Bluetooth low energy – the Momentum Builds
- Published
- in Wireless
It’s been a good week for Bluetooth low energy. At times it’s felt like a long, slow path since it was first announced as Wibree in October 2006, but that feeling is changing as the standard is coming to completion. This week saw the first Bluetooth low energy conference take place in Munich where chips vendors were showing off demos, whilst on the other side of the world, at the ARM Techcon in Santa Clara, there were more live demonstrations of the technology.
The mood of the industry has become increasingly upbeat. It was noticeable in Munich that a significant number of companies have moved from cautious interest to being serious about starting to deploy it. The questions that they are asking have changed to the practical ones of qualification and access to test equipment. That change in mood was reinforced by the Bluetooth SIG announcing that the specification is on course to be released this December.
The Bluetooth low energy standard can be confusing at first. Although it carries the name Bluetooth, it is a completely new radio with a completely new protocol stack on top of it. It has been designed from scratch to allow developers to add connectivity to products that only want to send small pieces of data on an irregular basis, but with such low power consumption that it can run on coin cells. The companies attending the Conference in Munich have understood that difference and are keen to exploit the new products and service models that Bluetooth low energy offers.
What does the Bluetooth low energy model mean? Typical applications that send small bits of data are many and varied. They include TV remote controls, room thermostats, key tags, alarm clocks, running shoes, weighing scales, fall alarms – the things we use in everyday life that occasionally need to tell us something. The important thing is that they don’t do it all the time. That means that they can often run off a small battery that lasts for the life of the product. Bluetooth low energy is designed to let them acquire the ability to send that data wirelessly without having any significant impact on the battery life. It means that all of these products that have never communicated before can start to have conversations – sending their data to a mobile phone or a website. 
To repeat the important bit, Bluetooth low energy is a new radio. It works at the same 2.4 GHz frequency as normal Bluetooth, but the two can’t talk to each other. Which makes people wonder why it’s called Bluetooth? The reason is that it has been designed so that it is possible to make silicon chips that include both Bluetooth and Bluetooth low energy within the one chip. The clever piece about this is that the design of Bluetooth low energy lets it share much of the same radio, and use a combined protocol stack.
There’s a lot of clever technology in doing that. What it means in practice is that chip makers can produce a chip that can talk Bluetooth to your headset at the same time that it is talking Bluetooth low energy to your running shoes. These chips are called dual mode chips. And because they share most of their circuitry across these two standards, they’re no bigger and cost no more than today’s ordinary Bluetooth chips.
Dual-mode chips will start appearing in handsets and laptops in the second half of 2010. As well as supporting all of the traditional Bluetooth applications and use cases, they’ll be the beginning of an ecosystem of Bluetooth low energy devices that will start to open up a whole new world of applications and opportunities. 
At the device end, there will be small, low cost chips that only implement the low power part of the Bluetooth low energy standard. CSR explained that they’ve been able to put the entire Bluetooth low energy standard onto a chip that is just 4.5mm square. That’s so small you can fit two of them onto your little finger nail. So they can be added to almost anything – it’s smaller than the battery.
This is where things get exciting. All of these new devices will be able to send data to a mobile phone, which can act as a gateway to transfer it to a web application. That means that everyday devices can start to communicate with web services. Unlike any standard that has come before, Bluetooth low energy describes how data gets from the device all of the way to the web. That allows handset vendors to ship their phones with a generic gateway function that will work with any device. There are two important consequences that come out of that:
- Any device that contains data can talk to the web.
- Applications developers and service providers can offer services for these devices.
A device doesn’t need to be complicated to generate data. Some data is obvious, like weight, or temperature or blood pressure. But most devices contain intrinsic data. Light switches have binary ON/OFF data. A chair knows that someone is sitting on it. A stapler knows it has run out of staples. A tennis racket knows you have hit the ball (or missed it). Bluetooth low energy allows product and application designers to think about what all of this intrinsic data means and how it can be used, particularly when it’s coupled with a web application.
In Munich, we heard from many industry sectors. We heard about the need for connectivity in health and wellness devices. Suunto talked about its use in sport and fitness equipment. Emerson told delegates about the way they plan to use it in home automation, adding it to everything from central heating and air conditioning to smart energy metering and swimming pool controls. It’s generating interest from car manufacturers, who want to take advantage of it to remove wiring. And network operators are keen to exploit the new service models that come from connecting devices through mobile phones.
For designers, the tools and chips are starting to arrive. TI, Nordic and CSR were updating delegates on their chips at the Munich Conference, just hours before EM Microelectronics and Triad were doing the same in California. Momentum is gathering – there’s a strong feeling that with the standard nearing completion and multiple vendors launching chips, that 2010 will see the first products in the shops. If you’ve not started looking at it, now’s the time to get to know Bluetooth low energy.
GPS in a phone is passive – it just tells you where you are. In order to send that information to anyone else, you need to install a program. Depending on the application it could send youy location all of the time. More often it’s likely to do it only when you instruct it to.
As sending information involves the cost of sending data (which gets expensive if you’re roaming outside your country) it’s highly unlikely that this will be turned on by default. So it’s up to the user to decide what they want to do with the technology.
I am curious how many will opt willingly for GPS inside their phone once it arrives to the mainstream.
Limited GPS tracking seems a better future for those who value some degree of privacy and security.
Legally speaking, taxis, buses and subway transit groups would need to opt into the scenario for phones to work …no?
Thanks Nick…
It could, but there’s no reason why you can’t do this from your phone. More and more phones already include GPS and there are applications available that will allow you to transmit your location. I don’t know whether anyone has developed this particular application of notifying a person you’re driving, or walking to meet, but that’s just some web software.
Some of the new chips that will integrate Bluetooth low energy into phones also contain GPS circuitry, so that will increase the percentage that have this capability
Here is a scenario…while driving my car, can this new low energy bluetooth technology transfer my car’s GPS interface screen data to the person I am talking to on my mobile phone? (maybe their computer screen or their mobile screen or even their car gps)
I would like to share my route information and trip status with the person I am meeting with.
If so…can I also send out live trip status reports to selected persons…say every 5 minutes or so?
Thanks…
No. In a dual mode chip the radio is effectively multiplexed between the two different standards. The output section, receiver and antenna are common. That was one of the key starting points for Nokia when they developed it as Wibree – that there should be no additional components on the pcb. And that concept has remained key.
The basebands are distinct in terms of what they do, as the link management is fundamentally different for the two standards. However, as they are implemented in firmware, that’s just an implementation issue. That will be done by the chip supplier, so is only really of academic interest to others.
Another fundamental requirement is that adding low energy functionality to a dual-mode device does not degrade the existing Bluetooth experience, particulary for voice or stereo music. That is accomplished in large part by the low duty cycles and fast atomic transfers within low energy. This specific aspect has been very throughly tested throughout the evolution of the standard as it is a key criterion for its release.
In a dual mode implementation, will the two radios time share the same antenna?
If so does it imply that the normal bluetooth radio baseband will be tweaked to facilitate that?
How will a dual mode device perform a continuous scan for low energy devices when say it is already in an aggressive normal bluetooth scenario where 3 sco channels are active?