DCF傳輸MPEG-4視頻流的研究
Study on Transmitting MPEG-4 Video Stream in WLAN
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摘要: IEEE 802.11無(wú)線局域網(wǎng)的基本接入方式是分布式協(xié)調(diào)功能(DCF)。當(dāng)無(wú)線局域網(wǎng)中的負(fù)載變大時(shí),采用DCF的站點(diǎn)可能在成功發(fā)送之前需要延遲幾秒以上。這將嚴(yán)重影響MPEG-4視頻流等實(shí)時(shí)應(yīng)用的性能。該文針對(duì)實(shí)時(shí)應(yīng)用提出了一種DCF的改進(jìn)機(jī)制L-DCF,并介紹了在L-DCF下如何傳輸MPEG-4視頻流。仿真結(jié)果表明,與DCF相比,采用L-DCF的MPEG-4視頻流將經(jīng)歷較少的時(shí)延和抖動(dòng),同時(shí)又具有與采用DCF時(shí)相同的吞吐量與公平性,因此能夠獲得更好的播放質(zhì)量。Abstract: The basis of IEEE 802.11 wireless LAN Medium Access Control (MAC) is Distributed Coordination Function (DCF), When network load in WLAN is moderate or even higher, with DCF a station may need to defer several seconds before successful transmission. This will degrade the performance of real time applications such as MPEG-4 video stream. This paper proposes L-DCF, which is suit for real time applications, and presents mechanism for transmitting MPEG-4 video stream with L-DCF. Simulations show that this mechanism provides much less delay and jitter while obtains the same goodput and fairness.
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