We consider a spread-spectrum channelization based secondary network that operates cognitively to coexist with primary users. A new framework for cross-layer design that incorporates adaptation between spectrum-spreading channelization and routing is proposed. Joint power and spreading code allocation in conjunction of the back-pressure routing is developed to optimize the throughput over the whole network. The preliminary simulation results demonstrate significant performance gains compared to random spreading code assignment algorithm.
{"title":"Towards joint routing and spread-spectrum channelization in cognitive ad hoc networks","authors":"Kanke Gao, Lei Ding","doi":"10.1145/1921206.1921225","DOIUrl":"https://doi.org/10.1145/1921206.1921225","url":null,"abstract":"We consider a spread-spectrum channelization based secondary network that operates cognitively to coexist with primary users. A new framework for cross-layer design that incorporates adaptation between spectrum-spreading channelization and routing is proposed. Joint power and spreading code allocation in conjunction of the back-pressure routing is developed to optimize the throughput over the whole network. The preliminary simulation results demonstrate significant performance gains compared to random spreading code assignment algorithm.","PeriodicalId":325024,"journal":{"name":"CoNEXT '10 Student Workshop","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122075806","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}
Cloud services are radically changing the way we access the information from the Internet and how the "digital goods" are delivered to users. To enable such services, large scale data centers are deployed at various geographical locations, and the contents are replicated at multiple locations to achieve better availability and reliability. However, it is not clear given these multiple data centers how content providers place the content and how a user query is served from the cloud. In this paper, we propose a comprehensive, yet simple and intuitive, approach that can be employed to understand the data center driven content distribution using active measurements. Additionally, applying this method on YouTube, we find that YouTube uses data-centers in more than 50 locations, and that it employs an interesting "3-step" approach to deliver videos to clients in a location-aware manner.
{"title":"Understanding data-center driven content distribution","authors":"Vijay Kumar Adhikari, Sourabh Jain, Gyan Ranjan, Zhi-Li Zhang","doi":"10.1145/1921206.1921232","DOIUrl":"https://doi.org/10.1145/1921206.1921232","url":null,"abstract":"Cloud services are radically changing the way we access the information from the Internet and how the \"digital goods\" are delivered to users. To enable such services, large scale data centers are deployed at various geographical locations, and the contents are replicated at multiple locations to achieve better availability and reliability. However, it is not clear given these multiple data centers how content providers place the content and how a user query is served from the cloud.\u0000 In this paper, we propose a comprehensive, yet simple and intuitive, approach that can be employed to understand the data center driven content distribution using active measurements. Additionally, applying this method on YouTube, we find that YouTube uses data-centers in more than 50 locations, and that it employs an interesting \"3-step\" approach to deliver videos to clients in a location-aware manner.","PeriodicalId":325024,"journal":{"name":"CoNEXT '10 Student Workshop","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123301015","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}
The Internet has matured to a mission-critical infrastructure, and recently attracted much attention at political and legal levels in many countries. Civil actions regarding the Internet infrastructure require a thorough understanding of the national components of the global Internet to foresee possible impacts of regulations and operations at a country-level. In this paper we report on a methodology, tool chain and results for identifying and classifying a 'national Internet'. We argue for the importance to consider individual IP-blocks instead of prefixes and quantify the effects of our proposed approach. The methods have been applied to identify a 'German Internet', but are designed general enough to work for most countries, as well.
{"title":"A framework for nation-centric classification and observation of the internet","authors":"Matthias Wählisch, Sebastian Meiling, T. Schmidt","doi":"10.1145/1921206.1921223","DOIUrl":"https://doi.org/10.1145/1921206.1921223","url":null,"abstract":"The Internet has matured to a mission-critical infrastructure, and recently attracted much attention at political and legal levels in many countries. Civil actions regarding the Internet infrastructure require a thorough understanding of the national components of the global Internet to foresee possible impacts of regulations and operations at a country-level. In this paper we report on a methodology, tool chain and results for identifying and classifying a 'national Internet'. We argue for the importance to consider individual IP-blocks instead of prefixes and quantify the effects of our proposed approach. The methods have been applied to identify a 'German Internet', but are designed general enough to work for most countries, as well.","PeriodicalId":325024,"journal":{"name":"CoNEXT '10 Student Workshop","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121034394","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}
This paper proposes a new spectrum handoff approach for multiple channels cognitive radio networks to support delay sensitive applications such as VoIP. The delay probability is estimated to determine whether and how to perform the handoff operation. Moreover, traffic prediction on licensed channels is also required in order to estimate the impairment in the delay. Since, the error of prediction still cannot be solved totally, therefore the backup channel solution is proposed to reduce the harmfulness of this impact. The delay probability density function is through various strategies of spectrum handoff for multiple channels cognitive radio.
{"title":"Spectrum handoff strategies for multiple channels cognitive radio network","authors":"Adisorn Lertsinsrubtavee, N. Malouch, S. Fdida","doi":"10.1145/1921206.1921228","DOIUrl":"https://doi.org/10.1145/1921206.1921228","url":null,"abstract":"This paper proposes a new spectrum handoff approach for multiple channels cognitive radio networks to support delay sensitive applications such as VoIP. The delay probability is estimated to determine whether and how to perform the handoff operation. Moreover, traffic prediction on licensed channels is also required in order to estimate the impairment in the delay. Since, the error of prediction still cannot be solved totally, therefore the backup channel solution is proposed to reduce the harmfulness of this impact. The delay probability density function is through various strategies of spectrum handoff for multiple channels cognitive radio.","PeriodicalId":325024,"journal":{"name":"CoNEXT '10 Student Workshop","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125856334","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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