  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.
