感知無線電中基於馬可夫模型之分散式優先使用者保護架構

近年來，由於無線技術的進步，在日常生活中有越來越多的無線設備和基地台架設，像是無線都會網路、無線區域網路、以及無線個人網路。這些無線網路系統必須佔用部分頻段，隨著越來越多無線標準的提出、運作，可用的無線頻譜也就越來越珍貴。然而研究顯示出頻帶的使用情形極度不平衡。針對這樣的問題，在1999年提出了感知無線電，感知無線電是一種有智慧的通訊系統，它可以察覺周遭環境變化，並從中學習，進而調整內部參數設定，做出最佳決定。這篇論文基於感知無線電的理論，提出一種在無線網路(802.11)架構下，保證優先使用者資料傳輸的機制，這個機制保證優先使用者和感知無線電使用者共存的情形下，感知無線電使用者的資料傳輸將會被限制以達到保證優先使用者的傳送資料不會受到感知無線電使用者的影響。我們使用馬可夫模型分析了在優先使用者傳輸未達到飽和狀態以及感知無線電使用者傳輸已達飽和狀態下，優先使用者的資料傳送量與感知無線電使用者的傳送參數的關連性，藉由這個關連性，我們可以找出最佳的傳輸參數設定以保障優先使用者的資料傳輸。我們透過網路模擬器的實驗來驗證我們提出的模型，此外，我們也利用模樣測試來證明我們提出的演算法表現良好。

關鍵字

感知無線電,保護優先使用者

並列摘要

In recent years, with wireless technologies advanced, there are more and more wireless devices and base stations deployment. These wireless systems must occupy some frequency bands. As a result, with more and more wireless standards released and implemented frequency spectrum is getting treasurable. Although frequency spectrum exhibits scarcity, research shows that spectrum is inefficiently and unbalanced utilized. The idea of cognitive radio was proposed in 1999 by Joseph Mitola to efficiently utilized the unused frequency spectrum and increase overall utilization. It is defined as an intelligent wireless system that is aware of it surrounding environment and learns from it to adapt its internal parameters in realtime. Based on the concept of cognitive radio, we propose "Markov-based Primary User Protection" in 802.11 environment. This scheme addresses the coexistence of primary users and cognitive radio users and guarantees the transmission of primary users will not be affected by cognitive radio users. At the same time, cognitive radio users can maximize their traffic to efficiently utilized the available channel resources. We first analyze the non-saturation Markov model of primary user as well as saturation Markov model of cognitive radio user. Combining two models together, we find out the relationship between current load of primary users and the optimal transmission parameter setting that can guarantee the usage of primary users. We validate our model by comparing the calculation yielded by the model and the results of simulation. In addition, we also verify our proposed algorithm behaves well through simulations.

並列關鍵字

Cognitive Radio, Primary User Protection

參考文獻

[1] Joseph Motila III, and Gerald Q. Maguire, Cognitive Radio: Making Software Radios More Personal, IEEE Personal Communications, vol. 6, pp. 13-18, 1999

[2] Simon Haykin, Cognitive Radio: Brain-Empowered Wireless Communications, IEEE Journal Selected Areas Communications, vol. 23, pp. 201-220, 2005

[3] Zhi Tian, Georgios B. Giannakis, A Wavelet Approach to Wideband Spectrum Sensing for Cognitive Radios, Cognitive Radio Oriented Wireless Networks and Communications, 2006

[4] M. A. Haleenm, R. Chandramouli, Adaptive stochastic iterative rate selection for wireless channels, IEEE Communications Letters, vol 8, pp. 292-294, 2004

[5] J. Neel, R. M. Buehrer, J. H. Reed, R. P. Gilles, Convergence of Cognitive Radio Networks, IEEE Wireless Communications and Networking Conference, pp. 2250-2255, Vol 4, 2004

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感知無線電中基於馬可夫模型之分散式優先使用者保護架構

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