2014年5月29日台灣一家4G LTE (Long-Term Evolution) 電信業者宣布正式開台營運，這也讓台灣正式邁入高速行動上網的時代。LTE雖然有著高速率的技術優勢，但在初期網路涵蓋率仍有待加強的階段，上網速率的表現在都會區與郊區仍有一定的差距，即使在收訊良好的人口密集區，也由於同時上網的用戶數量增加而造成速率下降的情況發生。
本論文針對LTE下行的排程機制做一比較，並以實際的eNodeB 模擬多用戶分別在高、中、低SINR(Signal to Interference and Noise Ratio) 的不同收訊情況，在不同的排程機制下，包括傳統的資源公平Resource Fair (Round Robin) 及比例式公平Proportional Fair， 對於用戶平均下行速率、細胞吞吐率與容量及PRB (Physical Resource Block)與TTI (Transmission Time Interval) 的分配進行分析與評估。
由於無線環境是隨時處在變動之中，每個基地台的涵蓋及訊號分佈都不一，單一的排程機制並不能適用於所有的eNodeB。本論文結論中對各種不同涵蓋特性的基地台給予相對應的排程機制的建議，期能盡量符合現有網路的實際情況，在用戶公平性與基地台細胞容量之間取得一個最佳的協調。

On May 29, 2014, one of the Taiwan's 4G telecommunication operators announced the commercial launch, which also makes Taiwan formally enter the era of high-speed mobile internet. The 4G has a potential to provide a high transmission rate in Taiwan. However, in the early network rollout stage, the radio coverage is small, the data transmission throughput is not high enough and in dense urban areas the average user throughput may degrade due to too many users access the network simultaneously.
This thesis proposes a comparison of different LTE (Long-Term Evolution) downlink scheduling mechanisms including the traditional resource fair (Round Robin) and the proportional fair scheduling. With exiting eNodeB, we uses different scheduling mechanisms to obtain multi-users in high, medium and low SINR of reception situation, measure and analysis the average user throughput, cell throughput, cell capacity, PRB (Physical Resource Block) and TTI (Transmission Time Interval) utilization. According to the simulation results, we propose a scheduling mechanism to obtain the optimum tradeoff between the user fairness and cell capacity.

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