ULP Wireless Update

A short history of Bluetooth

The birth and commercialization of the ubiquitous short-range wireless technology was more protracted than you might think

Depending on who you ask, Bluetooth wireless technology’s history starts over one thousand years ago, in the Second World War, or in the early 90s.

Briefing Bluetooth

The idea for the Bluetooth name came from Jim Kardach of Intel, who was reading a historical novel about Vikings and King Harald Blåtand at the time. (Courtesy: Intel Free Press)


The name is the link to the distant past. “Bluetooth” is derived from the nickname of King Harald Blåtand a Dane who (somewhat violently) brought together warring factions in what are now Denmark, Norway, and Sweden into a single kingdom. King Harald reigned from 958 to 986 and got his nickname from his penchant for eating blueberries - although the less charitable claim his teeth were dyed blue from chewing the (presumably frozen) flesh of his slain enemies.


However, the frequency hopping spread spectrum (FHSS) technique upon which Bluetooth wireless technology bases its communication protocol is accredited to a patent issued in August 1942. Entitled “Secret Communication System,” the patent details a FHSS technique for a radio-controlled torpedo. Because the radio signals hopped across the radio spectrum, an enemy couldn’t jam the signal.


The most notable aspect of the patent – apart from the fact that the U.S. Navy didn’t follow it up because it mentions a piano keyboard as part of the explanation and the top brass thought that an actual musical instrument would have to be fitted into each weapon––is that it was taken out in the name of Hedwig Eva Maria Kiesler, better known as Hedy Lamarr, the beautiful Hollywood actress. Lamarr, together with co-inventor George Antheil, a pianist and Hollywood composer, first came up with the concept of frequency hopping. (It’s probably no coincidence given Antheil’s musical training that their system used 88 different carrier frequencies, equal to the number of keys on a piano.) (See ULP Wireless Q, Winter 2011 page 16.)


The birth of the SIG

But it is to 1994 that Bluetooth wireless technology really traces its roots. That year, Ericsson, the Swedish telecommunications company, came up with the idea of replacing the tangle of RS-232 cables that were then commonly used to communicate between instruments with an RF-based ‘wireless’ alternative.


Other companies including Intel and Nokia had also hit on the idea of wirelessly linking cellphones and computers at around the same time. In turn each company realised that to have any chance of universal interoperability (allowing products from different companies to connect because they used a common RF protocol) the technology would need to be standardised and driven by a Special Interest Group (SIG). The companies met at the Ericsson plant in Lund, Sweden, in December 1996 to agree on the formation of a SIG.


According to electronics trade magazine EETimes, it was at that meeting that the technology got its name when an Intel engineer called Jim Kardach suggested the codename “Bluetooth” seemed fitting. He explained that just as as King Harald had brought together warring tribes the companies would be uniting cellphones, computers, headsets and any other devices that could support a wireless link. The suggestion was that Bluetooth would continue to be used until the marketing people came up with something better. They never did. The Bluetooth logo also owes its formation to King Harald being made up of the runes (letters of the ancient Germanic alphabet used by the Danes) forming his initials.


The Bluetooth SIG was officially formed with five companies (Ericsson, Nokia, Intel, Toshiba, and IBM) in 1998 and Version 1 of the technology was launched a year later. By 2005, Version 2.0 (with Enhanced Data Rate) had been ratified, the SIG had welcomed its 4,000th member and shipments had reached 5 million per week (doubling just one year later).


Then in June 2007, the Bluetooth SIG acquired the Wibree Alliance, a Nokia-led initiative that included Nordic Semiconductor and which had set out to develop an ultra low power (ULP) form of wireless connectivity – using much less power the Bluetooth wireless technology – that could communicate with cellphones.


Nordic and others brought their expertise in ULP wireless connectivity to the SIG enabling it to develop a form of Bluetooth wireless technology – initially dubbed ultra low power Bluetooth and later Bluetooth low energy – that complemented the existing version but could run using coin cell batteries.


In 2010 the latest version of Bluetooth wireless technology, Version 4.0, (which included Bluetooth low energy as a hallmark element) was ratified and soon after the two types of chip described in the core specification - Bluetooth v4.0 and Bluetooth low energy ICs – became available.


Today, Bluetooth wireless technology is incorporated into billions of chips in thousands of applications, and Bluetooth low energy extends its usefulness to a huge new sector of devices powered by coin cell batteries. After nearly two decades of development, cumulative Bluetooth product shipments have passed 2.5 billion, membership has reached 19,000 and the technology is maturing into a product that has a very bright future indeed.