The Research And Implementation Of Real-time Services Scheduling Mechanism In LTE System

With the continuous development of communication technology, there are more and more real-time multimedia services in the LTE system. However, the increasing requirements of the quality of service of the real-time multimedia services present a great challenge to the existing scheduling algorithms. It is very necessary to conduct a further study on the existing scheduling algorithms. The core issue of LTE radio resource scheduling is that the scheduling algorithm not only meets the QoS requirements, but also makes the radio spectrum resources used efficiently and ensures the fairness among users. This article is dedicated to solve this issue.On the basis of the existing academic research about the scheduling algorithm, and combining the author’s internship experience about LTE scheduling mechanism in a communication equipment manufacturer, this paper proposes a new scheduling algorithm for LTE downlink real-time multimedia services. The new scheduling algorithm is named as Approximate Deadline Constraint Scheduler(ADCS). This new scheduling algorithm considers the users’ channel quality and the delay of the users’ first packet to be transmitted in the buffer queue. In order to further reduce the time delay and packet lost rate, the difference of the delay and the users’ data packet delay threshold is introduced into the new scheduling algorithm specially. Meanwhile, in order to ensure the fairness among the users, the new scheduling algorithm also takes the users’ data packet instantaneous bit transmission rate, average bit transmission rate and target bit transmission rate into account. By using LTE-Sim simulation platform, M-LWDF, EXP/PF and ADCS are simulated. The results show that comparing with M-LWDF and EXP/PF, ADCS has a very good improvement in the aspects of the users’ packet loss rate, the users’ data packet time delay and the spectral efficiency. When the number of the users in the system is 30, ADCS improves 2.44% than M-LWDF in the spectral efficiency, for Video service: the time delay decreases 8%, and for VoIP services: the users’ packet loss rate decreases 16% and the time delay decreases 40%.In order to put ADCS on the specific equipment, relying on the communication equipment manufacturer’s hardware and software, this paper carries out the proposed scheduling algorithm design and implementation through the C++ programming language. When telecom operators or communication equipment manufacturers want to apply this scheduling algorithm, they can refer to this paper.