- 學位論文
方向性天線用於頻譜重用之新細胞結構
A New Cell Structure Based on Directional Antennas and the Frequency Allocation Scheme
摘要
在本論文中，我們提出一種建置在正交分頻多工存取技術的新細胞架構，主要能減少OFDMA網路細胞間的頻率干擾，增加頻率重用度，進而提升邊緣用戶可用頻寬。除此之外，此架構也能降低天線的傳輸功率，同時提高整體細胞的容量。 此方法中有幾個重點。首先，我們使用狹窄波束型方向性天線放置在細胞的六個角落，配合波束成形技術來改善扇形區的收訊，不僅可以降低天線的傳輸功率，增加天線數量更能使整體細胞的傳輸量增加。第二，在軟性頻率重用的機制裡，分配頻段提升頻譜使用率，以增加邊緣用戶能夠使用的頻寬。我們結合這兩種技術的優點，讓正交分頻多工存取通訊系統內任何地方的用戶都能獲得高品質的服務 本篇論文提出方法的有下列幾點貢獻： 1.降低系統傳輸功率，降低細胞間的干擾 2.提高頻譜使用率，增加邊緣用戶能夠使用的最高頻寬 我們相信本論文的研究結果能夠使細胞內的用戶獲得高品質的服務，在OFMDA蜂巢網路細胞間的干擾降低研究上有很大的幫助。
並列摘要
In this thesis, we build a new cell structure based on the Directional Antenna and the Radial Frequency Reuse (RFR) Scheme for the Orthogonal Frequency Division Multiple Access (OFDMA) technology. It can improve the problem of inter cell interference (ICI) among adjacent cells of OFDMA and increase the frequency reuse rate to raise the available bandwidth of cell edge users (CEUs). Otherwise, it can also reduce the transmission power and raise capacity of cells. There are several essentials in our new cell structure. At first, we put NTBC type of direction antennas with Beam Forming (BF) at the each vertex of the hexagonal cell. The placement can not only improve signals of CEUs but also raise the throughput of cells. Second, we use the radial frequency allocation to enhance the spectrum efficiency and increase the available bandwidth of CEUs. It will make users everywhere in a OFDMA communication network to obtain high quality services by the advantages combination of both technology. The contributions of our research are as follows: (1) Lower the transmission power strength and decrease ICI. (2) Increase frequency efficiency to increase available bandwidth for CEUs. These mechanisms can make cell users to obtain high quality services. The research results of our thesis will be very helpful for the ICI mitigation in OFDMA cellular networks.