Wireless 802.11 Standards

The Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a working group of the IEEE 802 LAN/MAN Standards Committee (IEEE 802 LMSC). The goal of the 802.11 Working Group is to develop the physical (PHY) and the media access control (MAC) layer standards for wireless LAN.

We'll examine the wireless standards that the IEEE 802 LMSC has approved and those that are up and coming. Our focus is 802.11, the wireless LAN working group. We explain the major differences between various 802.11 standards, their operation, interoperability, and deployment constraints.

In the paragraphs that follow we discuss a brief history of the IEEE; IEEE working groups responsible for development of wireless LAN standards; a basic overview of 802.11 standard, extensions, and its shortcomings; and a brief comparison of the IEEE 802 wireless standards.

First, to understand the significance of the IEEE and the importance of its involvement in the development of the wireless LAN standards, let's look at the history of the IEEE.

The existence of the IEEE dates to May 13, 1884, when the American Institute of Electrical Engineers (AIEE) was formed in New York City. AIEE played an active role in the development of electrical industry standards, which focus primarily on the wired communications, light, and power systems.

In the early 1900s the Society of Wireless and Telegraph Engineers and the Wireless Institute, two separate organizations working on wireless communication standards, merged to form the Institute of Radio Engineers (IRE).

Though the majority of work done by the IRE was radio communications related, it heavily utilized the advancement in electronics and electrical engineering—an area that was the primary focus of the AIEE.

The work done by both the AIEE and the IRE was similar in many respects; hence, many members of the IRE were also members of the AIEE. Recognizing the common goals that both organizations had, their leaders decided to merge the two to form one organization, which would perform the tasks performed by both organizations.

The two organizations finally merged on January 1, 1961, to form IEEE. Since 1961, IEEE has played an extremely important role in electrical industry standards development and academics.

Today, IEEE has over 377,342 members around the world, its standards are widely accepted, and it publishes over 75 journals and magazines that define the future of the electrical industry.

Within IEEE, most standards−related work is performed by its committees. These committees normally have working groups that deal with a committee−assigned subarea.

Depending on the complexity, working groups often designate task groups that do most of the groundwork. The working group first approves the work of the task group, which finally becomes a standard pending approval from the government agencies (if necessary) and the committee that work group reports to.

Today, almost all computer network standards are IEEE−compliant. The IEEE 802 LAN/MAN Standards Committee (IEEE 802 LMSC) was formed in 1980 to develop and propose standards for LANs.

The most commonly used LAN standards 802.3 (Ethernet or CSMA/CD) and 802.5 (token ring) were both developed by IEEE. Today, there are 17 different working groups that operate under the authority of IEEE 802 LMSC.

Each working group is named after its standards committee and is identified by a numerical value. For example, 802.11 is an IEEE 802 LMSC working group for wireless LAN.

IEEE 802 Wireless Standards

The scope of the IEEE 802 LMSC Committee has grown since its inception in 1980. Today, there are three basic wireless working groups within the IEEE 802 LMSC: the IEEE 802.11 for wireless LANs, the IEEE 802.15 for personal area networks (PANs), and the IEEE 802.16 for broadband wireless solutions.

The 802.11 Working Group

The IEEE 802.11 was formed in July 1990 to develop CSMA/CA, a variation of CSMA/CD (Ethernet)−based wireless LANs. The working group produced the first 802.11 standard in 1997, which specifies wireless LAN devices capable of operating up to 2 Mbps using the unlicensed 2.4−GHz band.

Currently, the working group has nine basic task groups and each is identified by a letter from a to i. Following are the current 802.11 task groups and their primary responsibilities:

  • 802.11a. Provides a 5−GHz band standard for 54−Mbps transmission rate.
  • 802.11b. Specifies a 2.4−GHz band standard for up to 11−Mbps transmission rate.
  • 802.11c. Gives the required 802.11−specific information to the ISO/IEC 10038 (IEEE 802.1D) standard.
  • 802.11d. Adds the requirements and definitions necessary to allow 802.11 wireless LAN equipment to operate in markets not served by the current 802.11 standard.
  • 802.11e. Expands support for LAN applications with Quality of Service requirements.
  • 802.11f. Specifies the necessary information that needs to be exchanged between access points to support the P802.11 DS functions.
  • 802.11g. Develops 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.
  • 802.11h. Enhances the current 802.11 MAC and 802.11a PHY with network management and control extensions for spectrum and transmit power management in 5−GHz license exempt bands.
  • 802.11i. Enhances the current 802.11 MAC to provide improvements in security.

The 802.15 Working Group

The IEEE 802.15 Working Group first met in July 1999. The working group develops standards and recommends practices for short−distance wireless networks known as wireless personal area networks (WPANs).

These WPANs address the needs of personal digital assistants (PDAs), personal computers (PCs), cell phones, and wireless payment systems.

The WPAN−compliant devices are supposed to operate within the personal operating space (POS) that typically extends about a radius of 5 meters from a WPAN device. A number—for example, 802.15.1—denotes the projects and the task groups of 802.15.

The working group currently has the following four projects:

  • 802.15.1. A WPAN standard for Bluetooth
  • 802.15.2. A coexistence guideline for license−exempt devices
  • 802.15.3. A high−rate WPAN standard
  • 802.15.4. A low−rate WPAN standard

The most widely implemented standard of the 802.15 Working Group is 802.15.1, which uses Bluetooth technology and operates in the 2.4−GHz ISM band.

The 802.16 Working Group

The 802.16 Working Group was formed in July of 1999 for developing standards and recommending practices for the development and deployment of fixed broadband wireless access systems.

The working group has the following three projects:

  • 802.16. Air Interface for 10–66 GHz Recommended practice for coexistence among 802.16 and 802.16a devices
  • 802.16a. Amendments to the MAC layer and an additional PHY layer for 2–11 GHz licensed frequencies
  • 802.16b. Amendments to the MAC layer and an additional PHY layer, license−exempt frequencies, with a focus on 5–6 GHz