Design of digital pulse-position modulation system based on minimum distance method

Abstract

Pulse-position modulation (PPM) is a form of signal modulation in which M message bits are encoded by transmitting a single pulse in one of 2M possible required time shifts. It is primarily useful for optical communications systems, which tend to have little or no multipath interference. PPM is currently being used in fiber-optic communications, deep-space communications, and continues to be used in R/C systems. In this paper, we simulate a relatively complete process of PPM transmission. We generate the basic form of PPM using random sequences and then we visualize the impact of AWGN on the signal on the PPM real plain. Then we use the minimum distance discrimination method to demodulate the signal. Details about errors are collected as well to illustrate the point. At last, we imitate the PAM system to calculate the BER.