Cellular LTE and Solar Energy Harvesting for Long-Term, Reliable Urban Sensor Networks: Challenges and Opportunities

TL;DR

This study evaluates a year-long LTE-connected, solar-powered urban sensor network in Chicago, highlighting its potential and challenges, especially in socioeconomically disadvantaged neighborhoods, to inform future smart city deployments.

Contribution

It provides the first extensive real-world analysis of LTE and solar-powered urban sensor networks, identifying key performance issues and social disparities.

Findings

11 sites with inadequate LTE signal strength

33,000 hours of data loss due to solar energy issues

Disadvantaged neighborhoods face more connectivity and power challenges

Abstract

In a world driven by data, cities are increasingly interested in deploying networks of smart city devices for urban and environmental monitoring. To be successful, these networks must be reliable, scalable, real-time, low-cost, and easy to install and maintain -- criteria that are all significantly affected by the design choices around connectivity and power. LTE networks and solar energy can seemingly both satisfy the necessary criteria and are often used in real-world sensor network deployments. However, there have not been extensive real-world studies to examine how well such networks perform and the challenges they encounter in urban settings over long periods. In this work, we analyze the performance of a stationary 118-node LTE-connected, solar-powered sensor network over one year in Chicago. Results show the promise of LTE networks and solar panels for city-wide IoT deployments, but also reveal areas for improvement. Notably, we find 11 sites with inadequate RSS to support sensing nodes and over 33,000 hours of data loss due to solar energy availability issues between October and March. Furthermore, we discover that the neighborhoods most affected by connectivity and charging issues are socioeconomically disadvantaged areas with a majority Black and Latine residents. This work presents observations from a networking and powering perspective of the urban sensor network to help drive reliable, scalable future smart city deployments. The work also analyzes the impact of land use, adaptive energy harvesting management strategies, and shortcomings of open data, to support the need for increased real-world deployments that ensure the design of equitable smart city networks.