Research On SUPER FEC In Optical Communication System

At present, Forward Error Correction(FEC) technologies are widely applied in optical communication systems in order that the error can be found and corrected by adding a small quantity of the redundant information to the signal, as a result, the tolerance of the Optical Signal Noise Ratio(OSNR) for the receiving end is reduced to improve the Bit Error Rate(BER) performance of optical communication systems, enhance the reliability of optical communication systems, extend the transmissiondistance of optical signals, decrease the transmitting power of the optical transmitter and reduce the cost of optical communication systems.The ITU-T has developed the researches of the FEC codes for the rapid development of optical communication systems for recent years, and the relative recommendations such as ITU-T G.707, G.975, G.709, G.975.1 and so forth have been proposed one by one. However, with the increasing development of optical communication systems toward longer distance, larger capacity and higher bit rate, the further improvements of the transmission rate and distance are heavily limited due to the accumulated optical effects in transmission optical fibers. As a result, it has been becoming necessary to develop the novel more powerful Super Forward Error Correction(SFEC) code type in order to gain the higher Net Coding Gain(NCG) and the better error-correction performance to meet the requirements of the rapid development for optical communication systems, compensate for serious transmission quality degradation and avoid using the dispersion-compensating technologies to need the expensive and complex devices and so forth. Seeing that this developing trend of optical communication systems, it is very necessary to deeply research the novel scheme of the SFEC code type, theoretically analyze and practically verify its application in optical communication systems so as to better and better apply it in optical communication systems to improve the communication quality of optical communication systems and decrease the cost of optical communication systems.Firstly, concatenated code and interleaver have been researched this dissertation, the main contents are the encoding and decoding structure of concatenated code, the design of interleavers in common use and the rules for designing interleavers in the concatenated code system. Secondly, this dissertation has completed detailed analysis and study on the SFEC schemes in ITU-T G.975.1 proposal, besides, the simulations of three SFEC schemes have been achieved. Finally, the new SFEC schemes based on concatenated code have been designed.