NEW DELHI: Vodafone’s Indian unit posted a net profit for the second successive year and outpaced its group counterparts to report 12.6 per cent organic growth in revenue through March, as subscribers used more of its premium data services. It also announced plans to roll out 4G services towards the second half of the year.Despite an operationally strong performance, the.`20,000-crore tax arbitration process between the Vodafone Group and India continues to be an overhang. The process may be delayed further with the arbitrator appointed by the government — former Chief Justice of India RC Lahoti — resigning earlier this month.Abdulqawi Ahmed Yusuf, vice-president of the International Court of Justice, who was being proposed as the third arbitrator by Vodafone and India, has also declined to take up the position. Vodafone had named Canadian trial lawyer Yves Fortier as its arbitrator."There’s likely to be a delay in appointing the chairman pending the Indian government appointing a replacement for its party-appointed arbitrator. If there is no subsequent agreement on appointment of a chairman, the International Court of Justice will appoint the third arbitrator," Vodafone said in a statement.While Vodafone India continues its operational growth, led by data, the company, like its peers such as Bharti Airtel and Idea Cellular, continued to face pressure on its voice business, thanks to competition in some circles. Newly appointed managing director and chief executive officer Sunil Sood said that there was room to increase tariffs, mainly for voice services, by reducing discounts, but said the company won’t change headline tariffs, given the competitive landscape of the telecom sector.Sood added that the company is undertaking 4G trials before rolling out the premium data services, directed at high-end data users, in the "latter half of this year". Vodafone has 4G spectrum in the 1800 Mhz band in five circles. "We will learn from the trials and then expand."He further said that going forward the government should give longterm clarity on the amount of spectrum and the kind of spectrum to be auctioned, besides clarity on issues such as merger and acquisition norms, spectrum sharing and trading guidelines.The Vodafone Group added fresh equity of Rs 6,000 crore in the local operations in March 2015, most of which will be used for expansion over FY 2016.Service revenue for the year ended March rose toRs 42,352 crore, with data contributing to 15 per cent of the total at Rs 5,690 crore, up from 10 per cent a year ago. While voice average revenue per minute (ARPM) reduced by 0.45 per cent to 37.3 paise for FY 2015 compared with the year before, overall ARPM increased 6.5 per cent over last year to 50 paise a minute. Average revenue per user (ARPU) increased 1.69 per cent over last year to Rs 202.For the quarter ended March 2015, service revenue increased by 12.1 per cent on-year to Rs 10,887 crore from Rs 9,713 crore the year before. Overall, ARPM was 50 paise and voice RAPM was 36.1 paise while APRU was Rs 200.Data revenue was up 65.5 per cent on-year with 63.8 million customers using this facility. Of this, 19.4 million customers use 3G data. "Vodafone India has become the largest company in the Vodafone Group by data traffic, beating European countries like Germany," Sood said.He attributed a large part of 3G revenue growth of 140 per cent on-year to OTT players such as Whatsapp and Facebook, and supported them in the net neutrality debate. "We’re pro net neutrality. We’re pro OTT and apps. But we’re also pro-net equality -- there should be no discrimination between those offering same services. If we’re subjected to licensing, the rule should be applied to all (offering voice services)," Sood said.On the issue of zero-rating, Sood said that it was only a ‘price plan’ and a ‘trivial matter,’ with rules on the same yet to come. "Let there be a debate and let the government decide the rules. We’re waiting for the rules. We don’t have such a plan (zero-rating) in place, nor do we have any plans (of introducing one)."At the current rate, the India unit contributes over 10 per cent to the parent's service revenue which rose 9.4 per cent to £38.5 billion. The company is ranked No. 2 in India, with 183.8 million subscribers, which is the most Vodafone Group has in any country.In March, Vodafone won spectrum in 12 telecom circles for a total cost of nearly Rs 26,000 crore, including airwaves in all six of its 900 MHz circles due for extension in December 2015.