Pub Date : 2008-07-06DOI: 10.1109/SPAWC.2008.4641565
Xu Chen, D. Schonfeld, A. Khokhar
In this paper, we propose a robust novel approach with closed-form estimator for object tracking based on a non-linear measurement model over time from a single sensor with arbitrary noise degradation. Relying on the widely-used dynamic motion model for arbitrary moving targets, tracking of moving objects can be formulated using received signal strength (RSS) measurements. We provide a closed-form solution that integrates localization and filtering for both an ideal channel as well as noisy channel. We first derive an exact linear model from the non-linear system of equations provided by the RSS measurements. We subsequently present an iterative method to estimate the unknown parameters and the error covariance matrix. Moreover, we prove that the estimator gives more accuracy when the number of samples increases. The Cramer-Rao bound (CRB) for the estimator are determined in Gaussian case. Computer simulation demonstrates that the proposed approach not only achieves more accuracy than traditional methods but also saves significant computation time.
{"title":"Robust closed-form localization of mobile targets using a single sensor based on a non-linear measurement model","authors":"Xu Chen, D. Schonfeld, A. Khokhar","doi":"10.1109/SPAWC.2008.4641565","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641565","url":null,"abstract":"In this paper, we propose a robust novel approach with closed-form estimator for object tracking based on a non-linear measurement model over time from a single sensor with arbitrary noise degradation. Relying on the widely-used dynamic motion model for arbitrary moving targets, tracking of moving objects can be formulated using received signal strength (RSS) measurements. We provide a closed-form solution that integrates localization and filtering for both an ideal channel as well as noisy channel. We first derive an exact linear model from the non-linear system of equations provided by the RSS measurements. We subsequently present an iterative method to estimate the unknown parameters and the error covariance matrix. Moreover, we prove that the estimator gives more accuracy when the number of samples increases. The Cramer-Rao bound (CRB) for the estimator are determined in Gaussian case. Computer simulation demonstrates that the proposed approach not only achieves more accuracy than traditional methods but also saves significant computation time.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133133312","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641558
Jianfeng Hu, Tiejun Lv
In this paper, a low complexity blind synchronization algorithm is proposed for ultra wideband (UWB) communication systems in the multipath environment. Using the first order statistics of the received signal, the proposed algorithm is carried out without aided data. The synchronization parameter and nuisance ones are separated from each other on account of the structure of the Vandermonde matrix, and their estimates are obtained by one-dimensional searching according to the orthogonality among vectors. During the searching process, relative path delays and attenuations come out as by-products. Most importantly, the proposed algorithm has a very low complexity, because the computational requirements are determined mainly by simple additions and inner products among vectors. Simulations and comparisons are performed to illustrate the promising performance of the proposed algorithm.
{"title":"A low-complexity blind synchronization algorithm for UWB systems","authors":"Jianfeng Hu, Tiejun Lv","doi":"10.1109/SPAWC.2008.4641558","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641558","url":null,"abstract":"In this paper, a low complexity blind synchronization algorithm is proposed for ultra wideband (UWB) communication systems in the multipath environment. Using the first order statistics of the received signal, the proposed algorithm is carried out without aided data. The synchronization parameter and nuisance ones are separated from each other on account of the structure of the Vandermonde matrix, and their estimates are obtained by one-dimensional searching according to the orthogonality among vectors. During the searching process, relative path delays and attenuations come out as by-products. Most importantly, the proposed algorithm has a very low complexity, because the computational requirements are determined mainly by simple additions and inner products among vectors. Simulations and comparisons are performed to illustrate the promising performance of the proposed algorithm.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115347864","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641602
C. Fernandes, G. Favier, J. Mota
A new method for estimating nonlinear instantaneous channels in a multiuser Code Division Multiple Access (CDMA) environment is presented in this paper. This kind of nonlinear models has important applications in the field of telecommunications, e.g. to model uplink channels in Radio Over Fiber multiuser communication systems. The proposed technique is based on the decomposition of a tensor composed of covariances of the chip-rate sampled received signals, the transmitted signals being assumed to be Phase Shift Keying (PSK) modulated. The considered tensor-based approach allows a great flexibility on the number of antennas and the spreading factor, which is particularly desirable when identifying nonlinear systems. Two blind channel estimation algorithms are considered: the Alternating Least Squares (ALS) algorithm and a non-iterative algorithm based on Eigenvalue Decompositions (EVD). The performance of the proposed estimation algorithms is illustrated by means of computer simulations.
{"title":"Blind estimation of nonlinear instantaneous channels in multiuser CDMA systems with PSK inputs","authors":"C. Fernandes, G. Favier, J. Mota","doi":"10.1109/SPAWC.2008.4641602","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641602","url":null,"abstract":"A new method for estimating nonlinear instantaneous channels in a multiuser Code Division Multiple Access (CDMA) environment is presented in this paper. This kind of nonlinear models has important applications in the field of telecommunications, e.g. to model uplink channels in Radio Over Fiber multiuser communication systems. The proposed technique is based on the decomposition of a tensor composed of covariances of the chip-rate sampled received signals, the transmitted signals being assumed to be Phase Shift Keying (PSK) modulated. The considered tensor-based approach allows a great flexibility on the number of antennas and the spreading factor, which is particularly desirable when identifying nonlinear systems. Two blind channel estimation algorithms are considered: the Alternating Least Squares (ALS) algorithm and a non-iterative algorithm based on Eigenvalue Decompositions (EVD). The performance of the proposed estimation algorithms is illustrated by means of computer simulations.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114379696","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641661
C. Medina, T. Vinhoza, R. Sampaio-Neto
In this paper we propose a blind adaptive channel estimator for multicarrier CDMA systems. The proposed algorithm is derived from the stochastic gradient solution for the linearly constrained minimum variance detector and it is shown to present lower computational complexity when compared to a well-known solution. It is shown through computer simulations that both the channel estimation and receiver filter achieve a slightly better performance than previously proposed methods.
{"title":"Reduced complexity blind channel estimation for adaptive constrained minimum variance receivers in MC-CDMA systems","authors":"C. Medina, T. Vinhoza, R. Sampaio-Neto","doi":"10.1109/SPAWC.2008.4641661","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641661","url":null,"abstract":"In this paper we propose a blind adaptive channel estimator for multicarrier CDMA systems. The proposed algorithm is derived from the stochastic gradient solution for the linearly constrained minimum variance detector and it is shown to present lower computational complexity when compared to a well-known solution. It is shown through computer simulations that both the channel estimation and receiver filter achieve a slightly better performance than previously proposed methods.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115764946","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641675
M. Beko, J. Xavier, V. Barroso
The non-coherent single-user multiple-input multiple-output (MIMO) channel in the low signal-to-noise ratio (SNR) regime is analyzed from the capacity point of view. We investigate the impact of channel and noise correlation on the mutual information for the on-off and Gaussian signaling schemes. The novelty is that we allow an arbitrary structure for both the channel and noise correlation matrices. Our results establish that, in the low SNR regime, mutual information is maximized when the channel correlation matrix is of rank one.
{"title":"Low SNR analysis of the non-coherent MIMO channel under arbitrary channel and noise correlation structures","authors":"M. Beko, J. Xavier, V. Barroso","doi":"10.1109/SPAWC.2008.4641675","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641675","url":null,"abstract":"The non-coherent single-user multiple-input multiple-output (MIMO) channel in the low signal-to-noise ratio (SNR) regime is analyzed from the capacity point of view. We investigate the impact of channel and noise correlation on the mutual information for the on-off and Gaussian signaling schemes. The novelty is that we allow an arbitrary structure for both the channel and noise correlation matrices. Our results establish that, in the low SNR regime, mutual information is maximized when the channel correlation matrix is of rank one.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123534102","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641616
Sami Akın, M. C. Gursoy
In this paper, pilot-assisted transmission over time-selective flat fading channels is studied. It is assumed that noncausal and causal Wiener filters are employed at the receiver to perform channel estimation with the aid of training symbols sent periodically by the transmitter. For both filters, the variances of estimate errors are obtained from the Doppler power spectrum of the channel. Subsequently, achievable rate expressions are provided. The training period, and data and training power allocations are jointly optimized by maximizing the achievable rate expressions. Numerical results are obtained by modeling the fading as a Gauss-Markov process. The achievable rates of causal and noncausal filtering approaches are compared. For the particular ranges of parameters considered in the paper, the performance loss incurred by using a causal filter as opposed to a noncausal filter is shown to be small. The impact of aliasing that occurs in the undersampled version of the channel Doppler spectrum due to fast fading is analyzed. Finally, energy-per-bit requirements are investigated in the presence of noncausal and causal Wiener filters.
{"title":"Pilot-symbol-assisted communications with noncausal and causal Wiener filters","authors":"Sami Akın, M. C. Gursoy","doi":"10.1109/SPAWC.2008.4641616","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641616","url":null,"abstract":"In this paper, pilot-assisted transmission over time-selective flat fading channels is studied. It is assumed that noncausal and causal Wiener filters are employed at the receiver to perform channel estimation with the aid of training symbols sent periodically by the transmitter. For both filters, the variances of estimate errors are obtained from the Doppler power spectrum of the channel. Subsequently, achievable rate expressions are provided. The training period, and data and training power allocations are jointly optimized by maximizing the achievable rate expressions. Numerical results are obtained by modeling the fading as a Gauss-Markov process. The achievable rates of causal and noncausal filtering approaches are compared. For the particular ranges of parameters considered in the paper, the performance loss incurred by using a causal filter as opposed to a noncausal filter is shown to be small. The impact of aliasing that occurs in the undersampled version of the channel Doppler spectrum due to fast fading is analyzed. Finally, energy-per-bit requirements are investigated in the presence of noncausal and causal Wiener filters.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122118522","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641630
A. del Coso, C. Ibars
This paper considers the Gaussian multiple access channel (MAC) assisted by N parallel relays. For the channel, the rate region with decode-and-forward is derived, considering both full-duplex and half-duplex relaying. The asymptotic sum-rate of the channel, under Rayleigh-distributed fading, is also presented. We prove that the sum-rate of the MAC with D&F relays converges almost surely to the sum-rate without relays. Hence, at the asymptote, multiuser diversity makes D&F relaying useless. Nevertheless, is also shown here that for finite number of users, the sum-rate converges to a strictly increasing function of the number of relays.
{"title":"Multi-access channels with multiple decode-and-forward relays: Rate region and asymptotic sum-rate","authors":"A. del Coso, C. Ibars","doi":"10.1109/SPAWC.2008.4641630","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641630","url":null,"abstract":"This paper considers the Gaussian multiple access channel (MAC) assisted by N parallel relays. For the channel, the rate region with decode-and-forward is derived, considering both full-duplex and half-duplex relaying. The asymptotic sum-rate of the channel, under Rayleigh-distributed fading, is also presented. We prove that the sum-rate of the MAC with D&F relays converges almost surely to the sum-rate without relays. Hence, at the asymptote, multiuser diversity makes D&F relaying useless. Nevertheless, is also shown here that for finite number of users, the sum-rate converges to a strictly increasing function of the number of relays.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129283361","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641601
J. Potman, R. Schiphorst, C. Slump
This paper describes a novel on-demand receive filter in an UMTS terminal. The receive filter is the first function after the Analog-to-Digital converter and is for that reason one of the most computation intensive parts in a receiver. The proposed filter architecture measures the out-of-band interference and calculates the required attenuation, which is used to select the appropriate filter. To assess the advantages of this on-demand receive filter, we have carried out field strength measurements in the UMTS FDD downlink band (2.1 GHz). These measurements were carried out in Amsterdam, a dense urban area with 5 active UMTS operators. Our measurement results show that in a live network configuration there is almost no out-of-band interference. Moreover, an on-demand filter would save in this case more than 68% power compared to a fixed conventional receive filter.
{"title":"On-demand receive filtering in an UMTS terminal","authors":"J. Potman, R. Schiphorst, C. Slump","doi":"10.1109/SPAWC.2008.4641601","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641601","url":null,"abstract":"This paper describes a novel on-demand receive filter in an UMTS terminal. The receive filter is the first function after the Analog-to-Digital converter and is for that reason one of the most computation intensive parts in a receiver. The proposed filter architecture measures the out-of-band interference and calculates the required attenuation, which is used to select the appropriate filter. To assess the advantages of this on-demand receive filter, we have carried out field strength measurements in the UMTS FDD downlink band (2.1 GHz). These measurements were carried out in Amsterdam, a dense urban area with 5 active UMTS operators. Our measurement results show that in a live network configuration there is almost no out-of-band interference. Moreover, an on-demand filter would save in this case more than 68% power compared to a fixed conventional receive filter.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129638250","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641612
A. Aíssa-El-Bey, K. Abed-Meraim
In this paper, we are interested in blind identification of single-input multiple-output (SIMO) systems. Using the sparsity property of impulse response, we propose an iterative method which minimizes a cost function based on the lscrp norm. This norm is considered as a good sparsity measure. The simulations show that the proposed method outperforms existing techniques in terms of estimation error and robustness to channel order overestimation.
{"title":"Blind SIMO channel identification using a sparsity criterion","authors":"A. Aíssa-El-Bey, K. Abed-Meraim","doi":"10.1109/SPAWC.2008.4641612","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641612","url":null,"abstract":"In this paper, we are interested in blind identification of single-input multiple-output (SIMO) systems. Using the sparsity property of impulse response, we propose an iterative method which minimizes a cost function based on the lscrp norm. This norm is considered as a good sparsity measure. The simulations show that the proposed method outperforms existing techniques in terms of estimation error and robustness to channel order overestimation.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122434800","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641603
J. Kolodziej, O. J. Tobias, R. Seara, D. Morgan
The purpose of this paper is to report on an unsuitable behavior of the constrained stochastic gradient (CSG) algorithm for adaptive beamforming in the combination of two events: one or more interference angles-of-arrival are close to the signal angle-of-arrival and the angle spreads of the involved signals are small. In this situation, the CSG algorithm stresses the co-channel interference minimization more than the maximization of the power radiated to the in-cell mobile terminal. We term this phenomenon unbalanced behavior and provide an analytical study to explain it.
{"title":"On the constrained stochastic gradient algorithm behavior in wireless communication networks","authors":"J. Kolodziej, O. J. Tobias, R. Seara, D. Morgan","doi":"10.1109/SPAWC.2008.4641603","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641603","url":null,"abstract":"The purpose of this paper is to report on an unsuitable behavior of the constrained stochastic gradient (CSG) algorithm for adaptive beamforming in the combination of two events: one or more interference angles-of-arrival are close to the signal angle-of-arrival and the angle spreads of the involved signals are small. In this situation, the CSG algorithm stresses the co-channel interference minimization more than the maximization of the power radiated to the in-cell mobile terminal. We term this phenomenon unbalanced behavior and provide an analytical study to explain it.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"661 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120877900","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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