64 March 2015
HOW IT WORKS
In most applications, the device
to be monitored or controlled has
an integrated sensor and wireless
transceiver that connects via the
cellular system, Wi-Fi, or other
wireless link to the Internet. Cellular
links connect directly to the
Internet, while Wi-Fi or other
wireless technologies connect by
way of a gateway or router that
links to the Web.
The Internet connection
contacts a remote server that
contains the application software.
Then, the monitoring device (like a
laptop, tablet, or smartphone)
makes an Internet connection to
the server to complete the service.
Data is then captured and
displayed or stored, or some
control commands are issued.
All devices are assigned an
Internet Protocol (IP) address.
Thanks to the latest IPv6 protocol,
up to 2,128 addresses are possible.
That should be more than enough
to handle the largest collection of
Io T devices possible.
In almost every case, a wireless
link is used for communications.
Cellular connections are common
for M2M applications like vehicle
tracking, pipeline monitoring, or the
like. Wi-Fi is popular for home or
business applications since home
routers and office access points are
The fact is that any short-range
wireless technology can be used.
However, many of the most
popular standards do not provide a
convenient way to connect to the
That is now changing. Both of
the widely used Bluetooth and
ZigBee technologies now offer new
versions that are tailored to Internet
BLUETOOTH 4. 2
Bluetooth is a short-range radio
technology that operates in the
unlicensed 2. 4 GHz industrial-scientific-medical (ISM) band.
Bluetooth is a standard of the
Bluetooth Special Interest Group
(SIG). It has a range up to about 30
feet. The basic output power is 1 m W
(0 dBm), but you can use two other
power levels for longer ranges: 2. 5
m W ( 4 dBm) and 100 m W ( 20 dBm).
The 4 dBm version is the most
popular, but the higher power version
can reach out to about 100 meters
under line-of-sight conditions.
Bluetooth has a raw data rate of
1 Mb/s, but some of that is overhead
that goes to headers and error
correction so the net data rate is 723
kb/s. The modulation is Gaussian FSK
in a frequency hopping spread
spectrum (FHSS) scheme. The carrier
hops from one of the 79 channels to
another in a random sequence.
The hop rate is 1,600 hops per
second for a dwell interval of 625
microseconds. During each hop
interval, some data is transmitted. The
FHSS method makes the data very
A newer version of Bluetooth is
2.1 -- called Enhanced Data Rate
(EDR) -- and it uses π/4-DQPSK
he Internet of Things (IoT)
movement is underway and
already products are beginning
to show up. It is still early in
this trend, with billions more
devices to be built and
connected. However, now it is
easier than ever thanks to some
updated wireless standards.
First, if you are not familiar
with IoT, you should see my
June 2014 column on this
topic. In way of review, IoT is a
that is used to monitor and/or
control practically any device
by way of a communications
link including the Internet. IoT
or the Internet of Everything
(IoE) — as some call it —
(M2M) communications, as
well as machine-to-human or
human-to-machine. While the
IoT movement is just
beginning, many in industry
predict that from 20 to 100
billion devices could possibly
be connected by 2018 or 2020.
You may already own one of
these devices, such as my video
camera that I can monitor via
my smartphone from
New Short-Range Wireless
Standards Target IoT Applications
Revised Bluetooth and ZigBee versions feature
■ BY LOU FRENZEL W5LEF OPEN COMMUNICATION
THE LATEST IN NETWORKING AND WIRELESS TECHNOLOGIES