It is expected that fourth generation (4G) Smartphone base will jump from 5 million in 2015-16 to 180 million by 2017-18, leading to 4G subscribers accelerating from almost zero in 2015-16 to 90 million by 2017-18, a report by Bank of America Merrill Lynch said here on Saturday.

"We expect a faster acceleration towards 4G and see a large proportion of 2G subs leap-frogging 3G and moving to 4G. We expect 4G Smartphone base to jump from 5 million in 2015-16 to 180 million by 2017-18 leading to 4G subs accelerating from almost zero in 2015-16 to 90 million by 2017-18," the report said.

"It is expected that 4G net adds will be faster than 3G net adds by 2018-19 and estimate 3G subs to be largely restricted in areas where 4G coverage is limited," the report added.

The report said with Reliance Jio's launch expected to be in March 2016 or later, it is believed that the three big players - Bharti, Vodafone, Idea - will have a head-start in 4G and also have incumbency advantage.

"We think that continued delay from Jio will make it difficult for Jio to poach more high-end subs as the company would need to focus on offering a differentiated service as aggressive pricing alone would not be able to help Jio have a sustainable advantage," it added.

It considers that the top 5 percent customers of big three telecom companies, who contribute to 25 percent of revenues, to be sticky and unlikely to switch now with 4G being offered by their existing telecom operator.

"We estimate the big 3 telecom 4G market share to increase from 53 percent in 2016-17 to 60 percent by 2019-20 though we estimate Jio to have largest subs market share in 4G," the report added.