458 research outputs found

    Workshop on real-time for multimedia (RTMM), Catania, Italy, June 29, 2004

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    A simulation study of video conferencing system over IEEE 802.11n Wireless LAN

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    Wireless local area network (WLAN) is the core of the classic wireless communications systems and owns the infrastructure which wide spreads in many regions in the world. IEEE 802.11n is an attractive standard of WLAN and offers a data capacity of the cell. This paper estimates the maximum limits of the IEEE 802.11n standard cell as a term of number of users which are successfully served by the cell in case of video conference application. The results shown that, the cell of 802.11n could serve about 9 users under the service of video conference in case of 20MHz channel bandwidth before congestion occurs while the 40MHz channel could support 18 users

    Multiprotocol control of networked home entertainment devices

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    Networks will soon connect a wide range of computing devices within the home. Amongst those devices will be home entertainment devices. Remote control over the network will be a key application for networked entertainment devices, and requires a protocol for communication understood by both controller and controlled device. Devices capable of communication using multiple control protocols will be compatible with a wider range of controllers than those which implement only one control protocol. This work examines home networks and a number of control protocols. The implementations of the UPnP and AV/C protocols for an AV receiver are described. The issues involved in the concurrent use of multiple control protocols to control a device are considered, possible methods of concurrent control discussed, and a solution which simulates virtual copies of the device is implemented and tested

    Enhancement of Adaptive Forward Error Correction Mechanism for Video Transmission Over Wireless Local Area Network

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    Video transmission over the wireless network faces many challenges. The most critical challenge is related to packet loss. To overcome the problem of packet loss, Forward Error Correction is used by adding extra packets known as redundant packet or parity packet. Currently, FEC mechanisms have been adopted together with Automatic Repeat reQuest (ARQ) mechanism to overcome packet losses and avoid network congestion in various wireless network conditions. The number of FEC packets need to be generated effectively because wireless network usually has varying network conditions. In the current Adaptive FEC mechanism, the FEC packets are decided by the average queue length and average packet retransmission times. The Adaptive FEC mechanisms have been proposed to suit the network condition by generating FEC packets adaptively in the wireless network. However, the current Adaptive FEC mechanism has some major drawbacks such as the reduction of recovery performance which injects too many excessive FEC packets into the network. This is not flexible enough to adapt with varying wireless network condition. Therefore, the enhancement of Adaptive FEC mechanism (AFEC) known as Enhanced Adaptive FEC (EnAFEC) has been proposed. The aim is to improve recovery performance on the current Adaptive FEC mechanism by injecting FEC packets dynamically based on varying wireless network conditions. The EnAFEC mechanism is implemented in the simulation environment using Network Simulator 2 (NS-2). Performance evaluations are also carried out. The EnAFEC was tested with the random uniform error model. The results from experiments and performance analyses showed that EnAFEC mechanism outperformed the other Adaptive FEC mechanism in terms of recovery efficiency. Based on the findings, the optimal amount of FEC generated by EnAFEC mechanism can recover high packet loss and produce good video quality
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