在企業級的無線網路環境中需要多個無線基地台存取點提供許多使用者上網服務, 為了要讓使用者能夠使用較快的上網速度,需要部署許多的基地台服務人群,但是 在一個高密度的無線網路環境中多個AP會造成嚴重的訊號干擾(Interference),所 以調整AP的功率大小是一個重要的議題。無線軟體定義網路(SDN based Wireless Network)在近幾年已經成為企業級無線網路新穎的解決方案,其優勢在於無線軟體 定義網路中會有一個中央控制中心可以控管無線基地台存取點(Access Point)的功 率,AP及使用者的相關資訊能及時的通知中央控制中心然後即時的改善一些參數 的調控。
在這篇論文中,我們探討在高密度的無限軟體定義網路下,達成調整Wi-Fi AP的功率大小來使得整體使用者的網路傳輸吞吐量(throughput)最大化。我們利用 了SDN中央控制中心的優勢,設計了一個集中式的演算法求得網路傳輸最大化的功 率配置,並且使用NS3(Network Simulator)驗證演算法的效果,從模擬的結果可以 看出我們所提出的演算法對於分配給AP的功率配置能有效降低干擾,對網路傳輸 吞吐量也有良好的表現。

In a high density enterprises wireless networks, high interference resulting from the co-channel cells is the main challenge to be solved. Power level is one of the variable can be tuned to mitigate interference. The total throughput of clients is depend on the Bit-rate between the AP and the client. Adjust power level from AP will affect the Bit-rate to other transmission links. In this thesis, we introduced a SDN-based power adjustment algorithm to mitigate interference in such a high density enterprises wireless networks.
To the best of our knowledge, we are first to study the power adjustment problem in SDN-based WLANs. We implement the Algorithm through NS3 simulator and the result shows that in a dense network the proposed algorithm is greater than the commercial deployment of AP and the total throughput is close to the OPT of the wireless networks.

1 Introduction and Related Work 1
1.1 Introduction................................ 1
1.2 RelatedWork............................... 4
2.1 NetworkArchitecture........................... 7
2.2 ChannelModel .............................. 9
3 Power Adjustment............................10
3.1 ProblemandAlgorithm ......................... 10
4 Performance Evaluations...............15
4.1 BitRateTable .............................. 15
4.2 EvaluationforAPPowerAdjustment.................. 15
4.3 SimulationResult............................. 17
Conclusion and future works............... 19

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