18 Jun 2010

Robin Heydon of CSR, looks at the latest developments in Bluetooth technology including ultra low power Bluetooth and Bluetooth 3 and asks about the future.

The inclusion of the Wi-Fi radio in the Bluetooth v3.0 specification brings a proven technology and one that already exists in many consumer devices today. Wi-Fi is a tested and understood technology both from a technical and end-user point of view. The inclusion of Bluetooth over IEEE 802.11 a/b/g - with the Wi-Fi radio acting as an AMP (Alternative MAC and PHY) - delivers the quick transfer speeds demanded by modern consumer devices - without suffering from battery drain issues.

By using the low power Bluetooth radio to monitor for connections the Wi-Fi radio is only used for the actual file transfer and therefore for the smallest time possible. This will allow wireless technology to be used by many more consumer devices that previously dismissed it due to power consumption issues.

For example, a user could stream video from their camcorder to their TV, or upload a whole music album from their phone to their MP3 player in just a few seconds.

Bluetooth V3

Managing the successful coexistence of embedded Bluetooth and Wi-Fi radios brings a whole new set of issues and challenges. Because both Bluetooth and Wi-Fi operate in the same 2.4GHz spectrum, it is quite a challenge making them work well together, especially if the radios need to be active at the same time. Current single-chip Bluetooth and Wi-Fi solutions on the market today are burdened with coexistence issues and cannot provide performance on par with standalone variants.

The key to ensuring coexistence lies in the software stack used by the device. While in theory the Bluetooth and Wi-Fi silicon can come from different vendors, because of the difficulties in managing the coexistence between the radios this is often not the case. Therefore, both radios and the software stack need to come from the same vendor, and this software needs to be carefully developed to manage the two radios without requiring additional input from the end user.

Bluetooth SIG

The Bluetooth SIG knows that ease of use is a key requirement for devices. Features such as Secure Simple Pairing that is also used by Bluetooth v3.0, allows devices to find each other much more easily and then secure the connections with the best user experience.

Similarly, Bluetooth v3.0 hides the radio used from the user. This means that if a large file needs to be transferred, the Wi-Fi radio will be turned on, the data transferred, and if not needed anymore will be turned off to conserve power. This increases data transfer speeds for Bluetooth and saves power, without confusing the user and it is the software stack's function to work out the best radio for the transfer. Bluetooth v3.0 therefore relies on an intelligent software stack, such as CSR's Synergy, to be effective. CSR Synergy is the only software stack on the market that has been ratified by the Bluetooth SIG as being compliant with Bluetooth v3.0.

Bluetooth v3.0 takes Bluetooth to the next step and will open up the market to hundreds of different consumer applications where previously wireless was not considered, or the application may not have even been thought of. While wireless in cameras has been tried without success before, the new standard could allow you to stream video from your phone to your TV or to upload a whole music album to your media centre in just a couple of minutes - both of which were previously impossible due to the battery drain of a phone trying to upload or stream this much data.

Summary

Bluetooth has reached a tipping point, and it could be argued that the technology has been pushed to its limit. The incorporation of Bluetooth low energy and the release of Bluetooth v3.0 open up new avenues to both Bluetooth and wireless technology as a whole. Bluetooth has evolved to provide the best adhoc wireless transfer technology around, and the latest adaptations are proof that it continues to be a powerful and evolutionary wireless technology.

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