Pub Date : 2016-10-12DOI: 10.23919/WIOPT.2017.7959862
J. Krolikowski, A. Giovanidis, M. Renzo
Caching of popular content on wireless nodes is recently proposed as a means to reduce congestion in the backbone of cellular networks and to improve Quality of Service. From a network point of view, the goal is to offload as many users as possible from the backbone network to the wireless caches while at the same time offering good service to cache-unrelated users. Aggressive offloading can lead to an unbalanced user association. Some wireless nodes can be overloaded by cache-related traffic while the resources of others remain underused. Given a fixed content placement, this work proposes an efficient distributed algorithm to control and balance the association of cache-related traffic among cellular cache memories. The algorithm allows the network to achieve the globally optimal solution and can be executed on base stations using a limited amount of information exchange between them. It is based on a novel algorithm we call Bucket-filling. The solution limits the cache-users per node by balancing the total load among the nodes in a fair way. The improvement compared to common user assignment policies is highlighted for single-as well as for multi-tier random networks.
{"title":"Fair distributed user-traffic association in cache equipped cellular networks","authors":"J. Krolikowski, A. Giovanidis, M. Renzo","doi":"10.23919/WIOPT.2017.7959862","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959862","url":null,"abstract":"Caching of popular content on wireless nodes is recently proposed as a means to reduce congestion in the backbone of cellular networks and to improve Quality of Service. From a network point of view, the goal is to offload as many users as possible from the backbone network to the wireless caches while at the same time offering good service to cache-unrelated users. Aggressive offloading can lead to an unbalanced user association. Some wireless nodes can be overloaded by cache-related traffic while the resources of others remain underused. Given a fixed content placement, this work proposes an efficient distributed algorithm to control and balance the association of cache-related traffic among cellular cache memories. The algorithm allows the network to achieve the globally optimal solution and can be executed on base stations using a limited amount of information exchange between them. It is based on a novel algorithm we call Bucket-filling. The solution limits the cache-users per node by balancing the total load among the nodes in a fair way. The improvement compared to common user assignment policies is highlighted for single-as well as for multi-tier random networks.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"28 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2016-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73447056","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 : 2012-05-14DOI: 10.1109/CISS.2012.6310763
Javad Ghaderiy, Sem Borstz, Phil Whitingz
Backlog-based wireless access schemes are simple and inherently distributed, yet provide a striking capability to match the optimal throughput performance of centralized scheduling mechanisms in a wide range of scenarios. Unfortunately, the type of activation rules for which throughput optimality has been established, may result in excessive backlogs and delays. The use of more aggressive/persistent access schemes than these can improve the delay performance, but does not offer any universal maximum-stability guarantees. Motivated by the above issues, we use fluid limits to explore the (in)stability properties of backlog-based random-access algorithms. Such fluid limits have varying qualitative properties, dependent on the specific scenario, ranging from ones with smooth deterministic features, to others which exhibit random oscillatory characteristics. It turns out that more aggressive access schemes continue to provide maximum stability in some networks, e.g. complete interference graphs. As we show however, in other topologies such schemes can drive the system into inefficient states and thus cause instability. Simulation experiments are conducted to illustrate and validate the analytical results.
{"title":"Backlog-based random access in wireless networks: Fluid limits and instability issues","authors":"Javad Ghaderiy, Sem Borstz, Phil Whitingz","doi":"10.1109/CISS.2012.6310763","DOIUrl":"https://doi.org/10.1109/CISS.2012.6310763","url":null,"abstract":"Backlog-based wireless access schemes are simple and inherently distributed, yet provide a striking capability to match the optimal throughput performance of centralized scheduling mechanisms in a wide range of scenarios. Unfortunately, the type of activation rules for which throughput optimality has been established, may result in excessive backlogs and delays. The use of more aggressive/persistent access schemes than these can improve the delay performance, but does not offer any universal maximum-stability guarantees. Motivated by the above issues, we use fluid limits to explore the (in)stability properties of backlog-based random-access algorithms. Such fluid limits have varying qualitative properties, dependent on the specific scenario, ranging from ones with smooth deterministic features, to others which exhibit random oscillatory characteristics. It turns out that more aggressive access schemes continue to provide maximum stability in some networks, e.g. complete interference graphs. As we show however, in other topologies such schemes can drive the system into inefficient states and thus cause instability. Simulation experiments are conducted to illustrate and validate the analytical results.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"1 1","pages":"15-22"},"PeriodicalIF":0.0,"publicationDate":"2012-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73439953","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 : 2011-05-09DOI: 10.1109/WIOPT.2011.5930049
Qingsi Wang, M. Liu
We observe that in a multi-channel system, an opportunistic channel access scheme that solely focuses on channel quality sensing measured by received SNR may induce users to use channels that, while providing better signals, are more congested. Ultimately the notion of channel quality should include both the signal quality and the level of congestion, and a good multi-channel access scheme should take both into account in deciding which channel to use and when. Motivated by this, we focus on the congestion aspect and examine what type of dynamic channel switching schemes may result in the best system throughput performance. Specifically we derive the stability region of a multi-user multi-channel WLAN system and determine the throughput optimal channel switching scheme within a certain class of schemes.
{"title":"Throughput optimal switching in multi-channel WLANs","authors":"Qingsi Wang, M. Liu","doi":"10.1109/WIOPT.2011.5930049","DOIUrl":"https://doi.org/10.1109/WIOPT.2011.5930049","url":null,"abstract":"We observe that in a multi-channel system, an opportunistic channel access scheme that solely focuses on channel quality sensing measured by received SNR may induce users to use channels that, while providing better signals, are more congested. Ultimately the notion of channel quality should include both the signal quality and the level of congestion, and a good multi-channel access scheme should take both into account in deciding which channel to use and when. Motivated by this, we focus on the congestion aspect and examine what type of dynamic channel switching schemes may result in the best system throughput performance. Specifically we derive the stability region of a multi-user multi-channel WLAN system and determine the throughput optimal channel switching scheme within a certain class of schemes.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"22 1","pages":"383-388"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83303972","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291555
A. Ephremides
Cooperative Techniques in Wireless Networking have been developed mostly at the physical layer and are based on the notion of relaying and space-time codes. However, it is possible to also use the idea of cooperation at the MAC and Network layers in very simple ways that provide further performance improvements. We focus on the objective of stable throughput region which requires that delays are finite when packet arrivals are random and demonstrate how simple relaying can increase the region of arrival rates that can be accommodated with finite delays. The reasons for the improvement are subtle and suggest far-reaching ossibilities regarding “stable capacity regions”. Also, we consider another form of cooperative routing for the case of sensor networks and again demonstrate how cooperation can be thought of in a much broader sense than the one that has prevailed until now.
{"title":"Cooperation at the network level","authors":"A. Ephremides","doi":"10.1109/WIOPT.2009.5291555","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291555","url":null,"abstract":"Cooperative Techniques in Wireless Networking have been developed mostly at the physical layer and are based on the notion of relaying and space-time codes. However, it is possible to also use the idea of cooperation at the MAC and Network layers in very simple ways that provide further performance improvements. We focus on the objective of stable throughput region which requires that delays are finite when packet arrivals are random and demonstrate how simple relaying can increase the region of arrival rates that can be accommodated with finite delays. The reasons for the improvement are subtle and suggest far-reaching ossibilities regarding “stable capacity regions”. Also, we consider another form of cooperative routing for the case of sensor networks and again demonstrate how cooperation can be thought of in a much broader sense than the one that has prevailed until now.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"64 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84213909","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291550
T. Weissman
Inspired by control theory, we attempt to introduce action into a few classical Shannon-theoretic frameworks. This attempt gives rise to problems ranging from source coding with a limited budget of side information measurements, through coding for computer memories with a rewrite option, to communication with non-causal feedback. I will describe these problems, along with some solutions and open questions. Based on recent and ongoing work with Haim Permuter, Yossef Steinberg, and Sergio Verdu
{"title":"Where is the action in information theory","authors":"T. Weissman","doi":"10.1109/WIOPT.2009.5291550","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291550","url":null,"abstract":"Inspired by control theory, we attempt to introduce action into a few classical Shannon-theoretic frameworks. This attempt gives rise to problems ranging from source coding with a limited budget of side information measurements, through coding for computer memories with a rewrite option, to communication with non-causal feedback. I will describe these problems, along with some solutions and open questions. Based on recent and ongoing work with Haim Permuter, Yossef Steinberg, and Sergio Verdu","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"38 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88306226","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291553
T. Marzetta
The ubiquity of inexpensive sensors implies that we can measure vector-valued data of ever increasing dimension. But the number of independent measurements of the data vector is limited so the sample covariance matrix is usually singular. The traditional remedy for singularity is diagonal loading - the addition of a small identity matrix to make the covariance estimate invertible. An alternative to diagonal loading is to reduce the dimension of the data vectors to be smaller than the number of independent observations through an ensemble of isotropically random (Haar measure) unitary matrices. For every member of the unitary ensemble, the shortened data vectors yield a statistically meaningful, invertible covariance estimate from which we can compute an estimate for the ultimate desired quantity. The final step is to take the expectation of this estimate with respect to the unitary ensemble. For a class of applications that includes adaptive spectral estimation, the design of a linear estimator, and supervised learning the random matrix approach results in an estimate for the inverse covariance matrix which preserves the eigenvectors of the sample covariance matrix, but alters the eigenvalues in a nontrivial manner. A closed-form expression for the expectation over the unitary ensemble eludes us, but we have obtained a tractable asymptotic expression. Preliminary numerical results indicate considerable promise for this approach.
{"title":"Lifting the curse of dimensionality: a random matrix-theoretic approach","authors":"T. Marzetta","doi":"10.1109/WIOPT.2009.5291553","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291553","url":null,"abstract":"The ubiquity of inexpensive sensors implies that we can measure vector-valued data of ever increasing dimension. But the number of independent measurements of the data vector is limited so the sample covariance matrix is usually singular. The traditional remedy for singularity is diagonal loading - the addition of a small identity matrix to make the covariance estimate invertible. An alternative to diagonal loading is to reduce the dimension of the data vectors to be smaller than the number of independent observations through an ensemble of isotropically random (Haar measure) unitary matrices. For every member of the unitary ensemble, the shortened data vectors yield a statistically meaningful, invertible covariance estimate from which we can compute an estimate for the ultimate desired quantity. The final step is to take the expectation of this estimate with respect to the unitary ensemble. For a class of applications that includes adaptive spectral estimation, the design of a linear estimator, and supervised learning the random matrix approach results in an estimate for the inverse covariance matrix which preserves the eigenvectors of the sample covariance matrix, but alters the eigenvalues in a nontrivial manner. A closed-form expression for the expectation over the unitary ensemble eludes us, but we have obtained a tractable asymptotic expression. Preliminary numerical results indicate considerable promise for this approach.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"70 3 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80309110","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291552
Suman Banerjee
{"title":"Towards client-assisted management in large-scale wireless networks","authors":"Suman Banerjee","doi":"10.1109/WIOPT.2009.5291552","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291552","url":null,"abstract":"","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"98 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85825338","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291549
Ratul Mahajan
No abstract provided. The document was not made available for publication as part of the conference proceedings.
没有提供摘要。该文件没有作为会议记录的一部分提供出版。
{"title":"Using redundancy to enable interactive communication for moving vehicles","authors":"Ratul Mahajan","doi":"10.1109/WIOPT.2009.5291549","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291549","url":null,"abstract":"No abstract provided. The document was not made available for publication as part of the conference proceedings.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"72 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79679072","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291551
F. Baccelli
Summary form only given, as follows. In this talk, we will discuss some problems related to cooperative spectrum sensing, and show how random matrix theory can help to address them. We will propose a simple test for frequency band sensing in wireless networks. The test is based on the analysis of the ratio of the extreme eigenvalues related to the gain matrix of the channel. The novelty relies in the fact that the test does not require the knowledge of the noise statistics. Large random matrix results allow us to build the threshold for the test, and also to study its type II error. This in particular enables us to compare this test with a different although popular test already proposed in the literature. We will show that our test is uniformly more powerful.
{"title":"Time and space averages in large wireless networks","authors":"F. Baccelli","doi":"10.1109/WIOPT.2009.5291551","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291551","url":null,"abstract":"Summary form only given, as follows. In this talk, we will discuss some problems related to cooperative spectrum sensing, and show how random matrix theory can help to address them. We will propose a simple test for frequency band sensing in wireless networks. The test is based on the analysis of the ratio of the extreme eigenvalues related to the gain matrix of the channel. The novelty relies in the fact that the test does not require the knowledge of the noise statistics. Large random matrix results allow us to build the threshold for the test, and also to study its type II error. This in particular enables us to compare this test with a different although popular test already proposed in the literature. We will show that our test is uniformly more powerful.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"154 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76612458","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 : 2009-06-23DOI: 10.1109/WIOPT.2009.5291557
V. Anantharam
Multiuser information-theoretic analysis of achievable communication rate regions over networks traditionally assumes that individual sources of information are independent.
多用户信息论分析在网络上可达到的通信速率区域传统上假定各个信息源是独立的。
{"title":"Recent progress in multiuser information theory with correlated sources","authors":"V. Anantharam","doi":"10.1109/WIOPT.2009.5291557","DOIUrl":"https://doi.org/10.1109/WIOPT.2009.5291557","url":null,"abstract":"Multiuser information-theoretic analysis of achievable communication rate regions over networks traditionally assumes that individual sources of information are independent.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"123 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2009-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76720013","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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