For better or worse – and
mostly for better, I think – 2012 was the Year of Spectrum.
We saw a series of
amazing announcements about step-changes in the number of megabits we can run
through a given amount of satellite spectrum.
In 2007, the research firm NSR coined a new term, "high-throughput
satellite.” Until 2012, high throughput
was pretty much synonymous with the Ka band of frequencies, able to deliver
more bits per hertz due to their shorter wavelengths and re-use of frequencies
among spotbeams, from Wildblue and ViaSat-1 to Eutelsat’s KA-SAT, Hughes’
Jupiter, and Ka-band payloads on Avanti, Arabsat, Jabiru, SES, Inmarsat and O3B
But then Israel’s Novelsat
and Belgium’s Newtec introduced modulation technologies that began a
well-publicized race toward higher and higher speeds: 250, 310, 500 Mbps and
beyond. And in June, Intelsat said that
its next generation of EPIC spacecraft would be high-throughput satellites
employing the frequency re-use and architecture of the Ka-band birds in a mix
of frequencies: hemi or regional beams in C and spotbeams in Ku and Ka. No longer an outlier, the HTS design has now
In WTA’s Teleports
in a Gigabit World report, we
said that it is only a matter of time before one of these wizards announces the
ability to put a gigabit per second through a transponder. As ViaSat founder Mark Dankberg put it in
that report, "What we are doing is to give you lots and lots of bandwidth to
make your customer happy. You are no
longer trying to squeeze high performance out of a small amount of resource,
and you are suddenly in a whole new world.”
But this brave new world
also brings new challenges – and radio frequency interference is certainly
one. The harder we push the spectrum to
meet the world’s apparently limitless demand for bandwidth, the worse
interference is likely to grow as an issue.
At the end of last year,
I was in Dubai for the annual meeting of the Satellite Interference Reduction
Group and saw a starting presentation.
SES and Intelsat have recently upgraded their capabilities for capturing
information on interference and its sources, and showed the meeting their first
results. They confirmed something I
suspected ever since I did interviews for two of WTA’s What
Customers Want reports, one on the media market and the other on
I learned that interference
is a big issue for broadcasters, because they occupy full transponders carrying
programming that earns them revenue. In
response to a question about interference, enterprise customers basically said
"what interference?” Their needs are met
by fractional slices of bandwidth, and the impact of interference on them is
not sufficient to get their attention.
So the early results announced by the satellite operators were startling
but hardly a surprise: broadcast traffic, including SNG, generates only a tiny
percentage of persistent interference.
By far the biggest source is VSAT carrying enterprise traffic. Which means that, no matter how hard
broadcasters work on reducing the interference they cause, they can’t fix what they
mostly haven’t broken.
And finally, in 2012, we
began looking forward to 2015, when the World Radiocommunications Congress
reconvenes and the mobile industry once again comes, like Oliver Twist, saying
"Please, sir, may I have some more?” The
satellite industry did a good job of defending C-band from land-grabs at the
last WRC, and will have to repeat the performance in 2015.
The prospect of 2015
makes the following year-end news item a comfort.
Two professors at the
University of California, Riverside have developed a new method that doubles the efficiency of
wireless networks. Mobile traffic
operates today in half-duplex mode: it sends on one channel and receives on
another. A full-duplex circuit sends and
receives simultaneously on the same channel, doubling the efficiency. Except that we don’t know how to do it in 3G
and 4G. Professors Yingbo Hua and Ping
Liang have developed a solution called time-domain transmit beamforming, which
prevents the simultaneous incoming and outgoing signals in a full-duplex
circuit from interfering with each other.
It apparently does so in a manner consistent with existing mobile
technologies. Doctors, call your patent
Don’t’ you know there’s a
spectrum crunch? The people want mobile
voice and data, and we need your bandwidth now!
By 2015, maybe not so much.