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ABSTRACT: Cognitive Radio (CR) technologies have been proposed as a promising solution to improve connectivity, self-adaptability, and efficiency of spectrum usage by using dynamic spectrum resource management. When used in multimedia applications in wireless networks, the end-to-end user-perceived video quality experienced by secondary users is a very important performance metric to evaluate the effectiveness of CR technologies. However, most of the current research activities consider only spectrum utilization and effectiveness, ignoring the system performance of upper layers. In this paper, we propose an end-to-end system to optimize the user-perceived video quality at the receiver end under the constraint of packet delay bound in cognitive wireless networks. By mathematically formulating the design objective and the design constraint, the impact of inextricably interrelated system parameters residing in different network layers are jointly considered and optimized in a holistic way to achieve the best-possible user-perceived video quality for secondary users. Further, we formulate the problem into a MIN-MAX problem, which is then solved by using dynamic programming. The performance enhancement by using the proposed system is demonstrated through extensive experiments based on H.264/AVC.
INFOCOM IEEE Conference on Computer Communications Workshops , 2010; 04/2010
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ABSTRACT: 3GPP long term evolution is one of the major steps in mobile communication to enhance the user experience for next-generation mobile broadband networks. In LTE, orthogonal frequency-division multiple access is adopted in the downlink of its E-UTRA air interface. Although cross-layer techniques have been widely adopted in literature for dynamic resource allocation to maximize data rate in OFDMA wireless networks, application-oriented quality of service for video delivery, such as delay constraint and video distortion, have been largely ignored. However, for wireless video delivery in LTE, especially delay-bounded real-time video streaming, higher data rate could lead to higher packet loss rate, thus degrading the user-perceived video quality. In this article we present a new QoS-aware LTE OFDMA scheduling algorithm for wireless real-time video delivery over the downlink of LTE cellular networks to achieve the best user-perceived video quality under the given application delay constraint. In the proposed approach, system throughput, application QoS constraints, and scheduling fairness are jointly integrated into a cross-layer design framework to dynamically perform radio resource allocation for multiple users, and to effectively choose the optimal system parameters such as modulation and coding scheme and video encoding parameters to adapt to the varying channel quality of each resource block. Experimental results have shown significant performance enhancement of the proposed system.
IEEE Communications Magazine 03/2010; · 3.79 Impact Factor
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Proceedings of the Global Communications Conference, 2010. GLOBECOM 2010, 6-10 December 2010, Miami, Florida, USA; 01/2010
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IEEE Communications Magazine. 01/2010; 48:102-109.
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J. Visual Communication and Image Representation. 01/2010; 21:98-106.
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ABSTRACT: As a TCP-Friendly Rate Control protocol on the basis of TCP Reno's throughput equation, TFRC is designed to provide optimal service for unicast multimedia delivery over the wired Internet networks. However, when used in wireless environment, it suffers significant performance degradation. Most of the current research on this issue only focuses on the TFRC protocol itself, ignoring tightly-coupled relation between the transport layer and other network layers. In this paper, we propose a new approach to address this problem, integrating TFRC with application layer and physical layer to form a holistic design for real-time video streaming over wireless multi-hop mesh networks. The goal of the proposed approach is to achieve the best user-perceived video quality by jointly optimizing system parameters residing in different network layers, including the real-time video coding parameters at the application layer, the packet sending rate at the transport layer, and the modulation and coding scheme at the physical layer. The problem is formulated and solved as to find the optimal combination of parameters to minimize the end-to-end expected video distortion constrained by a given video playback delay. Experimental results have validated 2-4 dB PSNR gain achieved by the proposed approach in wireless multi-hop mesh networks.
Communications, 2009. ICC '09. IEEE International Conference on; 07/2009
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ABSTRACT: This paper addresses cooperative video summary delivery over wireless networks which inherits both advantages from cooperative communication and from video summarization. In this work, a novel decode-process-and-forward (DPF) scheme is proposed for video summary transmission, where a relay node with video processing capability is involved to generate a concise version of the summary frame, called summary of summary (SoS). The SoS information is effectively consumed by the destination side to enhance its error concealment capability, leading to an improved video reconstruction quality. This paper proposes a generic cross-layer optimization framework for cooperative video summary transmission, which jointly considers the source coding, relay processing parameters, power allocation, and error concealment strategy to achieve the best video quality. The problem is solved by using Lagrangian relaxation and dynamic programming (DP). Experimental results show that the proposed scheme significantly outperforms the direct transmission scheme, the multipath scheme, and the decode-and-forward transmission scheme by up to 25%.
Sarnoff Symposium, 2009. SARNOFF '09. IEEE; 05/2009
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ABSTRACT: Rate control is an important issue in video streaming applications. The most popular rate control scheme over wired networks is TCP-Friendly Rate Control (TFRC), which is designed to provide optimal transport service for unicast multimedia delivery based on the TCP Reno’s throughput equation. It assumes perfect link quality, treating network congestion as the only reason for packet losses. Therefore, when used in wireless environment, it suffers significant performance degradation because of packet losses arising from time-varying link quality. Most current research focuses on enhancing the TFRC protocol itself, ignoring the tightly coupled relation between the transport layer and other network layers. In this paper, we propose a new approach to address this problem, integrating TFRC with the application layer and the physical layer to form a holistic design for real-time video streaming over wireless multi-hop networks. The proposed approach can achieve the best user-perceived video quality by jointly optimizing system parameters residing in different network layers, including real-time video coding parameters at the application layer, packet sending rate at the transport layer, and modulation and coding scheme at the physical layer. The problem is formulated and solved as to find the optimal combination of parameters to minimize the end-to-end expected video distortion constrained by a given video playback delay, or to minimize the video playback delay constrained by a given end-to-end video distortion. Experimental results have validated 2–4 dB PSNR performance gain of the proposed approach in wireless multi-hop networks by using H.264/AVC and NS-2.
Journal of Visual Communication and Image Representation.
