1. Introduction
Scalability is the main concern for public blockchain-based Internet of Things (IoT) applications. As the number of IoT devices increases each year, coupled with the emergence of the 5G network, this trend is expected to accelerate, driven by the release of a new generation of IoT devices. Existing public blockchains try to solve scalability issues by using different approaches such as on-chain (e.g., sharding) and off-chain (e.g., using sidechain, layer-2 scaling) methods, or by completely using different data structures (e.g., Direct Acyclic Graph used in IOTA), as discussed in [1]. Ethereum 2.0, currently known as the Consensus Layer, is expected to offer a throughput of up to 100,000 transactions per second (TPS) when sharding is implemented. One of its existing technologies—rollups—is already used to improve scalability through layer-2 protocols [2]. This is…
