The mobile phone is a miracle of the 21st century. This small device is not only a cheap means of communication with the whole world, but also a pocket computer. And therefore it can be both a universal working tool and a great entertainer. If the owner wants it and has some skill.
The greatness of the little mobile phone is also that it has changed both our character and our perception of the world. When making an appointment, you can allow yourself to not be too meticulous. And not too punctual. After all, you can always call and ask: “Where are you?” Now it will not work, as in the old song from the time of grandparents:
We were both there.
I'm at the pharmacy!
I was looking for you at the cinema!
So, tomorrow then
At the same place, at the same hour!
Impatience and boredom of waiting have also disappeared somewhere. There is no time to be bored at a public transport stop or on a trip. No one looks at fellow travelers. Everyone is busy with something, staring at a small screen: some are reading a book, some are checking the news on Facebook, some are watching a movie… To each according to their needs.
The mobile phone has changed the nature of users, but it has changed technical devices even more. Having torn off the cable tail, the phone has set off on a free flight and called all home appliances with it. Down with cables! Give us freedom of movement!
The history of the invention began with the idea of creating a new wireless technology standard that would allow mobile devices to exchange information with each other over short distances. Inventors from the Swedish company Ericsson began working in this direction in 1989.
The company manufactured mobile phones and wanted to produce wireless headphones for them. The idea was to use the radio frequency range from 2.4 to 2.485 Gigahertz for this purpose. This radio frequency range was provided by international agreements for use for non-broadcasting purposes. That is why it is called the ISM range (ISM is an abbreviation of three English words: Industry, Science, Medicine).
For example, microwave heating devices operate on this frequency – both household, industrial and medical. Obviously, if any radio station were to transmit on this wave, the powerful radiation of a working microwave oven would drown it out without a doubt. Another thing is that no commercial radio station will broadcast on such a frequency. This is a range of centimeter waves that spread within the line of sight and easily fade if any obstacle appears on their path, for example, a plaster, brick or concrete wall. But at short distances, within 10 meters, such radio communication would be ideal, if only because it does not require large energy costs.
However, if several transmitters operate nearby in this rather narrow frequency range, they will interfere with each other. The owner of one mobile phone will not hear “his” transmission, but can overhear the conversation of the person sitting next to him. How to combat this? And is it possible?
It turned out that it was possible. The idea was to split the narrow range of frequencies available for transmission into several sub-frequencies. The width of the permitted range is 2.485-2.4=0.085 Gigahertz or 85 Megahertz. In this interval, 79 working frequencies were allocated, each 1 Megahertz wide. Transmission at each working frequency lasts 625 microseconds. After which the receiver and transmitter simultaneously switch to another frequency. This frequency is chosen randomly according to a specific algorithm.
Thus, several receivers and transmitters working nearby will not interfere with each other. At the same time, each pair of “receiver-transmitter” encrypts the transmitted signal according to its own scheme. Therefore, even if a “foreign” receiver catches a signal from a “foreign” transmitter, it will not be able to decrypt it.
If the transmitted data were lost for some reason, they will be repeated during the next communication session, but at a different frequency and in a different encoding. An attempt to listen to the transmission will lead to nothing: noise will be heard, the frequency of which will be uniformly “smeared” across the entire width of the used range of 2.4-2.4835 GHz.
Before the start of transmission, the receiver and transmitter synchronize their work. They sort of agree on the algorithm by which they will change the transmission frequencies and signal encryption schemes. Then they work separately, but synchronously.
This method of radio communication is called the Frequency Hopping Spread Spectrum method and is abbreviated as FHSS. The FHSS method made it possible to organize the process of transmitting information via radio over short (up to 10 meters) distances. At the same time, the transmission channel itself is protected from interference and allows several clients to use it simultaneously. In addition, this method of wireless information transmission turned out to be easy to implement and did not consume much energy.
FHSS technology, the transmission protocol and the requirements that such devices must meet were developed by five Swedish engineers: Nils Rydbeck, Johan Ullman, Tord Wingren, Jaap Haartsen and Sven Mattisson .
The beautiful name for this technology, Bluetooth, was invented in 1998 by American Jim Kardach . How did this happen?
Several years have passed since the creation of wireless technologies based on radio communication have shown their convenience and reliability. It became clear that if they were integrated into laptops, the functionality of the latter would increase significantly. Now this seems almost obvious. But in 1996, even experts had to be convinced of this.
A Special Interest Group (SIG) was created for the joint work. This group included representatives from Ericsson, Nokia, Toshiba and IBM. These companies controlled more than 60% of the world's mobile phone and laptop production at the time. The SIG was to develop requirements for the universal, cheap, secure wireless radio communication system being created. The group was headed by Intel employee Jim Kardach.
All members of this group had their own interests and often competed. Therefore, Kardach found himself in the position of an arbitrator. Or better yet, a king, a unifier of warring clans and a mediator between them, so that the resulting union would be fruitful, combat-ready and successful.
This metaphor came to Jim Kardach's mind because at that time he was reading a historical novel about the adventures of the Vikings by the famous Swedish writer Frans Gunnar Bengtsson (1894-1954) . The novel was written in an entertaining, humorous manner and without much reverence for the heroic and bandit deeds of his ancestors.
The hero of the novel, a red-haired Viking named Orm, traveled around the world, as happened with the Vikings in the 10th century. He was captured and sold to Muslims. He was a slave to the ruler of Cordoba, and then ended up as a rower on the galleys, converted to Christianity and, in the end, was freed. What's more, Orm married the daughter of the konung (that is, king) Harald Bluetooth, which means he became – no more no less – a prince. At the end of the book, he even got rich, because in a sacred place, at the Dnieper rapids, he found a hidden treasure.
This novel was translated into Russian, and it is worth reading at least for the pleasure. Well, and to learn something new about the Vikings.
Kardach, for example, learned about King Harald Bluetooth (Harald BlГҐtan d ; 930-986?) . This fierce Viking united several previously independent clans under his rule and became the first king of Denmark and Norway. Moreover, he brought law and order to his kingdom, since he adopted Christianity. For this merit, he was later even canonized.
Jim Kardach, by his own estimation, found himself in a similar situation. He had to humble and unite representatives of independent and powerful companies, and also to establish law and order, developing common specifications for the upcoming product. Not suffering from delusions of grandeur, he treated his “royal” position with humor.
At that moment, the participants of the joint group could not come up with a single name for the common project. Each of the participating companies had its own development for providing radio communication between a mobile phone and a laptop, and these developments were called differently. Using his rights as a leader, Jim Kardach suggested as a temporary name for the project the nickname of the warlike Harald – Blue Tooth, in English “Bluetooth”.
There is nothing more permanent than the temporary. The band members never came up with a new name for the project they were working on. Moreover, when it was time to write the final documentation, it turned out that everyone had already gotten used to the stupid name “Blue Tooth” and decided not to change it. Moreover, the logo for the intercomputer connection was made up of two runes – Hagalaz (бљј) and Berkana (б›'), which were the beginning of the name and nickname of the Viking king. Thus, Harald Bluetooth entered the 21st century.
You could say he was canonized for the second time. Who would remember him, the blue-toothed one, now? And everyone knows Bluetooth!
