TV white spaces for inexpensive broadband?

Due to potential interference, the TV band usually has unused spectrum inbetween any two stations which seems a waste of valuable spectrum that could be utilised to provide broadband connectivity, particularly in rural areas.

In July 2011 the IEEE accepted the IEEE 802.22 standard which is aimed at using cognitive radio (CR) techniques to allow sharing of geographically unused spectrum allocated to the television broadcasting services on a non-interference basis. It provides an opportunity to bring broadband access to low density populated rural areas. “I believe this is very relevant for South Africa,” said Christopher Geerdts, chairman of the Wireless Access Providers’ Association (WAPA).

WAPA, established in 2006, is a non-profit industry representative body acting as a collective voice for independent wireless operators in South Africa. The association’s primary objective is to ensure the sustainability of the wireless access services market. WAPA facilitates self-regulation of the outdoor fixed wireless and indoor nomadic wireless industries and seeks to minimise the potential of users of licence-exempt bands causing interference to services provided to licensed as well as unlicensed users.

Typical members are SMME providing extensive coverage in rural areas where there is no cost-effective alternative access means. Free or E-rated internet services, including the underlying ECNS service, are provided to a large number of schools and other social responsibility programmes, in rural and previously disadvantaged areas which are not serviced by the incumbent operators.

The non-protection of users in the licence exempt bands is a globally accepted policy and thereby increases the responsibilities of spectrum users to share spectrum efficiently and manage interference in a cooperative manner.

WAPA is also positioned to be an interface between the regulator (ICASA), network operators, service providers and consumers. Membership is differentiated from other wireless providers by their focus on using open standard wireless technologies (WiFi). WAPA offers its members regulatory advice, a code of conduct, an enforcement process and a forum for sharing knowledge and resolving technical problems.

The Institute of Electrical and Electronics Engineers (IEEE) and the US Federal Communications Commission pursued a centralised approach to identify spectrum that could be used to provide broadband services. Specifically base stations would be equipped with GPS receivers to report their position. This information would be sent back to a central server which would respond with information about available free TV channels and guard bands in the area of the base station. Other proposals considered are for local spectrum sensing where the base station would decide by itself which channels are available for communication.

At a workshop arranged last year by WAPA, Dumisa Ngwenya, at the time head of the Independent Communications Authority of South Africa (ICASA)’s engineering division, said that ICASA signed memoranda of understanding (MoU) with two local universities and the CSIR Meraka Institute to study unused spectrum and the design and production of devices that could be used for Wi-Fi. “The MoU with Meraka Institute and the two local universities will ensure that South Africa’s policy is well-informed and that pilot studies and research and development could take place concurrently.”

The discussion at the WAPA workshop revolved around licensing and whether the spectrum should be free, whether there would be interference, and the benefit to the economy. The broadcasters are uneasy with the usage of white spaces because it is not yet clear how the allocation will be done and whether it will interfere with services. A pilot study conducted in the United Kingdom has however shown that the application of white spaces for communication service is feasible.

Google is keen to invest in and support South African companies that want to pilot wireless broadband networks using the radio frequency spectrum. Google’s Neil Ahlsten said that white spaces are a hot topic in the telecoms world. Regulators in the US and Europe are supporting the call to use white spaces to provide broadband services and see it as a way forward in solving the much vaunted “bridging the digital divide” – turning talk into long awaited action!

“We are actively lobbying ICASA to support a few pilot studies to allow us to prove that it can work,” said Geerdts. “WAPA members are already providing valuable broadband services in areas that are generally overlooked by the big companies. With access to white spaces WAPA members will make a huge contribution for government to achieve its 2020 broadband for all vision.”

Currently the Tertiary Education and Research Network of South Africa is planning a pilot study in Cape Town to connect some 20 schools. There are still some legalities to be finalised but the study is expected to commence soon.

Source: EngineerIT

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TV white spaces for inexpensive broadband?