NEW DELHI: Bharti Airtel is set to take on bitter rival Reliance Jio Infocomm at its own game by launching, as early as next week, voice services using the same 4G technology employed by the industry newcomer, people familiar with the matter said. The services will be expanded across India well within this fiscal year, they said.The Voice over LTE VoLTE ) technology offers more clarity on voice through high definition calling, using the same network used for carrying data. The Sunil Mittal-owned market leader is the first of the established telecom carriers to adopt the technology, and it is expected to take the competition to the Mukesh Ambani-owned new entrant that has highlighted free VoLTE calls and unlimited data as USPs to garner a 130-million user base within a year of its commercial launch last September.Airtel is likely to launch its VoLTE services first in Mumbai, followed by Kolkata and other metro cities, the people said. The company had conducted trials in the metros and three to four other major cities for a few months.“Some customers in Mumbai and Kolkata, and then other metro cities where Airtel is planning to launch, will get messages to activate VoLTE calls on their phones,” one of the people said.“They (Airtel) will expand to more cities and cover the entire country well before this financial year end (on March 31),” said another person who knows about the company’s plans. Bharti Airtel declined to comment.Jio is currently the only operator offering VoLTE and has been touting that service as a key differentiator with its rivals. Idea managing director Himanshu Kapania had in May said that the No. 3 telco had finished testing of its VoLTE network and was expected to launch the services by September. The company has not commented further on the launch plans.Through its own VoLTE services, Airtel is taking another step to try and ring-fence its subscriber base amid a fierce price war for the market share, analysts said.Sandeep Das, a senior adviser at Analysys Mason, said Airtel launching VoLTE services would be a great consumer move, as it would help it retain existing customers and sign up new ones, besides bringing a sea change in call quality which has not happened for years.Older operators including Airtel currently offer voice services on the legacy circuit-switch technology, with data being offered on a 4G network and voice on a 3G or 2G network. VoLTE technology allows an operator to offer both voice and data on the same network with voice being just another application that rides on an LTE data network, which thus means more efficient use of airwaves.“This means if both voice and data can be offered on VoLTE, the 3G or the 2G network as the case may be is freed up and can be refarmed for offering 4G data services,” one of the people said. This, the person said, would give the telco more airwaves to meet surging demand for mobile broadband.Airtel has already conducted final trials with nearly 15 models of devices, the people said. Software patches will be issued to enable user devices to be compatible with Airtel’s VoLTE calls, they added.About one in every three phones sold in the April-June quarter in India was a VoLTE device, and this share could double by the end of the second quarter of 2018, Counterpoint Research said. According to the firm, close to 200 million 4G VoLTE featurephones could be sold in India in the next five years, providing a major opportunity for carriers to offer their services and handset makers to bring in new customers.Reliance Industries is set to ship its VoLTE featurephone, JioPhone, starting this month for a refundable threeyear deposit of Rs 1,500. It got bookings for 6 million units in a day and half when it took orders. Indian phone makers such as Intex and Lava are also expected to launch similar models, thus creating a critical mass of low-cost VoLTE-ready phones. Airtel could benefit from the creation of a large ecosystem of VoLTE-based devices.