Under the collaboration, Ericsson and Leonardo will share research and development capabilities and competences spanning from cyber security to 5G networks, the two companies said.
The partnership will also address cyber security while threats are becoming more complex in particular for strategic critical infrastructures, they added.
Major carriers Reliance Industries' Jio Infocomm, Bharti Airtel and Vodafone Idea will conduct the trials along with state-run MTNL in urban, rural and semi-urban areas, the Ministry of Communications said in a statement.
The statement did not mention Huawei and smaller Chinese rival ZTE among the participating network equipment suppliers.
"It's a windfall. We're an overtaxed sector, and now suffering from the crisis," one company source said. "We also ask that auctions' starting prices be lowered, not raised, else they divert resources away from deploying mobile data networks."
One industry source noted that Spain held Europe's third-most costly radio frequency auctions even though the sector's average income has fallen 35% since 2011
The Lumentum deal was followed three weeks later by a $6 billion rival bid from MKS Instruments and an another competing offer from optical components maker II-VI in February worth $6.4 billion.
Earlier this week, II-VI revised its original cash-and-stock offer to raise the cash component, prompting Coherent to call the bid "superior".
KPN expects 3-5% annual growth in dividend and EBITDA after leases of 2.45 billion euros by 2023. The company intends to increase investments in its fibre optic and 5G networks, while cutting costs.