【摘要】：LTE(Long Term Evolution,長期演進)下行資源調(diào)度是保證LTE移動通信系統(tǒng)質(zhì)量的關鍵技術。目前移動終端實時業(yè)務對QoS(Quality of Service,服務質(zhì)量)的要求日益提高,在有限的頻譜資源下,如何保證實時業(yè)務的QoS,提高用戶體驗質(zhì)量,同時保障非實時業(yè)務的吞吐量,以及二者之間的公平性,是值得研究的重要問題。本文在研究分析了一些經(jīng)典調(diào)度方法基礎上,根據(jù)指數(shù)方法提出一種基于丟包率自適應時延閾值的實時業(yè)務調(diào)度方法PLR-D。對于實時業(yè)務,時延與丟包率是緊密相關的,根據(jù)實時丟包率自適應修改時延閾值。使得在保證實時業(yè)務吞吐量基礎上,提升時延與丟包率指標,并提高同種業(yè)務之間的公平性。在實時調(diào)度方法基礎上,改進了一種基于QoS的兩層調(diào)度方案。改進的調(diào)度算法上層以一個LTE幀(10個TTI,傳輸間隔)為單位進行一個無線幀內(nèi)的傳輸數(shù)據(jù)量計算;下層調(diào)度以一個TTI為周期,對不同業(yè)務采取不同方法進行調(diào)度,對實時業(yè)務運用PLR-D方法、對非實時業(yè)務使用PF(Proportional fair,比例公平調(diào)度)方法,并在兩者之間引入平衡函數(shù),利用閉環(huán)結構調(diào)節(jié)不同業(yè)務之間的公平性。建立了LTE移動通信系統(tǒng)的系統(tǒng)級仿真平臺,并進行了仿真實驗。通過PLR-D方法與其他方法對比實驗,驗證新的方法在提高實時業(yè)務QoS上和業(yè)務之間公平性上的有效性。通過將改進的兩層調(diào)度方案與經(jīng)典的多業(yè)務調(diào)度方案對比實驗,驗證新的方法在降低實時業(yè)務丟包率、時延的情況下,同時提高了非實時業(yè)務的吞吐量。驗證了該方案對實時和非實時業(yè)務之間公平性的保障。
[Abstract]:LTE (Long Term Evolution, (long-term Evolution) downlink resource scheduling is the key technology to ensure the quality of LTE mobile communication system. At present, the requirement of QoS (Quality of Service, (quality of Service) for real-time service of mobile terminal is increasing day by day. Under the limited spectrum resources, how to guarantee the QoS, of real-time service to improve the quality of user experience and the throughput of non-real-time service, And the fairness between them is an important issue worth studying. In this paper, based on the analysis of some classical scheduling methods, a real-time traffic scheduling method PLR-D. based on packet loss rate adaptive delay threshold is proposed according to exponential method. For real-time traffic, the delay is closely related to the packet loss rate, and the delay threshold is modified adaptively according to the real-time packet loss rate. In order to ensure real-time traffic throughput, improve the delay and packet loss rate index, and improve the fairness of the same service. Based on the real-time scheduling method, a two-layer scheduling scheme based on QoS is improved. The upper layer of the improved scheduling algorithm uses one LTE frame (10 TTI, transmission intervals) as the unit to calculate the amount of data transmitted in a wireless frame. The lower layer scheduling takes a TTI as the period, adopts different methods to schedule different services, applies PLR-D method to real-time services, and uses PF (Proportional fair, proportional fair scheduling for non-real-time services, and introduces the balance function between them. Using closed-loop structure to adjust fairness between different services. The system-level simulation platform of LTE mobile communication system is established, and the simulation experiment is carried out. The PLR-D method is compared with other methods to verify the effectiveness of the new method in improving the fairness of real-time traffic on QoS and between services. By comparing the improved two-layer scheduling scheme with the classical multi-service scheduling scheme, it is verified that the new method can improve the throughput of non-real-time traffic while reducing the packet loss rate and delay of real-time traffic. The fairness between real-time and non-real-time services is guaranteed by this scheme.
【學位授予單位】：南京郵電大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN929.5

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本文編號：2453840