Latency Evaluation in Ad-hoc IoT-Blockchain Network <Abstract> Many researchers are studying the applications that ensemble blockchain and IoT. In such applications, a blockchain is normally deployed on top of the infrastructure-based underlying IoT network (e.g., Wi-Fi), which incurs the single point of failure issue. This work considers using infrastructure-less IoT for blockchain (i.e., ad-hoc IoT-blockchain network) to avoid the issue. Like in other networks, latency is one of the essential parameters to assess the network quality in the ad-hoc IoT-blockchain system. The latency is inherently related to the synchronization of transactions and blocks messages in the blockchain. Therefore, latency evaluation in an ad-hoc IoT-blockchain network is necessary. This research evaluates two latency metrics named Transaction-Oriented Latency (TOL) and Block-Oriented Latency (BOL) in an ad-hoc IoT-Blockchain system with Ethereum and two well-known consensus mechanisms: Proof of Work (PoW) and Proof of Authority (PoA). We create a smart contract that the different number of transactions can trigger; we then adopt the measurement method of the latency values. The evaluation results reveal the TOL and BOL following the transaction number in both the ad-hoc IoT-blockchain with PoA and PoW. |