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RE: stds-80220-requirements: Spectral Efficiency (4.1.2)

Title: Message
All,
 
Minimum edge guard band is a real-life requirement that impacts the cost to operators. Moreover, different technologies require different edge guard bands. Hence, edge guard band can be an important differentiator.
A way to estimate edge guard bands that does not require study of all possible air interface combinations may be the following compromise:
 
For simplicity, assume that:
However, make further assumptions that allow an independent operator to use the neighbor spectrum, in particular:
Spectral efficiency can then be estimated for two block sizes (1.25 and 5 MHz, say) and a statement can be added on how efficiency is expected to scale with block size.
 
Regards

Jheroen Dorenbosch

-----Original Message-----
From: Kapoor Samir [mailto:S.Kapoor@flarion.com]
Sent: Wednesday, November 19, 2003 7:00 AM
To: 'Joanne Wilson'; Shively, David; stds-80220-requirements@ieee.org
Subject: RE: stds-80220-requirements: Spectral Efficiency (4.1.2)

Dave/Joanne,
I agree that knowing the required edge guard band requirements is important from an operator perspective but my concern is that by including them in spectral efficiency calculations, we will make it very difficult to do comparisions between different air interface technologies.  As pointed out below, guard bands not only depend on many deployment specific factors (size of bands, which other technlogy is in the spectral vicinity, duplexing method, operator/vendor engineering rules etc) but there are no fixed values since trade-offs can often be made between performance impact and guard band widths. Throwing in both TDD and FDD systems in the mix introduces even more non-uniformity. Using inter-carrier spacing (i.e. required spacing between same carriers, or nominal bandwidth) can make this comparision much more straightforward and still be a useful comparative metric for a wide variety of situations. Perhaps there is another way to capture the guard band requirements in the evaluation criteria or requirements so that a complete picture is available at least for typical or common deployment situations.
Regards,
Samir
-----Original Message-----
From: owner-stds-80220-requirements@majordomo.ieee.org [mailto:owner-stds-80220-requirements@majordomo.ieee.org]On Behalf Of Joanne Wilson
Sent: Tuesday, November 18, 2003 4:24 PM
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