UMTS核心網路掠奪性排隊機制之研究

Abstract

本論文於第三代全球行動通訊系統(UMTS)之核心網路(Core Network)中，提出以角色為基礎之佇列(RBQ, Role Based Queueing)掠奪式(preemptive)排程方法，依據行動使用者之角色而提供不同等級之服務品質(QoS)，並且特別針對於UMTS定義之服務品質等級中之背景資料型態(background traffic)為實驗資料型式；論文中設計一適用於角色基礎之佇列，一具掠奪性之移入排程方法，及一具優先權式之循環移出排程方法；利用網路實驗工具NS2驗證模擬後，發現RBQ排程系統機制能於不同頻寬假設中，當總閘道器頻寬無法負荷進入之總流量頻寬時，能夠提供以給定角色為基礎之掠奪性排程；當負荷總流量頻寬低於閘道器頻寬時，能夠提供以各流量頻寬為基礎之公平性移入效能。

This paper describes a RBQ (Role Based Queueing) preemptive scheduling discipline based on the Core Network in UMTS. RBQ provides diverse quality of service towards to Background data traffic that is defined by UMTS QoS class. In the RBQ system, we design a role based queue, a preemptive enqueue mechanism and a preemptive Round-Robin dequeue mechanism. With NS2 simulation, we figure out that when total flow bandwidth is in excess of gateway bandwidth, RBQ can provide a preemptive scheduling based on the given roles. On the other hand, when total bandwidth is not in excess of gateway bandwidth, RBQ can provide a fair enqueue throughput based on each flow bandwidth.