Bluetooth Low Energy / Wibree

- an overview of the Bluetooth Low Energy system formerly known as Wibree standard

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Bluetooth low energy or Wibree as it was originally called is an industry standard for enabling wireless connectivity between small devices. The new Wibree technology has been developed by the Nokia Research Centre, and it is hoped Bluetooth Low Energy / Wibree will become an industry wide wireless standard.

The Bluetooth Low Energy / Wibree standard offers a number of advantages:

• Ultra low peak, average & idle mode power consumption
• Ultra low cost & small size for accessories & human interface devices (HID)
• Minimal cost & size addition to mobile phones & PCs
• Global, intuitive & secure multi-vendor interoperability

It is claimed that the new Wibree technology complements other local wireless connectivity technologies, and only consumes a fraction of the power. This enables it to be used in small electronics items such as button cell powered devices where power is particularly limited. As a result it is anticipated that Wibree will find a wide variety of uses in applications ranging from watches, wireless keyboards, toys and sports sensors.

Although Nokia took the lead in the development of Wibree, other companies are now involved as the aim is to make it an open standard. The members of the group defining the specification now include: Broadcom Corporation, CSR, Epson and Nordic Semiconductor having licensed the Wibree technology for commercial chip implementation. In addition to this the sports equipment manufacturer Suunto and Taiyo Yuden are contributing to the interoperability specification in their respective areas of expertise.

Bluetooth Low Energy / Wibree specification

Although some experiment and demonstrations have been undertaken at the Nokia Research Centre to check the viability of the Wibree standard, comparatively little has been firmed up yet. The idea is that all partners in the group will be able to contribute to the Wibree standard and in this way it will have a wide degree of industry acceptance.

Some items basic elements of Wibree have been defined. Wibree will operate in the 2.4 GHz ISM band and it will have a physical layer bit rate of 1 Mbps. Even with its very low power level it is able to support communication over distances up to five or ten metres.

There are some further outline requirements for Wibree that have already been laid down, although the way in which they will be implemented has not been decided. The standard will not use frequency hopping techniques like Bluetooth. The reason is that this technique, while very useful in reducing interference uses more power, and one of the chief aims for Wibree is that it will be a very low power technology.

The Wibree standard will also be designed to enable dual-mode implementations to reuse some Bluetooth RF technology. This will also help the standard complement Bluetooth and this is hoped to provide some early acceptance.

Facilities will be added to Wibree to provide the equivalent of the Bluetooth Service Discovery Protocol that prevents sending in appropriate data to devices that are connected, i.e. audio to a printer, or data from a keyboard to a headphone. Again, details of this are yet to be defined.

One fact that has been stated is that the transmitted data packets will be dynamic in size, in comparison with Bluetooth packets that have a defined fixed length. By transmitting only as much data as is needed power will be saved.

Bluetooth Low Energy / Wibree summary

As the first announcement about Wibree was only made in October 2006, and few details have been defined, it will take some time for the work to be completed. Yet despite this it is anticipated that the first releases of the specification will be available by end of the second quarter of 2007, and devices late in the year. It will be interesting to see how Wibree is accepted by the market and whether it takes off in the way Nokia hopes.

By Ian Poole

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