Contact graph routing algorithm based on stochastic linear network coding in deep space communication

Abstract

The invention discloses a contact graph routing algorithm based on random linear network coding in deep space communication. The contact graph routing algorithm comprises the following steps: a sourcenode processes a data packet to be sent by adopting random linear network coding; the source node selects a plurality of link disjoint paths according to the predicted contact graph and transmits theencoded packets on the plurality of paths. the received data packet is directly forwarded at the intermediate node and re-encoded before forwarding; the destination node receives the data packets anddecodes them, and feeds back the packets which cannot be decoded successfully to the last hop node set, the last hop node set sends the encoded packets which are helpful to the destination node decoding, so that the destination node can decode the packets quickly and reduce the transmission delay. The invention adopts random linear network coding to send the original data, and controls the redundant data packets in the network through the link state to ensure that the destination node can be decoded while reducing the waste of network resources and reducing the decoding waiting time delay ofthe node.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a contact graph routing algorithm based on random linear network coding in deep space communication. Background technique [0002] In the "Radio Regulations" formulated by the World Radio Management Conference, the distance from the earth 2×10 6 The space within km is called near space, and the space beyond this distance is called deep space. my country's aerospace industry directly defines the vast space from the earth to the moon as deep space. Deep space communication covers all communication between probes and planets in space. Compared with ground communication, the characteristics of deep space communication mainly include: [0003] (1) The distance between nodes is long, and the propagation delay is huge and time-varying. The periodic movement of the satellite makes the propagation delay between nodes change, and the link is interrupted intermittently. Except for...

AI Technical Summary

Problems solved by technology

Except for the moon, the one-way propagation delay from the earth to other celestial bodies ranges from 2.2 minutes to 7 hours. Reliable transmission poses great challenges

[0004] (2) The link is interrupted intermittently

[0005] (3) The transmission rates of forward and reverse links in deep space are seriously asymmetric

This asymmetric link makes reliable interaction between nodes very difficult, and it is difficult to obtain information about network topology changes in real time.

[0006] (4) Node resources are limited

Nodes in deep space are sparse, and communication opportunities are few. Satellite nodes are affected by factors such as weight, size, power supply facilities, and cost. The number, storage space, and processing capacity of nodes are severely limited.

[0007] (5) The path loss is serious, the signal-to-noise ratio at the receiving end is extremely low, and the bit error rate is high

[0008] To sum up, the deep space communication environment is extremely harsh, which is not conducive to the reliable transmission of data

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