TV White Space Communications is the most preferred wireless alternative for long distance communication. TV White Spaces technology utilises the unused “white space” to provide cheap Internet connectivity to remote areas. “white space” refers to gaps of unused spectrum between terrestrial broadcast channels in the 470-700MHz (TV-UHF) band. The gaps are necessary since TV signals are transmitted at high power and would otherwise interfere with each other.
Relevance for India
In India large bands of frequencies (470 MHz – 698 MHz) are allocated for TV transmission but since very few terrestrial TV broadcasting stations are there, large chunks of spectrum are available in this band which can be used for licensed or un-licensed use to increase broadband penetration. Apart from these, there are protective bands of unused spectrum (white space) between bands occupied by TV signals which originally serve the purpose of preventing interference. These guard bands in future will not be needed with the newer digital technology replacing older analog TV signals. Unlike Wi-Fi, which has a range of only about 100 metres, the TVWS uses the lower frequencies white space signals to reach up to 10 km. A single base station can reach households that are as far away as 10km – 30km depending on antenna height. A single 8 MHz channel can provide a data rate of 30 Mbps, which can be shared by about 15 users (2 Mbps bandwidth per user) simultaneously. As the number of users increase, additional base stations with directional antennas can be used or more frequencies can be assigned.
Advantages
- It is cost-effective technology to provide broadband service in rural India. Lower infrastructure cost and higher coverage will balance the low financial returns in rural areas of India and will attract vendors to provide services in rural areas
- When compared to Wi-Fi, it can provide the connectivity up to 10km.
- It will reduce the burden on the already overcrowded spectrum bands to provide broadband connectivity
Challenges
- As technology is new it will take time for adaption. Creation of awareness is necessary.
- Development of white space devices in a large scale.
- Creation of regulatory framework for auction of spectrum. Broadband India Forum (BIF) has urged the telecome ministry to auction the spectrum available in TV UHF band and it should not be given away free. Auction of the spectrum require huge investment and it may become hurdle in the development of the technology.
Role in Digital India
Success of Digital India initiative depends on the expansion of the internet connectivity. Less than 10% of Indians have access to broadband and barely 20% can access the internet. The existing National Optical Fibre Network (NOFN) is already overcrowded to provide the internet connectivity on a large scale. There is a need to explore more alternatives to provide affordable and perhaps faster connectivity in remote areas of the country. Tech giants such as Facebook, Google and Microsoft are already making efforts in this direction. While Facebook is developing drones, Google is working on Internet beaming balloons, under a project called Project Loon.
Microsoft, however, has come up with a very interesting idea of ‘White Space Tech’, which uses unused spectrum between two TV channels, to provide free connectivity. Microsoft is also planning to try out the technology in India. The company has already conducted this project on pilot basis in countries such as Ghana, Botswana, Namibia, Tanzania, South Africa, Kenya and Singapore, among others. Presently, Microsoft, DoT, DeitY , ERNET and government of Andhra Pradesh have started a pilot test of white space technology with four educational institutions in the district of Srikakulam, Andhra Pradesh with Z. P. High School at Voppangi as the base station, the other three campuses as receivers, located at a distances of 10 kilometres or more from the base station.