Research On Resource Allocation Algorithms For Multi-User OFDMA Systems

The next-generation mobile communication systems are required to provide high data-rate, high reliable transmission and guarantee end-to-end QoS. OFDMA system is considered to have the ability to processing multimedia services, which have different QoS requirements, so the scheduling algorithm mush provide an integrated QoS mechanism。This thesis mainly studies the main key problem, namely resource allocation algorithm with QoS satisfaction.Firstly we make a summarization of technical reports related to resource allocation in 3GPP LTE, including scheduler architecture, scheduler function, scheduling factors, scheduling classification, and then we make a pilot study on downlink transmission scheme of OFDMA and system parameters choice, getting the effect of which to the system performance by simulation.Then we do research on system resource allocation with QoS satisfaction, by introducing "channel-aware and queue-aware" scheduling algorithm-Max Delay Utility (MDU) algorithm, user equipments with different channel qualities may have similar delay QoS satisfaction, then we make some improvement to this algorithm-considering using the receiving throughput as one of the resource allocation factors, simulation results demonstrate that the improved algorithm can effectively improve the throughput QoS satisfaction to each user.At last we make some study on QoS satisfaction for heterogeneous traffic, by introducing traffic power factor to the MDU algorithm, different traffic has different priority, simulation results demonstrate that MDU algorithm can also perform well in multi-traffic system and provides delay and throughput QoS satisfaction to different traffics.The low implementing complexity and high efficiency of MDU algorithm make it one of the solutions of resource allocation in future IP-based packet switching network.