what is 2g ?

The 2G Technology 

2G refers to second generation wireless telecommunication technology. While its predecessor, 1G, made use of analog radio signals, 2G uses digital radio signals.

Based on what type of multiplexing (the process of combining multiple digital data streams into one signal) is employed, 2G technologies may be categorized by whether they are based on time division multiple access (TDMA) or code division multiple access (CDMA).


TDMA-based 2G standards include the following: Global System for Mobile communications (GSM), used worldwide; Integrated Digital Enhanced Network (IDEN), developed by Motorola and used in the United States and Canada; Interim Standard 136 (IS-136) or Digital Advanced Mobile Phone System (D-AMPS), used in North and South America; and Personal Digital Cellular (PDC), used in Japan.
IS-95, on the other hand, is CDMA-based. It was developed by Qualcomm, and is alternately known as TIA-EIA-95 or cdmaOne.

2G makes use of a CODEC (compression-decompression algorithm) to compress and multiplex digital voice data. Through this technology, a 2G network can pack more calls per amount of bandwidth as a 1G network. 2G cellphone units were generally smaller than 1G units, since they emitted less radio power.

Another advantage of 2G over 1G is that the battery life of a 2G handset lasts longer, again due to the lower-powered radio signals. Since it transmitted data through digital signals, 2G also offered additional services such as SMS and e-mail. Its lower power emissions also made 2G handsets safer for consumers to use.

Error checking, a feature allowed by digital voice encoding, improved sound quality by reducing dynamic and lowering the noise floor. Digital voice encoding also made the calls less susceptible to unwanted eavesdropping from third parties, due to the use of radio scanners.

Another use of this technology is the availability of international emergency numbers, which can be used by international users anytime without having to know the local emergency numbers. PDC or personal digital cellular technology was developed in Japan, and is exclusively used in JAPAN as well. PDC uses 25 KHz frequency. Docomo launched its first digital service of PDC in 1993.integrated digital enhanced network (iDEN) was developed by MOTOROLA, as a major mobile technology. It enabled the mobile users to make use of complex trunked radio and mobile phones. iDEN has a frequency of about 25Khz.i DEN allows three or six user per mobile channel.iS-136 is a second generation cellular phone system. It is also known as digital AMPS. D-AMPS were widely popular in America and Canada. However now it is in the declining phase. This technology is facing a strong competition by GSM technologies.  Now the network carriers have adopted GSM and other CDMA 2000 technologies at large. Interim standard 95 is a first and the foremost CDMA cellular technology. It is most famous by its brand name known as cdmaOne. It makes use of the CDMA to transfer the voice signals and data signals from cellular phones to cell sites (cell sites is cellular network).

Benefits of 2G technology (Second Generation)

Digital signals require consume less battery power, so it helps mobile batteries to last long. Digital coding improves the voice clarity and reduces noise in the line. Digital signals are considered environment friendly. The use of digital data service assists mobile network operators to introduce short message service over the cellular phones. Digital encryption has provided secrecy and safety to the data and voice calls. The use of 2G technology requires strong digital signals to help mobile phones work. If there is no network coverage in any specific area, digital signals would be weak.