Bluetooth 4.2: A New Instrument in the Engineer’s IoT Toolbox

The Internet of Things (IoT) market is set for explosive growth. A projected 30 billion devices will enter into the IoT ecosystem by 2020 according to the market research firm ABI Research. With billions of devices expected in the IoT and wearables markets, engineers at all levels are looking for a very low-power platform that will allow them to develop smart, connected devices in space-constrained applications.

For developers the key to the Internet of Things isn’t the things themselves, but the data these sensors and devices generate and the applications that will be built on top of that data. One of the design hurdles engineers face is the need to connect one or multiple wireless nodes to the Cloud and/or each other and they would like to use Bluetooth to do so because Bluetooth is already in a great many devices and is favored in mobile and wearable applications due to its low power profile. But unfortunately, Bluetooth devices have had to rely on WiFi (or another device entirely, such as a smartphone) to connect online, which has weighed against Bluetooth’s becoming part of the Internet of Things.

This limitation has not been lost on the Bluetooth Special Interest Group (SIG), which comprises over 24,000 member companies that collaborate, innovate and guide developments in Bluetooth wireless technology. Last month the Bluetooth SIG officially adopted version 4.2 of the Bluetooth core specification. Version 4.2 extends the features of Bluetooth Low Energy to allow easier IP connectivity. Other key updates in 4.2 include improved privacy and increased speed.

Let’s look at these advances one at a time.

The 4.2 update comes a year after 4.1 was adopted, which laid the groundwork for better Internet of Things (IoT) functionality, With a new profile known as the Internet Protocol Support Profile (IPSP), which enables Internet Protocol version 6 (IPv6) for Bluetooth, a sensor or other low-power device can access the Internet directly via IPv6 through a router or other access point without needing a go-between device. By way of review, IPv6 is the latest version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion when it became evident that far more addresses than the IPv4 address space has available were necessary to connect new devices in the future.

By increasing the capacity of Bluetooth Smart packets Bluetooth 4.2 will enable devices to sync data more quickly and reliably. In 4.2, Bluetooth LE becomes up to 2.5x faster than previous versions with a packet capacity increase of nearly 10x (again, compared to previous versions). As a result, over-the-air firmware updates for a Bluetooth Smart device are expected to be up to 250% faster and more reliable.

(Source: Bluetooth SIG)

Speed is increased through a Bluetooth LE data packet length extension which increases the length field from 5 to 8 bits and increases data payload length from 27 to 251 octets. With the new specification, there are some additional header fields and a trailer added to the packet to allow for additional payload per packet. The theoretical maximum data rate with Bluetooth LE (v4.0 and v4.1). was 236.7 kbps; with v4.2 this would increase to a maximum theoretical speed of about 650 kbps (however, as they say in car commercials when discussing mileage, actual—real world—results will vary and we know it will be considerably less than the theoretical maximum). All of this increases the effective throughput of the system—the amount of useful data sent—by reducing overhead and improving efficiency when transmitting data. Increased data transfer speeds and packet capacity reduces the opportunity for transmission errors to occur and reduces battery consumption as well.

The new version of Bluetooth also makes it more difficult to track devices through their Bluetooth connections. People shopping in stores employing Apple's iBeacons, which are low-power Bluetooth transmitters that can provide information to individual customers as well as track customer movements throughout the store, can't be tracked if they're using version 4.2 unless they specifically give permission for the beacons to interact with their device. This is possible because the new 4.2 spec will allow the MAC address of Bluetooth devices to be masked unless it is connecting to a trusted device.

Bluetooth 4.2 also introduces privacy settings that lower power consumption and build on the government-grade security features of the Bluetooth specification. This includes FIPS-compliant encryption for secure connections when pairing devices like Bluetooth home automation products (e.g., smart locks). The United States Federal Information Processing Standard (FIPS) defines security and interoperability requirements for computer systems that are used by the U.S. federal government.

The Bluetooth 4.2 standard is ready now, but device makers will still have to implement it and the consumer won’t get to use 4.2-capable devices until sometime later in 2015 as a result. (Product qualification was enabled for the new core specification on 9 December 2014). Design engineers can find the latest Bluetooth 4.2 technical details by reviewing the Bluetooth 4.2 core specification posted on this page: https://www.bluetooth.org/en-us/specification/adopted-specifications.

The Bluetooth SIG also offers a wide range of tools and programs to help with branding and promoting Bluetooth enabled product including the Bluetooth Smart Marketer Program. This no-cost offering can help generate publicity for Bluetooth Smart branded product through Bluetooth SIG’s brand expertise, public relations, social media and online channels. To learn more about all of the marketing programs you can leverage, visit: https://www.bluetooth.org/en-us/marketing/marketing-programs-update.