Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680053
M. Médard
We consider using DS-CDMA over channels which decorrelate in frequency. We allow the bandwidth to increase while maintaining a fixed total average power. The bandwidth over which we transmit is divided into several slices, each of which has its own spreading sequence. We show that for a large bandwidth DS-CDMA spreading is not advantageous when the channel truly decorrelates in frequency or when the channel bandwidth slices are correlated but not jointly estimated.
{"title":"Bound on mutual information for DS-CDMA spreading over independent fading channels","authors":"M. Médard","doi":"10.1109/ACSSC.1997.680053","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680053","url":null,"abstract":"We consider using DS-CDMA over channels which decorrelate in frequency. We allow the bandwidth to increase while maintaining a fixed total average power. The bandwidth over which we transmit is divided into several slices, each of which has its own spreading sequence. We show that for a large bandwidth DS-CDMA spreading is not advantageous when the channel truly decorrelates in frequency or when the channel bandwidth slices are correlated but not jointly estimated.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"101 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":"133187494","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.1997.679084
G. Erten, F. Salam
Contemporary computing platforms fail to deliver the computational density required for many real-time image processing tasks. On the other hand, even the simplest of living systems are able to perceive and interpret their environment effortlessly using a conglomerate of slow and inaccurate neurons in parallel. Motivated by this observation as well as the cellular neural network paradigm, this paper presents an integrated sensor processor architecture that captures the local connectivity patterns of the vertebrate retina in silicon to perform parallel programmable iconic image operations. Results are presented from simulation of this new cellular network paradigm.
{"title":"Cellular mixed signal pixel array for real time image processing","authors":"G. Erten, F. Salam","doi":"10.1109/ACSSC.1997.679084","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679084","url":null,"abstract":"Contemporary computing platforms fail to deliver the computational density required for many real-time image processing tasks. On the other hand, even the simplest of living systems are able to perceive and interpret their environment effortlessly using a conglomerate of slow and inaccurate neurons in parallel. Motivated by this observation as well as the cellular neural network paradigm, this paper presents an integrated sensor processor architecture that captures the local connectivity patterns of the vertebrate retina in silicon to perform parallel programmable iconic image operations. Results are presented from simulation of this new cellular network paradigm.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"4 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":"133190917","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.1997.679097
J. Ward, G. Hatke
Space-time adaptive processing (STAP) offers the potential for improved airborne surveillance radar performance in environments dominated by ground clutter and interference. This paper applies the GAMMA (generalized adaptive multidimensional monopulse algorithm) parameter estimation approach to solve for the target azimuth and Doppler for a STAP radar The GAMMA algorithm converts the maximization of the maximum likelihood objective function into a problem of finding a joint solution of a pair of two-variable polynomial equations. This obviates the computationally complex task of searching for a maximum over the array manifold. Simulations results comparing the GAMMA produced estimates to the Cramer-Rao bound are given, showing the near statistical efficiency of the new algorithm.
{"title":"An efficient rooting algorithm for simultaneous angle and Doppler estimation with space-time adaptive processing radar","authors":"J. Ward, G. Hatke","doi":"10.1109/ACSSC.1997.679097","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679097","url":null,"abstract":"Space-time adaptive processing (STAP) offers the potential for improved airborne surveillance radar performance in environments dominated by ground clutter and interference. This paper applies the GAMMA (generalized adaptive multidimensional monopulse algorithm) parameter estimation approach to solve for the target azimuth and Doppler for a STAP radar The GAMMA algorithm converts the maximization of the maximum likelihood objective function into a problem of finding a joint solution of a pair of two-variable polynomial equations. This obviates the computationally complex task of searching for a maximum over the array manifold. Simulations results comparing the GAMMA produced estimates to the Cramer-Rao bound are given, showing the near statistical efficiency of the new algorithm.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"155 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":"133040317","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.1997.680570
Jonghoon Chun, J. Chun, T. Johnson
We present a fast nonlinear filtering algorithm that can track a single target in multiple clutter points. The proposed algorithm propagates the entire conditional probability density functions recursively, but in a computationally efficient manner using either the fast Fourier transform or the fast discrete wavelet-based convolution. Our algorithm does not need the explicit data association step which is in most multiple target tracking filters, and therefore appears to be more natural and robust.
{"title":"A fast nonlinear filtering algorithm for tracking a target in clutter using the wavelet transform","authors":"Jonghoon Chun, J. Chun, T. Johnson","doi":"10.1109/ACSSC.1997.680570","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680570","url":null,"abstract":"We present a fast nonlinear filtering algorithm that can track a single target in multiple clutter points. The proposed algorithm propagates the entire conditional probability density functions recursively, but in a computationally efficient manner using either the fast Fourier transform or the fast discrete wavelet-based convolution. Our algorithm does not need the explicit data association step which is in most multiple target tracking filters, and therefore appears to be more natural and robust.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"46 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":"123189744","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.1997.680440
Yung-Cheng Lo, J. Dill, A. Lindsey
Circular trellis-coded modulation (CTCM) is a trellis coding with a state permutation structure which not only retains the properties of traditional trellis-coded modulation (TCM) but also allows more efficient systematic trellis construction. The embedded state-permuted characteristic guarantees that the starting and ending states for a given input symbol block are the same. This property is termed the "state constraint". The state transitions form a wrap-around path which depends on each distinct input sequence. However, a cyclic shift of the input sequence compels a cyclic shift of its state transition sequence. The grouping of these cyclically shifting state-transition sets reduces the encoding speed and simplifies performance analysis.
{"title":"High dimensional circular trellis-coded modulation","authors":"Yung-Cheng Lo, J. Dill, A. Lindsey","doi":"10.1109/ACSSC.1997.680440","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680440","url":null,"abstract":"Circular trellis-coded modulation (CTCM) is a trellis coding with a state permutation structure which not only retains the properties of traditional trellis-coded modulation (TCM) but also allows more efficient systematic trellis construction. The embedded state-permuted characteristic guarantees that the starting and ending states for a given input symbol block are the same. This property is termed the \"state constraint\". The state transitions form a wrap-around path which depends on each distinct input sequence. However, a cyclic shift of the input sequence compels a cyclic shift of its state transition sequence. The grouping of these cyclically shifting state-transition sets reduces the encoding speed and simplifies performance analysis.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"162 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":"124536411","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.1997.680368
S. Casey
Given, noisy data from a periodic point process that satisfies certain conditions, least squares procedures can be used to solve for maximum likelihood estimates of the period. Under more general conditions, Fourier analytic methods, e.g., Wiener's periodogram, can be used to solve for estimates which are approximately maximum likelihood. However, these methods break down when the data has increasing numbers of missing observations. Juxtaposed with these methods, number theoretic methods provide parameter estimations that, while not being maximum likelihood, can be used as initialization in an algorithm that achieves the Cramer-Rao bound for moderate noise levels. We describe the conditions under which the least squares procedures and Fourier analytic methods do not produce estimates close to maximum likelihood, and show that the number theoretic methods provide a reliable estimate in these cases. We also discuss the type of data for which the number theoretic methods fail to produce good estimates.
{"title":"Sampling issues in least squares, Fourier analytic, and number theoretic methods in parameter estimation","authors":"S. Casey","doi":"10.1109/ACSSC.1997.680368","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680368","url":null,"abstract":"Given, noisy data from a periodic point process that satisfies certain conditions, least squares procedures can be used to solve for maximum likelihood estimates of the period. Under more general conditions, Fourier analytic methods, e.g., Wiener's periodogram, can be used to solve for estimates which are approximately maximum likelihood. However, these methods break down when the data has increasing numbers of missing observations. Juxtaposed with these methods, number theoretic methods provide parameter estimations that, while not being maximum likelihood, can be used as initialization in an algorithm that achieves the Cramer-Rao bound for moderate noise levels. We describe the conditions under which the least squares procedures and Fourier analytic methods do not produce estimates close to maximum likelihood, and show that the number theoretic methods provide a reliable estimate in these cases. We also discuss the type of data for which the number theoretic methods fail to produce good estimates.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"119 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":"125215268","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.1997.679100
S. Barbarossa, R. Mameli, A. Scaglione
The parameter estimation of polynomial-phase signals (PPS) has been extensively studied in the literature in view of possible important applications in remote sensing as well as in telecommunications. However, the detection of PPS has not received similar attention. We propose and analyze an adaptive method for the detection of PPS embedded in white Gaussian noise based on the use of the so called product high order ambiguity function.
{"title":"Adaptive detection of polynomial-phase signals embedded in noise using high-order ambiguity functions","authors":"S. Barbarossa, R. Mameli, A. Scaglione","doi":"10.1109/ACSSC.1997.679100","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679100","url":null,"abstract":"The parameter estimation of polynomial-phase signals (PPS) has been extensively studied in the literature in view of possible important applications in remote sensing as well as in telecommunications. However, the detection of PPS has not received similar attention. We propose and analyze an adaptive method for the detection of PPS embedded in white Gaussian noise based on the use of the so called product high order ambiguity function.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"14 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":"134176378","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.1997.680369
Tsung-Hsien Liu, J. Mendel
Virtual-ESPRIT (VESPA) imposes a slight constraint on the array i.e. only a pair of identical sensors are required. We follow the classical procedure to define the sensitivity of VESPA with respect to each model parameter, and derive closed forms for the sensitivity formulas. We justify our derivations by comparing the theoretical formulas with the results from Monte Carlo simulations. Additionally, we demonstrate, by simulations, that VESPA is more robust to model mismatches than ESPRIT in most situations.
{"title":"The robustness of virtual-ESPRIT against model errors","authors":"Tsung-Hsien Liu, J. Mendel","doi":"10.1109/ACSSC.1997.680369","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680369","url":null,"abstract":"Virtual-ESPRIT (VESPA) imposes a slight constraint on the array i.e. only a pair of identical sensors are required. We follow the classical procedure to define the sensitivity of VESPA with respect to each model parameter, and derive closed forms for the sensitivity formulas. We justify our derivations by comparing the theoretical formulas with the results from Monte Carlo simulations. Additionally, we demonstrate, by simulations, that VESPA is more robust to model mismatches than ESPRIT in most situations.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"94 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":"133677688","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.1997.680576
Miguel, Lagunas, A. Pérez-Neira, Josep Vidal
The presence of a sequence detector in the baseline architecture for base stations for mobile communications has become a standard. Also the use of coding allows the baseband detector to work at very low signal to noise ratios. When spatial diversity is included in the front-end, the joint design of the beamformer, matched filter and the desired impulse response DIR of the Viterbi equalizer VE is mandatory. This work describes the joint design of these stages when the matched DIR response has priority in the maximization of the signal to noise plus interferences ratio at the input of the VE.
{"title":"Joint beamforming and Viterbi equalizer in wireless communications","authors":"Miguel, Lagunas, A. Pérez-Neira, Josep Vidal","doi":"10.1109/ACSSC.1997.680576","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680576","url":null,"abstract":"The presence of a sequence detector in the baseline architecture for base stations for mobile communications has become a standard. Also the use of coding allows the baseband detector to work at very low signal to noise ratios. When spatial diversity is included in the front-end, the joint design of the beamformer, matched filter and the desired impulse response DIR of the Viterbi equalizer VE is mandatory. This work describes the joint design of these stages when the matched DIR response has priority in the maximization of the signal to noise plus interferences ratio at the input of the VE.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"52 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":"133721177","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.1997.680443
Alan Gatherer, Michael O. Polley
A discrete multitone signal has a much higher peak to average ratio than a comparable single tone modulation signal. Therefore a DMT transmitter has to either have a significantly more expensive analog front end (both in terms of the DAC, the analog filter and line driver) or it has to control the amount of clipping. We describe two general techniques for clipping control and present performance comparisons to previous techniques.
{"title":"Controlling clipping probability in DMT transmission","authors":"Alan Gatherer, Michael O. Polley","doi":"10.1109/ACSSC.1997.680443","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680443","url":null,"abstract":"A discrete multitone signal has a much higher peak to average ratio than a comparable single tone modulation signal. Therefore a DMT transmitter has to either have a significantly more expensive analog front end (both in terms of the DAC, the analog filter and line driver) or it has to control the amount of clipping. We describe two general techniques for clipping control and present performance comparisons to previous techniques.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"21 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":"114780325","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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