Research And Simulation Of WDM/TTE Unified Airborne Network

With the performance enhancement and the increasing amount of information of the avionic devices, the traditional airborne network based on coaxial cable and twisted pairs as transmission media cannot meet the requirements of the future avionics system. Due to its enormous bandwidth, small volume, light weight, good expansibility, fault-tolerant capability and fast reconstruction ability, the WDM optical airborne network is considered as a preferred choice for the future backbone network. The current airborne network includes all kinds of data buses and a variety of hybrid network architectures, and whose cabling system is overlapping. When a new equipment accesses, we need to alter the network’s overall structure. In contrast, WDM airborne network can reduce multifarious links, and the edge nodes intercommunicate through accessing the backbone. When adding some nodes, we just need to access them to the backbone through the uniform interfaces without altering the network structure. The transport services in avionics environment is real-time, explicit and predictable. The Time Triggered Ethernet(TTE) is well applicative for such services accesses to the WDM optical airborne network.In this thesis, we summarize the research status and development background of the airborne network, WDM technology and TTE technology firstly. After describing the fundamental principles of WDM and TTE, a unified airborne network based on WDM and a TTE network architecture are proposed. Backbone network is a communication hub connecting the entire network, and also a key part of the airborne network. The edge networks communicate with each other through the airborne backbone. Here we provide a WDM backbone of mesh topology with four nodes. Each node configures the wavelength paths between all the access networks using static wavelength routing in advance, thus realizing all-optical wavelength communication between any node and any nonnative access networks. Time-triggered Ethernet is adopted to build access networks, each of which contains several TTE and an optical access node. The TTE network adopts star topology. Every time-triggered node has its predefined time scheduling table, and sends, receives or forwards the time-triggered messages, rate constrained messages and the traditional Ethernet messages in accordance with the table. The optical access node converts the local electrical signals into wavelength signals to transmit in the backbone, and vice versa on the reverse direction.To verify the scheme proposed above, a simulation model about unified airborne network in OPNET is implemented, which consists of WDM backbone nodes, optical access nodes, TTE terminals and a TTE switches. Link models of the access network and the backbone, and three kinds of frame formats are also defined. On this basis a simulation model of network is tested. Through simulation data analysis, we find that TTE network is compatible with traditional Ethernet and AFDX network, and that it can meet the requirements of real-time and accuracy for avionics system.