Bluetooth 5 extends the IoT but remains low power
Bluetooth has become one of the key standards for IoT, thanks to its low power credentials. The Bluetooth Special Interest Group (SIG) has announced the arrival of the new version of the Bluetooth Low Energy standard – Bluetooth 5, due for release towards the end of this year.
The current Bluetooth low energy standard has proved to be popular in consumer goods, such as wearables like the Misfit Shine activity and sleep monitor. For these constrained embedded devices, the connectivity via Bluetooth to companion smartphone apps ensures a power efficient transfer of sensors data.
FIGURE 1: Wearables, like the Misfit Shine, use Bluetooth Low Energy to synchronize data. (Picture credit: MisFit)
Bluetooth 5 will bring some improvements to the 4.2 standard whilst keeping the characteristic low power credentials. The new standard doubles the transmission rate to 2-Mbit per sec, quadruples its range, and increases the data broadcast capacity by a factor of eight.
For Bluetooth 5 to stay true to its low energy credentials despite these increases in speed, range and capacity, it requires changes from the transceiver through to the stack. ARM is the only company to offer a complete Bluetooth RF-to-stack-IP solution designed completely in house. As such, it believes it has a unique position to lead the market in implementation and enablement of these features.
Increased data rates
The benefits from an increase in transmission rate with the Bluetooth 5 standard are obvious. Higher quality streaming is now possible, but so too is faster connectivity with devices. Removing the latency currently sometimes experienced with information updates from device to app creates a slicker, better user experience. Another benefit is that devices will need less time to transmit their data, thus being able to go back to a low power state faster, further improving battery life.
This transmission rate enhancement, combined with the sub-volt technology implemented by the Cordio family of radio IP from ARM, makes energy harvesting a reality more realistic approach. With transmission being faster, the amount of energy required to transmit a given amount of data will be reduced. Deep-sleep current of <1µW and Tx/Rx peak current of <8mW result in average current draw of 10 to 100µW, which is feasible from energy harvesting sources such as solar, thermal, vibration and even RF power harvesting.
Figure 2: An example of ARM Cordio radio IP integration. Each Cordio solution has a pre-qualified, self-contained radio block, link layer firmware, stack and profiles.
The increase in range is a key benefit. Coupled with the forthcoming mesh networking support, it will make Bluetooth a strong candidate for smart home applications, providing whole-home coverage without a change in the power consumption of devices. Kitchen appliances will be able to be controlled from anywhere in the home, for example, via a seamless and robust local network.
The 800% increase of data broadcasting capacity will result in more meaningful and fuller information, and allow richer IoT applications independent of companion devices. At the moment, beacons can only send a small amount of data, and many rely on sending a link to a website to provide additional information. An increase of broadcasting capacity will enable full content to be sent, without having to rely on external websites. This will open up a plethora of applications, where information becomes available, with connectionless services and a move away from the app paired to a device model; the revised model will mean there is no need to download an app, or connect the app to a device for the full information or experience.
Prithi Ramakrishnan, Product Manager at ARM’s Wireless Business Unit, is confident that the Cordio radio IP can fit into the Bluetooth 5 model straight away. “The Cordio radio IP has had 2-Mbit per sec capability for several silicon versions, and can support the newly announced enhancements with no additional modifications,” she says. “We have demonstrated this at Bluetooth World 2016 and recently at DAC 2016”. A video of this demonstration can be found here.
Bluetooth low energy continues on its path to become the invisible technology that will broker the interaction of many IoT devices. Developers will be able to exploit the enhanced Bluetooth 5 capabilities, which will find a quick route to market as the ARM Cordio radio offers support from day one.