| LTE(Long Term Evolution)has made two major improvements on previous communication systems.First,the networking architecture becomes flat.After network flattening,the base station becomes the only network element on the access side of wireless network,which strengthens the decisive position of base station in downlink control.Secondly,the transmission mode is ip-based,that is,the whole IP mode is adopted to transmit data packets,so that voice and data services are transmitted using IP packet mode,thus improving the transmission rate of the system.These two characteristics of LTE system make many previous scheduling algorithms no longer applicable,and the research on grouping scheduling algorithm of LTE system has been developed since then.With the diversified development of network services,users have higher and higher requirements on QoS(Quality of service)of network services.As a network service provider,how to improve the Quality of users' network experience and improve the utilization rate of resources under the limited spectrum resources is an important issue worthy of in-depth research.Based on the study of LTE system are analyzed comparatively classical several packet scheduling algorithm and its improved algorithm,first of all,according to the characteristics of non-real-time service designed for non-real-time business cache priority packet scheduling algorithm,algorithm within a certain time of the idea is to group the number and size of the cache as a decision factor to join algorithm of scheduling priority formula,improve the system throughput,reduce the packet loss rate,and improve the fairness between the same business.Considering the future network development,voice services have been included in the LTE system,the design for the real-time and non-real-time business mix of packet scheduling algorithm is very necessary,so this article is designed to improve the scheduling scheme based on M-LWDF,real-time and non-real-time business according to the QoS level identification QCI(QoS Class Idenifier)scheduling,the formula of classification to distinguish business in real time on the calculation of the time factor and guarantee the bit rate included in the calculation of the priority of QCI function,for the real-time business,adding the priority function of non-guaranteed bit rate on the basis of PF algorithm can ensure that the priority of real-time service is higher than that of non-real-time service,reduce system delay and packet loss rate and increase system throughput,but at the expense of a small amount of fairness.Finally,aiming at the two improved algorithms,LTE system-level simulation platform was established,and parameters were set for simulation comparison experiments to verify the effectiveness of the proposed algorithm. |
