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In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
 Working Group on Broadband Wireless Access Standards |
IEEE 802.16 is a series of wireless broadband standards written 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 was implemented and deployed around the world as of 2009[update].[1] The version IEEE 802.16-2009 was amended by IEEE 802.16j-2009.
Projects publish draft and proposed standards with the letter "P" prefixed. Once a standard is ratified and published, that "P" gets dropped and replaced by a trailing dash and suffix year of publication.
| Standard | Description | Status |
|---|---|---|
| 802.16 | Fixed Broadband Wireless Access (10–66 GHz) | Superseded |
| 802.16.2 | Recommended practice for coexistence | Superseded |
| 802.16c | System profiles for 10–66 GHz | Superseded |
| 802.16a | Physical layer and MAC definitions for 2–10 GHz | Superseded |
| P802.16b | License-exempt frequencies (Project withdrawn) |
Withdrawn |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 | 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Superseded |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 | IEEE Recommended Practice for Local and metropolitan area networks Coexistence of Fixed Broadband Wireless Access Systems (Maintenance and rollup of 802.16.2–2001 and P802.16.2a) Released on 2004-March-17. |
Existing |
| 802.16f | 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 | Mobile Broadband Wireless Access System | Superseded |
| 802.16k | IEEE Standard for Local and Metropolitan Area Networks: Media Access Control (MAC) Bridges Amendment 2: Bridging of IEEE 802.16 (An amendment to IEEE 802.1D) Released on 2007-August-14. |
Existing |
| 802.16g | 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) |
Superseded |
| 802.16j | Multihop relay | Superseded |
| 802.16h | Improved Coexistence Mechanisms for License-Exempt Operation | Superseded |
| 802.16m | 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. |
Superseded[2] |
| 802.16-2012 | IEEE Standard for Air Interface for Broadband Wireless Access Systems It is a rollup of 802.16h, 802.16j and Std 802.16m (but excluding the WirelessMAN-Advanced radio interface, which was moved to IEEE Std 802.16.1). Released on 2012-August-17. |
Superseded |
| 802.16.1 | IEEE Standard for WirelessMAN-Advanced Air Interface for Broadband Wireless Access Systems Released on 2012-September-07. |
Existing |
| 802.16p | IEEE Standard for Air Interface for Broadband Wireless Access Systems Amendment 1: Enhancements to Support Machine-to-Machine Applications Released on 2012-October-08. |
Existing |
| 802.16.1b | IEEE Standard for WirelessMAN-Advanced Air Interface for Broadband Wireless Access Systems Amendment 1: Enhancements to Support Machine-to-Machine Applications Released on 2012-October-10. |
Existing |
| 802.16n | IEEE Standard for Air Interface for Broadband Wireless Access Systems Amendment 2: Higher Reliability Networks Approved on 2013-March-06. |
Existing |
| 802.16.1a | IEEE Standard for WirelessMAN-Advanced Air Interface for Broadband Wireless Access Systems Amendment 2: Higher Reliability Networks Approved on 2013-March-06. |
Existing |
| 802.16-2017 | IEEE Standard for Air Interface for Broadband Wireless Access Systems It is a rollup of 802.16p, 802.16n, 802.16q (Multi-tier Networks) and Std 802.16s (licensed spectrum, bandwidth 0.1–1.25 MHz) Released on 2017-September. |
Existing |
| 802.16t | Amendment - Fixed and Mobile Wireless Access in Narrowband Channels, a new PHY for licensed spectrum operation with bandwidths of 5–100 kHz. Approved 2020-12-03. |
Existing |
The 802.16 standard essentially standardizes two aspects of the air interface – the physical layer (PHY) and the media access control (MAC) layer. This section provides an overview of the technology employed in these two layers in the mobile 802.16e specification.
802.16e uses scalable orthogonal frequency-division multiple access (OFDMA) to carry data, supporting channel bandwidths of between 1.25 MHz and 20 MHz, with up to 2048 subcarriers. It supports adaptive modulation and coding, so that in conditions of good signal, a highly efficient 64 QAM (Quadrature amplitude modulation) coding scheme is used, whereas when the signal is poorer, a more robust binary phase-shift keying (BPSK) coding mechanism is used. In intermediate conditions, 16 QAM and QPSK can also be employed. Other PHY features include support for multiple-input multiple-output (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.[3]
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).
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 five 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[citation needed] |
| 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.
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.
Cellular network standards | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 0G radio telephones (1946) | |||||||||
| 1G (1979) |
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| 2G (1991) |
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| 2G transitional (2.5G, 2.75G, 2.9G) |
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| 3G (1998) IMT-2000 (2001) |
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| 3G transitional (3.5G, 3.75G, 3.9G) |
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| 4G (2009) IMT Advanced (2013) |
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| 5G (2018) IMT-2020 (2021) |
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| Related articles | |||||||||
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Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
IEEE 802.16 is a series of wireless broadband standards written 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 was implemented and deployed around the world as of 2009. The version IEEE 802.16-2009 was amended by IEEE 802.16j-2009.
IEEE 802.18, the Radio Regulatory Technical Advisory Group ("RR-TAG"), is a working group of IEEE 802, the LAN/MAN Standards Committee (LMCS). The working group currently has 6 projects on standards for radio-based systems: IEEE 802.11 (Wireless Local area network- WLAN) IEEE 802.15 (Wireless Personal area network - WPAN) IEEE 802.16 (Wireless Metropolitan area network - WMAN) IEEE 802.20 (Wireless Mobility) IEEE 802.21 (Hand-off/Interoperability Between Networks) IEEE 802.22 (Wireless Regional Area Network - WRAN). The RR-TAG monitors the interests of the above 6 projects, at both national and international levels, and then makes comments and recommends policies to regulators, which balance the interests of all the wireless LMCS projects.
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMAX Forum was formed in June 2001 to promote conformity and interoperability, including the definition of system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL". WiMAX was initially designed to provide 30 to 40 Mbit/s data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations. IEEE 802.16m or Wireless MAN-Advanced was a candidate for 4G, in competition with the LTE Advanced standard. WiMAX release 2.1, popularly branded as WiMAX 2+, is a backwards-compatible transition from previous WiMAX generations. It is compatible and interoperable with TD-LTE. Newer versions, still backward compatible, include WiMAX release 2.2 (2014) and WiMAX release 3 (2021, adds interoperation with 5G NR).
IEEE 802.2 is the original name of the ISO/IEC 8802-2 standard which defines logical link control (LLC) as the upper portion of the data link layer of the OSI Model. The original standard developed by the Institute of Electrical and Electronics Engineers (IEEE) in collaboration with the American National Standards Institute (ANSI) was adopted by the International Organization for Standardization (ISO) in 1998, but it remains an integral part of the family of IEEE 802 standards for local and metropolitan networks. LLC is a software component that provides a uniform interface to the user of the data link service, usually the network layer. LLC may offer three types of services: unacknowledged connectionless mode services (mandatory); connection mode services (optional); acknowledged connectionless mode services (optional). The LLC uses the services of the media access control (MAC), which is dependent on the specific transmission medium (Ethernet, Token Ring, FDDI, 802.11, etc.). Using LLC is compulsory for all IEEE 802 networks with the exception of Ethernet. It is also used in Fiber Distributed Data Interface (FDDI) which is not part of the IEEE 802 family. The IEEE 802.2 sublayer adds some control information to the message created by the upper layer and passed to the LLC for transmission to another node on the same data link. The resulting packet is generally referred to as LLC protocol data unit (PDU) and the additional information added by the LLC sublayer is the LLC HEADER. The LLC Header consist of DSAP (Destination Service Access Point), SSAP (Source Service Access Point) and the Control field. The two 8-bit fields DSAP and SSAP allow multiplexing of various upper layer protocols above LLC. However, many protocols use the Subnetwork Access Protocol (SNAP) extension which allows using EtherType values to specify the protocol being transported atop IEEE 802.2. It also allows vendors to define their own protocol value spaces. The 8 or 16 bit HDLC-style Control field serves to distinguish communication mode, to specify a specific operation and to facilitate connection control and flow control (in connection mode) or acknowledgements (in acknowledged connectionless mode).
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Madam C.J. Walker
