will begin a testing and certification
program like Wi-Fi and ZigBee.
How is this used? The plan is to use
it to transmit video over short distances
such as to wall-mounted TV screens and
between TV sets and DVD players and
other video gear. Video requires very
high speeds and UWB can do it. Another
application is a wireless USB port
for PCs and laptops. The USB serial
interface is the most widely used today
with data rates to 480 Mbps. A wireless
version will replace cables everywhere.
UWB is still new and just now
emerging from development. But we
should see some real consumer products using it this year. The Bluetooth
SIG is expected to adopt UWB for their
next higher speed version in the coming years, further increasing its usage.
RFID is the radio equivalent of a bar
code. A tiny radio transceiver and a
memory containing an ID number and
other information is built into a tiny
chip with an antenna to create what is
called an RFID tag. The tag can be pasted on almost any item. When the tag is
brought near an interrogator or reader
unit, the tag transmits its information to
the reader. A neat feature is that the tag
has no battery or other power supply.
Instead, the tag draws its power from
the radio signal radiated by the reader.
That RF is rectified and filtered into DC
to power the tag. The tag then transmits
its data back to the reader. The power is
very low so read distances are only a few
inches to a couple of feet max. Active
tags with a battery give more power and
can be read over a longer distance.
The original tags operated on 125
kHz, but the range was very short.
Longer range units use the license-free frequency of 13. 56 MHz. Newer,
second-generation tags operate in
the 800-900 MHz UHF range and have
a range of many feet.
RFID tags are designed for a wide
range of uses. Inventory control in a
warehouse, asset tracking, as well as
shipping and handling. RFID is also
used in automatic toll collection and
payment for gasoline at the pump and
automated entry to parking areas. It is
used in employee ID cards that are read
to allow entry to the workplace. RFID
has already been adopted by the
military and many large retailers like
Walmart. Look for others to use it as the
volume increases and tag prices drop.
Infrared (IR) wireless uses infrared
light to transmit data. Most TV and
other remote controls use IR. Yet, it can
be used for other data over short
ranges. It has been used in printers,
PDAs, laptops, and a few other devices.
Data rates of 4 and 16 Mbps are available. The biggest limitation is the range
which only extends up to several feet
and there has to be a clear line-of-sight
path because IR is light and can be
blocked unlike radio waves. IR wireless
is just a niche, but for some applications, it is a good fit. Besides, it is probably the cheapest wireless you can get.
This is a relatively new wireless
technology pioneered by Sony and
Philips. The term near-field refers to
the radio waves directly around the
antenna which is mainly a magnetic
field. The far field is made up of both
the electric and magnetic fields. NFC is
designed for very short range operation, typically less than 20 centimeters
or roughly about eight inches. That is
short range. NFC is similar to RFID in
that it can be a passive communication
where a device communicates with a
reader or base station and derives its
operating power from the transmitter.
An active mode assumes that the
device is also self powered, giving the
device a longer transmission range.
Some of the items to be NFC-enabled
are cell phones, PDAs, and digital
cameras. A smart card can also use it.
NFC uses the worldwide unlicensed
frequency of 13. 56 MHz. The devices
transmit identification information
such as name and address and things
like a credit card number. The data rate
is 106 kbps, 212 kbps, or 424 kbps,
depending on range and application.
NFC has several potential applications. First, it can be installed in a
cell phone or PDA and used to make
payments, buy tickets, or gain entry to
certain places. In this way, it acts
almost like an RFID tag. NFC is also
targeted at uses such as establishing
other wireless communications links
such as connections between two
Bluetooth or Wi-Fi enabled devices
that do not initially talk to one another. By simply bringing the two devices
close together, they exchange protocols and other connection data to
establish a network, then the devices
launch into communications by way
of Bluetooth or Wi-Fi. Look for NFC
this year and expanding next year.
ISM BAND RADIO
Let’s not forget those simple
radios using the Industrial-Scientific-Medical (ISM) bands from about
300 to 500 MHz. Typical operating
frequencies are 315 and 433 MHz. This
is where your garage door opener and
remote keyless entry devices work.
Another common application is the
wireless temperature sensor and wireless tire pressure measuring systems
in some cars. When very simple data
must be transmitted and no complex
multilayer protocol is necessary, this
is the wireless to use. The chips are
cheap, plentiful, and very easy to use.
Is wireless everywhere? Not yet,
but we are well on the way. And an
amazing fact is that multiple radios
are showing up in some devices,
especially cell phones. Besides the
cell phone transceiver, some
handsets also contain the Bluetooth
transceiver as described earlier. Some
of the more exotic cell phones also
contain a Wi-Fi transceiver that can
be used to make Voice over Internet
Protocol (VoIP) calls through any
access point or hot spot. Some cell
phone manufacturers are even thinking of putting ZigBee in a cell phone
for remote control of home devices.
And certainly look for NFC in phones.
A cell phone could end up with five or
six radios inside. The challenge will
be to keep them from interfering with
one another. Is that too much of a
good thing or what? NV