Digital dividend after digital television transition
Spectrum freed by the analog-to-digital television transition.
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The digital dividend refers to the radio spectrum released during the transition from analog to digital television. Because digital television requires less spectrum than analog—due to lossy compression, the ability to transmit multiple digital subchannels in the same bandwidth, and reduced need for guard bands—the freed-up spectrum can be repacked and allocated for other wireless services. This spectrum typically lies in the VHF band (174–230 MHz) and UHF band (470–862 MHz), with a midpoint at 666 MHz, though its exact location and size vary by country based on factors such as geographical position and penetration of satellite or cable services.
Quick Facts
- Midpoint frequency
- 666 MHz
- U.s. transition completion date
- 12 June 2009
Facts from the source article.
Lore & Background
The digital dividend arises because digital television transmissions are far less prone to RF interference from adjacent channels than analog signals, eliminating the need for empty guard channels. This allows broadcasters to be repacked into fewer channels, leaving more contiguous spectrum for other uses. The transition is not simultaneous worldwide; the United States completed its transition on 12 June 2009 and auctioned the spectrum, while Australia was still planning for it. The location and size of the dividend differ among countries due to geographical position and the penetration of satellite and cable services.
In 2007, the World Radiocommunication Conference revised the allocation of a portion of UHF spectrum for mobile broadband and advanced mobile services, setting a framework but allowing member countries to consider national requirements. For example, countries in global regions one and three (Europe, the Middle East, Africa, Russia, Asia, and Australia) use the 790–960 MHz band for international mobile telecommunications (IMT). Some countries in region three (Bangladesh, China, Korea, India, Japan, New Zealand, Papua New Guinea, Philippines, and Singapore) identified the 698–790 MHz band for IMT, while region two (the Americas) planned the 698–960 MHz band for IMT, though 806–960 MHz was already used for mobile telecommunications there.
Proposed uses for the digital dividend include digital terrestrial TV, advanced mobile services, broadcast mobile TV, commercial wireless broadband (both fixed and mobile), wireless broadband for public safety and disaster relief (PPDR), and services ancillary to broadcasting and programming (SAB/SAP). Many countries favor using part of the dividend, particularly the upper UHF band (790–862 MHz), for electronic communications services such as mobile communications and wireless broadband.
Reader's Guide
The digital dividend is significant because the UHF spectrum it releases can carry signals over long distances, penetrate buildings, and carry large amounts of data, making it valuable for mobile broadband and other services. Experts note that using this spectrum for mobile broadband is cheaper than fixed broadband for last-mile connectivity, potentially facilitating economic development: a McKinsey report suggested that every 10% increase in household broadband penetration brings a 1.4% increase in GDP growth, which often leads to job creation. Mobile broadband can also serve rural and low-income populations, providing medical, educational, and general information.
Some researchers argue the digital dividend offers an opportunity to bridge the digital divide, as the spectrum's characteristics require fewer base stations to cover a given area, reducing the cost of providing broadband in remote rural areas where fixed-line infrastructure is not profitable. However, others disagree, contending that the trade-off between reach and speed significantly limits scalability; if transmission demands grow at current rates, a wireless broadband network covering large areas may become outdated before deployment, so the digital divide would persist.
The U.S. 700 MHz auction (Auction 73) demonstrated the spectrum's value, raising over $19 billion. The auction included blocks with specific conditions: Block C (22 MHz) had open-access provisions requiring the winner to allow any safe device on the network and to make their own networked devices open. Block D (10 MHz) required the winner to participate in a Public Safety/Private Partnership, meeting public safety specifications for coverage and redundancy, and allowed commercial traffic on the public safety portion when not in use. Blocks A, B, and E (30 MHz total) were licensed for small geographic areas, intended for regional or rural telecommunications.
Frequently Asked Questions
What is the digital dividend in radio spectrum?
The digital dividend is the chunk of radio spectrum that becomes available once a country finishes switching from analog to digital television broadcasting. Because digital TV packs more content into less bandwidth, the leftover frequencies can be reassigned to other wireless uses.
Why does digital television free up more spectrum than analog did?
Digital TV relies on lossy compression, can multiplex several subchannels within the same channel width, and needs smaller guard bands between channels. Together these efficiencies mean the same programming footprint occupies a narrower slice of the spectrum, leaving the rest open for repacking.
Which frequency bands does the digital dividend typically occupy?
The freed spectrum generally falls in the VHF range (174–230 MHz) and the UHF range (470–862 MHz), with 666 MHz often cited as a midpoint reference. The exact size and location shift from country to country depending on geography, existing allocations, and regulatory choices.
When did the United States complete its analog-to-digital TV transition?
The U.S. finished its nationwide digital television switchover on 12 June 2009. That date marked the point at which the freed spectrum could be formally auctioned and reallocated to new wireless services.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Digital dividend after digital television transition (CC BY-SA 4.0).
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