CRP: A Cluster-Based Routing Protocol for Lightweight Nodes in Payment Channel Networks

Although blockchain empowers the IoT trading market and presents new development opportunities for IoT, scalability issues of blockchain limit its application in this area. Payment Channel Networks (PCNs) have emerged as a promising solution to address the scalability issues. With the help of routing protocols, two users can utilize payment channels to conduct off-chain transactions. However, most Payment Channel Network (PCN) routing protocols overlook the scalability of PCNs, resulting in substantial storage, communication, and computational overhead for lightweight nodes, such as IoT devices. Additionally, frequent utilization of a payment channel can quickly exhaust the channel’s balance, leading to congestion and causing subsequent payments to fail. Channel congestion restricts the throughput of PCNs, yet most PCN routing protocols lack designs for channel congestion control. In this paper, we propose a Cluster-based scalable and high-throughput Routing Protocol (CRP), to enhance the scalability and throughput of PCNs. CRP organizes PCNs into clusters to reduce the average routing table size, thereby alleviating users’ storage, communication, and computational overhead. Furthermore, CRP aims to minimize maximum channel congestion when selecting payment routes, thereby improving throughput. Extensive simulations demonstrate that CRP achieves high scalability and throughput compared to state-of-the-art PCN routing protocols.