Performance evaluation and adaptive optimization of COP-1: A case with security enhancement

Secure communications in the context of civil space missions gained a major attention in the last few years, several research groups and international organizations are currently developing the required security mechanisms, based on widely used protocols of the Consultative Committee for Space Data Systems (CCSDS) Packet TM and TC family. However, given the hostile space communication environment, when security mechanisms are integrated within existing space communication systems, they greatly affect the transmission performance. This paper presents an evaluation of throughput efficiency for COP-1 protocol when security mechanisms are integrated, in the context of space communications. Based on such evaluation, the authors propose an adaptive algorithm which allows COP-1 directives to dynamically optimize the sliding window size and frame length, according to estimates of the channel fading characteristic. The proposed algorithm is particularly useful for deep space channels, over which the channel tends to be fading kind.