The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Emad Shihab - One of the best experts on this subject based on the ideXlab platform.
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A Directional-to-Directional (DtD) MAC Protocol for Ad hoc Networks
2020Co-Authors: Emad ShihabAbstract:The use of Directional antennae in ad-hoc networks has received growing attention in recent years because of the benefits including, high spatial reuse, higher antenna gains, etc. At the same time, using Directional antennae introduces new challenges. For example, the problem of deafness where receiver nodes may not hear handshake messages because their antennae beams are not pointing in the direction of the sender. To address these issues, new Directional MAC protocols are required. In the literature, the existing Directional MAC protocols assumed that nodes can operate in both Directional and omni-Directional modes. However, using both Directional and omniDirectional modes of operation leads to the asymmetry-in-gain problem and defeats the purpose of using Directional antennae [1].
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A Distributed Asynchronous Directional-to-Directional MAC Protocol for Wireless Ad Hoc Networks
IEEE Transactions on Vehicular Technology, 2009Co-Authors: Emad ShihabAbstract:The use of Directional antennas in ad hoc networks has received growing attention because of its high spatial reuse and high antenna gains. The medium access control (MAC) protocol design with Directional antennas is nontrivial due to the deafness and collision problems. The existing protocols assumed that the nodes can operate in both Directional and omniDirectional modes. However, using both modes leads to the asymmetry-in-gain problem. In this paper, we propose a Directional-to-Directional (DtD) MAC protocol, where both senders and receivers operate in a Directional-only mode. We also derive the saturation throughput of ad hoc networks using DtD MAC. The analytical and simulation results show that DtD MAC can significantly improve the throughput and maintain good fairness among competing flows. We further evaluate the DtD MAC with millimeter-wave (mmWave) communication technologies, which rely on a Directional antenna to perform well and can achieve gigabit data rates. The results obtained are exciting and show that DtD MAC is a promising candidate for mmWave ad hoc networks.
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GLOBECOM - A Distributed Directional-to-Directional MAC Protocol for Asynchronous Ad Hoc Networks
IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008Co-Authors: Emad ShihabAbstract:The use of Directional antennae in ad hoc networks has received growing attention in recent years. However, most existing Directional MAC protocols assume interchangeable Directional and omniDirectional modes of operation. Such operation reduces the spatial gain and introduces the asymmetry-in-gain problem. In this paper, we propose a Directional-to-Directional (DtD) MAC protocol for ad-hoc networks that operates in the Directional mode exclusively. The protocol is fully distributed, does not require any synchronization, eliminates the asymmetry- in-gain problem, and alleviates the deafness problem. To study the performance of the proposed DtD MAC, we develop an analytical model that estimates the saturation throughput as a function of the number of antenna sectors, packet size and number of contending nodes. The analytical results are validated by extensive simulations with the QualNet simulator. We show that the DtD MAC protocol is practical to take the advantage of Directional antennae to improve network throughput and achieve better fairness in ad-hoc networks.
Rajive Bagrodia - One of the best experts on this subject based on the ideXlab platform.
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Directional virtual carrier sensing for Directional antennas in mobile ad hoc networks
Mobile Ad Hoc Networking and Computing, 2002Co-Authors: Mineo Takai, Jay Martin, Rajive BagrodiaAbstract:This paper presents a new carrier sensing mechanism called DVCS (Directional Virtual Carrier Sensing) for wireless communication using Directional antennas. DVCS does not require specific antenna configurations or external devices. Instead it only needs information on AOA (Angle of Arrival) and antenna gain for each signal from the underlying physical device, both of which are commonly used for the adaptation of antenna pattern. DVCS also supports interoperability of Directional and omni-Directional antennas. In this study, the performance of DVCS for mobile ad hoc networks is evaluated using simulation with a realistic Directional antenna model and the full IP protocol stack. The experimental results showed that compared with omni-Directional communication, DVCS improved network capacity by a factor of 3 to 4 for a 100 node ad hoc network.
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MobiHoc - Directional virtual carrier sensing for Directional antennas in mobile ad hoc networks
Proceedings of the 3rd ACM international symposium on Mobile ad hoc networking & computing - MobiHoc '02, 2002Co-Authors: Mineo Takai, Jay Martin, Rajive BagrodiaAbstract:This paper presents a new carrier sensing mechanism called DVCS (Directional Virtual Carrier Sensing) for wireless communication using Directional antennas. DVCS does not require specific antenna configurations or external devices. Instead it only needs information on AOA (Angle of Arrival) and antenna gain for each signal from the underlying physical device, both of which are commonly used for the adaptation of antenna pattern. DVCS also supports interoperability of Directional and omni-Directional antennas. In this study, the performance of DVCS for mobile ad hoc networks is evaluated using simulation with a realistic Directional antenna model and the full IP protocol stack. The experimental results showed that compared with omni-Directional communication, DVCS improved network capacity by a factor of 3 to 4 for a 100 node ad hoc network.
Leandros Tassiulas - One of the best experts on this subject based on the ideXlab platform.
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CDR-MAC: A protocol for full exploitation of Directional antennas in ad hoc wireless networks
IEEE Transactions on Mobile Computing, 2008Co-Authors: Thanasis Korakis, Gentian Jakllari, Leandros TassiulasAbstract:In this paper, we propose a new Medium Access Control (MAC) protocol for full exploitation of Directional antennas in wireless networks. The protocol introduces a circular Directional transmission of the Request To Send (RTS) control packet, spreading around a station information about the intended communication. The stations that receive the Directional RTS, using a simple scheme of tracking the neighbors' directions, defer their transmission toward the beams that could harm the ongoing communication. In this way, the proposed protocol takes advantage of the benefits of Directional transmissions as the increase of spatial reuse and of coverage range. Additionally, it reduces the hidden-terminal problem, as well as the deafness problem, two main factors for the decrease of the efficiency of Directional transmissions in ad hoc networks. The performance evaluation of the protocol shows that it offers a significant improvement in static, as well as mobile, scenarios, as compared to the performance of the proposed protocols that use omniDirectional or Directional transmissions.
Sangheon Pack - One of the best experts on this subject based on the ideXlab platform.
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Multiband Directional Neighbor Discovery in Self-Organized mmWave Ad Hoc Networks
IEEE Transactions on Vehicular Technology, 2015Co-Authors: Hyunhee Park, Yongsun Kim, Taewon Song, Sangheon PackAbstract:A 60-GHz radio is an attractive technology in wireless home networks because it can provide high data rate up to a few gigabits per second. A 60-GHz network generally uses Directional antennas and has a problem of neighbor discovery (ND), although it has an advantage of high data transmissions. In particular, if a Directional antenna is used in self-organized wireless ad hoc networks, the ND time and energy consumption can be significantly increased. To solve this problem, we propose a multiband Directional ND (MDND) scheme, in which management procedures are carried out by using the 2.4-GHz band with the omniDirectional antennas, whereas data transmissions are performed by using the 60-GHz band with Directional antennas. Analytical models on the ND time and energy consumption are also derived by considering assisted and beamforming periods in the ND procedure through the omniDirectional and Directional antennas. Performance evaluation results demonstrate that the proposed scheme outperforms comparative schemes that use only Directional beamforming in terms of the average ND time and energy consumption.
Mineo Takai - One of the best experts on this subject based on the ideXlab platform.
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Directional virtual carrier sensing for Directional antennas in mobile ad hoc networks
Mobile Ad Hoc Networking and Computing, 2002Co-Authors: Mineo Takai, Jay Martin, Rajive BagrodiaAbstract:This paper presents a new carrier sensing mechanism called DVCS (Directional Virtual Carrier Sensing) for wireless communication using Directional antennas. DVCS does not require specific antenna configurations or external devices. Instead it only needs information on AOA (Angle of Arrival) and antenna gain for each signal from the underlying physical device, both of which are commonly used for the adaptation of antenna pattern. DVCS also supports interoperability of Directional and omni-Directional antennas. In this study, the performance of DVCS for mobile ad hoc networks is evaluated using simulation with a realistic Directional antenna model and the full IP protocol stack. The experimental results showed that compared with omni-Directional communication, DVCS improved network capacity by a factor of 3 to 4 for a 100 node ad hoc network.
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MobiHoc - Directional virtual carrier sensing for Directional antennas in mobile ad hoc networks
Proceedings of the 3rd ACM international symposium on Mobile ad hoc networking & computing - MobiHoc '02, 2002Co-Authors: Mineo Takai, Jay Martin, Rajive BagrodiaAbstract:This paper presents a new carrier sensing mechanism called DVCS (Directional Virtual Carrier Sensing) for wireless communication using Directional antennas. DVCS does not require specific antenna configurations or external devices. Instead it only needs information on AOA (Angle of Arrival) and antenna gain for each signal from the underlying physical device, both of which are commonly used for the adaptation of antenna pattern. DVCS also supports interoperability of Directional and omni-Directional antennas. In this study, the performance of DVCS for mobile ad hoc networks is evaluated using simulation with a realistic Directional antenna model and the full IP protocol stack. The experimental results showed that compared with omni-Directional communication, DVCS improved network capacity by a factor of 3 to 4 for a 100 node ad hoc network.
