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研究生： 陳政偉
Chen, Cheng-Wei
論文名稱： 上行多重輸入多重輸出感知無線電系統中干擾減輕排程器之研究
Interference Mitigation Schedulers for the Uplink MIMO Cognitive Radios
指導教授： 張志文
Chang, Chih-Wen
學位類別： 碩士
Master
系所名稱： 電機資訊學院 - 電腦與通信工程研究所
Institute of Computer & Communication Engineering
論文出版年： 2009
畢業學年度： 97
語文別： 英文
論文頁數： 53
中文關鍵詞： 感知無線電 、排程 、奇異值分解 、容量增益 、干擾減輕 、公平性
外文關鍵詞： Scheduling, Singular value decomposition, Capacity gain, Interference mitigation, Fairness index, Cognitive radio
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    • 感知無線電(Cognitive radio)系統的基本傳輸準則在於其對主要使用者(Primary user)過度干擾之限制的同時提升頻譜利用效率(Spectrum efficiency)。因此，感知無線電系統排程器(Scheduler)應對可遵守此準則下之感知無線電系統用戶妥善分配無線電系統資源。為了實現此準則，在本文中，我們設計幾個排程通用函式(Scheduling utility functions)作為其對主要使用者干擾效應之指標。並將排程通用函式併入傳統排程器，以達到避免過度干擾主要使用者之成效。然而，為了進一步提高系統容量，感知無線電用戶使用奇異值分解(Singular value decomposition)多重輸入多重輸出(Multiple input multiple output)方案進行資料傳輸。經由模擬結果的呈現，我們證明本文所提的干擾減輕排程器可有效減輕對主要使用者之干擾。此外，經由良好的排程通用函式設計，最大速率排程器(Max-rate)可以接近比例式公平(Proportional fair)排程器於公平性(Fairness)之表現。

    The rule of thumb of the cognitive radio (CR) systems is to enhance the spectrum efficiency without producing excessive interference to the primary users (PUs). Thus, in principle, a CR scheduler should be regulated to allocate the radio resources to the CR users who can follow this rule. To make this rule tractable, in this paper, we design several scheduling utility functions (SUFs) to characterize the interference to the PUs. Next, the SUFs are incorporated into the conventional schedulers to avoid the excessive interference to the PUs. In this way, the CR schedulers can stick by the aforementioned rule of thumb. Moreover, to further increase the system capacity, the singular value decomposition (SVD) multiple-input-multiple-output (MIMO) transmission scheme is adopted for the CR users. Through the simulation results, we prove the effectiveness of the proposed schedulers for the CR systems in terms of the system capacity and the amount of interference to the PUs. Also, we find that with a well designed SUF, the max-rate (MR) scheduler can approximate the proportional fair (PF) scheduler in the fairness performance.

    Chinese Abstract i English Abstract ii Acknowledgements iii Contents iv List of Tables vi List of Figures vii Glossary of Symbols ix 1 Introduction.............................................1 1.1 Introduction...........................................1 1.2 Thesis Outline.........................................3 2 Background and Literature Survey.........................4 2.1 Cognitive Radios.......................................4 2.2 Multiple Input Multiple Output Technique...............6 2.2.1 Spatial Multiplexing.................................7 2.2.2 Time Division Duplexing..............................9 2.2.3 Singular Value Decomposition in Spatial Multiplexing.9 2.3 Literature Survey.....................................10 3 System Model............................................12 4 Interference Mitigation Schedulers for the Uplink MIMO Cognitive Radios..........................................15 4.1 Scheduling Utility Function...........................15 4.1.1 SUF1................................................16 4.1.2 SUF2................................................16 4.1.3 SUF3................................................16 4.2 Interference Mitigation Schedulers....................17 4.2.1 Rate-Oriented Scheduler.............................17 4.2.2 Fairness-Oriented Scheduler.........................17 5 Simulation Results and Discussion.......................18 5.1 Performance Comparison between MIMO and SISO Cases....19 5.1.1 Throughput and Interference.........................19 5.1.2 Capacity Gain.......................................28 5.2 Performance Comparison between Schedulers in MIMO Case......................................................28 5.2.1 Throughput and Interference.........................28 5.2.2 Scheduled User Distribution.........................36 5.2.3 Fairness Index......................................47 6 Conclusion and Future Work..............................49 6.1 Conclusion............................................49 6.2 Future Work...........................................49 Bibliography..............................................50 Vita......................................................53

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