Research On The Protocol Of Frame With Variable Length In Space Communication And Transmission Technology With Variable Information Rate

In order to make the increasingly complex space task can be carried out in a standardized way to exchange and process data, the National Aeronautics and Space Administration, the European Space Agency and many other countries's Space Agency setted up the Consultative Committee for Space Data System in the 1982. Its duty is to develop a standardized communication structure, communication protocol and operation.The paper introduced the structure, the model of Principal Network, the type of operation and the characteristics of technology in the CCSDS protocol. On the study of the multiplexing of packets channel actualized in the VCLC layer and the multiplexing of virtual channel actualized in the VCA layer, the paper anslyzed the circs of framing , the efficiency of multiplexing of packets channel and three modes of the multiplexing of virtual channel.Then the paper established a model of system throughput. The paper put forward a program of communication using frame with variable length. And the length of the frame is variable based on the source of data and the BER in the space link. The relevant model of communication system had been established. The programs were compared in the point of probability of correct frame synchronization and system throughput. The simulation result showed that the proposed method can provide higher throughput than the one using frame with fixed length, without reducing the probability of correct frame synchronization in the lower BER.Finally, a program of variable information data rate using different numbers of check-bits in the frame structure had been propounded. And then a compare of the coding time and the system throughput had been made.