在LTE-A異質網路的架構下，為了有效解決細胞間彼此干擾的問題，第三代合作夥伴計劃(3rd Generation Partnership Project，簡稱3GPP)提出了「增強型細胞間干擾消除技術」(Enhanced inter-cell interference coordination，簡稱eICIC)，並利用傳送近乎空白子訊框(Almost blank subframe，簡稱ABS)，來解決macrocell基地台對於small cell訊號干擾的問題；另一方面，為了延長使用者設備(User equipment，簡稱UE)的電池續航力，3GPP也同時制定「非連續接收」(Discontinuous Reception，簡稱DRX)機制，該機制透過讓UE週期性地關閉射頻電路以便節省其能源消耗；然而，當macrocell基地台使用ABS時，由於不會傳送使用者資料給旗下的UE，而UE在睡眠模式時亦無法接收資料，也因此，倘若我們能在UE進入睡眠模式時順勢使用ABS，就能同時達到降低對small cell的干擾和UE省電的效果；基於上述的觀察，本論文將根據UE的通道狀況、資料產生速率，以及服務品質的需求，來動態調整DRX參數和ABS的使用時機，以減少UE的耗電量、降低GBR flow的封包遺失率，以及提升網路整體的吞吐量。

In order to solve the cell-interference problem in LTE-A heterogeneous networks, 3GPP proposes the technique of enhanced inter-cell interference coordination (eICIC). It uses almost blank subframes (ABSs) to alleviate signal interference by a macrocell eNB to small cells. In addition, 3GPP also proposes a discontinuous reception (DRX) mechanism to help extend battery lifetime of user equipments (UEs). It allows UE to turn off radio frequency circuit periodically to save energy consumption. However, during an ABS, the macrocell eNB doesn’t send user data to UEs. Besides, UEs cannot receive data in the sleeping mode. Therefore, if we allow UEs to enter the sleeping mode during ABSs, not only the interference problem is alleviated but also UEs can save more energy. Based on the above observation, the objectives of this thesis are to reduce energy consumption, decrease packet loss rate of guaranteed bit rate (GBR) flows, and improve overall throughput by considering channel condition, data rate, and quality of service (QoS) requirements of UEs adaptively to adjust the DRX parameters and the ABS mechanism.

論文審定書 i
致謝 ii
摘要 iii
Abstract iv
目錄 v
圖次 vii
表次 viii
一、 導論 1
1.1 前言 1
1.2 研究動機 3
1.3 論文貢獻與章節架構 4
二、 LTE-A技術介紹 5
2.1 LTE-A頻譜資源與服務品質分級 5
2.2 增強型細胞間干擾消除技術 10
2.3 非連續接收機制 11
三、 問題定義與相關研究 13
3.1 網路架構與問題定義 13
3.2 相關文獻探討 14
四、 研究方法 17
4.1 步驟一：求出CQI、 Long DRX cycle與ABS cycle 20
4.2 步驟二：計算UE的flow需要多少個PRB 21
4.3 步驟三：計算UE預計分配到的PRB與ABS使用數量 23
4.4 步驟四：決定On duration timer與DRX offset 26
4.5 演算法設計原由 28
五、 模擬結果與分析 30
5.1 能源消耗比較 34
5.2 吞吐量比較 36
5.2.1 系統整體吞吐量 36
5.2.2 Macrocell吞吐量 38
5.2.3 Picocell吞吐量 40
5.3 能源效率比較 42
5.4 GBR flow封包遺失率比較 44
5.4.1 系統封包遺失率 44
5.4.2 Macrocell封包遺失率 46
5.4.3 Picocell封包遺失率 48
5.5 不同場景之比較 50
5.5.1 系統能源消耗 50
5.5.2 系統吞吐量 51
5.5.3 系統能源效率 53
5.5.4 系統GBR flow封包遺失率 54
六、 結論與未來展望 56
參考文獻 57

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