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Trellis-coded OFDM signal detection with maximal ratio combining and combined equalization and trellis decoding

IEICE TRANSACTIONS ON COMMUNICATIONS 1997年第4期E80B卷 632-638页

作者： Lee, SS Jwa, JW Lee, HS Signal Processing Laboratory Korea Advance Institute Science and Technology Dongdaemun-Gu Seoul 130-012 20743 Cheongryangri-Dong South Korea

We propose an improved orthogonal frequency division multiplexing (OFDM) signal detector which uses the minimum mean-square error (MMSE) noise feedback equalization (NFE). The input bit stream is trellis-coded to form OFDM signal blocks and the maximal ratio combining (MRC) is adopted at the receiver in order to improve the performance of the detector. As a result, we obtain significantly improved detection performance compared with the conventional OFDM receivers as follows. Using the proposed MMSE-NFE in the receiver, we can obtain the performance gain of about 1.5 dB to 2 dB in symbol energy to noise power spectral density (E-s/N-O) for Doppler frequencies of f(d) = 20 and 100 Hz, respectively over the receiver with the MMSE linear equalization (LE) alone at symbol error rate (SER) of about 10(-3). With MRC and trellis coding, the performance gain of about 11 dB in E-s/N-O for f(d) = 20 and 100 Hz at SER of about 10(-3) is obtained.

关键词： frequency division multiplexing equalization diversity trellis-coded modulation noise feedback equalization

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Target detection in radar: Current status and future possibilities

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JOURNAL OF NAVIGATION 1997年第2期50卷 303-313页

作者： Li, VYF Miller, KM [a1 ](Hong Kong University of Science and Technology)[a2 ](Institute of Marine Studies University of Plymouth)Most of the radar systems used in operating marine vessel traffic management services experience problems such as track loss and track swap which may cause confusion to the traffic regulators and lead to potential hazards in the harbour operation. The reason is mainly due to the limited adaptive capabilities of the algorithms used in the detection process. The decision on whether a target is present is usually based on the amplitude information of the returning echoes. Such method has a low efficiency in discriminating between the target and clutter especially when the signal-to-noise ratio is low. With modern signal processing techniques more information can be extracted from the radar return signals and the tracking parameters of the previous scan. The objectives of this paper are to review the methods which are currently adopted in radar target identification identify techniques for extracting additional information and consider means of data analysis for deciding the presence of a target. Instead of employing traditional two-state logic it is suggested that the radar signal should be allocated in terms of threshold levels into fuzzy sets with its membership functions being related to the information extracted and the environment. Additional signal processing techniques are also suggested to explore pattern recognition aspects and discriminate features which are associated with a return signal from those of clutter.

Most of the radar systems used in operating marine vessel traffic management services experience problems, such as track loss and track swap, which may cause confusion to the traffic regulators and lead to potential hazards in the harbour operation. The reason is mainly due to the limited adaptive capabilities of the algorithms used in the detection process. The decision on whether a target is present is usually based on the amplitude information of the returning echoes. Such method has a low efficiency in discriminating between the target and clutter, especially when the signal-to-noise ratio is low. With modern signal processing techniques more information can be extracted from the radar return signals and the tracking parameters of the previous scan. The objectives of this paper are to review the methods which are currently adopted in radar target identification, identify techniques for extracting additional information and consider means of data analysis for deciding the presence of a target. Instead of employing traditional two-state logic, it is suggested that the radar signal should be allocated in terms of threshold levels into fuzzy sets with its membership functions being related to the information extracted and the environment. Additional signal processing techniques are also suggested to explore pattern recognition aspects and discriminate features which are associated with a return signal from those of clutter.

关键词： radar signal processing target detection

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Particle velocity and size estimation from two channel laser anemometry measurements

Particle velocity and size estimation from two channel laser...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： P. Handel A. Host-Madsen Signal Processing Laboratory Tampere University of Technology Tampere Finland Department of Information and Communications Gwangju Institute of Science and Technology Kwangju South Korea

A mathematical treatment of particle size and velocity estimation from two channel laser anemometry measurements is considered. Cramer-Rao bounds for the general case are derived, and the corresponding maximum likelihood estimator is analyzed through computer simulations. Low complexity correlation based estimators are derived and their performance is characterized. The results predicted by theory are illustrated by some numerical examples.

关键词： Velocity measurement Particle measurements Size measurement Background noise Frequency estimation signal processing Personal digital assistants Laser theory Maximum likelihood estimation Phase estimation

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Design of sparse FIR filters based on branch-and-bound algorithm

Design of sparse FIR filters based on branch-and-bound algor...

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Midwest Symposium on Circuits and Systems (MWSCAS)

作者： Young-Seog Song Yong Hoon Lee Signal Processing Laboratory Samsung Advanced Institute of Science and Technology South Korea Department of Electrical Engineering Korea Advanced Institute of Science and Technology Daejeon South Korea

Branch-and-bound algorithm is applied to the design of sparse FIR filters having intentionally zeroed tap positions. It is shown that this algorithm coupled with a suitable optimization technique for filter design can lead to an optimal sparse FIR filter satisfying given specifications. Design examples demonstrate that the proposed method requires less computation than the conventional optimization such as the subset selection method.

关键词： Finite impulse response filter Algorithm design and analysis signal processing algorithms Design optimization Integer linear programming Design methodology signal design Delay Narrowband Wideband

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Performance of the H.263 Video Compression Standard

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Journal of VLSI signal processing Systems for signal, Image, and Video technology 1997年第2-3期17卷 101-111页

作者： Girod, Bernd Steinbach, Eckehard Färber, Nikolaus Telecommunications Institute University of Erlangen-Nuremberg 91058 Erlangen Cauerstrasse 7 Germany Georgia Institute of Technology United States University of Hannover Germany Inst. F. Theor. N. University of Hannover Germany Massachussetts Inst. of Technology Cambridge MA United States Research Laboratory of Electronics United States Department of Media Technology Media Laboratory Germany Department of Computer Graphics Germany Academy of Media Arts Cologne Germany Computer Science Section Cologne University Germany Digital Signal Processing Group Georgia Institute of Technology Atlanta GA United States Dept. of Elec. Eng./Telecom. University of Erlangen-Nuremberg Germany Telecommunications Institute Germany Vivo Software Inc. Waltham MA United States University of Karlsruhe Germany University of Essex United Kingdom ESIEE Paris France Image Communication Group Telecommunications Institute University of Erlangen-Nuremberg Germany University of Munich Germany Telecommunications Institute University of Erlangen-Nuremberg Germany Image Communication Group

The draft international standard ITU-T H.263 is closely related to the well known and widely used ITU-T Recommendation H.261. However, H.263 does provide the same subjective image quality at less than half the bit-rate. In this paper we investigate to what extend single enhancements of H.263 contribute to this performance gain, and consider the trade-off quality vs. complexity. Based on typical test sequences, H.263 with its various modes is compared to H.261 on the basis of rate distortion curves at bit-rates up to 128 kbps. At 64 kbps, the performance gain of H.263 in its default mode compared to H.261 is approximately 2 dB. This improvement is achieved with only little increase of complexity, and is mainly due to more accurate motion compensation with half-pel accuracy. Considering the trade-off quality vs. complexity, the combination of the optional coding-modes "Advanced prediction mode" and "PB-frames mode" is a good compromise, resulting in an additional performance gain of 1.5 dB PSNR at 64 kbps. The "Syntax-based arithmetic coding mode" on the other hand, offers only a very small performance gain (0.1 dB at 64 kbps) for its increased computational complexity. Results from profiling an H.263 software codec are presented in order to support complexity considerations of the optional coding-modes.

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The RASSP Program: Origin, Concepts, and Status: An Introduction to the Issue

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Journal of VLSI signal processing Systems for signal, Image, and Video technology 1997年第1-2期15卷 7-27页

作者： Richards, Mark A. Gadient, Anthony Frank, Geoffrey A. Harr, Randolph Georgia Tech. Research Institute Atlanta GA 30332-0856 United States South Carolina Research Authority Charleston SC 29464 5300 International Blvd. United States Research Triangle Institute Research Triangle Park NC P.O. Box 12194 United States Def. Adv. Research Projects Agency Electronics Technology Office Arlington VA 22203-1714 3701 N. Fairfax Drive United States Georgia Tech. United States Stanford University United States Sensors Electromagnetic Applic. Lab. Georgia Tech. Research Institute United States Signal Processing Branch SEAL's Radar Systems Division United States Georgia Tech's Sch. Elec. Comp. Eng. Georgia State of Georgia United States Atlanta Section IEEE United States University of Virginia United States Wright State University United States Carnegie Mellon University United States United States Air Force (USAF) United States AF Wright Aero. Avionics Laboratory South Carolina Research Authority Advanced Technology Group United States Intl. Electro-Tech. Commn. W. Natl. Electronics Mfg. Inititative Sch. of Elec. and Comp. Engineering Georgia Institute of Technology United States Inst. of Elec. and Electronics Eng. Association for Computing Machinery Amer. Assoc. for Artif. Intelligence United States University of North Carolina Chapel Hill NC United States Research Triangle Institute United States Electronics Technology Office United States Synopsys Corp.'s Logic Modeling Grp. United States Case Western Reserve University United States

The Rapid Prototyping of Application Specific signal Processors (RASSP) program is a multi-year DARPA/Tri-Service initiative intended to dramatically improve the process by which complex digital systems, particularly embedded digital signal processors, are designed, manufactured, upgraded, and supported. This paper reviews the genesis of the RASSP program, considering both the problems that defined the need for the program, and the historical conditions under which it began. The RASSP program is then presented from two viewpoints. The first is programmatic, covering the goals and constraints of the program, and describing the roles of the various program participants. The second is technical, covering the major concepts upon which the developing RASSP approach to design is based and showing how the detailed technical discussions contained in the other papers in this issue of the Journal of VLSI signal processing relate to one another and fit into an overall development concept. The paper closes with a review of the status of the program as of this writing (Summer 1996).

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Virtual musical instruments - natural sound using physical models

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Organised Sound 1996年第2期1卷 75-75页

作者： Valimaki, Vesa Takala, Tapio Helsinki University of Technology Laboratory of Acoustics and Audio Signal Processing Otakaari 5A FIN-02150 Espoo Finland Helsinki University of Technology Department of Computer Science Otakaari 1 FIN-02150 Espoo Finland

Physical modelling of musical instruments is an exciting new paradigm in digital sound synthesis. The basic idea is to imitate the sound production mechanism of an acoustic musical instrument using a computer program. The sound produced by such a model will automatically resemble that of the real instrument, if the model has been devised in a proper way. In this article we review the history and present techniques of physical modelling. It appears that the many seemingly very different modelling methods try to achieve the same result: to simulate the solutions of the wave equation in a simplified manner. We concentrate on the digital waveguide modelling technique which has gained much popularity among both researchers and engineers in the music technology industry. The benefits and drawbacks of the new technology are considered, and concurrent research topics are discussed. The physical modelling approach offers many new applications, especially in the fields of multimedia and virtual reality. © 1996, Cambridge University Press. All rights reserved.

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Performance of state space multi-sensor track fusion with model mismatch 1

Performance of state space multi-sensor track fusion with mo...

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1st Australian Data Fusion Symposium (ADFS-96)

作者： Krieg, ML Gray, DA Microwave Radar Division Defence Science and Technology Organisation PO Box 1500 Salisbury 5108 SA Australia Cooperative Research Centre for Sensor Signal and Information Processing Levels SA Australia Dept of Electrical and Electronic Engineering University of Adelaide Adelaide SA Australia

ISBN: (纸本)0780336011

Successful tracking requires assumptions to model the target's behaviour and sensor characteristics. The sensitivity of multi-sensor tracking filters to errors in these models is of particular interest to the designer. We consider the specific case of a dual sensor Kalman tracker and compare its theoretical sensitivity to process and measurement model mismatch with that of a single sensor Kalman tracker, confirming our results with simulations. We introduce the notion of a fusion gain as a comparative measure of tracking performance, and the concept of a mismatch factor as a comparative measure of sensitivity, between the dual and single sensor trackers.

关键词： Sensor data fusion

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Adaptive ionospheric distortion correction techniques for HF skywave radar

Adaptive ionospheric distortion correction techniques for HF...

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IEEE National Conference on radar

作者： Y.I. Abramovich S.J. Anderson I.S.D. Solomon Cooperative Research Centre for Sensor Signal and Information Processing SA Australia High Frequency Radar Division Defence Science and Technology Organisation Salisbury SA Australia

This paper addresses the problem of adaptive decontamination of HF radar signals corrupted by propagation through the ionosphere. Ensembles of radar returns from adjacent resolution cells experiencing highly correlated contamination are used to provide stochastic identification of multiplicative phase smearing, as distinct from the occurrence of superimposed multimode returns. A MUSIC-type procedure is elaborated for estimating the phase path smearing function. For the multimode contamination situation, a constrained spectral deconvolution approach is developed to estimate the corresponding single-mode spectrum. Simulations and real data are used to demonstrate the efficiency of the proposed methods.

关键词： Hafnium radar Contamination Distortion Decontamination Ionosphere signal resolution Stochastic processes Phase estimation Deconvolution

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Track Fusion in the Presence of an Interference

Track Fusion in the Presence of an Interference

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International Symposium on signal processing and Its Applications (ISSPA)

作者： M.L. Krieg D.A. Gray Microwave Radar Division Defence Science and Technology Organisation Salisbury SA Australia Dept of Electrical and Electronic Engineering University of Adelaide Adelaide SA Australia Signal and Information Processing Cooperative Research Centre for Sensor Signal and Information Processing SA Australia

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