Research On Multi-User Scheduling Algorithms In Relay-Aided Cellular Network

Applying relaying to the OFDM-based next-generation mobile communication system brings more flexibility in resource allocation. The prototype of next generation mobile communication network based on both OFDM and relaying has been highly expected. Both IEEE and 3 GPP, two current biggest organizations in the future 4G standard, regard relaying as the key technology in their discussions. In order to fully explore the potential of relaying in the OFDM-based cellular network, efficient radio resource management is to be researched.Firstly this dissertation describes the development of relaying and gives a detailed description of the classification and typical application scenarios of relay station. Secondly multi-user scheduling algorithms in radio resource management were studied in two aspects: 1)Enhanced scheduling algorithms under both centralized and distributed mechanism are proposed respectively based on the traditional multi-user scheduling algorithms.2)One new scheduling algorithms over backhul link under distributed mechanism are proposed according to users'classification based on users'queue information. Finally a system-level simulation platform based on the typical scenario in 3 GPP LTE-Advanced is built to verify the proposed algorithms above and conclusions can be drawn from the simulation results as follows:First of all, algorithms achieve different performance under different mechanism:Round Robin Algorithm achieves the same performance under two mechanisms; Proportional Fair Algorithm performs better under centralized mechanism; Max Carrier-to-Interference Algorithm achieves higher throughput under distributed mechanism than under centralized mechanism but lower than in traditional cellular networks. Secondly, new backhaul scheduling algorithms can be applied to allocate resources over backhaul link reasonably with less overhead. If the performance of relay-aided cellular network is confined to the backhaul link, proposed algorithms can bring significant gain in the aggregated cell throughput at the cost of some certain degree of user fairness. But if the performance is confined to the access link, different backhaul scheduling algorithms will result nearly the same aggregated cell throughput.