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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/8184


    Title: 正交分頻多重接取系統下之跨層式排程及資源分配演算法設計;A Cross Layer Scheduling and Resource Allocation Algorithm for OFDMA Wireless Networks
    Authors: 林瑤亭;Iao-Tin Lin
    Contributors: 通訊工程研究所
    Keywords: 跨層式排程及資源分配演算法;排程演算法;Wimax;服務質量;Cross layer scheduling algorithm;Scheduling;Wimax;Qos
    Date: 2007-07-05
    Issue Date: 2009-09-22 11:20:24 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 在本文中,我們討論兩個主題。第一個部份,我們提出了一個階層式排程演算法設計。IEEE 802.16的標準提供了四種不同的服務,分別是非請求的頻寬分配(UGS)、即時輪詢服務(rtPS)、非即時輪詢服務(nrtPS)、盡力傳送(BE)。每個服務的封包傳輸優先權皆有不同的限制。在排程演算法中,不僅根據媒體存取層(MAC layer)不同連線的服務質量所要求的保證傳輸頻寬和最大延遲時間來設計排程的方式,其中我們計算出每個框架(frame)中不同連線需要傳輸的資料量,藉以選擇使用者給實體層做傳遞之用;同時,也在排程演算法中加入不同用戶的實體層通道狀況。如此,媒體存取層在選擇使用者時,同時可以顧及服務質量和用戶的通道狀況,於是整個系統可以用此達到最好的傳輸效能和服務要求。這個演算法跟近兩年發表過的三個排程演算法做比較,在模擬結果可以看出我們提出的演算法效能較好。第二個部份,我們計算出分配子通道的最佳解,利用這樣的最佳解設計出演算法,藉由這樣的演算法,我們可以根據媒體存取層所選擇的用戶限制下,達到最高的資料傳輸量。結合這兩個部份,於是我們的演算法可以在滿足媒體存取層的不同傳輸要求下,又能提高整體的總傳輸速率,由我們的模擬繪圖可以證明我們的設計確實達到我們所想要的結果。 As multimedia communications develop rapidly in the recent years, in order to maximize the capacity of wireless networks, scheduling plays an important role in supplying quality of service (QoS) requirements to broadband wireless communications. The IEEE 802.16 standard provides four different scheduling services: Unsolicited Grant Service (UGS), real-time Polling Service (rtPS), non-real-time Polling Service (nrtPS), and Best Effort (BE). In this paper, we formulate the optimal problem by maximizing the average utility function of all active users and then propose a cross-layer algorithm to achieve the higher throughput by allocating resources dynamically. Our scheme is aimed at designing jointly dynamical subchannel assignment (DSA)and capacity planning (CP) solutions. The simulation focuses on IEEE 802.16 wireless systems working in Orthogonal Frequency Division Multiple Accesses (OFDMA) and Point-to-Multipoint (PMP) mode, with one single cell serving many Mobile Stations (MSs) in downlink transmission. Finally, the numerical result shows that the cross-layer algorithm approaches a higher throughput and improves extremely the performance of BE and nrtPS services while supporting the quality of rtPS services at acceptable levels.
    Appears in Collections:[通訊工程研究所] 博碩士論文

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