4G
systems was originally visioned by Defence Advanced Research Projects
Agency (DARPA). The DARPA selected the distributed architecture and end
to end internet protocol (IP). They believed in an early age, in peer
to peer networking in which every mobile device would be both a
transreceiver and a router for other devices in the network ,this
eliminates the need of spoke and the hub which are the weakness of 2g
and 3g cellular systems.
The traditional voice calling is replaced by IP telephony in 4g systems. The specifications of 4G named as International Mobile Technology Advanced (IMT-A) was proposed by International Telecommunication Union Radio (ITU-R). The main aim of developing this technology is speed requirements of 100 mbps for high mobility such as users in trains and a speed of 1 gbps for stationary users. The basic idea behind 4G is to use only packet switching and internet protocol based communication.
The spread spectrum technique which is used in 3G is replaced by OFDMA in order to achieve desired speed.In order to fulfill these requirements pre 4G was launched which are the technologies named as LTE and wimax. The 1st vision of 4g with ITU was laid in 2002. In 2008, HTC announced first Wimax enable mobile as MAX 4G. Unfortunately, these technologies are not able to meet the requirements of 4g as desired.
In feb 2007, NTT DOCOMO the japanese company tested 4g and was able to achieve maximum packet transmission at a rate of 5gbps. LTE advanced offering a downloading speed of 1 gbps and uploading speed of 500 mbps. In April 2012, Bharti Airtel is the company which successfully launched 4G first time in India. In dec 2012, telcel launched 4G LTE in nine major cities of Mexico.
The traditional voice calling is replaced by IP telephony in 4g systems. The specifications of 4G named as International Mobile Technology Advanced (IMT-A) was proposed by International Telecommunication Union Radio (ITU-R). The main aim of developing this technology is speed requirements of 100 mbps for high mobility such as users in trains and a speed of 1 gbps for stationary users. The basic idea behind 4G is to use only packet switching and internet protocol based communication.
The spread spectrum technique which is used in 3G is replaced by OFDMA in order to achieve desired speed.In order to fulfill these requirements pre 4G was launched which are the technologies named as LTE and wimax. The 1st vision of 4g with ITU was laid in 2002. In 2008, HTC announced first Wimax enable mobile as MAX 4G. Unfortunately, these technologies are not able to meet the requirements of 4g as desired.
In feb 2007, NTT DOCOMO the japanese company tested 4g and was able to achieve maximum packet transmission at a rate of 5gbps. LTE advanced offering a downloading speed of 1 gbps and uploading speed of 500 mbps. In April 2012, Bharti Airtel is the company which successfully launched 4G first time in India. In dec 2012, telcel launched 4G LTE in nine major cities of Mexico.
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