摘要
正交频分复用OFDM(Orthogonal Frequency Division Multiplexing)与光载无线电ROF(Radio Over Fiber)技术结合为实现低成本、高速数据传输的无线网络提供了可能。但RoF链路的非线性降低了系统性能。文中在分析Mach-Zehnder调制器的静态模型基础上,提出用Volterra级数与冲击响应分析模型相结合模型化RoF非线性系统。在此模型基础上分析Mach-Zehnder调制器以及射频放大器非线性对OFDM信号的影响。仿真分析显示非线性会使OFDM信号频谱展宽,降低信号幅度,并且随着光调制指数的增加误差矢量,带外干扰增加。为OFDM-RoF系统的线性化处理以及系统光调制器调制指数的选择提供了理论依据。
The integration of orthogonal frequency division multiplexing（OFDM） and radio over fiber（RoF） technique provides the possibility for cost-effective and high data rate wireless networks. However, the nonlinear effects could severely degrade the performance of RoF and OFDM system as well. Based on analyzing the static model of Mach-Zehnder modulator, a combined Volterra series with impulse response-based analytical model is proposed to model the system. Based on this model, the different effects of nonlinear distortion on OFDM signals by Mach-Zehnder modulator and RF amplifier are analyzed. The simulation results show that the adjacent spectrum becomes wider while the amplitude of signal decreases. The analytical method is applicable for linearity analysis and for selecting the optical modulation index of OFDM ROF system.
出处
《通信技术》
2010年第1期20-22,25,共4页
Communications Technology
基金
国家自然科学基金资助项目(批准号:GZY07007)
