由于自由空间光通信(FSO)具有速率高、功耗低、机动性强等特点,利用自由空间光信道传输射频信号(Radio Over FSO),将其与正交幅度调制(QAM)相结合,可以使二者互相补充,发挥各自的优势。本文论述了自由空间光通信中正交幅度调制(QAM)的原理和特性,并进行了QAM调制和解调的matlab仿真。通过对得到的仿真结果进行比较和分析,研究了QAM信号的解调性能,分析计算了QAM信号相干解调的误比特率(BER)、误码率(SER)和信道容量。为Radio Over FSO系统的实现奠定了理论基础。
FSO has features of high rate,low power consumption and good maneuverability.Radio Over FSO connected with QAM can exploit the particular advantages of each.This paper discusses the theory and feature of QAM in the FSO communication and make the Matlab simulation of QAM modulation and demodulation.Though comparing the simulation result,it analyses the decoding performance of QAM signal and computes the BER,SER and channel capacity of the QAM signal under the condition of the coherent demodulation.It brings the theoretical foundations to Radio Over FSO.