IEEE 802.16

IEEE 802.16

Working Group on Broadband Wireless Access 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.[1] The version IEEE 802.16-2009 was amended by IEEE 802.16j-2009.

Contents

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802.16-2001 Fixed Broadband Wireless Access (10–63 GHz) Superseded
802.16.2-2001 Recommended practice for coexistence Superseded
802.16c-2002 System profiles for 10–63 GHz Superseded
802.16a-2003 Physical layer and MAC definitions for 2–11 GHz Superseded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(Project withdrawn)
Withdrawn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Superseded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802.16f-2005 Management Information Base (MIB) for 802.16-2004 Superseded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Superseded
802.16e-2005 Mobile Broadband Wireless Access System Superseded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802.16g-2007 Management Plane Procedures and Services Superseded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[2]
P802.16n Higher Reliability Networks In Progress
P802.16p Enhancements to Support Machine-to-Machine Applications In Progress

Working group history

IEEE 802.16 standardizes the air interface and related functions associated with wireless local loop. The charter originally envisioned that three working groups would each produce a stand alone standard referred to as 802.16.1, 802.16.2 and 802.16.3. During development a decision was made that the first and third tasks were significantly related; the result was that two standards and an amendment were released.

802.16c, a further amendment to 802.16, delivered a system profile for the 10–66 GHz 802.16 standard.

In September 2003, a revision project called 802.16d commenced aiming to align the standard with aspects of the European Telecommunications Standards Institute (ETSI) HIPERMAN standard as well as lay down conformance and test specifications. This project concluded in 2004 with the release of 802.16-2004 which superseded the earlier 802.16 documents, including the a and c amendments.

An amendment to 802.16-2004, IEEE 802.16e-2005, addressing mobility, was concluded in 2005. This implemented a number of enhancements to 802.16-2004, including better support for Quality of Service and the use of Scalable OFDMA, and is sometimes called “Mobile WiMAX”, after the WiMAX forum for interoperability. The fixed and mobile variants of the protocol do not interoperate.[5] In 2007, the Radiocommunication Assembly of the International Telecommunication Union (ITU) approved IEEE 802.16e-2005 as meeting the "International Mobile Telecommunications 2000" requirements, which were generally meant for products marketed as 3G.[6]

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.[5]

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.

Certification

Because the IEEE only sets specifications but does not test equipment for compliance with them, the WiMAX Forum runs a certification program wherein members pay for certification. WiMAX certification by this group is intended to guarantee compliance with the standard and interoperability with equipment from other manufacturers. The mission of the Forum is to promote and certify compatibility and interoperability of broadband wireless products.

See also

References

  1. ^ "WiMAX™ operators and vendors from around the world announce new deployments, growing commitment at the 2nd Annual WiMAX Forum® Global Congress". News release (WiMAX Forum). June 4, 2009. http://www.wimaxforum.org/node/1161. Retrieved August 20, 2011. 
  2. ^ "IEEE Approves IEEE 802.16m - Advanced Mobile Broadband Wireless Standard". News release (IEEE Standards Association). March 31, 2011. http://standards.ieee.org/news/2011/80216m.html. Retrieved August 20, 2011. 
  3. ^ "IEEE 802.16 Task Group 1". IEEE Working Group on Broadband Wireless Access Standards. 2001. http://wirelessman.org/tg1/. Retrieved August 26, 2011. 
  4. ^ "IEEE 802.16 Coexistence Task Group (Task Group 2)". IEEE Working Group on Broadband Wireless Access Standards. 2004. http://wirelessman.org/tg2/. Retrieved August 26, 2011. 
  5. ^ a b Michael Richardson; Patrick Ryan (March 19, 2006). "WiMAX: Opportunity or Hype?". Advances in Telecom: Proceedings of the Fourth Annual ITERA Conference. SSRN 892260. 
  6. ^ "ITU Radiocommunication Assembly approves new developments for its 3G standards". News release. October 19, 2007. http://www.itu.int/newsroom/press_releases/2007/30.html. Retrieved August 26, 2011. 

External links