More than one billion 4G smartphones are expected to be shipped in 2016, as emerging markets start to catch-up in using the high-speed wireless mobile telecommunications technology, according to research firm International Data Corporation (IDC).

IDC’s latest forecast reveals that the growth of 21.3% year-on-year will take volumes to 1.17 billion, from 967 million in 2015.

In total, global smartphone shipments are anticipated to reach 1.45 billion units with a year-over-year growth rate of 0.6% in 2016.

In emerging markets defined as Asia Pacific excluding Japan, Latin America, Central and Eastern Europe, and Middle East and Africa, 4G smartphones will make up 77% of the total, up from 61% in 2015.

The 4G adoption growth in mature markets such as the US, Canada, Japan, and Western Europe is expected to increase to 94% in 2016, from 85% in 2015.

IDC’s Worldwide Quarterly Mobile Device Trackers associate research director Melissa Chau said: “It’s been a long slog for 4G uptake in many emerging markets as 4G data tariffs have long been very expensive compared to 3G, while 4G handsets themselves have also been relatively pricey across the board.

“We are quickly seeing this change in key growth markets like India where new operator Reliance Jio is aggressively trying to shake up the market by handing out free 4G SIM cards and launching own-branded low-cost 4G-enabled smartphones.”

The research firm cited Google’s renewed smartphone efforts in 2016 with its Pixel line, while acknowledging that early supply chain indications are that volumes are not at the point where Samsung or Apple should see a significant impact for the fourth quarter.

IDC’s Worldwide Quarterly Mobile Device Trackers program vice president Ryan Reith said: “Of course, as we head in to 2017 this can change, but many eyes will be on Google to see how serious they are about pursing the hardware play.”

IDC said Google’s Android operating system (OS) has been and will remain the majority share platform in smartphones for the foreseeable future.

Android OS will also be at the core of the aforementioned 4G growth anticipated in emerging markets.

Windows Phone shipments are expected to decline 79.1% in 2016 as the number of OEMs supporting the platform continue to become less.

Apple’s iPhone 7 and 7 Plus have performed well. However three quarters of year-over-year declines, as well as an expected fourth quarter decline by IDC, will account for negative growth, the report added.