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Viterbi sequence detectors and Turbo decoders are widely used in the receivers of mobile communications systems. They are offer an efficient means of implementing a near-maximum likelihood receiver. However, Viterbi sequence estimators are usually based on the assumption of Gaussian noise and/or interference statistics. It is becoming clear that for third generation and enhanced second generation...
The design of optimal nonlinear filters for signal processing has involved mostly nonparametric estimation. This paper discusses the elements of parametric design for analog signal processing. It provides details for the class of conjunctive homothetic granulometric bandpass filters. These are nonlinear and their optimization in the signal-union-noise model for random sets can be completely characterized...
The goal of this paper is to present a new approach of stationary cost function adaptation algorithm. First the derivation of the algorithm is considered, then computer simulation results are provided.
This paper presents proposed walking distance measurement method for hand-help GPS receivers. The method is based purely on GPS receiver output. The following requirements can be set for hand held GPS receiver distance measurement: • The operation of the distance measurement must be autonomous. • The distance measurement must work under any condition, where the receiver is operable • The distance...
The contribution of this work is the derivation of the joint maximum likelihood estimator (MLE) of complex amplitude and Doppler frequency of a radar/sonar target signal embedded in correlated non-Gaussian noise modeled as a compound-Gaussian process. The estimation accuracy of the ML frequency estimator is investigated and compared with that of the well-known periodogram and ESPRIT estimators under...
We discuss an important attribute of a discrete wavelet transform derived using a group-theoretic approach. We use discrete affine group AFF(GF(p)) of the Galois field GF(p) for generating wavelet atoms. We develop a common method of computing the wavelet distribution based on the fast Fourier-Weyl transform.
We derive a watermark detector for images which are watermarked in a multiplicative way. Under the assumptions that the watermark coefficients are a known, binary valued sequence and that the original image coefficients are an i.i.d. random sequence from a Weibull distribution, we show that this watermark should be detected by raising the observations to the power β before correlating them with the...
This paper deals with a cancellation multiuser detector for CDMA communication systems. Proposed receiver is supposed to be used at the end of up-link channel, leading to consider multipath fading phenomena. Proposed receiver approach consists in performing a weighted selective cancellation of the co-channel interfering signals, divided in two different groups according to the received power level:...
In 1996, a new spread spectrum communication system, called Frequency Diversity Spread Spectrum (FDSS), was proposed as a system to mitigate the problems of the common spread spectrum techniques. In this paper, two blind self-reference optimum beamforming methods tailored for the FDSS signalling scheme using the trivial repetition code are derived based on the inherent cross-correlation properties...
The paper defines the conditions for the coefficients of a linear color transformation that guarantee that after one cycle of transformation and inverse transformation all further cycles of transformation do not introduce rounding errors to sample values. Moreover, the upper limits of the rounding error can be calculated according to the formulas given in the paper. The results are very important...
In this paper, we propose an iterative scheme for joint tracking of fading channels and demodulation of multiuser CDMA signals operating asynchronously over multipath fading channels. We use the expectation maximization algorithm to track the time-varying channel and as a by-product we also achieve estimates of the input signals. We show that the maximum a posteriori estimates of the fading channels...
We propose an original VLSI architecture to be implemented on a single chip focal plane array, dedicated to the detection and the tracking of cooperative active targets in unfriendly and noisy environment. The system we describe can detect IR targets very fast (in less than 1 ms) at signal-to-noise ratios close or below 0 dB. The basic principle is an asynchronous detection of pseudo-random IR target...
Through the present paper the use of Negative Beamforming for Speech Enhancement is explored. This method may be used to eliminate or enhance a specific signal using a binaural array, and its extension to three-microphone arrays is also shown. The fundamentals of the technique are reviewed, and a structure to control and improve its angular selectivity is presented. Results obtained in a real situation...
We consider symbol rate estimation of an unknown signal linearly modulated by a sequence of symbols. We rely on the received signal is cyclostationarity, and consider an existing estimator obtained by maximizing in the cyclic domain a (possibly weighted) sum of modulus squares of cyclic correlation estimates. Although widely used, this estimate seems not to have been studied rigorously when the number...
The design and implementation of a real-time general-purpose auralization device is presented in this paper. The goal has been to make a stand-alone device that can also be controlled from a PC. Several auralization and spatialization methods are included, such as binaural headphone and loudspeaker auralization, and vector base amplitude panning for multi-channel loudspeaker sound reproduction. Combining...
This paper presents the work done to improve the recognition rate in an isolated word recognition problem with single utterance training. The negative effect of errors (due to insufficient training data) in estimated model parameters is compensated by fusing the information obtained from HMM evaluation and those generated for the word length and voicing at the beginning and end of the word. A Bayesian...
This paper presents a novel design scheme, involving response sharpening process, for generating two-dimensional diamond/quadrant perfect-reconstruction (PR) linear-phase FIR filter banks with considerably reduced arithmetic operations, narrow transition bandwidth and good frequency selectivity. The scheme uses short 2-D Nyquist(M) subfilters, preferably multiplier-free ones, as basic building elements...
In this paper is proposed a method to characterize a Time-Frequency Representation (TFR). This characterization takes place in a process which aim is to extract spectral patterns of an uni-dimensional signal from its TFR. The originality of this method is that the Time-Frequency plane is considered from a local point of view. Statistical features of set of TFR coefficients are defined in order to...
This paper proposes the use of a polynomial interpolator structure (the Farrow structure) which is efficiently realizable in hardware, for high-quality geometric transformation of 2-D and 3-D images. Polynomial based interpolators such as B-splines are exactly implementable in the Farrow structure framework. Using this structure, the advantage in computational complexity is demonstrated to be very...
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