Research On Wireless Packet Scheduling In TD-LTE System

In the LTE system, eNodeB is responsible for managing the uplink and downlink resource packet scheduling. Compared to the wireless communication systems, in which packet scheduling is controlled by the RNC, packet scheduling in the LTE system can choose proper MCS and code rate in a timely manner according to channel conditions and fading characteristics with adaptive modulation and rate change, while reducing system latency and memory requirements of UE.Compared to the wireless communication systems, in which packet scheduling is controlled by the RNC,Meanwhile, TD-LTE system has unique wireless frame structure, HARQ management, and resource allocation type. In resource packet scheduling, the influence of these TD-LTE system characteristics should be fully considered.In addition, under normal circumstances, the same UE may run multiple applications at any time, including both real-time services, such as voice conversation, video conversation(streaming media), and a variety of non-real-time services, such as TCP-based chat, FTP, P2P file sharing. At the same time, each radio bearer corresponds to a specific QoS Class identifier (QCI), which contains the minimum guaranteed bit rate, priority, packet delay budget and acceptable packet loss rate.How to reasonably allocate resources for a variety of service with different bandwidth requirements, different time delay requirement and different QoS levels to meet their basic service needs, and do its best to improve the overall network throughput and spectrum efficiency, meet as many users expectations as possible and consider the quality of service(QoS) requirements for each service, are the tasks of the packet scheduling algorithm.This paper focuses on the packet scheduling algorithm based on TD-LTE system level simulation platform. First, the TD-LTE system simulation platform is introduced. Second the classical packet scheduling algorithm and its evaluation protocol is classified discussed. Then the improvement plan of packet scheduling in time-frequency domain is given coordinating with characteristics and requirements of the TD-LTE system including ICIC technique. Finally the performance of scheduling algorithms is analyzed by simulation. Meanwhile, the paper also provides a new integrated QoS-oriented packet scheduling algorithm, and validates it on the simulation platform. The main purpose of the new packet scheduling algorithm is to give priority to the data transmission of the users with high QCI level, which is based on the actual needs of the network, and to minimize the number of retransmission, while taking the fair into account.