[802SEC] Material supporting starting 802.15.3c Sponsor Ballot
Colleagues-
Here is material in advance of our Friday EC meeting supporting the agenda
item requesting approval to start Sponsor Ballot on 15.3c D06 plus MEC
edits. For your convenience, text of the first link is reproduced
below. The remaining two links are for the unedited unsatisfied comment
file and for the Coexistence Assurance Document.
https://mentor.ieee.org/802.15/dcn/09/15-09-0231-00-0000-3c-sponsor-ballot-submission-summary.doc
https://mentor.ieee.org/802.15/dcn/09/15-09-0224-00-003c-unsatisfied-comments-list.xls
https://mentor.ieee.org/802.15/dcn/09/15-09-0022-09-003c-coexistence-assurance.pdf
Letter Ballot Summary:
Total Voters= 168
Initial1st2nd3rd
Yes 99(78.6%)100(78.1%)100(83.3%)112 (84.2%)
No27282221
Abstain6766
· There have been no new NO comments or Voters on the last two recirculations
· A total of 96 comments remain unresolved, 48 rejected, 48 accepted or
accepted in principal
· All comments and responses have been recirculated at least once if not more
· Only 4 out of the 21 NO voters attended any 802.15 meetings during the
prior 2 sessions
· Individual Letters have been sent to each NO voter and 3 responses received
Status of the Draft:
Version D06 was balloted in the third recirculation with no new no votes
and new comments associated with a no vote. Two voters restated their
objections from previous ballots, carrying forward their previous comments
(two comments from one no voter and three from the other no voter).
Draft was submitted for Mandatory Editorial Review in October 2008. Results
were received on February 23, 2009 which required editorial changes to the
draft prior to Sponsor ballot so that it complies with the IEEE 2009 Style
Guide (e.g., correcting the copyright statements, putting in the correct
disclaimer language).
The editor posted a revised version of the draft D06 with these required
editorial changes applied on March 4 and announced its availability to the
working group. Also posted were a comparison showing the changes and a
summary of changes generated by the comparison process.
A summary of the editorial changes is posted at:
<https://mentor.ieee.org/802.15/dcn/09/15-09-0132-00-003c-d06-d07-mandatory-editorial-coordination-changes.ppt>https://mentor.ieee.org/802.15/dcn/09/15-09-0132-00-003c-d06-d07-mandatory-editorial-coordination-changes.ppt
D06 with MEC edits applied would be submitted to Sponsor Ballot.
Status Coexistence Assurance Document:
CA Doc has been reviewed by 802.19 and all suggested comments have been
applied. A copy can found at
<https://mentor.ieee.org/802.15/dcn/09/15-09-0022-09-003c-coexistence-assurance.pdf>https://mentor.ieee.org/802.15/dcn/09/15-09-0022-09-003c-coexistence-assurance.pdf
Comment Resolution Response Summary:
For those who are curious the following summarizes the rejected comments
and reasons for the rejections. The full file can be found at
<https://mentor.ieee.org/802.15/dcn/09/15-09-0224-00-003c-unsatisfied-comments-list.xls>https://mentor.ieee.org/802.15/dcn/09/15-09-0224-00-003c-unsatisfied-comments-list.xls.
The 48 comments fell into 11 categories, which were more philosophical in
character such as "customized for each market segment", "too many versus
normal", "expectation level difference of realization" and such.
Summary by technical category (11):
1. 2 OFDM PHY mode (Number of comments:15, number of no voters: 15)
Essence of comments: It doesn't make sense to have 2 complete OFDM PHY
modes that are so similar.
Reasons of rejection: Different PHYs are a result of demands of different
market segments, which are stated in the usage models. Usage model 1
requires uncompressed video streaming. Due to the nature of uncompressed
video signals a special PHY (AV PHY) is selected to provide high
throughput. Usage model 4 requires a Conference ad hoc system in which all
devices inside the WPAN will have bidirectional, NLOS high speed, low
latency communication which is answered by HSI PHY.. Although AV and HSI
OFDM PHYs share the same modulation technique, their frame design and
approach to communication is very different..
2. Common Mode (Number of comments:13, number of no voters:13)
Essence of comments: In order to promote coexistence it is not sufficient
that a multi-mode PNC transmit beacons in the CR in addition to it's
preferred mode. In order to allow efficient sharing of the spectrum, a
multi-mode PNC must also be capable of allocating channel time to DEVs of
different modes so that piconets of different modes can operate
simultaneously on the same channel. Same-channel multi-mode operation is
important because in many regulatory domains there will be only three
channels available and some DEVs will only be able to operate on one of
these channels (since that is all that some PHYs require).
Reasons of rejection: The SC and HSI PHYs are interoperable since they are
both sending CMS beacons for coexistence and interoperability. For other
cases, the CMS sync frame shall be used for interference mitigation.
Therefore no change is required.
3. Number of PHY mode (Number of comments: 7, number of no voters: 7)
Essence of comments: Three PHYs are two too many. No evidence was presented
that the performance of any of these PHYs is significantly better than any
other so the two additional PHYs simply makes coexistence and
interoperability more difficult for no good reason.
Reasons of rejection: Different PHYs are a result of demands of different
market segments, which are stated in the usage models. For example usage
model 5 is for Kiosk applications. It demands 1.5 Gbps in 1 m range. SC-PHY
can provide such a data rate in such a short range with less complexity
thus lower cost than an OFDM PHY. Whereas usage model 1 requires
uncompressed video streaming. Due to the nature of uncompressed video
signals a special PHY (AV PHY) is selected to provide high
throughput. Usage model 4 requires a Conference ad hoc system in which all
devices inside the WPAN will have bidirectional, NLOS high speed, low
latency communication which is answered by HSI PHY. Mandatory data rates of
all those PHYs are selected according to specific usage models. As with any
other standard we want to give implementers more options than the mandatory
ones, therefore for SC PHY higher data rates are introduced which require
equalization. However it is not appropriate to compare optional features of
SC PHY with mandatory features of any OFDM PHY. Although AV and HSI OFDM
PHYs share the same modulation technique, their frame design and approach
to communication is very different.
4. Remove DAMI/OOK (Number of comments:3, number of no voters: 3)
Essence of comments: DAMI and OOK are inefficient.
Reasons of rejection: The OOK/DAMI modes are optional and designed for low
complexity and low power consumption. The OOK mode can adopt the simplest
envelope detection for low complexity, power consumption and cost
implementation. DAMI is for high data rate applications, and offers low
power consumption and complexity and several implementers are shown interest.
5. Unified aggregation (Number of comments:3 number of no voters: 2)
Essence of comments: Having multiple aggregaion schemes increases
complexity in implementation and makes the spec unecessarily complicated
Reasons of rejection: Different aggregation schemes are result of
contradicting requirements of different applications. Therefore group
created 3 different aggregation schemes.
6. Signal measurements (Number of comments:2, number of no voters: 2)
Essence of comments: At what point shall the ACI and AACI be measured
(e.g., at the antenna connector)?
Reasons of rejection: To address comment on the lack of measurement point,
the following sentence has been added to 12.1.2 RF power measurements in
draft D07:"For DEVs without an antenna connector, the measurements shall be
interpreted as EIRP and any radiated measurements shall be corrected to
compensate for the antenna gain in the implementation."
7. Skewed constellation (Number of comments:1, number of no voters: 1)
Essence of comment: Skewed constellations increase implementation
complexity without providing any benefit over coding schemes for unequal
error protection. Since we already have an effective UEP mode using coding
why should we include this mode?
Reasons of rejection: The skewed constellation as an option provides
different advantages as compared with coding schemes.
8. Non-PHY specific MAC (Number of comments:1, number of no voters: 1)
Essence of comment: The spec draft defines the MAC features dependent on
the PHY. It makes each MAC PHY dependent, and supporting separate set of
features. As a result there is no MAC compatibility and the spec
effectively becomes set of few separate specs. Such an approach complicates
the spec and more important significantly increases complexity of
implementation, verification, and certification. There is no limitation
seen to unify the MAC features.
Reasons of rejection: There have been efforts trying to unify the MAC
functionality as much as possible. In D07, sections 7, 8 and 13 are common
to all the PHYs. There are some features specified for particular PHYs,
such as AV aggregation. This is a common and reasonable approach which can
be also seen in other 802 standards such as 802.16.
9. AV PHY SIFS time (Number of comments:1, number of no voters: 1)
Essence of comment: A SIFS time of 2us corresponds to over 5000 samples at
the nominal sampling rate. Such a large SIFS adds a very high per-frame
overhead and results in very low throughput for applications that require
transmission of short frames (such as wireless equivalents of wired
peripheral buses). Note that the SIFS duration for the 802.11 OFDM PHY is
only 200-320 samples. Achieving such low turn-around times is technically
challenging but will be necessary if the specification is to support
applications other than simple streaming and file transfer.
Reasons of rejection: The SC and HSI PHYs are interoperable since they are
both sending CMS beacons for coexistence and interoperability. For other
cases, the CMS sync frame shall be use for interference
mitigation. Therefore no change is required.
10. Mandatory beam forming (Number of comments:1, number of no voters: 1)
Essence of comment: 60GHz WPAN has to do beam forming in order to fulfil
the link budget. Why is beam forming optional? - Specify a mandatory beam
forming scheme.
Reasons of rejection: Very simple, low cost devices will use only a
directional antenna and will rely on the user to point the device in the
direction of the other device.
11. SC PHY Preamble (Number of comments:1, number of no voters: 1)
Essence of comment: Two different CES lengths seems awkward, and the number
of header rates can also be reduced. SFD2 can also be used for deliminator
to gain frame timing reliability.
Reasons of rejection: In SCPHY, long CES and short CES are kept to increase
performance or efficiency if necessary.
Bob Heile, Ph.D
Chairman, ZigBee Alliance
Chair, IEEE 802.15 Working Group on Wireless Personal Area Networks
11 Robert Toner Blvd
Suite 5-301
North Attleboro, MA 02763 USA
Mobile: +1-781-929-4832
email: bheile@ieee.org
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