It had announced the latest quality of service regulations in August last year, revising the methods for assessing of call drops. The regulator had also increased the penalty to Rs 500,000 on telecom companies for not meeting the benchmarks. The revised methodology was to be done for all technologies — GSM, CDMA, WCDMA, LTE, etc.

In August 2016, when the consultation process was started to review quality of service (QoS), said Trai, many parts of the country lacked LTE networks. And, VoLTE (Voice over LTE) was not offered by any operator. Over the past year, LTE network penetration has increased significantly, with subscription having crossed 200 million.

Trai said the first VoLTE launch was in September 2016. Many operators providing LTE coverage have yet to offer it and might do so in a phased manner.

Almost all those having LTE networks in India have plans for VoLTE services.

Trai said in the case of 2G and 3G-based radio technologies, devices came into the market with voice capabilities from the outset. Voice services could have been provided by the same network on which they were camped. However, in the case of LTE, the situation differs on both networks and devices.

“For the purpose of voice, a user may be required to be pushed to other technologies i.e. fall back to Circuit Switched Technologies (CSFB), which might be a bit more time taking process than the usual call set-up time and affect the QoS experience,” Trai added. It said a need was felt to consult and deliberate on issues to identify QoS or measurement procedure for VoLTE. “This consultation is focused and limited to QoS issues related to voice services to LTE users,” Trai added.