自由空间无线光接入系统中2种OFDM信号的应用研究  

Application Research of Two Kinds of OFDM Signals in Free Space Wireless Optical Access Systems

作　　者：周俊毅 邵宇丰[1] 王建军[1] 汪志锋[1] 李长祥[1] 周越[1] 季幸平 ZHOU Junyi;SHAO Yufeng;WANG Jianjun;WANG Zhifeng;LI Changxiang;ZHOU Yue;JI Xingping(School of Computer and Information Engineering,Shanghai Polytechnic University,Shanghai 201209,China)

机构地区：[1]上海第二工业大学计算机与信息工程学院,上海201209

出　　处：《上海第二工业大学学报》2017年第4期277-282,共6页Journal of Shanghai Polytechnic University

基　　金：国家自然科学基金(6117064);上海市教委科研创新项目(15ZZ101);上海第二工业大学校重点学科(XXKZD1605);上海第二工业大学内涵建设项目(A11NH170301);上海第二工业大学研究生项目(A01GY17F022)资助

摘　　要：自由空间光通信(Free Space Optical,FSO)是未来极具发展前景的一种宽带无线接入技术,但实际应用中必须考虑复杂天气条件对FSO通信系统收发信号的影响。通过仿真搭建了自由空间无线光接入系统,研究了采用十六进制正交振幅(Sixteen Hexadecimal Quadrature Amplitude,16QAM)以及十六进制相移键控(Sixteen Hexadecimal Phase Shift Keying,16PSK)映射生成的正交频分复用(OFDM)信号在5种天气条件(晴天、小雨、中雨、雪、雾)下传输100 m及300 m的收发特性。通过分析接收信号的光谱图、星座图和误码特性证明:晴天条件下,接收信号映射的星座点收敛特征较好,误码率低至2.5×10^(-6);雨天条件下,接收信号质量受雨衰的影响被劣化;雪或雾天气下,上述仿真系统仍能在短距离内维持通信过程;在自由空间无线光接入系统中,16QAM-OFDM信号的通信性能优于16PSK-OFDM信号。Free space optical(FSO)is a kind of broadband wireless access technology with great development prospects.However,the influence of complex weather conditions on FSO communication system should be considered in practical application.A free space wireless optical access system was built by simulation.The orthogonal frequency division multiplexing(OFDM)signals which were generated by using sixteen hexadecimal quadrature amplitude mapping(16QAM)and sixteen hexadecimal phase shift keying(16PSK)mapping transmitted with100m and300m distance under five weather conditions(sunny,light rain,moderate rain,snow,fog).By analyzing optical spectrum diagrams,constellation diagrams and bit error rate(BER)characteristics of the received signal,it was proved that under sunny weather conditions,the convergence characteristics of constellation diagram was better,and the BER was as low as2:5×10-6.On the rainy day,the system receiver performance was deteriorated by the influence of rain attenuation.Under snow or foggy weather conditions,the simulation system could still maintain short distance communication.In free space wireless optical access systems,the communication performance of16QAM-OFDM signals was better than16PSK-OFDM signals.

关 键 词：自由空间光通信 复杂天气 正交频分复用 星座图 误码率 

分 类 号：TN929.1[电子电信—通信与信息系统]