多径瑞利衰落信道下AQAM系统最佳信噪比门限值的研究

Research of the Optimum SNR Thresholds of AQAM System Over Multi-path Rayleigh Channel

自适应调制根据瞬时信道信噪比选择适当的调制方式,能够改善系统的BER性能以及平均吞吐量性能。在常用于高速移动环境的六径瑞利衰落信道模型下,研究自适应调制系统的最佳信噪比门限值,使系统的平均吞吐量最大,同时保证了目标BER性能,得到的最佳门限值可以用于ITU-R M.1225 Vehicular Test A模型的自适应调制系统。

Adaptive modulation techniques can improve the BER （bit error rate） performance or the average throughput by employing a suitable modulation mode depending on the instantaneous channel SNR （signal-to-noise ridio）. In this paper the optimum SNR thresholds over a 6-path Rayleigh channel are derived, which shows a superior BPS （bit per symbol） throughput performance while maintaining the target average BER. The 6-path Rayleigh channel is often applied to mobile environment with high-speed. The results achieved in this paper can be applied to the adaptive modulation system with the channel of ITU - R M. 1225 Vehicular Test A mode.