臺灣博碩士論文加值系統

對於經營第二代無線通訊的業者早已經面臨了有限的射頻頻寬不足的挑戰。未來因有愈來愈多的顧客會需要更多的射頻頻寬來提供更多樣化的多媒體應用，因此在第三代或未來的無線通訊，有限的射頻頻寬在應用上則更相形見拙。而如何有效運用有限的射頻頻寬與保證提供一穩定及連續性的高品質服務，這將是第三代行動通信業者與系統業者為公司及顧客獲得最大利益上的主要工作。對於已經在通信線上的顧客，保持最高的通訊品質與低話務中斷率是無庸致疑的。因此，要有高的射頻頻寬利用率與維持客戶所需的通訊品質會是兩難的事。
雖然現有許多話務管制演算法被提出，但我們仍研究提出幾種可用於多媒體無線通訊網路的演算法來滿足客戶的需求。在話務管制演算法的發展考量上，如何提高射頻頻寬使用率與降低換手中斷率為主要之考量。新發展的話務演算法將以三種重要的性能指標來作性能評估，這三種指標分別為話務中斷率、換手中斷率與射頻頻寬使用率。共有兩種傳統的話務演算法和數個新發展的話務演算法在應用於未來多媒體的無線網路將被仔細的比較與評估。所以每個新發展的話務演算法會有詳細的性能分析與比較。
這裡所謂的傳統話務演算法可分為對要換手的話務或高優先的話務有或無預留射頻頻寬。而所提出數個新的話務演算法乃是一種動態的射頻頻寬預留機制，這機制則由幾乎即時的網路話務情況所計算的實際值來動態調整。我們也採用事前得到客戶的允許來降低所要提供服務所需的射頻頻寬，以增加其射頻頻寬的使用率。
本論文所提出的各種話務演算法經過數值模擬可知：所發展的話務演算法相對於兩個傳統演算法，Adaptive I可同時提供較高的射頻頻寬使用率和較低的總話務中斷率。而話務演算法Adaptive 4 (Adaptive 4_0329) 相對於傳統的話務演算法則有2%以上的射頻頻寬使用率的改善，但在換手中斷率則表現不佳。而話務演算法Adaptive 5 (Adaptive 4_0330)則有2%以上的換手中斷率的改善。因新發展的話務演算法有許多的參數可針對不同的話務情況作不同的設定來適合不同網路情形，這也是我們所發展新話務演算法的優點，以利於適應不同的話務環境。

We already faced a challenge about the radio resource limitation for current 2G cellular wireless operators. It will be worse for multimedia application in 3G or future generation wireless network system due to more and more people need more radio resources to have more fancy multimedia applications. How to efficiently utilize limited radio resources and guarantee the best constant quality to gain the best benefit for companies and customers will be major tasks for 3G wireless network equipment vendors and system operators. It is no doubt to keep the best quality and low call-dropping rate for on-line customers. Therefore, it will be a dilemma between radio channel utilization and required QoS. Although a lot of Call Admission Control (CAC) algorithms were already introduced in present papers, we are still studying to provide some possible new algorithms used in multimedia radio network to meet customers’ demands. How to improve radio channel utilization and lower handoff call dropping rate are key issues for our CAC algorithm development consideration. The key performance indicators of new developed CAC algorithms are evaluated by new call dropping rate, handoff dropping rate, and radio channel utilization. The comparison between two traditional CAC algorithms and several new developed algorithms will be investigated the performance what those new algorithms can be used in future multimedia wireless network. Individually detailed analysis and comparison of each new algorithm will be also addressed in this paper.
Those traditional algorithms are without guard channel reservation and with guard channel reservation for handoff calls or high priority calls. Proposed several new algorithms are based on adaptive guard channel concept by almost real-time measured data of network to automatically adjust reserved guard channels. We also introduce the concept to degrade required traffic bandwidth of new call to the acceptable level by customers with permission to increase channel utilization.
Simulation results show that our algorithm, Adaptive I, can provide higher channel utilization and lower total call dropping rate simultaneously than traditional ones. The algorithm Adaptive 4 (Adaptive 4_0329) can perform above 2% improvement in channel utilization compared with traditional ones, but is fail to lower handoff call dropping rate. The algorithm Adaptvie 5 (Adaptive 4_0330) perform above 2% improvement in handoff call dropping rate. Due to new developed algorithms have lots of parameters to set for different traffic conditions, this is major benefit what we proposed new algorithms are more flexible to fit variable traffic environments.

1 Introduction 1
1.1 Background Overview 3
1.2 Motivation and Purposes 3
1.3 Research Directions and Methodology 5
1.3.1 Research Directions 5
1.3.2 Methodology 5
1.4 Organization of This Thesis 6
2 Overview of QoS Control of Future Wireless Network 8
2.1 QoS Introduction of Next Generation Network 8
2.1.1 QoS of 3Gpp Defined 8
2.1.2 Key Performance Indictors of QoS 9
2.1.3 QoS Control Mechanism 11
2.2 Functional Description of CAC 12
2.2.1 Introduction 12
2.2.2 Functional Block Descriptions 13
2.3 Papers Review for CAC Algorithm Techniques 14
3 Traditional CAC Algorithms and Models 18
3.1 Introduction 18
3.2 Without Guard Channel Reservation 19
3.2.1 Without Queuing Buffer System for Without Guard Channel Reservation ……………………………………………………………………………20
3.2.2 Algorithm for Simulation 21
3.2.3 With Queuing Buffer System for Without Guard Channel Reservation 23
3.3 With Guard Channel Reservation 25
3.3.1 Without Queuing Buffer System for Fix Guard Channel Reservation 26
3.3.2 Algorithm for Simulation 28
3.3.3 With Queuing Buffer System for Fix Guard Channel Reservation 30
3.4 Summary….. 32
4 New Adaptive CAC Algorithms Development 34
4.1 Introduction 34
4.2 CAC Algorithm Adaptive I 42
4.2.1 Algorithm Structure 43
4.2.2 Performance Study 45
4.2.2.1 Call Dropping Trend and Channel Utilization Trend in Time Axis 45
4.2.2.2 QoS Parameter Variation Study 52
4.2.2.3 Call Dropping and Channel Utilization vs. QoS Parameter Variation 55
4.2.2.4 Summary 57
4.3 CAC Algorithm Adaptive II 59
4.3.1 Algorithm Structure 59
4.3.2 Performance Study 62
4.3.2.1 Call Dropping Trend and Channel Utilization Trend in Time Axis 62
4.3.2.2 QoS Parameter Variation Study 69
4.3.2.3 Call Dropping and Channel Utilization vs. QoS Parameter Variation 72
4.3.2.4 Summary 74
4.4 CAC Algorithm: QoS Control Method 76
4.4.1 Algorithm Structure 76
4.4.2 Performance Study 77
4.4.2.1 Call Dropping Trend and Channel Utilization Trend in Time Axis 77
4.4.2.2 QoS Parameter Variation Study 84
4.4.2.3 Call Dropping and Channel Utilization vs. QoS Parameter Variation 87
4.4.2.4 Summary 89
4.5 CAC Algorithm: QoS Control, Adaptive III 91
4.5.1 Algorithm Structure 91
4.5.2 Performance Study 92
4.5.2.1 Call Dropping Trend and Channel Utilization Trend in Time Axis 92
4.5.2.2 QoS Parameter Variation Study 99
4.5.2.3 Call Dropping and Channel Utilization vs. QoS Parameter Variation ………………………………………………………………………102
4.5.2.4 Summary 104
4.6 CAC Algorithm: Handoff Rate Control, Adaptive 5 106
4.6.1 Algorithm Structure 107
4.6.2 Performance Study 108
4.6.2.1 QoS Parameter Variation Study 108
4.6.2.2 Call Dropping and Channel Utilization vs. QoS Parameter Variation 112
4.6.3 Summary… 113
4.7 CAC Algorithm: Handoff Rate Control, Adaptive 4 114
4.7.1 Algorithm Structure 115
4.7.2 Performance Study 116
4.7.2.1 QoS Parameter Variation Study 116
4.7.2.2 Call Dropping and Channel Utilization vs. QoS Parameter Variation 120
4.7.3 Summary 121
5 Simulation Results Analysis 122
5.1 Overall Performance Comparison under Different Traffic Arrival 122
5.2 Summary… 133
5.2.1 New Call Dropping Rate Comparison 133
5.2.2 Handoff Call Dropping Rate Comparison 133
5.2.3 Total Call Dropping Rate Comparison 134
5.2.4 Channel Utilization Comparison 134
6 Conclusions and Future works 136
REFERENCES 138

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