I
concur with Bob Love's advice to 'keep it simple' and with Joann that the
bandwidth is the spectral width that contains 99% of the emitted power.
This is consistent with the FCC definition.
Joseph
Cleveland
-----Original Message----- From:
owner-stds-80220-requirements@majordomo.ieee.org
[mailto:owner-stds-80220-requirements@majordomo.ieee.org] On Behalf Of
Joanne Wilson Sent: Monday, November 24, 2003 11:48
AM To: Shively, David;
stds-80220-requirements@ieee.org Subject: RE:
stds-80220-requirements: Spectral Efficiency (4.1.2)
David,
Since we agree that a
consistent approach for all technologies is the way to go,I think now we are just struggling
a bit with the details of how to achieve it.To some extent, this discussion
has become as much about the evaluation process(which is the purview of another
CG) as it is about how to define "network-wide bandwidth". In keeping
with Bob Love's good advice not to dive to deeplyinto the details at the requirements
level, let's trust (or encourage) the EvaluationCG to create a process that provides a
consistent approach to simulating theperformance of the various proposals
within a fixed block size (possibly 5 MHz,which seems to be preferred by many)
and takes into consideration the
need to confinethe transmitted
signal energy, say at the 99% level, to within that fixed block.To calculate throughput in a
specific scenario, the amount of spectrum that
must be allocated to guardbands to meet that 99% level would be subtracted from the total available spectrum prior to multiplying by the calculated spectral
efficiency. I believe the 99% numberguarantees that the variations in
guardband requirements from one technology to the nextwon't be all that significant. It
appears to me that this level of detail should be madea proposal to the Evaluation CG and the
definition of network-wide
bandwidth in theRequirements
document could be left as is, or at least it should be less detailed than the
above.
Best regards,
Joanne
-----Original Message----- From:
owner-stds-80220-requirements@majordomo.ieee.org
[mailto:owner-stds-80220-requirements@majordomo.ieee.org]On Behalf Of
Shively, David Sent: Wednesday, November 19, 2003 8:35
AM To: stds-80220-requirements@ieee.org Subject: RE:
stds-80220-requirements: Spectral Efficiency (4.1.2)
Hi Robert and
Dave,
As Dave
had pointed
out:
---------------------------------
"There seemed last week some confusion about
channelisation, freq. arrangements and the
tabular set of likely spectrum amounts to be
entertained for viable deployments and all coupled
with the related issue of the evaluation
criteria."
-----------------------------------------
I
completely agree. This what I was trying to clarify. It doesn't
make sense to discuss the
adoption of specific spectral efficiency values
(e.g. 1 or 2 bps/Hz/sector) without a consistent
way to do the calculation. Of course, this issue also comes up when
performing comparisons
to other
technologies.
Best regards,
David Shively
Cingular Wireless
-----Original Message----- From: Robert D. Love
[mailto:rdlove@nc.rr.com] Sent: Tuesday, November 18, 2003 5:44
PM To: djames@oak-global.com; 'Joanne Wilson'; 'Shively, David';
stds-80220-requirements@ieee.org Subject: Re:
stds-80220-requirements: Spectral Efficiency (4.1.2)
David, you have expressed my concern accurately. As we get into
the detailed evaluation phase it will become more apparent how we must
modify our first set of evaluation criteria to fairly and accurately
account for the range of variability that our candidate technologies
exhibit. Therefore, we should not attempt to drill down too far, nor
be too exclusive of other options as we establish our initial
requirements.
Best regards,
Robert D. Love President, LAN Connect Consultants 7105 Leveret
Circle Raleigh, NC 27615 Phone: 919
848-6773 Mobile: 919 810-7816 email: rdlove@ieee.org Fax:
208 978-1187
Yes,
you just beat me to the e-mail on this one. This is really tricky,
rather like determining the length of a piece of string, taking into
account all the possible permutations.
On
the latter point, I did not at last week's meeting also raise publicly
the related question of suitable frequency bands for MBWA (I'd rather we
called it PWDSL, for reasons I gave last week). There are many
other freq bands possible internationally, particularly if the WG can
overcome the tendency to slip back into a mindset over always thinking
in terms of 2G/3G spectrum. Last week presentations were
restricted to just PCS and similar bands (after all we were in
USA). But there is other spectrum, and there are many other new
operators to emerge (I know, I am working with some
..).
As if
that is not presenting enough permutations, there is also
the issue we discussed some on what sort of "default" spectrum
should be used for a sensible comparison (or set of such ?) for spec.
efficiency. There seemed last week some confusion about channelisation,
freq. arrangements and the tabular set of likely spectrum amounts
to be entertained for viable deployments and all coupled with the
related issue of the evaluation criteria.
So my
provocative suggestion is - as you imply - that the regulatory aspects
be kept separate here, that the spec efficiency be defined in terms of
"number of carriers deployed" (declared) "and the allocation
block size"; that something like 10 MHz (TDD) or 2 x 5MHz (FDD) be taken
as a baseline usage for all this for the purpose of assessment.
If folk want another higher (or lower) chunk of spectrum, so be
it. In any case, when it comes to evaluation of spec.
efficiency this has to be assessed along with other related
parameters which in turn relate to how one might have to determine
and invoke guard bands or other measures (and here some bands have
modest sharing rather than so-called co-existence issues).
Proposals will clearly have to explain how the spec. efficiency may or
may not scale but may be piecewise incremented (pilots, BCH,
correlation and other considerations
etc)
So
I'd agree with your text re "...defining the spectral
efficiency ......... should be done based solely on the technology
itself". Of course that is not the end of it, one has to supply
all the other material, too. So again back to the
notion: ".......unique carriers deployed in the network, including
anyrequired spacing between
carriers.
Certainly it seems to make things a lot simpler
if one takes the aggregate DL, UL spec. efficiency /offered traffic
rather than keep carrying the two separately, for there are so many
other similar considerations and permutations for this,
too.
I think Bob Love made a valid point last week
in this respect. There is endless pre-occupation in some quarters (and I
can see why !) over pre-defining exactly how this calculation or that is
to be done and under a thousand permuted scenarios. I think his
valid point was that we should move ahead more firmly, not try to
settle each and every parameter prematurely; many are
inter-related, and in the longer term the requirements,
the baseline scenarios, the eval. criteria, the proposals, the
assessment and discussed possible adjustment constitute a somewhat
iterative process. (Bob, tell me if I misconstrue,
please.)
BR,
Dave
-----Original Message----- From:
owner-stds-80220-requirements@majordomo.ieee.org
[mailto:owner-stds-80220-requirements@majordomo.ieee.org] On Behalf
Of Joanne Wilson Sent: 18 November 2003
21:24 To: Shively, David;
stds-80220-requirements@ieee.org Subject: RE:
stds-80220-requirements: Spectral Efficiency
(4.1.2)
Dave,
It seems to me that the guardband
requirements that you mentioned are probably that
which
was needed to meet the spectral mask associated with a
given frequency allocation. Those are
regulatory
matters that are outside of the purview of 802.20 to
set and impossible for us to know without
explicit
knowledge of the market and band of deployment. For
the purpose of defining the spectral
efficiency
of the air interface, I believe it should be
done based solely on the technology itself. In your
example,
you cite cdma2000 as having several different carrier
bandwidths depending on the number of carriers
deployed and the allocation block size.
Based on that, I don't see how one could make a valid
assessment
of cdma2000's spectral
efficiency. The PCS example may just be a deployment issue
-- in a 5 MHz
block assignment they were able to deploy
three 1.25 MHz carriers with 625 kHz guardbands on the
edges.
A good
test case would then be to ask
how many carriers could be deployed in a 10 MHz block
assignment.
My guess (one of the cdma2000 suppliers
or operators could provide a more definitive answer) is
that
they could deploy more than 6 carriers
-- in fact, probably 7 carriers with 625 kHz
guardbands on the
edges. In that case, by your method the
cdma2000 carrier bandwidth would be about 2.14 MHz and
not
2.5 MHz..
All this is to say that I think the guardband
issue, at least with respect to adjacent block
protection,
completely muddies the calculation
of the spectral efficiency for the air
interface.
Regarding UMTS, it was my understanding that
ETSI had a specific work item to modify the
UMTS
air interface so that it could be deployed
with the US PCS allocation in a 5 MHz block size.
Again,
someone from that community can correct me if
that was not the case.
Best
regards,
Joanne
Wilson
-----Original Message----- From:
owner-stds-80220-requirements@majordomo.ieee.org
[mailto:owner-stds-80220-requirements@majordomo.ieee.org]On
Behalf Of Shively, David Sent: Tuesday, November 18,
2003 1:59 PM To:
stds-80220-requirements@ieee.org Subject: RE:
stds-80220-requirements: Spectral Efficiency
(4.1.2)
You are correct that my intention is to define a way to
evaluate spectral efficiency in a consistent
manner.
In the case of cdma2000, the individual
channels can be placed directly adjacent to one another but
there
is still a required guard band on either
end of these channels. For 1900 MHz systems, the guard
band
on each end is typically 625 kHz, for a
total of 1.25 MHz. Thus, for a single cdma2000
carrier the total
spectrum requirement is 0.625 kHz +
1.25 MHz + 0.625 kHz = 2.5 MHz. For 2 carriers, the
total
spectrum requirement is 3.75 MHz and for 3
carriers the total is 5 MHz. As you noted, the
requirement
may be less at 450 MHz but there is still a
clear requirement for some guard bands and this would
impact
the
calculation of spectral
efficiency.
For UMTS, the chip rate is 3.84 Mcps so the
basic bandwidth requirement is commonly quoted
as
3.84 MHz. This would be the -3 dB bandwidth
or, rather, the equivalent noise bandwidth.
I do not know what you refer to in terms of
modifications for the US PCS bands. The 3GPP
standards
do include the definitions and
specifications for the 5 MHz frequency blocks that are part of the
bandplan
for the US PCS bands. The
3.84 Mcps carrier completely fits into the 5 MHz block since
there is "extra"
space on either
side.
The bottom line is that the spectral
efficiency calculations should be done as consistently as
possible.
From a network operator's perspective, what
interests me is what spectrum efficiency can I get in
a
certain amount of deployed spectrum
(including guard bands).
The alternative approach would be do use
only the carrier bandwidth without any guard bands.
However,
in this case, for example, the UMTS
bandwidth would be 3.84 MHz rather than 5
MHz.
David Shively
-----Original Message----- From:
Joanne Wilson [mailto:joanne@arraycomm.com] Sent:
Tuesday, November 18, 2003 12:38 AM To: Shively, David;
stds-80220-requirements@ieee.org Subject: RE:
stds-80220-requirements: Spectral Efficiency
(4.1.2)
Dave,
In principle, I agree with your underlying premise which I
believe is that all proposals should state their
overall
bandwidth requirements in a consistent way. However,
I don't think your example is quite
correct. For example,
I know that three cdma2000 carriers can be deployed
in less than 2x5 MHz of spectrum (e.g.
cdma450 deployments
which I believe are in about 2x4.5 MHz blocks) but
W-CDMA cannot be deployed in less than 2x5
MHz and in fact,
I understand that it had to be modified to be
deployable in the US PCS bands that are multiples of 2x5 MHz block sizes.
So,
I don't believe that the 5 MHz W-CDMA channel bandwidth
includes guardbands.
I believe it would be impossible to determine what
would be the needed guardbands for protection of adjacent block
licensees.
I think it would be make sense to include whatever spacing
would be needed between multiple carriers in a
single
deployment.
If you agree, how about the following
approach?:
"The network wide
bandwidth is the total spectrum in use by the unique carriers
deployed in the network, including any required spacing
between carriers."
Agree?
Best
regards,
Joanne
-----Original Message----- From:
owner-stds-80220-requirements@majordomo.ieee.org
[mailto:owner-stds-80220-requirements@majordomo.ieee.org]On
Behalf Of Shively, David Sent: Monday, November
17, 2003 4:06 PM To:
stds-80220-requirements@ieee.org Subject: RE:
stds-80220-requirements: Spectral Efficiency
(4.1.2)
Regarding these definitions, it should be
clearly understood whether or not guard
bands are accounted for in the calculation of spectral
efficiency. For UMTS (W-CDMA), the
channel is usually quoted as being 5 MHz
wide. In this case the guard bands have been
included. However, for cdma2000 1X
(and IS-95) the channel is usually quoted as being
1.25 MHz wide which does not include the
necessary guard bands.
I propose the following:
Network Wide Bandwidth: The network wide
bandwidth is the total spectrum in use
by the unique carriers deployed in the network, including any
required guard bands.
Best regards, David
Shively -----------------------------------------------------------
Dr. David Shively Cingular Wireless 5565 Glenridge
Connector, Mail Stop 950 Atlanta, GA
30342 Phone: 404 236 5909
Mobile: 404 285 5731 FAX: 404 236 5949 email: david.shively@cingular.com pager: dshively@imcingular.com
-----Original Message----- From: Humbert, John J [NTWK SVCS] [mailto:JHumbe01@sprintspectrum.com]
Sent: Monday, November 17, 2003 12:08 PM
To: stds-80220-requirements@ieee.org
Cc: mike@arraycomm.com Subject: stds-80220-requirements: Spectral Efficiency
(4.1.2)
Below is the latest version of the text that was
developed at the Plenary in Albuquerque along with a list of the
open issues for this section.
*
4.1.2 System Spectral Efficiency (b/s/Hz/sector)
*
The system spectral efficiency of the 802.20 air interface shall
be quoted for the case of a three sector baseline configuration
[Footnote 1]. It shall be computed in a loaded multi-cellular
network setting, which shall be simulated based on the
methodology established by the 802.20 evaluation criteria group.
It shall consider among other factors a minimum expected data
rate/user and/or other fairness criteria, and percentage of
throughput due to duplicated information flow. The values shall
be quoted on a b/s/Hz/sector basis. The system spectral
efficiency of the 802.20 air interface shall be greater than X
b/s/Hz/sector.
* Footnote
1: Since the base configuration is only required for the purpose
of comparing system spectral efficiency, proposals may submit
deployment models over and beyond the base
configuration.
*
Definition: * System spectral
efficiency - System spectral efficiency is defined as the ratio
of the aggregate throughput (bits/sec) to all users in the
system divided by the network wide bandwidth (Hz) and divided by
the number of sectors in the system.
* Aggregate
Throughput: Aggregate throughput is defined as the total
throughput to all users in the system (user payload only).
* Network
Wide Bandwidth:The network wide bandwidth is the total spectrum
in use by the unique carriers deployed in the
network.
* Open items
-
Single value vs. multiple for uplink and downlink
- X
bits/sec/Hz [note 1 b/s/Hz -or- downlink > 2 b/s/Hz/(cell or
sector?) @ 3km/hr ;uplink > 1 b/s/Hz/(cell or sector?) @ 3
km/hr].
- Actual
values of spectral efficiency at higher speeds - TDD/FDD
John J. Humbert 6220
Sprint Parkway Mailstop KSOPHD0504 -
5D276 Overland Park, KS
66251-6118 PCS (816) 210-9611