Re: [802.3_EPOC] Exclusion Sub-band Question
When I said ‘fit’ I meant fit without undue waste. I agree the 2MHz on 1MHz spacing can cover everything.
From: Victor Blake [mailto:victorblake@xxxxxxxxxxxxxxx]
Sent: Wednesday, November 28, 2012 10:14 AM
To: Hal Roberts; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_EPOC] Exclusion Sub-band Question
All-
Exclusions will always fit no matter what the minimum exclusion size is, the real question is how much are you excluding that you don’t need to and therefore the wasted band-width? I suppose that’s the same as asking, what’s the minimum spectrum that would need to be excluded due to regulatory reasons or defensively to avoid ingress interference.
-Victor
From: Hal Roberts [mailto:Hal.Roberts@xxxxxxxxx]
Sent: Wednesday, November 28, 2012 11:04 AM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [802.3_EPOC] Exclusion Sub-band Question
Leo,
I didn’t know the adaptive bit loading per subcarrier had already been decided upon. I agree that is a better method, if available.
However now the question degenerates to the minimum size of exclusion zones. Already an example of a 1.75 MHz exclusion has been raised, are there other examples that don’t fit neatly into 2MHz chunks?
Hal
From: Leo Montreuil [mailto:leo.montreuil@xxxxxxxxxxxx]
Sent: Wednesday, November 28, 2012 9:59 AM
To: Hal Roberts; STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: RE: [802.3_EPOC] Exclusion Sub-band Question
Hal,
The exclusion band is a tool for the operator to specify bands to avoid. For example: SC-QAM DOCSIS, set-top out of band channel, pilots, etc.
For plant ingress and CSO/CTB, the adaptive bit loading per subcarriers will address these problem with a finer granularity. We envision the EPoC CLT will send probes downstream (like MoCA) and collect the MER per subcarrier from the CNU and adaptively adjust the bit loading per subcarriers. This is better than excluding these bands.
The exclusion bands are to tell the CLT and CNU to never probe and use a given spectrum.
Thanks
Leo
From: Hal Roberts [mailto:Hal.Roberts@xxxxxxxxx]
Sent: Wednesday, November 28, 2012 10:40 AM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [802.3_EPOC] Exclusion Sub-band Question
Unless Method 2 is a lot more complex, it would seem to be the way to go. Being stuck with 2MHz exclusion sub bands may be too restrictive.
To mitigate narrowband spurs or CSO/CTB peaks, the use of a 2MHz exclusion may be too wasteful of sub-carriers. All that may be needed for this purpose is to exclude a few sub-carriers.
BTW, is this downstream only or upstream as well? The flexibility is needed more in the upstream than downstream (at least with upstream in the <85MHz region).
From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]<mailto:[mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx]>
Sent: Wednesday, November 28, 2012 7:40 AM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: Re: [802.3_EPOC] Exclusion Sub-band Question
Steve,
Marek,
Thanks for the summaries and thoughts.
As an operator, I think that the second option would be preferable since it provides almost complete configuration flexibility. However, today we are bound to 6 or 8 MHz channel plans with center frequencies following 1 of 3 frequency plans, so method #1 may not be too bad. I think it is probably more about the minimum exclusion zone (which if I understand correctly it would be 2 MHz in method #1 versus 1 sub-carrier in method #2) than about the way to describe it.
But, I wonder about the implementation complexity of method #2.
And, as an alternative to the lack of granularity of method #1, and the extreme granularity of method #2, could there be a method #3 that allows for the exclusion of individual sub-carriers somehow?
Also, could we have vendors' opinions on the implementation complexity of method #2 versus method #1?
Thanks!
Jorge
From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxx]
Sent: Wednesday, November 28, 2012 03:19 AM
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx> <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>>
Subject: Re: [802.3_EPOC] Exclusion Sub-band Question
Steve,
Very good summary of the discussion.
In my mind, both options are very similar, with the only two differences being the granularity of exclusion bands requested (fixed for method #1, arbitrary in method #2) and complexity of configuration (in method #1, we would list bands to be excluded, in method #2, we would list start/stop frequencies for exclusion bands).
If full flexibility is really what we are after, I’d go with method #2, even though it might generate a bit more management traffic to configure CNU. However, it is more future proof and could save us the headache of working with different grids and granularities of channels.
Marek
From: Shellhammer, Steve [mailto:sshellha@xxxxxxxxxxxxxxxx]
Sent: Tuesday, November 27, 2012 23:36
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx<mailto:STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx>
Subject: [802.3_EPOC] Exclusion Sub-band Question
EPoC TF,
On today’s RF Spectrum Ad Hoc call we discussed the Exclusion Sub-band Rules. There are two approaches that we discussed and it was suggested that it would be good to get feedback from the larger group, including the MSOs, on this topic. Here is a description of the two approaches that have been proposed. If you have technical opinions on the advantages/disadvantages of the two approaches or you have a preference for one method, we would like to hear from you.
Method #1
· Exclusion sub-bands are multiples of 2 MHz (e.g. 2, 4, 6, etc.) and are on a 1 MHz grid.
· In this case one could configure 36 MHz exclusion sub-band on the lower channel edge and 36 MHz exclusion sub-band on the upper channel edge and get 120 MHz channel. Then one could include a 2 MHz sub-band within the 120MHz to make room for a cable plant pilot.
Method #2
· Exclusion sub-bands are specified with a start and stop index.
· In this case one could configure a 31 MHz exclusion sub-band on the lower channel edge and a 22.5 MHz exclusion sub-band on the upper channel edge. Then one could also include a 1.75 MHz exclusion sub-band within the channel to make room for a cable plant pilot.
Personal Opinion
· In my opinion, Method #1 is potentially less complex to implement.
· In my opinion, Method #2 provides more flexibility than Method #2
· This seems to be a trade-off between complexity and flexibility
Comments?
Steve
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