Bluetooth, the curiously named communication standard has taken the world by storm. Now a given feature on everything from smartphones to in-vehicle entertainment systems, Bluetooth has an interesting history and working, proving how versatile this communication standard is. It is managed by the Bluetooth Special Interest Group (SIG), a non-profit, non stock company which mainly deals with setting standards, licensing and advancing Bluetooth capabilities. Before this it was standardized by the IEEE as IEEE 802.15.1, but since the SIG, that convention is not used. Here’s more about how the wireless communication standard came to be, why it is named so, how it has grown over the years and where it is used!
How Did Bluetooth Start and Why Is It Named So?
Originally conceived as an alternative to the popular RS-232 cables, Bluetooth was invented by telecom giant Ericsson in 1994. Supported by Intel, it then created the above mentioned body called the Bluetooth Special Interest Group that oversaw all development and licensing. For any company to use the standard or market products with the technology, they had to become a member of the SIG. As a result, the SIG is today over 20,000 members strong! However, not all members have the same power, there is a division called ‘Promoter Members’ for the ‘elite members’, so to speak. Members from this group have a say in the direction the company is going, and have generally had a hand in the development of the standard as a whole. The Promoter members are:
The Bluetooth Special Interest Group has a set of terms and conditions that must be followed by all members, and also has a set of compliance guidelines for all devices.
Now, to the very interesting name. Ericsson, the company that started Bluetooth is from Sweden, which is part of the Scandinavian region, a historical and cultural-linguistic part of Europe. The name comes from an epithet of a tenth-century King of Denmark and Norway named Harald “Bluetooth” Gormsson. In the local language, he was called Blåtand or Blåtann, which translated in English became ‘Bluetooth’. He was known for uniting the Vikings in ages past, from which the idea of the communication standard came, something that was a single unifying standard for mobile technologies. The logo, in fact, is a combination of two Nordic runes called ‘Hagall’ and ‘Bjarkan’, which were the initials of King Harald “Bluetooth” Gormsson.
How Does Bluetooth Work?
For the tech savvy, Bluetooth operates in the standard Industrial, Scientific and Medical (ISM) short range frequency band of 2.4 GHz. Specifically, it operated in the 2400–2483.5 MHz frequency band, which includes guard bands as well. It uses something called Frequency Hopping Spread Spectrum (FHSS), which is basically a multiple access method in which data packets are divided based on frequency over 79 designated Bluetooth channels. Each channel has a bandwidth of 1 MHz. The newer Bluetooth 4.0 standard, however, uses 2 MHz steps and thus has 40 designated channels. It uses a variation of FHSS called Adaptive Frequency-hopping spread spectrum (AFH), which theoretically skips channels with interference and results in better communication.
Bluetooth is essentially a protocol with a master-slave architecture, which means that one master device can communicate with up to 7 devices. This was and is a huge advantage to earlier wired communication protocols which could work only with a 1 to 1 configuration. Essentially creating a new standard called Personal Area Networks (PANs), Bluetooth brought about far more effective ad-hoc networks and allows communication without traditional host based networking. This network of Bluetooth devices is called a ‘piconet‘. There’s also work going on to create something called a ‘scatternet‘, which is a combination of two or more piconets, where a device that acts as a master in one piconet can be a slave in another.
Bluetooth Classes – Power Consumption and Range
Most Bluetooth devices have a range of around 10 meters or so, because they’re battery operated and are of the Class 2 type. Depending on power consumption and range, there are basically 3 types of Bluetooth devices. They are:
- Class 1: Max. Permitted Power – 100 mW, Range: Around 100 m
- Class 2: Max. Permitted Power – 2.5 mW, Range: Around 10 m
- Class 3: Max. Permitted Power – 1 mW, Range: Around 1 m
The huge drop in power from Class 2 to Class 1 is why the range is so short, but for daily use, 10 meters is more than enough. Larger applications and more powerful transceivers are where you can expect to see 100 meters range, and they are usually replacements for WiFi in certain situations where WLANs (Wireless Local Area Networks) are required. Although a line of sight is not always required for operation, a clear path is more or less recommended for optimum functioning. Like WiFi, walls and similar obstacles will decrease efficiency, more so since most devices aren’t meant for high range usage.
Bluetooth Versions Throughout the Years
Over the years, Bluetooth went from unknown network protocol to one of the most well known and commonly used standards in the world. Currently in v4.1, here’s how it has grown from strength to strength:
- Bluetooth v1.0: The first standard introduced, it wasn’t actually used commercially because it had difficulties with interoperability, which was supposed to be the main draw of a universal communication standard.
- Bluetooth v1.1: Dubbed IEEE 802.15.1-2002 since the SIG didn’t exist, it fixed a lot of the problems from the previous versions and added non-encrypted channels and signal strength indicators.
- Bluetooth v1.2: Brought about much faster transfer speeds, introduced AFH and better transmission conventions such as retransmission of corrupted data packets.
- Bluetooth v2.0+EDR: Again brought about faster transfer speeds, upto 3 Mbits/s theoretically. EDR stood for ‘Enhanced Data Rate’, to signify this.
- Bluetooth v2.1+EDR: A major revision that let device pairing happen much faster and more easily, as we know today.
- Bluetooth v3.0+HS: Another major revision that allowed data transfer of upto 24 Mbits/s, but not on the actual Bluetooth channel. The Bluetooth channel was used to pair devices, then the actual transfer was done over a channelized WiFi link.
- Bluetooth v4.0 LE: Called Bluetooth Low Energy, this drastically lowered power required while keeping data rates up, which opened up a whole new world of constantly connected devices such as fitness bands, smart watches and the like. It wasn’t possible earlier to keep the link on for too long because of battery and heat issues, so Bluetooth v4.0 LE was something of a milestone.
- Bluetooth v4.1: An evolution of v4.0, this version will support LTE transfers, higher exchange rates, better security protocols, efficient pairing and reduced network cycles.
Advantages and Disadvantages
As mentioned earlier, Bluetooth was something of a revolution, creating Personal Area Networks for easy sharing. Here’s some pros of Bluetooth technology:
- Easy to use
- Widespread and works across a range of devices
- Free ad-hoc networking
- Data transmission control
- Backwards compatible to a certain extent
- Does not require specific line of sight
Then, there are the cons:
- Somewhat vulnerable to hacking
- Loses connection after a certain short range
- Throughput can be affected in certain conditions
- Prone to wireless interference since it shares a common channel
- Slow transfer rates for heavy data usage
- Eats up battery power prior to the implementation of Bluetooth LE
Applications of Bluetooth
One thing’s for sure, however. Despite all the disadvantages or cons, Bluetooth is one of the most widely used network protocols in the world. While we are used to Bluetooth headsets, there’s way more to it than just that. Some of the applications include:
- Wireless headsets
- Interface between devices and in-vehicle entertainment systems
- Replacement for some WiFi networks
- Wireless bridging in corporate or industrial networks
- Wireless connection for peripherals like keyboards and mice
- Wireless audio transmission
- Videogame console controllers
- Low bandwidth wireless communication and data transfer
- Wireless interface between mobile devices and peripherals such as speakers
- Replacement for IR connections
- Short range medical applications
- Real time location tracking
- For personal security tracking (treasure tags)
Versatile would be an understatement for this network protocol. Commercial devices aside, Bluetooth is used all over the world in lesser known applications. It’s perhaps one of those standards that will go undisputed for years, if not decades to come, so might as well know more about it, right?