What is Bluetooth and How Was it Discovered?
Bluetooth, in a nutshell, is a wireless technology protocol for transmitting data over short distances between fixed and mobile devices. Nils Rydbeck of Ericsson Mobile in Lund, Sweden, was the first to create the “short-link” radio technology, which was later dubbed Bluetooth, in 1989. Ericsson’s short-link technology was first integrated into a ThinkPad notebook and an Ericsson phone when the technology was first launched. Since neither IBM ThinkPad notebooks nor Ericsson phones were market share leaders at the time, they decided to make the short-link technology an open business standard to give each player full market access. The Bluetooth SIG was founded in May 1998, with IBM and Ericsson as founding members and a total of five members: Ericsson, Intel, Nokia, Toshiba, and IBM. The Bluetooth SIG now has over 35,000 members in the telecommunications, engineering, networking, and consumer electronics industries.
Why is it Called Bluetooth?
▲ Bluetooth Logo [2]
The name Bluetooth is an Anglicized variant of the Scandinavian Blåtand/Blåtann, which is the epithet of Harald Bluetooth, a tenth-century Danish king who brought disparate Danish tribes together to form a common kingdom. Bluetooth, it is implied, unifies connectivity protocols. The Bluetooth emblem is a bind rune that combines King Harald’s initials. (ᚼ, Hagall and ᛒ, Bjarkan).
How Does it Work?
Firstly, Bluetooth differs from WiFi and cellular data in that Bluetooth devices connect directly with one another rather than routing traffic via an intermediary system like a wireless router or cell towers. This makes life much easier and keeps power consumption to a minimum, extending battery life at the cost of range and data rates.
Secondly, as of 2020, there are two types of Bluetooth technology: Bluetooth Low Energy (LE) and Bluetooth Classic. While both use the same frequency range, Bluetooth LE is by far the more common alternative. It uses much less energy to run and can be used for broadcast or mesh networks in addition to facilitating contact between two users over point-to-point connections.
Classic Bluetooth technology has a significantly higher data rate than Bluetooth LE (3 Mbs vs. 1 or 2 Mbs), but it can only be used for direct communication between two computers over point-to-point connections. Each of the two forms of Bluetooth technology has its own set of advantages, and manufacturers choose the one that better suits their product’s requirements.
▲ Types of bluetooth connection [6]
Both devices must also have an antenna-supplied chip that can encrypt, decrypt, and relay data through an antenna in order for Bluetooth communication to operate. Pinging signals in the form of radio waves are sent out by the user with the final source, such as a speaker, and can be heard by other bluetooth devices. Bluetooth systems communicate using low-power radio waves in the 2.400 GHz to 2.483.5 GHz frequency range. This is one of only a few bands designated for the use of industrial, scientific and medical devices (ISM) by international agreement.
A personal-area network (PAN) or piconet is formed when Bluetooth peripherals are attached to the same central computer and extend a distance of less than 15 meters. If a piconet is formed, its members hop radio frequencies in unison (1600 hops per second) to keep in contact with one another and avoid interference with other Bluetooth piconets in the same space or devices using other wireless technology including WiFi. The physical radio channel in a piconet is shared by a group of devices synchronized to a standard clock and frequency-hopping pattern, with the master node supplying synchronization references. This mechanism, known as adaptive frequency hopping, enables Bluetooth devices to function even in environments with a large number of wireless devices.
How Can Radio Frequencies Transmit Information?
Ok, so now we understand how Bluetooth works, but I’m sure you want to know how it really works. Instead of analog signals, Bluetooth uses what is known as optical signal processing. Logic signals, also known as binary signals, are a simplified representation of digital signals. They are expressed by two voltage bands: one near a reference value (usually ground or zero volts) and the other near the supply voltage.
▲ Graph of digital signals using different amplitude [5]
Digital signals can take on various degrees or amplitudes with more sophisticated signalling, allowing for a much more complicated mechanism to relay information.
▲ Digital signals using voltage [5]
FSK, or frequency-shift keying, is used by Bluetooth to take it a step further. This is analogous to increasing the amplitude, but instead of using two or three distinct frequencies to hold different states, it uses two or more more frequencies to hold different values.
▲ Simplified diagram of FSK [5]
FSK, or frequency-shift keying, is used by Bluetooth to take it a step further. This is analogous to increasing the amplitude, but instead of using two or three distinct frequencies to hold different states, it uses two or more more frequencies to hold different values.
▲ Simplified diagram of FSK [5]
FSK may also be used to describe more distinct values by transmitting information at higher frequencies. Furthermore, Bluetooth technology makes use of a more complex phase shifting scheme, which allows for a wider range of values that each wave can take on. When both of the components are integrated, bluetooth radio waves can express a wide range of data sequences, allowing for even higher transfer speeds.
Summary
Bluetooth is a highly adaptable interface that can be used for a variety of purposes, including home appliances and consumer electronics, medical devices such as stethoscopes, pacemakers, and glucose meters, and third-party communications such as Apple’s Airdrop. With the contacts you make with bluetooth peripherals, you will build an environment where frequencies are not disrupted by hopping radio signals. Bluetooth can send data/information to these radio waves by adjusting amplitude, frequency, phase changes, and other variables that the receiver can decipher.
[1] A Science Odyssey: Radio Transmission: FM vs AM. (2021). Pbs.org. https://www.pbs.org/wgbh/aso/tryit/radio/radiorelayer.html
[2] Bluetooth® Technology Website. (2019). Bluetooth® Technology Website. https://www.bluetooth.com/
[3] How does Bluetooth work? (2007, November 5). Scientific American. https://www.scientificamerican.com/article/experts-how-does-bluetooth-work/
[4] John, S. (2020, May 20). “What is Bluetooth?”: A beginner’s guide to the wireless technology. Business Insider; Business Insider. https://www.businessinsider.com/what-is-bluetooth
[5] Wikipedia Contributors. (2021, February 9). Digital signal. Wikipedia; Wikimedia Foundation. https://en.wikipedia.org/wiki/Digital_signal
[6] Laxmi Ashrit. (2019, January 2). Bluetooth 5 Technology – Protocol Stack, Network Topology, Applications. Electricalfundablog.com; electricalfundablog.com. https://electricalfundablog.com/bluetooth-5-technology/
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