White-Space Wi-Fi 802.11af

May 11, 2017 at 8:00 AM


Waste not, want not, seems to be a growing way of life for many people these days, and that theme will soon apply to the Wi-Fi spectrum as well. The IEEE standard 802.11af, also known as white-space Wi-Fi or White-Fi, will utilize the unused space in the TV spectrum, the TV white-space, to support Wi-Fi networks.


How is this possible?


Broadcast television coverage is organized to leave a certain amount of space between coverage areas to avoid interference. This results in a significant amount of space where channels are unused. 802.11af allows Wi-Fi applications that require less power to utilize the white-space between coverage areas without causing interference.


Why do we need White Space Wi-Fi?


The need for more spectrum is greater than ever. 802.11af fulfills this need by allowing wireless networks to take advantage of the white-space in the frequency spectrum. 802.11af provides support for operation in unused TV channels in the VHF and UHF bands, which adds white-space services to 802.11 WLAN devices and builds upon the 802.11ac offerings.


What are the benefits?


In addition to providing more spectrum for Wi-Fi use, 802.11af allows for long-range and low-power operation because it uses frequencies below 1 GHz. This means it will work more like a traditional Wi-Fi network to increase bandwidth over a long-range wireless local-area network (WLAN).


The lowest band used by current Wi-Fi systems is 2.4 GHz. 802.11af operates in the 6, 7 and 8 MHz channels, which makes it backward compatible with existing international TV band allocations.


Operation can be arranged for 1-4 channels, either contiguously or in two non-contiguous blocks, allowing devices to collect enough spectrum to achieve high data rates. Plus, there is a possibility that additional unused frequencies can be accessed to add even more capabilities.


Here is a chart showing the 802.11af frequencies and corresponding TV white-space channels:




White-space Wi-Fi 802.11af is not going to be the perfect solution for all applications. But it is going take processing technology to another level by providing access to more spectrum to meet today’s ever-growing Wi-Fi needs.


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