE International Conference on Information Science and Technology

Self Cite

View full text Add to dashboard Cite

The low-density parity-check (LDPC) code optimization for spatial modulation (SM) is studied using the extrinsic information transfer (EXIT) chart technique. First, for the maximum a posteriori probability (MAP) detector of the SM, its EXIT chart is characterized through Monte Carlo simulations. Then, the optimized degree distribution is acquired by matching the check node decoder curve to the combined detector and variable node decoder curve. Simulation results show that these optimized codes have performance gains from 0.3 to 1.3dB, compared with the regular code and the optimized code for the additive Gaussian white noise channel, in 4×4 and 16×16 multiple-antenna systems.

show abstract

“…In our previous work [12]- [13], new LDPC codes optimized for 2D ISI channels detected using symbol-based BCJR 2D detector (2D-DET) have been designed based on Extrinsic Information Transfer (EXIT) curve fitting of modified EXIT charts, which can achieve better performance than codes optimized for AWGN channels. However, the computational complexity of the BCJR 2D-DET is prohibitive, hence iterative row-column soft decision feedback algorithm (IRCSDFA) was proposed in [16] as a reduced-complexity 2D-DET.…”

Section: Introductionmentioning

confidence: 99%

EXIT-chart-based threshold calculation of LDPC code in 2D ISI channels

Kong

Guan

Han

et al. 2013

2013 19th Asia-Pacific Conference on Communications (APCC)

Self Cite

View full text Add to dashboard Cite

An algorithm based on the fitting of modified Extrinsic Information Transfer (EXIT) chart is proposed to calculate the thresholds of low-density parity-check (LDPC) codes optimized for the two-dimensional (2D) intersymbol interference (ISI) channels encountered in high-density magnetic recording, such as bit-patterned magnetic recording (BPMR) and two-dimensional magnetic recording (TDMR). The modified EXIT chart algorithm determines the LDPC threshold by fitting the EXIT curve of the variable node decoder (VND) combined with 2D detector (2D-DET) to the EXIT curve of the check node decoder (CND). Both the optimal Bahl-Cocke-Jelinek-Raviv (BCJR) 2D-DET and reduced-complexity Gaussian-approximated iterative rowcolumn 2D-DET are considered.

show abstract

EXIT-Chart-Based LDPC Code Design for 2D ISI Channels

Cited by 29 publications

References 24 publications

EXIT chart based IRA code design for TDMR

EXIT chart based IRA code design for TDMR

EXIT-chart-based LDPC code design for spatial modulation

EXIT-chart-based threshold calculation of LDPC code in 2D ISI channels

Contact Info

Product

Resources

About