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
PGP:
5D0F 93A6 E99D 39D8 B024 0A9B 6361 ACE9 202C
C780
..................................................................................