Pub Date : 1997-11-02DOI: 10.1109/ACSSC.1997.680433
A. Ranheim, P. Pelin
A new algorithm for multiuser detection in a DS-CDMA system is presented. Based on an algorithm originally developed in the array-processing context, it minimizes a weighted least-squares criterion, and detects one signal at a time. A performance analysis in terms of the bit-error rate is carried out, and demonstrates that the proposed method is asymptotically identical to the LMMSE-estimator, but without assuming or requiring any knowledge of the signal amplitudes. Only the desired user's signature sequence and timing is required. Both a batch and a recursive formulation of the algorithm is described and simulation results are included in addition to the analysis, to highlight the comparison to other methods.
{"title":"A decoupled WLS approach to DS-CDMA multiuser detection","authors":"A. Ranheim, P. Pelin","doi":"10.1109/ACSSC.1997.680433","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680433","url":null,"abstract":"A new algorithm for multiuser detection in a DS-CDMA system is presented. Based on an algorithm originally developed in the array-processing context, it minimizes a weighted least-squares criterion, and detects one signal at a time. A performance analysis in terms of the bit-error rate is carried out, and demonstrates that the proposed method is asymptotically identical to the LMMSE-estimator, but without assuming or requiring any knowledge of the signal amplitudes. Only the desired user's signature sequence and timing is required. Both a batch and a recursive formulation of the algorithm is described and simulation results are included in addition to the analysis, to highlight the comparison to other methods.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"17 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":"123471230","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.1997.680250
Bo Tao, M. Orchard
This paper presents an analysis of the block-decimated motion estimates and relates them to the underlying motion random field. It further parameterizes the scene intensity random field and the motion random field in terms of their correlation properties. Within this framework, we develop an algorithm to optimize the window for overlapped block motion compensation as a function of the model parameters. Through simulations, we demonstrate that the optimal window resulting from the parametric formulation offers performance comparable to the window deterministically optimized for the test sequence, and it offers more robust performance outside the training set. Finally, we apply our algorithm to adapt the overlapped window to match the temporally changing characteristics of the scene and motion fields. We demonstrate that for real-time applications, where the number of frames used for adapting the window is limited, our algorithm significantly outperforms the method introduced by Orchard and Sullivan (see IEEE Trans. Image Processing, vol.3, no.5, p.693-9, 1994).
{"title":"Window design for overlapped block motion compensation through statistical motion modeling","authors":"Bo Tao, M. Orchard","doi":"10.1109/ACSSC.1997.680250","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680250","url":null,"abstract":"This paper presents an analysis of the block-decimated motion estimates and relates them to the underlying motion random field. It further parameterizes the scene intensity random field and the motion random field in terms of their correlation properties. Within this framework, we develop an algorithm to optimize the window for overlapped block motion compensation as a function of the model parameters. Through simulations, we demonstrate that the optimal window resulting from the parametric formulation offers performance comparable to the window deterministically optimized for the test sequence, and it offers more robust performance outside the training set. Finally, we apply our algorithm to adapt the overlapped window to match the temporally changing characteristics of the scene and motion fields. We demonstrate that for real-time applications, where the number of frames used for adapting the window is limited, our algorithm significantly outperforms the method introduced by Orchard and Sullivan (see IEEE Trans. Image Processing, vol.3, no.5, p.693-9, 1994).","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"160 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":"122864142","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.1997.679127
Changlin Chen, J. Dill, Yung-Cheng Lo, A. Lindsey
The uniformity of a new trellis-coded modulation for spread spectrum communications, called high dimensional trellis-coded modulation (HDTCM) is studied. High dimensional trellis-coded modulation integrates a new block code with permuted state structure and a high dimensional signal constellation. It combines not only coding and modulation, but also PN spreading into one single process. The uniformity of the scheme enables us to choose an arbitrary reference during performance analysis which greatly simplifies the performance analysis. The paper proves that high dimensional trellis-coded modulation with a bi-orthogonal signal constellation is a uniform scheme. It further points out that the uniformity of the HDTCM scheme depends upon the uniformity of the signal constellation used.
{"title":"Uniformity of high dimensional trellis-coded modulation","authors":"Changlin Chen, J. Dill, Yung-Cheng Lo, A. Lindsey","doi":"10.1109/ACSSC.1997.679127","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679127","url":null,"abstract":"The uniformity of a new trellis-coded modulation for spread spectrum communications, called high dimensional trellis-coded modulation (HDTCM) is studied. High dimensional trellis-coded modulation integrates a new block code with permuted state structure and a high dimensional signal constellation. It combines not only coding and modulation, but also PN spreading into one single process. The uniformity of the scheme enables us to choose an arbitrary reference during performance analysis which greatly simplifies the performance analysis. The paper proves that high dimensional trellis-coded modulation with a bi-orthogonal signal constellation is a uniform scheme. It further points out that the uniformity of the HDTCM scheme depends upon the uniformity of the signal constellation used.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"35 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":"124259325","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.1997.680020
In-Seung Park, E. Powers
In this paper we describe the performance of a new adaptive HPA (high power amplifier) predistorter which utilizes indirect learning architecture. This approach eliminates the necessity of first developing a fixed model of the HPA inverse amplitude response and direct phase response, since such responses are determined adaptively. The performance of the proposed predistorter is demonstrated via the reduction of spectral spreading, comparison of received 64-QAM signal constellations with and without distortion, and the ability of the predistorter to adapt to perturbations of the HPA characteristics.
{"title":"An adaptive predistorter for high power amplifiers","authors":"In-Seung Park, E. Powers","doi":"10.1109/ACSSC.1997.680020","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.680020","url":null,"abstract":"In this paper we describe the performance of a new adaptive HPA (high power amplifier) predistorter which utilizes indirect learning architecture. This approach eliminates the necessity of first developing a fixed model of the HPA inverse amplitude response and direct phase response, since such responses are determined adaptively. The performance of the proposed predistorter is demonstrated via the reduction of spectral spreading, comparison of received 64-QAM signal constellations with and without distortion, and the ability of the predistorter to adapt to perturbations of the HPA characteristics.","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":"129785382","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.1997.679062
J. Treichler, M. Larimore
This paper examines the problem of demodulating time-dispersed digitally modulated signals with particular emphasis on two aspects, the all-digital implementation of such demodulators and the use of "blind" algorithms for initializing the demodulator in the absence of explicit training by the transmitter.
{"title":"Practical implementations of blind demodulators","authors":"J. Treichler, M. Larimore","doi":"10.1109/ACSSC.1997.679062","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679062","url":null,"abstract":"This paper examines the problem of demodulating time-dispersed digitally modulated signals with particular emphasis on two aspects, the all-digital implementation of such demodulators and the use of \"blind\" algorithms for initializing the demodulator in the absence of explicit training by the transmitter.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"23 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":"129390168","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.1997.679159
R. Sarmiento, C. Pulido, F. Tobajas, V. Armas, R. Esper-Chaín, J. López, J. Montiel-Nelson, A. Núñez
In this paper we present the design of a 2D discrete cosine transform (2D-DCT) processor and its implementation using 0.6 /spl mu/m GaAs technology. The architecture of the processor, that resembles an FCT-MMM (fast cosine transform-matrix matrix multiplication) architecture, was development using distributed arithmetic (DA) in order to reduce the area required. The processor has about 50k transistors and occupies an area of 31.8 mm/sup 2/. It is able to process 400 Mpixels per second and at a clock frequency of 600 MHz, which is far beyond the requirements for real time high definition moving pictures in the MPEG-2 standard. Special consideration is given to the implementation of a transposition RAM which constitutes the bottleneck of the algorithm. A 64 word/spl times/12 bit, 1 ns access time transposition RAM was developed using a new dynamic RAM cell.
{"title":"A 600 MHz 2D-DCT processor for MPEG applications","authors":"R. Sarmiento, C. Pulido, F. Tobajas, V. Armas, R. Esper-Chaín, J. López, J. Montiel-Nelson, A. Núñez","doi":"10.1109/ACSSC.1997.679159","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679159","url":null,"abstract":"In this paper we present the design of a 2D discrete cosine transform (2D-DCT) processor and its implementation using 0.6 /spl mu/m GaAs technology. The architecture of the processor, that resembles an FCT-MMM (fast cosine transform-matrix matrix multiplication) architecture, was development using distributed arithmetic (DA) in order to reduce the area required. The processor has about 50k transistors and occupies an area of 31.8 mm/sup 2/. It is able to process 400 Mpixels per second and at a clock frequency of 600 MHz, which is far beyond the requirements for real time high definition moving pictures in the MPEG-2 standard. Special consideration is given to the implementation of a transposition RAM which constitutes the bottleneck of the algorithm. A 64 word/spl times/12 bit, 1 ns access time transposition RAM was developed using a new dynamic RAM cell.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"2 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":"129592693","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.1997.679103
D. Wei, A. Bovik
We study the asymptotic behavior of the dual filters associated with biorthogonal spline wavelets (BSWs) and general biorthogonal Coifman wavelets (GBCWs). As the order of wavelet systems approaches infinity the BSW filters either diverge or converge to some non-ideal filters, the GBCW synthesis filters converge to an ideal halfband lowpass (HBLP) filter without exhibiting any Gibbs-like phenomenon, and a subclass of the analysis filters also converge to an ideal HBLP filter but with a one-sided Gibbs-like behavior. The two approximations of the ideal HBLP filter by Daubechies orthonormal wavelet filters and by the GBCW synthesis filters are also compared.
{"title":"Asymptotic convergence of biorthogonal wavelet filters","authors":"D. Wei, A. Bovik","doi":"10.1109/ACSSC.1997.679103","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679103","url":null,"abstract":"We study the asymptotic behavior of the dual filters associated with biorthogonal spline wavelets (BSWs) and general biorthogonal Coifman wavelets (GBCWs). As the order of wavelet systems approaches infinity the BSW filters either diverge or converge to some non-ideal filters, the GBCW synthesis filters converge to an ideal halfband lowpass (HBLP) filter without exhibiting any Gibbs-like phenomenon, and a subclass of the analysis filters also converge to an ideal HBLP filter but with a one-sided Gibbs-like behavior. The two approximations of the ideal HBLP filter by Daubechies orthonormal wavelet filters and by the GBCW synthesis filters are also compared.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"28 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":"128534414","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.1997.679187
M. Abe, M. Kawamata
This paper demonstrates a comparison of the convergence behavior of the IIR evolutionary digital filter (IIR-EDF), the LMS adaptive digital filter (LMS-ADF) and the adaptive digital filter based on the simple genetic algorithm (SGA-ADF) on a multiple-peak surface. In numerical examples, the authors use a reduced-order system identification to simulate a multiple-peak surface in which local minimum problems can be encountered. The experimental results show that the EDF adaptive algorithm can search the global minimum in the multiple-peak surface of these examples and has a smaller adaptation noise than the other algorithms.
{"title":"Comparison of the convergence of IIR evolutionary digital filters and other adaptive digital filters on a multiple-peak surface","authors":"M. Abe, M. Kawamata","doi":"10.1109/ACSSC.1997.679187","DOIUrl":"https://doi.org/10.1109/ACSSC.1997.679187","url":null,"abstract":"This paper demonstrates a comparison of the convergence behavior of the IIR evolutionary digital filter (IIR-EDF), the LMS adaptive digital filter (LMS-ADF) and the adaptive digital filter based on the simple genetic algorithm (SGA-ADF) on a multiple-peak surface. In numerical examples, the authors use a reduced-order system identification to simulate a multiple-peak surface in which local minimum problems can be encountered. The experimental results show that the EDF adaptive algorithm can search the global minimum in the multiple-peak surface of these examples and has a smaller adaptation noise than the other algorithms.","PeriodicalId":240431,"journal":{"name":"Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136)","volume":"10 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":"130536998","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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