室内无线光通信正交空时编码及调制技术

摘要

在无线光通信中,调制和编码及其设计方案是实现直射信道与漫射信道容量优化的关键技术.采用4-脉冲位置调制和正交空时编码技术是最佳方案.因为这种调制和编码技术优于L-脉冲位置调制方案,可以传输更多信息.4-脉冲位置调制正交空时编码是一个基于MIMO的2×2方案,即有两个发射器和两个接收器,构成一个双信道通信系统.其工作原理是:当直射信道处于工作状态时,漫射信道处于等待状态.当直射信道被障碍物阻断时,立即转到漫射信道.二者的工作状态可以自由切换.当然,如果需要,两者都可以处于工作状态.这使得无线光通信能逾越障碍,实现不间断通信.%In wireless optical communication,modulation and coding and its design scheme are the key technologies to realize the optimization of direct incident channel and diffuse channel and capacity.Using 4-PPM and orthogonal space-time coding technology is the best scheme.Because this modulation and coding technology can transmit more information than L-PPM.4-pulse position modulation and orthogo-nal space -time coding are a 2×2 scheme based on MIMO.That is,there are two transmitters and two receivers,which constitute a dual-channel communication system.The working principle is that when the direct channel is in a working state,the diffusing channel is in a waiting state.When the direct incident channel is blocked by an obstruction,immediately transfer to the diffuse channel.The working state of the two can be freely switched.Of course,both can be in a working state if needed.This enables wireless opti-cal communication to overcome obstacles to achieve uninterrupted communication.