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UBC Theses and Dissertations
Low-complexity iterative decoding for bit-interleaved coded modulation Liu, Jeff Tai-Lin
Abstract
In this thesis, bandwidth-efficient transmission with bit-interleaved coded modulation (BICM) over fading channels is considered. The main focus of this work is on the design and analysis of iterative decoding schemes employing hard-decision feedback. Although suboptimum by nature, hard-decision feedback allows for low-complexity iterative decoders, which renders this approach advantageous for practical implementations. Two particular 16-ary modulation schemes with their corresponding decoders are considered for bandwidth-efficient transmission. The first scheme is 16-ary quadrature amplitude modulation (16QAM) with coherent iterative decoding (ID), so-called BICM-ID, which relies on (possibly imperfect) channel estimation. We analyze the reliability of the output of the demodulator, which is the inner component decoder in the iterative decoding scheme, and we propose the application of a metric truncation technique to improve the quality of the decision variable and thus the performance of hard-decision feedback iterative decoding. Simulation results for different variants of this metric truncation show notable gains in power efficiency, while decoding complexity is not increased. The second scheme we consider is so-called twisted absolute amplitude and differential phase-shift keying (TADPSK), which allows for iterative decoding without the need for channel estimation. We extend previous work on iterative decision-feedback decoding for TADPSK, so-called iterative decision-feedback differential demodulation (DFDM), and propose a sliding-window DFDM (SWDFDM) module as inner component decoder. Similar to the case of 16QAM, the application of metric truncation yields significant performance improvements also for TADPSK transmission. Finally, we compare 16QAM and TADPSK transmission by means of simulations. Depending on the quality of channel estimation, TADPSK with low-complexity iterative DFDM is shown to outperform 16QAM BICM-ID in some cases.
Item Metadata
Title |
Low-complexity iterative decoding for bit-interleaved coded modulation
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2005
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Description |
In this thesis, bandwidth-efficient transmission with bit-interleaved coded modulation
(BICM) over fading channels is considered. The main focus of this work is on the design
and analysis of iterative decoding schemes employing hard-decision feedback. Although
suboptimum by nature, hard-decision feedback allows for low-complexity iterative
decoders, which renders this approach advantageous for practical implementations. Two
particular 16-ary modulation schemes with their corresponding decoders are considered
for bandwidth-efficient transmission. The first scheme is 16-ary quadrature amplitude
modulation (16QAM) with coherent iterative decoding (ID), so-called BICM-ID, which
relies on (possibly imperfect) channel estimation. We analyze the reliability of the output
of the demodulator, which is the inner component decoder in the iterative decoding
scheme, and we propose the application of a metric truncation technique to improve the
quality of the decision variable and thus the performance of hard-decision feedback
iterative decoding. Simulation results for different variants of this metric truncation show
notable gains in power efficiency, while decoding complexity is not increased. The
second scheme we consider is so-called twisted absolute amplitude and differential
phase-shift keying (TADPSK), which allows for iterative decoding without the need for
channel estimation. We extend previous work on iterative decision-feedback decoding
for TADPSK, so-called iterative decision-feedback differential demodulation (DFDM),
and propose a sliding-window DFDM (SWDFDM) module as inner component decoder.
Similar to the case of 16QAM, the application of metric truncation yields significant
performance improvements also for TADPSK transmission. Finally, we compare
16QAM and TADPSK transmission by means of simulations. Depending on the quality
of channel estimation, TADPSK with low-complexity iterative DFDM is shown to
outperform 16QAM BICM-ID in some cases.
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Genre | |
Type | |
Language |
eng
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Date Available |
2009-12-11
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0064862
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2005-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.