Deep-space file transmission method based on dual-retransmission strategy

Abstract

The invention provides a deep-space file transmission method based on a dual-retransmission strategy, which comprises a primary transmission stage and a retransmission stage. On the basis of a coherent file distribution protocol (CFDP) delay negative acknowledge (NAK) mode, the double-retransmission strategy is only used for error or missed protocol data units (PDUs) at the retransmission stage, i.e. if an error probability of a single PDU is P, the probability that two identical PDUs simultaneously have errors or are simultaneously missed is P<2>, and the retransmission times are reduced by reducing the error probability of the PDU, so that a total file transmission time is shortened, and the reliability and the validity in communication can be guaranteed. The deep space file transmission method is very suitable for the fields with long distance, high packet loss ratio and short connection time.

Description

technical field [0001] The invention relates to a deep space file transmission method, in particular to a deep space file transmission method based on a double transmission strategy. Background technique [0002] Deep space communication is very different from ground communication, and the main challenges it faces are: 1. Long delay; 2. Intermittent link; 3. High and variable bit error rate; 4. Link asymmetry; There are several communication protocols as follows, but each has its own disadvantages. [0003] 1. TCP protocol has poor performance in deep space communication [0004] The above-mentioned challenges faced by deep space communication make the traditional TCP protocol directly applied to the deep space communication system will cause many problems. First of all, the propagation delay in deep space communication is huge. For example, the round-trip delay from Mars to Earth is usually between 8.5 and 40 minutes depending on the orbital position of the star. If the r...

AI Technical Summary

Problems solved by technology

In the deep space network with a large link delay or delay-bandwidth product, various improved TCP protocols have little difference and poor performance. The TCP protocol cannot even communicate between the Earth and Mars.

[0005] 2. The UDP protocol is unreliable

However, in terms of the retransmission mechanism, it is only required to retransmit the erroneous or lost PDU once, which will lead to poor performance in an environment where the transmission distance is very long and the link bit error rate is extremely high.

Images