Pub Date : 2010-12-01DOI: 10.1109/GLOCOM.2010.5684119
Yi Tang, Junchen Jiang, Xiaofei Wang, B. Liu, Yang Xu
Multi-string matching is a key technique for implementing network security applications like Network Intrusion Detection Systems (NIDS). Existing DFA-based approaches always tradeoff between memory and throughput, and fail to has the best of both worlds. This paper extends the classic longest prefix principle from single-character to multi-character string matching and proposes a multi-string matching acceleration scheme named Independent Parallel Compact Finite Automata (PC-FA). In the scheme, DFA is divided into k PC-FAs, each of which can process one character from the input stream, achieving a speedup up to k with reduced memory occupation. Theoretical proof is given for the equivalency between traditional DFA and PC-FA approach. Experi-mental evaluations show that seven times of speedup can be practically achieved with a reduced memory size than up-to-date DFA-based compression approaches.
{"title":"Independent Parallel Compact Finite Automatons for Accelerating Multi-String Matching","authors":"Yi Tang, Junchen Jiang, Xiaofei Wang, B. Liu, Yang Xu","doi":"10.1109/GLOCOM.2010.5684119","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5684119","url":null,"abstract":"Multi-string matching is a key technique for implementing network security applications like Network Intrusion Detection Systems (NIDS). Existing DFA-based approaches always tradeoff between memory and throughput, and fail to has the best of both worlds. This paper extends the classic longest prefix principle from single-character to multi-character string matching and proposes a multi-string matching acceleration scheme named Independent Parallel Compact Finite Automata (PC-FA). In the scheme, DFA is divided into k PC-FAs, each of which can process one character from the input stream, achieving a speedup up to k with reduced memory occupation. Theoretical proof is given for the equivalency between traditional DFA and PC-FA approach. Experi-mental evaluations show that seven times of speedup can be practically achieved with a reduced memory size than up-to-date DFA-based compression approaches.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"10 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78117935","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5684288
Yiyue Wu, Andreas Achtzehn, M. Petrova, P. Mähönen, A. Calderbank
The use of beamforming to enable higher data rates in telecommunications is widely appreciated, but performance gains are typically calculated assuming delay-free feedback from the receiver and neglecting processing time. This paper introduces a mathematical framework based on outage probability that measures the extent to which current channel state information is accurate. Performance gains from beamforming can then be evaluated as a function of the currency of system state. Results are provided for Multiple Input Single Output (MISO) and for Multiuser Multiple Input Multiple Output (MU-MIMO) systems. Outage probabilities and effective diversity orders are calculated for widely used methods of beamforming such as Transmit Antenna Selection as a function of the speed of channel variation.
{"title":"On the Effect of Feedback Delay on Limited-Rate Beamforming Systems","authors":"Yiyue Wu, Andreas Achtzehn, M. Petrova, P. Mähönen, A. Calderbank","doi":"10.1109/GLOCOM.2010.5684288","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5684288","url":null,"abstract":"The use of beamforming to enable higher data rates in telecommunications is widely appreciated, but performance gains are typically calculated assuming delay-free feedback from the receiver and neglecting processing time. This paper introduces a mathematical framework based on outage probability that measures the extent to which current channel state information is accurate. Performance gains from beamforming can then be evaluated as a function of the currency of system state. Results are provided for Multiple Input Single Output (MISO) and for Multiuser Multiple Input Multiple Output (MU-MIMO) systems. Outage probabilities and effective diversity orders are calculated for widely used methods of beamforming such as Transmit Antenna Selection as a function of the speed of channel variation.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"28 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79873354","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5683651
Chenglong Li, Y. Xue, Yingfei Dong, Dongsheng Wang
Thunder (also called Xunlei) is the most popular P2P file sharing application in China and probably the most popular P2P software in term of traffic volume and number of users. Precisely identifying Thunder traffic can help network administrators to efficiently manage their networks. Traditional methods of identifying P2P traffic such as port-based or content-based approaches are ineffective to Thunder traffic, because of its dynamic packet format, flexible port numbers, and payload encryption. In this paper, we developed a novel Heuristic Message Clustering approach (HMC) to identify Thunder traffic, and obtain its state machine and key transaction cycles, thus identifying Thunder traffic fast and accurately. We first evaluate our method in a controlled environment and then with real campus traces. The results show that HMC is able to identify Thunder flows with high precision and low error rate.
{"title":"HMC: A Novel Mechanism for Identifying Encrypted P2P Thunder Traffic","authors":"Chenglong Li, Y. Xue, Yingfei Dong, Dongsheng Wang","doi":"10.1109/GLOCOM.2010.5683651","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5683651","url":null,"abstract":"Thunder (also called Xunlei) is the most popular P2P file sharing application in China and probably the most popular P2P software in term of traffic volume and number of users. Precisely identifying Thunder traffic can help network administrators to efficiently manage their networks. Traditional methods of identifying P2P traffic such as port-based or content-based approaches are ineffective to Thunder traffic, because of its dynamic packet format, flexible port numbers, and payload encryption. In this paper, we developed a novel Heuristic Message Clustering approach (HMC) to identify Thunder traffic, and obtain its state machine and key transaction cycles, thus identifying Thunder traffic fast and accurately. We first evaluate our method in a controlled environment and then with real campus traces. The results show that HMC is able to identify Thunder flows with high precision and low error rate.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"17 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80359716","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5684111
T. Ngatched, A. Alfa, Jun Cai
This paper presents an improvement of the reliability-based iterative majority-logic decoding algorithms for regular low-density parity-check (LDPC) codes proposed by Huang et al. We improve the computation of the extrinsic information that is used to update the reliability measure of each received bit in each iteration with some kind of reliability measures of the check-sums that are orthogonal on the considered bit. The improved algorithm achieves a significant gain over the standard one with only a modest increase in computational complexity.
{"title":"An Improvement on the Soft Reliability-Based Iterative Majority-Logic Decoding Algorithm for LDPC Codes","authors":"T. Ngatched, A. Alfa, Jun Cai","doi":"10.1109/GLOCOM.2010.5684111","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5684111","url":null,"abstract":"This paper presents an improvement of the reliability-based iterative majority-logic decoding algorithms for regular low-density parity-check (LDPC) codes proposed by Huang et al. We improve the computation of the extrinsic information that is used to update the reliability measure of each received bit in each iteration with some kind of reliability measures of the check-sums that are orthogonal on the considered bit. The improved algorithm achieves a significant gain over the standard one with only a modest increase in computational complexity.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"94 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80367469","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5683883
Alia Bellabas, S. Lahoud, M. Molnár
The NP-hard QoS Multicast Routing (QoSMR) is one of the most challenging problems in recent networks. In this paper, we investigate the QoSMR problem as well as its different existing formulations. We analyze the limitations of these formulations and propose a novel one. The main advantage of our formulation is that it considers not only the quality of the multicast subgraph formed by the computed paths, but also takes into account the end-to-end quality of each of these paths. Moreover, we study the state of the art proposal for solving the QoSMR problem and show that the well-known MAMCRA algorithm can be very expensive in computation time. Therefore, we propose two efficient heuristics based on the computation of shortest paths. Extensive simulations are performed, and obtained results prove that these fast heuristics have bounded computation time and find satisfying solutions for the QoS requirements.
{"title":"Fast Heuristics for the QoS Multicast Routing Problem","authors":"Alia Bellabas, S. Lahoud, M. Molnár","doi":"10.1109/GLOCOM.2010.5683883","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5683883","url":null,"abstract":"The NP-hard QoS Multicast Routing (QoSMR) is one of the most challenging problems in recent networks. In this paper, we investigate the QoSMR problem as well as its different existing formulations. We analyze the limitations of these formulations and propose a novel one. The main advantage of our formulation is that it considers not only the quality of the multicast subgraph formed by the computed paths, but also takes into account the end-to-end quality of each of these paths. Moreover, we study the state of the art proposal for solving the QoSMR problem and show that the well-known MAMCRA algorithm can be very expensive in computation time. Therefore, we propose two efficient heuristics based on the computation of shortest paths. Extensive simulations are performed, and obtained results prove that these fast heuristics have bounded computation time and find satisfying solutions for the QoS requirements.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"34 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82153363","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5684290
Ying Zhu
The technological advances in mobile devices have resulted in increasing numbers of applications on them, and users use these applications to create lots of data. Due to the truly ubiquitous nature of these devices, the data is created potentially at all times of the day and in different wireless environments, e.g., at home, on the subway, at a coffeeshop. These data must eventually be uploaded to the server cloud from the mobile device by connecting to a wireless network. In different environments, the available wireless networks change, and the cost of connecting to them in order to upload these data also changes. For different applications, the preference for the uploading time for their data may be very different. We study the problem of optimizing the time for uploading based on the preferenc measure as well as the cost of the wireless network available at the time of uploading. Furthermore, because the wireless environment is dynamic and nondeterministic in the future, we use machine learning techniques for modeling user mobility patterns and predicting the wireless network in the near future, to assist in finding the optimal uploading time.
{"title":"Optimizing Upload Time of Data from Mobile Devices","authors":"Ying Zhu","doi":"10.1109/GLOCOM.2010.5684290","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5684290","url":null,"abstract":"The technological advances in mobile devices have resulted in increasing numbers of applications on them, and users use these applications to create lots of data. Due to the truly ubiquitous nature of these devices, the data is created potentially at all times of the day and in different wireless environments, e.g., at home, on the subway, at a coffeeshop. These data must eventually be uploaded to the server cloud from the mobile device by connecting to a wireless network. In different environments, the available wireless networks change, and the cost of connecting to them in order to upload these data also changes. For different applications, the preference for the uploading time for their data may be very different. We study the problem of optimizing the time for uploading based on the preferenc measure as well as the cost of the wireless network available at the time of uploading. Furthermore, because the wireless environment is dynamic and nondeterministic in the future, we use machine learning techniques for modeling user mobility patterns and predicting the wireless network in the near future, to assist in finding the optimal uploading time.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"2675 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82181719","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5683434
Shengliang Peng, Xi Yang, Shuli Shu, Lan Tang, Xiuying Cao
This paper investigates the issue of minimizing the detection time while guaranteeing the desired detection accuracy in cooperative primary user detection for cognitive radio. To achieve this goal, the sequential cooperative energy detection (SCED) scheme is firstly introduced. This scheme implements sequential probability ratio test to make final decisions and can guarantee the desired detection accuracy with less detection time compared with other schemes. Then, detection time in the SCED scheme is minimized by choosing an optimum sample number. Expressions for the optimum sample number and the minimum detection time in four typical scenarios are also derived. Simulation results are presented to illustrate the benefits of the SCED scheme and to examine the optimum sample number as well as the minimum detection time.
{"title":"Minimizing Detection Time While Guaranteeing Desired Detection Accuracy in Cooperative Primary User Detection","authors":"Shengliang Peng, Xi Yang, Shuli Shu, Lan Tang, Xiuying Cao","doi":"10.1109/GLOCOM.2010.5683434","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5683434","url":null,"abstract":"This paper investigates the issue of minimizing the detection time while guaranteeing the desired detection accuracy in cooperative primary user detection for cognitive radio. To achieve this goal, the sequential cooperative energy detection (SCED) scheme is firstly introduced. This scheme implements sequential probability ratio test to make final decisions and can guarantee the desired detection accuracy with less detection time compared with other schemes. Then, detection time in the SCED scheme is minimized by choosing an optimum sample number. Expressions for the optimum sample number and the minimum detection time in four typical scenarios are also derived. Simulation results are presented to illustrate the benefits of the SCED scheme and to examine the optimum sample number as well as the minimum detection time.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"57 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82279682","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5683908
Charles-Francois Natali, N. Vaidya, Victor K. Y. Wu
We present two singulation schemes for passive RFID systems. The first scheme, called expanding horizon, uses interrogator transmit power control to singulate tags in concentric annuli. We show through analysis that this scheme is very time-efficient and conserves energy. Our second scheme is a combination parallel interrogation and TDMA scheme that applies to multiple interrogator situations. It leverages the capture effect to singulate many tags, even when these tags may be receiving signals from multiple interrogators. This provides a time-efficient scheme, as shown in our simulations.
{"title":"Expanding Horizon and Capture Effect in RFID Singulation","authors":"Charles-Francois Natali, N. Vaidya, Victor K. Y. Wu","doi":"10.1109/GLOCOM.2010.5683908","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5683908","url":null,"abstract":"We present two singulation schemes for passive RFID systems. The first scheme, called expanding horizon, uses interrogator transmit power control to singulate tags in concentric annuli. We show through analysis that this scheme is very time-efficient and conserves energy. Our second scheme is a combination parallel interrogation and TDMA scheme that applies to multiple interrogator situations. It leverages the capture effect to singulate many tags, even when these tags may be receiving signals from multiple interrogators. This provides a time-efficient scheme, as shown in our simulations.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"47 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81361580","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5684027
Chao Zou, Chunxiao Chigan
The paradigm of dynamic spectrum access, an intrinsic characteristic of the cognitive radio network (CRN), embraces new opportunity for protecting the privacy of communication content through random channel hopping patterns, which are hard to follow by adversaries. Different from conventional DSA where each active CR user only accesses the spectrum once, the confidentiality driven DSA requires every active user to hop over multiple channels during one transmission session. Hence the DSA process is modeled as a fractional coloring process. By artfully converting two-dimensional color to one-dimensional color through vertex expansion, a Latin square (LS) based DSA is proposed, with confidentiality requirements embedded. Theoretic analysis and simulation results verify the feasibility of the DSA based cryptography and illustrates how confidentiality requirement affects the spectrum utilization efficiency.
{"title":"Dynamic Spectrum Allocation Based Confidentiality for Cognitive Radio Networks","authors":"Chao Zou, Chunxiao Chigan","doi":"10.1109/GLOCOM.2010.5684027","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5684027","url":null,"abstract":"The paradigm of dynamic spectrum access, an intrinsic characteristic of the cognitive radio network (CRN), embraces new opportunity for protecting the privacy of communication content through random channel hopping patterns, which are hard to follow by adversaries. Different from conventional DSA where each active CR user only accesses the spectrum once, the confidentiality driven DSA requires every active user to hop over multiple channels during one transmission session. Hence the DSA process is modeled as a fractional coloring process. By artfully converting two-dimensional color to one-dimensional color through vertex expansion, a Latin square (LS) based DSA is proposed, with confidentiality requirements embedded. Theoretic analysis and simulation results verify the feasibility of the DSA based cryptography and illustrates how confidentiality requirement affects the spectrum utilization efficiency.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"60 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78667690","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 : 2010-12-01DOI: 10.1109/GLOCOM.2010.5683830
Yingxi Liu, Nikhil Kundargi, A. Tewfik
Traditional cognitive radio protocols rely on identifying intervals of time when a channel is available to secondary users. To date, the detection of such opportunities has relied on single threshold based binary hypothesis testing schemes. In this paper, we describe the shortcomings of traditional single threshold transmit opportunity methods. We then propose a hysteresis based detection scheme that uses two different thresholds for detecting that a channel that was unavailable has become available or that an available channel is no longer available. We provide numerical simulation and experimental results to show that the proposed double threshold approach reduces interference to the primary network and enhances the throughput of the secondary network.
{"title":"Temporal Spectrum Sensing in Packet-Based Network Using Double Thresholds","authors":"Yingxi Liu, Nikhil Kundargi, A. Tewfik","doi":"10.1109/GLOCOM.2010.5683830","DOIUrl":"https://doi.org/10.1109/GLOCOM.2010.5683830","url":null,"abstract":"Traditional cognitive radio protocols rely on identifying intervals of time when a channel is available to secondary users. To date, the detection of such opportunities has relied on single threshold based binary hypothesis testing schemes. In this paper, we describe the shortcomings of traditional single threshold transmit opportunity methods. We then propose a hysteresis based detection scheme that uses two different thresholds for detecting that a channel that was unavailable has become available or that an available channel is no longer available. We provide numerical simulation and experimental results to show that the proposed double threshold approach reduces interference to the primary network and enhances the throughput of the secondary network.","PeriodicalId":6448,"journal":{"name":"2010 IEEE Global Telecommunications Conference GLOBECOM 2010","volume":"35 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78795845","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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