How there was mobile communication? Invention history. Influence of mobile communication on our life it is quite difficult to overestimate
. The huge number of people has a mobile device. He allows to be aware of many affairs and events: whether the relative is living whether the message came to e-mail...
But so was not always. Cellular communication was created not in one stage, its emergence was preceded by long development. It has the history.
It begins, strangely enough, on May 7, 1895. This day A.S. Popov carried out the first-ever broadcast. A year later the American scientist of the Yugoslavian origin Tesla gave radio signals already to 32 km.
The following and, perhaps, the most important should celebrate 1921. At this particular time the department of police of Detroit used the frequency of 2 MHz in the automobile system of a radio communication. Unfortunately, it worked only in one party. It was corrected in 30 - e years. The principle of amplitude modulation and bilateral systems of mobile communication were developed. In 1935 quality of the speech considerably improved thanks to the invention of the principle of frequency modulation. Same led also to emergence of more tiny equipment with smaller electricity consumption.
In 1947 the employee from Bell Laboratories reported on development of the concept of cellular communication. And already one year later the staff of the same laboratory invented the transistor which allowed to make all electronic equipment, turning on also devices of a radio communication, tiny.
And what at us in Russia? We did not lag behind other world too.
The first completely automatic duplex system of a professional mobile radio communication with mobile objects was developed in the USSR at the end of 50 - x years of the twentieth century. Quite long time “ Altai “ (so this system was called) was the only system of mobile communication in the country with an exit in a public telephone network.
Progress does not stand still, and in 1969 the Scandinavian countries came to the agreement on formation of special group for studying of areas of joint action in telecommunication and development of recommendations for this activity. There was the first international group of standardization in the field of mobile communication. The group was called NMT.
Work of experts was fruitful, and in 1973 they defined the properties allowing to carry out mobile communication both within one network and between networks. This property formed the roaming basis.
In 1981 the Swedish company Eriksson in Saudi Arabia put into operation the first-ever cellular communication on the basis of the analog NMT 450 standard.
Ten years later, in 1991, the first standard of digital communication was submitted. It is GSM. In seven years the number of subscribers of mobile communication reached 200 million worldwide. In a year the standard of a packet transmission of data of GPRS was issued. And in a year, in 2000, in Monaco, on the island Maine and in Sweden the first test 3G networks are built.
Here such long history at mobile communication. Nearly hundred years were required in order that from the first simple developments to pass to what we now with pleasure use.