Bluetooth 4.2 increases shift of focus towards IoT

Latest updates to the short range standard improve security, privacy and add IP, but no support for meshing yet

The latest set of Bluetooth specifications, Release 4.2, offers an incremental step, not a major upgrade, but it continues the process of focusing the WPAN (wireless personal area network) standard increasingly on the internet of things (IoT).

It goes some way to addressing the challenge from the Thread Alliance to be the smart home standard, by improving IP support, though mesh capabilities are still absent.

The platforms’ governing body, the Bluetooth SIG (special interest group), converged its standard and low energy (Bluetooth LE) strands into a single effort with Bluetooth 4.0, published in 2010. However, since then, the expected growth in the number of connected devices has shifted the SIG’s emphasis increasingly towards those applications, where its technology has the opportunity to dominate in areas like the smart home.

This was seen in the 4.1 specifications, released last year, and now in 4.2, which continues to build on work in areas which are critical to the IoT, such as ultra-low power and security.

One of the key advantages claimed by the Thread Alliance – led by Google’s Nest unit and pushing its own platform as a smart home standard – is support for mesh. Although Bluetooth chip designers like CSR (being acquired by Qualcomm) are implementing that, it has not yet appeared in Bluetooth standards. The SIG says mesh is a “priority” but has given no timescales for support.

Despite the lack of mesh, the 4.2 release does address the other major advantage which Thread claims for its 6LoWPAN-based approach, over Bluetooth and ZigBee. This is full IP support, which Bluetooth is now addressing via a newly created profile, IPSP. This enables IPv6 for Bluetooth and means that BLE devices can connect directly to the cloud if required, rather than relying on a smartphone.

The new release offers other useful improvements for IoT designers, including improvements to power efficiency, faster data transfer, and new security and privacy mechanisms. Release 4.2 creates larger packets, boosting data rates by 2.5 times – which will become important in the smart home, where some machine-to-machine devices are starting to require full broadband connectivity, not the narrowband, low data rates of traditional M2M (although those will continue to suffice for a large number of sensors and gadgets, such as smart meters, indefinitely).

The larger packets will also reduce transmission errors, which helps to lower power consumption, said the SIG.

New security features include support for encryption and hash algorithms as recommended by the US National Institute of Standards and Technology (NIST). This brings the same level of security to Bluetooth LE (BLE) as to the standard’s Classic profile. Despite Nest’s sound and fury about mesh and IPv6, the most common criticism of BLE among its own developer base has been security, particularly vulnerabilities in the way it pairs devices with smartphones. That weakness will be addressed with 4.2, pledges the SIG, which has also introduced new privacy protection.

The new spec constantly changes MAC addresses so it is harder to track a device through its Bluetooth connection. It will also affect beacons – with Bluetooth 4.2, a handset will only wake up when it passes a store’s beacons if the user has whitelisted the shop.

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