Research On Adaptive Resource Allocation For OFDM System

Today, mobile communication has spread to every corner of the world, andthe users are around the world, which for the future development of mobilecommunications presented more challenges. The goal of future mobilecommunication is to satisfy the users overall demand of a higher rate, the betterquality and more business types. However these requirements of standards andthe increasingly scarce resources in the wireless communication system are verycontradictory, so how to manage and adjust the existing wireless resourcereasonably will be a significant research subject.The principle of orthogonal frequency division multiplexing technology is todivide the original communication channel into several sub channels, the subchannels can effectively resist various interference from the channel through theorthogonal characteristic between each other, and improve the spectrumefficiency at the same time. Adaptive resource allocation technology, that is,according to the different requirements of each user and the real-time stateinformation of each sub channel, the allocation of various resources (sub-carriers,the total power, bits) is adjustable, and ultimately achieve the effect of channelresources are being used reasonably.This paper first introduces the nature of the wireless channel, and theprinciple and the implementation of OFDM systems, as well as the main technicalfeatures of adaptive resource allocation are described in detail. Then, this paperfocuses on the adaptive resource allocation problem and does the related researchfrom single-user and multi-user systems two aspects. In a single-user system,mainly studies the practical filling algorithm and greedy algorithm the two kindsof typical algorithm, and on this basis, a kind of bit allocation in single usersystem which can reduce the complexity of the algorithm is designed in this paper.The experimental results show that: the proposed algorithm is very close to the other two kinds of optimization algorithm on the result of bit allocationdistribution, but the complexity of the proposed algorithm significantly reducedin this paper. In a multi-user system, this paper mainly discusses the subcarrierallocation problem under the rule of RA. Based on the analysis of the basicprinciples of the traditional artificial fish swarm algorithm and cultural algorithm,a kind of artificial fish swarm algorithm with cultural evolution was designed inthis paper. With the performance simulation and the comparision of AFS and shenalgorithm, the experimental results show that: AFSAC can effectively improvethe complexity of the algorithm, and make the algorithm converges faster thanthe AFS algorithm, under the rule of RA a bigger system transmission rate isobtained.