一种抗延时失真的并行传输系统分析

Study of a delay-distortion-resistant parallel transmission system

针对移动通信系统中存在的多径延时扩展问题,研究了一种具有很多相互重叠子信道的并行正交调幅数据传输系统。该系统利用大量的子信道使得总的信号速率能够非常接近给定频带的奈奎斯特速率。在传输媒质存在延时失真的情况下,详细分析了并行数据传输系统的性能。结果表明并行系统的失真与子信道数目的平方成反比,从而说明了该系统具有抵抗延时失真的作用。此外,使用半余弦滚降的系统性能要比使用余弦滚降的好,改变解调相位还可以大大改善系统性能。

For the multipath delay spreading problem existing in the mobile communication systems, a parallel quadrature AM data transmission system with a number of overlapping subchannels is investigated. The system can make the total signaling rate very close to the Nyquist rate of given frequency band through the use of a lot of subchannels. In the presence of delay distortion of the transmission medium, the performance of the parallel data transmission system is analyzed. The results show that the distortion of the parallel system is inversely proportional to the square of the number of subchannels which illustrates the effectiveness of the system in combating delay distortion. In addition, the performance is better than that of full cosine roll-offs when half cosine roll-offs are used, and the system performance can be substantially improved by altering the demodulating phase.\;