The self-adaptive bidirectional ARQ transmission window regulation method based on CCSDS proximity-1 for MARS exploration

Mars is the next milestone in our exploration of solar system. As the result of the very long distance between earth and Mars, it takes a long time for the microwave signal to travel between them. Therefore, the ground station cannot control the deep space probe on and around the Martian surface in real time, which puts forward higher requirements for fully autonomous and high reliable communication between deep space detectors. The forward link is usually defined as the link from the orbiter to the rover, which includes the telecommand from the earth station. The return link is usually defined as the link from the rover to the orbiter, which contains the key telemetry of the rover and the information which are collected by the payload of the rover. Due to the limited time of visible communication arc, the forward link telecommand and the return link information are both very important, frame loss is not allowed in them. Thus, the ARQ (Automatic Repeat-reQuest) mechanism is introduced in CCSDS proximity-1 protocol to ensure the reliability of the data transmission. However, the efficiency of ARQ will be greatly affected when the forward and return rates do not match, which will cause a sharp decrease of the communication throughput in the arc section. In this paper, the self-adaptive bidirectional ARQ transmission window regulation method based on CCSDS proximity-1 for Mars exploration is presented, which could adaptively estimate the time delay and change the window parameter to ensure the high efficiency of both links. Compared with the traditional method, higher throughput could be achieved during the precious visible arc. The hardware implementation shows that only limited logic resource are needed which is suitable for the Mars exploration mission.