【Author】
Zhang, Zhen; Guo, Bing; Zhu, Lidong; Shen, Yan; Qin, Chaoxia; Li, Chengjie
【Source】CHINA COMMUNICATIONS
【Abstract】In LEO (Low Earth Orbit) satellite communication systems, the satellite network is made up of a large number of satellites, the dynamically changing network environment affects the results of distributed computing. In order to improve the fault tolerance rate, a novel public blockchain consensus mechanism that applies a distributed computing architecture in a public network is proposed. Redundant calculation of blockchain ensures the credibility of the results; and the transactions with calculation results of a task are stored distributed in sequence in Directed Acyclic Graphs (DAG). The transactions issued by nodes are connected to form a net. The net can quickly provide node reputation evaluation that does not rely on third parties. Simulations show that our proposed blockchain has the following advantages: 1. The task processing speed of the blockchain can be close to that of the fastest node in the entire blockchain; 2. When the tasks' arrival time intervals and demanded working nodes(WNs) meet certain conditions, the network can tolerate more than 50% of malicious devices; 3. No matter the number of nodes in the blockchain is increased or reduced, the network can keep robustness by adjusting the task's arrival time interval and demanded WNs.
【Keywords】distributed computing; public blockchain network; consensus mechanism; credibility; fault-tolerance
【标题】用于低地轨道卫星通信中容错分布式计算的公共区块链共识机制
【摘要】在LEO（低地球轨道）卫星通信系统中，卫星网络是由大量的卫星组成的，动态变化的网络环境影响着分布式计算的结果。为了提高容错率，提出了一种新颖的公共区块链共识机制，在公共网络中应用分布式计算架构。区块链的冗余计算保证了结果的可信度；而带有任务计算结果的交易依次分布在有向无环图（DAG）中存储。节点发出的交易被连接起来，形成一个网。该网可以快速提供不依赖第三方的节点信誉评价。仿真结果表明，我们提出的区块链具有以下优势。1. 区块链的任务处理速度可以接近整个区块链中最快的节点；2.当任务的到达时间间隔和需求的工作节点（WNs）满足一定条件时，网络可以容忍50%以上的恶意设备；3.无论区块链中的节点数量增加或减少，网络都可以通过调整任务的到达时间间隔和需求的WNs保持稳健性。
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