Wireless Technologies
Making the Right Choice:
Wireless Technologies for the IoT
By Anders Pettersson, Silicon Labs
Wireless connectivity is a critical part of IoT end-node
design. Important and popular connectivity options for
the IoT include Bluetooth Low Energy (LE), Bluetooth
mesh, Zigbee, Thread, Z-Wave, Wi-Fi and a wide range of proprietary
protocols in the sub-GHz band.
There are many use cases for
IoT devices, requiring a range
of connectivity capabilities. For
example, Wi-Fi is often used in
Internet protocol (IP) cameras
and devices with streaming
content. Bluetooth is ideal for
commissioning a variety of smart
home devices and other applications.
Zigbee, Thread, Z-Wave
and Bluetooth mesh support
large networks of interoperable
devices, such as smart lighting,
energy monitoring and home
security systems.
Each wireless protocol offers
its own blend of features and
characteristics, and picking the
right one depends on the end
product’s requirements. Think
about how it will be used and
how it fits in a wider ecosystem. This will guide your decision
and help you address considerations around energy efficiency,
performance, security, interoperability, upgradability and interference
with other RF sources.
Let’s look at each of these
popular connectivity options in
turn.
Bluetooth
Bluetooth is a popular and ubiquitous
protocol that has evolved
over time. Its first official specification
was released in 1999 by
the Bluetooth SIG. What started
as a protocol for mobile headsets
and streaming voice/audio
data has evolved into a powerful
and yet energy-efficient wireless
technology, with Bluetooth
Figure 1: Bluetooth mesh enables many-to-many device
communications for IoT environments such as the smart
home.
Low Energy (LE) now being most
popular for power-sensitive IoT
end-node applications.
The Bluetooth LE specification supports very-low-power
operation. To work reliably in the 2.4 GHz frequency band, it leverages
Figure 2: Dotdot provides a common application layer for the
IoT.
a robust frequency-hopping spread spectrum approach
that transmits data over 40 channels. With the enhancements
in Bluetooth v5.0, Bluetooth LE offers a tremendous amount of
flexibility for IoT designs, including multiple physical layer (PHY)
options that support data rates from 125 kbps to 2 Mbps, multiple
power levels (from 1 mW to 100 mW), and multiple security
options, up to government grade.
The launch of Bluetooth mesh
in mid-2017 added yet another
mesh networking option for the
IoT. Bluetooth mesh networking
enables many-to-many device
communications and is wellsuited
to creating IoT solutions
where tens, hundreds or even
thousands of devices must reliably
and securely communicate
with each other. Bluetooth mesh
devices are ideal for smart home,
lighting, beaconing and assettracking
applications. In retail
marketing and asset-tracking, for
example, Bluetooth mesh technology
simplifies the deployment
and management of beacons.
By combining Bluetooth LE with
mesh networking, new capabilities
and value can be introduced
into IoT devices, such as connected lights that also serve as
beacons or beacon scanners.
Zigbee
First standardized in 2004 by the Zigbee Alliance, Zigbee
operates on the IEEE 802.15.4
physical radio specification and
features lower power consumption
relative to Bluetooth and
Wi-Fi. Due to its mesh topology
and proven scalability to easily
support networks with over 250
nodes, it’s widely used in home
automation and industrial mesh
networks.
The combination of low-power
capability and ‘self-healing’
scalability makes Zigbee unique.
Adopting the 802.15.4 MAC/
PHY with short packet sizes,
the 16-channel direct-sequence
spread spectrum (DSSS) modulation
scheme, and MAC-layer
mechanisms for message-failure handling, Zigbee can operate
within low-power envelopes. Moreover, the output transmitter
power can be configured to conserve power, especially in
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