Re: [802.3_EPOC] Study Group Questions
Hi Matt,
It is a long-standing rules in 802.3 that projects develop a single solution
for a single problem. Unless it can be demonstrated that there are two
separate problems, each one needing a unique PHY solution, I'd think we are
bound to converge here onto one solution only.
Note also that at the SG phase, we do not develop solutions. That is the job
of the Task Force in the near future. SG discusses objectives for the future
Task Force, and we should be concerned only about them at this time.
Marek
-----Original Message-----
From: Matthew Schmitt [mailto:m.schmitt@xxxxxxxxxxxxx]
Sent: 03 January 2012 22:46
To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_EPOC] Study Group Questions
Alex,
In response to your comment below to me...
I'm not sure I agree that a TDD system inherently provides more spectral
flexibility than an FDD system in a passive coax environment. Depending on
the PHY layer, you can do quite a bit of steering regardless of FDD vs.
TDD. I will agree that a TDD solution can provide advantages in terms of
the relative allocation of bandwidth to upstream vs. downstream operation,
although only with a MAC designed to support such features.
That said, I'm more than open to being proven wrong, and so I will
definitely look forward to your presentation to highlight why you believe
TDD had advantages over FDD.
BTW, I also tend to agree with others on this thread that it's MUCH
preferred if we can develop a single solution. Without that, you end up
with a fragmented market, and it's much harder to achieve the same economies
of scale that you could have with a single, unified solution.
If it's simply not possible to come up with a single unified solution, so be
it; but I think that should be our goal if at all possible.
Thanks.
Matt
On 12/15/11 7:48 PM, "Liu, Alex" <alexliu@xxxxxxxxxxxxxxxx> wrote:
>Ed,
>
>Let me reiterate some of the finer points of my previous missive: (1)
>TDD systems have a wide footprint in China in part due to their
>spectral convenience, (2) TDD should be an optional profile in addition
>to and not in place of FDD. I do believe that market enthusiasm for,
>and acceptance of, this standard and its ensuing products should be our
>guiding principle, and not doctrinal orthodoxy within a standards
>framework. If things weren't so, Ethernet would have never abandoned
>CSMA/CD for first-mile applications.
>
>More specifically, it is clear that an FDD RF system that directly maps
>to the dedicated wavelengths in fiber and thus the EPON protocol is
>most appropriate for the N. American MSO environment. I would like to
>raise the possibility that this is not necessarily true for China.
>Passive cable plant coupled with haphazard spectrum planning makes for
>an inviting TDD target. There are then the orthodoxies emanating from
>the Chinese side. If we are serious about targeting the China market, I
>suggest we consider SARFT's input.
>
>@Matt: TDD's ability to operate in unpaired spectrum makes "lively"
>spectrum plans possible in China. Perhaps this is improperly termed
>"coexistence with" and is better called "steering around" existing TV
>and data systems. This additional degree of freedom may perhaps be
>attractive to N. American operators as well.
>
>@Mark: we *are* working toward a single standard. Transparent EPON
>protocol operation over coax is the goal and FDD RF operation should be
>the mandatory supported mode. Employing the modern PHY proposals being
>developed in an optional TDD mode should not detract from this stated
>goal. LTE offers an instructive precedent.
>
>Alex
>
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