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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/44514

    Title: 基植於IEEE802.16 OFDMA網路上設計一考量下載資源管理之Burst調整、重疊與重排機制
    Other Titles: Burst Adjustment, Overlapping, and Relocation Schemes for Downlink Resource Allocation in IEEE 802.16 OFDMA Networks
    Authors: 林柏宇;Lin, Po-yu
    Contributors: 淡江大學資訊工程學系資訊網路與通訊碩士班
    石貴平;Shih, Kuei-ping
    Keywords: IEEE 802.16;正交分頻多工多重存取;下行資源配置
    Date: 2009
    Issue Date: 2010-03-16 10:33:39 (UTC+8)
    Abstract: 在IEEE 802.16 OFDMA-TDD系統下,DL-Burst排程機制是由多個矩形組成的二維空間。DL-burst是BS分配給SS的頻寬需求。在下行資源頻寬分配下,BS會因應每個SS在不同的Subchannel的CINR值選擇最適當的調變和編碼速率給每個SS。因此,為了追求更高throughput和capacity的系統下,BS會選擇最佳調變和編碼速率的Sub-channel給予每個SS。不當的DL-burst排程機制將會造成內部碎裂問題(Internal Fragmentation Problem, IFP)以及外部碎裂問題(External Fragmentation Problem, EFP)進而導致降低整體網路的效能。為了改善系統的效能,本論文針對已排程的Burst資源,提出Burst Adjustment, Overlapping, and Relocation(BAOR)機制,而在BRS機制中包含了Fragmentation Combination、Best Fit Relocation 和BOAS策略。BOS機制在可執行的情況下,可以讓內部碎裂slots重複地被使用。再經由BAS機制增加些微的MAP-overhead讓burst的配置型態有更多的配置種類,並隨著BRS機制的演算法,能因應配置環境做適當的變化調整burst,減少內部碎裂浪費和外部碎裂浪費,進而提升整體網路throughput。由實驗數據可以得知,本論文所提出的BAOR機制能改善已配置完成DL-Burst排程機制,可減少內部碎裂資源與外部碎裂資源浪費,提升網路資源利用率。
    Downlink Resource is two-dimensional space composed of many rectangular downlink burst traffics. A DL-burst traffic is the bandwidth allocation for SSs allocated by the BS. In downlink bandwidth allocation, BS would select the robust modulation to each SS according to the CINR of allocated sub-channel for each SS. With view to reaching to the High throughput and system capacity in IEEE 802.16 OFDMA system, the BS selects the sub-channel with the high modulation and the coding rate. However, unsuitable burst placement scheduling causes Internal Fragmentation Problem (IFP) and External Fragmentation Problem (EFP) and then it causes the system capacity down. In order to improving the system efficiency, we propose a Burst Adjustment, Overlapping, and Relocation Schemes (BAOR). In the availability of BOS, the unused slots of IFP can be reused. By using BAS, it makes the allocated rules of the burst traffics variable in OFDMA system and BRS will reduce the unused slots of the IFP and EFP and increase the throughput of the system. From Simulation result, (BAOR) Schemes can improve efficiently IFP and EFP, and increase the resource utilization and system throughput.
    Appears in Collections:[Graduate Institute & Department of Computer Science and Information Engineering] Thesis

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