This article may be too technical for most readers to understand. Please help improve this article to make it understandable to non-experts, without removing the technical details. The talk page may contain suggestions. (December 2011)

In telecommunications, 4G is the fourth generation of cell phone mobile communications standards. It is a successor of the third generation (3G) standards. A 4G system provides mobile ultra-broadband Internet access, for example to laptops with USB wireless modems, to smartphones, and to other mobile devices. Conceivable applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing and 3D television.

Two 4G candidate systems are commercially deployed: The Mobile WiMAX standard (at first in South Korea in 2006), and the first-release Long term evolution (LTE) standard (in Scandinavia since 2009). It has however been debated if these first-release versions should be considered as 4G or not. See technical definition. In the U.S. Sprint Nextel has deployed Mobile WiMAX networks since 2008, and MetroPCS was the first operator to offer LTE service in 2010. USB wireless modems have been available since the start, while WiMAX smartphones have been available since 2010, and LTE smartphones since 2011. Equipment made for different continents are not always compatible, because of different frequency bands. Mobile WiMAX and LTE smartphones are currently (April 2012) not available for the European market.

Technical definition[link]

In March 2008, the International Telecommunications Union-Radio communications sector (ITU-R) specified a set of requirements for 4G standards, named the International Mobile Telecommunications Advanced (IMT-Advanced) specification, setting peak speed requirements for 4G service at 100 megabits per second (Mbit/s) for high mobility communication (such as from trains and cars) and 1 gigabit per second (Gbit/s) for low mobility communication (such as pedestrians and stationary users).^[1]

Since the above mentioned first-release versions of Mobile WiMAX and LTE support much less than 1 Gbit/s peak bit rate, they are not fully IMT-Advanced compliant, but are often branded 4G by service providers. On December 6, 2010, ITU-R recognized that these two technologies, as well as other beyond-3G technologies that do not fulfill the IMT-Advanced requirements, could nevertheless be considered "4G", provided they represent forerunners to IMT-Advanced compliant versions and "a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed".^[2]

Mobile WiMAX Release 2 (also known as WirelessMAN-Advanced or IEEE 802.16m') and LTE Advanced (LTE-A) are IMT-Advanced compliant backwards compatible versions of the above two systems, standardized during the spring 2011,^{[citation needed]} and promising peak bit rates in the order of 1 Gbit/s. Services are expected in 2013.^[3]

As opposed to earlier generations, a 4G system does not support traditional circuit-switched telephony service, but all-internet protocol (IP) based communication such as IP telephony. As seen below, the spread spectrum radio technology used in 3G systems, is abandoned in all 4G candidate systems and replaced by OFDMA multi-carrier transmission and other frequency-domain equalization (FDE) schemes, making it possible to transfer very high bit rates despite extensive multi-path radio propagation (echoes). The peak bit rate is further improved by smart antenna arrays for multiple-input multiple-output (MIMO) communications.

Background[link]

The nomenclature of the generations generally refers to a change in the fundamental nature of the service, non-backwards-compatible transmission technology, higher peak bitrates, new frequency bands, wider channel frequency bandwidth in Hertz, and higher capacity for many simultaneous data transfers (higher system spectral efficiency in bit/second/Hertz/site).

New mobile generations have appeared about every ten years since the first move from 1981 analog (1G) to digital (2G) transmission in 1992. This was followed, in 2001, by 3G multi-media support, spread spectrum transmission and at least 200 kbit/s peak bitrate, in 2011/2012 expected to be followed by "real" 4G, which refers to all-Internet Protocol (IP) packet-switched networks giving mobile ultra-broadband (gigabit speed) access.

While the ITU has adopted recommendations for technologies that would be used for future global communications, they do not actually perform the standardization or development work themselves, instead relying on the work of other standards bodies such as IEEE, The WiMAX Forum and 3GPP.

In mid 1990s, the ITU-R standardization organization released the IMT-2000 requirements as a framework for what standards should be considered 3G systems, requiring 200 kbit/s peak bit rate. In 2008, ITU-R specified the IMT-Advanced (International Mobile Telecommunications Advanced) requirements for 4G systems.

The fastest 3G-based standard in the UMTS family is the HSPA+ standard, which was commercially available in 2009 and offers 28 Mbit/s downstreams (22 Mbit/s upstreams) without MIMO, i.e. only with one antenna, and in 2011 accelerated up to 42 Mbit/s peak bit rate downstreams using either DC-HSPA+ (simultaneous use of two 5 MHz UMTS carrier)^[4] or 2x2 MIMO. In theory 672 Mbit/s is possible, but still not deployed. The fastest 3G-based standard in the CDMA2000 family is the EV-DO Rev. B, which was available in 2010 and offers 15.67 Mbit/s downstreams.^{[citation needed]}

IMT-Advanced Requirements[link]

This article uses 4G to refer to IMT-Advanced (International Mobile Telecommunications Advanced), as defined by ITU-R. An IMT-Advanced cellular system must fulfill the following requirements:^[5]

• Based on an all-IP packet switched network.
• Peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access.
• Dynamically share and use the network resources to support more simultaneous users per cell.
• Scalable channel bandwidth 5–20 MHz, optionally up to 40 MHz.^[6][7]
• Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth).
• System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage.^[6]
• Smooth handovers across heterogeneous networks.
• Ability to offer high quality of service for next generation multimedia support.

In September 2009, the technology proposals were submitted to the International Telecommunication Union (ITU) as 4G candidates.^[8] Basically all proposals are based on two technologies:

• LTE Advanced standardized by the 3GPP
• 802.16m standardized by the IEEE (i.e. WiMAX)

Implementations of Mobile WiMAX and first-release LTE are largely considered a stopgap solution that will offer a considerable boost until WiMAX 2 (based on the 802.16m spec) and LTE Advanced are deployed. The latter standard versions were ratified in spring 2011, but are still far from being implemented.^[5]

The first set of 3GPP requirements on LTE Advanced was approved in June 2008.^[9] LTE Advanced was to be standardized in 2010 as part of Release 10 of the 3GPP specification. LTE Advanced will be based on the existing LTE specification Release 10 and will not be defined as a new specification series. A summary of the technologies that have been studied as the basis for LTE Advanced is included in a technical report.^[10]

First release LTE and Mobile WiMAX implementations are in some sources considered pre-4G or near-4G, as they do not fully comply with the planned requirements of 1 Gbit/s for stationary reception and 100 Mbit/s for mobile.

Confusion has been caused by some mobile carriers who have launched products advertised as 4G but which according to some sources are pre-4G versions, commonly referred to as '3.9G', which do not follow the ITU-R defined principles for 4G standards, but today can be called 4G according to ITU-R. A common argument for branding 3.9G systems as new-generation is that they use different frequency bands from 3G technologies; that they are based on a new radio-interface paradigm; and that the standards are not backwards compatible with 3G, whilst some of the standards are forwards compatible with IMT-2000 compliant versions of the same standards.

System standards[link]

IMT-2000 compliant 4G standards[link]

Recently, ITU-R Working Party 5D approved two industry-developed technologies (LTE Advanced and WirelessMAN-Advanced)^[11] for inclusion in the ITU’s International Mobile Telecommunications Advanced (IMT-Advanced program), which is focused on global communication systems that would be available several years from now.

LTE Advanced[link]

See also: 3GPP Long Term Evolution (LTE) below

LTE Advanced (Long-term-evolution Advanced) is a candidate for IMT-Advanced standard, formally submitted by the 3GPP organization to ITU-T in the fall 2009, and expected to be released in 2012. The target of 3GPP LTE Advanced is to reach and surpass the ITU requirements.^[12] LTE Advanced is essentially an enhancement to LTE. It is not a new technology but rather an improvement on the existing LTE network. This upgrade path makes it more cost effective for vendors to offer LTE and then upgrade to LTE Advanced which is similar to the upgrade from WCDMA to HSPA. LTE and LTE Advanced will also make use of additional spectrum and multiplexing to allow it to achieve higher data speeds. Coordinated Multi-point Transmission will also allow more system capacity to help handle the enhanced data speeds. Release 10 of LTE is expected to achieve the LTE Advanced speeds. Release 8 currently supports up to 300 Mbit/s download speeds which is still short of the IMT-Advanced standards.^[13]

IEEE 802.16m or WirelessMAN-Advanced[link]

The IEEE 802.16m or WirelessMAN-Advanced evolution of 802.16e is under development, with the objective to fulfill the IMT-Advanced criteria of 1 Gbit/s for stationary reception and 100 Mbit/s for mobile reception.^[14]

Forerunner versions[link]

3GPP Long Term Evolution (LTE)[link]

See also: LTE Advanced above

Telia-branded Samsung LTE modem

The pre-4G technology 3GPP Long Term Evolution (LTE) is often branded "4G-LTE", but the first LTE release does not fully comply with the IMT-Advanced requirements. LTE has a theoretical net bit rate capacity of up to 100 Mbit/s in the downlink and 50 Mbit/s in the uplink if a 20 MHz channel is used — and more if multiple-input multiple-output (MIMO), i.e. antenna arrays, are used.

The physical radio interface was at an early stage named High Speed OFDM Packet Access (HSOPA), now named Evolved UMTS Terrestrial Radio Access (E-UTRA). The first LTE USB dongles do not support any other radio interface.

The world's first publicly available LTE service was opened in the two Scandinavian capitals Stockholm (Ericsson and Nokia Siemens Networks systems) and Oslo (a Huawei system) on 14 December 2009, and branded 4G. The user terminals were manufactured by Samsung.^[15] Currently, the three publicly available LTE services in the United States are provided by MetroPCS,^[16] Verizon Wireless,^[17] and AT&T. As of April 2012, US Cellular^[18] also offers 4G LTE. Sprint Nextel has also stated it's considering switching from WiMax to LTE in the near future.^[17]

T-Mobile Hungary launched a public beta test (called friendly user test) on 7 October 2011, and offers commercial 4G LTE service since 1 January 2012.^{[citation needed]}

In South Korea, SK Telecom and LG U+ have enabled access to LTE service since 1 July 2011 for data devices, slated to go nationwide by 2012.^[19]

Mobile WiMAX (IEEE 802.16e)[link]

The Mobile WiMAX (IEEE 802.16e-2005) mobile wireless broadband access (MWBA) standard (also known as WiBro in South Korea) is sometimes branded 4G, and offers peak data rates of 128 Mbit/s downlink and 56 Mbit/s uplink over 20 MHz wide channels^{[citation needed]}.

In June 2006, the world's first commercial mobile WiMAX service was opened by KT in Seoul, South Korea.^[20]

Sprint Nextel has begun using Mobile WiMAX, as of September 29, 2008 branded as a "4G" network even though the current version does not fulfil the IMT Advanced requirements on 4G systems.^[21]

In Russia, Belarus and Nicaragua WiMax broadband internet access is offered by a Russian company Scartel, and is also branded 4G, Yota.

TD-LTE for China Market[link]

Just when Long-Term Evolution (LTE) and WiMax vigorously promoting in the global telecommunications industry, the former (LTE) is also the most powerful 4G mobile communication leading technology, is a meteoric rise, and quickly occupied the Chinese market. Qualcomm and the Yota's TD-LTE is not yet mature, but many domestic and international wireless carriers one after another turn to TD-LTE. IBM data show that 67% of the operators are considering LTE, because this is the main source of their future market. The above news also confirmed this statement of IBM. While only 8% of the operators to consider the use of WiMAX. WiMax can provide the fastest network transmission to its customers on the market, but still not the rival of LTE. TD-LTE is not the first 4G wireless mobile broadband network data standard, it is China's 4G standard that amendmented and published by China's largest telecom operators - China Mobile. After a series of field trials, is expected into the commercial phase in the next two years . Ulf Ewaldsson, Ericsson's vice president said: "the Chinese Ministry of Industry and China Mobile in the fourth quarter of this year will hold a large-scale field test, by then, Ericsson will help the hand." But view from the current development trend, whether this standard advocated by China Mobile will be widely recognized by the international market, is still debatable.

Discontinued candidate systems[link]

UMB (formerly EV-DO Rev. C)[link]

UMB (Ultra Mobile Broadband) was the brand name for a discontinued 4G project within the 3GPP2 standardization group to improve the CDMA2000 mobile phone standard for next generation applications and requirements. In November 2008, Qualcomm, UMB's lead sponsor, announced it was ending development of the technology, favouring LTE instead.^[22] The objective was to achieve data speeds over 275 Mbit/s downstream and over 75 Mbit/s upstream.

Flash-OFDM[link]

At an early stage the Flash-OFDM system was expected to be further developed into a 4G standard.

iBurst and MBWA (IEEE 802.20) systems[link]

The iBurst system (or HC-SDMA, High Capacity Spatial Division Multiple Access) was at an early stage considered as a 4G predecessor. It was later further developed into the Mobile Broadband Wireless Access (MBWA) system, also known as IEEE 802.20.

Data rate comparison[link]

The following table shows a comparison of 4G candidate systems as well as other competing technologies.

Notes: All speeds are theoretical maximums and will vary by a number of factors, including the use of external antennae, distance from the tower and the ground speed (e.g. communications on a train may be poorer than when standing still). Usually the bandwidth is shared between several terminals. The performance of each technology is determined by a number of constraints, including the spectral efficiency of the technology, the cell sizes used, and the amount of spectrum available. For more information, see Comparison of wireless data standards.

For more comparison tables, see bit rate progress trends, comparison of mobile phone standards, spectral efficiency comparison table and OFDM system comparison table.

Principal technologies in all candidate systems[link]

Key features[link]

The following key features can be observed in all suggested 4G technologies:

• Physical layer transmission techniques are as follows:^[25]
  • MIMO: To attain ultra high spectral efficiency by means of spatial processing including multi-antenna and multi-user MIMO
  • Frequency-domain-equalization, for example multi-carrier modulation (OFDM) in the downlink or single-carrier frequency-domain-equalization (SC-FDE) in the uplink: To exploit the frequency selective channel property without complex equalization
  • Frequency-domain statistical multiplexing, for example (OFDMA) or (single-carrier FDMA) (SC-FDMA, a.k.a. linearly precoded OFDMA, LP-OFDMA) in the uplink: Variable bit rate by assigning different sub-channels to different users based on the channel conditions
  • Turbo principle error-correcting codes: To minimize the required SNR at the reception side
• Channel-dependent scheduling: To use the time-varying channel
• Link adaptation: Adaptive modulation and error-correcting codes
• Mobile-IP utilized for mobility
• IP-based femtocells (home nodes connected to fixed Internet broadband infrastructure)

As opposed to earlier generations, 4G systems does not support circuit switched telephony. Most^[which?] 4G standards lack soft-handover support, also known as cooperative relaying.

Multiplexing and Access schemes[link]

This section contains information which may be of unclear or questionable importance or relevance to the article's subject matter. Please help improve this article by clarifying or removing superfluous information. (May 2010)

The Migration to 4G standards incorporates elements of many early technologies and often you will read about solutions that use Code (a cypher), Frequency or Time as the basis of multiplexing the spectrum more efficiently. While Spectrum is considered finite, Cooper's Law has shown that we have developed more efficient ways of using spectrum just as the Moore's law has show our ability to increase processing.

As the wireless standards evolved, the access techniques used also exhibited increase in efficiency, capacity and scalability. The first generation wireless standards used TDMA and FDMA. In the wireless channels, TDMA proved to be less efficient in handling the high data rate channels as it requires large guard periods to alleviate the multipath impact. Similarly, FDMA consumed more bandwidth for guard to avoid inter carrier interference. So in second generation systems, one set of standard used the combination of FDMA and TDMA and the other set introduced an access scheme called CDMA. Usage of CDMA increased the system capacity, but as a theoretical drawback placed a soft limit on it rather than the hard limit (i.e. a CDMA network setup does not inherently reject new clients when it approaches its limits, resulting in a denial of service to all clients when the network overloads; though this outcome is avoided in practical implementations by admission control of circuit switched or fixed bitrate communication services). Data rate is also increased as this access scheme (providing the network is not reaching its capacity) is efficient enough to handle the multipath channel. This enabled the third generation systems, such as IS-2000, UMTS, HSXPA, 1xEV-DO, TD-CDMA and TD-SCDMA, to use CDMA as the access scheme. However, the issue with CDMA is that it suffers from poor spectral flexibility and computationally intensive time-domain equalization (high number of multiplications per second) for wideband channels.

Recently, new access schemes like Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Interleaved FDMA and Multi-carrier CDMA (MC-CDMA) are gaining more importance for the next generation systems. These are based on efficient FFT algorithms and frequency domain equalization, resulting in a lower number of multiplications per second. They also make it possible to control the bandwidth and form the spectrum in a flexible way. However, they require advanced dynamic channel allocation and traffic adaptive scheduling.

WiMax is using OFDMA in the downlink and in the uplink. For the next generation UMTS, OFDMA is used for the downlink. By contrast, Singel-carrier FDE is used for the uplink since OFDMA contributes more to the PAPR related issues and results in nonlinear operation of amplifiers. IFDMA provides less power fluctuation and thus require energy-inefficient linear amplifiers. Similarly, MC-CDMA is in the proposal for the IEEE 802.20 standard. These access schemes offer the same efficiencies as older technologies like CDMA. Apart from this, scalability and higher data rates can be achieved.

The other important advantage of the above mentioned access techniques is that they require less complexity for equalization at the receiver. This is an added advantage especially in the MIMO environments since the spatial multiplexing transmission of MIMO systems inherently requires high complexity equalization at the receiver.

In addition to improvements in these multiplexing systems, improved modulation techniques are being used. Whereas earlier standards largely used Phase-shift keying, more efficient systems such as 64QAM are being proposed for use with the 3GPP Long Term Evolution standards.

IPv6 support[link]

Unlike 3G, which is based on two parallel infrastructures consisting of circuit switched and packet switched network nodes respectively, 4G will be based on packet switching only. This will require low-latency data transmission.

By the time that 4G was deployed, the process of IPv4 address exhaustion was expected to be in its final stages. Therefore, in the context of 4G, IPv6 support is essential to support a large number of wireless-enabled devices. By increasing the number of IP addresses, IPv6 removes the need for network address translation (NAT), a method of sharing a limited number of addresses among a larger group of devices, although NAT will still be required to communicate with devices that are on existing IPv4 networks.

As of June 2009^[update], Verizon has posted specifications that require any 4G devices on its network to support IPv6.^[26]

Advanced antenna systems[link]

The performance of radio communications depends on an antenna system, termed smart or intelligent antenna. Recently, multiple antenna technologies are emerging to achieve the goal of 4G systems such as high rate, high reliability, and long range communications. In the early 1990s, to cater for the growing data rate needs of data communication, many transmission schemes were proposed. One technology, spatial multiplexing, gained importance for its bandwidth conservation and power efficiency. Spatial multiplexing involves deploying multiple antennas at the transmitter and at the receiver. Independent streams can then be transmitted simultaneously from all the antennas. This technology, called MIMO (as a branch of intelligent antenna), multiplies the base data rate by (the smaller of) the number of transmit antennas or the number of receive antennas. Apart from this, the reliability in transmitting high speed data in the fading channel can be improved by using more antennas at the transmitter or at the receiver. This is called transmit or receive diversity. Both transmit/receive diversity and transmit spatial multiplexing are categorized into the space-time coding techniques, which does not necessarily require the channel knowledge at the transmitter. The other category is closed-loop multiple antenna technologies, which require channel knowledge at the transmitter.

Open-wireless Architecture and Software-defined radio (SDR)[link]

One of the key technologies for 4G and beyond is called Open Wireless Architecture (OWA), supporting multiple wireless air interfaces in an open architecture platform.

SDR is one form of open wireless architecture (OWA). Since 4G is a collection of wireless standards, the final form of a 4G device will constitute various standards. This can be efficiently realized using SDR technology, which is categorized to the area of the radio convergence.

History of 4G and pre-4G technologies[link]

The 4G system was originally envisioned by the Defense Advanced Research Projects Agency (DARPA).^{[citation needed]} 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.^[27] 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 is provided, while 2.5G and 3G systems require both packet-switched and circuit-switched network nodes, 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 designated as IMT-Advanced—was laid out.
• In 2005, OFDMA transmission technology is chosen as candidate for the HSOPA downlink, later renamed 3GPP Long Term Evolution (LTE) air interface E-UTRA.
• In November 2005, KT demonstrated mobile WiMAX service in Busan, South Korea.^[28]
• In April 2006, KT started the world's first commercial mobile WiMAX service in Seoul, South Korea.^[29]
• In mid-2006, Sprint Nextel announced that it would invest about US$5 billion in a WiMAX technology buildout over the next few years^[30] ($5.76 billion in real terms^[31]). Since that time Sprint has faced many setbacks, that have resulted in steep quarterly losses. On May 7, 2008, Sprint, Imagine, Google, Intel, Comcast, Bright House, and Time Warner announced a pooling of an average of 120 MHz of spectrum; Sprint merged its Xohm WiMAX division with Clearwire to form a company which will take the name "Clear".
• In February 2007, the Japanese company NTT DoCoMo tested a 4G communication system prototype with 4x4 MIMO called VSF-OFCDM at 100 Mbit/s while moving, and 1 Gbit/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 12x12 MIMO using a 100 MHz frequency bandwidth while moving at 10 km/h,^[32] 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.^[33]
• In January 2008, a U.S. Federal Communications Commission (FCC) spectrum auction 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.^[34] Both of these companies have stated their intention of supporting LTE.
• In January 2008, EU commissioner Viviane Reding suggested re-allocation of 500–800 MHz spectrum for wireless communication, including WiMAX.^[35]
• On 15 February 2008 - Skyworks Solutions released a front-end module for e-UTRAN.^[36][37][38]
• In 2008, ITU-R established the detailed performance requirements of IMT-Advanced, by issuing a Circular Letter calling for candidate Radio Access Technologies (RATs) for IMT-Advanced.^[39]
• 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.^[40]
• On 12 November 2008, HTC announced the first WiMAX-enabled mobile phone, the Max 4G^[41]
• In December 2008, San Miguel Corporation, southeast Asia's largest food and beverage conglomerate, has signed a memorandum of understanding with Qatar Telecom QSC (Qtel) to build wireless broadband and mobile communications projects in the Philippines. The joint-venture formed wi-tribe Philippines, which offers 4G in the country.^[42] Around the same time Globe Telecom rolled out the first WiMAX service in the Philippines.
• On 3 March 2009, Lithuania's LRTC announcing the first operational "4G" mobile WiMAX network in Baltic states.^[43]
• 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).^[44]
• On 14 December 2009, the first commercial LTE deployment was in the Scandinavian capitals Stockholm and Oslo by the Swedish-Finnish network operator TeliaSonera and its Norwegian brandname NetCom (Norway). TeliaSonera branded the network "4G". The modem devices on offer were manufactured by Samsung (dongle GT-B3710), and the network infrastructure created by Huawei (in Oslo) and Ericsson (in Stockholm). TeliaSonera plans to roll out nationwide LTE across Sweden, Norway and Finland.^[45][46] TeliaSonera used spectral bandwidth of 10 MHz, and single-in-single-out, which should provide physical layer net bitrates of up to 50 Mbit/s downlink and 25 Mbit/s in the uplink. Introductory tests showed a TCP throughput of 42.8 Mbit/s downlink and 5.3 Mbit/s uplink in Stockholm.^[47]
• On 25 February 2010, Estonia's EMT opened LTE "4G" network working in test regime.^[48]
• On 4 June 2010, Sprint Nextel released the first WiMAX smartphone in the US, the HTC Evo 4G.^[49]
• In July 2010, Uzbekistan's MTS deployed LTE in Tashkent.^[50]
• On 25 August 2010, Latvia's LMT opened LTE "4G" network working in test regime 50% of territory.
• On 6 December 2010, at the ITU World Radiocommunication Seminar 2010, the ITU stated that LTE, WiMax and similar "evolved 3G technologies" could be considered "4G".^[2]
• On 12 December 2010, VivaCell-MTS launches in Armenia 4G/LTE commercial test network with a live demo conducted in Yerevan.^[51]
• On 28 April 2011, Lithuania's Omnitel opened LTE "4G" network working in 5 biggest cities.^[52]
• In September 2011, All three Saudi telecom companies STC, Mobily and Zain announced that they will offer 4G LTE for high speed USB sticks for mobile computers, with further development for telephones by 2013.^[53]
• In 2011, Argentina´s Claro launch 4G HSPA+ network in the country.
• In 2011, Thailand's Truemove-H launch 4G HSPA+ network with nation-wide availability.
• On February 10, 2011, the Samsung Galaxy Indulge offered by MetroPCS is the first commercially available LTE smartphone^[54][55]
• On March 17, 2011, HTC ThunderBolt offered by Verizon in the U.S. was the second LTE smartphone to be sold commercially.^[56][57]
• On 31 January 2012, Thailand's AIS and its subsidiaries DPC under co-operative with CAT Telecom for 1800 MHz frequency band and TOT for 2300 MHz frequency band launch the first field trial LTE in Thailand by authorization from NBTC^[58]
• In February 2012, Ericsson demonstrated mobile-TV over LTE, utilizing the new eMBMS service (enhanced Multimedia Broadcast Multicast Service).^[59]
• On 10 April 2012, Bharti Airtel launched 4G [LTE] in Kolkata, first in India which resulted India to be one of the first countries in the world to deploy the cutting edge technology commercially.^[60]
• On 20 May 2012, Azerbaijan's biggest mobile operator Azercell launched 4G [LTE].^[61]

Deployment plans[link]

This section of the article is too long to read comfortably, and needs subsections. Please format the article according to the guidelines laid out in the Manual of Style. (May 2012)

In May 2005, Digiweb, an Irish fixed and wireless broadband company, announced that they had received a mobile communications license from the Irish telecoms regulator ComReg. This service will be issued the mobile code 088 in Ireland and will be used for the provision of 4G mobile communications.^[62][63] Digiweb launched a mobile broadband network using FLASH-OFDM technology at 872 MHz.

On September 20, 2007, Verizon Wireless announced plans for a joint effort with the Vodafone Group to transition its networks to the 4G standard LTE. On December 9, 2008, Verizon Wireless announced their intentions to build and begin to roll out an LTE network by the end of 2009. Since then, Verizon Wireless has said that they will start their rollout by the end of 2010.

On July 7, 2008, South Korea announced plans to spend 60 billion won, or US$58,000,000, on developing 4G and even 5G technologies, with the goal of having the highest mobile phone market share by 2012, and the hope of an international standard.^[64]

Telus and Bell Canada, the major Canadian cdmaOne and EV-DO carriers, have announced that they will be cooperating towards building a fourth generation (4G) LTE wireless broadband network in Canada. As a transitional measure, they are implementing 3G UMTS that went live in November 2009.^[65]

Sprint Nextel offers a 3G/4G connection plan, currently available in select cities in the United States.^[44] It delivers rates up to 10 Mbit/s. Sprint has announced that they will launch a LTE network in early 2012.^[66]

In the United Kingdom and in Ireland, O₂ UK and O₂ Ireland (both subsidiaries of Telefónica Europe) are to use Slough as a guinea pig in testing the 4G network and has called upon Huawei to install LTE technology in six masts across the town to allow people to talk to each other via HD video conferencing and play PlayStation games while on the move.^[67] On February 29, 2012, the first commercial 4G LTE service in the UK launched in Borough of Southwark, London.^[68] Ofcom is in the process of auctioning off the UK-wide 4G spectrum. This will use the airspace made available following the country's analogue television signal switch off.^[69]

Verizon Wireless has announced that it plans to augment its CDMA2000-based EV-DO 3G network in the United States with LTE, and is supposed to complete a rollout of 175 cities by the end of 2011, two thirds of the US population by mid-2012, and cover the existing 3G network by the end of 2013.^[70] AT&T, along with Verizon Wireless, has chosen to migrate toward LTE from 2G/GSM and 3G/HSPA by 2011.^[71]

Sprint Nextel has deployed WiMAX technology which it has labeled 4G as of October 2008. It is currently deploying to additional markets and is the first US carrier to offer a WiMAX phone.^[72]

The U.S. FCC is exploring the possibility of deployment and operation of a nationwide 4G public safety network which would allow first responders to seamlessly communicate between agencies and across geographies, regardless of devices. In June 2010 the FCC released a comprehensive white paper which indicates that the 10 MHz of dedicated spectrum currently allocated from the 1700 MHz spectrum for public safety will provide adequate capacity and performance necessary for normal communications as well as serious emergency situations.^[73]

TeliaSonera started deploying LTE (branded "4G") in Stockholm and Oslo November 2009 (as seen above), and in several Swedish, Norwegian, and Finnish cities during 2010. In June 2010, Swedish television companies used 4G to broadcast live television from the Swedish Crown Princess' Royal Wedding.^[74]

Safaricom, a telecommunication company in East& Central Africa, began its setup of a 4G network in October 2010 after the now retired& Kenya Tourist Board Chairman, Michael Joseph, regarded their 3G network as a white elephant i.e. it failed to perform to expectations. Huawei was given the contract the network is set to go fully commercial by the end of Q1 of 2011

Telstra announced on 15 February 2011, that it intends to upgrade its current Next G network to 4G with Long Term Evolution (LTE) technology in the central business districts of all Australian capital cities and selected regional centers by the end of 2011.^[75][when?]

Sri Lanka Telecom Mobitel and Dialog Axiata announced that first time in South Asia Sri Lanka have successfully tested and demonstrated 4G technology on 6 May 2011(Sri Lanka Telecom Mobitel) and 7 May 2011(Dialog Axiata) and began the setup of their 4G Networks in Sri Lanka.^[76][77]

Mobitel was able to reach 96Mbit/s of speed while Dialog Axiata reached 128Mbit/s on their demonstration.

In mid September 2011, [5] Mobily of Saudi Arabia, announced their 4G LTE networks to be ready after months of testing and evaluations.

In December 2011, UAE's Etisalat announced commercial launch of 4G LTE services covering over 70% of country's urban areas.^{[citation needed]} As of May, 2012 only few areas have been covered.^{[citation needed]}

In India on 10 April 2012, India's telecom company Bharti Airtel has launched India's first 4g services in Kolkata using TD-LTE technology.^[78] It's only 14 months back before the official launching in Kolkata when a group consisting of China Mobile, Bharti Airtel and SoftBank Mobile came together, called GTI (Global TDLTE Initiative) in Barcelona and they signed the commitment towards TD-LTE (Time-Division Long-Term Evolution) standards for the Asian region.

On 27 April 2012, Brazil’s telecoms regulator Agencia Nacional de Telecomunicacoes (Anatel) announced that the 6 host cities for the 2013 Confederations Cup to be held there will be the first to have their networks upgraded to 4G.^[79]

Beyond 4G research[link]

A major issue in 4G systems is to make the high bit rates available in a larger portion of the cell, especially to users in an exposed position in between several base stations. In current research, this issue is addressed by macro-diversity techniques, also known as group cooperative relay, and also by Beam-Division Multiple Access (BDMA).^[80]

Pervasive networks are an amorphous and at present entirely hypothetical concept where the user can be simultaneously connected to several wireless access technologies and can seamlessly move between them (See vertical handoff, IEEE 802.21). These access technologies can be Wi-Fi, UMTS, EDGE, or any other future access technology. Included in this concept is also smart-radio (also known as cognitive radio) technology to efficiently manage spectrum use and transmission power as well as the use of mesh routing protocols to create a pervasive network.

See also[link]

• Mobile radio telephone (also known as "0G")
• 1G
• 2G
• 3G
• 5G

References[link]