近年來行動數據流量正在爆炸性增長，為了滿足多樣式的無線連接需求，因此正在積極研發中的第五代移動通訊系統(5G)，主要是希望突破過去蜂巢式基地台的限制，在火車站、機場甚至室內辦公大樓當中，發展高密集的小型基地台(Dense Small Cell Network)環境[27]，可以容納更多的裝置且具備低延遲性，然而基地台的功率消耗占總體能源消耗的百分之八十，為了呼應節能減碳議題，3GPP提出基地台睡眠(Small Cell On/Off)的技術，允許環境中的小型機地台可以在負載量小於一定的門檻值時進入睡眠模式，藉此方法既可以達到省電之目的。
然而，在過往的文獻中我們發現到能夠節省的能源有限，因此本論文將在密集小型基地台的環境中探討基地台睡眠機制。首先，定義所要解決的問題以最小化環境的能源消耗為目標且滿足所有使用者傳輸需求，之後將此問題對應到Bin-Packing Problem，因此我們所要解決的問題為一NP-Hard Problem，為了解決這個問題，我們提出一個基於基地台分群的睡眠機制，一開始將環境中所有基地台做適當的分群之後，在各個群集之中獲得更佳的節能情形，同時加入資源利用度考量，希望在新的使用者加入網路之後，盡可能地避免開啟正在睡眠當中的基地台，此外各個群集皆為平行地運作，可降低時間複雜度，最後將各個群集之間做更進ㄧ步的睡眠機制。
此外，我們也針對本篇論文所提出的演算法進行時間複雜度分析，最後，透過模擬分析顯示，本篇論文所提出的方法能夠因應不同的情境，無論使用者的分佈情行為何，皆能夠成功地降低整體網路中的能源消耗，同時滿足所有使用者的最低傳輸需求，最終達到盡可能地最小化能源消耗之目的。

In recent years, the use of mobile wireless devices has been growing exponentially. In order to serve intense traffic such as at train stations, at airport gates, or in classroom buildings, the investigation of 5G for the next generation of mobile telecommunication has been triggered[27]. Additionally, one promising solution is the deployment of massive small cells, called dense small cell network, which can get more capacity. However, the base stations are one of the biggest contributors for power consumption. To address the power consumption challenge, the Small Cell On/Off mechanism are discussed by the 3GPP.
Previous solutions for Small Cell On/Off mechanism in dense small cell network could get energy saving. In this paper, we aim to minimize the total power consumption of network while guarantee the quality of service(QoS) of all the users. First, we find that the base stations(BSs) activation problem for minimizing network power consumption is an NP-Hard problem. To address the problem and further reduce the energy consumption of massive small cells, we proposed a clustering-based scheme for Small Cell On/Off method in dense small cell network. First, the base stations are clustered based on distance, and then we discuss inter-cluster and intra-cluster separately for Small Cell On/Off mechanism. Finally, we can improve energy consumption and reduce the time complexity.
Additionally, we also analysis the time complexity for proposed algorithm. Simulation results demonstrate that proposed method can further reduce the energy consumption as well as guarantee the quality of service(QoS) of all the users in dense small cell network.

[第一章 導論 + 01]
[1.1 前言 + 01]
[1.2 研究動機 + 03]
[1.3 論文架構 + 06]
[第二章 相關背景與研究 + 07]
[2.1 長期演進技術(LTE)簡介 + 07]
[2.2 LTE相關技術介紹 + 10]
[2.2.1 頻譜利用(Spectrum Utilization) + 10]
[2.2.2 正交分頻多重存取技術(OFDMA) + 10]
[2.2.3 單載波分頻多工存取技術(SC-FDMA) + 11]
[2.2.4 資源區塊(Physical Resource Block，PRB) + 12]
[2.2.5 通道狀況資訊(Channel Status Information，CSI) + 13]
[2.3 異質性網路(HetNet) + 16]
[2.4 基地台睡眠省電技術(Small Cell on/off) + 19]
[2.5 相關論文 + 22]
[第三章 研究方法 + 24]
[3.1 系統架構 + 24]
[3.1.1 問題描述 + 25]
[3.1.2 方法架構 + 29]
[3.2 基地台負載分類 + 31]
[3.3 基地台分群機制 + 33]
[3.4 基地台睡眠機制 + 36]
[3.4.1 群集中睡眠機制 + 36]
[3.4.2 群集間睡眠機制 + 44]
[3.5 時間複雜度分析 + 46]
[第四章 模擬與效能分析 + 49]
[4.1 模擬環境與參數設定 + 49]
[4.2 模擬結果與效能分析 + 50]
[第五章 結論 + 69]
[參考文獻 + 70]

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