在長程演進技術(Long Term Evolation, LTE)小細胞(Small cell)高密度的佈建下，移動的使用者裝置(User Equipment, UE)會頻繁的換手，如果UE都只根據訊號強度來換手會導致使用即時串流的UE受到非即時串流UE的影響，為了要避免即時串流UE的服務品質(Quality of Service, QoS)受到影響，本論文在工研院(Industrial Technology Research Insititute, ITRI)的小細胞平台下實作一個考慮QoS的換手機制(QoS Handover Scheme, QHS)，我們根據UE傳送的資料型態與單位時間傳輸的資料量來決定每個UE的換手優先權，透過換手優先權使得QoS需求高的UE在換手時具有較高的優先權，接著我們會判斷UE的目標基地台是否可以負擔UE在單位時間傳輸的資料量，並在目標基地台無法滿足所有要換手UE的要求時，透過將低優先權的UE延遲換手，藉此保障高優先權UE的QoS。
為了要實作我們的QHS機制，我們新增量測UE的QoS模組，此模組會偵測UE傳輸的資料型態與量測UE在單位時間傳輸的資料量，另外我們也新增UE的換手優先權模組，其功能是為了要決定UE的換手優先權，最後，我們在小細胞上新增QoS換手模組，透過此模組來進行QoS的換手。為了要驗證我們所提出的QHS是否有改進UE的QoS，我們使用ITRI的小細胞平台來實作上述的模組，在完成實作後，我們比較原始ITRI的換手機制與QHS換手機制在UE的換手延遲時間、單位時間上傳與下傳資料量、封包遺失率與封包延遲的差別。

In the deployment of high-density LTE (Long Term Evolation) small cell, a mobile user equipment (UE) will handover frequently. If the handover of a UE is based on signal strength, a UE with real-time streaming will be affected by a UE with non real-time streaming. In order to maintain the quality of service (QoS) of a UE with real-time streaming, we implement a QoS Handover Scheme (QHS) on ITRI's (Industrial Technology Research Insititute) small cell platform. We decide each UE’s handover priority based on traffic type and data rate. In this way, a UE with high QoS requirement has a higher priority during handover. Additionally, the QHS can judge whether the target eNB can bear the data rates of all handover UEs. When the target eNB can’t bear all the QoS requirement of all the handover UE, the QoS of the high priority is guaranteed by delaying the handover of low priority UE. In order to implement our QHS, we add QoS detection module, which can detect the traffic type of all UE and measure their data rates. In addition, we add handover priority module, which can decide UE’s handover priority. Finally, we add QoS handover module on a small cell to do QoS handover. In order to validate whether our proposed QHS can improve UE’s QoS, we implement the aforementioned modules on ITRI’s small cell platform. After the implementation, we compare the original ITRI handover mechanism and the proposed QHS handover mechanism in terms of handover delay, data rate, packet loss ratio, and packet delay.

致謝 i
摘要 ii
Abstract iii
目錄 iv
圖表目錄 vi
第一章　導論 1
1.1 研究動機 1
1.2 研究方法 2
1.3 章節介紹 3
第二章　LTE小細胞的換手機制 4
2.1 LTE小細胞的標準 4
2.1.1 SON 5
2.1.2 LTE小細胞的換手 6
2.1.3 Measurement Report 7
2.2 ITRI小細胞 8
2.3 RTCP 11
2.3.1 Sender Report 12
2.3.2 Receiver Report 13
2.4 相關研究 13
2.5 本論文機制 15
第三章　考慮QoS的換手機制 17
3.1 QHS的系統架構 17
3.2 偵測UE傳送的資料型態 20
3.3 量測UE的AUDR與ADDR 21
3.4 修改ITRI的換手決策 22
3.5 UE的換手優先權演算法 26
第四章　ITRI平台的實作與結果分析 30
4.1 實驗環境與設備規格 30
4.2 在ITRI平台上的實作 33
4.2.1 量測UE的QoS模組 33
4.2.2 UE的換手優先權模組 38
4.2.3 回報UE的服務基地台模組 42
4.2.4 QoS換手與延遲換手模組 44
4.3 實作結果與分析 48
4.3.1 實作環境與設定 48
4.3.2 實驗結果 51
第五章　結論與未來工作 62
5.1 結論 62
5.2 未來工作 63
Reference 65
Acronyms 70
Index 72

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