Summary report of the May 1999 meeting of IEEE P802.11

Our May 1999 meeting was held in Chiba, Japan, hosted jointly by NTT, NEC and Clarion. Fifty two attendees were registered, about four attending a management group of 802.15 to set-up the working group. Everyone enjoyed the perfectly organised meeting! A special thanks and compliment to Hitoshi Takanashi and Masataka Iizuka and the many persons that helped them!

ARIB, MMAC and the Tokyo IEEE section had taken the opportunity of our presence to organize a Wireless LAN Seminar, including an exhibition. The event drew some 500 people! On Friday the exhibition included 13 exhibiters, ranging from the current 802.11 devices to various high data rate devices in the 2.4 GHz band and prototypes for high data rate equipment in the 5, 6 and 19 GHz bands.

On the Friday afternoon, a half-day Wireless LAN seminar was held after the closing plenary meeting of 802.11. 5 Papers were presented by respectively MMAC, 802.11 chair, 802.11a chair, 802.11b chair and the interim 802.15 chair.

Work in the 5 GHz band

Task Group a working on the high data-rate PHY in the 5 GHz band, project 802.11a, processed comments from it's Sponsor Ballot. The meeting actually started before the ballot closed, so comments continued to flow in as the work progressed. 86 people responded to the ballot, of which 5 submitted "no" votes. After processing the comments, only 2 "no" votes remained (97% support!), and we hope to resolve those at the teleconference scheduled to end of May. The editor already implemented the resolved comments into draft D5.3, after the teleconference D5.5 will be produced, and in the begining of June a Reconfirmation Sponsor Ballot will be issued. The comments from this ballot will be processed in the July plenary meeting in Montreal.

Representatives from BRAN and from MMAC contributed comments and participated in discussions. The structure of the packet preamble and its parameters were a hot discussion item. The changes to the 802.11a Draft were relatively minor. At the end of the meeting a liaison statement was issued to BRAN and MMAC-PC, acknowledging their contributions and updating them on the March and May changes in the draft standard.
The draft 802.11a standard 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 54Mbit/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.

From the seminar:

Currently the 5 GHz band is open to unlicensed devides only in USA. Mr. Hashimoto (NTT) updated, among other issues, on the intent to open the 5 GHz band in Japan in the begining of 2000. Naftali Chayat, TGa chair, presented an overview of the 802.11a standard and the collaboration with MMAC-PC and with BRAN. In particular, MMAC-PC Wireless Ethernet working group intends to adopt the 802.11a standard, while the WATM groop of MMAC-PC and ETSI BRAN agreed with 802.11a on most modulation parameters. In Europe currently the only available band in 5 GHz is allocated to the HIPERLAN project. Based on the broad level of agreement and collaboration between 802.11a and BRAN, 802.11a issued a liaison statement to ETSI BRAN asking it to support the inclusion of 802.11 with 802.11a PHY in its HIPERLAN family of standards. If ETSI will support 802.11a in Europe, the 5 GHz high speed wireless LANs will enjoy same worldwide availability that 2.4 GHz devices enjoy today!

Work in the 2.45 GHz band

The Task Group working on the extension of the 1 and 2 Mbit/s data rates in the 2.45 GHz band with 5.5 and 11 Mbit/s addressed the comments received during first round of the Sponsor Ballot. The Task group worked on all of the available comments. The Ballot though was not closed at the time of the Tokyo meeting. Therefore, the interim meeting will officially adjourn on May 28 when there is a teleconference scheduled to resolve any additional comments received.

As of May 7, 1999  92% of the ballots had been submitted . Out of these ballots the approval percentage is 89% with 8% of the sponsor ballot members abstaining. The editor already produced Draft 5.3. In June, after the decision of the May 28, 1999 meeting, the final outcome will be posted and submitted to Sponsor Recirculation Ballot.

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 capablities of the DSSS modultaion.

Work on update of Regulatory domains

Task Group d began operation at the May meeting in Chiba, Japan, in anticipation of the approval of its PAR by NeSCom in June.  The task group selected Bob O’Hara of Informed Technology as its chairperson and Harry Worstell of AT&T Labs as its vice chairperson.

The task group discussed its proposed work and believes that “super domains” can be defined that will cover several political/geographic domains.  The desire of the people attending this meeting is to ultimately have only a single regulatory domain that will allow operation of 802.11 equipment on every square metre of planet Earth.  To achieve this goal, the task group solicits submissions for the July meeting from interested individuals, proposing new regulatory domains and methods for achieving the aggregation into super domains.

The May 1999 session is still in progress pending the May 28, 1999 part of the meeting to close the final inputs to the ballots.