Bluetooth v4.2 – improving speed and security for wireless devices

After starting from humble beginnings, the Bluetooth standard keeps improving and now the Bluetooth Special Interest Group (SIG) has recently officially adopted the new Bluetooth Core Specification version 4.2.

This new specification promises improvements in the speed, security and privacy of Bluetooth networks as well as ease of IP network connectivity for Internet-of-Things applications. The new and improved features of version 4.2 build upon the capabilities such as  Low Energy in the Smart (v4.0) standard, aiming to further improve the position of Bluetooth Smart as a key enabling technology for the Internet of Things.

The SIG has emphasised "Connected Home" scenarios as being well placed to take advantage of the capability for direct Internet connectivity provided in version 4.2, also emphasising the advantages offered by IPv6 support and higher data rates whilst also maintaining strong energy efficiency.

Bluetooth 4.2 introduces several major updates to the specification - Low Energy data packet length extensions, secure connections, privacy upgrades, and the IP Support Profile, which helps to enable IoT applications. Version 4.2 will extend the capabilities of Bluetooth 4.0 to allow low-power IP connectivity over Bluetooth, with the new IPSP (Internet Protocol Support Profile) profile which supports IPv6 and 6LoWPAN connectivity.

Bluetooth-networked edge-node devices will be able to use this to directly access the Internet via an Internet connection elsewhere in the network, without having first to be tethered to a specific smartphone or other Bluetooth-enabled device with IP connectivity.

Furthermore, version 4.2 increases the speed and reliability of data transfers between Bluetooth Smart devices. Standard Bluetooth packets offer a maximum payload size of 1021 bytes, but in the 4.2 specification there are some additional header fields and a trailer added to the packet to allow for additional payload per packet, with the length of data packets transferred increased from 27 bytes to 251 bytes.

This increase in the data transfer rate corresponds to a speed increase of up to 2.6 times, compared to older standards. Bluetooth master and slave devices, however, will still have the ability to reduce or otherwise negotiate the maximum length of packets to transmit and receive.

These speed increases are very valuable for developers looking to create systems where the transfer of larger amounts of data over Bluetooth is required - for example regular firmware updates or the downloading of large amounts of sensor data in data logger or similar Internet-of-Things applications. Increased data transfer speeds and packet sizes in Bluetooth 4.2 also reduce the opportunity for transmission errors to occur, resulting in more efficient communication and a reduction in battery energy consumption.

Building on the speed improvements, Bluetooth 4.2 also introduces advances in security and privacy over older Bluetooth implementations, as well as lowering power consumption. For example, a department store may implement Bluetooth iBeacons to track the movements of consumers around the store, which could be considered an invasion of privacy.

Bluetooth 4.2 addresses this by allowing the MAC address of a device to be masked from other devices unless the iBeacon or other Bluetooth device being connected to is explicitly trusted, preventing this kind of tracking from occurring unless the user has enabled permission for the iBeacon to engage with their device.

Therefore devices compatible with Bluetooth 4.2 will only "wake up" when a device such as an iBeacon that is designated as trusted is within proximity. This has the added bonus of lowering power consumption on the smartphone or other Bluetooth device, since it won't wake up from a low-power state whenever it passes near such a device - it will stay asleep by default.

The previous Bluetooth 4.1 specification introduced AES encryption, and the Bluetooth 4.2 update now completes these security upgrades by adding full public key cryptography for authentication in Bluetooth Low Energy mode using FIPS (Federal Information Processing Standards) compliant algorithms, essentially updating security for Bluetooth Low Energy to the same standard as Bluetooth Classic - so you can have confidence in the cryptography used.

Dual-mode Bluetooth devices now only need to pair once and they will retain the same fully secure connection, regardless of which mode was used to authenticate.

IP connectivity is also improved with 4.2, as the new Internet Protocol Support Profile (IPSP) will allow Bluetooth Smart sensors to access the Internet directly via IPv6 / 6LoWPAN. IP connectivity makes it possible to use existing IP infrastructure to manage Bluetooth Smart "edge" devices, which is ideal for connected home and Internet-of-Things applications that need both local control - from local network devices such as smartphones, and wide-area control over the Internet.

IPSP is designed to enable IPv6 for Bluetooth, meaning that devices such as wireless IoT or wearable computing platforms can use Bluetooth Low Energy to talk to the Internet without the need to be paired to another device such as a smartphone or tablet to act as a bridge to the IP network.

Data can go directly to and from low-power Bluetooth devices and the Internet, as long as there is a router or access point in the home equipped with Bluetooth physical-layer hardware. This means that IPSP is arguably the biggest news about Bluetooth 4.2, particularly for IoT device development.

We’re excited about these latest developments in Bluetooth and if you’re considering a new Bluetooth-enabled product or upgrading an existing device – our team at LX can partner with you for mutual success. Getting started is easy – click here to contact us, or telephone 1800 810 124.

LX is an award-winning electronics design company based in Sydney, Australia. LX services include full turnkey design, electronics, hardware, software and firmware design. LX specialises in embedded systems and wireless technologies design.

Published by LX Pty Ltd for itself and the LX Group of companies, including LX Design House, LX Solutions and LX Consulting, LX Innovations.