mobile devicesmobile devices

History & Future

history It can be said that the mobile devices

was born at the same time the radio communication had been invented.

The development of mobile devices starts from the 1920's, there are five stages.

Stage One 1920's-1940's Based on several wave bands of shortwave, the

private mobile communication system had been invented.

The Detroit police car radio system is the representative one.

The frequency of this system is 2MHz at that time. In the 1940's the frequency had been risen to 30~40MHz.

It is considered as the beginning of the modern mobile service.

Stage Two

1940's-1960's

The public mobile service came out. 1946 According to the plan of Federal Commu

nications Commission(FCC) the Bell system established the first public car phone net in St.Louis.

There was three channles in that time, the mode was simplex.

Stage Three1960's-1970's

America improved the mobile telephony system(1MTS)

This period complete : automatic channel choose automatic dialing to the net

Stage Four1970's-1980's( the peak time)

The Bell Labs successfully developed the advanced mobile phone system(AMPS)

The cellular network built up, improved the capacity of the system.

The cellular network becames the utility system, used in the worldwide.

Stage FourAchivements in this stage: microelectronic technique got a significant

development which made the probability of miniaturization mobile devices be true.

The new system of mobile communication----cellular network

provide the technique for the manage and control of the large size net

Stage Five1980's- The Digital Mobile Communication

System(DMCS) gets developed and mature in this period.

AMPS & TACS stand for the Cellular Networks Ⅰ→analog system

Future The mobile devices plays an indispensable r

ole in nowaday's life, meanwhile this field is still rapidly developing. More app is going to be added into.

In 2004 July 16, Japanese telephone company NTT DoCoMo announced the P605iC phone which carried the FeliCa soft. This phone opened the curtain of No Cards Generation.

Future

Nowadays the manufactures of mobile devices are devoting on touching screen and 3D effect.

More and more APP will be added into the mobile devices, make people's life much more convenient and fun.