Telecom major Bharti Airtel on Monday said it has upgraded its network infrastructure in Tamil Nadu to ensure better voice clarity and call stability.

The company has further optimised the 3G network, which carries bulk of the voice traffic, by deploying network solutions and advanced software, a press release said here.

The upgradation would in the next six-eight weeks help customers experience improved clarity of voice, call stability and coverage, the release said.

On the data front, there would be increased 4G coverage to enable high-speed data experience for users, it said.

"With improved 4G availability, customers can also opt for Airtel VoLTE which offers high definition voice quality," the release said.

"With the surge in 4G smartphone penetration, we have stepped up our network investments to serve the exploding voice and data usage", it quoted chief executive officer (Tamil Nadu & Kerala) of the company Manoj Murali as saying.

"Airtel has cemented its place as the fastest network in the country and smartphone-users on our network will also enjoy best-in-class voice experience with the latest optimisation", the release said.

Airtel has 23 million customers across the state. Under its 'Project Leap' programme, it plans to roll out 12,000 sites and lay optic fibre cables to a length of 3,000 km, it added.