Reza, attached are some of my comments to your
original message.
Regards,
Jim Tomcik
At 06:20 PM
8/1/2003 -0400, Reza Arefi wrote:
Resubmission of the
previous message so that it gets into the archives.
Reza
- -----Original Message-----
- From: owner-stds-80220-coexistence@majordomo.ieee.org [mailto:owner-stds-80220-coexistence@majordomo.ieee.org]On
Behalf Of Reza Arefi
- Sent: Thursday, July 31, 2003 2:22 AM
- To: 802. 20 Coex CG (E-mail)
- Subject: Coexistence CG Kick-off
- Dear Coexistence CG participants,
-
- In its July meeting, 802.20 WG chose to form a Coexistence
Correspondence Group to "study and create a consensus recommendation on
how to address the issues of coexistence of future 802.20 systems with
other wireless technologies deployed in the licensed bands below 3.5 GHz."
- There were two contributions on the issue of coexistence presented to
the WG.
-
- - C802.20-03/72,
by Reza Arefi
- - C802.20-03/61r1,
by Jim Tomcik, Ayman Naguib, and Arak Sutivong
-
- The above two contributions, while consistent on acknowledging the
challenges of the task, presented different views on how to address the
issue within 802.20. While document 72 asked for a Coexistence Task Group
within 802.20 to deal exclusively with the issue in parallel to the air
interface work, document 61r1 suggested that the matter should be studied
by the entire body in series prior to the air interface
work.
Reza, I believe the above statement is somewhat in error.
Document 61r1 suggests that the matter of coexistence should be incorporated
into the standards development process, not necessarily "studied in series
prior to the air interface work." This could be accomplished through
suitable requirements, or evaluation criteria, so that we have some idea how
different technical proposals "stack up" when deployed (for example) adjacent
to current systems.
Reza> Jim, If you want to characterize your opinion exactly
as in the above it is perfectly fine. But I see no error in the way I
presented it. If the coexistence work is to be incorporated into the
requirements and evaluation criteria, this means that it should
be done "prior to air interface work", as I put it, since these two
activities are being done prior to looking at any air interface
proposals. In 802 terms, the air interface development starts when
the WG issues a Call for Proposals for the air
interface.
-
- The goal of the CG is to come up with a recommendation on the best way
to address coexistence within the WG. The coexistence analyses themselves
are outside the scope of the CG and are left to a Coexistence document
that 802.20 is likely to produce. Therefore, I see the output of this CG
as a concise document (probably one page) that includes a clear
recommendation to the WG and the rationale behind that recommendation.
Yes, I think this is what we agreed to do. The document
may as you note be 1 page.
- The way I propose to go forward is to have open discussions on the
reflector for a while so that we get a sense of the range of opinions and
the amount of interest in the subject. I will submit to the group a
compilation of all views prior to our first conference call on August 15.
I propose the following four specific topics for discussion on the
reflector so that we stay focused on what we are chartered to do. Please
feel free to choose from the list or suggest other related topics I might
have missed.
I may not be able to make the conference call on August 15
due to other commitments. I will try to get one of our other 802.20
members to attend.
- Given the fact that 802.20 will be deployed in licensed bands, does
802.20 WG need to address coexistence or should the matter be left to the
regulatory regime in each country?
I don't believe this is a strictly regulatory question - we need to
address the effects of a new technology deployed in bands that are currently
being used by other technologies. A good start would be to scope the
problem by defining the targetted bands of operation and mode of operation
anticipated as of this date.
Reza> Jim, as stated in doc 72, I also see the identification
of a few bands for detailed analysis as one of the first steps
that a
Coexistence task group should take.
- In case the WG chooses to take up the task, should it create a
"Recommended Practice" (one containing the word "should") or a "Guideline"
(one containing the word "may")?
I don't believe a separate document is what's needed for
coexistence. Rather we need to define either requirements or evaluation
criteria so that coexistence is properly considered as 802.20 considers
technology alternatives in building an air interface standard.
Reza> Jim, evaluation criteria document
does not cover this topic.
- What are coexistence related issues that need to be resolved before
the work on the air interface could begin?
Some issues to be considered (again, as we develop an air interface) are
the impacts of 802.20 technology deployed adjacent to (in frequency) each
likely existing technology (I'm thinking primarily mobile wireless, satellite,
and GPS). Co-channel interference impacts remains an open
issue.
If FDD and TDD operational bands remain undefined, the work
should also take into effect the impacts of TDD in FDD bands, and Vice
Versa.
There may be other issues, but these are the initial ones I
see.
Reza> How can one analyze the impact of 802.20
technology on systems deployed in other bands before its air interface is
drafted? Or how can it be done at the evaluation criteria level when it is not
even clear what kind of technology 802.20 is going to be? What kind of
multiple access, random access, etc.? We don't know any of these until past
the Call for Proposals when we have a working draft of the air
interface.
In my opinion, however, there are certain things the group can
do about coexistence before we get to that stage. For instance, we can look at
various bands below 3.5 GHz allocated to the mobile service and their
regulatory situation. We can also identify coexistence scenarios in such bands
in terms of co-channel or adjacent channel interference scenarios. Such
information will help later on with the interference simulations. While such
activities are important, they are not prerequisite to the air interface work
and are not intensive enough to involve the whole WG. That's why I suggested
that a subset of the WG (a Task Group in 802 terms) gets
involved.
- Should the coexistence work focus on the coexistence of 802.20 TDD and
FDD variants as the primary source of interference problems? Or should it
focus on coexistence with other systems?
Could you elaborate this a little bit? I think 802.20 TDD and
FDD should be considered as interferers, certainly to other systems. In
addition, the opposite effect - existing systems in adjacent channels
impacting 802.20 TDD or FDD is of interest.
Reza> Jim, The situation with 802.20 TDD and FDD will
be very much similar to WCDMA (FDD) and UTRA-TDD. There will be cases that
802.20 TDD and FDD technologies operate in adjacent bands in the same
geographical area, or in the same bands in adjacent geographical
areas. In these cases, the base-to-base and mobile-to-mobile
interference could be severe and needs to be analyzed so that appropriate
guardbands be determined. As a matter of fact, a lot of the
coexistence efforts in 3GPP revolved around this topic. I will start an
email thread on this issue.
Looking forward to your
participation.
Regards,
Reza
..................................................................................
James
D. Tomcik
QUALCOMM,
Incorporated
(858)
658-3231 (Voice)
(619)
890-9537 (Cellular)
From:
San Diego, CA
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