B. Link Layer Technologies
An urban IoT system, due to its inherently large deployment
area, requires a set of link layer technologies that can easily cover
a wide geographical area and, at the same time, support a possibly
large amount of traffic resulting from the aggregation of an
extremely high number of smaller data flows. For these reasons,
link layer technologies enabling the realization of an urban IoT
system are classified into unconstrained and constrained technologies.
The first group includes all the traditional LAN, MAN,
and WAN communication technologies, such as Ethernet, WiFi,
fiber optic, broadband Power Line Communication (PLC), and
cellular technologies such as UMTS and LTE. They are generally
characterized by high reliability, low latency, and high transfer
rates (order of Mbit/s or higher), and due to their inherent
complexity and energy consumption are generally not suitable
for peripheral IoT nodes