COLLABORATIVE BLOCKCHAIN FOR SPACE-AIR-GROUND INTEGRATED NETWORKS

A space-air-ground integrated network (SAGIN) provides comprehensive interconnection and quality of service. Such an integrated network poses security concerns by bringing together a variety of devices from different untrusted authorities. Blockchain, as a decentralized ledger, although showing great potential to solve the security issues in SAGIN, may bring up intolerable latency by sequentially validating requests and take up numerous storage resources by keeping a complete replica of the entire chain in every node in a large-scale network. It becomes a feasible solution to use multiple parallel blockchains to efficiently manage different segments of SAGIN and blockchain collaboration technology to enable necessary inter-segment cooperation. Toward this end, we propose a collaborative blockchain architecture for SAGIN to achieve secure and efficient management of diverse resources. Each segment of SAGIN (i.e., space, air, and ground network) maintains a specially designed block-chain while blockchain collaboration is enabled. We then design an incentive-based collaborative blockchain for space-air-ground mobility management to encourage the participation of different network segments and ensure the security of collaboration using relay chain technology. Numerical results show the effectiveness of the proposed framework.