IEEE recently announced the publication of the 802.22™ standard which aims to provide broadband access to wide regional areas around the world and bring reliable and secure high-speed communications to under-served and un-served communities.
This new standard stands for Wireless Regional Area Networks (WRANs) and takes advantage of the favorable transmission characteristics of the VHF and UHF TV bands to provide broadband wireless access over a large area up to 100 km from the transmitter. Each WRAN will deliver up to 22 Mbps per channel without interfering with reception of existing TV broadcast stations, using the so-called white spaces between the occupied TV channels. This technology is especially useful for serving less densely populated areas, such as rural areas, and developing countries where most vacant TV channels can be found.
IEEE 802.22 incorporates advanced cognitive radio capabilities including dynamic spectrum access, incumbent database access, accurate geo-location techniques, spectrum sensing,regulatory domain dependent policies, spectrum etiquette, and coexistence for optimal use of the available spectrum.
There are several development scenarios for WRAN. As an extension of 802.16 (WiMAX) standard, the 802.22 is an ideal solution for offering rural broadband access. Being linked to 802.11 works, WRAN targets WiFi as well (this solution is known as Super Wifi). But it can also be used as a cellular extension to allow mobile telecommunication operators to improve coverage and/or capacity of their networks by using white space spectrum. Another scenario forecasts M2M, smart grid and smart metering solutions (as an extension of 802.15 standard).
Most of the research work and implementation today concerns band identification throughdatabases queries. The developed white space databases (WSDB) provide available channels in TV white space to white space base station (WSBS) by responding to WSBS's query. The interface between existing TV broadcasting and the secondary system is automatically calculated and available channels at each WSBS location are derived.
Regulation conditions vary across countries. FCC adopted rules for unlicensed use of television white spaces in 2008. OFCOM followed in 2009 with the digital dividend decision. In the same year Denmark decided to allow the use of MUX7 for other than TV purposes. In 2010, the Australian Federal Government announced that the digital dividend would be a contiguous 126 MHz from 694 to 820 MHz with new networks to operate in 2012. Finally, the ECC reports 159 technical and operational requirements for the possible operation of cognitive radio systems in the white spaces offrequency band 470-790 MHz.
One thing is sure: harmonization is needed to create a real market.
During the White Space Summit, to be held in Novotel Paris Roissy CDG , from 10 to 12 December, 2013, experts will address all technical and standardization issues that still need to be solved.
