感知無線電網路中分散式頻譜偵測與接取及其在小細胞網路之應用

Abstract

於本研究中，吾人分析感知無線電網路中分散式多通道頻譜偵測與取用問題。吾人首先將頻譜偵測與取用問題轉化成對於偵測時間與傳送功率之約束最佳化問題，並解出每個通道最佳的偵測時間與傳送功率。由於此方法之運算複雜度很高，吾人提出一個基於偵測門檻概念之低複雜度偵測與取用方法，並導出其解析數學形式。此外，吾人將偵測門檻概念之低複雜度偵測與取用方法應用於小細胞網路，並結合動態資料驅動應用系統(dynamic data driven applications systems ; DDDAS)的概念，提出一分散式基於流量之動態偵測與取用策略，以提高系統能量效率。最後，電腦模擬結果顯示出吾人提出的偵測與取用方法相較於傳統方法，於感知無線電網路能達到較佳的傳輸速率，於小細胞網路也能達到較佳的能量效率。

In this thesis, we analyze the distributed multi-channel spectrum sensing and access problem in cognitive radio network. The sensing and access problem is first formulated as a constrained optimization problem, and the optimal sensing time and transmit power are solved for the secondary users. To alleviate the computational complexity of the above scheme, we propose a low-complexity threshold-based scheme, and derive its analytical solution. Applying the concept of proposed threshold-based scheme and dynamic data driven applications systems (DDDAS), we propose a distributed traffic-aware distributed sensing and access scheme to enhance the system energy efficiency in small cell networks. Finally, computer simulation results show that the proposed schemes can achieve higher throughput and energy efficiency compared to prior benchmark schemes in cognitive radio network and small cell network, respectively.