IEEE Power & Energy Magazine - May/June 2015 - 73

The Center for Smart Grid Applications Research and Technology
at the IIT has installed the first networked light-emitting diode
streetlights in Chicago.

to ensure that the critical path of work was on schedule
and 2) the manufacturing of an LED fixture with integrated
communications.
While implementing the plan, the team ran into a few issues
and delays. The team facilitated many conversations between
the engineers and the facilities members and considered multiple revisions before the final installation. In addition, the network to be implemented had to be tested for signal strength
and packet resolution before the team could rely on this network for control of the streetlights. Connectivity testing was
performed in the early stages of the project to ensure that the
radios could "see" each other from every part of the campus
by using indicator lights on the radios. While this told us that
the 900-MHz signal was able to travel from the far north side
of the campus to the CSMART lab, located on the 16th floor of
the building on the far south of the campus, we still could not
verify signal strength or packet resolution.
Using Silver Spring Networks' configuration software and communication test unit, the CSMART project
team confirmed that the radios could communicate via the
neighborhood area network from the proposed streetlight
locations, although the received signal strength indication
(RSSI) from the far end was on the fringe of our defined
range, as shown in Figure 9. Overall, this would not prove to
be a major obstacle due to the mesh network that is formed

when multiple Silver Spring Networks radios are implemented. The closest radio to the lab can always provide a
last hop before reaching the AP, which is located in the lab,
as long as all the other radios are able to communicate with
this one.
The project team was able to coordinate the successful
installation of the streetlight pilot before the required completion date and demo them during the 2014 Great Lakes
Symposium at IIT. The final steps would be to integrate this
system into the existing SCADA and to do extensive testing
related to energy, economics, and resilience, the results of
which we will discuss later.

Benefits of Networked LED Streetlights
Streetlights have two characteristics that make them ideal
candidates for inclusion in a smart city deployment. First,
they are ubiquitous: every road and highway is lighted by
lamps for nighttime usage as well as for safety. Second,
they are very favorably positioned: streetlights are typically
mounted atop tall, regularly spaced poles with an unimpeded
line of sight between fixtures. This means that networking
streetlights generally does not necessitate the deployment of
any additional networking equipment, and in fact the streetlights can be expected to improve the operational resilience
and reliability of the network itself.

figure 10. In this photo, old high-pressure sodium fixtures are on the left, and new LED fixtures are on the right. [Source:
Patrick Burgess (IIT), used with permission.]
may/june 2015

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