The demand for interoperability
A proprietary wireless connectivity solution (i.e. one that uses technology belonging to a single company) will always outperform an interoperable technology such as ZigBee or Bluetooth. Why? Because the manufacturer is able to optimize the protocol without the encumbrance of the additional overhead required for assured interoperability. The benefit is a more efficient solution with lower power consumption and reduced cost. The drawback is that lack of interoperability.
A proprietary wireless connectivity solution’s lack of interoperability with devices from other chip manufacturers is a problem for OEMs that require a technology that’s guaranteed to seamlessly connect with wireless chips in other companies’ products (for example, the bike computer in the example above linking to sensors made by other firms). Such standardized interoperability is typically underwritten by a formal alliance of commercial companies such as the ZigBee Alliance, standards bodies such as IEEE, or trade associations such as the Bluetooth SIG. Products must be tested to the relevant specification in order to qualify for interoperability certification to a particular standard.
Although enhancements to standards can take a long time to emerge, and testing to gain certification takes time and adds expense for product developers the advantages are significant. Interoperable solutions tend to stimulate market growth because equipment manufacturers gain confidence that the technology will be available for many years; there is a multiple source chip-supplier market, increasing competition and driving down prices, and quality is assured because chip makers have to pass a regulated certification process.
The ANT+ technology described above is one example of an interoperable ULP wireless technology. It is supervised by an alliance of over 220 companies and has been adopted as a de facto standard by manufacturers such as Garmin and Trek in the cycling sector. And, recently, in addition to Nordic Semiconductor, another semiconductor company has started to offer ANT chips. However, the most successful interoperable short range RF solution (in terms of shipment volumes) is still Bluetooth wireless technology.
The Bluetooth SIG has extended its Bluetooth technology with a version that can operate from coin cell batteries. So-called Bluetooth low energy has been designed to allow sensors and peripherals to communicate with each other and devices such as the next generation of mobile phones. In December 2009, Bluetooth low energy was adopted as part of Bluetooth Core Specification Version 4.0. Nordic Semiconductor has played a significant role in the development of the specification, donating its extensive ULP wireless design heritage to the technology.
Semiconductor vendors are now shipping Bluetooth low energy chips. Nordic, for example, recently announced the first in its µBlue™ Series of Bluetooth low energy chips. The first product in the µBlue family is the nRF8001 – a complete Bluetooth low energy solution in a 32-pin 5 by 5mm QFN package incorporating a fully embedded radio, link controller, and host subsystem - suitable for watches, sensors and remote controls among other applications. Casio’s recently released G-SHOCK Bluetooth Low Energy Watch uses this chip. (See Figures 3a and b.)
The watch is one of the first commercial products to employ Bluetooth low energy and includes features such as time correction from smartphone to watch, incoming call, email and SMS alert notifications from smartphone to watch and a finder function that enables users to locate a misplaced phone.
Figures 3a and b: Nordic’s µBlue nRF8001 is the company’s Bluetooth low energy chip and has been selected by Casio for its G-SHOCK Bluetooth low energy watch
The Bluetooth SIG’s stated intention is to follow up the publication of Bluetooth Version 4.0 with the release of Profiles for Bluetooth low energy technology including Personal User Interface Devices (PUID) (such as watches), Remote Control, Proximity Alarm, Battery Status and Heart Rate. Other health and fitness monitoring profiles such as blood-glucose and -pressure, cycle cadence and cycle crank power will follow. (See Figure 4.)
Figure 4: Early applications for Bluetooth low energy will be in the sports, healthcare and entertainment sectors
(Click on image to download larger version.)
The low cost and low maintenance (because batteries require only infrequent changes) of Bluetooth low energy sensors will encourage widespread use in public places. One key application could be indoor location (where there is no GPS signal) whereby sensors around a large public building (such as an airport or rail station) constantly broadcast information about their location. A Bluetooth low energy equipped cell phone passing within range could then display that information to its owner. Sensors could transmit other information such as flight times and gates, location of amenities, or special offers from nearby shops. (See figure 5.)
Figure 5: Inside a large building such as an airport terminal Bluetooth low energy tags could be placed in strategic locations to inform cell phone-equipped passengers of their location
Bluetooth v4.0 chips are also becoming available. Devices such as cell phones should start to incorporate these devices in the second half of 2011. Once that happens, the full potential of this exciting new technology will start to be realised.
As Nordic Semiconductor’s CEO, Svenn-Tore Larsen, puts it: “Once designers have an inexpensive way to add an interoperable wireless link to anything that’s battery powered, even devices with the smallest batteries, the application potential is vast. Designers will come up with thousands of ways to use that link.”
About the Author
Jay Tyzzer is a U.S.-based senior applications engineer with Nordic Semiconductor. The company is a leader in ULP wireless connectivity in the 2.4GHz Industrial, Scientific and Medical (ISM) band. In 2010, the company shipped over seventy million transceivers to leading consumer electronics manufacturers. For more information on Nordic Semiconductor’s nRF24LE1, nRF24AP2 and Bluetooth low energy wireless technology products please visit www.nordicsemi.com