光通信系统中信道模型与FEC码型构造的分析

Analysis on Channel Model and Construction of FEC Code Type for Optical Communication Systems

对光通信系统中光发射机产生的噪声、光纤中的噪声、放大器的放大的自发辐射(ASE)噪声和光接收机噪声等噪声进行了分析与探讨。用中心极限定理将其中一些噪声综合化归成高斯噪声,再利用随机过程知识将光通信系统信道中的噪声简化为高斯噪声,从而建立了光通信系统的信道模型,即加性高斯白噪声信道模型,基于此信道模型对光通信系统中误码率进行了理论分析。并基于这些分析以及对光通信系统中前向纠错(FEC)码型的分析,提出了光通信系统中FEC码型的主要构造方法。

The existing noises, such as the noise to arising from the optical transmitter, the noise in the optical fiber, the Amplified Spontaneous Emission （ASE） noise in the optical amplifier and the noise coming from the optical receiver, in optical communication systems were analyzed and probed. Some noises in optical communication systems can be synthesized and normalized into Gauss noise by means of the central limit theorem, and then the noise in the channel for optical communication systems are reduced as the Gauss noise by means of applying the knowledge of the stochastic process, thus, the channel model（viz, additive white gaussian noise channel model） is established, based on this channel model, the Bit ErrOr Rate（BER） for optical communication systems was theoretically analyzed. This analysis shows that the decrease of the signal noise ratio in the optical channels can result in the worse BER, this problem can be improved and solved by means of applying the Forward Error Correction（FEC） technology in optical communication systems. Furthermore, based on these analyses above as well as the analysis of the FEC code type for optical communication systems, the main construction methods of the FEC code type for optical communication systems were analyzed and proposed.