中文摘要：

这篇文章学习 downlink 副载波任务问题最大化易于的率和能力在直角的频率部门 multiplexing (OFDM ) 总计力量和比例的率限制系统。以前的算法假设起始的力量在所有副载波上是同等地分布式的。路径损失的存在再使假设不正确。这篇文章建议充分利用路径损失和率比例信息改进率和能力的一个新奇副载波任务算法。建议算法根据路径损失和不同用户的率比例决定最佳的起始的力量分配，以一种贪婪方式把副载波分到用户，然后交换在获得更公平的率分发的用户之间的副载波。模拟结果证明建议算法近似完成静态的赋值计划的两倍能力，并且面对不同路径损失和比例的率要求比以前的副载波赋值算法获得更好的性能，例如固定频率乐队途径。

英文摘要：

This article studies downlink subcarrier assignment problem to maximize rate-sum capacity subject to total power and proportional rate constraints in orthogonal frequency division multiplexing （OFDM） systems. Previous algorithms assume that the initial power is equally distributed over all subcarriers. The presence of path loss makes the assumption not correct any more. This article proposes a novel subcarrier assignment algorithm which makes full use of path loss and rate proportionality information to improve rate-sum capacity. The proposed algorithm determines optimal initial power allocation according to path losses and rate proportionalities of different users, assigns subcarriers to users in a greedy fashion, and then exchanges subcarfiers between users to obtain fairer rate distribution. Simulation results show that the proposed algorithm approximately achieves double the capacity of static assignment schemes, such as fixed frequency band approach, and obtains better performance than previous subcarrier assignment algorithms in the presence of different path losses and proportional rate requirements..