[Paper Review] Trusted Wireless Monitoring based on Blockchain over NB-IoT Connectivity

Lam Duc Nguyen, Anders E. Kalør+2 more|arXiv (Cornell University)|Apr 14, 2020

IoT and Edge/Fog Computing14 references29 citations

TL;DR

This paper proposes a blockchain-integrated NB-IoT framework for trusted environmental monitoring, enabling immutable, transparent data logging of air pollution and emissions. By leveraging Hyperledger Fabric on NB-IoT devices, it achieves data integrity and trust without burdening devices as full nodes, though it increases downlink traffic and end-to-end latency by up to 1.63 seconds with large blocks.

ABSTRACT

The data collected from Internet of Things (IoT) devices on various emissions or pollution, can have a significant economic value for the stakeholders. This makes it prone to abuse or tampering and brings forward the need to integrate IoT with a Distributed Ledger Technology (DLT) to collect, store, and protect the IoT data. However, DLT brings an additional overhead to the frugal IoT connectivity and symmetrizes the IoT traffic, thus changing the usual assumption that IoT is uplink-oriented. We have implemented a platform that integrates DLTs with a monitoring system based on narrowband IoT (NB-IoT). We evaluate the performance and discuss the tradeoffs in two use cases: data authorization and real-time monitoring.

Motivation & Objective

• To address data integrity and trust issues in IoT-based environmental monitoring systems where emissions data has high economic value and is prone to manipulation.
• To evaluate the integration of distributed ledger technology (DLT) with narrowband IoT (NB-IoT) for real-time pollution monitoring and data authorization.
• To analyze the tradeoffs in traffic balance, communication overhead, and end-to-end latency when using blockchain in NB-IoT networks.
• To assess the feasibility of using lightweight DLTs like Hyperledger Fabric in energy-constrained, uplink-oriented NB-IoT environments.
• To demonstrate that blockchain can be effectively used in environmental monitoring without making IoT devices act as full nodes, preserving energy efficiency.

Proposed method

• The system uses NB-IoT devices to generate and transmit sensor data (e.g., CO2, NOx) as blockchain transactions to a centralized DLT network.
• Transactions are processed via a smart contract in Hyperledger Fabric that computes average CO2 levels and triggers ledger updates when thresholds are exceeded.
• The framework employs endorsing peers (E) to validate transactions before consensus, with payload sizes ranging from 50 B to 200 B for uplink and 31 B for downlink.
• Block size (b) is varied from 10 to 100 transactions per block to evaluate its impact on end-to-end latency and traffic load.
• The system is evaluated in two use cases: data authorization and real-time CO2 monitoring, with performance measured in traffic ratio, latency, and overhead.
• Communication overhead and latency are measured across different configurations of endorsing peers and block sizes to assess scalability and efficiency.

Experimental results

Research questions

• RQ1 How does integrating blockchain into NB-IoT affect the uplink-to-downlink traffic ratio and overall communication overhead?
• RQ2 What is the end-to-end latency of transaction confirmation in a blockchain-enabled NB-IoT monitoring system, and how does it vary with block size?
• RQ3 How does increasing the number of endorsing peers affect the downlink traffic load and system security?
• RQ4 To what extent does blockchain integration compromise the energy efficiency of NB-IoT devices in monitoring applications?
• RQ5 Can a lightweight DLT like Hyperledger Fabric be effectively used in NB-IoT networks without requiring devices to act as full blockchain nodes?

Key findings

• The average uplink-to-downlink traffic ratio increases significantly with blockchain integration, reaching nearly 2:1 when the number of endorsing peers (E) is 2 and uplink payload is 50 B.
• End-to-end latency increases from 0.832 seconds in conventional NB-IoT to 1.63 seconds in DLT-based NB-IoT when using a block size of 100 transactions per block.
• The increase in downlink traffic is substantially higher than the increase in uplink traffic, especially as the number of endorsing peers increases, indicating a major shift in traffic symmetry.
• Despite increased latency and downlink load, the performance overhead remains relatively low, with end-to-end latency remaining under 2 seconds for typical monitoring intervals.
• Smaller block sizes (e.g., b = 10) result in lower end-to-end latency, comparable to conventional NB-IoT, making them suitable for time-sensitive monitoring applications.
• The system achieves strong data integrity and trust through distributed consensus and cryptographic hashing, without requiring IoT devices to store or validate the full ledger.