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Sequential decoding

About: Sequential decoding is a research topic. Over the lifetime, 8667 publications have been published within this topic receiving 204271 citations.


Papers
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Patent
29 Dec 2004
TL;DR: In this paper, a multiple fixed threshold scheme for iteratively decoding a received codeword includes making a comparison with a threshold to generate a reconstructed version of the received codeeword.
Abstract: A method and apparatus are provided for error correction of a communication signal. A multiple fixed threshold scheme for iteratively decoding a received codeword includes making a comparison with a threshold to generate a reconstructed version of the received codeword. The threshold has at least two different values that at used during different iterations. The values of the threshold are fixed having been determined prior to decoding. In an embodiment, the fixed thresholds may be based on values for channel parameters and may be selected by a decoder that receives information regarding the channel parameter from a channel estimation unit monitoring the communication channel. Embodiments include decoding methods and apparatus using a threshold having two of more fixed values during the iterative decoding.

37 citations

Proceedings ArticleDOI
10 Dec 2002
TL;DR: The lazy Viterbi decoder is introduced and it is shown how to make it efficient in practice and the running time of the lazy algorithm is essentially independent of the constraint length.
Abstract: The lazy Viterbi decoder is a maximum-likelihood decoder for block and stream convolutional codes. For many codes of practical interest, under reasonable noise conditions, the lazy decoder is much faster than the original Viterbi decoder. For a code of constraint length 6, the lazy algorithm is about 50% faster than an optimized implementation of the Viterbi decoder whenever SNR>6 dB. Moreover, while the running time of the Viterbi decoder grows exponentially with the constraint length, under reasonable noise conditions, the running time of the lazy algorithm is essentially independent of the constraint length. This paper introduces the lazy Viterbi decoder and shows how to make it efficient in practice.

37 citations

Patent
27 Jan 2009
TL;DR: In this paper, a trellis-exploration algorithm similar to the Viterbi algorithm is proposed to generate spatial subchannel codes for wireless devices operating in a cooperative antenna array using an asymptotically optimal decoding algorithm.
Abstract: Spatial subchannel codes for wireless devices operating in a cooperative antenna array are generated using an asymptotically optimal decoding algorithm, such as a trellis-exploration algorithm similar to the Viterbi algorithm. A trellis may be constructed using a number of desired subchannels, at least one code length, and a number of code-chip parameters. A fitness function is derived from a mathematical relationship between codes, and may include some measure of correlation of the codes. The selected codes correspond to paths having optimal path metrics derived from the fitness function. Multiple iterations through the trellis may be performed to refine a selection of the codes.

37 citations

Journal ArticleDOI
Hisashi Kobayashi1, D. Tang
TL;DR: Analytical and simulation results on the performance of the proposed decoding scheme are presented and an asymptotic expression for the decoding error rate is derived in closed form as a function of the channel signal-to-noise ratio.
Abstract: Decoding of a correlative level coding or partialresponse signaling system is discussed in an algebraic framework. A correction scheme in which the quantizer Output includes ambiguity levels is proposed. The implementation and algorithm of error correction is discussed in some detail. An optimum design of the quantizer based on Chow's earlier work is discussed. Both analytical and simulation results on the performance of the proposed decoding scheme are presented. An asymptotic expression for the decoding error rate is derived in closed form as a function of the channel signal-to-noise ratio. This is also compared with the conventional bit-by-bit detection method and the maximumlikelihood decoding method recently studied.

36 citations

Journal ArticleDOI
TL;DR: A novel decoding method based on the so-called list Viterbi algorithm (LVA), which can significantly reduce the error flag rate relative to conventional VA-based decoding, resulting in dramatically improved decoded audio quality and a number of methods for screening undetected errors in the audio domain.
Abstract: Hybrid in-band on-channel digital audio broadcasting systems deliver digital audio signals in such a way that is backward compatible with existing analog FM transmission. We present a channel error correction and detection system that is well-suited for use with audio source coders, such as the so-called perceptual audio coder (PAC), that have error concealment/mitigation capabilities. Such error mitigation is quite beneficial for high quality audio signals. The proposed system involves an outer cyclic redundancy check (CRC) code that is concatenated with an inner convolutional code. The outer CRC code is used for error detection, providing flags to trigger the error mitigation routines of the audio decoder. The inner convolutional code consists of so-called complementary punctured-pair convolutional codes, which are specifically tailored to combat the unique adjacent channel interference characteristics of the FM band. We introduce a novel decoding method based on the so-called list Viterbi algorithm (LVA). This LVA-based decoding method, which may be viewed as a type of joint or integrated error correction and detection, exploits the concatenated structure of the channel code to provide enhanced decoding performance relative to decoding methods based on the conventional Viterbi algorithm (VA). We also present results of informal listening tests and other simulations on the Gaussian channel. These results include the preferred length of the outer CRC code for 96-kb/s audio coding and demonstrate that LVA-based decoding can significantly reduce the error flag rate relative to conventional VA-based decoding, resulting in dramatically improved decoded audio quality. Finally, we propose a number of methods for screening undetected errors in the audio domain.

36 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202351
2022112
202124
202026
201922
201832