Satellites receiving Automatic Identification System (AIS) packets in dense areas are particularly prone to AIS channel overload due to the extensive number of vessels. Thus a failure of detection might be caused by t...
详细信息
An instance of the viterbi algorithm has been applied to the cubic phase function and chirp-rate estimation. The proposed algorithm has shown excellent performance for high noise environment. The obtained chirp-rate e...
详细信息
An instance of the viterbi algorithm has been applied to the cubic phase function and chirp-rate estimation. The proposed algorithm has shown excellent performance for high noise environment. The obtained chirp-rate estimate is used in the instantaneous frequency estimation. The proposed instantaneous frequency estimator gives superior performance with respect to the state-of-the-art techniques for signals with non-linear instantaneous frequency. (C) 2010 Elsevier B.V. All rights reserved.
作者：
Kavcic, AMoura, JMFHarvard Univ
Div Engn & Appl Sci Cambridge MA 02138 USA MIT
LIDS Cambridge MA 02139 USA MIT
Dept Elect Engn & Comp Sci Cambridge MA 02139 USA
This work designs sequence detectors for channels with intersymbol interference (ISI) and correlated land/or signal-dependent) noise. We describe three major contributions. i) First, by modeling the noise as a finite-...
详细信息
This work designs sequence detectors for channels with intersymbol interference (ISI) and correlated land/or signal-dependent) noise. We describe three major contributions. i) First, by modeling the noise as a finite-order Markov process, we derive the optimal maximum-likelihood sequence detector (MLSD) and the optimal maximum a posteriori (MAP) sequence detector, extending to the correlated noise case the viterbi algorithm, We show that, when the signal-dependent noise is conditionally Gauss-Markov, the branch metrics in the MLSD are computed from the conditional second-order noise statistics. We evaluate the branch metrics using a bank of finite impulse response (FIR) filters. ii) Second, we characterize the error performance of the MLSD and MAP sequence detector. The error analysis of these detectors is complicated by the correlation asymmetry of the channel noise. We derive upper and lower bounds and computationally efficient approximations to these bounds based on the banded structure of the inverses of Gauss-Markov covariance matrices. An experimental study shows the tightness of these bounds. iii) Finally, we derive several classes of suboptimal sequence detectors, and demonstrate how these and others available in the literature relate to the MLSD. We compare their error rate performance and their relative computational complexity, and show how the structure of the MLSD and the performance evaluation guide us in choosing a best compromise between several types of suboptimal sequence detectors.
This paper shows how to apply the viterbi algorithm to detect randomly located impulses which have Gaussian distributed amplitudes. Our detector can deal with cases of severely overlapping wavelets. Experimental resul...
详细信息
This paper shows how to apply the viterbi algorithm to detect randomly located impulses which have Gaussian distributed amplitudes. Our detector can deal with cases of severely overlapping wavelets. Experimental results and comparisons to Kormylo and Mendel's [12] single-most-likely-replacement detector are provided, using synthetic data.
This paper presents a reduced complexity viterbi algorithm for use as sequence estimator for linear intersymbol interference channels with coarsely located coefficients. In particular, the complexity does not depend o...
详细信息
This paper presents a reduced complexity viterbi algorithm for use as sequence estimator for linear intersymbol interference channels with coarsely located coefficients. In particular, the complexity does not depend on the channel impulse response length but only on the number of nonzero coefficients. No approximations are used in the algorithm.
Multi Pattern viterbi algorithm (MPVA) to jointly decode and recognize multiple speech patterns for automatic speech recognition (ASR) is proposed. The MPVA is a generalization of the viterbi algorithm (VA) to jointly...
详细信息
ISBN:
(纸本)9781424445462
Multi Pattern viterbi algorithm (MPVA) to jointly decode and recognize multiple speech patterns for automatic speech recognition (ASR) is proposed. The MPVA is a generalization of the viterbi algorithm (VA) to jointly decode multiple patterns for a given standard Hidden Markov Model (HMM). Unlike our previously proposed Constrained Multi Pattern viterbi algorithm (CMPVA), the MPVA does not require the Multi Pattern Dynamic Time Warping (MPDTW) algorithm. The new algorithm has the advantage that it can be extended to connected word recognition (CWR) and continuous speech recognition (CSR) problems. It also gives an improved speech recognition performance over the earlier techniques. Using only two repetitions of noisy speech patterns (-5 dB SNR, 10% burst noise), the word error rate using the proposed MPVA decreases by 28.5 percent, when compared to using individual decoding.
A low complexity Soft-Input Soft-Output (SISO) module, based on viterbi algorithm, is proposed. This module is suitable for turbo decoding of Parallel Concatenated Convolutional Codes (PCCCs). The interest of this app...
详细信息
A low complexity Soft-Input Soft-Output (SISO) module, based on viterbi algorithm, is proposed. This module is suitable for turbo decoding of Parallel Concatenated Convolutional Codes (PCCCs). The interest of this approach resides on the fact that the viterbi algorithm is used unmodified, still accepting as its inputs soft information. The hard output of the viterbi algorithm is used to compute the extrinsic information based on the knowledge of systematic and a priori information. Also, a set of scaling factors is used to improve the quality of the extrinsic information. The scaling factors are obtained based on a semi-analytical method. The convergence properties and performance of the proposed turbo decoder are evaluated using EXtrinsic Information Transfer (EXIT) charts and Bit Error Rate (BER) simulations.
Distributed denial of service attacks aim at making a given computational resource unavailable to users. A substantial portion of commercial Intrusion Detection Systems operates only with detection techniques based on...
详细信息
ISBN:
(纸本)9781467367707
Distributed denial of service attacks aim at making a given computational resource unavailable to users. A substantial portion of commercial Intrusion Detection Systems operates only with detection techniques based on rules for the recognition of pre-established behavioral patterns (called signatures) that can be used to identify these types of attacks. However, the characteristics of these attacks are adaptable, compromising thus the efficiency of IDS mechanisms. Thus, the goal of this paper is to evaluate the feasibility of using the Hidden Markov Model based on viterbi algorithm to detect distributed denial of service attacks in data communication networks. Two main contributions of this work can be described: the ability to identify anomalous behavior patterns in the data traffic with the viterbi algorithm, as well as, to obtain feasible levels of accuracy in the detection of distributed denial of service attacks.
IoT is a revolutionary technology which empowers physical devices with the ability to communicate and take collaborative decision without human intervention. Among the various protocol standards defined for IoT physic...
详细信息
ISBN:
(纸本)9781509037049
IoT is a revolutionary technology which empowers physical devices with the ability to communicate and take collaborative decision without human intervention. Among the various protocol standards defined for IoT physical layer Bluetooth Low Energy is a promising one owing to its low power consumption. In this paper, a viterbi algorithm based BLE receiver is proposed where a joint viterbi detector and decoder is used rather than using two distinct viterbi processors for detection and decoding. The proposed model is simulated using Scilab and from the simulation results it is evident that the BER requirement of BLE is met at a SNR value of 5dBm. The performance of the viterbi algorithm based BLE receiver is found to be superior to other demodulation schemes used. The performance of BLE receiver using joint viterbi detector and decoder is on par with the receiver model using two viterbi processors.
A new nondata-aided frequency offset estimation method has been proposed for GMSK which is based on viterbi algorithm to remove the information phase of the complex envelope signal. It has. wide frequency offset estim...
详细信息
ISBN:
(纸本)9781424405169
A new nondata-aided frequency offset estimation method has been proposed for GMSK which is based on viterbi algorithm to remove the information phase of the complex envelope signal. It has. wide frequency offset estimation range, and its feedforward structure made itself simple digital implementation. Its complexity would be controlled by the viterbi algorithm parameter. Simulation results have shown the validity of the algorithm in frequency offset estimation. At last, the normalized mean square errors (MSE) performance, of the algorithm has also been proposed in additive while Gaussian noise channel.
暂无评论