Journal ArticleDOI
A Bayesian maximum-likelihood sequence estimation algorithm for a priori unknown channels and symbol timing
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TLDR
It is shown that the optimum demodulator for the case of an a priori unknown channel and symbol timing can be approximated using a modified Viterbi algorithm (VA), in which the branch metrics are obtained from the conditional innovations of a bank of extended Kalman filters (EKFs).Abstract:
It is shown that the optimum demodulator for the case of an a priori unknown channel and symbol timing can be approximated using a modified Viterbi algorithm (VA), in which the branch metrics are obtained from the conditional innovations of a bank of extended Kalman filters (EKFs). Each EKF computes channel and timing estimates conditioned on one of the survivor sequences in the trellis. It is also shown that the minimum-variance channel and timing estimates can be approximated by a sum of conditional EKF estimates, weighted by the VA metrics. Simulated bit error rate (BER) results and averaged-squared channel/timing error trajectories are presented, with estimation errors compared to the Cramer-Rao lower bound. The BER performance of the modified VA is also shown to be superior to that obtained using a decision-directed channel/timing estimation algorithm. >read more
Citations
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Journal ArticleDOI
Multichannel blind identification: from subspace to maximum likelihood methods
Lang Tong,S. Perreau +1 more
TL;DR: A review of blind channel estimation algorithms is presented, from the (second-order) moment-based methods to the maximum likelihood approaches, under both statistical and deterministic signal models.
Journal ArticleDOI
Space-time modems for wireless personal communications
TL;DR: Channel estimation, equalization, and filtering techniques for space-time modems in the forward and reverse links are discussed and a signal model for the wireless environment is developed.
Journal ArticleDOI
MLSE for an unknown channel .I. Optimality considerations
Keith M. Chugg,Andreas Polydoros +1 more
TL;DR: It is shown that a fractionally-spaced whitened matched filter, matched to the known data pulse, provides a set of sufficient statistics when a tapped delay line channel model is assumed, and that the problem is ill-posed when the channel impulse response is generalized to a CT, finite-length model.
Journal ArticleDOI
Adaptive soft-input soft-output algorithms for iterative detection with parametric uncertainty
TL;DR: The exact expressions for the soft metrics in the presence of parametric uncertainty modeled as a Gauss-Markov process are derived in a novel way that enables the decoupling of complexity and observation length.
Patent
Method and device for estimating transmitted signals in a receiver in digital signal transmission operations
TL;DR: In this article, a channel estimation filter is used to adapt the channel estimate and also to generate weight factors, where the coefficients of the prefilter are generated as a function of the estimated channel and the weight factors.
References
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Journal ArticleDOI
Maximum-likelihood sequence estimation of digital sequences in the presence of intersymbol interference
TL;DR: In this paper, a maximum likelihood sequence estimator for a digital pulse-amplitude-modulated sequence in the presence of finite intersymbol interference and white Gaussian noise is developed, which comprises a sampled linear filter, called a whitened matched filter, and a recursive nonlinear processor, called the Viterbi algorithm.
Journal ArticleDOI
Brief paper: Detection and estimation for abruptly changing systems
TL;DR: The problem of state estimation and system structure detection for discrete stochastic dynamical systems with parameters which may switch among a finite set of values is considered and a unified treatment of the existing suboptimal algorithms is provided.
Journal ArticleDOI
Maximum likelihood sequence estimation of CPM signals transmitted over Rayleigh flat-fading channels
J.H. Lodge,M.L. Moher +1 more
TL;DR: A method for the sequential updating of log- likelihood functions for maximum-likelihood sequence estimation is presented and it is shown that, in a general case, this method can be implemented using Kalman filtering techniques.
Journal ArticleDOI
Joint estimation of PN code delay and multipath using the extended Kalman filter
TL;DR: It is shown that the extended Kalman filter (EKF) can be used to obtain joint estimates of time-of-arrival and multipath coefficients for deterministic signals when the channel can be modeled as a tapped-delay line.
Journal ArticleDOI
A digital DS spread-spectrum receiver with joint channel and Doppler shift estimation
TL;DR: The Cramer-Rao lower bound for time-invariant joint channel, delay, and Doppler estimation is derived, and compared with the ensemble averaged mean-squared error of the EKF estimator.