Abstract: A multiuser rate adaptive subcarrier allocation algorithm with a parameter α to control the capacity and fairness is proposed in the paper.In the algorithm，equal power distribution is assumed across all the subcarriers.The αN subcarriers are allocated based on the maximum value of channel response.Then the remaining subcarriers are allocated based on the minimum ratio of user’s capacity to the proportional fairness has the priority of selecting subcarriers.After subcarrier allocation，the subcarriers power is adjusted with water-filling algorithm.Simulation results show that capacity and fairness can be both achieved with the proposed subcarrier allocation.

Key words: Orthogonal Frequency-Division Multiplexing（OFDM）, resource allocation, multiuser diversity, proportional fairness

摘要： 提出了一种在多用户OFDM系统中总发射功率和误码率限定的条件下，系统总数据容量最大化的子载波分配算法。针对已有算法对数据容量和公平性兼顾较差的情况，通过引入比例公平控制参数α，把子载波分配分为两部分，首先对所有用户的信道增益降序排列，从中选择αN信道增益较好的子载波进行分配，然后对剩余的（1-α）N个子载波按比例公平的原则进行子载波分配。第一步可以获得较粗糙的比例公平，但可以获得较大的数据容量，通过第二步进一步调整比例公平。可以根据实际需要选择合适的α。子载波分配完毕后，采用注水算法调整子载波间功率分配。通过仿真显示该文算法数据容量得到提高的同时很好地保持了用户间的比例公平。

关键词: 正交频分复用, 资源分配, 多用户分集, 比例公平