Research Of Sub-carrier And Power Allocation Algorithm In OFDM Systems

Orthogonal Frequency Division Multiplexing (OFDM) technology, which possesses of many advantages, such as the resistance against the noise and the multipath interference, and high spectrum usage, and so on, is considered as a potential candidate for the physical layer of the future mobile communication.Firstly, some relevant fields and knowledge are introduced and illuminated, which mainly include the evolutive of modern communication technology, the introductions of RRM, the propagation properties of wireless channel, the introductions of OFDM technology, the multiuser OFDM technology, the basic knowledge of convex optimization, and so on. And channel models and the BER of OFDM system in multi-path Rayleigh fading channel are analysed and simulated.Then, considering the demands of system performance, low computational complexity, fairness and QoS integratedly and comprehensively, the important and main problem of the theme, which is dynamic sub-carrier and power allocation algorithm in multiuser OFDM systems, is detailedly expounded. And being based on the existing and heuristic algorithms at home and abroad, two optimization problems are mainly discussed.â‘ Rate Adaptive (RA) resource allocation, which is proposed anew modified algorithm------TSA algorithm;â‘¡Margin Adaptive (MA) resourceallocation, which is also proposed two new modified algorithms------algorithm Aand algorithm B. Then the performance of eight methods is simulated using Matlab communication simulation software, and these simulation results is analysed and compared. The conclusion is that the performance of three modified algorithms is better than other existing schemes.Finally, the researchful schemes, results and their innovations, advantages and disadvantages are concluded. For the future multicarrier wireless systems, it's suggested that there are still many fields and problems left for further research.