Editing Orthogonal frequency-division multiplexing (section)

==== COFDM vs VSB ====

The question of the relative technical merits of COFDM versus [[8VSB]] for terrestrial [[digital television]] has been a subject of some controversy, especially between European and North American technologists and regulators. The [[United States]] has rejected several proposals to adopt the COFDM-based [[DVB-T]] system for its digital television services, and for many years has opted to use [[8VSB]] ([[vestigial sideband modulation]]) exclusively for terrestrial digital television.<ref>{{Cite web|last=Lung|first=Doug|date=2001-01-01|title=8-VSB vs. COFDM: The Debate Continues|url=https://www.tvtechnology.com/opinions/8vsb-vs-cofdm-the-debate-continues|access-date=2021-11-18|website=TVTechnology|language=en}}</ref> However, in November 2017, the [[Federal Communications Commission|FCC]] approved a voluntary transition to [[ATSC 3.0]], a new broadcast standard which is based on COFDM. Unlike the first digital television transition in America, TV stations will not be assigned separate frequencies to transmit ATSC 3.0 and are not required to switch to ATSC 3.0 by any deadline. Televisions sold in the U.S. are also not required to include ATSC 3.0 tuning capabilities. Full-powered television stations are permitted to make the switch to ATSC 3.0, as long as they continue to make their main channel available through a simulcast agreement with another in-market station (with a similar coverage area) through at least November 2022.<ref>{{cite web |title=Report and Order and Further Notice of Proposed Rulemaking |url=https://docs.fcc.gov/public/attachments/FCC-17-158A1.docx |website=Federal Communications Commission |access-date=8 March 2021 |archive-url=https://web.archive.org/web/20201018191123/https://docs.fcc.gov/public/attachments/FCC-17-158A1.docx |archive-date=18 October 2020 |date=20 November 2017}}</ref>

One of the major benefits provided by COFDM is in rendering radio broadcasts relatively immune to [[multipath interference|multipath]] distortion and signal [[fading]] due to atmospheric conditions or passing aircraft. Proponents of COFDM argue it resists multipath far better than 8VSB. Early 8VSB [[digital television|DTV]] (digital television) receivers often had difficulty receiving a signal. Also, COFDM allows [[single-frequency network]]s, which is not possible with 8VSB.

However, newer 8VSB receivers are far better at dealing with multipath, hence the difference in performance may diminish with advances in equalizer design.<ref>{{Cite web|last=TVTechnology|date=2008-04-11|title=Distortions and 8-VSB|url=https://www.tvtechnology.com/news/distortions-and-8vsb|access-date=2021-11-18|website=TVTechnology|language=en}}</ref>