14 research outputs found

    P2ProxyLite: effective video streaming in wireless ad-hoc networks

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    Abstract-Video streaming over wireless connections remains a challenge today: even when data link and transport layer protocols are tuned to avoid retransmissions and thus reduce the delay and the used bandwidth, the impact on the perceived video quality of imperfect and band-limited radio channels is not negligible. This phenomenon is even more pronounced in multi-hop ad-hoc networks, where the received video quality is further reduced by a cascade of wireless transmissions causing additional delay, losses and errors. We propose in this work to enhance video streaming performance in ad-hoc networks by introducing in mobile nodes an improved frame treatment at the Data Link layer, associated to caching capabilities at the transport layer. This approach allows, on the one side, the forwarding of multimedia packets even in case of residual bit errors, which can be tolerated by robust video decoders, and, on the other side, a path reduction when multiple users are interested in the same content

    Controlling Joint Optimization of Wireless Video Transmission: the PHOENIX Basic Demonstration Platform

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    A global approach for realistic network-aware joint source and channel system optimization for wireless video transmission is described in this paper. After a description of the information to be exchanged among the system component blocks, the concept of "JSCC/D controllers" is introduced and the implementation of the first "basic chain" demonstrator realized in the framework of the PHOENIX project is described. Simulation results obtained with such first software demonstration platform confirm the validity of the described approach

    JPEG 2000 backward compatible error protection with Reed-Solomon codes

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    OMNeT++-Based Cross-Layer Simulator for Content Transmission over Wireless Ad Hoc Networks

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    Flexbility and deployment simplicity are among the numerous advantages of wireless links when compared to standard wired communications. However, challenges do remain high for wireless communications, in particular due to the wireless medium inherent unreliability, and to the desired flexibility, which entails complex protocol procedures. In that context simulation is an important tool to understand and design the protocols that manage the wireless networks. This paper introduces a new simulation framework based on the OMNeT++ simulator whose goal is to enable the study of data and multimedia content transmission over hybrid wired/wireless ad hoc networks, as well as the design of innovative radio access schemes. To achieve this goal, the complete protocol stack from the application to the physical layer is simulated, and the real bits and bytes of the messages transferred on the radio channel are exchanged. To ensure that this framework is reusable and extensible in future studies and projects, a modular software and protocol architecture has been defined. Although still in progress, our work has already provided some valuable results concerning cross layer HARQ/MAC protocol performance and video transmission over the wireless channel, as illustrated by results examples.</p
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