The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Tarek N. Saadawi - One of the best experts on this subject based on the ideXlab platform.
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Decoupled Multipath Structure for throughput enhancement in wireless mesh networks
IEEE Wireless Communications and Networking Conference 2006. WCNC 2006., 2006Co-Authors: Xuhui Hu, Tarek N. SaadawiAbstract:Multipath routing is typically utilized in wireless mesh networks for fault tolerance, throughput enhancement, and load balancing purposes. To achieve good route resilience and optimal end-to-end transmission performances, most Multipath routing algorithms tend to establish link-disjoint or node-disjoint paths with minimized path costs. Although multiple paths created by these algorithms do not share common links or nodes, they are usually located close to each other. If all these paths are activated simultaneously to boost end-to-end throughput, serious inter-path interferences will happen. In this paper, we first introduce an AODV-based decoupled Multipath routing protocol named AODV-DM. AODV-DM builds an insulating region around each established path to prevent new paths from being formed in the neighborhood of the established path. By this means, several "isolated" paths can be created and utilized for simultaneous data transmissions. We also present a novel destination-polling scheme to improve medium access efficiency in destination area, and at the same time alleviate the out-of-sequence problem caused by concurrent packet transmissions through multiple paths. By optimizing the functions crossing network and MAC layers, we are able to complete the design of an efficient Multipath Structure targeting at end-to-end throughput enhancement. Simulation results demonstrate that the decoupled Multipath Structure can achieve much higher throughput than single-path and coupled-path cases
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WCNC - Decoupled Multipath Structure for throughput enhancement in wireless mesh networks
IEEE Wireless Communications and Networking Conference 2006. WCNC 2006., 2006Co-Authors: Xuhui Hu, Tarek N. SaadawiAbstract:Multipath routing is typically utilized in wireless mesh networks for fault tolerance, throughput enhancement, and load balancing purposes. To achieve good route resilience and optimal end-to-end transmission performances, most Multipath routing algorithms tend to establish link-disjoint or node-disjoint paths with minimized path costs. Although multiple paths created by these algorithms do not share common links or nodes, they are usually located close to each other. If all these paths are activated simultaneously to boost end-to-end throughput, serious inter-path interferences will happen. In this paper, we first introduce an AODV-based decoupled Multipath routing protocol named AODV-DM. AODV-DM builds an insulating region around each established path to prevent new paths from being formed in the neighborhood of the established path. By this means, several "isolated" paths can be created and utilized for simultaneous data transmissions. We also present a novel destination-polling scheme to improve medium access efficiency in destination area, and at the same time alleviate the out-of-sequence problem caused by concurrent packet transmissions through multiple paths. By optimizing the functions crossing network and MAC layers, we are able to complete the design of an efficient Multipath Structure targeting at end-to-end throughput enhancement. Simulation results demonstrate that the decoupled Multipath Structure can achieve much higher throughput than single-path and coupled-path cases
Xuhui Hu - One of the best experts on this subject based on the ideXlab platform.
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an efficient Multipath Structure for concurrent data transport in wireless mesh networks
Computer Communications, 2007Co-Authors: Xuhui HuAbstract:Multipath routing is employed extensively in wireless mesh networks for fault tolerance, throughput enhancement, and load balancing purposes. Most existing Multipath routing methods tend to establish link-disjoint or node-disjoint paths with minimal path costs. As paths created by these methods are typically close to each other, they may cause serious inter-path interference when serving for concurrent data transmissions. In this paper, we first introduce an AODV-based decoupled Multipath routing protocol named AODV-DM. AODV-DM builds an insulating region around each established path to prevent new paths from being formed in the neighborhood of the established path. Multiple paths formed by this means are ''isolated'' from each other; thereby they are very suitable to serve for concurrent data transmissions. We also investigate the transport-layer route-coupling problem, and conclude that a path-aware SCTP scheme is a very good match to our AODV-DM protocol. The path-aware SCTP scheme enables the transport layer to make the most of the capacity provided by decoupled Multipath. We simulate the AODV-DM protocol and integrate it with the path-aware SCTP protocol. The simulation results demonstrate that AODV-DM, combined with the path-aware SCTP, significantly boosts end-to-end throughput of multihop data transmissions. This decoupled Multipath Structure is especially beneficial to concurrent transmissions of time-constraint data in wireless mesh networks.
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Decoupled Multipath Structure for throughput enhancement in wireless mesh networks
IEEE Wireless Communications and Networking Conference 2006. WCNC 2006., 2006Co-Authors: Xuhui Hu, Tarek N. SaadawiAbstract:Multipath routing is typically utilized in wireless mesh networks for fault tolerance, throughput enhancement, and load balancing purposes. To achieve good route resilience and optimal end-to-end transmission performances, most Multipath routing algorithms tend to establish link-disjoint or node-disjoint paths with minimized path costs. Although multiple paths created by these algorithms do not share common links or nodes, they are usually located close to each other. If all these paths are activated simultaneously to boost end-to-end throughput, serious inter-path interferences will happen. In this paper, we first introduce an AODV-based decoupled Multipath routing protocol named AODV-DM. AODV-DM builds an insulating region around each established path to prevent new paths from being formed in the neighborhood of the established path. By this means, several "isolated" paths can be created and utilized for simultaneous data transmissions. We also present a novel destination-polling scheme to improve medium access efficiency in destination area, and at the same time alleviate the out-of-sequence problem caused by concurrent packet transmissions through multiple paths. By optimizing the functions crossing network and MAC layers, we are able to complete the design of an efficient Multipath Structure targeting at end-to-end throughput enhancement. Simulation results demonstrate that the decoupled Multipath Structure can achieve much higher throughput than single-path and coupled-path cases
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WCNC - Decoupled Multipath Structure for throughput enhancement in wireless mesh networks
IEEE Wireless Communications and Networking Conference 2006. WCNC 2006., 2006Co-Authors: Xuhui Hu, Tarek N. SaadawiAbstract:Multipath routing is typically utilized in wireless mesh networks for fault tolerance, throughput enhancement, and load balancing purposes. To achieve good route resilience and optimal end-to-end transmission performances, most Multipath routing algorithms tend to establish link-disjoint or node-disjoint paths with minimized path costs. Although multiple paths created by these algorithms do not share common links or nodes, they are usually located close to each other. If all these paths are activated simultaneously to boost end-to-end throughput, serious inter-path interferences will happen. In this paper, we first introduce an AODV-based decoupled Multipath routing protocol named AODV-DM. AODV-DM builds an insulating region around each established path to prevent new paths from being formed in the neighborhood of the established path. By this means, several "isolated" paths can be created and utilized for simultaneous data transmissions. We also present a novel destination-polling scheme to improve medium access efficiency in destination area, and at the same time alleviate the out-of-sequence problem caused by concurrent packet transmissions through multiple paths. By optimizing the functions crossing network and MAC layers, we are able to complete the design of an efficient Multipath Structure targeting at end-to-end throughput enhancement. Simulation results demonstrate that the decoupled Multipath Structure can achieve much higher throughput than single-path and coupled-path cases
M.k. Tsatsanis - One of the best experts on this subject based on the ideXlab platform.
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Blind Adaptive Algorithms for Minimum Variance
2020Co-Authors: Zhengyuan Xu, M.k. TsatsanisAbstract:Constrained optimization methods have received considerable attention as a means to derive blind multiuser receivers with low complexity. The receiver's output variance is minimized subject to appropriate constraints which depend on the Multipath Structure of the signal of interest. When Multipath is present, the constraint equations can be written in parametric form, and the constraint parameters jointly optimized with the linear receiver's parameters. In this paper, we develop adaptive solutions for this joint, constrained optimization problem. Both stochastic gradient and recursive least-square-type algorithms are developed. The performance of the proposed methods is compared with other blind and trained methods and turns out to be close to the trained minimum mean-square-error receiver.
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Blind adaptive algorithms for minimum variance CDMA receivers
IEEE Transactions on Communications, 2001Co-Authors: Zhengyuan Xu, M.k. TsatsanisAbstract:Constrained optimization methods have received considerable attention as a means to derive blind multiuser receivers with low complexity. The receiver's output variance is minimized subject to appropriate constraints which depend on the Multipath Structure of the signal of interest. When Multipath is present, the constraint equations can be written in parametric form, and the constraint parameters jointly optimized with the linear receiver's parameters. We develop adaptive solutions for this joint, constrained optimization problem. Both stochastic gradient and recursive least-square-type algorithms are developed. The performance of the proposed methods is compared with other blind and trained methods and turns out to be close to the trained minimum mean-square-error receiver.
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Blind stochastic gradient methods for optimal minimum variance CDMA receivers
Conference Record of Thirty-Second Asilomar Conference on Signals Systems and Computers (Cat. No.98CH36284), 1998Co-Authors: Zhengyuan Xu, M.k. TsatsanisAbstract:Constrained optimization methods have received considerable attention as a means to derive blind multiuser receivers with low complexity. In this paper the receiver's output variance is minimized subject to appropriate constraints which depend on the Multipath Structure of the signal of interest. The constraint equations can be written in parametric form, and the constraint parameters jointly optimized with the linear receiver's parameters. We develop stochastic gradient based solutions for this joint, constrained optimization problem. Different variations of constrained LMS-type algorithms are presented and global convergence is established. The performance of the proposed methods is compared with other blind and trained methods. Moreover, the constraint parameters are observed to converge to the channel parameters of the user of interest at high SNR.
Gangqiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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ChinaCom (1) - Underwater Acoustic Channel Estimation Based on Signal Cancellation
Communications and Networking, 2020Co-Authors: Yangze Dong, Gangqiang Zhang, Junqing ZhangAbstract:Aiming at the requirement of underwater information security transmission, the security of encryption key generation and distribution in underwater acoustic communication is concerned. Key generation technology based on underwater acoustic channel (UAC) estimation can improve the security and real-time generation of encryption keys. In this paper, the idea of estimating the Multipath Structure of UAC is to retrieve the arrival signal by acquiring the parameters of larger energy Eigen-ray from real arrival signal, and to eliminate the arrival signal of larger energy Eigen-ray path from the real signal through signal cancellation, so as to eliminate the influence of side lobes of larger energy signal to arrival signals of other Eigen-ray path, to improve the estimation performance of Multipath Structure in underwater acoustic channel. The simulation and experimental results show that the improved algorithm can estimate the Multipath Structure of underwater acoustic channel more accurately and provide support for the subsequent underwater information security transmission.
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Exploiting joint sparsity for underwater acoustic MIMO communications
Applied Acoustics, 2017Co-Authors: Yuehai Zhou, Wei-hua Jiang, Feng Tong, Gangqiang ZhangAbstract:Abstract MIMO communication has been recognized as a potential solution for high speed underwater acoustic communication, which unfortunately encounters significant difficulties posed by simultaneous presence of Multipath and Co-channel interference (CoI). Sparsity contained in the Multipath Structure of underwater acoustic channels offers an effective way for improving channel estimation quality and thus enhancing the communication performance in the form of time reversal or channel estimation based equalization. However, for MIMO channels with extensive Multipath and CoI, the performance gain achieved by classic sparsity exploitation channel estimation methods such as orthogonal matching pursuit (OMP) is still not enough to yield satisfactory performance. Under quasi-stationary assumption, underwater acoustic channels of adjacent data blocks exhibit correlated Multipath Structure, namely, Multipath arrivals with similar time delay but different magnitude, which has not been exploited. In this paper, a joint sparse recovery approach is proposed to exploit the sparse correlation among adjacent data blocks to improve the performance of channel estimation. Under the framework of distributed compressed sensing (DCS), a joint sparse model which treats the Multipath arrivals as sparse solutions with common time support is adopted to derive a joint sparse recovery algorithm for efficient channel estimation, the results of which are used to initialize and periodly update a channel estimation based time reversal receiver. Finally, underwater MIMO communication experimental results obtained in a shallow water channel are provided to demonstrate the effectiveness of the proposed method, compared to the same type of receiver that do not exploit the joint sparse.
Hongbo Tian - One of the best experts on this subject based on the ideXlab platform.
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Channel estimation for spatially-correlated MIMO based on Multipath Structure estimation
2007 International Symposium on Communications and Information Technologies, 2007Co-Authors: Hongbo TianAbstract:We address pilot-aided channel estimation for a flat-fading spatially-correlated MIMO system, which employing Uniform Linear Arrays(ULA) on dual side and working in sparse scattering (Multipath) environment. In case of sparse scattering, channel matrix and spatial correlation of flat-fading MIMO systems are parameterized by Structure of Multipaths, which is represented as Direction of Arrivals(DOAs), Direction of Departures (DODs) and complex path fading of each path. Based on this and block-fading property of channel, we design a channel estimation method via estimating Multipath parameters using ESPRIT-like DOA-Matrix method which exploits shift-invariance property of ULA. The proposed method is able to obtain improved Mean-Square-Error performance than Least-Square method without prior information of spatial correlation.