Research On Resource Allocation For LTE Downlink System

LTE is short for Long Term Evolution. It is the largest research project on new techniques initiated by 3GPP. This LTE technique bases on OFDM/FDMA, and LTE feasibility study at this stage mainly concentrates in the downlink OFDMA and uplink SC-FDMA.This paper focuses on LTE downlink OFDMA system. First, it introduces the history of the development of mobile communications systems and LTE system research background, and then studys on the technical characteristics of OFDMA system. Besides, there is in-depth discussion of the related issues about resource allocation in wireless system, such as fairness and QoS.Chapter 4 presents communications system simulation, including link-level simulation and system-level simulation, and introduces the BLER equivalent algorithm to reduce the complexity of system simulation. The author has verified the accuracy of the algorithm by simulation. Chapter 5 is the most importment part of this paper, through the creation of system model and simulation realization, the parameters that affect system performance are discussed and analysed, such as different scheduling algorithms and different HARQ schemes. As more and more services have their own QoS requirements, such as transmission time delay, the scheduling strategy of downlink system is also studied, focusing on the simulation of the MDU subcarrier allocation algorithm. By comparison, to the PF algorithm, we can find that the algorithm can effectively guarantee the user's QoS of time delay.