正交频分多址系统中最低速率限制下的自适应载波分配

针对用户有最低传输速率要求的正交频分多址系统中,传统资源分配算法频谱利用率低的问题,提出了一种自适应载波分配算法.该算法根据用户最低传输速率的要求、信道状态和当前载波分配状况,确定子载波分配给用户的效用,进而将子载波分配给可以带来最大效用的用户.该算法综合考虑了效率和公平性,从而显著改善了系统性能.仿真结果表明,当用户数不超过系统负载时,与效率和公平分开考虑的算法相比,所提出的算法频谱效率可提高10%,系统负载在同样中断概率下可提高60%.

Adaptive Sub-Carrier Allocation for Orthogonal Frequency Division Multiple Access Systems with Minimum Transmission Rate Request

Focusing on the problem that traditional resource allocation algorithms result in low spectrum efficiency,an adaptive sub-carrier allocation algorithm was proposed for orthogonal frequency division multiple access systems with minimum transmission rate request.In the algorithm, the utility value of each sub-carrier that can be achieved by different users is first evaluated based on users' minimum transmission rate request,the channel state and the current sub-carrier allocation state.Then,the sub-carrier is allocated to the user,who can achieve the maximum utility value.As both efficiency and fairness are taken into account in the algorithm,the performances of the system are improved remarkably.Simulation results show that,compared with algorithms which consider efficiency and fairness separately,when the number of users is within the system load,the frequency efficiency of the proposed algorithm increases by 10% and the system load within the same range of outage probability increases by 60%.