Cellular phones

In the last two decades, wireless communication systems such as cordless phones, paging systems, wireless data networks, satellite-based and cellular mobile systems have been steadily increasing in both popular importance and technological sophistication. The firstgeneration wireless systems were developed in the late 1970s and 1980s and were based on analog technology (such as the Advance Mobile Phone Service (AMPS) by AT&T and Nordic Mobile Telephone (NMT) by Ericsson).

26p tienvovan 11-09-2010 61 5   Download

SAR Distributions in a Head Model The development of cellular telephones and mobile communication systems has led to a growing awareness of the vital role that wireless systems play in communication networks and the biological effects of EM fields on users. Since cellular hand phones are operated in close proximity to human heads while in use, there has been increasing public concern about the health effects of the human head exposed to EM energy emitted from mobile handset antennas.

36p tienvovan 11-09-2010 85 13   Download

The Future is Wireless A Typical Day in the Year 2000 Joe Mobilus is a manager with a haulage firm in a city 100 km away from his home town; his wife Sue is a nurse at the local hospital. Their son Tom and daughter Ann are still at school. 06:30 The central alarm system wakes Joe and Sue in line with their weekly schedule. 07:00 Joe uses his TETRA terminal to access his firm’s central computer to see if there have been any changes to his diary. 07:15 Joe leaves his house and using his cellular phone in the...

4p huggoo 20-08-2010 48 2   Download

Hello, in this module we are going to discuss wireless networking. Specifically, we'll take a look at how wireless technology works, how it is commonly deployed, and the security issues associated with using it. Because wireless communications can penetrate opaque objects such as buildings, the risk of someone accessing a private network increases markedly. With wireless, an attacker does not need to gain access to physical cables or jacks, but only needs to have an antenna and be within range of the transmissions....

40p huyhoang 07-08-2009 211 74   Download