Summary of
the 802.11 Task Groups
|
Name |
Status |
Layer Type |
Summary |
|
802.11a |
Approved |
Physical |
High data rate extension 6~54Mbps
|
|
802.11b |
Approved |
Physical |
High data rate extension of 802.11 DSSS. 5.5/11Mbps
|
|
802.11b-cor1 |
New Standard Proj. |
Physical |
Corrects errors in the MIB (Medical Information Bus)
definition in 802.11b |
|
802.11c |
Approved |
Physical |
Specifications for WLAN specific bridge interfaces to MAC
layers |
|
802.11d |
New Standard Proj. |
Physical |
Regulatory domain update |
|
802.11e |
New Standard Proj. |
MAC* |
Security and QoS |
|
802.11f |
New Standard Proj. |
MAC |
Inter Access Point Protocol
|
|
802.11g |
New Standard Proj. |
Physical |
20Mbps+ extension to 802.11b
|
|
802.11h |
New Standard Proj. |
Physical |
Spectrum managed 802.11a
|
*Medum
Access Control. Note: Physical layer standards specify technical hardware
requirements. MAC layer standards specify interfaces, especially
software.
Of the listed standards, 802.11a/b/g/h are the most
important to WLAN hardware. A and B are already approved standards, while
H and G are proposed improvement to them.
A:
Based on the 5GHz Orthogonal Frequency Division Multiplexing
(OFDM), 802.11a is a standard for WLANs that boasts speeds comparable to
wired networks. Cisco got an edge on the competition by acquiring Radiata
Systems of Austrailia, but is facing patent-infringement challenges from
Wi-LAN of Canada, which developed OFDM. Should the legal conflicts be
resolved, 802.11a should be the leading contender to replace wired
broadband within the next decade.
H:
802.11h is a new standard initiative in the works to improve
regulatory acceptance of 802.11a 5GHz products by improving spectrum and
transmit power management (there are official limits on transmitting power
for the 5GHz unlicensed band just as there is one in the 2.4GHz
band).
B:
An extension of the 802.11 Direct Sequence Spread Spectrum (DSSS)
standard, 802.11b operates at 5.5/11Mbps. It is by far the most popular
and widely accepted standard in the WLAN market. Intersil controls nearly
80% of the 802.11b chip market. Agere Systems, a recent Lucent spin-off,
controls the other 20%. Major WLAN players have invested in this standard.
Cisco, Lucent, and BreezeCOM, among many others boast a line of 802.11b
products, including NICs, Access Points, and network bridges. Thanks to
rapidly dropping prices, 802.11b is quickly gaining widespread popularity
and is expected to generate more than $1.1 billion in revenues for the
industry this year.
G:
802.11g is a higher speed extension to 802.11b. By enhancing
performance, 802.11g will attempt to broaden the scope of possible
applications for 802.11b compatible networks. The IEEE has not yet
specified which transmission technology will be used, although a decision
should be made by the end of March 2001. There are three different
techniques in the running of which OFDM and PBCC (Packet Binary
Convolutional Coding) seem to be the clear front-runners. PBCC, developed
by Alantro (recently acquired by Texas Instruments), is a royalty-free
technology that is fully backward compatible with 802.11b while providing
improvements in power conservation and transmission range. Intersil, the
biggest WLAN chipmaker, is backing OFDM, developed by Wi-LAN. The proposed
OFDM solution is not fully compatible with existing 802.11b networks and
is a more costly extension than PBCC. PBCC can be implemented using
existing 802.11b silicon manufacturing equipment, which makes it
cost-competitive. However, Intersil¡¯s dominant position in the industry
may have influence on the outcome. The IEEE voted heavily in favor of PBCC
in an earlier meeting last fall.
802.11c and
802.11f are network interoperability standards that will hopefully
help WLAN systems gain more widespread use. 802.11c will specify
interfaces by which wireless bridges communicate with the rest of the
network. 802.11f will attempt to lay down the standards necessarily for
interoperability between APs made by different vendors by specifying how
AP MACs communicate with the distribution system (DS, or the entire
network).
The purpose of 802.11e is to
enhance 802.11 MAC to meet security and Quality of Service (QoS)
requirements to support various applications. 802.11e aims to enhance the
efficiency of data transmission, especially multimedia content.
Applications like Sony¡¯s PCF television should become more readily
implemented once this standard takes hold.
802.11b-cor1 will
correct some deficiencies in the 802.11b standard definition of Medical
Information Bus (MIB) so that existing MIBs will be interoperable with
802.11b WLANs. This should accelerate the WLAN penetration in the medical
services market.
802.11d aims to
add more requirements and definitions to the existing 802.11 standard so
that it will be possible for 802.11 WLAN equipment to operate in all
countries.
Official
IEEE Descriptions
--------------------------------------------------------------------------------
Designation: 802.11a-1999
Project scope: To
develop a Higher Speed PHY for use in fixed, moving or portable Wireless
Local Area Networks. The PHY will be used in conjunction with the 802.11
Medium Access Control (MAC). The 802.11 MAC will be reviewed to assure its
capability to operate at the speeds targeted.
Project purpose: To create
a higher speed wireless access technology suitable for data, voice and
image information services.
--------------------------------------------------------------------------------
Designation: 802.11b-1999
Project scope: The
project will evaluate the possibility orf taking advantage of the
provisions for rate expansion that are in place on the current standard
PHYs. The 802.11 MAC defines a mechanism for operation of stastions
supporting different data rates in the same area. The current 802.11
standard already defines the basic rages of 1Mbit/s and 2 Mbit/s for both
Frequency Hopping *FH) and Direct Sequence (DS) PHYs. The two rates are
supported by having same header for both rates with length and rate
information passed in the header at the lowest ("basic") rate; then the
body of the packet is transmitted at the rate chosen and with the
corresponding modulation method. The header structure of the two PHYs
already supports passing rate information up to 4.5 Mbit/s (in 0.5 Mbit/s
increments) for FH and up to 25.5 Mbit/s (in 0.1 Mbit/s increments) for
DS. The proposed PAR targets further developing the provisions for
enhanced data rate capability of 802.11 networks. The 802.11 MAC
incorporates already the interpretation of this information and the
computation of expected packet duration even if the specific station does
not support the rate at which the packet was sent. The 802.11 MAC is
compatible and will accommodate the higher PHY rates.
Project purpose: To extend
the performance and the range of applications of the 802.11 compatible
networks in the 2.4 GHz band by increasing the data rate achieveable by
such devices. This technology will be beneficial for improved access to
fixed network LAN and internetwork infrastructure (including access to
other wireless LANs) via a network of access points, as well as creation
of high performance ad-hoc networks. The purpose of 802.11a is also for
higher data rates, however, that project is for operation in the 5 GHz
band, whereas this project is for operation in the 2.4 GHz
band.
--------------------------------------------------------------------------------
Designation: P802.11b-1999/Cor 1
Project scope: The scope
of this project is to correct deficiencies in the MIB definition of
802.11b.
Project purpose: As the
MIB is currently defined in 802.11b, it is not possible to compile an
interoperable MIB. This project will correct the deficiencies in the
MIB.
--------------------------------------------------------------------------------
Designation: 802.11c-1998
Project scope: To add a
subclause under 2.5 Support of the Internal Sublayer Service by specific
MAC Procedures to cover bridge operation with IEEE 802.11 MACs. This
supplement to IS 10038 (802.1D) will be developed by the 802.11 Working
Group in cooperation with the 802.1 Working Group.
Project purpose: To
provide the required 802.11 specific information to the IS 10038 (802.1D)
standard.
--------------------------------------------------------------------------------
Designation: P802.11d
Project scope: This
supplement will define the physical layer requirements (channelization,
hopping patterns, new values for current MIB attributes, and other
requirements to extend the operation of 802.11 WLANs to new regulatory
domains (countries).
Project purpose: The
current 802.11 standard defines operation in only a few regulatory domains
(countries). This supplement will add the requirements and definitions
necessary to allow 802.11 WLAN equipment to operate in markets not served
by the current standard.
--------------------------------------------------------------------------------
Designation: P802.11e
Project scope: Enhance
the 802.11 Medium Access Control (MAC) to improve and manage Quality of
Service, provide classes of service, and enhanced security and
authentication mechanisms. Consider efficiency enhancements in the areas
of the Distributed Coordination Function (DCF) and Point Coordination
Function (PCF).
Project purpose: To
enhance the current 802.11 MAC to expand support for LAN applications with
Quality of Service requirements. Provide improvements in security, and in
the capabilities and efficiency of the protocol. These enhancements, in
combination with recent improvements in PHY capabilities from 802.11a and
802.11b, will increase overall system performance, and expand the
application space for 802.11. Example applications include transport of
voice, audio and video over 802.11 wireless networks, video conferencing,
media stream distribution, enhaced security applications, and mobile and
nomadic access applications.
--------------------------------------------------------------------------------
Designation: P802.11f
Project scope: 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. This Recommended Practice Document shall support the IEEE
P802.11 standard revision(s).
Project purpose: IEEE
P802.11 specifies the MAC and PHY layers of a Wireless LAN system and
includes the basic architecture of such systems, including the concepts of
Access Points and Distribution Systems. Implementation of these concepts
where purposely not defined by P802.11 because there are many ways to
create a Wireless LAN system. Additionally many of the possible
implementation approaches involve concepts from higher network layers.
While this leaves great flexibility in Distributions System and Access
Point functional design, the associated cost is that physical Access Point
devices from different vendors are unlikely to inter-operate across a
Distribution System due to the different approaches taken to Distribution
System design. As P802.11 based systems have grown in popularity, this
limitation has become an impediment to WLAN market growth. At the same
time it has become clear that there are a small number of Distribution
System environments that comprise the bulk of the commercial WLAN system
installations. This project proposes to specify the necessary information
that needs to be exchanged between Access Points to support the P802.11 DS
functions. The information exchanges required will be specified for, one
or more distribution Systems; in a manner sufficient to enable the
implementation of Distribution Systems containing Access Points from
different vendors which adhere to the recommended
practices.
--------------------------------------------------------------------------------
Designation: P802.11g
Project scope: To
develop a higher speed(s) PHY extension to 802.11b.
Project purpose: To
develop a new PHY extension to enhance the performance and the possible
applications of the 802.11b compatible networks by increasing the data
rate achievable by such devices. This technology will be beneficial for
improved access to fixed network LAN and inter-network infrastructure
(including access to other wireless LANs) via a network of access points,
as well as creation of higher performance ad hoc
networks.
--------------------------------------------------------------------------------
Designation: 802.11h
Project scope: Enhance
the 802.11 Medium Access Control (MAC) standard and 802.11a High Speed
Physical Layer (PHY) in the 5GHz Band supplement to the standard; to add
indoor and outdoor channel selection for 5GHz license exempt bands in
Europe; and to enhance channel energy measurement and reporting mechanisms
to improve spectrum and transmit power management (per CEPT and subsequent
EU committee or body ruling incorporating CEPT Recommendation ERC 99/23).
Project purpose: To
enhance the current 802.11 MAC and 802.11a PHY with network management and
control extensions for spectrum and transmit power management in 5GHz
license exempt bands, enabling regulatory acceptance of 802.11 5GHz
products. Provide improvements in channel energy measurement and
reporting, channel coverage in many regulatory domains, and provide
Dynamic Channel Selection and Transmit Power Control mechanisms.
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