多用户OFDM系统中子载波和比特联合分配算法

研究了多用户正交频分复用(OFDM)系统中的自适应调制算法。针对现有算法将子载波和比特分配分开考虑、优化效率不高且没有考虑每个用户的性能要求不同的不足,提出了子载波和比特联合分配的自适应算法。在满足每个用户性能要求的条件下,该算法自适应分配子载波和比特使系统的发射功率达到最小,而且每个用户能公平利用系统资源。仿真结果显示:该算法计算速度快,性能大大优于贪婪算法,和最优算法相比,性能仅相差0.3 dB。

Joint sub-carrier and bit allocation algorithm for multi-user OFDM systems

The adaptive modulation in multi-user OFDM systems is investigated.By handling the sub-carrier and bit allocation separately the existing algorithms have the drawbacks of poor performance and not considering the application conditions that every user has its own bit error rate.A joint sub-carrier and bit allocation algorithm is proposed.Under the bit error rate constraint of each user,the aim is to minimize the transmitting power by allocating the sub-carrier and bit adaptively while achieving proportional fairness among users.Simulation results show that the performance of this algorithm is better than that of the greedy algorithm,and only 0.3 dB inferior to that of the optimal algorithm,but its computational complexity is reduced dramatically.