The demand for sensor hubs, dedicated processing elements used for low-power sensor processing tasks, is booming. In fact due to “always on” sensor processing trends and the limitations of battery technology, the overall market for all types of sensor hubs will exceed 1.0 billion units in 2015, rising to nearly 2.0 billion in 2018, according to IHS Inc. (NYSE: IHS), a global source of critical information and insight. Samsung, Apple and Motorola have already been using sensor hubs in their smartphones for a number of years, and Apple, Motorola and Microsoft explicitly advertise their use of sensor hubs or sensor cores in certain smartphones.

“The sensor hub market is incredibly dynamic, changing rapidly over the last two years, due in large part to Apple’s iPhones,” said Marwan Boustany, senior analyst for IHS Technology. “When Apple shifted from a discrete microcontroller to an integrated application-processor-based solution for the iPhone 6S line in 2015, it signaled to other manufacturers that this approach had reached maturity.”

According to the IHS MEMS & Sensors for Consumer and Mobile Intelligence Service, sensor hubs for high-end smartphones are changing rapidly from discrete microcontrollers (MCUs) used in the iPhone 6, Samsung Galaxy S6, and other high-end smartphones, to sensor hubs that are integrated into the application processor (AP), as in the iPhone 6S and Huawei Mate S.

“AP-sensor hubs will increasingly dominate the midrange to high-end smartphone segments in the next few years,” Boustany said. “Samsung is also testing alternative approaches to sensor hubs using a Global-Navigation-Satellite-System-integrated sensor hub from Broadcom in its Note 4 and S6 smartphones. We also expect to see sensor hubs that are integrated in the sensor package to make inroads in smartphones, especially in the midrange and low-end segments.”

As the use of AP sensor hubs rises, market share for MCU and other discrete sensor hubs will decline; however, because wearable devices require long battery life in a small package, they will continue to rely on discrete MCUs and field-programmable gate arrays (FPGAs). With increasing numbers of smart watches entering the market, Qualcomm’s Snapdragon 400 and other AP sensor hubs have also begun to penetrate the wearable-device market.

“Apple has chosen to use a discrete MCU in the first-generation Apple Watch, but the company may follow its handset strategy and integrate the sensor hub into its custom application processor in later generations,” Boustany said. “Smartwatches will likely follow trends seen in the smartphone segment, but with a higher penetration of MCUs than smartphones, due to tighter power-saving requirements.”