抗信道快变的酉空时星座设计

Unitary Space-Time Constellation Design Against Channel Rapid Changes

分析了移动台以不同大小速率移动时,信道衰落系数在同一分组长度内的快变性。通过计算机仿真分析发现酉空时码的误码率随着信道衰落系数自相关函数的减小而恶化,且随分组长度增大而加深恶化。在系统化酉空时星座设计方法的基础上,提出了一种抗信道快变的酉空时星座设计方案。仿真结果表明该方案可有效地缓解由于信道快变而引起的误码率恶化问题。

The variation of channel coefficients autocorrelation in a block time is analyzed when the mobile is assumed to travel at different speed and unitary space-time modulation is employed in the communication system. Computer simulation shows the block error rate of unitary space-time modulation increases with the decreasing of autocorrelation of channel coefficients in a block time. Furthermore, the bigger the block is, the worse the block error rate will be. A new method of unitary space-time constellation,which can improve the influence on block error rate by fast fading, is designed based on a systematic method. Simulation experiments show that the block error rate of the new scheme is much lower than that of the old one when the mobile travels at a relatively high speed.