伴隨無線通訊技術的迅速發展，蜂巢式網路架構發展更加多樣化且複雜，因此近年來有許多針對LTE-A中如何進行快速且準確換手的研究。而在3GPP Release 8中提出ㄧ記錄在基地台上之使用者歷史資訊(UE History Information)的設置，其主要目的在於當使用者進行換手時提供可用來判斷換手目標基地台的歷史記錄，此資訊主要記錄了最後拜訪細胞的細胞編號(Cell ID)、細胞類型(Cell Type)和UE停留在細胞中的時間(Time UE Stayed in Cell)，由此可知歷史資訊對於換手時可用來參考的實用性。本文提出一進階的使用者歷史資訊記錄與換手預測機制，藉由使用者空間區域與時間區域性和觸發時間(Time To Trigger)的歷史資訊記錄，降低換手失敗率與乒乓換手率的發生。

In response to the rapidly developing of wireless communication technology, the deployed of eNB is denser and more complex. The research of how to handover accurately and fast in LTE-A are discussed much in recent years. In 3GPP Release 8, the UE History Information recorded by eNB was first proposed, it's proposed to provide eNB to judge the target eNB in handover processes. The history information includes the Cell ID and Time UE stayed in cell. We proposed an advance UE history information to reduce the handover failure rate and ping-pong handover rate by using the advance history information with Region-Domain, Time-Domain and Time To Trigger.

目錄
第一章	緒論	1
1-1	研究背景	2
1-2	研究動機與目的	3
1-3	論文架構	4
第二章	相關技術與研究	5
2-1	換手基本流程	5
2-2	觸發時間(Time To Trigger,TTT) 介紹	9
2-3	LTE-A中的換手失敗與乒乓換手介紹	11
	Too Early Handover	11
	Too Late Handover	12
	Handover to Wrong Cell	13
	Ping Pong Handover	14
2-4	使用者設備歷史資訊	15
	使用者設備歷史資訊(UE History Information)	15
	最後拜訪細胞資訊(Last Visited Cell Information)	16
2-5	目標基地台的預測	17
第三章	應用LTE-A使用者歷史資訊之換手預測機制	19
3-1	系統設定	19
3-2	預測機制概述	21
	連接次數	21
	重連時間點	23
	日連接時間點	24
	日連接時間長度	25
	觸發時間記錄	26
3-3	提出機制之流程	27
第四章	模擬與分析	34
4-1	模擬環境	35
4-2	模擬結果分析與比較	37
第五章	結論與未來研究方向	40
5-1	結論	40
5-2	未來研究方向	41
參考文獻	42
附錄–英文論文	45

圖目錄
圖 1、換手流程圖	8
圖 2、TTT示意圖	9
圖 3、過早換手範例圖	11
圖 4、過晚換手範例圖	12
圖 5、換手至錯誤細胞範例圖	13
圖 6、乒乓換手範例圖	14
圖 7、使用者設備歷史資訊規格	15
圖 8、上一次拜訪基地台記錄規格	16
圖 9、提出之使用者設備歷史記錄資訊	20
圖 10、連接次數示意圖	22
圖 11、日連接時間點示意圖	24
圖 12、日連接時間長度示意圖	25
圖 13、資訊刪除流程圖	28
圖 14、資訊更新流程圖	30
圖 15、機制運作流程圖	32
圖 16、提出機制於換手流程中運作時機	33
圖 17、換手失敗率比較圖	38
圖 18、乒乓換手率比較圖	39

表目錄
表 1、觸發時間的16項定義值	10
表 2、實驗參數	36

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