Research On Wireless Resource Scheduling Algorithm Of LTE System Within High-speed Rail Environment

The rapid development of high-speed railway brings more convenience to our life. At the same time, how to ensure high quality communication service for passengers in high-speed environment becomes a hot topic. The LTE as a new generation of mobile communication system, which combines OFDM, MIMO and other advanced wireless technologies, has the characteristics of large bandwidth, high coverage ability and high spectrum efficiency can better meet the growing demand of multimedia service. It has shown great prospects in high speed railway communication system. However, the wireless resource is still limited, the diversity of user services and the particularity of high speed rail environment has increased the challenge of the research on the rational utilization of spectrum resource. If the wireless resource scheduling is unreasonable, the user experience and communication quality will be affected. Consequently, the resource scheduling algorithm is one of the essential technologies in LTE system.Firstly, this paper introduces the characteristics and performance of LTE, describes the network architecture of LTE, the function of each network element and the key technologies in LTE system. Besides, it introduces the resource structure of LTE and three basic types of resource scheduling algorithm in LTE system: RR algorithm, MAX C/I algorithm, PF algorithm, then analyzes and compares the three algorithms.Secondly, this paper mainly studies the resource scheduling algorithm in high-speed railway environment, and a scene of ordinary users and train users co-exist when the train crossing the cell is built. Because of the high speed moving train will bring some special problems such as the Doppler frequency shift, poor channel environment that deteriorate the communication environment of train users and put them into a competitive disadvantage position, which may make them to get wireless resource badly and seriously affect the communication service quality of them. Bases on the analysis of the classical scheduling algorithm which cannot meet the fairness of the train users, a packet scheduling algorithm p-PF which aims to improve the fairness of train users is proposed. The core of the algorithm is to add the number of train users to improve the priority of the train, so as to improve the fairness of the train users.Finally, a performance simulation of the RR algorithm, MAX C/I algorithm, PF algorithm and the improved algorithm p-PF in terms of throughput and fairness is made in this paper. The results show that, the p-PF algorithm is performed better than the other three algorithms in high-speed railway environment, which not only ensure the throughput of the train users, but also effectively improve the fairness of them. Otherwise, in order to further verify the performance of the p-PF algorithm, FTP service and Video service are selected in this paper. And the performance simulation of PF algorithm and p-PF algorithm shows that no matter which types of business, the p-PF algorithm can improve the throughput and fairness of train users.