Ultra-low power and network flexibility will give ANT an advantage when smartphones start talking to everything with an electronic pulse.

Sony Ericsson’s Xperia active is compact, light, water-resistant and aimed at people who take fitness seriously and were likely to already be familiar with ANT. (Courtesy: Sony Ericsson)Convergence is a hot topic again. But this time its impact on people’s everyday lives will dwarf the computer-communications-consumer (3C) version of the 1990s. Today, the design community is being challenged to find ways to link any device that potentially can draw electric current with the rest of cyberspace. Watches, toasters, weight scales, and thermostats; bicycles, blood pressure monitors, and smartphones are just a few candidates for the new convergence.

In the tiniest and most cost sensitive devices, power consumption will be an important consideration but other design issues such as network topologies and security will be also feel the pressure to simplify, simplify in order to achieve optimal results.

The latest generation of smartphones are the driving force behind the convergence of computers, communications, and the ‘Internet of Things’ — the term used to describe a network of everyday devices (such as toasters, key fobs, thermostats) that seamlessly link to the global information network and become active participants in business processes.  Mobile phones are very people-centric: almost everyone has one and carries it most of the time. Smartphones are the ideal universal jumping off point from Personal Area Networking (PAN) to the Internet of Things and to the myriad applications, widgets and tools that enable the anywhere, anytime computing paradigm.

Ultra low power (ULP) wireless enables the coin cell-powered devices that make up a PAN to communicate. Smartphone manufacturers, keen to ensure their products cements their position as the hub linking PANs to the Internet are now incorporating the technology into their latest handsets.

ANT on the Move

Since Dynastream Innovations and its ANT protocol are best known in the design community for a strong market position in fitness applications, sensor-data acquisition, and PANs that link watches and dedicated, single-use devices to PCs, it may come as something of a surprise to find out that the technology is also present in many of the smartphones on the shelves today - even those where it’s not listed in the feature set.

Through the use of a dongle or USB stick, many smartphones can take advantage of the ANT protocol for recording and monitoring fitness activity and any of the hundreds of other coin-cell battery powered applications. A significant breakthrough came in June 2012 when ANT Wireless announced ANT + Android USB support with version of the Android platform from 3.1 and above, thereby providing a link from millions of existing and future Android phone and tablets. Previously, Android was excluded and only dongles for iPhones were available from third-party companies.

Accessories such as heart rate monitors, wirelessly paired with a smartphone app, are creating a new sector known as ‘appcessories’. (Courtesy: Wahoo Fitness)Most smartphone users would prefer not to use a dongle or USB stick, of course; and it turns out, with a little bit of cooperation from the handset vendors, that in the future they won’t have to.  Smartphone manufacturers do not even have to add any additional hardware to activate ANT. “All multimode communication chips from the major vendors support ANT,” says Rod Morris, Vice President of ANT Wireless at Dynastream. “All the major smartphone vendors need to do is to turn it on with a software update. We are actively encouraging them to do just that.”

Sony Mobile was the first major vendor to turn on the ANT protocol and promote its advantages. ST-Ericsson’s multimode communications chip, the CG2905 GNSS/Bluetooth/FM device was unveiled in the Sony Mobile’s Xperia active model. Xperia active was chosen for good reason – it is compact, light, water-resistant and the perfect companion for people who take fitness seriously and were likely to already be familiar with ANT.

With the Xperia experience under its belt, Sony Mobile now fields 16 ANT-enabled models and is committed to offering ANT across its entire smartphone product line. Another prominent smartphone maker, Taiwan’s HTC Corp., integrated ANT into the link layer of the multimode chip of its Rhyme Android phones so it can operate concurrently with Bluetooth and Wi-Fi. ANT-enabled Rhyme phones are particularly popular with the bicycling community – a sector where ANT is considered a de facto standard.

Another multimode communications chip for smartphones that provides ANT support is Texas Instruments’ WiLink 8, which supports Wi-Fi sensor systems, Bluetooth low energy, ANT+, and NFC. WiLink 7 also integrated ANT. Other silicon vendors whose names cannot be disclosed are also supporting ANT, says Morris.

ANT’s Installed Base

There are two compelling reasons for mobile phone designers to turn ANT on. The first is its ULP capabilities, which make it a good choice for any designer of a peripheral device with stringent power restrictions that needs to communicate with a handset. These products will create new ecosystems for smartphones. ANT’s installed base is just as important: There are already 60 million ULP systems such as heart-rate-monitor (HRM) watches in the market combining Nordic Semiconductor’s nRF24AP2 hardware and ANT software.

The introduction of Nordic’s third-generation nRF51422 ANT chip in June 2012 will go a long way to clinch the deal. The nRF51422 combines a lower-power radio than the previous ANT chip and now integrates a powerful 32-bit ARM Cortex-M0 processor. A major benefit is achieved in this new chip by separating the ANT protocol stack and user application code. This provides developers a clean boundary allowing them to focus design efforts on the application safe in the knowledge that the ANT RF protocol is protected and will operate perfectly.

“Nordic’s nRF51422 ANT chip will be used by third-party product developers for coin cell-powered accessories that are designed to communicate with smartphones,” says John Leonard, Nordic Semiconductor’s Tactical Marketing Manager. “These accessories, wirelessly paired with a smartphone app, are creating a new sector known as ‘appcessories’.

“For example, an accessory such as a heart rate monitor will communicate with the smartphone, which, using the app, processes the data to track trends, motivate the user, and share the information with friends,” continues Leonard. “Developers can use the huge smartphone ecosystem to support these appcessories instead of writing bespoke software that users will have to download and/or configure.”

Topologies and Applications

ANT boasts a key advantage that makes it a good choice for the appcessory sector. Designers can implement a peer-to-peer model in which devices communicate independently with each other over up to eight channels. This benefit is a legacy of ANT’s original use model for sports watches paired with fitness sensors: It was assumed that all devices on the network would operate on a coin-cell battery so either could operate as master or slave. So now, for example, ANT allows a sports watch to be the master and the mobile phone to be the slave when it is appropriate.

In some cases, this network flexibility is decisive in determining product viability. For example, when engineers at DexCom Inc. started designing the smartphone-enabled DexCom continuous glucose monitoring system that can report glucose values every five minutes, they had to meet stringent power requirements: Once attached to the patient, the monitor had to operate for a week; and, there had to be support for multiple displays – the watch, the phone and potentially one for the physician’s remote office location. In this use case, the cell phone had to be the slave making ANT the best choice for ULP wireless connectivity. 

In the brave new world of ubiquitous connectivity, the smartphone is destined to play a central role in a system linking cellular networks and the conventional Internet to potentially billions of tiny coin cell-powered accessories forming a new Internet of Things. Realizing this vision requires a solution to the challenge of price, power consumption and network flexibility. ULP wireless technology is the answer.

About the Author

Jack Shandle is a freelance writer specialising in semiconductors. He was commissioned by Nordic Semiconductor to write this article.