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    Please use this identifier to cite or link to this item: http://ir.lib.ksu.edu.tw/handle/987654321/6475

    Title: 以模糊回授控制模型分析並實現 IEEE 802.11e 媒體存取控制服務品質之增進(1/2)
    Analysis and Realization of IEEE 802.11e Medium Access Control (MAC) Quality of Service (QoS) Enhancement by Using Fuzzy Feedback Control Model
    Authors: 陳朝烈
    Keywords: 無線無基礎網路
    wireless ad-hoc networks
    cross-layer control
    Date: 2006-07-31
    Issue Date: 2009-12-30 14:39:48 (UTC+8)
    Abstract: 跨層設計對於無線無基礎式網路中進行多媒體串流時特別有效。然而,跨層的通訊協定介面並未標準化,也還有許多開放的空間可以研究。本計劃中我們提出了階層式的跨層控制(hierarchical cross-layer control,HCLC)模型,用以在無線網路上傳輸多媒體。觀念上來說通訊協定中上層形成一個控制器對於它的下層產生控制,而下層接收上層的控制當成它的參考輸入,並且同時對他的下一層也產生控制。因此,某一層的控制器對於其他層來說是透明的。藉由HCLC,除了要新增一些上下層溝通的機制之外傳統OSI 的協定架構並不會被破壞。對於無基礎網路上的多媒體串流物件,HCLC 控制器涵蓋了IEEE802.11e 的媒體存取(MAC)以及傳輸與應用層。MAC 的上層接收MAC 的存取延遲回授並計算新的參考輸入,也就是新的通訊規格(traffic specification, TSPEC)給MAC,MAC 調整延伸分散式通道存取(Enhanced Distributed Channel Access, EDCA)中退讓(backoff)機制參數,藉以調整radio rate 以符合video rate。分析與實驗顯示出所提出的HCLC 控制可以即時配置有效的頻寬,同時也保留了公平性,即使網路環境是多麼地未知難測與變化時亦然。
    Cross-layer designs for multimedia streaming over wireless ad-hoc networks are found that can gain better performance in many aspects. However, the cross-layer interfaces of protocol layers are still not standardized and many open issues are left. We propose a new hierarchical cross-layer control (HCLC) model for multimedia streaming over wireless networks. An upper layer forms a controller producing controls to its lower layers. A lower layer receive upper layers’ controls as its reference input command and produce its own control to next lower layers. Therefore, a layer controller is transparent to its lower and upper layer controllers. By HCLC, the conventional OSI protocol structure is not destroyed except including additional signaling schemes among controllers. For streaming multimedia objects over ad-hoc wireless networks, the controller comprises the IEEE 802.11e media access control (MAC) and the upper layers including the transport, and the application layers. The upper layers receive the MAC access delay feedback and calculate new reference goal as traffic specification (TSPEC) to the MAC layer. The MAC tunes the backoff parameters of the Enhanced Distributed Channel Access (EDCA) function to meet the dynamic TSPEC from upper layers. Analysis and experiments show that the proposed control provides real-time bandwidth allocation and at the same time preserves fairness no matter how the network state is uncertain and dynamic.
    Appears in Collections:[電子工程系所] 研究計畫

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