Research On Downlink Resource Scheduling Algorithms In LTE

In recent years, with the wide spread of the LTE network, the users of LTE also have increased, which requires the scheduler to function reasonably and smartly. Therefore, the experts have done a lot of research about the resource scheduling. This article is based on a national project ?A Research On The Evalution And Projection Of LTE Dedicated Broadband Mobile Communication Network?. Under this circumstance, this article lay the importance on the design of the LTE downlink scheduling algorithm. This article introduces the architecture of the LTE system and the way of the data transmission in the LTE protocol stack. Then this article learns about the radio resource management module. After knowing about the function of the radio resource management module and the strategy of the downlink scheduling, this article analyzes the factor that the LTE downlink scheduling algorithm should consider and introduce the criterion of the evaluation of the downlink scheduling algorithm. This article also analyzes the classical downlink scheduling algorithms, and introduces two QoS support scheduling algorithm in hybrid networks.The first scheduling algorithm is based on a two-level scheduling algorithm for QoS support in the downlink of LTE network. This article analyzes the principle of operation and the merits and faults the algorithm. According to the Algorithm the real-time traffic can enjoy preferential service. The non real-time traffic won?t be scheduled until the real-time traffic finishes their data transmission. Then this article modifies the two-level scheduling algorithm, that is raising the priority of the non real-time traffic and the traffic with good channel quality, aiming at increasing the throughput of the non real-time traffic as well as controlling the delay of the real-time traffic to adapt to the coexistence of the non real-time traffic and the real-time traffic in the LTE networks.This article also combines the advantage of the token bucket algorithm of the control of the throughput of traffic and the advantage of the EDF scheduling algorithm to limiting the delay of traffic, to introduce a algorithm to schedule radio resource on hybrid network, and the algorithm makes use of the knowledge about the multiple matching of bipartite graph of graph theory, aiming at guaranteeing the minimum throughput of the non real-time traffic with respect to fairness across different network flows as well as controlling the delay of the real-time traffic.After modifying and extending the LTE system-level simulator developed by Technical University of Vienna with extensive use of the object-oriented programming capabilities of MATLAB, simulations have been done on the proposed downlink scheduling algorithm with the help of the simulator, and the author figures out the results of the proposed algorithm, the classical algorithm and the algorithm proposed by others, compares them with each other and makes a very thorough analysis to verify the advantage of the proposed algorithm to do radio resource allocation in the hybrid network.