Mitigating Messaging and Processing Load in IoT Environments Managed by Blockchain

We study the use of Blockchain in an Internet of Things (IoT) environment where microservices are provided by sensors. Blockchain assures secure and trustworthy transactions, yet it causes high load caused by block creation on the numerous IoT nodes. To mitigate the load, sensor nodes are clustered and block creation is restricted to IoT cluster managers in the distributed Blockchain ledger. The concept is exemplified by a use case describing a neighborhood of smart homes that are equipped with environmental sensors such as dust, temperature, and precipitation sensors. We provide an implementation of the Blockchain IoT system comprising two consensus algorithms, Proof of Work (PoW) and Proof of Stake (PoS). By means of simulations conducted in Mininet, we derive first results which reveal that -- depending on the sensor polling period -- the service response time can be reduced by clustering. Further, clustering reduces PoW conflicts to about 30% due to creating fewer blocks.