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Atoosa Dalili Shoaei - One of the best experts on this subject based on the ideXlab platform.

  • efficient lte wi fi coexistence in unlicensed spectrum using virtual Network Entity optimization and performance analysis
    IEEE Transactions on Communications, 2018
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Lengoc
    Abstract:

    Long-term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular Networks. Although this approach brings higher capacity for LTE Networks, the Wi-Fi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both Networks are controlled by a higher level Network Entity. In such a model, LTE users can transmit in the assigned time-slots, while Wi-Fi users can compete with each other by using $p$ -persistent carrier sense multiple access (CSMA) in their exclusive time-share. In an unsaturated Network, at each duty cycle, the time-division multiple access (TDMA) scheduling for LTE users and $p$ values for Wi-Fi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming and monomial approximations. Aiming to address the quality-of-service assurance for LTE users, an upper bound for average delay of these users is obtained. This analysis could be a basis for the admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the Wi-Fi throughput requirement.

  • Efficient LTE/Wi-Fi Coexistence in Unlicensed Spectrum Using Virtual Network Entity: Optimization and Performance Analysis
    IEEE Transactions on Communications, 2018
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Le-ngoc
    Abstract:

    Long-term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular Networks. Although this approach brings higher capacity for LTE Networks, the Wi-Fi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both Networks are controlled by a higher level Network Entity. In such a model, LTE users can transmit in the assigned time-slots, while Wi-Fi users can compete with each other by using $p$ -persistent carrier sense multiple access (CSMA) in their exclusive time-share. In an unsaturated Network, at each duty cycle, the time-division multiple access (TDMA) scheduling for LTE users and $p$ values for Wi-Fi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming and monomial approximations. Aiming to address the quality-of-service assurance for LTE users, an upper bound for average delay of these users is obtained. This analysis could be a basis for the admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the Wi-Fi throughput requirement.

  • GLOBECOM - Efficient LTE/WiFi Coexistence in Unlicensed Spectrum Using Virtual Network Entity
    GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Le-ngoc, Mohamed Adel Salem
    Abstract:

    Due to the increasing demand for mobile traffic, the unlicensed band operation for LTE is proposed by mobile operators. Although by using this approach higher capacity can be achieved for LTE, performance of other wireless technologies operating in this band such as WiFi can be degraded significantly. In order to enable efficient LTE/WiFi coexistence, we consider a coordinated structure via a virtual Network Entity. LTE users can transmit in the assigned time-slots, while WiFi users can compete with each other by using p-persistent CSMA in their exclusive time-share. In an unsaturated Network, at each duty cycle, the TDMA scheduling for LTE users and p values for WiFi users are updated to maximize the overall Network throughput subject to a constraint on the minimum acceptable throughput for WiFi. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming (CGP) and monomial approximations. The simulation results reveal the performance gains of the proposed algorithm in preserving the WiFi throughput requirement.

Tho Le-ngoc - One of the best experts on this subject based on the ideXlab platform.

  • Efficient LTE/Wi-Fi Coexistence in Unlicensed Spectrum Using Virtual Network Entity: Optimization and Performance Analysis
    IEEE Transactions on Communications, 2018
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Le-ngoc
    Abstract:

    Long-term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular Networks. Although this approach brings higher capacity for LTE Networks, the Wi-Fi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both Networks are controlled by a higher level Network Entity. In such a model, LTE users can transmit in the assigned time-slots, while Wi-Fi users can compete with each other by using $p$ -persistent carrier sense multiple access (CSMA) in their exclusive time-share. In an unsaturated Network, at each duty cycle, the time-division multiple access (TDMA) scheduling for LTE users and $p$ values for Wi-Fi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming and monomial approximations. Aiming to address the quality-of-service assurance for LTE users, an upper bound for average delay of these users is obtained. This analysis could be a basis for the admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the Wi-Fi throughput requirement.

  • GLOBECOM - Efficient LTE/WiFi Coexistence in Unlicensed Spectrum Using Virtual Network Entity
    GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Le-ngoc, Mohamed Adel Salem
    Abstract:

    Due to the increasing demand for mobile traffic, the unlicensed band operation for LTE is proposed by mobile operators. Although by using this approach higher capacity can be achieved for LTE, performance of other wireless technologies operating in this band such as WiFi can be degraded significantly. In order to enable efficient LTE/WiFi coexistence, we consider a coordinated structure via a virtual Network Entity. LTE users can transmit in the assigned time-slots, while WiFi users can compete with each other by using p-persistent CSMA in their exclusive time-share. In an unsaturated Network, at each duty cycle, the TDMA scheduling for LTE users and p values for WiFi users are updated to maximize the overall Network throughput subject to a constraint on the minimum acceptable throughput for WiFi. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming (CGP) and monomial approximations. The simulation results reveal the performance gains of the proposed algorithm in preserving the WiFi throughput requirement.

Tho Lengoc - One of the best experts on this subject based on the ideXlab platform.

  • efficient lte wi fi coexistence in unlicensed spectrum using virtual Network Entity optimization and performance analysis
    IEEE Transactions on Communications, 2018
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Lengoc
    Abstract:

    Long-term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular Networks. Although this approach brings higher capacity for LTE Networks, the Wi-Fi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both Networks are controlled by a higher level Network Entity. In such a model, LTE users can transmit in the assigned time-slots, while Wi-Fi users can compete with each other by using $p$ -persistent carrier sense multiple access (CSMA) in their exclusive time-share. In an unsaturated Network, at each duty cycle, the time-division multiple access (TDMA) scheduling for LTE users and $p$ values for Wi-Fi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming and monomial approximations. Aiming to address the quality-of-service assurance for LTE users, an upper bound for average delay of these users is obtained. This analysis could be a basis for the admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the Wi-Fi throughput requirement.

Mahsa Derakhshani - One of the best experts on this subject based on the ideXlab platform.

  • efficient lte wi fi coexistence in unlicensed spectrum using virtual Network Entity optimization and performance analysis
    IEEE Transactions on Communications, 2018
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Lengoc
    Abstract:

    Long-term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular Networks. Although this approach brings higher capacity for LTE Networks, the Wi-Fi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both Networks are controlled by a higher level Network Entity. In such a model, LTE users can transmit in the assigned time-slots, while Wi-Fi users can compete with each other by using $p$ -persistent carrier sense multiple access (CSMA) in their exclusive time-share. In an unsaturated Network, at each duty cycle, the time-division multiple access (TDMA) scheduling for LTE users and $p$ values for Wi-Fi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming and monomial approximations. Aiming to address the quality-of-service assurance for LTE users, an upper bound for average delay of these users is obtained. This analysis could be a basis for the admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the Wi-Fi throughput requirement.

  • Efficient LTE/Wi-Fi Coexistence in Unlicensed Spectrum Using Virtual Network Entity: Optimization and Performance Analysis
    IEEE Transactions on Communications, 2018
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Le-ngoc
    Abstract:

    Long-term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular Networks. Although this approach brings higher capacity for LTE Networks, the Wi-Fi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both Networks are controlled by a higher level Network Entity. In such a model, LTE users can transmit in the assigned time-slots, while Wi-Fi users can compete with each other by using $p$ -persistent carrier sense multiple access (CSMA) in their exclusive time-share. In an unsaturated Network, at each duty cycle, the time-division multiple access (TDMA) scheduling for LTE users and $p$ values for Wi-Fi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming and monomial approximations. Aiming to address the quality-of-service assurance for LTE users, an upper bound for average delay of these users is obtained. This analysis could be a basis for the admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the Wi-Fi throughput requirement.

  • GLOBECOM - Efficient LTE/WiFi Coexistence in Unlicensed Spectrum Using Virtual Network Entity
    GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017
    Co-Authors: Atoosa Dalili Shoaei, Mahsa Derakhshani, Tho Le-ngoc, Mohamed Adel Salem
    Abstract:

    Due to the increasing demand for mobile traffic, the unlicensed band operation for LTE is proposed by mobile operators. Although by using this approach higher capacity can be achieved for LTE, performance of other wireless technologies operating in this band such as WiFi can be degraded significantly. In order to enable efficient LTE/WiFi coexistence, we consider a coordinated structure via a virtual Network Entity. LTE users can transmit in the assigned time-slots, while WiFi users can compete with each other by using p-persistent CSMA in their exclusive time-share. In an unsaturated Network, at each duty cycle, the TDMA scheduling for LTE users and p values for WiFi users are updated to maximize the overall Network throughput subject to a constraint on the minimum acceptable throughput for WiFi. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming (CGP) and monomial approximations. The simulation results reveal the performance gains of the proposed algorithm in preserving the WiFi throughput requirement.

Angelos D. Keromytis - One of the best experts on this subject based on the ideXlab platform.

  • Detection and analysis of eavesdropping in anonymous communication Networks
    International Journal of Information Security, 2015
    Co-Authors: Sambuddho Chakravarty, Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis
    Abstract:

    Anonymous communication Networks, like Tor, partially protect the confidentiality of user traffic by encrypting all communications within the overlay Network. However, when the relayed traffic reaches the boundaries of the Network, toward its destination, the original user traffic is inevitably exposed to the final node on the path. As a result, users transmitting sensitive data, like authentication credentials, over such Networks, risk having their data intercepted and exposed, unless end-to-end encryption is used. Eavesdropping can be performed by malicious or compromised relay nodes, as well as any rogue Network Entity on the path toward the actual destination. Furthermore, end-to-end encryption does not assure defense against man-in-the-middle attacks. In this work, we explore the use of decoys at multiple levels for the detection of traffic interception by malicious nodes of proxy-based anonymous communication systems. Our approach relies on the injection of traffic that exposes bait credentials for decoy services requiring user authentication, and URLs to seemingly sensitive decoy documents which, when opened, invoke scripts alerting about being accessed. Our aim was to entice prospective eavesdroppers to access our decoy servers and decoy documents, using the snooped credentials and URLs. We have deployed our prototype implementation in the Tor Network using decoy IMAP, SMTP, and HTTP servers. During the course of over 30 months, our system has detected 18 cases of traffic eavesdropping that involved 14 different Tor exit nodes.

  • Detecting Traffic Snooping in Tor Using Decoys
    2012
    Co-Authors: Sambuddho Chakravarty, Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis
    Abstract:

    Abstract. Anonymous communication Networks like Tor partially protect the confidentiality of their users ’ traffic by encrypting all intraoverlay communication. However, when the relayed traffic reaches the boundaries of the overlay Network towards its actual destination, the original user traffic is inevitably exposed. At this point, unless end-toend encryption is used, sensitive user data can be snooped by a malicious or compromised exit node, or by any other rogue Network Entity on the path towards the actual destination. We explore the use of decoy traffic for the detection of traffic interception on anonymous proxying systems. Our approach is based on the injection of traffic that exposes bait credentials for decoy services that require user authentication. Our aim is to entice prospective eavesdroppers to access decoy accounts on servers under our control using the intercepted credentials. We have deployed our prototype implementation in the Tor Network using decoy IMAP and SMTP servers. During the course of ten months, our system detected ten cases of traffic interception that involved ten different Tor exit nodes. We provide a detailed analysis of the detected incidents, discuss potential improvements to our system, and outline how our approach can be extended for the detection of HTTP session hijacking attacks.

  • RAID - Detecting traffic snooping in tor using decoys
    Lecture Notes in Computer Science, 2011
    Co-Authors: Sambuddho Chakravarty, Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis, Sambuddho Chakravarty, Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis
    Abstract:

    Anonymous communication Networks like Tor partially protect the confidentiality of their users' traffic by encrypting all intra-overlay communication. However, when the relayed traffic reaches the boundaries of the overlay Network towards its actual destination, the original user traffic is inevitably exposed. At this point, unless end-to-end encryption is used, sensitive user data can be snooped by a malicious or compromised exit node, or by any other rogue Network Entity on the path towards the actual destination. We explore the use of decoy traffic for the detection of traffic interception on anonymous proxying systems. Our approach is based on the injection of traffic that exposes bait credentials for decoy services that require user authentication. Our aim is to entice prospective eavesdroppers to access decoy accounts on servers under our control using the intercepted credentials. We have deployed our prototype implementation in the Tor Network using decoy IMAP and SMTP servers. During the course of ten months, our system detected ten cases of traffic interception that involved ten different Tor exit nodes. We provide a detailed analysis of the detected incidents, discuss potential improvements to our system, and outline how our approach can be extended for the detection of HTTP session hijacking attacks.

  • Detecting Traffic Snooping in Anonymity Networks Using Decoys
    2011
    Co-Authors: Sambuddho Chakravarty, Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis, Sambuddho Chakravarty, Georgios Portokalidis, Michalis Polychronakis, Angelos D. Keromytis
    Abstract:

    Anonymous communication Networks like Tor partially protect the confidentiality of their users’ traffic by encrypting all intraoverlay communication. However, when the relayed traffic reaches the boundaries of the overlay Network towards its actual destination, the original user traffic is inevitably exposed. At this point, unless end-toend encryption is used, sensitive user data can be snooped by a malicious or compromised exit node, or by any other rogue Network Entity on the path towards the actual destination. We explore the use of decoy traffic for the detection of traffic interception on anonymous proxying systems. Our approach is based on the injection of traffic that exposes bait credentials for decoy services that require user authentication. Our aim is to entice prospective eavesdroppers to access decoy accounts on servers under our control using the intercepted credentials. We have deployed our prototype implementation in the Tor Network using decoy IMAP and SMTP servers. During the course of six months, our system detected eight cases of traffic interception that involved eight different Tor exit nodes. We provide a detailed analysis of the detected incidents, discuss potential improvements to our system, and outline how our approach can be extended for the detection of HTTP session hijacking attacks.