一种低复杂度的MIMO-OFDM下行链路子载波分配改进算法

针对多入多出正交频分复用( MIMO - OFDM)系统的下行链路,提出一种基于信道状态信息(CSI)反馈的次优子载波分配算法.算法从寻求容量和公平性之间的平衡出发,将提高系统容量作为资源分配的优化目标.该算法首先按照比例公平约束进行子载波初始分配,然后将现行分配给任意两个用户的子载波互换之后计算系统容量,如果系统容量增加,则将子载波在用户间进行交换,否则保持初始分配不变.将子载波在用户间进行迭代调整,直到系统总容量不再增加为止.仿真结果表明,该算法能够很好地保证比例公平约束,有效地提高系统容量,提升效率可以达到贪婪算法的40％左右,对MIMO - OFDM系统中的子载波分配具有一定的参考价值.

An improved sub-carriers allocation algorithm with low complexity for MIMO-OFDM downlink

A suboptimal sub-carriers allocation algorithm based on channel state information(CSI) for the downlink of Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing(MIMO-OFDM) system is proposed in this paper.The tradeoff between fairness and capacity is considered and the purpose of the algorithm is to maximize the capacity of the system.The algorithm firstly implements initial allocation according to the proportional fairness constraint,and then calculates the variety of the system capacity if the sub-carriers allocated to any pair of the users are swapped.If the system capacity is increased,the sub-carriers are swapped,or the initial allocation is kept.The sub-carriers among users are iteratively swapped until the system capacity couldn′t be improved.Simulation result shows that the proposed algorithm can improve system capacity effectively with proportional fairness among users and the capacity increment can reach about 40% of the greedy algorithm.The conclusion has reference value for the sub-carriers allocation in the MIMO-OFDM systems.