Almost all people in the world know mobile phone. Mobile phone
is a portable telephone that can make and receive calls over a radio frequency
carrier while the user is moving within a telephone service area. In my opinion,
mobile phone, especially smartphone is important in our life because it is help
our work. It’s help us to keeping in touch with family member and friends, help
our business, and for entertainment. With smartphones, we also can access the
internet.
Martin Cooper of Motorola made the first publicized handheld
mobile phone call on a prototype DynaTAC model on April 4, 1973. The first
commercial automated cellular network was launched in Japan by Nippon Telegraph
and Telephone in 1979. This was followed in 1981 by the simultaneous launch of
the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and
Sweden. These first-generation (1G) systems could support far more simultaneous
calls, but still used analog technology. In 1991, the second-generation (2G)
digital cellular technology was launched in Finland by Radiolinja on the GSM
standard.
Ten years later, in 2001, the third generation (3G) was
launched in Japan by NTT DoCoMo on the WCDMA standard. This was followed by
3.5G, 3G+ or turbo 3G enhancements based on the high-speed packet access (HSPA)
family, allowing UMTS networks to have higher data transfer speeds and
capacity. By 2009, it had become clear that, at some point, 3G networks would
be overwhelmed by the growth of bandwidth-intensive applications, such as
streaming media. Consequently, the industry began looking to data-optimized
fourth-generation technologies, with the promise of speed improvements up to
ten-fold over existing 3G technologies. The first two commercially available
technologies billed as 4G were the WiMAX standard, offered in North America by
Sprint, and the LTE standard, first offered in Scandinavia by TeliaSonera.
Mobile phone use while driving, including talking on the
phone, texting, or operating other phone features, is common but controversial.
It is widely considered dangerous due to distracted driving. Being distracted
while operating a motor vehicle has been shown to increase the risk of
accidents. In September 2010, the US National Highway Traffic Safety
Administration (NHTSA) reported that 995 people were killed by drivers
distracted by cell phones.
Mobile phones are commonly used to collect location data.
While the phone is turned on, the geographical location of a mobile phone can
be determined easily (whether it is being used or not) using a technique known
as multilateration to calculate the differences in time for a signal to travel
from the mobile phone to each of several cell towers near the owner of the
phone. The movements of a mobile phone user can be tracked by their service
provider and, if desired, by law enforcement agencies and their governments.
Both the SIM card and the handset can be tracked.
The effect of mobile phone radiation on human health is the
subject of recent interest and study, as a result of the enormous increase in
mobile phone usage throughout the world. Mobile phones use electromagnetic radiation
in the microwave range, which some believe may be harmful to human health.