Realistic Modelling and Optimization of DTLS Handshakes in Constrained LPWAN Environments

With the growing popularity of Low Power Wide Area Networks (LPWANs) in large-scale Internet of Things (IoT) deployments, ensuring secure yet efficient communication presents a significant challenge. Datagram Transport Layer Security (DTLS) is designed to provide end-to-end security. However, there is a substantial communication overhead associated with DTLS that makes it impractical for resource-constrained environments, such as Low Power Wide Area Networks (LPWANs). This paper presents a simulation-based evaluation of the DTLS handshake performance over two major LPWAN technologies— LoRaWAN and mioty —incorporating realistic network conditions, including packet loss, duty cycle limitations, and message fragmentation. Unlike prior studies based on idealized airtime models, our approach provides actionable insights into real-world performance. We also utilize the Static Context Header Compression(SCHC) mechanism to reduce protocol overhead, achieving around 60% reductions in both handshake duration and message size. Furthermore, we compare the performance of DTLS handshake variants, analyzing trade-offs between certificate-based and Pre-Shared Key (PSK) authentication in constrained environments. Our research is highly relevant for the development of secure and efficient IoT communication protocols by contributing to the ongoing optimization efforts.