Posts tagged Mobile

From the heavy cordless phones of the 1980′s to the smart phones of today, cellular phone technology has undergone a incredible change. But have you ever wondered how you can call to your well wisher in the whole world with the usage of a mobile phone? You also have knowledge about the main features such as WAP and GPRS from the cell phone vendors and service providers. But you must aware of what they really mean?

There are numerous mobile technologies. So next time, when you are going to purchase a phone, you should know what technologies it has.

Generations of mobile communications

In the late 1970s, the first generation (1G) of mobile communications was introduced; it was primarily used for voice transfer. Second generation (2G) systems came into existence in the early 1990s and was further developed to 2.5G, which includes high technologies such as TDMA, GSM and CDMA. These technologies were used for voice and data.

The next generation of mobile communications is 3G which delivers data speeds from 384 kbps to 2 Mbps and over wireless interfaces such as GSM, TDMA and CDMA.

Mobile phone access technologies

Frequency division multiple access (FDMA)
The first-generation analog mobile access method; for each call, FDMA uses separate frequencies. For instance, if there are four stations, each will receive their own frequency. So there is no interference between them. It reduces interference, but limits the number of users.

Time division multiple access (TDMA)
TDMA allocates unique time slots to each user within each channel, thus allowing many users to access the radio frequency without anyone’s interference. Each mobile conversation uses only a particular frequency slot of the time.

Code division multiple access (CDMA)
Commercially introduced in 1995 by Qualcomm, CDMA quickly became one of the world’s fastest-growing wireless technologies. 3G CDMA networks provide more capacity for voice traffic with high-speed data capabilities, hence many cellular service providers are now building or upgrading to it.

CDMA is used in both 2G and 3G wireless technologies. Indian Cell operators such as Reliance IndiaMobile, TATA Indicom, BSNL and MTNL’s Garuda all use CDMA2000 technology and its variant CDMA1x.

Global system for mobile communications (GSM)
GSM is now the worldwide standard technology for mobile communications. It is developed on TDMA protocol in Europe. GSM provides a high level of security, globally accepted technology standards and superior sound quality.

For any GSM phone to work, it needs a Subscriber Identity Module (SIM), a card which contains your telephone account information. So, an Indian GSM phone can be used in any part of the world.

Wireless technology platforms

1) GPRS
GPRS (General Packet Radio Services) is an enhancement to GSM technology that integrates GSM and IP technology. GPRS offers to access the Internet at the very high speed. So you can check your email on the move and surf the Web at very high speed. Currently BPL Mobile and Hutch (Orange in Mumbai) offer GPRS services in India.

2) WAP
In this high technology age, people on the move need any-time access to the Net. This is where WAP comes in. It facilitates us to Internet access from cell phones. It is an open standard for wireless protocols that is independent of the service providers. The cell phone must have a WAP browser to display Web content. Now-a-days, cell phones often come equipped with WAP browser and GPRS technology.
WAP and GPRS also enable the user to download games, send mail and even transfer your messages to your PC.

3) EDGE
The new EDGE (Enhanced Data GSM Environment) interface has been developed specifically to meet the bandwidth needs of 3G. This technology is promoted by Ericsson, it also offers high-speed data transfers over GSM networks with just a software upgrade to the handset. EDGE technology allows speeds up to 384 kbps.