臺灣博碩士論文加值系統

在WCDMA系統中，傳統使用的頻道化碼為OVSF(Orthogonal Variable Spreading Factor)碼。以OVSF架構的理論，其會產生管理及搜尋上時間複雜度的問題，而在OVSF碼的配置方式上，則會產生著名的”Code Blocking問題”。本論文針對時間複雜度的問題，提出了”Smart OVSF Code Management Scheme”，將OVSF碼的配置及搜尋時間複雜度，分別bound在O(log(SF))和O(1)。至於Code Blocking的問題，則提出了一套以馬可夫決策程序為基礎的OVSF配碼機制。藉由馬可夫決策程序，我們也提出了一套允入控制機制，以期能提高系統業者的獲利期望值。經由模擬結果，可以看出本論文所提出的配碼機制在Code Blocking的表現來的比”Leftmost”和”Crowded-first”優秀。而本論文所提出的允入控制機制亦能有效降低系統業者的獲利損失。

This thesis examines code management, assignment, and call admission problems in a CDMA system which employs orthogonal variable spreading factor codes. The proposed code management scheme, referred to as Smart OVSF Code Management Scheme, improves the time complexity of code management and code searching, and achieves a bound of the time complexity of code management, and code searching at O(log(SF)), and O(1), respectively. We also propose a call assignment scheme based on Markov Decision Process (MDP). The proposed scheme yields better performance than that of “Leftmost” and “Crowded-first” in terms of code blocking. Based on MDP, we also propose a call admission control(CAC) mechanism to maximize system revenue. From the simulation results, we observed that our code assignment scheme can efficiently utilizes OVSF codes in the UMTS system and our CAC scheme reduces the system reward loss rate.

第一章 序論..………………………………………………………………..………1
第二章 背景知識與相關研究………………………………………………………..4
2.1 OVSF碼樹…..……………………………………………………………….5
2.2 OVSF Code Blocking..……………………………………………………….6
2.3 OVSF Code Assignment……………………………………………………..7
2.3.1 OVSF Code Assignment Schemes…..………………………………..8
第三章 智慧型OVSF碼樹管理機制…………..…………………………………..12
3.1 智慧型OVSF碼樹管理機制…………………………………….………..12
3.1.1 配置值(Assign Value)………………………………………………12
3.1.2 OVSF碼樹資料結構………………..………………………………13
3.1.3 節點編號公式………………………………………………………13
3.1.4 節點配置公式………………………………………………………14
3.1.5 可用碼配置…………………………………………………………17
第四章 以馬可夫決策程序為基礎的OVSF碼樹配置法..………………………..18
4.1 以MDP為基礎的OVSF碼樹配置法..…………………………………...18
4.2 馬可夫決策程序數學模組………………...………………………………21
4.3 以MDP為基礎的OVSF碼樹配置流程圖…...………………………..….24
第五章 以馬可夫決策程序為基礎的允入控制機制………………………………26
5.1 以MDP為基礎的允入控制機制公式…………………………………….27
5.2 以MDP為基礎的允入控制機制流程圖………………………………….28
第六章 系統模擬與分析……………………………………………………………30
6.1模擬環境介紹………………………………………………………………30
6.2 Performance Metric…………………………………………………………31
6.3 Performance Metric比較…………………………………………………...33
6.4 模擬結果分析……………………………………………………………...35
第七章 結論與未來工作……………………………………………………………51
參考文獻…………………………………………..…………………………………52

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