在無線感知網路(CRNs)中，主要用戶(PUs)擁有使用頻譜的絕對優先權。而為了有效率地利用頻譜，次級用戶(SUs)可透過跳頻(Channel hopping)技術，動態地使用主要用戶未使用的頻道進行通訊。
現存的跳頻技術大都著重於頻道對稱模型(Symmetric model)。在此模型下，所有次級用戶的可用頻道皆相同。然而，在實體的無線感知網路環境中，所有次級用戶可用頻道不盡相同的非對稱模型(Asymmetric model)是較為實際的。在本篇論文中，我們提出一套通用的跳頻演算法，在非對稱模型中，不僅能夠以短於其他方法的週期保證頻道的會合，也不需要對次級用戶的可用頻道進行任何限制。而根據我們進行的模擬結果，此演算法擁有優於其他方法的最大條件會合時間(MCTTR)，意即在次級用戶之可用頻道不盡相同的情況下，能夠以最短的時間保證會合的出現。

In cognitive radio networks (CRNs), primary users (PUs) have the absolute priority to access the license channels. To efficiently utilize the spectrum, secondary users (SUs) can dynamically access the unused channels by channel hopping (CH) schemes.
Most existing CH schemes focus on the symmetric model that assumes all SUs have the same available channel set. However, the asymmetric model, where SUs may have different available channels sets, is more critical in the real CRN environment. In this thesis, we propose a universal channel hopping algorithm called Triple-Double Matrix (TDM) that can guarantee rendezvous within shorter period than the previous works under the asymmetric model without any constraints on the available channels of each SU. According to our simulation results, TDM has better maximum conditional time-to-rendezvous (MCTTR) than previous works.

Chapter 1: Introduction 1
Chapter 2: Related Works 5
Chapter 3: Triple-Double Matrix (TDM) Algorithm 8
3.1 Problem Definition 8
3.2 Triple-Double Matrix (TDM) Scheme 9
3.3 Verification of Guaranteed Rendezvous for TDM 15
Chapter 4: Performance Evaluation 33
4.1 Performance Analysis 33
4.2 Simulation Setup 34
4.3 Impact of the Number of Total Available Channels 34
4.4 Impact of PU Occupations 36
4.5 Impact of Rare Common Channels 37
4.6 Impact of Start Channel with PU Occupations 38
4.7 Symmetric Model 40
Chapter 5: Conclusion 42
References 43

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