研究了基于正交空时分组码的多用户OFDM系统的自适应子载波分配算法.首先从性能角度出发,在保证用户误码率约束的前提下,以总的发射功率最小为目标,推导了具有普遍意义的OSTBC—OFDM的子载波分配通式.考虑到实际应用系统中效率与公平的折中,对各个用户定义相应的速率约束,以增加功率最小为原则,给出了改进的兼顾公平的子载波分配算法的具体步骤.数值仿真结果证明,自适应子载波分配能改善OSTBC-OFDM系统的误码率性能,且兼顾公平的算法需要一定的性能损失为代价.
An adaptive subcarrier allocation algorithm for multiuser OSTBC-OFDM system is discussed in this paper. Aimed at minimizing the overall transmit power subjected to meet the target BER, an adaptive subcarrier general allocation algorithm with effficiency-priority is proposed. To achieve a desirable tradeoff between efficiency and fairness, all users are given a guaranteed transmission rate. An amendatory four-step algorithm with fairness constraint is described. Simulation results show that the proposed algorithms can improve BER performance of the OSTBC-OFDM system.