一种改进的差分空时频编码OFDM系统设计

Design on Improved Differentially Space-Time-Frequency Coded OFDM System

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。

A smooth logical channel is an efficient method to improve the performance of differentially space-frequency coded orthogonal frequency division multiplexing （OFDM） by re-sorting subcarriers and pruning subcarriers. However, it reduces the spectrum utilization of the space-frequency coded OFDM systems. An improved differentially space-time-frequency coded OFDM method is presented in thispaper. The space-frequency coding over smooth logocal channel is implemented within per OFDM symbol and the differentially space-time coding is realized between two successive OFDM symbols. The results show that the spectrum utilization of space-time-frequency coded OFDM is higher than that of space-frequency coded OFDM, and this improved system also has no distinct performance deterioration.