RE: stds-80220-requirements: Frame Error Rate Requirement
Hello, All
Jim's text "The Air
Interface (PHY+MAC) shall include mechanisms to allow negotiating a range of
latency vs. data loss/error rates subject to application types." seems close to
ideal. The only possible change could be "control"
instead of "negotiation" (which is a particular
type of control; e.g. configuration is another type).
Argumentation for having DiffServ [or another
specific mechanism of QoS control] seems not sufficient.
We have to differentiate between "IP-centric"
and "IP-aware". There seems to be a wide consensus about
"IP-centric"
meaning MAC/PHY optimized for transferring traffic
with characteristics similar to those we used
to see in IP traffic [bursty nature, nIPP models,
... etc.]. "IP-awareness" would mean that virtually every 802.20
device
should operate as IP host with functions like DiffServ [or IntServ or RSVP
or MPLS, ... endless list]. I don't think,
IP-awarness would gain serious support - business
of IEEE 802 wireless is MAC/PHY. We may learn from another groups and
concentrate on MAC/PHY with possible addition of classification
of non-802.20 data units (Ethernet packets, IP datagrams etc.). Classifier looks
at certain fields of IP datagram, for example, at TOS field,
and decides whether certain MAC/PHY rule [e.g. lower delay with less
restrictions on FER] is
applicable to the datagram.
Such approach does not preclude from further
development of complimentary standard that may point e.g. to
DiffServ
as a recommended QoS control protocol; but such a
standard should be separated from MAC/PHY
specifications.
Example of complimentary
standard: PacketCable [for DOCSIS MAC/PHY]
Vladimir
I
agree that the MAC/PHY must be able to handle various application requirements
in terms of data loss/error rates etc in a flexible manner. However, given the
IP-centric nature of system, it might be better for application QoS
requirements such as these to be framed in a more unified and
comprehensive manner through use of the diffserv architecture (for which
there seems to be broad support in the group).
Samir
At
10:30 PM 7/30/2003 -0400, Kapoor Samir wrote:
Just to add to Mike's, and
others before, point about the difficulty in
specifying a particular
FER threshold. In addition to different applications
having different
target FER vs latency tradeoffs, another issue is that the
extent of
uncertainty in channel quality measurements (e.g. depending on the
SNR
regime, rate of channel variation etc) can significantly impact
the
transmitter's selection of appropriate transmission (e.g. coding
and
modulation) parameters and corresponding FER targets under
different
conditions. Consequently, it is probably best to not mandate
a single FER
threshold.
Samir, Michael, Joseph, and
others...
Samir makes a good point here about the fact that different
applications require different FER vs Latency tradeoffs. There are
many different types of traffic we're attempting to serve with this
technology. We've learned this in the CDMA data world too, and as a
result, our radio link protocols are now designed to support negotiating a
range of error/data loss characteristics from that of the raw airlink
(for apps that can support frame loss but not much latency) through that
roughly equivalent to a wireline (for the purposes of TCP retransmission
performance).
Maybe my original comment (from an e-mail 7/16/2003
which wasn't addressed by the group) may help. PThe comment suggests a
requirement to support a range of error vs. latency tradeoffs. These
could be negotiable upon channel setup, if information about the traffic
type is available. Suggest some text such as this:
The Air Interface (PHY+MAC) shall include mechanisms to allow
negotiating a range of latency vs. data loss/error rates subject to
application types.
Best Regards,
Jim
Samir
-----Original Message-----
From: Michael Youssefmir [mailto:mike@arraycomm.com]
Sent: Wednesday, July
30, 2003 8:14 PM
To: Joseph Cleveland
Cc: 'Dorenbosch
Jheroen-FJD007'; stds-80220-requirements@ieee.org;
Michael
Youssefmir
Subject: Re: stds-80220-requirements: Frame Error Rate
Requirement
Hi Joseph,
I see that this
discussion is moving into specific design requirements
such as frame
length instead of addressing functional requirements.
1) An FER
requirement seems to be irrelevant absent the specifics of
the design
and would have different performance implications for
different
designs. As Jheroen pointed out a specific requirement
such as 1%
will bias the requirement to shorter frames, and, as your
response
indicates we rapidly have to go down the path of specifying
frame
lengths to make the requirement have meaning. I think we are
far better
off having the requirements document focus on high level
functional
requirements and not specify specifics such as frame length.
2) As
Jinweon pointed out tuning of FERs has performance
implications in
trading off throughput and latency. For latency
insensitive data, the
"FER can be less strict in order to maximize
throughput over the air",
and for other data, the "FER needs to be
tightly controlled below a
certain threshold". Again I therefore
think it is premature to define a
specific FER.
For these reasons, I continue to believe that we
should remove
the specific FER value and therefore delete the
sentence:
"The frame error rate shall be less than 1 percent, with
95% confidence,
after channel decoding and before any link-level ARQ,
measured under
conditions specified in Section
xx."
Mike
ArrayComm, Inc.
On Tue, Jul 29, 2003 at
04:58:15PM -0500, Joseph Cleveland wrote:
> Hi All -- Yes, we need a
frame length. This is why I asked what MAC layer
> "RLP" we
intend to use.
>
> Joseph Cleveland
>
>
-----Original Message-----
> From: Dorenbosch Jheroen-FJD007 [mailto:J.Dorenbosch@motorola.com]
> Sent:
Tuesday, July 29, 2003 3:31 PM
> To:
stds-80220-requirements@ieee.org
> Subject: RE:
stds-80220-requirements: Frame Error Rate Requirement
>
>
> We seem to be converging.
>
> However, will
it not be hard to specify a maximum error rate for a frame
> unless
we have an idea of the length of the frame or of the number
of
useful
> bits in a frame? A generic requirement could bias
towards short frames.
>
>
> Jheroen Dorenbosch
>
> -----Original Message-----
> From: Joseph
Cleveland [mailto:JClevela@sta.samsung.com]
> Sent:
Tuesday, July 29, 2003 1:40 PM
> To:
stds-80220-requirements@ieee.org
> Subject: stds-80220-requirements:
FW: Frame Error Rate Requirement, 4.1.10
>
>
>
> Hi All: It seems that some are referring to a previous
re-write of
4.1.10,
> Frame Error Rate. Several of the
items noted were already addressed in
the
> latest version sent
on 7/24, which is attached below. Please refer to the
>
content in v0.2.1 so there is not wasted discussion.
>
>
Regards
>
> Joseph Cleveland
>
>
-----Original Message-----
> From: Joseph
Cleveland
> Sent: Thursday, July 24, 2003 12:44
PM
> To: stds-80220-requirements@ieee.org
> Subject: Frame Error
Rate Requirement, 4.1.10
>
> Hi All,
>
> Here
is a revision to the wording on section 4.1.10 based on feedback
from
> many of you. Thanks for the comments.
> <<frame_error_v0.2.1.rtf>>
>
Joseph Cleveland
> Director, Systems & Standards
>
Wireless Systems Lab
> Samsung Telecommunications America
>
Richardson, TX 75081
> (O) 972-761-7981 (M)
214-336-8446 (F) 972-761-7909
>
..................................................................................
James
D. Tomcik
QUALCOMM,
Incorporated
(858)
658-3231 (Voice)
(619)
890-9537 (Cellular)
From:
San Diego, CA
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