Digital Signal Processing Reference
In-Depth Information
2.3.1.2 IEEE 802.19 Coexistence Technical Advisory Group
The IEEE 802.19 Technical Advisory Group deals with coexistence between un-
licensed networks, which is hence applicable to many of the IEEE 802 wireless
standards. The first example of wireless coexistence was between IEEE 802.11 and
IEEE 802.15.1 (Bluetooth), both operating in the 2.4 GHz ISM band. Coexistence
for those networks was first addressed in the IEEE 802.15 Task Group, which pro-
duced a Recommended Practice on Coexistence of IEEE 802.11 and Bluetooth.
Since March 2006 the IEEE 802.19 TAG addresses coexistence between wireless
standards for unlicensed wireless networks under development within IEEE 802.
When a new standard (or amendment to a standard) for an unlicensed wireless net-
work is being developed the working group may develop a Coexistence Assurance
(CA) document that is reviewed the IEEE 802.19 TAG. At this moment, CA docu-
ments exist for IEEE 802.15.3c, IEEE 802.16h, IEEE 802.11y, IEEE 802.11n, IEEE
802.15.4a and IEEE 802.15.4b.
TV bands are generating a lot of fuss and interest within IEEE 802 because work-
ing groups like 802.11, 802.15, 802.16 and 802.22 have their eyes on this new (and
very good) part of the spectrum. The IEEE 802 Executive Committee approved the
formation of a “TV white space coexistence study group” in the 802.19 Coexistence
Technical Advisory Group. The Study Group stopped its activity after the March
2009 meeting. IEEE 802.11af is the new study group focusing on a PHY and MAC
for the TV bands.
2.3.2 The TV White Spaces: Spectrum Sharing in Licensed Bands
The main interest in the TV bands is driven by the worldwide switchover from
analogue to digital terrestrial TV which will release a large portion of spectrum
known as the “digital dividend”, and might also make available the guard bands
between existing or new broadcasting channels (the so-called TV White Spaces or
TVWS) available for opportunistic use. These frequency bands are very valuable as
they provide propagation characteristics that enable signals to penetrate thick walls
and travel long distances. The general consensus worldwide is that at least part of
this digital dividend and TVWS spectrum should be allocated for mobile broadband
services.
The debate on these so-called 'white spaces', is regularly grabbing headlines in
the media with a noticeable interest from and role for new players in the wireless
field. The debates centers on the free use of White Space Devices (WSD), i.e. de-
vices that could opportunistically make use of free spectrum for various goals. Par-
ties in favor of these devices see major opportunities for the freed up spectrum,
including more mobile broadband services, offering better quality of service, to
more users. Traditional users of the freed-up spectrum bands and adjacent spectrum
bands such as broadcasters are concerned about the consequences of this type of un-
licensed use that could interfere with licensed use. They demand a highly regulated
approach.
