Datasheet

SaskTel Turns to Tektronix RSA306B USB-Based
Spectrum Analyzer to Track Down Interference from
European DECT Wireless Handsets
Interfering DECT phones
DECT stands for Digital Enhanced Cordless Technology, although
some might suggest that the “E” actually stands for European.
And, in fact, the DECT standard for cordless telephone systems
did originate in Europe. Due in part to this development path,
there are slight differences in the frequency ranges for European
DECT phone and their North American counterparts. The
differences may be slight, but they are significant if you are an
information and communications technology (ICT) provider like
SaskTel.
Like other cell service providers across North America, SaskTel
faces ongoing problems with European DECT phones. When
people move from Europe to the Canadian province of
Saskatchewan where SaskTel supports more than 614,000 cell
service customers, they often bring their DECT phones with them.
From a consumer perspective, the phones work fine and they
generally have no idea that approximately 10 MHz of the
unlicensed spectrum used by their wireless handsets overlaps
with SaskTel’s licensed spectrum.
For SaskTel and its customers, however, it’s a different story.
“Interference shrinks the footprint of a cell site, it degrades the
download and the upload speeds, and when it shrinks the
footprint of the site, it’s kind of a snowball effect,” says John
Davidson, a Technical Assistant in SaskTel’s Technology
Division. “In some cases the phones have to transmit with more
power to get back to the site, and that in turns affects more and
more phones in the area. And it might not just affect one site,
depending on the number of phones in the area it might affect a
number of sites in a city setting. The ability to track down the
source of interference and do it quickly and in a timely fashion is
important.”
By monitoring changes in receive total wideband power (RTWP)
at its cell sites, SaskTel can see when interference is occurring
and the general location using a tool called splunk. They then
dispatch Davidson or other engineers and technicians with test
equipment and vehicles to start the hunt. The vehicles are
typically equipped with traditional swept tune spectrum analyzers
along with a variety of directional antennas. In other words, a
typical set up for interference hunting applications.
But when it came to European DECT phones, tracking down
interference sources was hardly quick or timely using this
equipment. The problem, according to Davidson, was that “if the
phone was not transmitting at the time your spectrum analyzer
sweeps across that frequency, you wouldn’t know that it was
there.
Customer Solution Summary
CHALLENGE
––
SaskTel, the leading information and
communications technology provider in
Saskatchewan, faced interference problems from
DECT wireless handsets coming over from
Europe – they overlap with 10 MHz of SaskTel’s
licensed spectrum. Trying to find these handsets
proved to be very difficult for the provider’s
interference hunters using a swept-tuned
spectrum analyzer.
SOLUTION
––
SaskTel’s team of interference hunters adopted
the Tektronix RSA306B USB-based real-time
spectrum analyzer, because it allows them to
immediately see signals from the rogue
European-spec DECT phones and quickly
eliminate a frequent source of interference.
BENEFITS
––
Interference is a major problem for cell providers
because it shrinks the footprint of a cell site,
leading to a snowball effect and overall degraded
service for customers. With the RSA306B on
hand, SaskTel can now quickly track down
interference sources and maintain high-quality
service levels.