802 11 and 802 16 standards
 


IEEE 802.16 is a series of Wireless Broadband standards authored by the Institute of Electrical and Electronics Engineers (IEEE). The IEEE Standards Board established a working group in 1999 to develop standards for broadband for Wireless Metropolitan Area Networks. The Workgroup is a unit of the IEEE 802 local area network and metropolitan area network standards committee.

Although the 802.16 family of standards is officially called WirelessMAN in IEEE, it has been commercialized under the name “WiMAX” (from "Worldwide Interoperability for Microwave Access") by the WiMAX Forum industry alliance. The Forum promotes and certifies compatibility and interoperability of products based on the IEEE 802.16 standards.

The 802.16e-2005 amendment version was announced as being deployed around the world in 2009. The version IEEE 802.16-2009 was amended by IEEE 802.16j-2009.

Standards

Projects publish draft and proposed standards with the letter "P" prepended, which gets dropped and replaced by a dash and year when the standards are ratified and published.

Projects

Standard Description Status
802.16-2001 Fixed Broadband Wireless Access (10–66 GHz) Superseded
802.16.2-2001 Recommended practice for coexistence Superseded
802.16c-2002 System profiles for 10–66 GHz Superseded
802.16a-2003 Physical layer and MAC definitions for 2–11 GHz Superseded
P802.16b License-exempt frequencies
(Project withdrawn)
Withdrawn
P802.16d Maintenance and System profiles for 2–11 GHz
(Project merged into 802.16-2004)
Merged
802.16-2004 Air Interface for Fixed Broadband Wireless Access System
(rollup of 802.16-2001, 802.16a, 802.16c and P802.16d)
Superseded
P802.16.2a Coexistence with 2–11 GHz and 23.5–43.5 GHz
(Project merged into 802.16.2-2004)
Merged
802.16.2-2004 Recommended practice for coexistence
(Maintenance and rollup of 802.16.2-2001 and P802.16.2a)
Current
802.16f-2005 Management Information Base (MIB) for 802.16-2004 Superseded
802.16-2004/Cor 1-2005 Corrections for fixed operations
(co-published with 802.16e-2005)
Superseded
802.16e-2005 Mobile Broadband Wireless Access System Superseded
802.16k-2007 Bridging of 802.16
(an amendment to IEEE 802.1D)
Current
802.16g-2007 Management Plane Procedures and Services Superseded
P802.16i Mobile Management Information Base
(Project merged into 802.16-2009)
Merged
802.16-2009 Air Interface for Fixed and Mobile Broadband Wireless Access System
(rollup of 802.16-2004, 802.16-2004/Cor 1, 802.16e, 802.16f, 802.16g and P802.16i)
Current
802.16j-2009 Multihop relay Current
802.16h-2010 Improved Coexistence Mechanisms for License-Exempt Operation Current
802.16m-2011 Advanced Air Interface with data rates of 100 Mbit/s mobile and 1 Gbit/s fixed.
Also known as Mobile WiMAX Release 2 or WirelessMAN-Advanced.
Aiming at fulfilling the ITU-R IMT-Advanced requirements on 4G systems.
Current
P802.16n Higher Reliability Networks In Progress
P802.16p Enhancements to Support Machine-to-Machine Applications In Progress

802.16e-2005 Technology

The 802.16 standard essentially standardizes two aspects of the air interface - the physical layer (PHY) and the Media Access Control layer (MAC). This section provides an overview of the technology employed in these two layers in the mobile 802.16e specification.

PHY

802.16e uses Scalable OFDMA to carry data, supporting channel bandwidths of between 1.25 MHz and 20 MHz, with up to 2048 sub-carriers. It supports adaptive modulation and coding, so that in conditions of good signal, a highly efficient 64 QAM coding scheme is used, whereas when the signal is poorer, a more robust BPSK coding mechanism is used. In intermediate conditions, 16 QAM and QPSK can also be employed. Other PHY features include support for Multiple-in Multiple-out (MIMO) antennas in order to provide good non-line-of-sight propagation (NLOS) characteristics (or higher bandwidth) and Hybrid automatic repeat request (HARQ) for good error correction performance.

Although the standards allow operation in any band from 2 to 66 GHz, mobile operation is best in the lower bands which are also the most crowded, and therefore most expensive.

MAC

The 802.16 MAC describes a number of Convergence Sublayers which describe how wireline technologies such as Ethernet, Asynchronous Transfer Mode (ATM) and Internet Protocol (IP) are encapsulated on the air interface, and how data is classified, etc. It also describes how secure communications are delivered, by using secure key exchange during authentication, and encryption using Advanced Encryption Standard (AES) or Data Encryption Standard (DES) during data transfer. Further features of the MAC layer include power saving mechanisms (using Sleep Mode and Idle Mode) and handover mechanisms.

A key feature of 802.16 is that it is a connection oriented technology. The subscriber station (SS) cannot transmit data until it has been allocated a channel by the Base Station (BS). This allows 802.16e to provide strong support for Quality of Service (QoS).

QoS

Quality of service (QoS) in 802.16e is supported by allocating each connection between the SS and the BS (called a service flow in 802.16 terminology) to a specific QoS class. In 802.16e, there are 5 QoS classes:

802.16e-2005 QoS classes
Service Abbrev Definition Typical Applications
Unsolicited Grant Service UGS Real-time data streams comprising fixed-size data packets issued at periodic intervals T1/E1 transport
Extended Real-time Polling Service ertPS Real-time service flows that generate variable-sized data packets on a periodic basis VoIP
Real-time Polling Service rtPS Real-time data streams comprising variable-sized data packets that are issued at periodic intervals MPEG Video
Non-real-time Polling Service nrtPS Delay-tolerant data streams comprising variable-sized data packets for which a minimum data rate is required FTP with guaranteed minimum throughput
Best Effort BE Data streams for which no minimum service level is required and therefore may be handled on a space-available basis HTTP

The BS and the SS use a service flow with an appropriate QoS class (plus other parameters, such as bandwidth and delay) to ensure that application data receives QoS treatment appropriate to the application.


IEEE 802.11 is a set of standards for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee (IEEE 802). The base version of the standard IEEE 802.11-2012 has had subsequent amendments. These standards provide the basis for wireless network products using the Wi-Fi brand.

 

Protocols

  • A1 A2 IEEE 802.11y-2008 extended operation of 802.11a to the licensed 3.7 GHz band. Increased power limits allow a range up to 5,000 m. As of 2009, it is only being licensed in the United States by the FCC.
  • B1 B2 Assumes short guard interval (SGI) enabled, otherwise reduce each data rate by 10%.
802.11 network standards
802.11
protocol
Release Freq.
(GHz)
Bandwidth
(MHz)
Data rate per stream
(Mbit/s)
Allowable
MIMO streams
Modulation Approximate indoor range Approximate outdoor range
(m) (ft) (m) (ft)
Jun 1997 2.4 20 1, 2 1 DSSS, FHSS 20 66 100 330
a Sep 1999 5 20 6, 9, 12, 18, 24, 36, 48, 54 1 OFDM 35 115 120 390
3.7 5,000 16,000
b Sep 1999 2.4 20 1, 2, 5.5, 11 1 DSSS 35 115 140 460
g Jun 2003 2.4 20 6, 9, 12, 18, 24, 36, 48, 54 1 OFDM, DSSS 38 125 140 460
n Oct 2009 2.4/5 20 7.2, 14.4, 21.7, 28.9, 43.3, 57.8, 65, 72.2 4 OFDM 70 230 250 820
40 15, 30, 45, 60, 90, 120, 135, 150 70 230 250 820
ac (DRAFT) Nov. 2011 5 20 up to 87.6 8        
40 up to 200        
80 up to 433.3        
160 up to 866.7        

802.11-1997 (802.11 legacy)

Main article: IEEE 802.11 (legacy mode)

The original version of the standard IEEE 802.11 was released in 1997 and clarified in 1999, but is today obsolete. It specified two net bit rates of 1 or 2 megabits per second (Mbit/s), plus forward error correction code. It specified three alternative physical layer technologies: diffuse infrared operating at 1 Mbit/s; frequency-hopping spread spectrum operating at 1 Mbit/s or 2 Mbit/s; and direct-sequence spread spectrum operating at 1 Mbit/s or 2 Mbit/s. The latter two radio technologies used microwave transmission over the Industrial Scientific Medical frequency band at 2.4 GHz. Some earlier WLAN technologies used lower frequencies, such as the U.S. 900 MHz ISM band.

Legacy 802.11 with direct-sequence spread spectrum was rapidly supplanted and popularized by 802.11b.

802.11a

Main article: IEEE 802.11a-1999

The 802.11a standard uses the same data link layer protocol and frame format as the original standard, but an OFDM based air interface (physical layer). It operates in the 5 GHz band with a maximum net data rate of 54 Mbit/s, plus error correction code, which yields realistic net achievable throughput in the mid-20 Mbit/s.

Since the 2.4 GHz band is heavily used to the point of being crowded, using the relatively unused 5 GHz band gives 802.11a a significant advantage. However, this high carrier frequency also brings a disadvantage: the effective overall range of 802.11a is less than that of 802.11b/g. In theory, 802.11a signals are absorbed more readily by walls and other solid objects in their path due to their smaller wavelength and, as a result, cannot penetrate as far as those of 802.11b. In practice, 802.11b typically has a higher range at low speeds (802.11b will reduce speed to 5 Mbit/s or even 1 Mbit/s at low signal strengths). 802.11a also suffers from interference, but locally there may be fewer signals to interfere with, resulting in less interference and better throughput.

802.11b

Main article: IEEE 802.11b-1999

802.11b has a maximum raw data rate of 11 Mbit/s and uses the same media access method defined in the original standard. 802.11b products appeared on the market in early 2000, since 802.11b is a direct extension of the modulation technique defined in the original standard. The dramatic increase in throughput of 802.11b (compared to the original standard) along with simultaneous substantial price reductions led to the rapid acceptance of 802.11b as the definitive wireless LAN technology.

802.11b devices suffer interference from other products operating in the 2.4 GHz band. Devices operating in the 2.4 GHz range include microwave ovens, Bluetooth devices, baby monitors, cordless telephones and some amateur radio equipment.

802.11g

Main article: IEEE 802.11g-2003

In June 2003, a third modulation standard was ratified: 802.11g. This works in the 2.4 GHz band (like 802.11b), but uses the same OFDM based transmission scheme as 802.11a. It operates at a maximum physical layer bit rate of 54 Mbit/s exclusive of forward error correction codes, or about 22 Mbit/s average throughput. 802.11g hardware is fully backward compatible with 802.11b hardware and therefore is encumbered with legacy issues that reduce throughput when compared to 802.11a by ~21%.

The then-proposed 802.11g standard was rapidly adopted by consumers starting in January 2003, well before ratification, due to the desire for higher data rates as well as to reductions in manufacturing costs. By summer 2003, most dual-band 802.11a/b products became dual-band/tri-mode, supporting a and b/g in a single mobile adapter card or access point. Details of making b and g work well together occupied much of the lingering technical process; in an 802.11g network, however, activity of an 802.11b participant will reduce the data rate of the overall 802.11g network.

Like 802.11b, 802.11g devices suffer interference from other products operating in the 2.4 GHz band, for example wireless keyboards.

802.11-2007

In 2003, task group TGma was authorized to "roll up" many of the amendments to the 1999 version of the 802.11 standard. REVma or 802.11ma, as it was called, created a single document that merged 8 amendments (802.11a, b, d, e, g, h, i, j) with the base standard. Upon approval on March 8, 2007, 802.11REVma was renamed to the then-current base standard IEEE 802.11-2007.

802.11n

802.11n is an amendment which improves upon the previous 802.11 standards by adding multiple-input multiple-output antennas (MIMO). 802.11n operates on both the 2.4 GHz and the lesser used 5 GHz bands. It operates at a maximum net data rate from 54 Mbit/s to 600 Mbit/s. The IEEE has approved the amendment and it was published in October 2009. Prior to the final ratification, enterprises were already migrating to 802.11n networks based on the Wi-Fi Alliance's certification of products conforming to a 2007 draft of the 802.11n proposal.

802.11-2012

In 2007, task group TGmb was authorized to "roll up" many of the amendments to the 2007 version of the 802.11 standard. REVmb or 802.11mb, as it was called, created a single document that merged ten amendments (802.11k, r, y, n, w, p, z, v, u, s) with the 2007 base standard. In addition much cleanup was done, including a reordering of many of the clauses. Upon publication on March 29, 2012, the new standard was referred to as IEEE 802.11-2012.

802.11ac

IEEE 802.11ac is a standard under development which will provide high throughput in the 5 GHz band. This specification will enable multi-station WLAN throughput of at least 1 gigabits per second and a maximum single link throughput of at least 500 megabits per second, by using wider RF bandwidth (80 or 160 MHz), more streams (up to 8), and high-density modulation (up to 256 QAM).

802.11ad

IEEE 802.11ad "WiGig" is a new proposed standard that is already seeing a major push from hardware manufacturers. On 24 July 2012 Marvell and Wilocity announced a new partnership to bring a new tri-band Wi-Fi solution to market. Using 2.4 GHz, 5 GHz and 60 GHz, the new standard can achieve a theoretical maximum throughput of up to 7Gbit/s. This standard is expected to reach the market sometime in early 2014.