Dissertation
Equalization and coding for the two-dimensional intersymbol interference channel
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2007
DOI:
https://doi.org/10.7273/000005749
Abstract
This dissertation addresses the problems of detection and error correction for binary data corrupted by two-dimensional (2D) intersymbol interference (ISI) and additive white Gaussian noise (AWGN). The 2D-ISI channel occurs in proposed next-generation optical disk systems and holographic storage systems, which store data in 2D pages, and are subject to 2D-ISI at high data densities. This dissertation presents a novel iterative row-column soft decision feedback algorithm (IRCSDFA) which exchanges weighted soft information between row and column maximum-a-posteriori (MAP) detectors. Each MAP detector exploits soft-decision feedback from previously processed rows or columns. The new algorithm gains about 0.3 dB over the previously best published results for the 2 2 averaging mask. For a non-separable 3 3 mask, the IRCSDFA gains 0.8 dB over a previous soft-input/soft-output iterative algorithm which decomposes the 2D convolution into 1D row and column operations. This dissertation also shows how to adapt the IRCSDFA for non-equiprobable binary sources. And this dissertation proposes an approach to optimize the iteration schedule inside the IRCSDFA by using EXIT charts. This dissertation addresses the error floor problem of low-density parity check (LDPC) codes on the binary-input AWGN channel, by constructing a serially concatenated code consisting of two systematic irregular repeat-accumulate (IRA) component codes connected by an interleaver. The interleaver is designed to prevent stopping-set error events in one of the IRA codes from propagating into those of the other code. Simulations with two 128-bit rate 0.707 IRA component codes show that the proposed architecture achieves a much lower error floor at higher SNRs, compared to a 16384-bit rate 1/2 IRA code, but incurs an SNR penalty of about 2 dB at low to medium SNRs. Experiments indicate that the SNR penalty can be reduced at larger blocklengths. This dissertation also demonstrates an iterative joint detection/decoding scheme for the 2D ISI channel by employing IRCSDFA and LDPC codes. Simulation results show that about 1/3 of the gain achieved by IRCSDFA over the previous best equalization algorithm is retained when the two equalizers are combined with LDPC codes.
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Details
- Title
- Equalization and coding for the two-dimensional intersymbol interference channel
- Creators
- Taikun Cheng
- Contributors
- Benjamin Joseph Belzer (Chair)Thomas Robert Fischer (Committee Member) - Washington State University, School of Electrical Engineering and Computer ScienceKrishnamoorthy Sivakumar (Committee Member) - Washington State University, Voiland College of Engineering and Architecture
- Awarding Institution
- Washington State University
- Academic Unit
- School of Electrical Engineering and Computer Science
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 91
- Identifiers
- 99901054940601842
- Language
- English
- Resource Type
- Dissertation