Tom explains the evolution and benefits of the latest Bletooth standard, Bluetooth 5.
Featuring Tom Merritt.
MP3
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Episode Transcript:
I have Bluetooth headphones that just magically connect without wires
Why can’t all my devices do that?
Can I get rid of WiFi routers now?
Are you confused?
Don’t be.
Let’s help you Know a Little more about Bluetooth
Bluetooth is a rather old wireless technology standard meant for exchanging data over short distances.
It was conceived of as a replacement for wires, originally RS-232 data cables, kids ask your parents. But it is now used to wirelessly connect LOTS of devices from keyboards to headphones to health monitors and more.
Bluetooth uses Ultra-High Frequency, or UHF radio waves between 2.402 and 2.48 Gigahertz.
It’s range is usually around 10-100 meters though Bluetooth 5.0 makes it possible to get up to 400 meters or in some cases as much as a kilometer.
It was originally standardized by IEEE as IEEE 802.15.1 but IEEE no longer maintains it. The Bluetooth Special Interest Group, or Bluetooth SIG and its 35,000 member companies manage it all on their own now.
If a manufacturer meets Bluetooth SIG standards, it gets a license for Bluetooth patents and the right to market its device as Bluetooth compliant, including using the Bluetooth symbol.
Bluetooth began with a desire to develop wireless headsets, and the Bluetooth earpiece was one of the first ubiquitous examples of Bluetooth technology.
The CTO of Ericsson Mobile in Sweden, Nils Rydbeck began developing the protocol in 1989. He assigned Todd Wingren to work on the spec and Jaap Haartsen and Sven Mattisson to develop it.
Principal design began in 1994 and a working solution was achieved in 1997.
Also, in 1997 the head of IBM’s ThinkPad R&D department, Adalio Sanchez, approached Rydbeck about integrating Erisson phones into ThinkPads. They ended up deciding to build Ericsson’s new short-range wireless tech into their devices to make that work. And because neither company had top market share, they decided to make it an open standard to encourage adoption.
Ericsson provided the spec and IBM contributed patents for the logical layer. Then Sanchez got Intel to join and Intel got Toshiba and Nokia to sign on.
Intel’s Jim Kardach proposed the name Bluetooth in 1997. He had been reading Frans G. Bengtsson’s historical novel The Long Ships about 10th-century Danish King Harald Bluetooth, who united disparate tribes into a single Kingdom. Bluetooth aimed to unite wireless communication protocols. The Bluetooth logo is a rune that merges the initials of Harald Bluetooth.
Bluetooth SIG was launched in May 1998 with those five companies, Ericsson and IBM as founders and Intel, Toshiba and Nokia as members.
The first consumer Bluetooth device, a hands-free mobile headset, won Best of Show at Comdex in 1999. Ericsson’s T39 became the first phone with Bluetooth to hit shelves and The Thinkpad A30 was the first laptop with Bluetooth, both arriving in 2001.
All right so how’s it work?
Bluetooth uses frequency-hopping spread spectrum in the globally unlicensed (though regulated) Industrial, Scientific and Medical bands, or ISM. So what that means is packets of data are transmitted on one of 79 different 1-Megahertz channels– and it keeps switching the channels fast to avoid interference and eavesdropping– with about 1600 hops per second. So a packet on channel 1 then a packet on channel 62 then one on channel 5 then back to one then to channel 42 etc. etc. Once two devices are connected by Bluetooth they know what the patterns of hops will be and no other device can easily predict it. The frequency hopping makes the signal very difficult to intercept, helping to keep it secure. Though they use encryption too so don’t fret. It does use some power to hop around like that so Bluetooth Low Energy only uses 40 channels and wider 2-megahertz channels.
One Bluetooth device can connect with to up to seven devices but only transfer data between one device at a time. Though it can rapidly switch between connected devices. It does not use the internet for its connections, instead creating what’s called a piconet – pico means very small–or sometimes referred to as a Personal Area Network or PAN. These devices all sync up their clocks as they hop frequencies and adapt to avoid frequencies being used by other devices or protocols like WiFi. And you may hear about something called a scatternet if you read up on this, that’s when more than one piconet connected to each other.
But don’t get too excited. Bluetooth is low speed, short range and prioritizes power efficiency. It’s not good for high-bandwidth or large amounts of data. That’s what WiFi is for.
So how these devices know who to connect to?
Bluetooth devices must be paired. Usually this works by making the device you want to connect– say a pair of headphones — available for pairing. Then you go to the device you want to connect to– say your phone and look in Bluetooth settings for the new device to show up. Most phones will ask you to confirm that you want to pair a device, and some devices, like car stereos, will ask for a confirmation code. Simpler devices like remotes may have a simpler way to connect. And a reminder, Bluetooth transmissions are almost always encrypted.
BUT the standard implementation remembers connections once you’ve approved them. And there are lots of attempts out there to trick you into approving connections without you realizing it. So it’s important to occasionally check what devices you have approved to connect by Bluetooth and maybe forget those you don’t recognize. You should also “forget” connections to headphones , cars and such when you get rid of them.
You may also want to force a PIN to be required to pair with your device, and you know, don’t use 1234 or 0000. It’s also not a BAD idea to turn off Bluetooth if you’re not going to use it, though that’s becoming an increasingly rarer condition for many users these days.
How far can I walk around with my Bluetooth device?
Range is determined by the class of radio and the environment in which it’s working. Most mobile devices have a class 2 radio which can reach up to 10 meters but in practice is somewhere between 5 and 10. Class 1 radios can theoretically go up to 100 meters but in practice get 20-30. There’s also a class 3 radio that has a range of about a meter. And Bluetooth 5 can do some tricks to increase range that we’ll get to later.
While Bluetooth does not need line of sight, walls and other obstacles can cause reflections of the signal that reduce range.
All Bluetooth versions have downward compatibility. Hardware with the newest version can work with all older versions.
Here’s some of the highlights of the versions.
Bluetooth BR/EDR which stands for for Basic Rate/Enhanced Data Rate came along with Bluetooth Version 2.1 offering simpler connectivity and better security.
Bluetooth 3.0 increased how fast data could be transferred and lowered power consumption.
Bluetooth 4 made Low Energy – aka Bluetooth LE– a priority, meaning you don’t have to worry anymore about whether your Bluetooth devices support it or not
Bluetooth 4.2 sent data at up to 1 megabit per second.
Bluetooth 5 increased that to 2 megabits per second.
Bluetooth 5 also increased the range the radios could achieve to up to 400 meters. Sort of. It does this by reducing the data rate so there’s more power behind each bit making it easier to detect. So a developer would have to choose to sacrifice bandwidth to increase the range, meaning this extended range is most common in Internet of Things devices – low bandwidth stuff like a door lock for instance. It’s also why I didn’t include the longer range in the description of the radios earlier. Of course Bluetooth 5 can also use its higher energy to transmit twice the data over a shorter range, hence the faster 2 megabits per second.
OK more recently
Bluetooth 5.2 was published on December 31, 2019 added features for Low Energy for Bluetooth LE, including Bluetooth LE Audio.
Bluetooth 5.3 was published on July 13, 2021 with a few improvements you won’t likely see in your day to day life but make developer’s lives easier.
And that’s Bluetooth.
I hope this helps you understand a little about how your wireless mouse and your ear buds work.
In other words I hope now you know a little more about Bluetooth.
This week, Dr. Nicole Ackermans looks at research into a new material that could change the game for solar power.
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