362. Frequency Allocation

Dear Wikipedia readers: We are the small non-profit that runs the #5 website in the world. We have only 150 staff but serve 450 million users, and have costs like any other top site: servers, power, rent, programs, and staff. Wikipedia is something special. It is like a library or a public park. It is like a temple for the mind, a place we can all go to think and learn. To protect our independence, we'll never run ads. We take no government funds. We run on donations averaging about Rs. 1500. If everyone reading this gave Rs. 100, our fundraiser would be done within an hour. If Wikipedia is useful to you, take one minute to keep it online another year. Please help us forget fundraising and get back to Wikipedia. Thank you.

Please Help  

                         Frequency   Allocation

Use of radio frequency bands of the electromagnetic spectrum is regulated by governments in most countries, in a Spectrum management process known as frequency allocation or spectrum allocation. Radio propagation does not stop at national boundaries. Giving technical and economic reasons, governments have sought to harmonise the allocation of RF bands and their standardization.
A number of forums and standards bodies work on standards for frequency allocation, including:

• International Telecommunication Union (ITU)
• European Conference of Postal and Telecommunications Administrations (CEPT)
• European Telecommunications Standards Institute (ETSI)
• International Special Committee on Radio Interference (Comité international spécial des perturbations radioélectriques - CISPR)

These standards bodies have assigned frequency bands in three types of allocation:

• No one may transmit: frequencies reserved for radio astronomy to avoid interference at radio telescopes
• Anyone may transmit, as long as they respect certain transmission power and other limits: open spectrum bands such as the unlicensed ISM bands and the unlicensed ultra-wideband band, and the somewhat more regulated amateur radio frequency allocations. Often users use a "listen before talk" contention-based protocol.
• Only the licensed user of that band may transmit: the licensing body may give the same frequency to several users as a form of frequency reuse if they cannot interfere because their coverage map areas never overlap.

High-demand sections of the electromagnetic spectrum may sometimes be allocated through auctions.

Daily impact

Every day, users rely on allocation of frequencies for efficient use of such devices as:

• cell phone
• cordless phone
• garage door opener
• car key remote control
• broadcast television and audio
• Standard time broadcast
• vehicle-speed radar, air traffic radar, weather radar
• mobile radio
• Global Positioning System (GPS) navigation
• satellite TV broadcast reception; also backend signal dissemination
• Microwave oven
• Bluetooth
• Wifi
• Zigbee
• RFID devices such as active badges, passports, wireless gasoline token, no-contact credit-cards, and product tags
• toll-road payment vehicle transponders
• Citizen's band radio and Family Radio Service
• Radio control, including Radio-controlled model aircraft and vehicles
• wireless microphones and musical instrument links

Power levels vary widely (from 1 milliwatt in a Bluetooth node to 1 kilowatt in a microwave oven). While the general RF band controls propagation characteristics, who uses what is arbitrary and historical. A particular frequency may require line of sight, or may be attenuated by rain, but whether it carries ambulance or pizza delivery traffic depends on what region it's used in.
Earlier equipment could not process higher frequencies, nor was it compact enough to support certain uses. Over time the exploitable frequencies have increased and semiconductors have shrunk. A tube radio is neither mobile nor reasonably battery powered; GPS works at 1,500 MHz and fits in a pocket. A Bluetooth headset can talk to a mobile phone which is trunked on a microwave link, and at the other end someone is on a cordless phone.

International conventions

The range of "radio frequencies" is a matter of international convention. The separation of countries into the three formal ITU RF allocation regions is one source of different RF allocation policies in different parts of the world. The definition of the ITU Regions is based largely on longitude. According to ITU Radio Regulations section 5.1: Member States assign licenses to stations; article 5 of the ITU regulations allocates frequencies to services (such as broadcasting and mobile). The ITU divides the world into five administrative regions:

A the Americas,

B Western Europe,

C Eastern Europe and Northern Asia,

D Africa, and

E Asia and Australasia.

The ITU also categorises states into three Radio regulatory Regions:

Region 1

Europe, Middle East, Africa, the former Soviet Union, including Siberia; and Mongolia;

Region 2

North and South America and Pacific (East of the International Date Line);

Region 3

Asia, Australia and the Pacific Rim (West of the International Date Line).

Thus, the RF allocations fundamentally differ between continents. Longitude may traverse continents, for example, the 40°E meridian crosses Europe (Russia), Asia (Middle East) and Africa.