TECHIE

The power of Bluetooth Low Energy

by BOGGURU

March , 2016
The new enhancement to the popular wireless technology allows devices to operate for months or years on batteries as small as a coin or button We all know and use Bluetooth. But the popular technology has evolved a lot and the latest enhancement is Bluetooth Low Energy that runs, as the name suggests, on ultra low power.Previous evolution of Bluetooth was mostly targeted towards adding more features and enhancing data rates. But this enhancement actually decreases the power consumption and allows devices to operate for months or years on batteries as small as a coin or button.
Speaking at a webinar, Naresh Gupta, vice president,Nucleus Software Exports and author of Inside Bluetooth Low Energy,explains how this new Bluetooth differs from other communication technologies and why it has the potential to change the wireless industry.




Bluetooth v/s Near Field Communication

One side are Global Positioning Systems and satellite communications that work across thousands of kilometres and on the other side are ultra wide bands that provide data rates of gigabytes per second. Then there is Near Field Communication (NFC) that provides very low data rates and works on very low distances (nearly 1 cm). Bluetooth Low Energy sits somewhere in-between. It provides bigger distances compared to NFC so the range could be 30 metres to 100 metres even as it provides low data rates. So typically, the data rates of Bluetooth Low Energy are lesser. They are in the range of a few kilobytes per second though theoretically, this technology can go up to maximum of 305 kilobytes per second.

Bluetooth Low Energy terminologies

Dual mode and single mode: Single mode devices are ultra low power energy devices such as watches, key or health equipments. These devices are sensors that collect information and send that information to another device.

For example, the second device could be a mobile phone. The phone classic Bluetooth devices. So, classic Bluetooth devices could be keyboards, mouse, printers and headsets that people have already been using. So without disturbing the practicality of existing devices, dual mode devices are able to talk to the new low energy devices.

Bluetooth SMART and Bluetooth SMART READY:

A Bluetooth Smart device gathers information and sends it to Bluetooth Smart Ready device. This device may either process the information (for example a mobile phone may display the heart rate on the screen itself) or relay the information for further processing (the heart rate may be sent to a doctor who may be in the remote part of world processing that information over the internet). So this whole ecosystem is allowing very small devices to gather information and then transmit it into any part of the world.

Key features

Ultra low power:

A device like a heart rate sensor will be mostly off. It gets switched on only when it has to send a reading and at that time it will do a very fast data transfer and then disconnect, which means that will again go into a low-power mode or off mode. What this technology does is it uses very small packets so that the radio consumes low power. The technology does it in a secure manner which means that the connection between two Bluetooth devices is encrypted. There are features that provide an encryption as a link and then this technology builds on the existing ecosystem.

Applications

Bluetooth Low Energy finds a lot of application in the healthcare industry. This can be a glucose meter, weighing machines, thermometers and blood pressure sensor. It has application in sports and fitness equipment. This could be shoes that track your movement -- how many miles you have jogged. It could be a satellite belt or exercise equipment or a security application.

For example, you could use your mobile phones to locate your lost keys. If you press a button on a mobile phone, key will start beeping.

How Bluetooth Low Energy works

Bluetooth architecture:

The lowest layers for the protocol stack run on a Bluetooth chip which is also called controller. The remaining layers may run on an application processor. For example, the mobile phone application processor may run on remaining layers of the stack. In that case, the application messenger is also referred to as a host. And the interface between the host and the controller is called the host controller interface. For example the application processor with the mobile phone may be connected to the Bluetooth tip on a USB interface.
So these three things -- the upper layer, the host controller interface and the controller lower layers -- form what is called the Bluetooth protocol stack. Besides stacks, the specification also designs the concept of profiles. Profiles are used case scenarios of protocol stack.

For example: Each layer of the protocol stack will define what are the features it provides and the profiles will define how these features are to be used to define a real work scenario. For example if the mobile phone has to connect to a headset, then the profiles will define what are the ingredients or layers that will be needed to make that correction to the headset.

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