全双工光载无线通信链路模型研究

A scheme of full-duplex radio over fiber link model

提出了一个新的全双工光载无线通信链路模型。方案的下行链路采用两个马赫曾德尔调制器级联以产生六倍频毫米波;采用单边带调制,有效防止了码元走离现象,提高了传输距离;上行链路复用了下行链路中的一阶光边带以作为上行基带信号的载波,从而无需在基站中额外配置激光源;采用延时零拍法解调,减少了对毫米波本地振荡器的需求,降低了系统的成本。仿真结果表明,所提出的全双工模型中,仅用10 GHz频率的调制信号就能产生60 GHz的毫米波,大大降低了调制信号频率,且下行链路传输距离可达250 km,而上行链路传输距离大于300 km。

A new full-duplex radio over fiber link model was proposed in this paper. For the down link, two mach-zehnders modulator cascaded were employed to generate sextupling-frequency millimeter wave;the single side-band modulation was used to overcome the walk-off effect, thereby the transmission distance was effectively improved. In the meanwhile, the first order sideband was employed as the carrier of uplink baseband signal and thus the requirement of additional laser source was eliminated. Furthermore, self-homodyning demodulation method was adopted to avoid the need of local oscillator, thereby the cost of system was reduced. Numerical result shows that the proposed full-deplex model can produce 60 GHz millimeter wave by only using 10 GHz modulated signal. The transmission distance for down link can reach 250 km and that for the up link is more than 300 km.