The development will boost the service quality of the state-owned telecom major in the region.
"BSNL is investing around Rs 1,500 crore in expanding and improving the existing 2G and 3G network. We expect the expansion to get completed in the next few months," BSNL CGM (Calcutta Telephones) Gautam Chakraborty said.
"Work has already begun and we have received adequate equipment for the setup in our circle," he said.
He said once the project was implemented, service quality and capacity would get a boost in the eastern region of West Bengal, Bihar, Odisha, Jharkhand and the north eastern states.
BSNL was planning to expand GSM lines by over 4 million lines for the region, the contract for which was bagged by Chinese vendor ZTE Telecom India.
BSNL is expanding its capacity by 10 million GSM lines (2G and 3G) to help increase its subscriber base countrywide.
"In Calcutta Telephones network we will install new 300 BTS for 2G and 3G," Chakraborty said.
"We have pockets where network needs to be strengthened and the project will overcome that," he added.
Chakraborty said BSNL was also upgrading its landline network migrating on IP (Internet Protocol) helping the telecom operator to introduce more innovative services.