It has also inked a new agreement Bharti Airtel to manage its 2G, 3G, 4G along with other telecom services across 15 circles. The two are already into a  multi-technology deal.
Ericsson also a signed deal with DTH operator Tata Sky for first commercial launch of a 4K broadcast service in India for delivering four times the resolution of standard high definition video.
Under the deal with Idea Cellular, Ericsson will enable Idea Cellular to roll out 3G services in Delhi as well as facilitating upgrade of 5,500 2G network sites.
"We look forward to working closely with Idea to expand its 2G and 3G network rapidly. The new network deployment started in December 2014 and is expected to be completed in 2017," Ericsson India Head of Region Chris Houghton said here without disclosing financial details of the deal.
The new 3G network will be deployed in the 900 MHz band, a band particularly suited to improving app coverage indoors.
Bharti Airtel has extended its existing multi-technology deal with Ericsson for another two years, Houghton said.
"Under the terms of the new agreement, Ericsson will manage 2G, 3G, 4G, Intelligent Network, local and wide area network of Airtel as well has Wi-Fi technologies in 15 circles," he said.
Airtel has pan-India 2G network. It holds 3G spectrum in 13 out of 22 service area in the country  and broadband wireless spectrum across 8 service area which can be used for 4G services.
Ericsson did not disclose service areas where it will manage operations of Airtel and other details.
Under its deal with Tata Sky, Ericsson will provide compression technology for 4K distribution using high resolution format.
"Tata Sky has launched its 4K set top box just ahead of the ongoing cricket World Cup. This will ensure that cricket and sports enthusiasts witness the cricketing extravaganza for the first time in 4K ultra high definition," Houghton said.