Date: April 18, 2007 12:10:15 PM MDT
Subject: [802SEC] +++10 Day EC Email Ballot (Closes no later than 29 April 2007)+++ Motion to approve the formation of the 802.11 Video Transport Stream (VTS) Study Group
Dear EC Members,
The 802 EC Chair has delegated me to conduct this EC ballot on his behalf.
This is a 10 day email ballot to make a determination on the withdrawn
motion which was deferred to an 802 EC email ballot, that was submitted to
the Closing Orlando March 2007 802 EC meeting:
Motion: "To approve formation of an IEEE 802.11 Study Group to examine
issues related to delivery of Video Transport Streams (VTS) over IEEE
P802.11, with the intent to create a PAR and Five criteria to form a new
Task Group. The proposed PAR and 5C would be reviewed by the 802.1 Audio
Video Bridging Task Group (802.1AVB TG), and in addition both the 802.1AVB
TG and 802.11 VTS SG (and eventually the 802.11 TG, if formed) will meet
jointly at IEEE 802 plenary meetings, unless mutually agreed not to".
Moved: Stuart J. Kerry
Seconded: Tony Jeffree
This ballot opens 11:59 PM ET Wednesday 18th, 2007 and closes when all
voting EC members have cast a ballot but no later than 11:59 PM ET Sunday
April 29th, 2007 if enough ballots have been cast for a decision to be made
(more than 9 approves or disapproves).
Executive Summary:
The proposed 802.11 Video Transport Stream (VTS) Study Group will focus on
enhancements within the 802.11 MAC/PHY layers to improve video streaming
performance over 802.11 links. The problem space is constrained to be
limited to issues unique to 802.11 and nothing more.
The 802.11 VTS SG will collaborate with 802.1AVB TG to ascertain that 802.11
specifications include support for all mechanisms specified in 802.1AVB. If
there are no mechanisms within 802.11 to support 802.1AVB, the 802.11 VTS SG
will work jointly with 802.1AVB TG to specify the required mechanisms. This
strategy is decided based on discussions with Michael Johas Teener (802.1AVB
TG Chair) and Ganesh Venkatesan (Proposed Chair of the 802.11 VTS SG, if
approved), as well as the two WG Chairs.
If the 802.11 VTS SG formation is approved by the EC, the tentative schedule
for 802.11 VTS SG in May interim meeting in Montreal includes a presentation
on 802.1AVB and 802.1AVB Transport Protocol followed by a discussion how
802.11 fits into this specification. These meetings are open to all 802
members.
Approved in 802.11 WG:
. 802.11 WNG SC - Results: 59-3-11
. WG - Results: 76-1-25
Details:
802.11 VTS SG is focused on enhancements within the 802.11 MAC/PHY layers to
improve the performance of video streams sent over 802.11 links. This is the
main focus of the 802.11 VTS SG and is expected that the SG will spend 80%
of its time in this activity. Some of the areas for study are (not in any
specific order, not a complete list). Some of these topics are not fully
explored yet:
1. Enhancements to 802.11e mechanisms to render them effective for
transport streams (not all bits are equal
2. QoS Management mechanisms (permits QoS control from higher layers)
3. Optimizations to make medium access more deterministic
4. Forward Error Correction techniques that are effective for 802.11
(specifically low reliability of the medium)
5. Resiliency mechanisms to mitigate interference
6. Heuristics for retransmission, packet drop, etc
7. Channel dynamics estimation and adaptation techniques
In addition (if there are currently no known mechanisms in 802.11) the VTS
SG, in order to guarantee that the wired and wireless sub-systems can
co-exist, will also work on the following items listed below. It is
anticipated that the items in this list will involve some level of joint
activity between 802.1AVB TG and 802.11 VTS SG. About 20% of the 802.11 VTS
SG activity is expected here. Please note that the items listed below will
be in 802.11 (if needed) but will be performed jointly with the experts from
802.1AVB TG.
. Mechanisms to support those specified by 802.1 Qat (stream
reservation protocol - bandwidth, latency, Admission Control and Time
Synchronization) and 802.1Qav (forwarding and queuing of time-sensitive
streams). Note that support for 802.1AS is already included in 802.11v.
. Mechanisms to support 802.1Qas (time synchronization).
. Any additional mechanisms that are specified in 802.1AVB requiring
additional support in 802.11.
A liaison will be established between 802.1AVB TG and 802.11 VTS SG. The
liaison will ascertain 802.1 AVB mechanisms and optimizations in 802.11 for
video streaming are compatible and they work together to improve streaming
performance. This will be a 2-way communication - advancements in 802.1AVB
will be made known to the 802.11 VTS SG members and advancements made in the
SG made known to 802.1AVB TG members.
. The documents generated by the two groups may be reviewed by each
other (on a case by case basis),
. There may be presentations from one group to the other to provide
rationale/motivation for an approach/solution and
. Members from each group will attend meetings of the other when
possible.
Regards,
/ Stuart
_______________________________
Stuart J. Kerry
Chair, IEEE 802.11 WLANs WG
c/o: NXP Semiconductors,
1109 McKay Drive, M/S 48A SJ,
San Jose, CA 95131-1706,
United States of America.
+1 (408) 474-7356 - Phone
+1 (408) 474-5343 - Fax
+1 (408) 348-3171 - Cell
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