Telcos could end up paying a heavier penalty for call drops with the telecom regulator reworking the way it assesses the service being provided to about 1 billion cellphone users in India, source said on Thursday.Infrastructure in the world’s second-largest mobile phone market is struggling to keep up with the rising number of users and call-drop continues to be a big headache even after assurances from the Telecom Regulatory Authority of India (Trai) and the government.The Trai would now measure call drops on the basis of data collected on the performance of telecom towers and back-end information from telcos, not from area offices of telecom companies as is the practice.“Report on telecom towers will show the exact amount of activity. This will help us analyse signal strength, call-drop rate and call set-up success rate,” a government official, who did not wish to be named, told Hindustan Times.A service provider is fined Rs 50,000 for not meeting the benchmark of 2% call drops per quarter. The penalty is likely to go up many manifold.Telecom department officials say the reluctance of operators to invest in infrastructure is one of the reasons for poor call quality. An industry estimate shows the need for investing at least Rs 50,000 crore in the next 2-3 years by companies on telecom infrastructure.The service providers, in turn, blame it on difficulty in getting the nod for cellphone towers.With debt of more than Rs 7 lakh crore plaguing the sector, the companies have little headroom to spend more. India also has one of the lowest call rates in the world.“Telecom companies can complain but if they charge consumers, they will also have to provide good services,” said an officer in the telecom department who did not wish to be named, as he was not authorised to speak to the media.Signal strength of towers is one of many factors that decide call quality but strong signals from different providers can interfere, resulting in poor connection.Frequency is another factor. But the biggest issue, say telecom companies, is the difficulty in getting permission to set up towers, which leads to too many signals nesting in one. “Continuing to penalise telecom companies only increases litigation between them and the government. So let us work together in improving the customer experience,” Rajan Mathews, director general of Cellular Operators Association of India, said.The last time the regulator tried to penalise companies, the Supreme Court quashed the Trai’s proposal that customers be paid Re 1 for every dropped call with a maximum of Rs 3 in a day.“The physics of frequency is extremely complicated and there cannot be one reason for call drop. So, penalties levied by Trai are going to be challenged in court,” an official with a telecom major said on condition of anonymity.To ascertain the extent of call drops, Trai recently conducted a customer-satisfaction survey. Consumers in Delhi, Madhya Pradesh and Karnataka were very unhappy with the service, the survey report released last week said.In Delhi and Karnataka, around 65% customers said the quality of signal and network was poor. In Madhya Pradesh, the 58% of users were unhappy.