Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.679071
S. Ahmadi, A.S. Spenias
This paper addresses the design, development, evaluation, and implementation of efficient low bit rate speech coding algorithms based on the sinusoidal model. A series of algorithms have been developed for pitch frequency determination and voicing detection, simultaneous modeling of the sinusoidal amplitudes and phases, and mid-frame interpolation. An improved sinusoidal phase matching algorithm is presented, where short-time sinusoidal phases are approximated using an elaborate combination of linear prediction, spectral sampling, delay compensation, and phase correction techniques. A voicing-dependent perceptual split vector quantization scheme is used to encode the sinusoidal amplitudes. The perceptual properties of the human auditory system are effectively exploited in the developed algorithms. The algorithms have been successfully integrated into a 2.4 kbps sinusoidal coder. The performance of the 2.4 kbps coder has been evaluated in terms of subjective tests such as the mean opinion score and the diagnostic rhyme test, as well as some perceptually-motivated objective distortion measures. Performance analysis on a large speech database indicates that the use of the proposed algorithms resulted in considerable improvement in temporal and spectral signal matching, as well as improved subjective quality of the reproduced speech.
{"title":"Sinusoidal speech coding at 2.4 kbps using an improved phase matching algorithm","authors":"S. Ahmadi, A.S. Spenias","doi":"10.1109/ACSSC.1997.679071","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679071","url":null,"abstract":"This paper addresses the design, development, evaluation, and implementation of efficient low bit rate speech coding algorithms based on the sinusoidal model. A series of algorithms have been developed for pitch frequency determination and voicing detection, simultaneous modeling of the sinusoidal amplitudes and phases, and mid-frame interpolation. An improved sinusoidal phase matching algorithm is presented, where short-time sinusoidal phases are approximated using an elaborate combination of linear prediction, spectral sampling, delay compensation, and phase correction techniques. A voicing-dependent perceptual split vector quantization scheme is used to encode the sinusoidal amplitudes. The perceptual properties of the human auditory system are effectively exploited in the developed algorithms. The algorithms have been successfully integrated into a 2.4 kbps sinusoidal coder. The performance of the 2.4 kbps coder has been evaluated in terms of subjective tests such as the mean opinion score and the diagnostic rhyme test, as well as some perceptually-motivated objective distortion measures. Performance analysis on a large speech database indicates that the use of the proposed algorithms resulted in considerable improvement in temporal and spectral signal matching, as well as improved subjective quality of the reproduced speech.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116218456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680425
R. L. Murray, A. Papandreou-Suppappola, G. Boudreaux-Bartels
We propose a new higher order time-frequency representation (TFR), the higher order generalized warped Wigner distribution (HOG-WD), by warping the higher order Wigner distribution. The HOG-WD is important for analyzing signals with dispersive instantaneous frequency characteristics. In this paper, we (i) provide a HOG-WD formulation, (ii) give important special cases of the HOG-WD based on different warpings, (iii) discuss alternative HOG-WD formulations in terms of a 1-D generalized transform and in terms of a generalized higher order ambiguity function, (iv) discuss some desirable properties of the HOG-WD, and (v) define a higher order, generalized (alternating sign) frequency-shift covariant class of TFRs based upon smoothed versions of the HOG-WD.
{"title":"New time-frequency representations: higher order warped Wigner distributions","authors":"R. L. Murray, A. Papandreou-Suppappola, G. Boudreaux-Bartels","doi":"10.1109/ACSSC.1997.680425","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680425","url":null,"abstract":"We propose a new higher order time-frequency representation (TFR), the higher order generalized warped Wigner distribution (HOG-WD), by warping the higher order Wigner distribution. The HOG-WD is important for analyzing signals with dispersive instantaneous frequency characteristics. In this paper, we (i) provide a HOG-WD formulation, (ii) give important special cases of the HOG-WD based on different warpings, (iii) discuss alternative HOG-WD formulations in terms of a 1-D generalized transform and in terms of a generalized higher order ambiguity function, (iv) discuss some desirable properties of the HOG-WD, and (v) define a higher order, generalized (alternating sign) frequency-shift covariant class of TFRs based upon smoothed versions of the HOG-WD.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116220298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.679060
W. Yang, Guanghan Xu
Smart antennas have the potential to substantially increase the range of base stations and boost the signal to interference plus noise ratios of signals. In this paper we study the problem of downlink weighting vector design, and give the optimal power assignment when the orientations of the weighting vectors are known. Also four criteria for the optimal weighting vector design are given. Simulation results have shown the improvement offered by the optimal power assignment method studied here.
{"title":"Design of smart antenna downlink weighting vectors","authors":"W. Yang, Guanghan Xu","doi":"10.1109/ACSSC.1997.679060","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679060","url":null,"abstract":"Smart antennas have the potential to substantially increase the range of base stations and boost the signal to interference plus noise ratios of signals. In this paper we study the problem of downlink weighting vector design, and give the optimal power assignment when the orientations of the weighting vectors are known. Also four criteria for the optimal weighting vector design are given. Simulation results have shown the improvement offered by the optimal power assignment method studied here.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116291380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680362
S. Yazji, B. Lumetta, Magdy Bayoumi, Bertrand Zavidovique
An algorithmic specific architecture has been developed based on the newly introduced band-matching algorithm (BDMA) for computing motion vectors. The BDMA offers better performance than both the fixed size and variable size block matching algorithms as it uses less vectors and only processes the relevant parts of the image instead of the whole image. The main modules of the BDMA architecture are the encoder and decoder. The memory in the encoder is classified into three types: storing images, storing the image of difference, storing the bands. The first memory is arranged in parallel banks which will enhance the performance considerably. In the second memory, registers are used for temporary storage during filtering. The third memory is used for storing the bands. A single code book is employed to identify the type of edges.
{"title":"A motion-estimation architecture based on band-matching","authors":"S. Yazji, B. Lumetta, Magdy Bayoumi, Bertrand Zavidovique","doi":"10.1109/ACSSC.1997.680362","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680362","url":null,"abstract":"An algorithmic specific architecture has been developed based on the newly introduced band-matching algorithm (BDMA) for computing motion vectors. The BDMA offers better performance than both the fixed size and variable size block matching algorithms as it uses less vectors and only processes the relevant parts of the image instead of the whole image. The main modules of the BDMA architecture are the encoder and decoder. The memory in the encoder is classified into three types: storing images, storing the image of difference, storing the bands. The first memory is arranged in parallel banks which will enhance the performance considerably. In the second memory, registers are used for temporary storage during filtering. The third memory is used for storing the bands. A single code book is employed to identify the type of edges.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126218550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.679125
S. Venkatesan, V. Anantharam
Consider a finite number of agents interconnected by an arbitrary network of independent, point-to-point, discrete memoryless channels. The agents wish to generate common randomness by interactive communication over the network. Our main result is an exact characterization of the common randomness capacity of such a network, i.e. the maximum number of bits of randomness that all the agents can agree on, per step of communication. As a by-product, we also obtain a description by linear inequalities of the blocking-type polyhedron whose extreme points are precisely the incidence vectors of all arborescences in a digraph, with a prescribed root of out-degree 1.
{"title":"The common randomness capacity of a finite network of channels","authors":"S. Venkatesan, V. Anantharam","doi":"10.1109/ACSSC.1997.679125","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679125","url":null,"abstract":"Consider a finite number of agents interconnected by an arbitrary network of independent, point-to-point, discrete memoryless channels. The agents wish to generate common randomness by interactive communication over the network. Our main result is an exact characterization of the common randomness capacity of such a network, i.e. the maximum number of bits of randomness that all the agents can agree on, per step of communication. As a by-product, we also obtain a description by linear inequalities of the blocking-type polyhedron whose extreme points are precisely the incidence vectors of all arborescences in a digraph, with a prescribed root of out-degree 1.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126562627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680556
P. Flikkema
The additional dimensionality and bandwidth of direct-sequence spread spectrum signaling can be used to provide multiple access and exploit multipath in wireless communication. However, the severely spread channels that will be encountered in broadband wireless applications, combined with bandwidth limitations, motivates the use of additional receiver processing to provide improved performance at moderate spreading gains. Spread spectrum with simultaneous RAKE combining and ISI cancellation is explored. A received signal model is presented that captures the general time-varying multipath/multi-user case. Linear detectors are studied; in particular, results are shown for a correlation detector supplying tentative decisions to a RAKE detector working in tandem with a decision feedforward/feedback structure. The performance of this method is compared with both classical RAKE detection and a RAKE performance bound. The results show significant gains for typical multipath channels and suggest directions for further study of joint spread-spectrum and symbol-rate receiver processing.
{"title":"Multipath combining/cancelling DS spread spectrum detection","authors":"P. Flikkema","doi":"10.1109/ACSSC.1997.680556","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680556","url":null,"abstract":"The additional dimensionality and bandwidth of direct-sequence spread spectrum signaling can be used to provide multiple access and exploit multipath in wireless communication. However, the severely spread channels that will be encountered in broadband wireless applications, combined with bandwidth limitations, motivates the use of additional receiver processing to provide improved performance at moderate spreading gains. Spread spectrum with simultaneous RAKE combining and ISI cancellation is explored. A received signal model is presented that captures the general time-varying multipath/multi-user case. Linear detectors are studied; in particular, results are shown for a correlation detector supplying tentative decisions to a RAKE detector working in tandem with a decision feedforward/feedback structure. The performance of this method is compared with both classical RAKE detection and a RAKE performance bound. The results show significant gains for typical multipath channels and suggest directions for further study of joint spread-spectrum and symbol-rate receiver processing.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125637532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680579
B. Himed, W. Melvin
We use monostatic data obtained from the Multichannel Airborne Radar Measurements (MCARM) program to conduct a comparative analysis of various space-time adaptive processing techniques. Specifically, we consider reduced-dimension and reduced-rank methods. The measured data analysis shows the significance of training sample selection, effects of nonhomogeneity in the clutter data, sensitivity of certain classes of adaptive filters to the rank of the measured clutter signal and suitability of the various approaches.
{"title":"Analyzing space-time adaptive processors using measured data","authors":"B. Himed, W. Melvin","doi":"10.1109/ACSSC.1997.680579","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680579","url":null,"abstract":"We use monostatic data obtained from the Multichannel Airborne Radar Measurements (MCARM) program to conduct a comparative analysis of various space-time adaptive processing techniques. Specifically, we consider reduced-dimension and reduced-rank methods. The measured data analysis shows the significance of training sample selection, effects of nonhomogeneity in the clutter data, sensitivity of certain classes of adaptive filters to the rank of the measured clutter signal and suitability of the various approaches.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122008236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.679115
K. Abed-Meraim, Y. Hua
Passive localization of narrowband sources in the spherical coordinates (azimuth, elevation, and range) is considered. A new method which proceeds in two steps and uses only the second order statistics (SOS) of the observations collected from a centro-symmetric cross-array is introduced. The first step is a signal pre-processing which consists in the computation of some properly chosen spatial correlation sequences of the observed signal. The correlation coefficients are shown to be superimposed exponential sequences and their frequencies are nonlinear functions of azimuths, elevations and the ranges of the source signals. The second step consists in the estimation of the frequency components using the subspace rotation invariance (also known as ESPRIT and matrix pencils) technique. This method, however requires a correct parameter pairing (or eigenvalue association) to achieve a consistent estimation of the signal parameters. Several pairing techniques are considered. The source azimuths, elevations, and ranges are then calculated from the estimated frequency components. The effectiveness of the proposed method is illustrated by some numerical simulations.
{"title":"3-D near field source localization using second order statistics","authors":"K. Abed-Meraim, Y. Hua","doi":"10.1109/ACSSC.1997.679115","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679115","url":null,"abstract":"Passive localization of narrowband sources in the spherical coordinates (azimuth, elevation, and range) is considered. A new method which proceeds in two steps and uses only the second order statistics (SOS) of the observations collected from a centro-symmetric cross-array is introduced. The first step is a signal pre-processing which consists in the computation of some properly chosen spatial correlation sequences of the observed signal. The correlation coefficients are shown to be superimposed exponential sequences and their frequencies are nonlinear functions of azimuths, elevations and the ranges of the source signals. The second step consists in the estimation of the frequency components using the subspace rotation invariance (also known as ESPRIT and matrix pencils) technique. This method, however requires a correct parameter pairing (or eigenvalue association) to achieve a consistent estimation of the signal parameters. Several pairing techniques are considered. The source azimuths, elevations, and ranges are then calculated from the estimated frequency components. The effectiveness of the proposed method is illustrated by some numerical simulations.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121437282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680367
K. McDonald, R. Blum
Impulsive interference has been measured previously in some wireless communication environments. Physically-based impulsive interference models have been lacking for cases where the antenna elements in an array are closely spaced. Such cases are important when spatial processing is employed. In these closely-spaced element cases, the interference observations may be statistically dependent from antenna to antenna. A model for these closely-spaced element cases is developed using some ideas originally proposed by David Middleton. The model developed here is very general and so it appears to be applicable to a wide variety of physical situations. It assumes interference sources which are Poisson distributed in space and time, and it includes an additive Gaussian background component.
{"title":"A physically-based impulsive noise model for array observations","authors":"K. McDonald, R. Blum","doi":"10.1109/ACSSC.1997.680367","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680367","url":null,"abstract":"Impulsive interference has been measured previously in some wireless communication environments. Physically-based impulsive interference models have been lacking for cases where the antenna elements in an array are closely spaced. Such cases are important when spatial processing is employed. In these closely-spaced element cases, the interference observations may be statistically dependent from antenna to antenna. A model for these closely-spaced element cases is developed using some ideas originally proposed by David Middleton. The model developed here is very general and so it appears to be applicable to a wide variety of physical situations. It assumes interference sources which are Poisson distributed in space and time, and it includes an additive Gaussian background component.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115839378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680521
T. Roxborough, S. Medidi, A. Sen
The channel assignment problem in a mobile cellular network is considered in this paper. The cellular network is most often modelled as a graph and the channel assignment problem is formulated as the coloring problem of that graph. The channel assignment problem in its most general form is NP-complete. Prior studies assume that the graph modelling the cellular network is an arbitrary graph. However, we show that the graph modelling the cellular network has a very regular structure and exploiting this regular structure, the channel assignment problem can be solved optimally in many cases. We also present an integer linear programming formulation of the channel assignment problem.
{"title":"On channel assignment problem in cellular networks","authors":"T. Roxborough, S. Medidi, A. Sen","doi":"10.1109/ACSSC.1997.680521","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680521","url":null,"abstract":"The channel assignment problem in a mobile cellular network is considered in this paper. The cellular network is most often modelled as a graph and the channel assignment problem is formulated as the coloring problem of that graph. The channel assignment problem in its most general form is NP-complete. Prior studies assume that the graph modelling the cellular network is an arbitrary graph. However, we show that the graph modelling the cellular network has a very regular structure and exploiting this regular structure, the channel assignment problem can be solved optimally in many cases. We also present an integer linear programming formulation of the channel assignment problem.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130458050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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