In this paper, a two lines based power line carrier frequency communication network system is schemed out. In this way, the electric power and communication signals are transmitted through the same two wires. All observation equipment can be connected by these two wires, the power supply and communication signals can be transmitted through them, no other wires are needed. This paper discusses the way to provide energy and communicate via the same power line, and to break the distance limit of the carrier frequency communication (about 10km). A token-ring network frame can solve all of these problems. The topological structure and communication protocol are discussed in detail, and a general model of the deep ocean monitoring network system based on Field Bus is established.
Currently, with the growth of exploration of resources in general and exploitation of marine resources in particular, information transmission and energy supply in the deep sea becomes one of the most critical problems that we must solve. Environment and condition of the communication underwater differs from the communication on land greatly, so many communication techniques which are used widely on land cannot be used underwater. There are two ways to communicate in sea water currently: wired communication and wireless communication. The wired type primarily uses optical fiber and special cable; the wireless type primarily uses acoustic communication. The optical fiber communication has the advantages of great transmission capacity, long-distance transmission without relay and few mistake codes (Wen, Q., Ritcey, j. A. 1994). Underwater acoustic communications is a wireless communication method, and it can be used flexibly (Song, B. G., Ritcey, J. A., 1995; Stojanovic, M., Catipovic, J., 1993), but there are also some difficulties on the application of underwater acoustic communication technique for the deep-sea information transmission.
