臺灣博碩士論文加值系統

近些年來由於個人行動通訊之需求及發展，各種廣域或區域之無線及有線軍/民用通訊系統，隨者相關電子及通訊產業技術之創新及突破而蓬勃發展。然而，眾多通訊系統間之相互干擾現象及問題，縱有一定之標準規範仍普遍存在，尤有甚者為蓄意性之干擾，其意圖影響整個通訊系統之私密資訊接收性能。因此，如何降低通訊系統被干擾影響便相形重要；同時研究如何評估通訊系統之抗干擾(Anti-jamming)性能更是重要研究課題。本論文將把重點置於抗干擾性能之系統層次評估模擬分析上，並以衛星通訊系統為例評估探討其系統抗干擾性能。

Due to the requirements and developments of personal mobile communications for the past several decades, all kinds of global and local wireless/wire and military/civil communications systems are developing flourishingly in accordance with the novelties and breakthrough of all related electronic and communication techniques. Nevertheless, there still exist mutual interference phenomena and problems among many communication systems even with many standards specified, especially when the jamming sources are intentional, which try to effect the private information convey of the whole communications system. Therefore, it’s of particular importance to mitigate or decrease the effects of jamming. Furthermore, it’s a very important research topic to evaluate the performance of anti-jamming (AJ).
In this thesis, we will focus on the simulation and analysis of anti-jamming topic. Moreover, a satellite communications system is illustrated to study and evaluate its AJ performances.

CHAPTER 1 INTRODUCTION 1
1-1. MOTIVATIONS AND OBJECTIVES 1
1-2. SATELLITE COMMUNICATIONS FUNDAMENTALS 1
1-3. S2 AGAINST COMMUNICATIONS JAMMING 5
1-4. THESIS ORGANIZATION 7
CHAPTER 2 S2 MODULATION TECHNIQUES REVIEWS 8
2-1. S2 COMMUNICATIONS FUNDAMENTALS 8
2-2. FREQUENCY HOPPING 9
2-2-1. Transmitter Functions 10
2-2-2. Signal properties 10
2-2-3. Receiver Functions 13
2-3. TIME HOPPING 14
2-3-1. Transmitter Functions 15
2-3-2. Signal Properties 16
2-3-3. Receiver Functions 16
2-4. DIRECT SEQUENCE 17
2-4-1. Transmitter Functions 19
2-4-2. Signal Properties 21
2-4-3. Receiver Functions 23
2-5. CHARACTERISTICS OF SPREAD SPECTRUM AJ SYSTEMS 25
2-5-1. Spread Spectrum AJ Systems 25
2-5-2. Time Hopping, AJ Systems 25
2-5-3. Frequency Hopping, AJ Systems 27
2-5-4. Direct Sequence, AJ Systems 27
2-5-5. Hybrid AJ Systems 28
CHAPTER 3 S2 DESIGN TO ACHIEVE ANTI-JAM PROTECTIONS 29
3-1. COMMUNICATIONS JAMMING OVERVIEW 30
3-1-1. Correlated Jamming Strategies 31
3-1-2. Noncorrelated Jamming Strategies 32
3-2. MEASURES OF ANTI-JAM PROTECTION 42
3-3. PROCESSING GAIN IN S2 SYSTEMS 43
3-4. THE EFFECTIVENESS AND EFFICIENCY OF JAMMERS 44
CHAPTER 4 PERFORMANCE ANALYSIS UNDER JAMMING ENVIRONMENTS 46
4-1. LINK BUDGET 46
4-2. TWO EXAMPLES AND VARIOUS RESULTS 47
4-4-1. The Uplink Case 48
4-4-2. The Downlink Case 52
4-3. JAMMING CONTOURS IN SPACE 55
4-3-1. Contours of Constant J/S 56
4-3-2. Jamming Contours Caused by Time Limitations 62
4-3-3. Jamming Contours under Noncorrealated Jammers 68
CHAPTER 5 CONCLUSIONS 72
REFERENCES 74

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