Pub Date : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797709
Huan Xu, C. Caramanis, Shie Mannor
We consider the dimensionality-reduction problem for a contaminated data set in a very high dimensional space, i.e., the problem of finding a subspace approximation of observed data, where the number of observations is of the same magnitude as the number of variables of each observation, and the data set contains some outlying observations. We propose a High-dimension Robust Principal Component Analysis (HR-PCA) algorithm that is tractable, robust to outliers and easily kernelizable. The resulted subspace has a bounded deviation from the desired one, and achieves optimality in the limit case where the portion of outliers goes to zero.
{"title":"Robust dimensionality reduction for high-dimension data","authors":"Huan Xu, C. Caramanis, Shie Mannor","doi":"10.1109/ALLERTON.2008.4797709","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797709","url":null,"abstract":"We consider the dimensionality-reduction problem for a contaminated data set in a very high dimensional space, i.e., the problem of finding a subspace approximation of observed data, where the number of observations is of the same magnitude as the number of variables of each observation, and the data set contains some outlying observations. We propose a High-dimension Robust Principal Component Analysis (HR-PCA) algorithm that is tractable, robust to outliers and easily kernelizable. The resulted subspace has a bounded deviation from the desired one, and achieves optimality in the limit case where the portion of outliers goes to zero.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116584607","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797532
Y. Ohwatari, A. Benjebbour, J. Hagiwara, T. Ohya
For a multiuser (MU)-MIMO precoded transmission with individual constraints on the maximum power of each transmit antenna, the transmit power optimization problem is a non-linear convex optimization problem with a high level of computational complexity. In this paper, we propose three methods in order to reduce the computational complexity associated with this problem. The reductions in computational complexity achieved with the proposed methods are evaluated under the sum-rate maximization criterion assuming i.i.d Rayleigh fading MIMO channels and block diagonalization zero-forcing as a precoder.
{"title":"Reduced-complexity transmit power optimization techniques for multiuser MIMO with per-antenna power constraint","authors":"Y. Ohwatari, A. Benjebbour, J. Hagiwara, T. Ohya","doi":"10.1109/ALLERTON.2008.4797532","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797532","url":null,"abstract":"For a multiuser (MU)-MIMO precoded transmission with individual constraints on the maximum power of each transmit antenna, the transmit power optimization problem is a non-linear convex optimization problem with a high level of computational complexity. In this paper, we propose three methods in order to reduce the computational complexity associated with this problem. The reductions in computational complexity achieved with the proposed methods are evaluated under the sum-rate maximization criterion assuming i.i.d Rayleigh fading MIMO channels and block diagonalization zero-forcing as a precoder.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117291941","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}
Motivated by distributed sensor networks scenarios, we consider a problem of state estimation under communication constraints, in which a real-valued random vector needs to be reliably transmitted through a digital noisy channel. Estimations are sequentially updated by the receiver, as more and more channel outputs are observed. Assuming that no channel feedback is available at the transmitter, we study the rates at which the mean squared error of the estimation can be made to converge to zero with time. First, simple low-complexity schemes are considered, and trade-offs between performance and encoder/decoder complexity are found. Then, information-theoretic bounds on the best achievable error exponent are obtained.
{"title":"Anytime reliable transmission of real-valued information through digital noisy channels","authors":"G. Como, F. Fagnani, S. Zampieri","doi":"10.1137/09074601X","DOIUrl":"https://doi.org/10.1137/09074601X","url":null,"abstract":"Motivated by distributed sensor networks scenarios, we consider a problem of state estimation under communication constraints, in which a real-valued random vector needs to be reliably transmitted through a digital noisy channel. Estimations are sequentially updated by the receiver, as more and more channel outputs are observed. Assuming that no channel feedback is available at the transmitter, we study the rates at which the mean squared error of the estimation can be made to converge to zero with time. First, simple low-complexity schemes are considered, and trade-offs between performance and encoder/decoder complexity are found. Then, information-theoretic bounds on the best achievable error exponent are obtained.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129417256","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797550
A. Kamal, O. Al-Kofahi
This paper introduces an implementation of the network coding-based generalized 1+N protection technique presented earlier by the author in [1] to protect against single link failures. Instead of using two protection circuits for a group of connections which are to be protected together as in [1], only one protection circuit is used, which takes the form of a tree. The protection circuit carries linear combinations of the data units originally transmitted on the working circuits, and these linear combinations can be used to recover lost data due to link failures. This recovery is carried out with the assistance of one node on the protection tree, which is chosen to reduce the recovery time. Moreover, unlike the scheme in [1] which protects unidirectional connections, this scheme is used to protect bidirectional connections. This protection technique requires exactly the same amount of protection resources used by 1:N protection, and can therefore be considered as a step towards achieving optimal 1+N protection. The paper also makes a number of other contributions. It introduces an integer linear program (ILP) formulation to evaluate the cost of protection using this technique, and compares it to the cost of 1+1 protection. The comparison shows that a significant saving in cost can be achieved, while still recovering from failures within a short time.
{"title":"Toward an optimal 1+N protection strategy","authors":"A. Kamal, O. Al-Kofahi","doi":"10.1109/ALLERTON.2008.4797550","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797550","url":null,"abstract":"This paper introduces an implementation of the network coding-based generalized 1+N protection technique presented earlier by the author in [1] to protect against single link failures. Instead of using two protection circuits for a group of connections which are to be protected together as in [1], only one protection circuit is used, which takes the form of a tree. The protection circuit carries linear combinations of the data units originally transmitted on the working circuits, and these linear combinations can be used to recover lost data due to link failures. This recovery is carried out with the assistance of one node on the protection tree, which is chosen to reduce the recovery time. Moreover, unlike the scheme in [1] which protects unidirectional connections, this scheme is used to protect bidirectional connections. This protection technique requires exactly the same amount of protection resources used by 1:N protection, and can therefore be considered as a step towards achieving optimal 1+N protection. The paper also makes a number of other contributions. It introduces an integer linear program (ILP) formulation to evaluate the cost of protection using this technique, and compares it to the cost of 1+1 protection. The comparison shows that a significant saving in cost can be achieved, while still recovering from failures within a short time.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124744227","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797675
D. Klinc, J. Ha, S. McLaughlin
This paper investigates optimal puncturing and shortening distributions for nonbinary LDPC codes over the binary erasure channel (BEC). The analysis is done by means of density evolution and optimal distributions are found with differential evolution. We show that puncturing or shortening entire variable nodes results in bad performance; instead, for best performance, puncturing and shortening distributions have to be designed carefully, where generally, most variable nodes are punctured/shortened only partially. Our results indicate that properly designed punctured and shortened nonbinary LDPC codes can maintain a very small gap to capacity through a wide range of rates.
{"title":"Optimized puncturing and shortening distributions for nonbinary LDPC codes over the binary erasure channel","authors":"D. Klinc, J. Ha, S. McLaughlin","doi":"10.1109/ALLERTON.2008.4797675","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797675","url":null,"abstract":"This paper investigates optimal puncturing and shortening distributions for nonbinary LDPC codes over the binary erasure channel (BEC). The analysis is done by means of density evolution and optimal distributions are found with differential evolution. We show that puncturing or shortening entire variable nodes results in bad performance; instead, for best performance, puncturing and shortening distributions have to be designed carefully, where generally, most variable nodes are punctured/shortened only partially. Our results indicate that properly designed punctured and shortened nonbinary LDPC codes can maintain a very small gap to capacity through a wide range of rates.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129666527","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797632
Jae Won Yoo, Tie Liu, F. Xue
This paper considered, via a deterministic approach, the problem of broadcasting with receiver message side information, which arises naturally in the context of decoding-forward strategies in multiway relay network communication. An outer bound on the capacity region of the linear deterministic broadcast channel with general receiver message side information is provided and is shown to be tight when the side information configuration satisfies a certain property. As a corollary, the proposed outer bound is shown to be the capacity region of the linear deterministic broadcast channel with receiver message side information and with K les 3 users.
{"title":"Broadcasting with receiver message side information: A deterministic approach","authors":"Jae Won Yoo, Tie Liu, F. Xue","doi":"10.1109/ALLERTON.2008.4797632","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797632","url":null,"abstract":"This paper considered, via a deterministic approach, the problem of broadcasting with receiver message side information, which arises naturally in the context of decoding-forward strategies in multiway relay network communication. An outer bound on the capacity region of the linear deterministic broadcast channel with general receiver message side information is provided and is shown to be tight when the side information configuration satisfies a certain property. As a corollary, the proposed outer bound is shown to be the capacity region of the linear deterministic broadcast channel with receiver message side information and with K les 3 users.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"238 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121483249","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797579
I. Lobel, A. Ozdaglar
We consider the problem of cooperatively minimizing the sum of convex functions, where the functions represent local objective functions of the agents. We assume that each agent has information about his local function, and communicate with the other agents over a time-varying network topology. For this problem, we propose a distributed subgradient method that uses averaging algorithms for locally sharing information among the agents. In contrast to previous works that make worst-case assumptions about the connectivity of the agents (such as bounded communication intervals between nodes), we assume that links fail according to a given stochastic process. Under the assumption that the link failures are independent and identically distributed over time (possibly correlated across links), we provide convergence results and convergence rate estimates for our subgradient algorithm.
{"title":"Convergence analysis of distributed subgradient methods over random networks","authors":"I. Lobel, A. Ozdaglar","doi":"10.1109/ALLERTON.2008.4797579","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797579","url":null,"abstract":"We consider the problem of cooperatively minimizing the sum of convex functions, where the functions represent local objective functions of the agents. We assume that each agent has information about his local function, and communicate with the other agents over a time-varying network topology. For this problem, we propose a distributed subgradient method that uses averaging algorithms for locally sharing information among the agents. In contrast to previous works that make worst-case assumptions about the connectivity of the agents (such as bounded communication intervals between nodes), we assume that links fail according to a given stochastic process. Under the assumption that the link failures are independent and identically distributed over time (possibly correlated across links), we provide convergence results and convergence rate estimates for our subgradient algorithm.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131979462","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797647
R. Rajesh, V. Sharma
In this paper we address the problem of transmission of correlated sources over a fading multiple access channel (MAC). We provide sufficient conditions for transmission with given distortions. Next these conditions are specialized to a Gaussian MAC (GMAC). Transmission schemes for discrete and Gaussian sources over a fading GMAC are considered. Various power allocation strategies are also compared.
{"title":"Transmission of correlated sources over a fading multiple access channel","authors":"R. Rajesh, V. Sharma","doi":"10.1109/ALLERTON.2008.4797647","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797647","url":null,"abstract":"In this paper we address the problem of transmission of correlated sources over a fading multiple access channel (MAC). We provide sufficient conditions for transmission with given distortions. Next these conditions are specialized to a Gaussian MAC (GMAC). Transmission schemes for discrete and Gaussian sources over a fading GMAC are considered. Various power allocation strategies are also compared.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127634620","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797644
Ghadamali Bagherikaram, A. Motahari, A. Khandani
In this paper, we consider a scenario where a source node wishes to broadcast two confidential messages for two respective receivers, while a wire-tapper also receives the transmitted signal. This model is motivated by wireless communications, where individual secure messages are broadcast over open media and can be received by any illegitimate receiver. The secrecy level is measured by equivocation rate at the eavesdropper. We first study the general (non-degraded) broadcast channel with confidential messages. We present an inner bound on the secrecy capacity region for this model. The inner bound coding scheme is based on a combination of random binning and the Gelfand-Pinsker bining. This scheme matches the Marton's inner bound on the broadcast channel without confidentiality constraint. We further study the situation where the channels are degraded. For the degraded broadcast channel with confidential messages, we present the secrecy capacity region. Our achievable coding scheme is based on Cover's superposition scheme and random binning. We refer to this scheme as secret superposition scheme. In this scheme, we show that randomization in the first layer increases the secrecy rate of the second layer. This capacity region matches the capacity region of the degraded broadcast channel without security constraint. It also matches the secrecy capacity for the conventional wire-tap channel. Our converse proof is based on a combination of the converse proof of the conventional degraded broadcast channel and Csiszar lemma.
{"title":"Secure broadcasting : The secrecy rate region","authors":"Ghadamali Bagherikaram, A. Motahari, A. Khandani","doi":"10.1109/ALLERTON.2008.4797644","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797644","url":null,"abstract":"In this paper, we consider a scenario where a source node wishes to broadcast two confidential messages for two respective receivers, while a wire-tapper also receives the transmitted signal. This model is motivated by wireless communications, where individual secure messages are broadcast over open media and can be received by any illegitimate receiver. The secrecy level is measured by equivocation rate at the eavesdropper. We first study the general (non-degraded) broadcast channel with confidential messages. We present an inner bound on the secrecy capacity region for this model. The inner bound coding scheme is based on a combination of random binning and the Gelfand-Pinsker bining. This scheme matches the Marton's inner bound on the broadcast channel without confidentiality constraint. We further study the situation where the channels are degraded. For the degraded broadcast channel with confidential messages, we present the secrecy capacity region. Our achievable coding scheme is based on Cover's superposition scheme and random binning. We refer to this scheme as secret superposition scheme. In this scheme, we show that randomization in the first layer increases the secrecy rate of the second layer. This capacity region matches the capacity region of the degraded broadcast channel without security constraint. It also matches the secrecy capacity for the conventional wire-tap channel. Our converse proof is based on a combination of the converse proof of the conventional degraded broadcast channel and Csiszar lemma.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127386833","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797596
K. Hardwick, D. Goeckel, D. Towsley
Distributed beamforming in wireless ad hoc networks has the promise of greatly improving network throughput. However, unlike traditional beamforming from a fixed array, the random locations of the nodes collaborating to form the array lead to a random beam pattern. In particular, the position and size of side lobes can vary greatly and have a significant impact on the concurrent transmissions that are the source of much of the throughput gain realized from distributed beamforming. Here, we present a simple model that captures this randomness and then use the model to consider the average throughput of a large ad hoc wireless networks. Numerical results are compared to those obtained if one employs the oft-used pie-wedge approximation for a directed antenna beam, and the difference is shown to be significant in regions where the side lobe interference is non-negligible.
{"title":"Modeling distributed beamforming in wireless networks","authors":"K. Hardwick, D. Goeckel, D. Towsley","doi":"10.1109/ALLERTON.2008.4797596","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797596","url":null,"abstract":"Distributed beamforming in wireless ad hoc networks has the promise of greatly improving network throughput. However, unlike traditional beamforming from a fixed array, the random locations of the nodes collaborating to form the array lead to a random beam pattern. In particular, the position and size of side lobes can vary greatly and have a significant impact on the concurrent transmissions that are the source of much of the throughput gain realized from distributed beamforming. Here, we present a simple model that captures this randomness and then use the model to consider the average throughput of a large ad hoc wireless networks. Numerical results are compared to those obtained if one employs the oft-used pie-wedge approximation for a directed antenna beam, and the difference is shown to be significant in regions where the side lobe interference is non-negligible.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116986526","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：