The Experts below are selected from a list of 258414 Experts worldwide ranked by ideXlab platform
Georgios B Giannakis - One of the best experts on this subject based on the ideXlab platform.
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advances in spectrum sensing and cross Layer Design for cognitive radio networks
Academic Press Library in Signal Processing, 2014Co-Authors: Seungjun Kim, Ketan Rajawat, Emiliano Dallanese, Juan Andres Bazerque, Georgios B GiannakisAbstract:Abstract Spectrum sensing is the key task for cognitive radio (CR) networks with significant challenges that have attracted a flux of research and innovation in recent years. Various signal processing, learning and optimization techniques have been employed to tackle different aspects. In this paper, progresses made in this area are reviewed with emphasis on cross-Layer Design issues. The recent spectrum cartography techniques that capture the spatio-temporal RF environment in which the CRs operate is described in detail for physical Layer sensing. MAC Layer issues of scheduling the sensing operation based on the observation history are also outlined. The trade-off between sensing accuracy and the system-wide objective is highlighted in the context of sequential sensing schemes. The cross-Layer benefit of rich cognition modalities toward network-wide performance is illustrated, and promising research directions are pointed out.
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cross Layer Design of coded multicast for wireless random access networks
IEEE Journal on Selected Areas in Communications, 2011Co-Authors: Ketan Rajawat, Nikolaos Gatsis, Georgios B GiannakisAbstract:Joint optimization of network coding and Aloha-based medium access control (MAC) for multi-hop wireless networks is considered. The multicast throughput with a power consumption-related penalty is maximized subject to flow conservation and MAC achievable rate constraints to obtain the optimal transmission probabilities. The relevant optimization problem is inherently non-convex and hence difficult to solve even in a centralized manner. A successive convex approximation technique is employed to obtain a Karush-Kuhn-Tucker solution. A separable problem structure is obtained and the dual decomposition technique is adopted to develop a distributed solution. The algorithm is thus applicable to large networks, and amenable to online implementation. Numerical tests verify performance and complexity advantages of the proposed approach over existing Designs. A network simulation with implementation of random linear network coding shows performance very close to the one theoretically Designed.
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cross Layer Design of coded multicast for wireless random access networks
Conference on Information Sciences and Systems, 2011Co-Authors: Ketan Rajawat, Nikolaos Gatsis, Georgios B GiannakisAbstract:Joint optimization of network coding and Aloha-based medium access control (MAC) for multi-hop wireless networks is considered. The multicast throughput is maximized subject to flow conservation and MAC achievable rate constraints to obtain the optimal transmission probabilities. The resultant optimization problem is inherently non-convex and hence difficult to solve even in a centralized manner. A successive convex approximation technique is employed to obtain a Karush-Kuhn-Tucker solution. A separable problem structure is obtained and the dual decomposition technique is adopted to develop a distributed solution. The algorithm is thus applicable to large networks, and amenable to online implementation. Numerical tests verify performance and complexity advantages of the proposed approach over existing Designs.
Dongman Lee - One of the best experts on this subject based on the ideXlab platform.
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a fine grain partial mac virtualization to support cross Layer Design in wireless ad hoc networks
Local Computer Networks, 2014Co-Authors: Seon Yeong Han, Byoungheon Shin, Dongman LeeAbstract:Cross Layer approach is a promising technology to satisfy applications' fastidious requirements and maximize the wireless channel usage in wireless ad hoc networks. Existing cross Layer architecture either adopts a specific MAC for an application type or does not change the MAC behavior because the MAC is commonly used for all types of applications in a node. MAC virtualization is an appropriate method to associate the MAC behavior with a specific application's requirement without impacting on other types of application. In this paper, we propose a partial MAC virtualization to support cross Layer Design in wireless ad hoc networks. In the proposed scheme, a MAC scheme is divided into a set of controllable condition variables and common MAC executor. A MAC control manager generates a virtual MAC with a set of controllable condition variables and related state variables. This paper also proposes an interface through which an application or an agent of the application can control the MAC for its own purpose, which allows a cross-Layer mechanism for each application in a node. We show the feasibility of the proposed scheme by an example and experiments.
Yaqin Zhang - One of the best experts on this subject based on the ideXlab platform.
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cross Layer Design for qos support in multihop wireless networks
Proceedings of the IEEE, 2008Co-Authors: Qian Zhang, Yaqin ZhangAbstract:Due to such features as low cost, ease of deployment, increased coverage, and enhanced capacity, multihop wireless networks such as ad hoc networks, mesh networks, and sensor networks that form the network in a self-organized manner without relying on fixed infrastructure is touted as the new frontier of wireless networking. Providing efficient quality of service (QoS) support is essential for such networks, as they need to deliver real-time services like video, audio, and voice over IP besides the traditional data service. Various solutions have been proposed to provide soft QoS over multihop wireless networks from different Layers in the network protocol stack. However, the Layered concept was primarily created for wired networks, and multihop wireless networks oppose strict Layered Design because of their dynamic nature, infrastructureless architecture, and time-varying unstable links and topology. The concept of cross-Layer Design is based on architecture where different Layers can exchange information in order to improve the overall network performance. Promising results achieved by cross-Layer optimizations initiated significant research activity in this area. This paper aims to review the present study on the cross-Layer paradigm for QoS support in multihop wireless networks. Several examples of evolutionary and revolutionary cross-Layer approaches are presented in detail. Realizing the new trends for wireless networking, such as cooperative communication and networking, opportunistic transmission, real system performance evaluation, etc., several open issues related to cross-Layer Design for QoS support over multihop wireless networks are also discussed in the paper.
Fausto Vieira - One of the best experts on this subject based on the ideXlab platform.
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dvb s2 full cross Layer Design for qos provision
IEEE Communications Magazine, 2012Co-Authors: Angeles Vazquez M Castro, Fausto VieiraAbstract:The second generation of the Digital Video Broadcasting standard for Satellite transmission, DVB-S2, is the evolution of the highly successful DVB-S satellite distribution technology. DVB-S2 has benefited from the latest progress in channel coding and modulation such as Low Density Parity Check Codes and higher order constellations to achieve performance that approaches Shannon?s theoretical limit. We present a cross-Layer Design for Quality-of-Service (QoS) provision of interactive services, which is not specified in the standard. Our cross-Layer approach exploits the satellite channel characteristics of space-time correlation via a cross-Layer queueing architecture and an adaptive cross-Layer scheduling policy. We show that our approach not only allows system load control but also rate adaptation to channel conditions and traffic demands on the coverage area. We also present the extension of our cross-Layer Design for mobile gateways focusing on the railway scenario. We illustrate the trade-off between system-wide and individual throughput by means of simulation, and that this trade-off could be a key metric in measuring the service level of DVB-S2 Broadband Service.
A Jayasuriya - One of the best experts on this subject based on the ideXlab platform.
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new cross Layer Design approach to ad hoc networks under rayleigh fading
IEEE Journal on Selected Areas in Communications, 2005Co-Authors: Peter P Pham, Sylvie Perreau, A JayasuriyaAbstract:We propose a new cross-Layer Design employing the predictability of Rayleigh channels to improve the performance of ad hoc networks. In addition, we propose a Markov model for Rayleigh channels and an innovative Markov model for IEEE 802.11 distributed coordination function. By combining these two models, we derive the theoretical expressions for network throughput, packet processing rate, packet loss probability, and average packet delay under Rayleigh channels. The simulation of the proposed cross-Layer Design is also carried out. It is shown that the new approach improves the network throughput, reduces unnecessary packet transmissions and therefore reduces packets lost. We also show that there is a close match between the analytical and the simulation results which confirms the validity of the analytical models.
