With at least 10wireless operators already offering native Wi-Fi Calling, the market is set to grow rapidly in the fourth quarter (Q4)2015, according to the Strategy Analytics (www.strategyanalytics.com) research group.

Unlike earlier versions of calling on Wi-Fi, native Wi-Fi Calling lets users make and receive calls and texts on their smartphones just as if they were on the cellular network, using the phone's dialer and contact lists. Calls can handover between Wi-Fi and Voice over LTE (VoLTE) during the call for a seamless customer experience.

Apple's support for Wi-Fi Calling in last year's iPhone 6 encouraged more operators to add the service capabilities to their networks and offer software upgrades for capable phones—certain models from Apple, Samsung, Microsoft and others. With 13 million new Wi-Fi Calling capable iPhones 6s and 6s+ just sold in the first weekend they were on sale, the number of wireless customers that can take advantage of Wi-Fi Calling is expanding rapidly.

Strategy Analytics says T-Mobile US has been the leading global operator championing Wi-Fi Calling, taking advantage of Wi-Fi to improve customer experience for in-building calling and international roaming, enhancing its competitive position. Around the globe, at least 10 mobile operators have commercially launched native Wi-Fi Calling, including T-Mobile US and Sprint, EE and Vodafone in the UK, SmarTone and 3 in Hong Kong and Vodacom in South Africa.

The number one driver for Wi-Fi Calling is to enable customers to make and receive mobile calls in areas with poor cellular signal but good Wi-Fi coverage, according to Strategy Analytics. Wi-Fi Calling enables both improved customer experience and new service offerings that can attract new customers, reduce churn and compete with over-the-top (OTT) services.