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平滑逻辑信道子载波排序和子载波删除可以提高差分空频编码OFDM的性能,但是导致系统频谱利用率的下降。文中提出一种改进的差分空时频编码的方案,在一个OFDM符号内采用平滑逻辑信道进行空频编码,对于删除的子载波在相邻的OFDM符号间进行差分空时编码。研究结果表明,这种改进的空时频编码OFDM系统和平滑逻辑信道空时编码OFDM系统对比提高了频谱利用率,而没有明显的性能损失。
Smoothing of the logical channel subcarrier ordering and subcarrier deletion can improve the performance of the differential space-frequency coded OFDM but lead to a decrease of the system spectrum utilization. In this paper, an improved scheme of differential space-time-frequency coding is proposed. In one OFDM symbol, a smoothing logical channel is used to carry out space-frequency coding. For the deleted sub-carriers, differential space-time coding is performed between adjacent OFDM symbols. The results show that the improved space-time coded OFDM system and the smoothed logical channel space-time coded OFDM system improve the spectrum utilization efficiency without obvious performance loss.