CDMA在FTTR中应用的载噪比分析

讨论了基于光纤无线网络总线链接方式的无线信号接入。在光纤到铁路沿线（ＦＴＴＲ）方案中对终端站接收的无线信号进行扩频编码，进入光纤通道并到达中心站。文中针对上行通道的ＣＮＲ给出了计算方法。结果表明，由于ＣＤＭＡ的扩频作用减少了光信号噪声，使得ＦＴＴＲ方案中按照需要增加终端站和信道数目成为可能。

CNR Analysis of CDMA used in Fiber to the Railway

This article discussesa radio signal access based on the fiber radio bus link.In the solution of FTTR,thereceived radio signals was multiplied by a pseudorandom noise (PN) at TerminalStations(TSs) ,and encapsul ated into the envelope of optical signal by IM of LD.Acalcuation method of the upstream CNR was given.The result shows that it is possible toincrease the TSs and channels as per requirements in FTTR solution,because the opticalsignal bea t noise is reduced by spectrum spreading of CDMA.