| 摘要: | 在行動通訊系統中上下行資源皆是由基地台作安排，而周圍鄰近的基地台皆會因為基地台間干擾(Inter-cell Interference, ICI)的問題使得系統整體吞吐量(Throughput)下降，特別是基地台邊緣(Cell-edge)的UE (User Equipment)，並且因為5G相比4G使用了頻率更高的頻段，訊號衰減的更快，因此需要更高密度的架設基地台來達成與4G相同的訊號涵蓋，也因此ICI所發生的區域會更加的密集，而為了緩解ICI的影響，鄰近的基地台會彼此溝通協調，並根據協調的結果來進行資源的安排，如此一來就可以抑制ICI的影響，並且提升Cell-edge UE的Throughput，進一步的提升整體UE的公平性。資源安排的方法是影響系統整體Throughput和公平性的主要因素，而基地台間干擾協調(Inter-cell Interference Coordination, ICIC)的方法則是次要的因素，但隨著Cell-edge UE數量越來越多，UE呈不均勻分布，ICIC對於Throughput和公平性的影響會越來越大，因此本論文將會朝著這個方向去做分析。
本論文將Maximum Rate (MR)、Proportional Fair (PF)、Opportunistic Proportional Fair (OPF)以及Round Robin (RR)這4種Scheduling schemes結合了Reuse 1、Soft Frequency Reuse (SFR)、Muting和Joint Transmission Coordinated Multi-Point (JT CoMP)這4種ICIC schemes，並於7個基地台的環境中使用5G C-RAN架構來模擬這16種方法。在模擬結果中分析並比較了Throughput與公平性，並且將16種方法依據Scheduling scheme分成4組來討論，在不同的UE分布下討論了4種ICIC schemes的影響。整體來說PF scheduler在系統整體Throughput與公平性之間找到了一個平衡點，而OPF scheduler提供了一種Throughput與公平性介於MR與PF之間的新選擇，並且在大多數情況下JT CoMP提供了Cell-edge UE最高的Throughput，並且公平性也是最高的。
;In mobile communication systems, both uplink and downlink resources are allocated by the base stations. However, neighboring base stations can cause a decrease in the overall system throughput due to inter-cell interference (ICI), especially for User Equipment (UE) at the cell edge. Additionally, since 5G utilizes higher-frequency bands compared to 4G, the signal attenuates faster, requiring a denser deployment of base stations to achieve the same signal coverage as 4G. Therefore, the area where ICI occurs will be denser. To mitigate the impact of ICI, neighboring base stations communicate and coordinate with each other, determining resource allocation based on the coordination results. This approach helps suppress the effects of ICI, improving the throughput of Cell-edge UEs and further enhancing the overall fairness of UEs. The method of resource allocation is a primary factor that affects the overall throughput and fairness of the system, while Inter-cell Interference Coordination (ICIC) between base stations is a secondary factor. However, with an increasing number of Cell-edge UEs and non-uniform distribution of UEs, the impact of ICIC on throughput and fairness becomes more significant. Therefore, this thesis will analyze in this direction.
This thesis combines four scheduling schemes, namely Maximum Rate (MR), Proportional Fair (PF), Opportunistic Proportional Fair (OPF), and Round Robin (RR), with four ICIC schemes: Reuse 1, Soft Frequency Reuse (SFR), Muting, and Joint Transmission Coordinated Multi-Point (JT CoMP). These sixteen methods are simulated using a 5G C-RAN architecture in a scenario with seven base stations. The simulation results analyze and compare the throughput and fairness. The sixteen methods are divided into four groups based on the scheduling scheme for further discussion, considering the influence of the four ICIC schemes under different UE distributions. In general, the PF scheduler finds a balance between the overall system throughput and fairness. The OPF scheduler offers a new option that lies between MR and PF in terms of throughput and fairness. In most cases, JT CoMP offers the highest throughput for Cell-edge UEs and also achieves the highest level of fairness. |
