DoT’s modified orders prompts Reliance Jio to shift out of GMRT’s protected bandwidth

Reliance Jio Infocomm Limited (RJIL) has commenced the process of ‘switching’ to the 1800 MegaHertz (MHz) frequency band in the Junnar region of Pune district, where its operations in the 850 MHz band in the last few years were causing significant signal interference to the operations of the Giant Metrewave Radio Telescope (GMRT).

This comes after the Department of Telecommunication (DoT) finally issued ‘corrected’ spectrum allocation orders in January this year, in which the RJIL has now been allocated the spectrum in the 1800 MHz band. Simultaneously, the order has asked the telecom to cease all its operations in the DoT’s earlier allocated 850 MHz band in Junnar, as this overlaps with the GMRT’s operating frequency range.

The Indian Express in its report published August 27, 2021, was the first to bring out how signal interference from nearby RJIL’s towers had led to significant data losses and that the matter had remained pending with the DoT. In a subsequent report published on September 28, 2021, the DoT officials updated that the swapping of bandwidths was under consideration.

It took nearly five years for the ministry to issue the said allocation orders since GMRT scientists first flagged the matter in 2017 about the growing transmissions of RJIL in the 850 MHz band. But with no action taken in this period, the GMRT — a one-of-its-kind observatory tracking the faintest and weakest radio signals originating from distant celestial bodies and used by astronomers across the world — suffered irreparable loss in its data quality.

The root cause of the problem lay in DoT’s spectrum auction of 2016 followed by the spectrum allocation. Back then, the telecom ministry erroneously awarded the 800 MHz-900 MHz spectrum range to RJIL in Maharashtra. This included regions around the GMRT — the world’s largest radio telescope operating in low frequency since 2000. Technically, the band around 850 MHz cannot be allocated to any telecom company for signal transmission around GMRT, which is a project under the Department of Atomic Energy and operated by TIFR’s National Centre for Radio Astrophysics (NCRA) Pune. GMRT enjoys a default protection from all kinds of signal interference from the immediate vicinity in its mandate of doing frontline science.

A fortnight ago, the RJIL’s work for shifting the operating frequency commenced. The task of switching tower operations around the GMRT — an array with 30 steerable gigantic antennas located within 25 km of Khodad village — is progressing smoothly.

“We are relieved and thankful that the DoT has finally allocated the correct spectrum in its allocation order. We appreciate the spirit of cooperation and understating shown by the RJIL , which immediately initiated the action to change the frequency of operation from 850 MHz to 1800 MHz for the towers in the GMRT region,” a senior official from NCRA told The Indian Express.

GMRT officials are hopeful that other telecom providers in the region will cooperate and avoid using the 850 MHz band in the GMRT region in the future and allow the observatory to continue functioning to its full potential as an international-class facility.

On the early results since the RJIL’s switch, the NCRA representative said, “The GMRT’s technical team is in touch with the RJIL team to monitor the progress. Our team has reported that the signals are now much more free from interference than earlier.”

In 2019, the GMRT facility underwent its first major upgrade. The upgraded GMRT (uGMRT) is now much more sensitive and able to peer deeper into outer space and handles much more data. It has a capability of ingesting data of up to 40 GB per second and can generate scientific data upto several terabytes per day.