多用户OFDM系统中一种新颖的自适应功率分配方案

A New Adaptive Power Allocation Scheme for Multiuser OFDM Systems

摘要:

针对多用户正交频分复用(OFDM)系统自适应资源分配的问题,提出了一种新的自适应子载波分配方案。子载波分配中首先通过松弛用户速率比例约束条件确定每个用户的子载波数量,然后对总功率在所有子载波间均等分配的前提下,按照最小比例速率用户优先选择子载波的方式实现子载波的分配；在功率分配中提出了一种基于人工蜂群算法和模拟退火算法(ABC-SA)相结合的新功率分配方案,并且通过ABC-SA算法的全局搜索实现了在所有用户之间的功率寻优,同时利用等功率的分配方式在每个用户下进行子载波间的功率分配,最终实现系统容量的最大化。仿真结果表明,与其他方案相比,所提方案在兼顾用户公平性的同时还能有效地提高系统的吞吐量,进而证明了所提方案的有效性。

Abstract:

To deal with the adaptive resource allocation problem in multiuser OFDM systems, a new adaptive subcarrier allocation scheme is proposed. In the subcarrier allocation process, the subcarrier number of every user is firstly determined by relaxing the proportional constraint of the user rate, and then under the premise that the total power is equally allocated in all the subcarriers, the subcarrier allocation is realized by the method that the minimum proportion rate user has the priority to be chosen into the subcarriers. A novel artificial bee colony-simulated annealing (ABC-SA) power allocation scheme based on artificial bee colony algorithm and simulated annealing algorithm is proposed in the power allocation, and the power optimization among all users is achieved by the global search of the ABC-SA algorithm, in addition, the power allocation among the subcarriers of each user is carried out by the method of the equal power allocation and the maximum capacity of multiuser OFDM systems is ultimately obtained. Simulation results show that the proposed scheme, compared with other schemes, can effectively improve the throughput capacity of the OFDM system while taking into account the fairness of users. Therefore, the effectiveness of the proposed scheme is verified.