So as per Section 4.2.1, this system uses
simple amplitude detection [sqrt(I^2 + Q^2)] above a predefined threshold in
the time domain to detect the presence of another network. This might be fine
for existing wireless technologies, such as simple OFDM (most people don’t
normally characterize OFDM as “simple” J), but beamformed
networks may be nearby that simple amplitude detection won’t detect
unless it implements a beamformed receiver in the opposite direction, which I
suspect would be unlikely.
Furthermore, modulation techniques may be
developed for these bands, using lots of coding, that permit data transmission close
to 0 dB SNR. These transmissions will not be detected either, regardless of
which direction you point the beam.
I don’t wish to sound like a curmudgeon,
and I recognize that such fancy modulation systems may never be developed for
these bands, but if we accept such a simple detection system, then it
guarantees that we will never be able use them even if we wanted to. On the
other hand it’s unrealistic to require every device in this band to
include a full-blown SDR with wide-band I-Q spectrum analysis capability.
-- Ed Reuss, Principal Engineer, Advanced
Technology Group, Plantronics, Inc.
From: Bruce Kraemer
[mailto:bkraemer@xxxxxxxxxxx]
Sent: Thursday, August 20, 2009
7:25 AM
To: STDS-802-19@xxxxxxxxxxxxxxxxx
Subject: Re: [802.19]
Microsoft/Harvard Protocols to Fix WhiteSpace Interference
Richard et al,
The technology description can be found
here.
http://research.microsoft.com/pubs/80952/whitefi.pdf
Bruce
From: Richard Paine
[mailto:richard.h.paine@xxxxxxxxx]
Sent: Thursday, August 20, 2009
9:45 AM
To:
Subject: [802.19] Microsoft/Harvard
Protocols to Fix WhiteSpace Interference
Everybody who has been
working on TVWS in IEEE 802 should read this, the source document, and the
related material.
From
FierceBroadbandWireless:
-------------------------------------------
Microsoft claims new protocol fixes
interference problem for white-space devices
|
|
By Lynnette Luna |
Researchers
from Microsoft and
The
researchers believe the protocol could enable devices to avoid interference in
white-space spectrum--those unused slivers of spectrum in the 700 MHz band
between spectrum used by broadcast TV stations. The FCC approved the use
of white-space devices last November on the condition that they don't
interfere with nearby services, such as broadcast TV and wireless microphones.
White-space devices are supposed to undergo a rigorous certification process
before it is authorized. The vision for white space is to create super WiFi
technology. The broadcasting industry has vigorously opposed any use of
white-space devices, citing interference concerns. It hasn't been satisfied
with the FCC's conclusion that interference won't be a major problem.
Microsoft and
Harvard researchers presented their ideas this week at the ACM SIGCOMM 2009, a communications
conference held in
Microsoft
recently obtained an experimental license from the FCC to build a prototype
White-Fi system on the Microsoft Research Campus in
For
more:
- read Cnet
Related
articles:
White
space: Dell to make laptops; Google downright giddy
FCC unanimously approves
unlicensed white-space devices
Microsoft
intensifies white-space lobbying efforts
Read more about: WiFi,
White-Fi,
white
space, protocol
Richard Paine
Success is getting
what you want, happiness is liking what you get!
Phone: 206-854-8199
Skype: richard.h.paine
Email: