* Consolidated net profit at 7.21 bln rupees vs 7.46 bln estimate
* Revenue rises 17 pct, one-off gain aids revenue and profit
* Risk remains on regulatory fees, spectrum reallocation
* Bharti is worst performer on benchmark index this year (Adds details, comments from analyst, company, graphic link)
By Devidutta Tripathy and Aradhana Aravindan
NEW DELHI/MUMBAI, Nov 7 (Reuters) - Top Indian telecommunications carrier Bharti Airtel Ltd will struggle to improve its profits in the coming quarters amid an uncertain regulatory environment in its home market after the company reported its 11th consecutive quarter of profit decline with margins pressured by intense competition.
Bharti, controlled by billionaire Sunil Mittal, on Wednesday reported its consolidated net profit fell 30 percent from a year earlier to 7.21 billion rupees ($132.5 million) for the three months to September, despite a one-off gain of 2.39 billion rupees from an outstanding dispute over inter-connect charges.
Competition is seen abating in the world's second-biggest mobile phone market after a court order revoked the permits of several smaller carriers, which is a positive for market leaders Bharti and the local unit of Vodafone Group Plc.
India's leading carriers, however, face the risk of paying out billions of dollars in regulatory fees over the next few years with the government planning to impose a surcharge on airwaves held by them and also due to reallocation, or switching, of their superior quality spectrum when their permits are renewed.
"The worry remains regulation," said Vivekanand Subbaraman, a telecommunications analyst at PhillipCapital India. "The regulatory concerns have overshadowed operating performance," he said, adding Bharti could continue to see its margins eroding.
India is planning to levy more than $5.5 billion in surcharges on airwaves held by older telecommunications companies, from which Bharti's payout is estimated to be just under $1 billion.
There is also a plan to replace superior quality airwaves of companies, including Bharti, with relatively inferior quality airwaves when their permits are renewed starting in late 2014, which will significantly push up the carriers' capital expenditure apart from paying for the replacement airwaves.
Rising costs of airwaves should mean an increase in call tariffs, but a highly competitive market has forced companies to keep call prices low. Bharti raised call prices by about a fifth last year, but was later forced to pare the increase in some zones as it lost market share to competition.
"With consolidation happening, I think tariffs will have to correct (increase)," Sanjay Kapoor, chief executive for Bharti's India and South Asia operations, told a news conference after the results were released. "(But) you cannot go and raise prices in isolation."
Revenue from voice calls accounts for about 85 percent of Indian carriers' revenue, with mobile data still at a nascent stage. Operators launched high-speed 3G networks last year, but less than 5 percent of the more than 900 million customers have subscribed to the premium services.
"We're starting to see traction in data," said Sarvjit Dhillon, group chief financial officer at Bharti Airtel's parent company. Bharti's mobile data business grew 77 percent during the September quarter from a year earlier, it said.
Shares in Bharti, valued at about $19 billion, were down more than 1 percent by 0651 GMT in a positive Mumbai market. The stock is down more than a fifth this year to be the worst performer among the components of the benchmark index.
Bharti, nearly a third owned by Southeast Asia's top phone carrier Singapore Telecommunications Ltd, said revenue for the September quarter rose 17.4 percent from a year earlier to 202.7 billion rupees.
Analysts had expected net profit of 7.46 billion rupees on revenue of 196.02 billion rupees, according to Thomson Reuters I/B/E/S.
Bharti in 2010 ventured into Africa at a time when growth in its home market had started showing signs of saturation. The company, which bought money-losing operations in 15 African countries for $9 billion, has yet to turn a profit there.
Losses in its Africa operations widened to 5.39 billion rupees from 4.27 billion rupees a year earlier. But operating margins in Africa improved to 27.1 percent from 26.4 percent a year earlier. For its India and South Asia operations, margins dropped to 32.7 percent from 36.1 percent a year earlier.
Monthly average revenue per user, a key metric for telecommunications carriers, fell 4 percent from the previous quarter to 177 rupees for its Indian operations. In Africa, ARPU fell 2 percent sequentially to $6.4.
$1 = 54.4350 Indian rupees Editing by Matt Driskill