超奈奎斯特速率(FTN)传输进展

Abstract

在数字通信系统中，奈奎斯特准则指出，为了实现无码间干扰的传输，符号速率必须满足奈奎斯特准则。然而1975年Mazo发现在带限加性高斯白噪声信道中，当码元速率超过奈奎斯特速率在25%以内时，信号的归一化最小欧式距离并不会减小，并称为Faster-Than-Nyquist signaling (超奈奎斯特，FTN)。本文首先介绍FTN传输的发展历史，分析FTN系统的Mazo限，并对FTN传输以及奈奎斯特速率下的限制信道容量进行比较。从仿真结果可以看出，当脉冲存在过剩带宽时，FTN传输可以得到比奈奎斯特速率下更高的信道容量。 In digital communication system, the Nyquist criterion states that the symbol rate must satisfy the Nyquist criterion in order to achieve transmission without intersymbol interference. However, in 1975, Mazo found that in band-limited Additive White Gaussian Noise channel, the normalized minimum Euclidean distance does not decrease when the symbol rate exceeds within 25% of the Nyquist rate and name it as Faster-Than-Nyquist signaling (FTN). In this paper, we first introduce the history of FTN transmission, analyze the Mazo limit of FTN system, and finally compare the capacity of FTN and Nyquist rate transmission. Simulation result shows that when the transmitted pulse has excessive bandwidth, FTN transmission can achieve higher capacity than transmission under Nyquist rate.