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標題: | 無線網路上應用網路編碼提升效能之研究 Network Coding based Performance Improvement in Wireless Networks |
作者: | Kun-Cheng Chung 鍾昆錚 |
指導教授: | 廖婉君(Wanjiun Liao) |
關鍵字: | 網路編碼,無線網路,效能提升, network coding,performance improvement,wireless network, |
出版年 : | 2016 |
學位: | 博士 |
摘要: | 近年來隨著無線裝置數量的增加,不僅是手機、筆電、平板以及諸多類型的無線穿戴裝置都被應用在無線網路上。這為無線網路帶來了非常強烈的挑戰。其中,網路編碼被證明是一個很有潛力能提升網路效能的技術。在這篇論文中,我們要探討的是,整合網路編碼到無線網路中會遇到的數個關鍵問題。在無線隨意網路中,我們考慮了高密度以及低密度環境中應用網路編碼的可能性。我們為這兩種狀況提出兩種有效的傳輸協定,此外,我們亦提出一個結合內部流通網路編碼、外部流通網路編碼以及機會路由的傳輸協定,並且驗證這三個協定都能解決網路固有的問題同時提升網路效能。
經過觀察,我們發現網路編碼最適合使用在機會路由上,因為在機會路由中引入網路編碼除了能提升網路效能以外還能大幅降低機會路由的設計複雜度。但是,這樣的組合需要付出冗餘傳輸的代價,特別是面對需求越來越高的網路,資源的使用效率是一個相當重要的問題。為克服此問題,我們為不同種類的機會路由提出了數學分析模型,分析在機會路由內成功傳輸所需的傳輸次數,並且推導出在無線隨意網路中使用隨機路由傳送資料的延遲。此模型可以容易的跟網路編碼結合,並且能為應用程式或是網路佈建業者的需求提供分析結果。同時,我們也探討不同密度對於機會路由傳輸效率的影響。 最後,我們在無線蜂巢網路上提出一個結合大規模多重輸入輸出以及網路編碼的方法來調和多樣性以及多工性,在此系統中最大化效用被建模為NP-Hard問題。我們提出了兩個低複雜度的演算法用來解決這個問題。此兩個演算法都在多項式時間內執行。模擬結果顯示我們提出的方法能有效的在大規模輸入輸出的環境下運用網路編碼增進無線蜂巢網路的效能。 綜觀以上問題,皆是在佈建次世代通訊系統整合網路編碼時會遇到的核心問題。我們相信本論文中提出的問題分析,以及提出的解決方案與實驗結果的觀察對於次世代通訊系統的佈建與規劃都能給予有價值的指引。 The exponential growth of the mobile devices market, not only smartphones but also tablets, laptops or wearables, poses a serious challenge for wireless communications. Network coding (NC), no matter inter-flow or intra-flow, is a promising solution for present and future networks as it has been shown to provide increased throughput, security and robustness for the transmission of data through the network. In this dissertation, we study how to exploit NC in different kind of wireless networks. Though NC has been proved to solve the bottleneck and packet loss problem, it still faces different challenges when using in different network. We first design two different mechanisms with intra-flow NC for network at low density and high density. Then we perform inter-flow NC on intra-flow NC based OR and show the throughput performance can be further improved through properly design. Though intra-flow NC based OR brings significant performance gains compare to traditional routing, the use of intra-flow NC based OR introduces a new challenge: How many coded packets should be transmitted? Therefore, in the second part of this dissertation, we propose analytical models for different kind of OR so that network managers can consider different aspects of the delay performance that can be achieved using OR. These models are useful in network planning, network deployment and decreasing energy consumption in wireless OR networks. The simulation results verified the accuracy and usability of these models. In the last part of this dissertation, a mechanism of using inter-flow NC with massive MIMO for wireless cellular network is proposed. This problem is modeled and proved to be NP-hard. We design two heuristic algorithms to solve the problem. The simulation result shows that the result of our algorithm is very close to optimal solution and can effectively exploit network coding on massive MIMO wireless cellular network for obtaining better performance. To summarize, this dissertation investigate how to employ NC in wireless networks and several issues are solved. We believe that our analysis and observation are valuable for the planning and designing of next generation network. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/78077 |
DOI: | 10.6342/NTU201602469 |
全文授權: | 有償授權 |
顯示於系所單位: | 電信工程學研究所 |
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