A Research Of Packet Scheduling Algorithm In Mobile Communication System

Nowadays digital trunking communication has developed rapidly. Traditional voice service has been unable to satisfy the demand of systems traffics. The systems traffics has expanded to multimedia services, which means trunking communication system bandwidth has been increasingly demanding. Meanwhile, TD-LTE(Time Division Long-term evolution) is the representative of the fourth generation of mobile communications, which has been commercialized in the country and popular in communications companies and communications systems. Therefore, the implementation of digital trunking communication based on TD-LTE will not only make an agreement with communications companies,but also satisfy the bandwidth of trunking communication system.Packet scheduling, as one of the key technologies of radio resource management in the broadband multimedia trunking system based on TD-LTE, is in charge of allocating radio resources to users reasonably and fairly. The Effective packet scheduling algorithms can not only allocate radio resources to users efficiently, but also satisfy the requirements of QoS(Quality of Service). It is one of the important technologies to improve system performance.This article will focus on broadband multimedia trunking system based on TD-LTE and analyse the system from two aspects. They are software development for system protocols and packet scheduling algorithm. Software development includes design and implementation for random access control module and automatic repeat request module. Packet scheduling algorithm refers to the algorithm applied in scheduling module of system for real-time traffics.Firstly, this article introduces the background and significance of research, including research status of packet scheduling algorithm and digital trunking communication. Then this article presents the architecture of broadband multimedia trunking system and the protocols of important system interfaces, summarizes the function of MAC layer and RLC layer, the features of system QoS, and so on.Secondly, this article will focus on the research of packet scheduling algorithm, describes the process of scheduling module in detail, and summarizes the important systemic factors considered by scheduling module. Then this article introduces the classic packet scheduling algorithms, such as PF, and improved algorithms to satisfy QoS of real-time traffics, such as M-LWDF. Finally, this article compares the performance of algorithms.Thirdly, this article summarizes the issues of classic packet scheduling algorithms for real-time traffics, and proposes a novel packet scheduling algorithm based on the issues of classic algorithms, mathematical analysis and simulation. The algorithm can not only improve the performance of system, but also solve the issues. Finally, according to the simulation, this article verifies the design of algorithm and achieves the goal.Finally, according to the research for the protocols of system and the architecture of system, this article implements the design and development of random access control module in MAC layer and automatic repeat request module in RLC layer. In addition to completing the function of modules, efficient and maintenance should also be consided.