Construction and Analysis of Multi-MTTR Channel-Hopping Sequences for Cognitive Radio Networks

在本論文中設計了應用所建造之方式，於感知無線電環境中新的“非同步非對稱”通道跳頻碼。所設計之通道跳頻碼滿足碼之通道交會維度、成對序列碼位移不變特性並且有較多之碼個數。於感知無線電環境中首次依最大交會時間分群建構通道跳頻碼，並且在碼之個數與最大交會時間之間取得平衡。此外分析了新設計之通道跳頻碼在封包碰撞迴避機制下的封包交換利用率以及封包交換利用率之變異數。研究結果顯示，新設計之通道跳頻碼擁有比現今其他非同步非對稱通道跳頻碼較多的碼之個數以及較小的封包交換利用率之變異數，因此能在感知無線電環境下達到更快速、更穩定及更均勻的封包流通量。此外本論文提出了結合交會時間與封包交換利用率的兩個新分析模型。In this thesis, a family of channel-hopping (CH) sequences, so-called multi-MTTR asynchronous-asymmetric prime sequences (MAAPSs), for cognitive radio networks (CRNs) is designed and analyzed. They have known and enlarged cardinality (for the benefit of user identification), full degree of rendezvous, and pairwise shift invariant. For the first time, the MAAPSs can be partitioned into multiple subsets of CH sequences with adjustable maximum time-to-rendezvous (MTTR), supporting a trade-off between cardinality and MTTR in scalable CRNs. With a channel-contention-resolution mechanism in use, the rendezvous-success (RS) rate and variance of the MAAPSs in a practical CRN are analyzed. With short MTTR and smaller RS rate variance, the MAAPSs can support quicker, more stable and uniform rendezvous processes than their counterparts. Finally, the analytical models of two combined metrics of TTR and RS rate, so-called maximum and average time-to-rendezvous-success, are formulated and validated with computer simulation.Abstract ii Contents iii List of Figures v List of Tables vi Chapter 1 Introduction 1 1.1 Background 1 1.2 Motivation 2 1.3 Contributions of This Thesis 2 1.4 Outline of Thesis 3 Chapter 2 Preliminary Materials 4 2.1 Design Criteria 4 2.2 Performance Metrics 4 Chapter 3 Design of Multi-MTTR Asynchronous-Asymmetric CH Sequences 6 3.1 Unique Multi-MTTR property 9 3.2 Scalable-MTTR Cognitive Radio Networks 11 3.3 Comparisons With Other CH Sequences 13 Chapter 4 Performance Analyses of the MAAPSs 16 4.1 Rendezvous-Success Rate 16 4.2 RS-Rate Variance 20 4.3 Analysis of MTTR 23 Chapter 5 New Analytical Models of MTTRS and ATTRS 28 Chapter 6 Conclusion 34 Appendix 35 References 3