動態通道選擇於感知無線電網路

近年來由於無線通訊應用的發展迅速，有限的無線頻譜資源逐漸不足，然而根據調查顯示在部分區域的多數頻帶使用率卻是相當低落，因此一個新的技術—感知無線電被提出以解決現在頻譜不足以及頻譜使用率不平均的問題。然而感知無線電網路中仍然存在許多問題。在本篇論文中，我們將專注於在多通道的感知無線電網路環境中感知無線電使用者如何能快速的找到可用通道來傳輸資料、感知無線電使用者礙於偵測技術的不足，不能正確的得知主要使用者的狀態（佔用、閒置），不但常會因為錯誤的偵測對主要使用者造成干擾，更無法改善頻譜使用率低落的問題，以及感知無線電使用者如何利用有限的能量得到最大的效益。在本篇論文中，第一章我們將對感知無線電網路做一個簡單的介紹。在第二章中，我們會利用部分可觀測馬可夫決策程序提出一個動態通道選擇機制，使得感知無線電使用者能夠快速的找到一個可用通道。在第三章中，我們會先簡單的分析感知無線電使用者對主要使用者造成干擾的狀況，然後提出一個機制，使得感知無線電使用者能夠在一個干擾限制下存取主要使用者的頻譜。在第四章中，我們會提出一個節能導向的動態通道選擇機制使得感知無線電使用者有效的利用能源達到最大的效益。

關鍵字

感知無線電；部分可觀測馬可夫決策程序；通道選擇；碰撞限制；能量節省

並列摘要

In the recent years, lots of studies indicated that the ineffective usage of licensed bands due to the static spectrum allocation. In order to solve this problem, cognitive radio is therefore proposed to dynamically exploit the primary frequency spectrums when the frequency spectrum is not occupied by a user. In this paper, we will focus on three problems, the first one is the delay time when secondary users searching an unoccupied channel, the second one is the probability of secondary user colliding with primary users, and the third one is the energy efficiency of secondary users. There are four chapters in this paper. In the first chapter, we will introduce the cognitive radio networks. In the second chapter, a dynamic channel selection using partially observation Markov decision process (POMDP) is proposed to find an unoccupied channel in minimum delay time. In the third chapter, we will analysis the situations of secondary users colliding with primary users. Then, we will propose an algorithm that constrains the collision probability. In the fourth chapter, we will propose an energy efficiency dynamic channel selection that minimizes the power secondary users wasting.

並列關鍵字

Cognitive Radio Networks ； Channel Selection ； Partially Observable Markov Decision Process ； Collision Constraint ； Power Saving

參考文獻

[3] Yang Xiao. Fei Hu, “Cognitive Radio Networks,” 2009.

[5] S. Haykin, ” Cognitive radio: brain-empowered wireless communications,” IEEE Journal on Selected Areas in Communications 23, pp. 201-220, Feb 2005.

[6] I.F. Akyildiz, W.-Y. Lee, M.C. Vuran and S. Mohanty,” Next generation/dynamic spectrum access/cognitive radio wireless networks: a survey,” Computer Networks 50, pp. 2127–2159, May 2006.

[7] W. S. Lovejoy, “A survey of algorithmic methods for partially observed markov decision processes,” Annals of Operations Research vol. 28, pp. 47-66, Dec 1991.

[8] R. D. Smallwood, E. J. Sondik, “The Optimal Control of Partially Observable Markov Processes over a Finite Horizon,” Operations Research, Oct, 1971.

國際替代計量

動態通道選擇於感知無線電網路

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