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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/60967


    Title: 正交分頻多工存取在不完美通道狀態資訊下之資源分配;Resource Allocation with Imperfect CSI in OFDMA Environments
    Authors: 何承翰;Ho,Cheng-han
    Contributors: 通訊工程學系
    Keywords: 正交分頻多工存取;資源分配;無妒忌;OFDMA;resource allocation;envy-free
    Date: 2013-07-03
    Issue Date: 2013-08-22 12:07:52 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 以往在正交分頻多工存取(orthogonal frequency division multiple access, OFDMA)環境下的資源分配(resource allocation)研究,大多假設可以獲得完美的通道狀態資訊(channel state information, CSI),然而由於存在通道估測誤差以及時間回覆延遲等原因,使得以上假設不符合實際情況,因此在不完美通道狀態資訊(imperfect CSI)下的資源分配演算法設計,在近年來獲得了較多的關注。本篇論文首先討論正交分頻多工存取環境,在完美通道狀態資訊下的Chunk 分配,接著將此技術應用於所提出之正交分頻多工存取環境,在不完美通道狀態資訊下的資源分配方式中,以簡化系統的運算次數。
    本文提出一種新的資源分配演算法,稱作無妒忌資源分配(envy-free resource allocation),此方法能夠降低使用者在正交分頻多工存取環境,因為資源分配不均而產生的妒忌行為。提出的演算法以最小化使用者彼此間分配到的平均資料率總和差異為目標,並確保每個分配的子載波能夠滿足位元錯誤率的限制條件。
    模擬結果顯示出,提出的演算法隨著可用來分配的Chunk 個數增加時,使用者彼此
    之間分配到的平均資料率總和差異數值也會逐漸變小,代表著使用者產生妒忌行為的可能性也越小。另外當可用來分配的Chunk 個數夠多時,兩個使用者在不同的可加性錯誤情形下的效能表現,也能夠接近兩個使用者在相同的可加性錯誤情形下的效能表現。
    The design of resource allocation in OFDMA environments have been assumed that perfect channel state information (CSI) can be estimated in previous researches. However, it is rarely possible to get perfect CSI due to channel estimation error and feedback delay. Hence,the algorithm to solve imperfect CSI draws much more attention. In order to reduce computation amount for system, we have discussed the chunk allocation technique in OFDMA environments with perfect CSI and combine this technique into our proposed scheme in OFDMA environments with imperfect CSI.
    In this thesis, we proposed a novel resource allocation algorithm called “envy-free resource allocation” which could reduce the envy behavior among users due to unequal allocated resources in OFDMA environments. The proposed scheme minimizes the total average rate difference between each pair of users, subject to average BER constraints for each allocated subcarrier.
    Simulation results show that, a larger allocated number of chunks could guarantee a smaller total average rate difference between users, resulting in a much smaller chance for users to envy each other. Furthermore, when the allocated chunk number is big enough, then the performance of users with unequal additive error is close to users with equal additive error.
    Appears in Collections:[通訊工程研究所] 博碩士論文

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