Telcos using RTL technology to mask call drops, says TRAI

Telecom operators Aircel, Vodafone India and Idea Cellular are using call drop masking technology, or RLT (radio link timeout), incorrectly in Mumbai, the Telecom Regulatory Authority of India (TRAI) said on Tuesday.

“Most of the operators have focused on network improvement. However, usage of RLT (timeout period for releasing the call) by Aircel, Vodafone and Idea is incorrect and needs to be addressed immediately,” the TRAI said in its Mumbai drive test report.

With the help of RLT technology, a call remains connected even if a consumer moves to a poor network coverage area for which the person is billed.

However, industry lobby the Cellular Operators’ Association of India (COAI) has refuted the charges saying that the so-called call drop masking technology is actually a network parameter, which is a part of the GSM (global system for mobile communications) standards and is used globally.

COAI said RLT is just one of the parameters which decides for how long a call should be sustained if the signal quality drops below a certain threshold.

According to TRAI, most operators use RLT level of 40 units but some companies have been using it beyond their peers in a city.

“Such use will delay a dropped call by not providing any audio to the consumer and forcing him to disconnect, while charging him for the time the call was inaudible. Thus, the reduction in CDR (call data record) is not an accurate reflection of improved customer experience,” TRAI said.

Vodafone was found using higher RLT value than its peers in 97 percent of cell sites, Idea Cellular 80 percent and Aircel around 64 percent of cell sites.

Even Tata Teleservices Ltd was found using a higher RLT value in 23% per cent of cell sites in Mumbai. Vodafone has been found using a higher RLT value in Delhi and Hyderabad, and Aircel in Delhi and Chandigarh.

The drive test that was conducted randomly over a stretch of about 580 km between 10 and 13 May found MTNL (Mahanagar Telephone Nagar Nigam Ltd) 2G and 3G and Tata CDMA performance also very poor.

“Aircel 2G, Reliance 2G, Tata 2G and Vodafone 3G will need to focus on their call drop rate reduction while Idea 2G, all CDMA operators and specially MTNL 2G and 3G need to improve across all parameters, in order to offer acceptable levels of service,” TRAI said.