The viterbi algorithm has been successfully applied to different pattern recognition and communication tasks. However, if some observations are corrupted by unknown impulsives noise which are not accounted for by the ...
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The viterbi algorithm has been successfully applied to different pattern recognition and communication tasks. However, if some observations are corrupted by unknown impulsives noise which are not accounted for by the distortion measures, recognition performance can degrade significantly. In this paper, we propose a robust viterbi algorithm to handle short impulsive noises with unknown characteristics by means of joint decoding and detection during the viterbi search. To make the algorithm applicable to different noisy conditions with varying amounts of impulsive noise, we further proposed an approach to efficiently estimate the number of corruptions. -We demonstrate the effectiveness of the proposed robust algorithms using spoken digit recognition experiments under two different impulsive noise environments. Under random Gaussian replacement noise, the proposed algorithm reduced digit error by more than 65%. Under the GSM network environment in which lost frames are replaced by interpolated neighboring frames, the robust algorithm reduced digit error by 20%. Furthermore, the proposed algorithm does not degrade performance when impulsive noise is not present.
The authors propose an efficient method of implementing the viterbi algorithm at Nyquist-rate, for linearly modulated signals corrupted by ISI and AWGN. When signalling is M-ary and ISI extends over L - 1 symbols, thi...
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The authors propose an efficient method of implementing the viterbi algorithm at Nyquist-rate, for linearly modulated signals corrupted by ISI and AWGN. When signalling is M-ary and ISI extends over L - 1 symbols, this scheme results in M + CL (complex multiplications, C is the number of samples per symbol), whereas the whitened-matched-filter based viterbi algorithm requires M-L complex multiplications.
Joint decoding of multiple speech patterns so as to improve speech recognition performance is important, especially in the presence of noise. In this paper, we propose a Multi-Pattern viterbi algorithm (MPVA) to joint...
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Joint decoding of multiple speech patterns so as to improve speech recognition performance is important, especially in the presence of noise. In this paper, we propose a Multi-Pattern viterbi algorithm (MPVA) to jointly decode and recognize multiple speech patterns for automatic speech recognition (ASR). The MPVA is a generalization of the viterbi algorithm to jointly decode multiple patterns given a Hidden Markov Model (HMM). Unlike the previously proposed two stage Constrained Multi-Pattern viterbi algorithm (CMPVA), the MPVA is a single stage algorithm. MPVA has the advantage that it cart be extended to connected word recognition (CWR) and continuous speech recognition (CSR) problems. MPVA is shown to provide better speech recognition performance than the earlier techniques: using only two repetitions of noisy speech patterns (-5 dB SNR, 10% burst noise), the word error rate using MPVA decreased by 28.5%, when compared to using individual decoding. (C) 2010 Elsevier B.V. All rights reserved.
Under the background of the rapid development of the Internet, the development information and social status that affect economic regeneration exist in the form of literal data in massive data information. The use of ...
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Under the background of the rapid development of the Internet, the development information and social status that affect economic regeneration exist in the form of literal data in massive data information. The use of viterbi algorithm can establish a digital model of information extraction, so as to quickly and accurately find the important content information in the Internet that influences the development of reform and economic rejuvenation. Therefore, based on the viterbi algorithm, the use of mathematical models to help Jilin economic mechanism research from qualitative to quantitative, and continuously improve the scientific level of economic research. After deep analysis of the implementation principle and algorithm flow of viterbi algorithm, and from the need of text information extraction, an optimization and update scheme is proposed to improve the effectiveness of the algorithm and the accuracy is calculated effectively based on the word feature detection. After simulation experiments show that viterbi algorithm has a good application value in the field of Jilin economic reform research.
The paper deals with the differentially coherent reception of two families of constant-envelope signals: the linear offset quaternary phase shift keying and the binary partial response continuous phase modulation with...
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The paper deals with the differentially coherent reception of two families of constant-envelope signals: the linear offset quaternary phase shift keying and the binary partial response continuous phase modulation with index 0.5. When the conventional (PSK-type) differentially coherent detector is used, a large performance degradation, compared with that of coherent receiver, is observed. The reason for this is the presence of an inherent intersymbol interference (ISI) in the signal and also noise enhancement and correlation introduced by the receiver filter. We present here a differential detection strategy which compensates for ISI and avoids noise enhancement. We start by deriving a phase estimate, which takes into account the presence of the inherent ISI. This phase estimate is then used in the decision metric of a coherent receiver. The resulting decision rule can be implemented using the viterbi algorithm. Simple viterbi receivers with good performance are obtained. Simulation results are given.
In the previous paper, we established the theoretical foundations of a new class of area-efficient architectures for the viterbi algorithm. In this paper, we will show area-efficient architectures for practical codes ...
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In the previous paper, we established the theoretical foundations of a new class of area-efficient architectures for the viterbi algorithm. In this paper, we will show area-efficient architectures for practical codes to illustrate the design procedures and demonstrate the favorable area-time tradeoff results. Three examples from convolutional codes, matched-spectral-null (MSN) trellis codes, and Ungerboeck codes will be presented. We will also discuss the application of our area-efficient techniques to codes with a very large numbers of states, codes with time-varying trellises, and a programmable viterbi decoder.
In this article, a precise phase-based radar distance measurement system using a viterbi decoder to resolve phase ambiguity is presented. Relying on the frequency-modulated continuous-wave radar principle, the introdu...
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In this article, a precise phase-based radar distance measurement system using a viterbi decoder to resolve phase ambiguity is presented. Relying on the frequency-modulated continuous-wave radar principle, the introduced method evaluates both the frequency and the phase of the intermediate frequency signal, thus achieving absolute distance measurement with high accuracy. To avoid ambiguity in the distance estimates by half the wavelength of the radio frequency signal, which commonly arises due to 2 pi ambiguity in the measurement of the phase, the proposed viterbi-based method estimates the most likely sequence of distances between the radar front end and the target. To verify the system concept, measurements using a commercial 77 GHz radar module were carried out, whereby the contour of a predefined surface containing steps in the height profile had to be determined. The experimental results confirm that the viterbi-based approach is suitable to resolve phase ambiguity since accurate and repeatable distance estimates were obtained.
This paper presents a novel modified viterbi algorithm to identify the optimal distribution system restoration plan for improving the grid resiliency. In the proposed algorithm, the switching operations performed for ...
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This paper presents a novel modified viterbi algorithm to identify the optimal distribution system restoration plan for improving the grid resiliency. In the proposed algorithm, the switching operations performed for system restoration are the states with the minimum bus voltage being seen as the cost metric for each state and the extent of load recovery as the observed event. When full load recovery is spotted, the dynamic programming algorithm stops, thereby giving the least number of switching pairs necessary for system restoration. Moreover, an improved flexible switching pair operation is employed to maintain the radial nature of distribution system. Several case studies are presented for verifying the performance of the proposed strategy. Multi-fault conditions are considered in testing the system restoration scheme on 33-bus and 69-bus distribution systems. Furthermore, the effects of integrating distributed energy resources and microgrid systems are analyzed.
In this paper, the theory of viterbi algorithm is introduced based on convolutional coding. The application of viterbi algorithm in the Continuous-Phase Frequency Shift Keying (CPFSK) is presented. Analysis for the pe...
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This paper describes how Andrew J. viterbi developed a non-sequential decoding algorithm which proved useful in showing the superiority of convolutional codes over block codes for a given degree of decoding complexity...
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This paper describes how Andrew J. viterbi developed a non-sequential decoding algorithm which proved useful in showing the superiority of convolutional codes over block codes for a given degree of decoding complexity. The viterbi algorithm is now used in most digital cellular phones and digital satellite receivers as well as in such diverse fields as magnetic recoding, voice recognition, and DNA sequence analysis.
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