| Summary: | 碩士 === 國立清華大學 === 電機工程學系 === 99 === As part of the tradeoff between error performance, decoding complexity
and the overhead of rateless codes, the combination of incremental decoding
(ID) and informed dynamic scheduling (IDS), known as IDIDS, is an attractive
solution in binary symmetric channel (BSC). However, applying IDIDS
in an AWGN channel may cause a degradation in BER performance. The
incrementally received symbols from the AWGN channel may not be immediately
utilized in the decoding process directed by IDS, which violates the
basic idea of rateless codes. On the other hand, a stopping criterion combined
with IDS may cause the current decoding attempt to terminate too early, and
the channel information contained in the originally received codeword will
not be used efficiently. In this paper, a new dynamic decoding schedule strategy
is proposed. In the proposed decoder, the new received symbols can be
immediately utilized in the decoding process. For Luby transform (LT) codes
and Raptor codes over an AWGN channel, the proposed algorithm provides
a more balanced tradeoff. In the case of Raptor codes, the BER performance
is obviously improved.
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