History of 4G and pre-4G technologies
The 4G system was originally envisioned by the Defense Advanced Research Projects Agency (DARPA).[citation needed[->0]] The DARPA selected the distributed architecture and end-to-end Internet protocol (IP), and believed at an early stage in peer-to-peer networking in which every mobile device would be both a transceiver and a router for other devices in the network, eliminating the spoke-and-hub weakness of 2G and 3G cellular systems.[33][page needed[->1]] Since the 2.5G GPRS system, cellular systems have provided dual infrastructures: packet switched nodes for data services, and circuit switched nodes for voice calls. In 4G systems, the circuit-switched infrastructure is abandoned and only a packet-switched network[->2] is provided, while 2.5G and 3G systems require both packet-switched and circuit-switched network nodes[->3], i.e. two infrastructures in parallel. This means that in 4G, traditional voice calls are replaced by IP telephony.
· In 2002, the strategic vision for 4G—which ITU[->4] designated as IMT-Advanced—was laid out.
· In 2005, OFDMA[->5] transmission technology is chosen as candidate for the HSOPA[->6] downlink, later renamed 3GPP Long Term Evolution (LTE) air interface E-UTRA[->7].
· In November 2005, KT[->8] demonstrated mobile WiMAX service in Busan, South Korea.[34]
· In April 2006, KT[->9] started the world's first commercial mobile WiMAX service in Seoul, South Korea.[35]
· In mid-2006, Sprint Nextel[->10] announced that it would invest about US$5 billion in a WiMAX[->11] technology buildout over the next few years[36] ($5.76 billion in real[->12] terms[37]). Since that time Sprint has faced many setbacks that have resulted in steep quarterly losses. On 7 May 2008, Sprint[->13], Imagine[->14], Google[->15], Intel[->16], Comcast[->17], Bright House[->18], and Time Warner[->19] announced a pooling of an average of 120 MHz of spectrum; Sprint merged its Xohm[->20] WiMAX division with Clearwire[->21] to form a company which will take the name "Clear".
· In February 2007, the Japanese company[->22] NTT DoCoMo[->23] tested a 4G communication system prototype with 4×4 MIMO[->24] called VSF-OFCDM[->25] at 100 Mbit[->26]/s while moving, and 1 Gbit[->27]/s while stationary. NTT DoCoMo completed a trial in which they reached a maximum packet transmission rate of approximately 5 Gbit/s in the downlink with 12×12 MIMO using a 100 MHz frequency bandwidth while moving at 10 km/h,[38] and is planning on releasing the first commercial network in 2010.
· In September 2007, NTT Docomo demonstrated e-UTRA data rates of 200 Mbit/s with power consumption below 100 mW during the test.[39]
· In January 2008, a U.S. Federal Communications Commission[->28] (FCC) spectrum auction[->29] for the 700 MHz former analog TV frequencies began. As a result, the biggest share of the spectrum went to Verizon Wireless and the next biggest to AT&T.[40] Both of these companies have stated their intention of supporting LTE[->30].
· In January 2008, EU commissioner Viviane Reding[->31] suggested re-allocation of 500–800 MHz spectrum for wireless communication, including WiMAX.[41]
· On 15 February 2008, Skyworks Solutions released a front-end module for e-UTRAN.[42][43][44]
· In November 2008, ITU-R[->32] established the detailed performance requirements of IMT-Advanced, by issuing a Circular Letter calling for candidate Radio Access Technologies (RATs) for IMT-Advanced.[45]
· In April 2008, just after receiving the circular letter, the 3GPP organized a workshop on IMT-Advanced where it was decided that LTE Advanced, an evolution of current LTE standard, will meet or even exceed IMT-Advanced requirements following the ITU-R agenda.
· In April 2008, LG and Nortel demonstrated e-UTRA data rates of 50 Mbit/s while travelling at 110 km/h.[46]
· On 12 November 2008, HTC[->33] announced the first WiMAX-enabled mobile phone, the Max 4G[->34][47]
· In 15 December 2008, San Miguel Corporation[->35], the largest food and beverage conglomeratein southeast Asia, has signed a memorandum of understanding with Qatar Telecom QSC (Qtel[->36]) to build wireless broadband and mobile communications projects in the Philippines. The joint-venture formed wi-tribe Philippines, which offers 4G in the country.[48] Around the same time Globe Telecom[->37] rolled out the first WiMAX service in the Philippines.
· On 3 March 2009, Lithuania's LRTC announcing the first operational "4G" mobile WiMAX[->38] network in Baltic states.[49]
· In December 2009, Sprint began advertising "4G" service in selected cities in the United States, despite average download speeds of only 3–6 Mbit/s with peak speeds of 10 Mbit/s (not available in all markets).[50]
· On 14 December 2009, the first commercial LTE deployment was in the Scandinavian capitals Stockholm[->39] and Oslo[->40] by the Swedish-Finnish network operator TeliaSonera[->41] and its Norwegian brandname NetCom (Norway)[->42]. TeliaSonera branded the network "4G". The modem devices on offer were manufactured by Samsung[->43] (dongle GT-B3710), and the network infrastructure created by Huawei[->44] (in Oslo) and Ericsson[->45] (in Stockholm). TeliaSonera plans to roll out nationwide LTE across Sweden, Norway and Finland.[51][52] TeliaSonera used spectral bandwidth of 10 MHz, and single-in-single-out, which should provide physical layer net bitrates[->46] of up to 50 Mbit/s downlink and 25 Mbit/s in the uplink. Introductory tests showed a TCP[->47] throughput[->48] of 42.8 Mbit/s downlink and 5.3 Mbit/s uplink in Stockholm.[53]
· On 25 February 2010, Estonia's EMT[->49] opened LTE "4G" network working in test regime.[54]
· On 4 June 2010, Sprint Nextel[->50] released the first WiMAX smartphone in the US, the HTC Evo 4G[->51].[55]
· In July 2010, Uzbekistan[->52]'s MTS[->53] deployed LTE in Tashkent[->54].[56]
· On 25 August 2010, Latvia[->55]'s LMT[->56] opened LTE "4G" network working in test regime 50% of territory.
· On November 4, 2010, the Samsung Galaxy Craft offered by MetroPCS[->57] is the first commercially available LTE smartphone[57]
· On 6 December 2010, at the ITU World Radiocommunication Seminar 2010, the ITU[->58] stated that LTE[->59], WiMax[->60] and similar "evolved 3G technologies" could be considered "4G".[5]
· On 12 December 2010, VivaCell-MTS launches in Armenia[->61] a 4G/LTE commercial test network with a live demo conducted in Yerevan[->62].[58]
· On 28 April 2011, Lithuania[->63]'s Omnitel[->64] opened a LTE "4G" network working in the 5 largest cities.[59]
· In September 2011, all three Saudi telecom companies STC[->65], Mobily[->66] and Zain[->67] announced that they will offer 4G LTE for USB modem dongles, with further development for phones by 2013.[60]
· In 2011, Argentina[->68]'s Claro[->69] launched a 4G HSPA+ network in the country.
· In 2011, Thailand[->70]'s Truemove-H[->71] launched a 4G HSPA+ network with nation-wide availability.
· On March 17, 2011, the HTC Thunderbolt[->72] offered by Verizon in the U.S. was the second LTE smartphone to be sold commercially.[61][62]
· On 31 January 2012, Thailand[->73]'s AIS[->74] and its subsidiaries DPC[->75] under cooperation with CAT Telecom[->76] for 1800 MHz frequency band and TOT[->77] for 2300 MHz frequency band launched the first field trial LTE in Thailand with authorization from NBTC[->78].[63]
· In February 2012, Ericsson[->79] demonstrated mobile-TV[->80] over LTE, utilizing the new eMBMS service (enhanced Multimedia Broadcast Multicast Service[->81]).[64]
· On 10 April 2012, Bharti Airtel[->82] launched 4G LTE[->83] in Kolkata[->84], first in India[->85].[65]
· On 20 May 2012, Azerbaijan's biggest mobile operator Azercell[->86] launched 4G LTE[->87].[66]
· On 10 October 2012, Vodacom (Vodafone South Africa) became the first operator in South Africa to launch a commercial LTE service.
· In December 2012, Telcel launches in Mexico[->88] the 4G LTE network in 9 major cities
· In the republic Kazakhstan on December 26, 2012 is launches the network LTE 4G in the entire territory in the frequency bands 1865-1885/1760 - 1780 MHz for the urban population and in 794-799/835-840 MHz for those sparsely populated
[edit[->89]]

3G, short for third Generation, is a term used to represent the 3rd generation of mobile telecommunications technology. Also called Tri-Band 3G. This is a set of standards used for mobile devices[->90] and mobile telecommunication[->91] services and networks that comply with the International Mobile Telecommunications-2000 (IMT-2000) specifications by the International Telecommunication Union[->92].[1] 3G finds application in wireless voice telephony[->93], mobile Internet[->94] access, fixed wireless[->95] Internet access, video calls[->96] and mobile TV[->97].
Several telecommunications companies market wireless mobile Internet services as 3G, indicating that the advertised service is provided over a 3G wireless network. Services advertised as 3G are required to meet IMT-2000 technical standards, including standards for reliability and speed (data transfer rates). To meet the IMT-2000 standards, a system is required to provide peak data rates of at least 200 kbit/s[->98] (about 0.2 Mbit/s[->99]). However, many services advertised as 3G provide higher speed than the minimum technical requirements for a 3G service. Recent 3G releases, often denoted 3.5G[->100] and 3.75G[->101], also provide mobile broadband[->102] access of several Mbit/s[->103] to smartphones[->104] and mobile modems[->105] in laptop computers.

3G is the next generation of technology which has revolutionized the telecommunication industry. Apart from increasing the speed of communication, the objective of this technology is to provide various value added services like video calling, live streaming, mobile internet access, IPTV, etc on the mobile phones. These services are possible because the 3G spectrum provides the necessary bandwidth.

Technically speaking 3G is a network protocol which refers to the generations of mobile phones and telecommunication equipments which are compatible with the International Mobile Telecommunications-2000 (IMT-2000) standards stated by International Telecommunication Union (ITU). The basic requirement for compiling to IMT-2000 standards is that the technology should provide peak data rates of atleast 200 kbit/s. It’s worth mentioning that speed isn’t the only criteria for deciding whether the network protocol is 3G or not. 3G isn’t just any high speed network but a protocol which has its own standards defined under IMT-2000 by ITU. 3G Technology is designed for multimedia communication. It provides services like higher data transfer rates. One of its key visions is to provide seamless global roaming, enabling users to move across borders while using the same number and handset. According to ITU it is expected that IMT-2000 will provide higher transmission rates: a minimum speed of 2Mbit/s for stationary or walking users, and 348kbit/s in a moving vehicle. Birth of IMT-2000
The concept of IMT came into existence in the mid-1980s at ITU. It took more than ten years for the approval of standards for the next generation systems. These standards are branded as IMT-2000. Under the technical specifications the spectrum between 400 MHz and 3 GHz was dictated technically suitable for the third generation. IMT-2000 is the result of collaboration of many entities, inside the ITU (ITU-R and ITU-T), and outside the ITU (3GPP, 3GPP2, UWCC and so on). This approval has made possible the full interoperability and interworking of mobile systems. It facilitates five radio interfaces based on three technologies namely FDMA, TDMA and CDMA. The accommodated radio interfaces are : IMT-DS, IMT-MC, IMT-SC, IMT-TC, IMT-FT Contributor Technologies of 3G
The 3G technology is comprised of basically three technologies, but it is not the reason for its nomenclature as 3G. The technologies are: · CDMA2000 - Code Division Multiple Access.
TD-SCDMA - Time-division Synchronous Code-division Multiple Access.
· W-CDMA (UMTS) - Wideband Code Division Multiple Access

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