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BBNL & BharatNet

Bharat Broadband Network Limited (BBNL) is leading Government of India’s flagship BharatNet project, connecting all the Gram Panchayats of the country by laying of optical fiber (primarily) beyond the Block up to the Gram Panchayats. The satellite technology has evolved over the years. The present high-throughput satellites (HTS), with multiple beams (with more downlink power per beam), are capable of providing terabits of data throughput. The beams can be steered over a particular geographical location to provide more data bandwidth over that area. ISRO has launched high-throughput multi-beam, geo-stationary satellites (GSAT-19, GSAT-11, GSAT 29) in the last 2–3 years, which are capable of providing data throughput of about 30 Gbps capacity over India. Handheld satellite phones are available, which are capable of providing telecommunication services at each and every corner of Earth, i.e., across oceans, poles, forests, Himalayas (including Mount Everest), and on the ships and aircraft.

The price of data BW has also come down 4–5 times from about `9 lakh per Mbps per annum to about 2.11 lakh per Mbps per annum.

The digital infrastructure of the middle mile, thus created, is made available to the service providers (TSP/ISP/MSO/LCOs) at a nominal price, who in turn use it to provide affordable high-speed broadband to rural citizens and institutions. The objective is social inclusion, through effective delivery of government schemes and citizen-centric services, using broadband, e-governance, e-education, tele-medicine, e-banking, etc. It is expected that the affordable broadband access will unleash plethora of opportunities in the rural hinterland, which still houses more than two-thirds of the country’s workforce but contributes less than half the national income.

Keeping in mind the enormous future requirement of bandwidth, BharatNet prefers to use optical fiber cable (OFC) as medium of connectivity, but other media, such as radio and satellite, are also being used to connect remote, inaccessible locations where OFC laying is either not possible or economically not viable.

Satellite-based technologies are being used across the world for various purposes like telecommunication, TV/DTH/broadcast, earth imaging/photography/weather forecasting/navigation (GPS)/data collection/disaster management/security monitoring, etc.

The earlier satellites were geo-stationary (located at about 36,000 km above the equator), with a single beam covering large geographical area, and were suitable for voice services but had low data throughput capacity (a few kilobits).

Under BharatNet, approximately 7000 sites are planned to be connected through satellite across 26 Indian states and UTs. Most of these sites are in the North-Eastern Region, J&K, Ladakh, HP, Uttarakhand, Sikkim, Islands, LWE areas like Chattisgarh, Odisha, Jharkhand, and other states through the satellite beam available in the region. As of now, more than 4000 sites have been commissioned using satellite.

The network has VSATs (1.2 dia antenna) at GP sites connected in a star topology to four satellite gateways (9.1 dia antenna) at Ranchi, Ahmedabad, Delhi, and Bengaluru, through satellite beams available in the region. The baseband equipment of gateways and the VSAT equipment use the latest technology DVB – S2X, which is most suitable for digital broadband type of services.

The satellites are ISRO’s high-throughput satellites GSAT-11 and GSAT-19. The satellites operate in Ka * Ku frequency bands, i.e., the transmission from and to the gateways is in Ka frequency band, and the transmission from and to remote GP site (VSAT) is in Ku frequency bands.

One such constellation of satellites located at medium earth orbits (MEOs) at about 8000–12,000 km over earth, provides higher data throughput with low latency (about 150 ms). Another large constellation of satellites (thousands) at lower earth orbit (LEOs) at about 1000–2000 km above earth, is also being launched, which is capable of providing much higher throughputs with very low latency (less than 50 ms), and thus are comparable with optical fiber. MEOs are already available for commercial usage and LEOs are likely to be available for commercial usage from the year 2022 onwards.

The price of the data bandwidth provided through satellites has also come down drastically and is comparable with cellular mobile communication networks for the end users.

In future, the combination of geo-stationary satellites, MEOs and LEOs shall be used, depending upon the application/usage.

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