Optimal Design Of Pulse Amplitude Position Modulation In Optical Spatial Modulation

Optical Spatial Modulation(OSM)is a transmission technique using multiple light source developed in recent years.Osm is a special multi input multi output technique.It overcomes the problems of multi-input multi-output technology such as interference between channels and laser synchronization.At present,the research of optical spatial Modulation mainly focuses on Pulse Amplitude Modulation(PAM)and Pulse Position Modulation(PPM).For Pulse Position Amplitude Modulation(PPAM),there are few researches in the field of optical spatial modulation.This thesis aims to explore how to improve the error characteristics of traditional PPAM modulation to meet the requirements of intensity modulation/direct det ection.This thesis also introduces the concept of antenna selection in RF communication,and the proposed method can significantly improve the error performance.The specific research contents are as follows:(1)At present,in the field of optical space modulation,the research on PPAM based on optical space modulation is relatively limited.Therefore,this paper makes full use of the advantages of PPM and PAM modulation,and proposes an OSM-PPAM scheme to optimize PPAM modulation in optical space modulati on system.Firstly,the activated light source is selected,and then the location and amplitude of the pulse are optimized using the exhaustive search traversal algorithm.Through in-depth analysis,it is found that OSM-PPAM can effectively improve the transmission rate of optical generalized spatial modulation and reduce the computational complexity.Compared with other modulation schemes,the scheme proposed in this paper can not only guarantee the transmission rate,but also effectively improve the error performance of the system.(2)Three-dimensional joint mapping space modulation technology is proposed to improve the reliability and practicability of the system and overcome the problem that traditional space modulation technology is limited by the numbe r of light sources.Therefore,this paper studies the design of 3D constellation map and its corresponding bit symbol mapping under PPAM modulation,and proposes the scheme of OSM-JPPAM in order to achieve better transmission effect.In this paper,the 3D space mapping is transformed into a mathematical problem,and the PPAM modulation symbols on each light source are optimized.The results show that,under the same system parameters,the error performance of OSM-JPPAM with 3D joint mapping is higher than t hat of other PPAM maps in the existing optical space modulation,and the proposed scheme can achieve faster transmission speed.