臺灣大學: 電信工程學研究所廖婉君湯智翔Tang, Chih-HsiangChih-HsiangTang2013-03-272018-07-052013-03-272018-07-052010http://ntur.lib.ntu.edu.tw//handle/246246/253230隨著一般大眾對於無線上網日以繼增的頻寬要求，無線寬頻網路科技也隨之不斷的演進。從第三代行動網路和家用無線網路，一直到新一代的WiMAX和長程演進計畫LTE，甚至是目前還在制定中的4G標準，都希望能夠達到更快的傳輸速度以及更低的傳輸延遲。為了達到這麼快的傳輸速度，新一代的無線寬頻通訊有一些共同的無線通訊技術：正交分頻多工存取(OFDMA)、天線多輸入多輸出(MIMO)、多頻帶傳輸(multi-carrier)、支援中繼站(relay station)等等。 合作式無線通訊(Cooperative Communication)在近年來受到很多研究人員的矚目。在合作式無線通訊傳輸中，使用者之間互相合作以幫助對方傳送資料到目的端，透過這樣的機制，同一份資料透過兩個不同使用者幫忙傳輸，經過不同的路徑通道使得整體系統傳輸失敗的機率大幅下降，進而提升整體系統容量。另一方面，網路編碼(Network Coding)是另一項可以提升系統效能的無線技術。因為無線傳播的廣播特性，中繼點可以將收到的封包做互斥運算在傳送給兩端接收端。如此一來可以減少一次的傳輸，提升系統吞吐量。在本論文中我嘗試將合作式無線通訊和網路編碼結合起來，將這種合作式網路編碼運用在有中繼站的無線蜂巢網路中，希望結合兩者的優點能夠提升整體效能。 然而，在無線蜂巢網路中會遇到很多關鍵的問題，也是本論文需要解決的重點。在系統中的兩個使用者，該怎樣選擇中繼點來做合作式網路編碼？這中間會有怎樣的考量？我們該怎樣讓系統的整體效能達到最好？有鑑於這個問題跟無線網路資源分配問題息息相關，本論文將會將中繼點選擇問題結合上網路資源分配問題，定義問題核心範疇。除此之外，為瞭解決這個問題，將會提出一個有效的演算法來解決。最後會配合上電腦模擬結果來驗證演算法成效。希望透過這個論文來驗證合作式網路編碼在蜂巢是網路中的好處。The increasing rate on ubiquitous wireless broadband access drives the development of even better wireless communication technology. Both LTE-Advanced and 802.16m, potential candidates of so-called 4G standard, are capable of reaching over-the-air 1Gbps transmission rate which is required by IMT-Advanced. Although different in certain features, they both share many common key technologies, including OFDMA, MIMO, multi-carrier, relay support, etc. Relay operation is viewed as a highly efficient way to either increase cell coverage or enhance channel condition without deployment of a new BS. However, without proper setting and better way of transmission, relay operation might not be as good as expected. Cooperative communication is a promising communication technology developed in recent years. While it might not be possible for MS node to be equipped with several antennas, as MIMO requested, cooperative communication forms a virtual MIMO scheme through the cooperation with neighbor nodes. Theoretically proven, cooperative communication could not only increase system capacity, but enhance reliability. Network coding is another promising technology that attracts many researches. To encode receiving packets by XOR operation, network coding could largely reduce transmission time, so as to increase system throughput. In virtue of the above reasons, we try to combine cooperative communication with network coding and apply this new mechanism to cellular relay system. Cooperative network coding (CNC) for relay system generates challenging problems, among which relay selection might be the most important one. How to choose relay station (RS) to incorporate CNC remains a difficult problem. In the following article, we use relay station and RS alternately. Moreover, this work is highly associated with resource allocation problem. Hence, we propose a joint relay selection and resource allocation problem with precise formulation. Then, an algorithm is proposed to minimize the computation of original optimization problems. Finally, through computer simulation, results show that our work increase overall system capacity by a large degree.1244877 bytesapplication/pdfen-US合作式通訊網路編碼中繼點選擇中繼點資源分配正交分類多工存取802.16OFDMANetwork CodingCooperative CommunicationResource Allocationthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/253230/1/ntu-99-R97942035-1.pdf