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

Our January 1999 meeting was hosted by Harris Semiconductor in Orlando, Florida, so that weather conditions had the least impact on the conference and traveling members. Because our host was ready to organize meetings for 3 other groups at the same time and at the same place, this meeting became the summit of wireless standards-making bodies from all over the world, with 240 people attending! The other groups besides the Wireless Local Area Network group, IEEE P802.11, were: It was recommended by a number of attendees that this summit become an annual event.

Work in the 5 GHz band

The Task Group working on the high data-rate extension in the 5 GHz band, project 802.11a, was able to produce a new draft standard that has the support of at least 80 % of the members. (75 % is required, but the IEEE is looking for the highest level of consensus).
The group received a liaison letter from the MMAC/PC Wireless Ethernet working group stating that they adopted the 802.11a draft as well as the Medium Access Control (MAC) of 802.11 for their standards making work.

In a series of joint meetings with the Physical Layer working group of ETSI/BRAN, we made further agreements on the technical details of the PHYs of both groups.. TGa’s chair presented a tutorial to 802.NWEST (broadband access in millimeter wave bands) Study Group to familiarize them with our work and to suggest our physical layer as a candidate for their work. We are looking at a candidate for worldwide standardization!

The draft 802.11a standard is based on Orthogonal Frequency Division Multiplexing (OFDM) to modulate the data. OFDM enables the utilization of wide band signals in an environment where reflected signals would otherwise disable the receiver to recover the data from the received signal.

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.

The editor will implement the agreements which were reached this week into Draft D2.1, which will be sent out for Working Group, Reconfirmation, Letter Ballot.

Regulatory issues in the 5 GHz band

IEEE 802.11 decided to support a letter from ETSI/BRAN to the European Spectrum Engineering group (CEPT WGSE) to ensure that the Radio LAN devices would not harm co-existence with existing users in 650 MHz of the 5 GHz band. IEEE 802.11 also decided to join in sponsorship of a letter prepared by ETSI/BRAN and MMAC-PC to the related Working Party of the ITU-R to support lower restrictions in the 5.15-5.25 GHz band.

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 has reached a technical compromise solution to improve the co-existence and interoperability characteristics between options.

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 could switch back to the 2 and 1 Mbit/s capablities of the DSSS modultaion.

The compromise yielded the Frequency Agility option. In this option the High Rate DSSS signal may hop in its entirely over the 2.45 GHz band in a predetermined manner. This option will ease the migration of Frequency Hopping systems to the High Rate DSSS standard. Another option is to use Packet Binary Convolutional Coding (PBCC).

The editor for this project will make a new draft (D2.last) which will contain the agreements reached this week and send the draft out for a Working Group, Reconfirmation, Ballot. So far the new draft is supported by 81 % of the members.

Regulatory issues in the 2.45 GHz band

The FCC has sent out a Proposed Rule Making (Docket No. 98-42) proposing to allow lighting devices in the 2.45 GHz band which employ magnetrons as sources of RF energy to excite the light emitting material. The part 15 industry has objected towards the unrestricted levels of in-band emissions from those devices. Under the auspices of the FCC, the part 15 industry and lighting industry has come up with a proposed limit. IEEE 802.11 has prepared a draft letter to the FCC with comments on that proposed limit and the definition of the measurement method. The draft letter is up for approval by the IEEE 802 Executive Committee and the IEEE-USA Activity Board for Technology Policies.

Wireless Personal Area Networks

The WG letter ballot on the Project Authorization Request (PAR) and 5 Criteria, as proposed by the Study Group on Wireless Personal Area Networks (WPAN) resulted in an 81 percent approval. The balloted version will be sent to the IEEE 802 community for review and approval at the March 99 meeting. Resolution of comments into new drafts of the PAR and 5 Criteria will be sent out for reconfirmation ballot to be reviewed at the March meeting.

The Study Group has recommended that the work be done in an 802.11 Task Group, provided the rules of 802 provide for the possibility of a difference in MAC. If that would not be true, it recommends to become a Working Group under 802. The 802.11 Working Group did not have any objection to host a tutorial from the Bluetooth industry consortium they would request the chair to do so.

Revision of IEEE Std. 802.11-1997

Although not discussed at the January meeting, the revision of the standard will be submitted to the Standards Board for approval at their March meeting.

Invitation for joining Sponsor Ballot Groups

With both projects 802.11a and 802.11b at over 80 % approval, the chair will ask the IEEE Sponsor Ballot Service to send out invitations to join the related Sponsor Ballot Groups.