The Data Processing Of Optical Supervisory Channel In DWDM System

Demands for transmission network bandwidth and switching system capacity are growing at an unprecedented rate with the rapid growth in IP services. In order to make better use of optical fiber resource and to increase the transmission system capacity, DWDM (Dense Wavelength Division Multiplexing) technology has been proposed and widely used, it has become one worldwide key technical means to expand the transmission capacity of the existing optical fiber communication system in recent years.OSC (Optical Supervisory Channel) is a relative independent subsystem of DWDM system, which is responsible for transmitting network management, service and monitoring information of DWDM system. According to the standard of DWDM, the physical interface of OSC should meet the standard ITU-G.703 requirements, its frame structure and bit rate should also meet the standard ITU-G.704 requirements. Practically, in order to meet the need of security, the work of scrambling/descrambling should be done before and after CMI encoding/decoding.Based on the research and development of OSC intelligent adapting equipment, have studied the implementation of OSC data processing. The research has been applied in practical system reliably, which worked stably and showed a good performance. The main contents and innovative points include:1. Principles of DWDM and OSC were researched, as well as DWDM system architecture and the technology of OSC data processing.2. OSC data processing board was developed. According to the function requirement of OSC data processing in OSC intelligent adapter equipment, OSC data processing board was designed. It can support many functions, such as light/electricity transformation, CMI (Coded Mark Inversion) encoding/decoding, scrambling/descrambling, El framing/deframing, HDB3 encoding/decoding, scrambling/descrambling configuration interface and serial communication interface. OSC data processing board can support two implementation schemes of OSC intelligent adapter, which is an innovative point of this paper.3. OSC data processing modules were designed and realized, such as CMI encoding/decoding, scrambling/descrambling, El framing/deframing, scrambling/descrambling configuration and system fault-tolerant. Experiments showed that the OSC data processing unit met the anticipated demands. The selections of scrambling/descrambling algorithm which was realized in the way of human-machine interaction by scrambling/descrambling configuration module and the system fault-tolerant which was realized by system fault-tolerant module are two others innovative points of this paper.