Summary report of the November 1999 meeting of
IEEE 802.11
Our November 1999 meeting was held at the Hyatt Regency Kauai, Hawaii,
organised by our Executive Committee Executive Secretary, Buzz Rigsbee
and his team of meeting organizers from Face-to-Face Meetings. The members
of 802.11 complimented the organizers with the excellent meeting facilities,
excellent social event and the setting of the island.
Meeting schedule
The next interim meeting will be held in Tel-Aviv, Israel, January 10-14,
2000. If members or observers expect delays from arrival and departure
safety interviews, the host has offered to provide invitation letters.
The deadline for hotel reservations is November 25, 1999.
Work in the 5 GHz band
"Task Group a" has finished its work. Chair Naftali Chayat and Editor Hitoshi
Takanshi discussed the final edits with our IEEE editor Janet Rutigliano.
Janet can now complete the publication.
Through the BSI, the approved draft version of IEEE 802.11a has been
forwarded to the appropriate persons to start a so-called Fast Track procedure
for International Standard.
IEEE Standard 802.11a-1999 is based on Orthogonal Frequency Division
Multiplexing (OFDM) to modulate the data. The main benefit OFDM modulation
is its robustness to multipath echoes, which are typical to the indoor
and mobile
environments. Each OFDM symbol is composed of 52 subcarriers, of which
48 carry data and 4 subcarriers serve as
phase reference pilots. The specifications of the Physical Layer encompass
data rates from 6 Mbit/s up to 54 Mbit/s, with
20 MHz spacing between adjacent channels. All implementations are required
to support 6, 12 and 24 Mbit/s. Optional
extensions are for 9, 18, 36, 48 and 54 Mbit/s. The range of data rates
is provided to match the wide range of radio
channel characteristics in both indoor and outdoor environments. The
multirate mechanism of the MAC protocol ensures
that all devices communicate with each other at the best data rate
in the present channel.
Work in the 2.45 GHz band
"Task Group b" working has finished its task too. However, the instructions
for the update of Annex D to make a new Management Information Base (MIB),
need to be updated. IEEE 802.11b will be published shortly with a note
in Annex D referring to the ongoing work and with a reference to our web
site to keep users informed about the status.
Bob O'Hara has started the work and the Executive Committee approved
a PAR for an 802.11b Corrigendum. The Chair of 802.11 will start a Working
Group Ballot as soon as the MIB experts have reviewed Bob's proposal.
In IEEE Std 802.11b, the modulation used is Complementary Code Keying
(CCK). CCK is the mandatory mode of operation for the (draft) standard,
it is derived from the Direct Sequence Spread Spectrum (DSSS) technology.
The multirate mechanism of the Medium Access Control (MAC) warrants that
the 11 Mbit/s operation can switch back to 5.5 Mbit/s if the radio channel
is below the required value because of the distance between the stations
or because of interference. Stations that are even further away could switch
back to the 2 and 1 Mbit/s capabilities of the DSSS modulation.
Work on update of Regulatory domains
Task Group d, chaired by Bob O'Hara,
met this week in Kauai to create a draft of the standard for regulatory
extensions to 802.11. Two submissions were made to the task group
that provided a great deal of material toward the creation of the draft.
As a result, the task group was able to create a substantially complete
draft of the standard for regulatory extensions. The draft specifies
extensions to MAC management operation and to the MAC management protocol.
It also defines additional information elements. Work remains to
be done in the areas of changes to the MAC state machines and changes to
the Protocol Implementation Conformance Statement (PICS). The draft
was forwarded to the 802.11 working group, to conduct a letter ballot for
the purpose of obtaining concrete, written feedback on the content of the
draft.
New
work on Enhancements of 802.11
The study group under the chairmanship
of John Fakatselis produced 2 PAR and 5 Criteria documents for enhancements
to the 802.11 standard. The documents are ready to be sent to the Executive
Committee for approval at their March 2000 meeting.
The first project authorization
request proposes to enhance the 802.11 Medium Access Control (MAC) to improve
and manage Quality of Service, to provide classes of service, and to enhance
security and authentication mechanisms. The work done under this PAR will
also consider efficiency enhancements in the areas of the Distributed Coordination
Function (DCF) and Point Coordination Function (PCF).
The second project authorization
request is to develop recommended practices for an Inter-Access Point Protocol
(IAPP) which provides the necessary capabilities to achieve multi-vendor
Access Point interoperability across a Distribution System supporting IEEE
P802.11 Wireless LAN Links. This IAPP will be developed for the following
environment(s):
1) A Distribution System consisting
of IEEE 802 LAN components supporting an IETF IP environment.
2) Others as deemed appropriate
Regulatory activities
The group prepared three documents:
-
Reply-Comments in response to the FCC Notice of Proposed Rule Making,
ET Docket No. 99-231, Proposal to change the rules of Spread Spectrum.
-
Response to the UK-Radio Communications Agency
-
A letter to be submitted by Boeing, endorsed by 802.11, to encourage the
harmonization and protection of the 5 GHz bands for our devices.
The first one was approved, the second and third will be reviewed by e-mail.