Pub Date : 1900-01-01DOI: 10.1109/ACSSC.2005.1599825
M. Vu, A. Paulraj
Transmit channel side information (CSIT) can improve performance of MIMO wireless systems by means of precoding. More complete and reliable CSIT provides more precoding gain. Instantaneous channel measurements provide the most potential gain, but suffer from delay-induced error due to channel temporal variation. Statistical channel knowledge provides less gain, but is reliable. In this paper, we propose a framework combining a possibly outdated channel measurement with the channel statistics - the mean and the covariance - to create a dynamic CSIT form, as a function of a correlation factor between the measurement and the current channel. The CSIT consists of an estimate of the current channel and the associated estimation error covariance, which function effectively as the channel mean and covariance. We apply a precoder design exploiting these channel statistics to illustrate the achievable gain and the robustness of the new CSIT framework
{"title":"A robust transmit CSI framework with applications in MIMO wireless precoding","authors":"M. Vu, A. Paulraj","doi":"10.1109/ACSSC.2005.1599825","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599825","url":null,"abstract":"Transmit channel side information (CSIT) can improve performance of MIMO wireless systems by means of precoding. More complete and reliable CSIT provides more precoding gain. Instantaneous channel measurements provide the most potential gain, but suffer from delay-induced error due to channel temporal variation. Statistical channel knowledge provides less gain, but is reliable. In this paper, we propose a framework combining a possibly outdated channel measurement with the channel statistics - the mean and the covariance - to create a dynamic CSIT form, as a function of a correlation factor between the measurement and the current channel. The CSIT consists of an estimate of the current channel and the associated estimation error covariance, which function effectively as the channel mean and covariance. We apply a precoder design exploiting these channel statistics to illustrate the achievable gain and the robustness of the new CSIT framework","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126106968","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599886
S. Agaian, D. Akopian, O. Caglayan, S. D'Souza
This paper presents a lossless adaptive digital audio steganographic technique based on reversible two and higher dimensional integer transform. The adaptive technique is used to choose the best blocks for embedding perceptually inaudible stego information, and to select the best block sizes to maximize the number of blocks/capacity. The stego information is embedded in the integer domain by bit manipulation. In addition, we intro- duce a capacity measure to select audio carriers that in- troduce minimum distortion after embedding. The above technique is also applicable to compression based audio formats, such as MPEG audio layer-3 (mp3).
{"title":"Lossless Adaptive Digital Audio Steganography","authors":"S. Agaian, D. Akopian, O. Caglayan, S. D'Souza","doi":"10.1109/ACSSC.2005.1599886","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599886","url":null,"abstract":"This paper presents a lossless adaptive digital audio steganographic technique based on reversible two and higher dimensional integer transform. The adaptive technique is used to choose the best blocks for embedding perceptually inaudible stego information, and to select the best block sizes to maximize the number of blocks/capacity. The stego information is embedded in the integer domain by bit manipulation. In addition, we intro- duce a capacity measure to select audio carriers that in- troduce minimum distortion after embedding. The above technique is also applicable to compression based audio formats, such as MPEG audio layer-3 (mp3).","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114195769","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599733
C. Meesookho, S. Narayanan
Target localization is a key application in the sensor network context. Of the various conventional methods can be applied, and have been proposed, the range difference (RD) based method is attractive due to improved accuracy and ease of implementation it affords. While the basic concepts of the RD based method can be adapted to the case of sensor networks, the data acquisition and aggregation procedures need to be formulated and characterized subject to the energy constraint. The challenge is to design an efficient algorithm that is economical and still accurate. In this paper, based on range difference localization method, we propose a distributed algorithm which allows the time delay estimation to be carried out at each participating sensor. The acquired data is fused using a sequential least squares scheme which enables the appropriate sensor selection based on the current estimate. The results distributed localization produces smaller error and consumes less energy than the centralized method. The advantage of distributed localization in terms of the accuracy becomes more conspicuous when the number of participating sensors is small while the energy saving increases when the number of participating sensors to decreasing target signal energy and the instantaneous error from the sequence of estimates can be approximated and used to reconcile the cost and the system performance
{"title":"Distributed Range Difference Based Target Localization in Sensor Network","authors":"C. Meesookho, S. Narayanan","doi":"10.1109/ACSSC.2005.1599733","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599733","url":null,"abstract":"Target localization is a key application in the sensor network context. Of the various conventional methods can be applied, and have been proposed, the range difference (RD) based method is attractive due to improved accuracy and ease of implementation it affords. While the basic concepts of the RD based method can be adapted to the case of sensor networks, the data acquisition and aggregation procedures need to be formulated and characterized subject to the energy constraint. The challenge is to design an efficient algorithm that is economical and still accurate. In this paper, based on range difference localization method, we propose a distributed algorithm which allows the time delay estimation to be carried out at each participating sensor. The acquired data is fused using a sequential least squares scheme which enables the appropriate sensor selection based on the current estimate. The results distributed localization produces smaller error and consumes less energy than the centralized method. The advantage of distributed localization in terms of the accuracy becomes more conspicuous when the number of participating sensors is small while the energy saving increases when the number of participating sensors to decreasing target signal energy and the instantaneous error from the sequence of estimates can be approximated and used to reconcile the cost and the system performance","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"411 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116243600","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599887
K. Karadimou, A. Mouchtaris, P. Tsakalides
In this paper we propose a source/filter model for achieving low bitrate transmission of multichannel audio signals, in which the filter part corresponds to the specifics of each microphone information while the source part contains mostly the interchannel similarities. Using the appropriate filter for each channel and the source part of only one of the microphone signals, we can resynthesize a high quality approximation of each channel; thus, the filter part of each channel need only be encoded. Low datarates can be achieved in the order of few KBits/sec/channel focusing on applications such as remote mixing or distributed musicians collaboration.
{"title":"Multichannel Audio Modeling and Coding Using a Multiband Source/Filter Model","authors":"K. Karadimou, A. Mouchtaris, P. Tsakalides","doi":"10.1109/ACSSC.2005.1599887","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599887","url":null,"abstract":"In this paper we propose a source/filter model for achieving low bitrate transmission of multichannel audio signals, in which the filter part corresponds to the specifics of each microphone information while the source part contains mostly the interchannel similarities. Using the appropriate filter for each channel and the source part of only one of the microphone signals, we can resynthesize a high quality approximation of each channel; thus, the filter part of each channel need only be encoded. Low datarates can be achieved in the order of few KBits/sec/channel focusing on applications such as remote mixing or distributed musicians collaboration.","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115832217","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599930
R.D. Weaver
This paper questions the appropriateness of the mean squared error (MSE) as dominant performance metric for the maximum-likelihood delay estimator. The departure of the MSE from the Crambound is seen as an incidental effect, whereas knowledge of the frequencies of nominal estimates versus outliers leads to better statistics. Simulations are used to evaluate an alternative scheme for robust acquisition of signal delay, based upon binning statistics. This scheme converges on the correct estimate at signal-to-noise ratios that are well below the MSE threshold and into the "no information" region. I. INTRODUCTION
{"title":"No Information? Delay Estimation Below the Threshold SNR","authors":"R.D. Weaver","doi":"10.1109/ACSSC.2005.1599930","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599930","url":null,"abstract":"This paper questions the appropriateness of the mean squared error (MSE) as dominant performance metric for the maximum-likelihood delay estimator. The departure of the MSE from the Crambound is seen as an incidental effect, whereas knowledge of the frequencies of nominal estimates versus outliers leads to better statistics. Simulations are used to evaluate an alternative scheme for robust acquisition of signal delay, based upon binning statistics. This scheme converges on the correct estimate at signal-to-noise ratios that are well below the MSE threshold and into the \"no information\" region. I. INTRODUCTION","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125630593","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599722
Liuqing Yang, Jian Li, Yi Jiang
Wireless networks, while evolving to provide an unprecedented variety of services, often encounter heterogeneous nodes. In the mean time, ultra-wideband (UWB) link emerges as a promising physical layer candidate for a wide range of wireless networks. In addition to the potential of very high data rate, the ultra-wide bandwidth also provides enhanced flexibility for transceiver designs with variable complexity, which is particularly suitable for networks with heterogeneous nodes. However, to establish physical communication links between nodes with distinct complexity requirements, asymmetric UWB transceivers need to be designed. Towards this objective, we utilize their similarity with multi-input multi-output (MIMO) systems and deploy the geometric mean decomposition (GMD) approach to achieve optimally in terms of both channel throughput and bit error rate (BER). Analysis and simulations corroborate the effectiveness of our transceiver designs
{"title":"Capacity-approaching transceiver design for asymmetric UWB links","authors":"Liuqing Yang, Jian Li, Yi Jiang","doi":"10.1109/ACSSC.2005.1599722","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599722","url":null,"abstract":"Wireless networks, while evolving to provide an unprecedented variety of services, often encounter heterogeneous nodes. In the mean time, ultra-wideband (UWB) link emerges as a promising physical layer candidate for a wide range of wireless networks. In addition to the potential of very high data rate, the ultra-wide bandwidth also provides enhanced flexibility for transceiver designs with variable complexity, which is particularly suitable for networks with heterogeneous nodes. However, to establish physical communication links between nodes with distinct complexity requirements, asymmetric UWB transceivers need to be designed. Towards this objective, we utilize their similarity with multi-input multi-output (MIMO) systems and deploy the geometric mean decomposition (GMD) approach to achieve optimally in terms of both channel throughput and bit error rate (BER). Analysis and simulations corroborate the effectiveness of our transceiver designs","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131625668","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599699
A. Jagannathan, E. Miller
A new mesh decimation algorithm is proposed to address the problem of obtaining shape-preserving coarse approximations of a highly detailed 3D surface mesh. The input mesh is segmented into multiple, disjoint sub-meshes to facilitate decimation. Given a sub-mesh, various shape clusters are identified and the vertices in those clusters arc labeled as boundary or interior. Shape is preserved by considering only similar-labeled vertex pairs as candidates for a potential merge. Sub-mesh decimation is realized by merging a vertex pair that minimizes the proposed graph energy based cost function. Results demonstrate the efficiency and efficacy of the approach
{"title":"Shape-preserving mesh decimation within a graph-theoretic framework","authors":"A. Jagannathan, E. Miller","doi":"10.1109/ACSSC.2005.1599699","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599699","url":null,"abstract":"A new mesh decimation algorithm is proposed to address the problem of obtaining shape-preserving coarse approximations of a highly detailed 3D surface mesh. The input mesh is segmented into multiple, disjoint sub-meshes to facilitate decimation. Given a sub-mesh, various shape clusters are identified and the vertices in those clusters arc labeled as boundary or interior. Shape is preserved by considering only similar-labeled vertex pairs as candidates for a potential merge. Sub-mesh decimation is realized by merging a vertex pair that minimizes the proposed graph energy based cost function. Results demonstrate the efficiency and efficacy of the approach","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128114814","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599719
T. Svantesson, B. Rao
This paper provides n framework for deriving MIMO capacity bounds that takes channel estimation error into account by using the Cramer-Rao bound (CRB). Combining the CRB with capacity analysis allows for studies of the trade-off between estimation performance and throughput. The framework is used to investigate the impact of the spatio-temporal structure found in practical channel sounding experiments. Numerical evaluations indicate that higher capacities are possible and the optimum number of training symbols and transmit antennas are different when exploiting the structure in the channel compared to previous unstructured approaches
{"title":"A Framework for MIMO Capacity Bounds Based on the Cramer-Rao Bound on the Channel Estimation Error","authors":"T. Svantesson, B. Rao","doi":"10.1109/ACSSC.2005.1599719","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599719","url":null,"abstract":"This paper provides n framework for deriving MIMO capacity bounds that takes channel estimation error into account by using the Cramer-Rao bound (CRB). Combining the CRB with capacity analysis allows for studies of the trade-off between estimation performance and throughput. The framework is used to investigate the impact of the spatio-temporal structure found in practical channel sounding experiments. Numerical evaluations indicate that higher capacities are possible and the optimum number of training symbols and transmit antennas are different when exploiting the structure in the channel compared to previous unstructured approaches","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133536480","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599860
H. Dehghan, C. Weber
An analytic model of the Cat-5 subclass cable structure, as described in TIA cabling standards (2001), is developed and derived and a simple FIR filter model based on physical measurements is found which accurately represents the developed model. Taking advantage of the properties of the cable impulse response, a new equalizer structure (dubbed aided decision feedback equalizer - ADFE) is proposed that is a classical decision feedback equalizers (DFE) with a fixed infinite impulse response (IIR) in the feedback loop. An algorithm is given for training the new equalizer and it is shown that the proposed IIR filter reduces to a single pole filter if the feedback is chosen to be sufficiently long. The new equalizer is shown to have significantly better performance than the conventional DFE both in terms of bit error rate (BER) and signal to noise ratio (SNR) with reduced hardware complexity
{"title":"Aided Decision Feedback Equalization for Wired Communication","authors":"H. Dehghan, C. Weber","doi":"10.1109/ACSSC.2005.1599860","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599860","url":null,"abstract":"An analytic model of the Cat-5 subclass cable structure, as described in TIA cabling standards (2001), is developed and derived and a simple FIR filter model based on physical measurements is found which accurately represents the developed model. Taking advantage of the properties of the cable impulse response, a new equalizer structure (dubbed aided decision feedback equalizer - ADFE) is proposed that is a classical decision feedback equalizers (DFE) with a fixed infinite impulse response (IIR) in the feedback loop. An algorithm is given for training the new equalizer and it is shown that the proposed IIR filter reduces to a single pole filter if the feedback is chosen to be sufficiently long. The new equalizer is shown to have significantly better performance than the conventional DFE both in terms of bit error rate (BER) and signal to noise ratio (SNR) with reduced hardware complexity","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"5 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131776310","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 : 1900-01-01DOI: 10.1109/ACSSC.2005.1599716
Huahui Wang, Qi Ling, Tongtong Li
In this paper, a new variant of multicarrier code division multiple access (MC-CDMA) system is proposed and analyzed for time varying multipath fading channels. At the transmitter, data bits at different frequency bands are spread in the time domain and these spread chips are circularly shifted onto different frequency bands while the time lapses. As a result, the spread data chips are assigned to different frequency bands at different times. Significant performance improvement can be achieved compared to the conventional MC-CDMA system. The underlying reason is that in the proposed system, more diversities are introduced by spreading data chips both in the frequency and time domains. In the paper, the performance of the system using different combining techniques is analyzed and compared. Simulation results under different conditions arc also presented
{"title":"A New Multicarrier CDMA System Exploiting Frequency-Time Diversities","authors":"Huahui Wang, Qi Ling, Tongtong Li","doi":"10.1109/ACSSC.2005.1599716","DOIUrl":"https://doi.org/10.1109/ACSSC.2005.1599716","url":null,"abstract":"In this paper, a new variant of multicarrier code division multiple access (MC-CDMA) system is proposed and analyzed for time varying multipath fading channels. At the transmitter, data bits at different frequency bands are spread in the time domain and these spread chips are circularly shifted onto different frequency bands while the time lapses. As a result, the spread data chips are assigned to different frequency bands at different times. Significant performance improvement can be achieved compared to the conventional MC-CDMA system. The underlying reason is that in the proposed system, more diversities are introduced by spreading data chips both in the frequency and time domains. In the paper, the performance of the system using different combining techniques is analyzed and compared. Simulation results under different conditions arc also presented","PeriodicalId":326489,"journal":{"name":"Conference Record of the Thirty-Ninth Asilomar Conference onSignals, Systems and Computers, 2005.","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131865065","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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