Quality of Service Enhancement and Security Assurance in Internet of Things Networks: A Survey and Integrated Blockchain Sidechain Architecture

The Internet of Things (IoT) enables various applications, including healthcare and smart grids, many of which demand a high-quality of service (QoS) and are subject to external and internal attacks. While blockchain-based approaches provide built-in security, they generally incur a significant computation burden, negatively affecting QoS. This paper adopts a hybrid approach that integrates a comprehensive survey with the introduction of a novel blockchain sidechain architecture. The paper begins with an extensive review of QoS in IoT networks, sidechain mechanisms for improving QoS, blockchain for IoT security, and the deployment of blockchain in IoT via sidechains. This study then proposes a novel architecture for a blockchain sidechain that features a dynamic-truncation sidechain management model to combat the QoS and security tradeoff problem. The proposed architecture enhances network QoS through the sidechain while providing essential security via a blockchain mechanism. The study utilizes the Tendermint consensus mechanism, which is specifically designed to mitigate threats such as Sybil, denial-of-service (DoS), and double-spending attacks. Experimental evaluations demonstrate that the proposed architecture yields significant QoS improvements compared to non-sidechain methods, including a 22.54% reduction in communication delay, a 28.11% decrease in energy consumption, and a 35.64% increase in network throughput. The model also achieves a 10.47% improvement in packet delivery ratio and a 22.37% reduction in delay jitter, while consuming only 2.11 KB of storage, representing a 30.37% reduction in storage usage. Additionally, the suitability of the proposed approach for resource-constrained IoT environments is demonstrated by both its ability to deliver faster block generation than state-of-the-art methods and by the robustness of the Tendermint consensus mechanism, which is confirmed through security analysis. Coupled with the comprehensive review and insights into future research directions, this work serves as both a foundational reference and a pathway for advancing QoS and security in IoT networks.