IEEE 802.11af

In the United States, the Federal Communications Commission (FCC) permits TV white space operation in 6 MHz channels between 54 and 698 MHz in TV channels 2, 5, 6, 14–35, and 38–51, with the geolocation database granting use for up to 48 hours. For mobile stations, allowed transmit power is fixed to 100 mW per 6 MHz channel, or 40 mW if an adjacent channel is in use by a primary user. In the European Union, the European Telecommunications Standards Institute (ETSI) and Ofcom permit TV white space operation in 8 MHz channels between 490 and 790 MHz, with the GDB granting use for up to 2 hours.


WiFiwireless internetwireless
The 802.11 standard provides several distinct radio frequencies ranges for use in Wi-FI communications: 900 MHz, 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, 5.9 GHz, and 60 GHz bands. Each range is divided into a multitude of channels. Countries apply their own regulations to the allowable channels, allowed users and maximum power levels within these frequency ranges. The ISM band ranges are also often used. 802.11b/g/n can use the 2.4 GHz ISM band, operating in the United States under Part 15 Rules and Regulations. In this frequency band equipment may occasionally suffer interference from microwave ovens, cordless telephones, USB3.0 hubs, and Bluetooth devices.

Ultra high frequency

UHFUHF bandUHF radio
Public safety, business communications and personal radio services such as GMRS, PMR446, and UHF CB are often found on UHF frequencies as well as IEEE 802.11 wireless LANs ("Wi-Fi"). The widely adopted GSM and UMTS cellular networks use UHF cellular frequencies. Radio repeaters are used to retransmit UHF signals when a distance greater than the line of sight is required. Occasionally when conditions are right, UHF radio waves can travel long distances by tropospheric ducting as the atmosphere warms and cools throughout the day. The length of an antenna is related to the length of the radio waves used.

TV White Space Database

Geolocation DatabaseWhite spaces (database)centralized servers
The amount of white space that can be reclaimed for broadband access is directly related to regulations governing white space access in a country. Currently, spectrum regulators from several countries have determined the set of rules to access white space in a secondary manner and which database operators must follow in order to be authorized for service provision. Particularly, in the US, the FCC had originally limited secondary access to white space spectrum based on a fixed transmit power rule. TV White Space was available to secondary devices provided that these kept a safe distance from the broadcaster contour, depending only on the antenna's altitude and not transmit power.

IEEE 802.11y-2008

3.63650–3700 MHzy
The problem is that usage by the primary services in these bands may change over time (as is the case with some radar systems) or vary by sub-channel based on location (as is the case in the TV bands "white spaces") 802.11y, along with the continued advances in multi-band radio technology, may provide a solution to this problem by granting channel access dynamically to users based on primary user avoidance techniques, location and time. The enabling station (aka the licensee's base station) may or may not be the access point that the dependent STA connects to. In fact, an enabling station may enable both an access point and its clients.

Cognitive radio

autonomous interference cognitionCognitive communicationscognitive radio networks
The IEEE 802.22 working group is developing a standard for wireless regional area network (WRAN), which will operate on unused television channels, also known as TV white spaces. Unlicensed-Band Cognitive Radio, which can only utilize unlicensed parts of the radio frequency (RF) spectrum. One such system is described in the IEEE 802.15 Task Group 2 specifications, which focus on the coexistence of IEEE 802.11 and Bluetooth. Spectrum mobility: Process by which a cognitive-radio user changes its frequency of operation.

IEEE 802.11ah

802.11ahahTarget Wake Time
More specifically, 802.11af operates in the TV white space spectrum in the VHF and UHF bands between 54 and 790 MHz using cognitive radio technology. The following organisations sell 802.11ah compatible IP components: To date no commercial Wi-Fi HaLow chipsets are available on the market, below a list of companies that are part of Wi-Fi Alliance and are publicly developing Wi-Fi HaLow chipsets: To date no commercial Wi-Fi HaLow access points or routers are available on the market as these depend on Wi-Fi HaLow chipsets. Adapt-IP. IMEC. Methods2Business. Morse Micro. Newratek. Palma Ceia SemiDesign. Classic WaveLAN (pre-802.11 hardware with a 915MHz variant). IEEE.

Radio frequency

RFradio frequenciesradio-frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around twenty thousand times per second (20 kHz) to around three hundred billion times per second (300 GHz). This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range.

Very high frequency

VHFVHF radioVHF band
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).

Internet access

broadband internetbroadbandbroadband Internet access
White spaces (radio), a group of technology companies working to deliver broadband Internet access via unused analog television frequencies. European broadband. Corporate vs. Community Internet, AlterNet, June 14, 2005, – on the clash between US cities' attempts to expand municipal broadband and corporate attempts to defend their markets. Broadband data, from Google public data. US National Broadband Maps. Types of Broadband Connections, Check Internet Speed, NETSPEED.

Wireless broadband

broadband wirelessbroadband wireless accessBWA
In 2010 the FCC adopted the TV White Space Rules (TVWS) and allowed some of the better no line of sight frequency (700 MHz) into the FCC Part-15 Rules. The Wireless Internet Service Providers Association, a national association of WISPs, petitioned the FCC and won. Initially, WISPs were only found in rural areas not covered by cable or DSL. These early WISPs would employ a high-capacity T-carrier, such as a T1 or DS3 connection, and then broadcast the signal from a high elevation, such as at the top of a water tower. To receive this type of Internet connection, consumers mount a small dish to the roof of their home or office and point it to the transmitter.

Wireless LAN

WLANwireless local area networkwireless
The IEEE 802.11 has two basic modes of operation: infrastructure and ad hoc mode. In ad hoc mode, mobile units transmit directly peer-to-peer. In infrastructure mode, mobile units communicate through an access point that serves as a bridge to other networks (such as Internet or LAN). Since wireless communication uses a more open medium for communication in comparison to wired LANs, the 802.11 designers also included encryption mechanisms: Wired Equivalent Privacy (WEP, now insecure), Wi-Fi Protected Access (WPA, WPA2, WPA3), to secure wireless computer networks.


The primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE 802.11. Ethernet was developed at Xerox PARC between 1973 and 1974. It was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. The idea was first documented in a memo that Metcalfe wrote on May 22, 1973, where he named it after the luminiferous aether once postulated to exist as an "omnipresent, completely-passive medium for the propagation of electromagnetic waves." In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, and Butler Lampson as inventors.

List of WLAN channels

2.4 GHzwireless channel2.4
(IEEE 802.11-2007 §19.4.2) Electromagnetic interference at 2.4 GHz. High Speed Multimedia Radio. IEEE 802.11#Layer 2 .E2.80.93 Datagrams. Wireless LAN.

Wi-Fi Alliance

Wi-Fi EasyMeshWireless Ethernet Compatibility Alliance
Not every IEEE 802.11-compliant device is submitted for certification to the Wi-Fi Alliance, sometimes because of costs associated with the certification process. The lack of the Wi-Fi logo does not necessarily imply a device is incompatible with Wi-Fi devices. The Wi-Fi Alliance owns the Wi-Fi trademark. Manufacturers may use the trademark to brand certified products that have been tested for interoperability. Early 802.11 products suffered from interoperability problems because the Institute of Electrical and Electronics Engineers (IEEE) had no provision for testing equipment for compliance with its standards.


Classic WaveLAN
WaveLAN laid the important foundation for the formation of IEEE 802.11 working group and the resultant creation of Wi-Fi. WaveLAN has been used on two different families of wireless technology: WaveLAN was originally designed by COMTEN, a subsidiary of NCR Corporation, (later the Network Products Division of NCR) in 1986-7, and introduced to the market in 1988 as a wireless alternative to Ethernet and Token-Ring. The next year NCR contributed the WaveLAN design to the IEEE 802 LAN/MAN Standards Committee. This led to the founding of the 802.11 Wireless LAN Working Committee which produced the original IEEE 802.11 standard, which eventually became known popularly as Wi-Fi.

List of 2.4 GHz radio use

2.4 GHzElectromagnetic interference at 2.4 GHzinterference in the 2.4 GHz band
To avoid interference from IEEE 802.11 networks, an IEEE 802.15.4 network can be configured to only use channels 15, 20, 25, and 26, avoiding frequencies used by the commonly used IEEE 802.11 channels 1, 6, and 11. Wireless Microphones operate as transmitters. Some digital wireless microphones use the 2.4 GHz band (e.g. AKG model DPT 70). Normally interference is not too hard to find. Products are coming onto the market cheaply which act as spectrum analyzers and use a standard USB interface into a laptop, meaning that the interference source can be fairly easily found with a little work, a directional antenna and driving around to find the interference.

IEEE 802.22

802.22wireless regional area network
In addition to 802.22, the IEEE has standardized another white space cognitive radio standard, 802.11af. While 802.22 is a wireless regional area network (WRAN) standard, for ranges up to 100 km, 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 and based on various coexistence techniques. IEEE 802.11af, a standard for wireless LANs in TV white space. Geolocation Database.

IEEE 802.2

LLC may offer three types of services: Conversely, 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.

Carrier-sense multiple access with collision avoidance

CSMA/CAcarrier sense multiple access with collision avoidancecollision avoidance
IEEE 802.11 RTS/CTS. Network allocation vector. Truncated binary exponential backoff.

IEEE 802.11b-1999

b802.11bIEEE 802.11b
More information can be found in the List of WLAN channels.'' ja:IEEE 802.11#IEEE 802.11b IEEE 802.11. IEEE 802.11g-2003. Wi-Fi. List of WLAN channels.