Pub Date : 2008-10-26DOI: 10.1109/ACSSC.2008.5074510
A. Tisserand
This article reports the first results on fast and accurate power evaluation in arithmetic operators. The proposed method uses two steps: 1) accurate useful activity evaluation, 2) fast glitching activity estimation. The first step is based on circuit emulation using FPGA. Activity counters are inserted into the low-level description of the evaluated operator. The modified description is synthesized and downloaded into the FPGA. The operator activity behavior is emulated on the FPGA using large test vectors. The useful activity values accumulated in the FPGA are transferred to the computer. The second step uses the formal model we proposed in for glitching activity estimation. The complete method is demonstrated on basic multipliers.
{"title":"Fast and accurate activity evaluation in multipliers","authors":"A. Tisserand","doi":"10.1109/ACSSC.2008.5074510","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074510","url":null,"abstract":"This article reports the first results on fast and accurate power evaluation in arithmetic operators. The proposed method uses two steps: 1) accurate useful activity evaluation, 2) fast glitching activity estimation. The first step is based on circuit emulation using FPGA. Activity counters are inserted into the low-level description of the evaluated operator. The modified description is synthesized and downloaded into the FPGA. The operator activity behavior is emulated on the FPGA using large test vectors. The useful activity values accumulated in the FPGA are transferred to the computer. The second step uses the formal model we proposed in for glitching activity estimation. The complete method is demonstrated on basic multipliers.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115150529","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074366
V. Annapureddy, V. Veeravalli, S. Vishwanath, Austin sriram
Treating interference as noise has recently been shown to be sum capacity achieving for the two-user single-input single-output (SISO) Gaussian interference channel in a low interference regime. In this paper, we characterize the low interference regime for the multiple-input single-output (MISO) Gaussian interference channel. We also provide partial results for the general multiple-input multiple-output (MIMO) Gaussian interference channel.
{"title":"On the sum capacity of MIMO interference channel in the low interference regime","authors":"V. Annapureddy, V. Veeravalli, S. Vishwanath, Austin sriram","doi":"10.1109/ACSSC.2008.5074366","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074366","url":null,"abstract":"Treating interference as noise has recently been shown to be sum capacity achieving for the two-user single-input single-output (SISO) Gaussian interference channel in a low interference regime. In this paper, we characterize the low interference regime for the multiple-input single-output (MISO) Gaussian interference channel. We also provide partial results for the general multiple-input multiple-output (MIMO) Gaussian interference channel.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115638874","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074573
M. Salman Asif, J. Romberg
The central framework for signal recovery in compressive sensing is lscr1 norm minimization. In recent years, tremendous progress has been made on algorithms, typically based on some kind of gradient descent or Newton iterations, for performing lscr1 norm minimization. These algorithms, however, are for the most part ldquostaticrdquo: they focus on finding the solution for a fixed set of measurements. In this paper, we will present a method for quickly updating the solution to some lscr1 norm minimization problems as new measurements are added. The result is an ldquolscr1 filterrdquo and can be implemented using standard techniques from numerical linear algebra. Our proposed scheme is homotopy based where we add new measurements in the system and instead of solving updated problem directly, we solve a series of simple (easy to solve) intermediate problems which lead to the desired solution.
{"title":"Streaming measurements in compressive sensing: ℓ1 filtering","authors":"M. Salman Asif, J. Romberg","doi":"10.1109/ACSSC.2008.5074573","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074573","url":null,"abstract":"The central framework for signal recovery in compressive sensing is lscr1 norm minimization. In recent years, tremendous progress has been made on algorithms, typically based on some kind of gradient descent or Newton iterations, for performing lscr1 norm minimization. These algorithms, however, are for the most part ldquostaticrdquo: they focus on finding the solution for a fixed set of measurements. In this paper, we will present a method for quickly updating the solution to some lscr1 norm minimization problems as new measurements are added. The result is an ldquolscr1 filterrdquo and can be implemented using standard techniques from numerical linear algebra. Our proposed scheme is homotopy based where we add new measurements in the system and instead of solving updated problem directly, we solve a series of simple (easy to solve) intermediate problems which lead to the desired solution.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124407044","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074369
Keqin Liu, Qing Zhao
We consider an opportunistic communication system consisting of multiple independent channels with time-varying states. We formulate the problem of optimal sequential channel selection as a restless multi-armed bandit process, for which a powerful policy-Whittle's index policy-can be implemented based on the indexability of the system. We obtain Whittle's index in closed-form under the average reward criterion, which leads to the direct implementation of Whittle's index policy. To evaluate the performance of Whittle's index policy, we provide simple algorithms to calculate an upper bound of the optimal performance. The tightness of the upper bound and the near-optimal performance of Whittle's index policy are illustrated with simulation examples. When channels are stochastically identical, we show that Whittle's index policy is equivalent to the myopic policy, which has a simple and robust structure. Based on this structure, we establish the approximation factors of the performance of Whittle's index policy. Furthermore, we show that Whittle's index policy is optimal under certain conditions.
{"title":"Channel probing for opportunistic access with multi-channel sensing","authors":"Keqin Liu, Qing Zhao","doi":"10.1109/ACSSC.2008.5074369","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074369","url":null,"abstract":"We consider an opportunistic communication system consisting of multiple independent channels with time-varying states. We formulate the problem of optimal sequential channel selection as a restless multi-armed bandit process, for which a powerful policy-Whittle's index policy-can be implemented based on the indexability of the system. We obtain Whittle's index in closed-form under the average reward criterion, which leads to the direct implementation of Whittle's index policy. To evaluate the performance of Whittle's index policy, we provide simple algorithms to calculate an upper bound of the optimal performance. The tightness of the upper bound and the near-optimal performance of Whittle's index policy are illustrated with simulation examples. When channels are stochastically identical, we show that Whittle's index policy is equivalent to the myopic policy, which has a simple and robust structure. Based on this structure, we establish the approximation factors of the performance of Whittle's index policy. Furthermore, we show that Whittle's index policy is optimal under certain conditions.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124251578","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074521
Emanuël Habets
In speech communication systems the received microphone signals are degraded by room reverberation and ambient noise. Reverberant speech can be separated into two components, viz. an early speech component and a late reverberant speech component. In this paper a multichannel dereverberation algorithm is proposed to suppress late reverberation. Specifically, we employ a minimum variance distortionless beamformer and a single-channel MMSE estimator, which operates on the beamformer's output signal. The so-called late reverberant spectral variance (LRSV) required by the MMSE estimator can be estimated using i) the beamformer's output signal or ii) the received microphone signals. In this contribution we investigate both approaches and show how a priori knowledge of the reverberant sound field can be exploited to improve the LRSV estimation. Advantages and disadvantages of the LRSV estimators are discussed, and experimental results using simulated reverberant speech are presented.
{"title":"Towards multi-microphone speech dereverberation using spectral enhancement and statistical reverberation models","authors":"Emanuël Habets","doi":"10.1109/ACSSC.2008.5074521","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074521","url":null,"abstract":"In speech communication systems the received microphone signals are degraded by room reverberation and ambient noise. Reverberant speech can be separated into two components, viz. an early speech component and a late reverberant speech component. In this paper a multichannel dereverberation algorithm is proposed to suppress late reverberation. Specifically, we employ a minimum variance distortionless beamformer and a single-channel MMSE estimator, which operates on the beamformer's output signal. The so-called late reverberant spectral variance (LRSV) required by the MMSE estimator can be estimated using i) the beamformer's output signal or ii) the received microphone signals. In this contribution we investigate both approaches and show how a priori knowledge of the reverberant sound field can be exploited to improve the LRSV estimation. Advantages and disadvantages of the LRSV estimators are discussed, and experimental results using simulated reverberant speech are presented.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116901617","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074604
M. Spangenberg, V. Calmettes, O. Julien, J. Tourneret, G. Duchâteau
This paper studies an urban navigation filter for land vehicles. Typical urban-canyon phenomena as multipath and GPS outages seriously degrade positioning performance. To deal with these scenarios a hybrid navigation system using GPS and dead-reckoning sensors is presented. This navigation system is complemented by a two-step detection procedure that classifies outliers according to their associated source of error. Two different situations will be considered in the presence of multipath. These situations correspond to the presence or absence of line of sight for the different GPS satellites. Therefore, two kinds of errors are potentially ldquocorruptingrdquo the pseudo-ranges, modeled as variance changes or mean value jumps in noise measurements. An original multiple model approach is proposed to detect, identify and correct these errors and provide a final consistent solution.
{"title":"Detection of variance changes and mean value jumps in measurement noise for multipath mitigation in urban navigation","authors":"M. Spangenberg, V. Calmettes, O. Julien, J. Tourneret, G. Duchâteau","doi":"10.1109/ACSSC.2008.5074604","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074604","url":null,"abstract":"This paper studies an urban navigation filter for land vehicles. Typical urban-canyon phenomena as multipath and GPS outages seriously degrade positioning performance. To deal with these scenarios a hybrid navigation system using GPS and dead-reckoning sensors is presented. This navigation system is complemented by a two-step detection procedure that classifies outliers according to their associated source of error. Two different situations will be considered in the presence of multipath. These situations correspond to the presence or absence of line of sight for the different GPS satellites. Therefore, two kinds of errors are potentially ldquocorruptingrdquo the pseudo-ranges, modeled as variance changes or mean value jumps in noise measurements. An original multiple model approach is proposed to detect, identify and correct these errors and provide a final consistent solution.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116953093","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074784
Man-On Pun, K. Kim, R. Iltis, H. V. Poor
Opportunistic scheduling and beamforming schemes have been proposed previously by the authors for reduced-feedback MIMO-OFDMA downlink systems where the MIMO channel of each subcarrier is decomposed into layered spatial subchannels. It has been demonstrated that significant feedback reduction can be achieved by returning information about only one beamforming matrix (BFM) for all subcarriers from each MT, compared to one BFM for each subcarrier in the conventional schemes. However, since the previously proposed channel decomposition was derived based on singular value decomposition, the resulting system performance is impaired by the subchannels associated with the smallest singular values. To circumvent this obstacle, this work proposes improved opportunistic scheduling and beamforming schemes based on geometric mean decomposition-based channel decomposition. In addition to the inherent advantage in reduced feedback, the proposed schemes can achieve improved system performance by decomposing the MIMO channels into spatial subchannels with more evenly distributed channel gains. Numerical results confirm the effectiveness of the proposed opportunistic scheduling and beamforming schemes.
{"title":"Reduced-feedback opportunistic scheduling and beamforming with GMD for MIMO-OFDMA","authors":"Man-On Pun, K. Kim, R. Iltis, H. V. Poor","doi":"10.1109/ACSSC.2008.5074784","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074784","url":null,"abstract":"Opportunistic scheduling and beamforming schemes have been proposed previously by the authors for reduced-feedback MIMO-OFDMA downlink systems where the MIMO channel of each subcarrier is decomposed into layered spatial subchannels. It has been demonstrated that significant feedback reduction can be achieved by returning information about only one beamforming matrix (BFM) for all subcarriers from each MT, compared to one BFM for each subcarrier in the conventional schemes. However, since the previously proposed channel decomposition was derived based on singular value decomposition, the resulting system performance is impaired by the subchannels associated with the smallest singular values. To circumvent this obstacle, this work proposes improved opportunistic scheduling and beamforming schemes based on geometric mean decomposition-based channel decomposition. In addition to the inherent advantage in reduced feedback, the proposed schemes can achieve improved system performance by decomposing the MIMO channels into spatial subchannels with more evenly distributed channel gains. Numerical results confirm the effectiveness of the proposed opportunistic scheduling and beamforming schemes.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127169100","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074394
C. Berger, Shengli Zhou, P. Willett, B. Demissie, J. Heckenbach
In passive radar, two main challenges are: mitigating the direct blast, since the illuminators broadcast continuously, and achieving a large enough integration gain to detect targets. While the first has to be solved in part in the analog part of the processing chain, due to the huge difference of signal strength between the direct blast and weak target reflections, the second is about combining enough signal efficiently, while not sacrificing too much performance. When combining this setup with digital multicarrier waveforms like orthogonal frequency division multiplex (OFDM) in digital audio/video broadcast (DAB/DVB), this problem can be seen to be a version of multiple-input multiple-output (MIMO) radar. We start with an existing approach, based on efficient fast Fourier transform (FFT) operation to detect target signatures, and show how this approach is related to a standard matched filter approach based on a piece-wise constant approximation of the phase rotation caused by Doppler shift. We then suggest two more applicable algorithms, one based on subspace processing and one based on sparse estimation. We compare these various approaches based on a detailed simulation scenario with two closing targets and experimental data recorded from a DAB network in Germany.
{"title":"Compressed sensing for OFDM/MIMO radar","authors":"C. Berger, Shengli Zhou, P. Willett, B. Demissie, J. Heckenbach","doi":"10.1109/ACSSC.2008.5074394","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074394","url":null,"abstract":"In passive radar, two main challenges are: mitigating the direct blast, since the illuminators broadcast continuously, and achieving a large enough integration gain to detect targets. While the first has to be solved in part in the analog part of the processing chain, due to the huge difference of signal strength between the direct blast and weak target reflections, the second is about combining enough signal efficiently, while not sacrificing too much performance. When combining this setup with digital multicarrier waveforms like orthogonal frequency division multiplex (OFDM) in digital audio/video broadcast (DAB/DVB), this problem can be seen to be a version of multiple-input multiple-output (MIMO) radar. We start with an existing approach, based on efficient fast Fourier transform (FFT) operation to detect target signatures, and show how this approach is related to a standard matched filter approach based on a piece-wise constant approximation of the phase rotation caused by Doppler shift. We then suggest two more applicable algorithms, one based on subspace processing and one based on sparse estimation. We compare these various approaches based on a detailed simulation scenario with two closing targets and experimental data recorded from a DAB network in Germany.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125793351","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074696
M. Ferrara
{"title":"Session TP7b: Performance prediction and analysis for signal and image processing systems","authors":"M. Ferrara","doi":"10.1109/ACSSC.2008.5074696","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074696","url":null,"abstract":"","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123690325","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 : 2008-10-01DOI: 10.1109/ACSSC.2008.5074739
O. Gustafsson, K. Johansson
When hardware for implementing elementary functions is discussed it is often stated that for ldquosmall enoughrdquo tables it is possible to just synthesize the HDL description to standard cells. In this work we investigate this fact and show that the resulting cell area primarily depends on the smallest of the number of input and output bits, while the contribution of the larger of the two bit-widths is significantly smaller.
{"title":"An empirical study on standard cell synthesis of elementary function lookup tables","authors":"O. Gustafsson, K. Johansson","doi":"10.1109/ACSSC.2008.5074739","DOIUrl":"https://doi.org/10.1109/ACSSC.2008.5074739","url":null,"abstract":"When hardware for implementing elementary functions is discussed it is often stated that for ldquosmall enoughrdquo tables it is possible to just synthesize the HDL description to standard cells. In this work we investigate this fact and show that the resulting cell area primarily depends on the smallest of the number of input and output bits, while the contribution of the larger of the two bit-widths is significantly smaller.","PeriodicalId":416114,"journal":{"name":"2008 42nd Asilomar Conference on Signals, Systems and Computers","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123702166","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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