Now a day we find out that mobile phone is really one of the necessary parts in our daily life for the different types of application. We also find that during the last decade the mobile phone became very ordinary and all types of person easily access it. The technology platform has also moved on from “voice to wireless information”. The mobile technology revolution is less than twenty years old and the entire history of “mobile radio” is barely 100 years old.
Mobile phone is the new revolutionary part of the science in the modern technology concern. If we look back about the mobile technology then we see that second half of the 19th century the wireline telegraphy and telephony changed the nature of communication process. Within some days or some year we receive the movement of material had gone from the speed of people to the speed of light. After that in the 20th century the second revolution took place as well as the radio freed those same communications from the constraint of a wire. Radio waves have almost mystic goods that capture the imagination and lead to a variety of different uses. Travelling through our atmosphere or the universe, they attach ideas that could be attached in no other way. Travelling at a known speed which allows us to locate flying objects, determine our own location on the surface of the earth, and even chart the universe.
It passes through many solids, and fills in behind obstructions through the mechanisms of reflection and diffraction, so that the information it carries is available “everywhere” throughout a large area of coverage. As a result we notice that millions of people can access and share the same “broadcast” news and entertainment at very low cost with contiguous process. This property of the radio waves that we have described as “filling space” leads not only to broadcast, but to the last and newest form of radio communications. Basically it allows us to reach a particular person at any time and any location since the antenna can move through that space while sending or receiving the signal, it also makes “mobile communications” possible.
The Origins of Mobile Communications:
In the year of 1860 most probably middle of the age, the Scottish mathematician James Clerk Maxwell formed a pair of mathematical equations (Theorem) whose explanation anticipated electromagnetic (charging the metal body which convert magnetic media) waves transmitting at the speed of light. It took 20 years to verify this prediction in the laboratory, and another 20 years for the first “mobile” application to take place. In the year of 1899, Guglielmo Marconi ushered in the era of practical mobile radio communication with his historical radio telegraph transmissions from a ship in New York Harbor to the Twin Lights in Highlands New Jersey. His first transmission covered the arrival of Admiral Dewey from Manila, and soon thereafter, coverage of the Americas Cup races was provided as well. This was accomplished with high energy, wideband pulses of radio noise, created using a spark generator coupled to an antenna. The signal was received with a similar antenna attached to a fascinating device. That device is also known as a “coherer,” a tube in which metallic particles were caused to cohere to one another by the presence of the radio signal.
After one year, Marconi had added filtering to create separable channels, and thus to allow multiple simultaneous transmissions in the same area. After three years, he was able to cross the Atlantic with a radio transmission, and radio telegraphy was soon used on many ocean-going receptacles in year of 1929. At that movement radios were small and rugged enough to be installed in automobiles, and the first “land mobile” radio system was put into operation by the Detroit police in 1928.
Early Mobile Proposals:
The origin of mobile lies surprisingly deep in the past. In 1947, essentially the same time that the first 150 MHz system was installed in St Louis, the Bell System (AT&T) proposed a “broadband urban mobile system”. At that movement requested 40 MHz for its implementation somewhere in the region among 100 and 450 MHz. At that time, the idea that a large geographic area could be served using many small coverage areas which had already been put forward at Bell Laboratories, mainly to allow low-power radios to be used. The FCC denied this request, citing the unavailability of frequencies in that range. In the year of 1949, the FCC considered allocation of the band from 470 to 890 MHz, but chose to reserve this band for the vast enlightening and entertainment chances assumed to be offered by the newly proposed UHF (Ultra high frequency) TV band. After some period in the year of 1958, the Bell System requested an allocation for mobile telephone and this time in the range of 764-840 MHz, and after that once again the FCC declined to take action.
The Transition to Digital Cellular Systems:
When the cellular systems are deploying with very fast way at the first decade of service used digital signals for controlling the process, but the voice signal was carried as an “analog” waveform. As well as in the year 1970s, there was an early debate as to the potential advantages of a fully digital system. In this situation it was determined the technology was not ready for a fully digital cell phone that would achieve the same spectrum efficiency whereas voice quality and cost as the analog design, but if we look at late 1980s this was quickly changing. This primary reason was that voice processing technology, using digital signal processing (DSP) chips, had made dramatic advances. Good quality voice, once requiring 30-60,000 bits per second which was becoming possible at rates approaching 10,000 bits per second. This was allowed three times as many voice channels to be created from the same spectrum, which had significant cost-effective consequences.
The Cost of Spectrum:
Spectrum is the very popular part in the mobile technology, while spectrum at 800 and 900 MHz has proved very desirable for mobile purposes, and spectrum at 2-3 GHz has now been used as well, higher frequencies pose significant problems in terms of broadcast and path loss. At higher frequencies, antennas are smaller and capture less received signal, and the ability of the signal to bend (diffract) around the corners and over hills is reduced. As wavelengths are reduced to inches and less the scattering by foliage and even raindrops takes place as well as 2-3 GHz, systems must inaugurate with smaller cells, raising significantly their initial costs.
Concept of creating the Wireless Internet:
Given the acceptance of mobile voice communications and the Internet that seems inevitable that they will soon merge in what has been called the wireless Internet. Normally email and Internet-based services have been offered in current second-generation mobile systems, with market results that have often fallen short of opportunities. This may be because the pocket phones that are most popular have small screens with limited keypads and small batteries. It may also be that these initial service offerings have not been sufficiently exciting to the mobile customer. It is certainly true that the bit-rates offered have been rather low, and the cost of delivering those bits has been rather high, when we compared to the fast modems and flat-rate services of the “wireline Internet.”
Different Standards Used in Different Generations of Mobile Technologies:
Following table will give the real demonstration of the all types of mobile technology we must compare with all generation (1St Generation, 2nd Generation, and 3rd Generation) of mobile technology as table format.
|1. Paging systems||1. Paging systems||1. Single standard under IMT-2000, UMTS, MC-CDMA, TD-SCDMA|
|2. Cordless telephone||2. Cordless telephone (DECT, PACS)|
|3. Cordless telephone cell||3. WLL|
|4. Private mobile radio||4. Private mobile radio (TETRA)|
|5. Mobile systems (NMT, AMPS, etc)||5. Mobile systems (GSM, D-AMPS,PDC, IS-95)|
|6. Mobile satellite systems||6. Mobile satellite systems(IRIDIUM, ICO,GLOBALSTAR)|
Table 1: Showing comparison
It is no doubt that mobile system has a gigantic and extraordinary role in our modern science as well as media science. This Science is now not only base on the hardware but also base with software and operating system. We should have clear idea about all types of background knowledge of the mobile technology. This mobile technology is based on radio wave and from this mobile communication has started their journey.