IEEE 802.22

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IEEE 802.22, is a standard for wireless regional area network (WRAN) using white spaces in the television (TV) frequency spectrum. [1] The development of the IEEE 802.22 WRAN standard is aimed at using cognitive radio (CR) techniques to allow sharing of geographically unused spectrum allocated to the television broadcast service, on a non-interfering basis, to bring broadband access to hard-to-reach, low population density areas, typical of rural environments, and is therefore timely and has the potential for a wide applicability worldwide. It is the first worldwide effort to define a standardized air interface based on CR techniques for the opportunistic use of TV bands on a non-interfering basis.

International standards are technical standards developed by international organizations, such as Codex Alimentarius in food, the World Health Organization Guidelines in health, or ITU Recommendations in ICT and being publicly funded, are freely available for consideration and use worldwide.

Television Telecommunication medium for transmitting and receiving moving images

Television (TV), sometimes shortened to tele or telly, is a telecommunication medium used for transmitting moving images in monochrome, or in colour, and in two or three dimensions and sound. The term can refer to a television set, a television program, or the medium of television transmission. Television is a mass medium for advertising, entertainment and news.

A cognitive radio (CR) is a radio that can be programmed and configured dynamically to use the best wireless channels in its vicinity to avoid user interference and congestion. Such a radio automatically detects available channels in wireless spectrum, then accordingly changes its transmission or reception parameters to allow more concurrent wireless communications in a given spectrum band at one location. This process is a form of dynamic spectrum management.


IEEE 802.22 WRANs are designed to operate in the TV broadcast bands while assuring that no harmful interference is caused to the incumbent operation: digital TV and analog TV broadcasting, and low power licensed devices such as wireless microphones. [2] The standard was expected to be finalized in Q1 2010, but was finally published in July 2011.

IEEE P802.22.1 is a related standard being developed to enhance harmful interference protection for low power licensed devices operating in TV Broadcast Bands. IEEE P802.22.2 is a recommended practice for the installation and deployment of IEEE 802.22 Systems. [1] IEEE 802.22 WG is a working group of IEEE 802 LAN/MAN standards committee which was chartered to write the 802.22 standard. The two 802.22 task groups (TG1 and TG2) are writing 802.22.1 and 802.22.2 respectively.

Working group interdisciplinary collaboration of researchers

A working group or working party is a group of experts working together to achieve specified goals. The groups are domain-specific and focus on discussion or activity around a specific subject area. The term can sometimes refer to an interdisciplinary collaboration of researchers working on new activities that would be difficult to sustain under traditional funding mechanisms.


In response to a notice of proposed rulemaking (NPRM) issued by the U.S. Federal Communications Commission (FCC) in May 2004, the IEEE 802.22 working group on Wireless Regional Area Networks was formed in October 2004. [3] Its project, formally called as Standard for Wireless Regional Area Networks (WRAN) - Specific requirements - Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Policies and procedures for operation in the TV Bands focused on constructing a consistent, national fixed point-to-multipoint WRAN that will use UHF/VHF TV bands between 54 and 862 MHz. Specific TV channels as well as the guard bands of these channels are planned to be used for communication in IEEE 802.22.

A notice of proposed rulemaking (NPRM) is a public notice issued by law when one of the independent agencies of the United States government wishes to add, remove, or change a rule or regulation as part of the rulemaking process. It is an important part of United States administrative law which facilitates government by typically creating a process of taking of public comment. This nomenclature is also utilized at the state level.

Federal Communications Commission Independent agency of the U.S. Government

The Federal Communications Commission (FCC) is an independent agency of the United States government created by statute to regulate interstate communications by radio, television, wire, satellite, and cable. The FCC maintains jurisdiction over the areas of broadband access, fair competition, radio frequency use, media responsibility, public safety, and homeland security.

The Institute of Electrical and Electronics Engineers (IEEE), together with the FCC, pursued a centralized approach for available spectrum discovery. Specifically each base station (BS) would be armed with a GPS receiver which would allow its position to be reported. This information would be sent back to centralized servers (in the USA these would be managed by the FCC), which would respond with the information about available free TV channels and guard bands in the area of the BS. Other proposals would allow local spectrum sensing only, where the BS would decide by itself which channels are available for communication. A combination of these two approaches is also envisioned. Devices which would operate in the TV white space band (TVWS) would be mainly of two types: Fixed and Personal/Portable. Fixed devices would have geolocation capability with an embedded GPS device. Fixed devices also communicate with the central database to identify other transmitters in the area operating in TVWS. Other measures suggested by the FCC and IEEE to avoid interference include dynamic spectrum sensing and dynamic power control.

Institute of Electrical and Electronics Engineers scholarly society, publisher and standards organization, headquartered in US

The Institute of Electrical and Electronics Engineers (IEEE) is a professional association for electronic engineering and electrical engineering with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers.

Base station

Base station is – according to the International Telecommunication Union's (ITU) Radio Regulations (RR) – a "land station in the land mobile service."

TV White Space database, also commonly referred to as geolocation database, is an entity that controls the TV spectrum utilization by unlicensed white spaces devices within a determined geographical area. Its sole objective is to enable unlicensed access to white space spectrum while protecting incumbent broadcasting services. TV White Space database was first brought as a way to overcome the technical hurdles faced by spectrum sensing techniques to precisely detect very weak primary signals.

Overview of the WRAN topology

The initial drafts of the 802.22 standard specify that the network should operate in a point to multipoint basis (P2MP). The system will be formed by base stations (BS) and customer-premises equipment (CPE). The CPEs will be attached to a BS via a wireless link. The BSs will control the medium access for all the CPEs attached to it.

In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation point ("demarc"). The demarc is a point established in a building or complex to separate customer equipment from the equipment located in either the distribution infrastructure or central office of the communications service provider.

One key feature of the WRAN Base Stations is that they will be capable of performing a cognitive sensing. This is that the CPEs will be sensing the spectrum and will be sending periodic reports to the BS informing it about what they sense. The BS, with the information gathered, will evaluate whether a change is necessary in the channel used, or on the contrary, if it should stay transmitting and receiving in the same one.

An approach to the PHY layer

The PHY layer must be able to adapt to different conditions and also needs to be flexible for jumping from channel to channel without errors in transmission or losing clients (CPEs). This flexibility is also required for being able to dynamically adjust the bandwidth, modulation and coding schemes. OFDMA will be the modulation scheme for transmission in up and downlinks. With OFDMA it will be possible to achieve this fast adaptation needed for the BS's and CPEs. By using just one TV channel (a TV channel has a bandwidth of 6 MHz; in some countries they can be of 7 or 8 MHz) the approximate maximum bit rate is 19 Mbit/s at a 30 km distance. The speed and distance achieved is not enough to fulfill the requirements of the standard. The feature Channel Bonding deals with this problem. Channel Bonding consists in using more than one channel for Tx / Rx. This allows the system to have higher bandwidth which will be reflected in a better system performance.

An approach to the MAC layer

This layer will be based on cognitive radio technology. It also needs to be able to adapt dynamically to changes in the environment by sensing the spectrum. The MAC layer will consist of two structures: Frame and Superframe. A superframe will be formed by many frames. The superframe will have a superframe control header (SCH) and a preamble. These will be sent by the BS in every channel that it's possible to transmit and not cause interference. When a CPE is turned on, it will sense the spectrum, find out which channels are available and will receive all the needed information to attach to the BS.

Two different types of spectrum measurement will be done by the CPE: in-band and out-of-band. The in-band measurement consists in sensing the actual channel that is being used by the BS and CPE. The out-of-band measurement will consist in sensing the rest of the channels. The MAC layer will perform two different types of sensing in either in-band or out-of-band measurements: fast sensing and fine sensing. Fast sensing will consist in sensing at speeds of under 1ms per channel. This sensing is performed by the CPE and the BS and the BS's will gather all the information and will decide if there is something new to be done. The fine sensing takes more time (approximately 25 ms per channel or more) and it is used based on the outcome of the previous fast sensing mechanism.

These sensing mechanisms are primarily used to identify if there is an incumbent transmitting, and if there is a need to avoid interfering with it.

To perform reliable sensing, in the basic operation mode on a single frequency band as described above (the "listen-before-talk" mode) one has to allocate quiet times, in which no data transmission is permitted. Such periodic interruption of data transmission could impair the QoS of cognitive radio systems. This issue is addressed by an alternative operation mode proposed in IEEE 802.22 called Dynamic frequency hopping (DFH) [4] where data transmission of the WRAN systems are performed in parallel with spectrum sensing without any interruption.

Encryption, authentication, and authorization

Only the AES-GCM authenticated encryption cipher algorithm is supported. [5]

EAP-TLS or EAP-TTLS must be used for authentication and encryption key derivation. [6] [7] IEEE 802.22 defines a X.509v3 certificate profile which uses extensions for authenticating and authorization of devices based on information such as device manufacturer, MAC address, and FCC ID (the Manufacturer/ServiceProvider certificate, the CPE certificate, and the BS certificate, respectively). [8]

This could allow for a type of customer lock-in where the network providers refuse network access to devices that have not been vetted by manufacturers of the network providers' choice (i.e. the device must possess a private key of a X.509 certificate with a chain of trust to a manufacturer certificate authority (CA) that the network provider will accept), not unlike the SIM lock in modern cellular networks and DOCSIS "certification testers" in cable networks.

Comparison with 802.11af

In addition to 802.22, the IEEE has standardized another white space cognitive radio standard, 802.11af. [9] While 802.22 is a wireless regional area network (WRAN) standard, for ranges up to 100 km, [9] [10] 802.11af is a wireless LAN standard designed for ranges up to 1 km. Coexistence between 802.22 and 802.11af standards can be implemented either in centralized or distributed manners [11] and based on various coexistence techniques. [12]

See also

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  1. 1 2 "IEEE 802 LAN/MAN Standards Committee 802.22 WG on WRANs (Wireless Regional Area Networks)". IEEE . Retrieved January 18, 2009.
  2. Carl, Stevenson; G. Chouinard; Zhongding Lei; Wendong Hu; S. Shellhammer; W. Caldwell (January 2009). "IEEE 802.22: The First Cognitive Radio Wireless Regional Area Networks (WRANs) Standard". IEEE Communications Magazine . Vol. 47 no. 1. US: IEEE. pp. 130–138. doi:10.1109/MCOM.2009.4752688.
  3. "IEEE Starts Standard to Tap Open Regions in the TV Spectrum for Wireless Broadband Services". News release. IEEE Standards Association. October 12, 2004. Archived from the original on February 7, 2009. Retrieved August 19, 2011.
  4. Wendong Hu; et al. (May 2007). "Dynamic Frequency Hopping Communities for Efficient IEEE 802.22 Operation". IEEE Communications Magazine. 45 (5): 80–87. doi:10.1109/MCOM.2007.358853 . Retrieved May 15, 2007.
  5. IEEE 802.22-2011 § 8.4.1, p. 281
  6. IEEE 802.22-2011 § 8.1.2, p. 252
  7. IEEE 802.22-2011 § 8.5, p. 286
  8. IEEE 802.22-2011 § 8.5, pp. 286-292
  9. 1 2 Lekomtcev, Demain; Maršálek, Roman (June 2012). "Comparison of 802.11af and 802.22 standards – physical layer and cognitive functionality". elektrorevue. Retrieved 2013-12-29.
  10. Thiel, Justin (2006–2007). "Metropolitan and Regional Wireless Networking: 802.16, 802.20 and 802.22" . Retrieved 2013-12-31.
  11. Villardi, Gabriel; Alemseged, Yohannes; Sun, Chen; Sum, Chin-Sean; Nguyen, Tran; Baykas, Tuncer; Harada, Hiroshi (2011). "Enabling Coexistence of Multiple Cognitive Networks in TV White Space". IEEE Wireless Communications. 18 (4): 32–40. doi:10.1109/MWC.2011.5999762.
  12. Villardi, Gabriel; Sum, Chin-Sean; Sun, Chen; Alemseged, Yohannes; Lan, Zhou; Harada, Hiroshi (2012). "Efficiency of Dynamic Frequency Selection Based Coexistence Mechanisms for TV White Space Enabled Cognitive Wireless Access Points". IEEE Wireless Communications. 19 (6): 69–75. doi:10.1109/MWC.2012.6393520.