(Adds further details, CEO quote)
By Aditi Shah
NEW DELHI, July 10 (Reuters) - India's top phone carrier Bharti Airtel Ltd plans to invest 20 billion rupees ($310 million) over three years on a programme to improve customer experience, as it pushes back against new rival Reliance Jio that has disrupted world's second-biggest mobile phone market by customers.
As part of the programme, dubbed Project Next, Bharti Airtel will redesign its 2,500 retail stores, revamp its mobile application, and allow its contract mobile phone subscribers consume unused data in the next billing month.
"Over the course of the next 18-24 months you will see a lot more initiatives under Project Next as we transform ourselves into being a fully digital service provider," Gopal Vittal, Bharti Airtel's Chief Executive for India and South Asia, told a news conference.
Reliance Jio Infocomm Ltd, the telecom startup backed by India's richest man Mukesh Ambani, disrupted the country's highly-competitive telecoms sector as it launched late last year with cut-price data and free voice plans.
That has hurt revenue and profits at the incumbent carriers led by Bharti Airtel and Vodafone Group Plc's Indian unit who have responded with a string of price cuts to retain customers.
The industry saw its revenue for the January-March quarter falling more than 15 percent from a year earlier to 408.31 billion rupees hurt by intense competition and price cuts, local ratings agency CARE estimated based on data from the sector regulator.
More than 95 percent of India's billion-plus mobile phone subscribers use so-called pre-paid connections, where customers pay upfront for services and tend to switch carriers. Postpaid, or contract, customers are stickier, and the average revenue per user for the carriers is also higher.
From August, Bharti Airtel will allow its postpaid customers to carry forward up to 200 gigabytes of unused data to the next cycle, Vittal said.
Among other measures, Bharti Airtel will also offer customers a smartphone damage protection plan, he said. ($1 = 64.5425 Indian rupees) (Reporting by Aditi Shah; Writing by Sankalp Phartiyal; Editing by Devidutta Tripathy and Louise Heavens)