LTE系统中基于QoS的多业务调度机制研究
发布时间：2019-04-04 13:01
【摘要】：LTE(Long Term Evolution,长期演进)下行资源调度是保证LTE移动通信系统质量的关键技术。目前移动终端实时业务对QoS(Quality of Service,服务质量)的要求日益提高,在有限的频谱资源下,如何保证实时业务的QoS,提高用户体验质量,同时保障非实时业务的吞吐量,以及二者之间的公平性,是值得研究的重要问题。本文在研究分析了一些经典调度方法基础上,根据指数方法提出一种基于丢包率自适应时延阈值的实时业务调度方法PLR-D。对于实时业务,时延与丢包率是紧密相关的,根据实时丢包率自适应修改时延阈值。使得在保证实时业务吞吐量基础上,提升时延与丢包率指标,并提高同种业务之间的公平性。在实时调度方法基础上,改进了一种基于QoS的两层调度方案。改进的调度算法上层以一个LTE帧(10个TTI,传输间隔)为单位进行一个无线帧内的传输数据量计算;下层调度以一个TTI为周期,对不同业务采取不同方法进行调度,对实时业务运用PLR-D方法、对非实时业务使用PF(Proportional fair,比例公平调度)方法,并在两者之间引入平衡函数,利用闭环结构调节不同业务之间的公平性。建立了LTE移动通信系统的系统级仿真平台,并进行了仿真实验。通过PLR-D方法与其他方法对比实验,验证新的方法在提高实时业务QoS上和业务之间公平性上的有效性。通过将改进的两层调度方案与经典的多业务调度方案对比实验,验证新的方法在降低实时业务丢包率、时延的情况下,同时提高了非实时业务的吞吐量。验证了该方案对实时和非实时业务之间公平性的保障。
[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.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
本文编号：2453840
[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.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5
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