stds-802-16-tg4: ITU-R Meeting Summary
Hello All:
I have just returned from the ITU-R 8a/9b meetings in Geneva. The meetings
did not resolve any of the 5 GHz frequency allocation issues, in fact they
may have become more complicated due to the increased global interest in
the band. Some points that may be of interest to the 802.16b crowd:
1/ There is a serious issue of co-existence with primary services in the
allocations of the 5250-5350 MHz and 5470-5725 MHz bands for global mobile
services (which include services such as Nomadic). Concerns have been
raised (mainly by the US delegation) that the secondary (mobile) service
users in the upper bands will be detrimental to the operation of the
primary service users which are maritime, aeronautical, and fixed
terrestrial radars. These radars operate globally and License-Exempt 5 GHz
devices (indoor and outdoor) are expected to produce significant
interference. This interference can affect radars which are very far away
(~ 70Km). The European delegates have tried to address this issue by
proposing the use of DFS as a technique that will identify primary users
and force the LE terminals to move off bands occupied by such users. The US
is not convinced that this technique will work, especially in view of the
fact that bi-static radars (in which the transmitters and receivers are
geographically separated) may be used in the future at 5 GHz. The US
delegates also raised the issue that future radars will operate over much
broader bandwidths than conventional radars, further
exacerbating coexistence. This is an issue which potentially complicates
the IEEE 802.16b standard development work, especially the DFS, RSSI, and
CCI concepts that have been discussed. Even though this issue of LE
Terminal/Radar coexistence issue was not resolved at the ITU-R 8a/9b, it is
evident from the level of concern that was expressed by the majority of
delegates, that it will likely have significant impact on future
regulations. LE system designers should follow these developments closely.
2/ The ITU-R 8a/9b delegates reviewed the letter sent by the IEEE 802.16
Standards Group (14 March 2001 IEEE Document 802.16.4-01/08 page 5 signed
by Roger Marks) which contained a request for mutual co-operation between
the ITU-R and IEEE on coexistence issues, however this went nowhere with
a lot of acrimony. The ITU-R could not agree on the content of a response
letter. One of the obstacles to drafting a response was the point, which
was raised many times, that the IEEE 802.16.4 is addressing
LE "Fixed Wireless Access" which is red flag to the ITU-R 8a/9b whose goal
is to establish allocations for mobile services including RLANs. No matter
how many times it was emphasized that the IEEE 802.16b was addressing
nomadic type applications, many delegates refused to deal with the IEEE
802.16 Working Party letter simply because of semantics. The IEEE 802.16b
PAR was often quoted as evidence as to why the ITU-R 8a/9b should not be
involved in mutually discussing coexistence with the IEEE. Within the
agenda of the ITU-R 8a/9b there is little room to discuss License-Exempt
FWA within the context of global mobile service allocations at 5 GHz. In
view of this terminology constraint, it maybe prudent for IEEE 802.16b to
make it clear that it is developing standards for nomadic terminals ( which
are included in the ITU-R definitions of mobile services) so that the
standards being developed are meaningful in the context of the prevailing
focus of the ITU-R 8a/9b on mobile services. Please read Para 4 to see
some of the ITU-R definitions.
3/ The European delegations, which also included the European Space Agency
and ETSI, were firmly against any global outdoor allocation in the
5250-5350 MHz band. The reason they gave was that outdoor applications
would interfere with EESS. The Europeans were in favor of having the
5150-5350 MHz band allocated for indoor applications only. Canada proposed
an EIRP mask (elevation control of EIRP) for outdoor terminals working in
5250-5350 MHz (as well as for the 5460-5725 MHz) band, which would protect
the EESS. The US, did not support the mask, but did support the use of
the 5250-5350 MHz band for outdoor applications. The EIRP mask was
included in a Preliminary New Draft Recommendation document and will be
subject to further discussion. It is interesting to note that the
opposition to the EIRP mask was strongest in the 5250-5350 MHz band,
especially for LE applications. However, there was approval of a similar
mask for the same frequency band for Region 3 licensed applications, where
it was recognized that such a mask would be beneficial and was acceptable
to the EESS supporters, primarily ESA and the US (Jet Propulsion Lab). In
essence, the technical virtues of a mask are recognized. The most
vociferous opposition to the use of an EIRP mask was not that it would not
work, but that the LE terminals to which it was applied could be
inadvertently misaligned causing interference into the EESS.
4/ Some definitions which are being used by the ITU-R in the development
of the global 5 GHz allocations are given below. I suggest that we
re-examine our use of words in the IEEE 802.16b PAR in order to harmonize
with the ITU. This step would make our developments fall in line
with regulatory considerations being discussed by the ITU 8a/9b....and
eventually the WRC 2003.
ITU Radio Regulation definition of "Mobile Service": A radiocommunication
service between mobile and land stations or between Mobile Stations.
Mobile Station Definition: A station in the mobile service intended to be
used while in motion or during halts at unspecified points.
ITU-R F.1399 Vocabulary of Terms for Wireless Access defines Nomadic
Wireless Access as a " wireless access application in which the location of
the end user termination may be in different places but it must be
stationary while in use"
5/ In conclusion the ITU-R 8a/9b developments seem to hold much promise for
LE applications, both outdoor and indoor. There is a process moving toward
the global allocation of 5 GHz bands and significant technical issues have
been raised, but from an engineering perspective, they do not seem
impossible barriers. I believe the IEEE 802.16 b Working Group must follow
these developments very closely and must make an effort to harmonize its
standards with ITU-R definitions. Also, as was impressed on me many times,
the delegates at the meetings ( such as the FCC from the US, IC from
Canada, and Ministry of Communications from Israel) want the private sector
companies which attend the IEEE 802.16 meetings to voice their concerns and
attitudes regarding 5 GHz spectrum allocations....in writing. Basically
they want guidance in their regulatory discussions. The private sector has
been negligent in doing so. These delegates are your representatives. If
we expect to see 5 GHz used for LE outdoor applications, the private
sector must make the effort to tell the representatives to consider
regulations which will foster such technology.
John Sydor
Research Broad Band Wireless
Communications Research Centre
3701 Carling Avenue
Ottawa, Canada
K2H 8S2
Ph. 613-998-2388
Fax.613-9908369
john.sydor@crc.ca