At present, almost all the bandwidth on India’s 15 satellites are presently in the broadcasting oriented bands of C and Ku, and are used for direct to home and other broadcasting purposes. A limited amount of spectrum is used by ATMs and OB vans.
Marking a change, in June this year, the Indian Space Research Organization or ISRO launched the GSAT-19 satellite, the first one with a Ka band transponder.
Unlike C-band (3.7 GHz to 6.5 GHz) and Ku band (11.7 – 14.5 GHz), Ka band (26.5–40) is not usually used for broadcasting services such as DTH as the beams can be easily cut off by clouds.
Instead, it is used for providing non-critical broadband coverage, especially in areas where cloud coverage is thin, such as central and western India.
India has not focused on the satellite broadband so far because of the extreme demand from the broadcasting industry.
With most broadcasters having found decent amounts of capacity, it is now focusing on broadband application, including on hand-held devices.
“Next year beginning, we are going to have GSAT 20 and following, GSAT 29, which will give us almost 100 Gbps capacity,” he said.
100 GBPS means 1 lakh individual connections of 1 Mbps.
This will be used to connect remote areas still untouched by the Internet because of the challenges involved in taking telecom connectivity to the places.
Besides this, satellite broadband will also come in hand for providing Internet service for those on the move.
It can even be used to provide backhaul connectivity to remote 4G telecom towers which cannot be connected using fiber.
A single satellite being launched early next year alone will add 16 Gbps to India’s total satellite broadband capacity, Kumar added.
This is being achieved by not just tapping into the Ka band, but also going even higher to the Q/V bands.
Another strategy being used is to restrict the size of satellite beam so that it doesn’t spread over the entire country, but can be confined to a few districts. This allows the same frequency to be reused for another beam that is focused on other districts.
At present, said Kumar, the highest number of beams over India from a single satellite is eight. “Early next year, we will have a satellite with 16-beams and two polarizations, giving a 32-beam system capable of providing up to 16 Gbps of capacity,” he said.
The second big advancement will be in reducing the size of receiving equipment.
At present, satellite dishes used for the purpose — such as those on top of ATMs — are a few feet in size. This makes such systems difficult to be used by expedition teams and others on foot.
Kumar said the size of the receiving equipment can be reduced if one increases the size of the transmitting antenna on the satellite.
“One satellite going up later this year will have a six-meter antenna and we are working on a 12-meter diameter antenna so that it is possible for us to carry small handheld devices and get the broadband signals anywhere in the country,” he said.
Finally, said Kumar, ISRO is also starting experiments on low-earth satellites. Traditional satellites are placed at a distance of about 42,000 km from the earth’s surface, while low-earth satellites are placed within a few hundred km.
This, said Kumar, will make satellite communications faster and reduce the delay that can be seen in TV broadcasts, where an anchor speaks to a guest in a remote location.