改进的多用户OFDM系统子载波和比特分配算法

针对多用户正交频分复用（OFDM）系统资源分配问题,提出了一种改进的基于边缘自适应（MA）准则的子载波和比特分配算法。在采用比例公平准则为每个用户分配子载波集合基础上,以用户速率最大者-最小者（Max-Min）子载波交换为原则进行子载波调整,使用户功率递减同时兼顾用户的公平性;通过对信道状态信息进行判断,利用贪婪算法将用户子载波分配的比特取整,以实现系统功率最小化。实验结果表明,本文提出的改进次优算法的计算复杂度较传统分步算法稍高,但仍远低于最优算法,其系统性能得以提升,且接近最优算法。

An improved subcarrier allocation and bit loading algorithm for multiuser OFDM system

A scheme of Margin Adaptive（MA）-based improved subcarrier and bit allocation was proposed for resource allocation in multiuser Orthogonal Frequency Division Multiplexing（OFDM） system.In order to decrease the transmit power of users and guarantee the fairness principle,subcarrier exchange for user Max-Min transmission rate was adopted as the principle,besides employing proportional fairness principle to allocate subcarriers for each user.Then,the bit was rounded by the greedy algorithm with the channel state information judgment,to obtain the minimized transmission power of the system.The analysis and simulation results show that the computational complexity of the proposed improved suboptimal algorithm is a little higher than that of the traditional step-by-step algorithm,but when compared to the optimal algorithm,the proposed algorithm is of almost the same performance and a far lower computational complexity.