LTE (Telecommunication) from Wikipedia, the Free Encyclopedia

66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa LTE (telecommunication) From Wikipedia, the free encyclopedia

LTLTEE, an ininitialismitialism ooff long-term evolution, marketed as 4G LTE, is a standard for wireless communication of high-spehigh-speeded data foforr mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA

network technologies,improvements. increasing[1][2] The thestandard capacity is developedand speed byusing the a 3GPP different (3rd radio Generat interfaceion Partnership together wit Project)h core and is specified in its Release 8 document series, with minor enhancements described in Release 9.

The world's first pubpublliiclclyy avaiavailablelable LTE ser ser vicevice was launchedlaunched by by TTeleliiaSonaSoneera inira n Oslo and StocStockholmkholm on DecemDecemberber 14 2009.[3][3] LTE is the natural upgrade path for carriers with both GSM/UMTSGSM/UMTS networks networks anandd CDMA networks such as Verizon WirelWireless,ess, who laulaunchednched the fifirstrst large-sclarge-scaalele LTE networ networ kk in North America in 2010,[4][5] and au by KDDI in JapaJapann havehave announced ththeyey will migramigratete to LTE. LTE is, Adoption of LTE technology as of May 8, 2012. therefore, anticipated toto be becomecome the first truly global mobile phone standard, although the differedifferentnt LTE CountrieCountriess with commerccommercialial LTE service frequencies and bands used in different countries will mean that only multi-band phones will be able to use CountrieCountriess with commerccommercialial LTE network LTE in all countries where it is supported. deployment on-going or planned CountrieCountriess withwith LTE trial syssystemstems (pre- AlthAlthoughough marketed as a 4G wireless service, LTE (as spespecifiedcified in the 3GPP Release 8and 9 document serieseries)s) doedoess not satisfy the technicalthe technical reqrequirementsuirements the 3GPP consortium has adoadoptedpted for its nnewew standard commitment) generation, and whicwhichhwerewere originally set forth by the ITU-R organization in its IMT-Advanced specification. However, due to marketing pressures and the significsignificaantnt adadvavanncementscements that WIMWIMAX,AX, HSPA+ and LTE bring to the origioriginalnal 3G technologies,technologies, ITU later decided that LTE together with the aforementioned technologies can be called 4G technoltechnologies.ogies.[6][6] The LTE Advanced standard foformallyrmally satisfies the IITU-R TU-R requirements to be consconsiidder er eded IMT-Advanced.[7][7] An Andd to to difffferentiatedi erentiate LTE-Advanced aandnd WiWiMAX-AdvancedMAX-Advanced from current 4G techntechnologies,ologies, ITU has defined them as "True 4G".[8][9]

Contents

1 Overview 2 Features

3 Voice calls 3.1 Enhanced voice quality 4 Frequency bands

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66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa 5 Patents 6 See also 7 References 8 Further reading 9 External links 9.1 White papers and other technical information

Overview

See alsalso:o: LTE timeline and List of LTE netwnetworksorks

LTE is a standard for wireless data communications technology and an evolution of the GSM/UMTS standards. The goal of LTE was to increase the capacity and speed of wireless data networks using new DSP (digital signal processing) techniques and modulations that were developed around the turn of the millennium. A further goal was the redesign and simplification of the network architecture to an IP-based system with significantly reduced transfer latency compared to the 3G ararchichitecture.tecture. The LTE wiwirelessreless interfinterfaceace is inincompatiblcompatiblee with 2G and 33GG networks, so that it mumustst be operatedoperated on a separate wireless spectrum.

LTE was fifirstrst pproposeroposedd by NNTTTT DoCoMo of Japan in 2004, and studies on the new sstandardtandard oofffficiiciallallyy commcommencedenced in 2005.[10][10] In May 2007, the LTE/SAE Trial Initiative (LSTI) alliance was founded as a global collaboration between vendors and operators with the goal of verifying and promoting the new standard in order to ensure the global introduction of the technology as quickly as possible.[11][12] The LTE standard was finalized in December 2008, and the

TeliTelia-brandeda-branded Samsung LTE modem

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66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa first publicly available LTE service was launched by TeliaSonera in Oslo and Stockholm on December 14, 2009 as a data connection with a USB modem. The LTE services were launched by major North American carriers as well, with the Samsung SCH-r900 being the world’s first LTE Mobile phone starting on September 21, 2010[13][14] and Samsung Galaxy Indulge being the world’s first LTE smartphone starting on February 10, 2011 [15][16] both offered by MetroPCS and HTC ThunderBolt offered by Verizon starting on March 17 being the second LTE smartphone to be sold commercially.[17][18] In Canada, Rogers Wireless was the first to launch LTE network on July 7, 2011 offering the Sierra Wireless AirCard® 313U USB mobile broadband modem, known as the "LTE Rocket™ stick" then followed closely by mobile devices from both HTC and Samsung.[19][19] Initially, CDMA operators planned to upgrade to rival standards called UMB and WiMAX, but all the major CDMA operators (such as Verizon, Sprint and MetroPCS in the United States, Bell and Telus in Canada, au by KDDI in Japan, SK Telecom in South Korea and China Telecom/China Unicom in China) have announced that they intend to migrate to LTE after all. The evolution of LTE is LTE Advanced, which was standardized in March 2011.[20][20] Services are expected to commence in 2013.[21][21]

The LTE specification provides downlink peak rates of 300 Mbit/s, uplink peak rates of 75 Mbit/s and QoS provisions perm permiittittingng a transfsfertran latenler atencycy of llessess ththanan 5 mms is in thetn he radiradioo accesaccess netwns etwork.ork. LLTETE hahas ths thee abiabilliityty to mmananagage fe fast-mast-movoviingng mobiles and supports multi-cast and broadcast streams. LTE supports scalable carrier bandwidths, from 1.4 MHz to 20 MHz and supports both frequency division duplexing (FDD) and time-division duplexing (TDD). The IP-based HHTCTC ThunderBolt, the sec ondond network architecture, called the Evolved Packet Core (EPC) and designed to replace the GPRS Core Network, commercially available LTE supports seamless handovers for both voice and data to cell towers with older network technology such as GSM, UMTS smartphone and CDMA2000.[22][22] The simpler architecture results in lower operating costs (for example, each E-UTRAN cell will support up to four times the data and voice capacity supported by HSPA[23][23]).).

Features

See also: E-UTRA

Much of the LTE standard addresses the upgrading of 3G UMTS to what will eventually be 4G mobile communications technology. A large amount of the work is aimed at simplifying the architecture of the system, as it transits from the existing UMTS circuit + packet switching combined network, to an all-IP flat architecture system. E-UTRA is the air interface of LTE. Its main features are:

Peak download rates up to 299.6 Mbit/s and upload rates up to 75.4 Mbit/s depending on the user equipment category (with 4x4 antennas using 20 MHz o spectrum). Five different terminal classes have been defined from a voice centric class up to a high end terminal that supports the peak data rates. All terminals will be able to process 20 MHz bandwidth. Low data transfer latencies (sub-5 ms latency for small IP packets in optimal conditions), lower latencies for handover and connection setup time than with

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66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa prev previiousous radioradio accesaccesss techtechnonollogogiies.es. Improved support for mobility, exemplified by support for terminals moving at up to 350 km/h (220 mph) or 500 km/h (310 mph) depending on the frequency band.[24][24] OFDMA for the downlink, SC-FDMA for the uplink to conserve power Support for both FDD and TDD communication systems as well as half-duplex FDD with the same radio access technology Support for all frequency bands currently used by IMT systems by ITU-R. Increased spectrum flexibility: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz wide cells are standardized. (W-CDMA requires 5 MHz slices, leading to some problems with roll-outs of the technology in countries where 5 MHz is a commonly allocated amount of spectrum, and is frequently already in use with legacy standards such as 2G GSM and cdmaOne.) Support for cell sizes from tens of metres radius (femto and picocells) up to 100 km (62 miles) radius macrocells. In the lower frequency bands to be used in rural areas, 5 km (3.1 miles) is the optimal cell size, 30 km (19 miles) having reasonable performance, and up to 100 km cell sizes supported with acceptable perf performormanance.ce. In cicityty anand urbanud rban areasareas, hi, highgher frequfer requenencycy banbandsds (such(such aass 2.6 GGHzHz iin EU)En U) aarere uusedsed to susupportpport hihighgh speed mmobiobillee broabroadbandband.d. In ththiiss case,case, celllcel sizes may be 1 km (0.62 miles) or even less. Supports at least 200 active data clients in every 5 MHz cell.[25][25] Simplified architecture: The network side of E-UTRAN is composed only of eNode Bs Support for inter-operation and co-existence with legacy standards (e.g. GSM/EDGE, UMTS and CDMA2000). Users can start a call or transfer of data in an area using an LTE standard, and, should coverage be unavailable, continue the operation without any action on their part using GSM/GPRS or W- CDMA-based UMTS or even 3GPP2 networks such as cdmaOne or CDMA2000) Packet switched radio interface. Support for MBSFN (Mul(Multicast-Broadticast-Broadcastcast SingSinglele Frequency NeNetwork).twork). ThiThiss feature can ddelieliverver services such as Mobile TV usingusing ththee LTE infinfrastructure,rastructure, and is a competitor for DVB-H-based TV broadcast.

Voice calls The LTE standard only supports packet switching with its all-IP network. Voice calls in GSM, UMTS and CDMA2000 are circuit switched, so with the adoption of LTE, carriers will have to re-engineer their voice call network. [26][26] Three different approaches sprang up:

VoLTE (Voice Over LTE): This approach is based on the IP Multimedia Subsystem (IMS) network, with specific profiles for control and media planes of voice service on LTE defined by GSMA in PRD IR.92. This approach results in the voice service (control and media planes) being delivered as data flows within the LTE data bearer. This means that there is no dependency on (or ultimately, requirement for) the legacy Circuit Switch voice network to be

maintained. CSCSFBFB (C(Circuiircuit St Switchwitcheded Fallback): In thithiss apapproach,proach, LTE just provides data services, and when a voivoicece ccall iall iss to be ininitiitiatedated or received,received, it wilwilll falfalll back toto

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66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa the CS domain. When using this solution, operators just need to upgrade the MSC instead of deploying the IMS, and therefore, can provide services quickly. However, the disadvantage is longer call setup delay.

SVLTE (Simultaneous Voice and LTE): In this approach, the handset works simultaneously in the LTE and CS modes, with the LTE mode providing data services and the CS mode providing the voice service. This is a solution solely based on the handset, whiwhichch does not have special requiremrequirementsents on the network and doedoess not require the deployment of IMS either. The disadvantage of this solution is that LTE CSFB to GSM/UGSM/UMTSMTS networknetwork interconnects the phone can become expensive with high power consumption.

One adadditiditionalonal approacapproachh whiwhichch is not iniinitiatedtiated by opoperatorserators is the usage of Over-Over-the-topthe-top content services, usinusingg applicationsapplications lilikeke SSkypekype and GoogleGoogle Talk to provide LTE voice service. However, now and in the foreseeable future, the voice call service is, and will still be, the main revenue source for the mobile operators. So handing the LTE voice service over completely to the OTT actors is thus something which is not expected to receive much support in the telecom industry. [27][27]

Most major backers of LTE preferred and promoted VoLTE from the beginning. The lack of software support in initial LTE devices as well as core network devices however led to a number of carriers promoting VoLGA (Voice over LTE Generic Access) as an interim solution. [28][28] The idea was to use the same pri princnciiplpleses as GGANAN (G(Geneneriericc AccAccessess NetwNetwork,ork, alalsoso knknownown as UMAUMA or UUnlnliicencensedsed MobiMobillee AccAccess),ess), wwhihichch defdefiinneses thethe protprotocolocols ths throuroughgh whwhiichch a mobiobillem he hanandsetdset can perform voice calls over a customer's private Internet connection, usually over wireless LAN. VoLGA however never gained much support, because VoLTE (IMS) promises much more flexible services, albeit at the cost of having to upgrade the entire voice call infrastructure. VoLTE will also require Single Radio Voice Call Continuity (SRVCC) in order to be able to smoothly perform a handover to a 3G network in case of poor LTE signal quality. [29][29]

While the industry has seemingly standardized on VoLTE for the future, the demand for voice calls today has led LTE carriers to introduce CSFB as a stopgap measure. When placing or receiving a voice call, LTE handsets will fall back to old 2G or 3G networks for the duration of the call.

Enhanced voice qualitytyquali

To ensure compatibility, 3GPP demands at least AMR-NB codec (narrow band), but the recommended speech codec for VoLTE is Adaptive Multi-Rate Wideband, also known as HD Voice. This codec is mandated in 3GPP networks that support 16 kHz sampling.[30][30]

Fraunhofer IIS has proposed and demonstrated Full-H Full-HDD Voice, an implementation of the AAC-ELD (Advanced Audio Coding – Enhanced Low Delay) codec for LTE handsets.[31][31] Where previoupreviouss cecellll phphoneone voice codecodecscs oonlnlyy supported frequenfrequenciescies up to 3.5 kHz and upcomingupcoming wiwidebanddeband audio services branded asas HD Voice up to 7 kHz, Full-HD Voice supports the entire bandwidth range from 20 Hz to 20 kHz. For end-to-end Full-HD Voice calls to succeed however, both the caller and recipient's handsets as well as networks have to support the feature.[32][32]

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66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa Frequency bands

See also: E-UTRA#Frequency bands and channel bandwidths

The LTE standard cocoversvers a range of manmanyy difdifferentferent bands, eeachach of which iiss dedesigsignatednated by bbothoth a frequencyfrequency and a band number.number. In NorNorthth AmAmerica,erica, 7700,00, 800, 1900 and 1700/2100 MHz (AWS) are used (bands 4, 12, 13, 17, 25); 2500 MHz in South America; 800, 900, 1800, 2600 MHz in Europe(bands 3, 7, 20); 1800 and 2600 MHz in Asia (bands 1, 3, 5, 7, 8, 11, 13, 40); and 1800 MHz in Australia and New Zealand (bands 3, 40). [33][34][35][36][37][38] As a result, ph phonones fes fromrom ononee coucountntryry mmayay nonott worwork inik n ototheherr coucountntriries.es. UsUsersers wwiillll neneeded a mmulultiti-band-band ccapablapablee phphonone fe foror roammiingroa ng iintnternernatiationonalallly.y.

Patents

According to the European TelecommTelecommununicatiicationsons StaStandardsndards Institute's (ETSI) inintelltellectualectual properpropertyty rights (IPR) database,database, about 50 companiescompanies have declared,declared, as of f o March 202012,12, holholdindingg essential patents cocoveriveringng the LTE standard.[39][39] The ETSI has made no investigation on the correctness of the declarations however,[39][39] so so that "any analysis of essential LTE patents should take into account more than ETSI declarations."[40][40]

See also

Comparison of wireless data standards eMBMS – Multicast Broadcast Multimedia Services (MBMS) enhanced for LTE E-UTRA – the radio access network used in LTE Flat IP – flat IP architectures in mobile networks LTE Advanced – the successor to LTE System architecture evolution – the re-architecturing of core networks in LTE TD-LTE (LTE TDD) – an alternative LTE standard developed by China UMB – a proposed competitor to LTE, never commercialized WiMAX – a competitor to LTE HSPA+ – an enhancement of the 3GPP HSPA standard Zadoff–Chu sequence Next Next-gen-generateratiionon nnetwetwork ork

References

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6/2/13 LTE (telecommunication) - Wikipedia, the free encyclopedia

1.1. ^^ "An Introduction to LTE" (http:(http://sites.google.com/site/lte//sites.google.com/site/lteencyclopediaencyclopedia/home)./home). 3GPP LTE Encyclopedia. lopedia. Retrieved December 3, 2010. 2.2. ^^ "Long Term Evolution (LTE): A Technical Overview" (http://www.motorola.com/staticfiles/Business/Solutions/Industry%20Solutions/Service%20Providers/Wireless%20Operators/LTE/_Document/Static%20Files/6834_ MotDoc_New.pdf). Motorola. Retrieved July 3, 2010. 3.3. ^^ TeliaSonera first in the world with 4G services (http://www.teliasonera.com/en/media/press-releases/2009/12/teliasonera-first-in-the-world-with-4g-services/) 4.4. ^^ Verizon Wireless rolled out their LTE network in 38 major markets on December 5, 2010, Happy 1st Anniversary, Verizon Wireless 4G LTE! (http://news.verizonwireless.com/news/2011/12/pr2011-12-05a.html) 5.5. ^^ "Ve "Verizonrizon 4G LTE speedspeed test using Droid BionicBionic (video)" (http://www .smartkeitai.com .smartkeitai.com/veriz/verizon-4g-lte-speed-test-motorola-droid-bionion-4g-lte-speed-test-motorola-droid-bionic-video/).c-video/). September 20, 2011. Retrieved February 4, 2012. 6.6. ^^ "Newsroom • Press Release" (http://www.itu.int/net/pressoffice/press_releases/2010/48.aspx). Itu.int. Retrieved 2012-10-28. 7.7. ^^ "ITU-R Confers IMT-Advanced (4G) Status to 3GPP LTE" (http://www.3gpp.org/ITU-R-Confers-IMT-Advanced-4G) (Press release). 3GPP. 20 October 2010. Retrieved 18 May 2012. 8.8. ^^ pressinfo (2009-10-21). "Press Release: IMT-Advanced (4G) Mobile wireless broadband on the anvil" (http://www.itu.int/newsroom/press_releases/2009/48.html). Itu.int. Retrieved 2012-10-28. 9.9. ^^ "Newsroom • Press Release" (http://www.itu.int/net/pressoffice/press_releases/2012/02.aspx). Itu.int. Retrieved 2012-10-28. 10.10. ^^ "Work Plan 3GPP (Release 8)" (http://www.(http://www.3gpp.org/ftp/I3gpp.org/ftp/Information/WORnformation/WORK_PLK_PLANAN/Description_Re/Description_Relealeases/Rel-08_description_2012012ses/Rel-08_description_20120124.zip).4.zip). 16 JanJanuaryuary 2012. RetriRetrievedeved 1 March 2012. 11.11. ^^ "LSTI job complete" (http://www.3gpp.org/That-s-a-Wrap-LSTI-job-complete). Retrieved 1 March 2012. 12.12. ^^ "LTE/SA "LTE/SAEE Trial InitiatiativeIni tive (LSTI) DeliversDelivers IInitinitialal Results"Results" (http://www .cellular-news. .cellular-news. com/stcom/story/27220.php).ory/27220.php). 7 November 2007. RetrievedRetrieved 1 March 2012. 13.13. ^^ Temple, Stephen. "V"Vintageintage MMobilobiles:es: Samsung SCH-r900 – The wworld’sorld’s ffirstirst LTE MobileMobile (2010)" (http://www.(http://www.gsmhistory.cgsmhistory.com/vintage-- om/vintage mobiles/#samsung_r900_2010). History of GMS: Birth of the mobile revolution. 14.14. ^^ "Samsung Craft, the world’s first 4G LTE phone, now available at MetroPCS" (http://www.unwiredview.com/2010/09/21/samsung-craft-the-worlds-first-4g-lte- phone-now-avail phone-now-availableable-at-metropcs-at-metropcs/). UUnwirednwired ViView.ew. September 21, 2010. 15.15. ^^ "MetroPCS debuts first 4G LTE AndroiAndroidd phone, Samsung Galaxy Indulge" (http://androida(http://androidandme.com/2011/02/cndme.com/2011/02/carriers/metropcs-debuts-first- arriers/metropcs-debuts-first-4g-lte-androi4g-lte-android-phone-d-phone- samsung-galaxy-indulsamsung-galaxy-indulge/).ge/). AAndroidndroid and Me. 2011-02-2011-02-09.09. RetriRetrievedeved 2012-03-15.

16.16. 2012-03-15.^^ "MetroPCS snags first LTE Android phone" (http://www.networkworld.com/news/2011/020911-metropcs-lte-android-phone.html). Networkworld.com. Retrieved 17.17. ^^ "Verizon launches its first LTE handset" (http://www.telegeography.com/products/commsupdate/articles/2011/03/16/verizon-launches-its-first-lte-handset/). Telegeography.com. 2011-03-16. Retrieved 2012-03-15. 18.18. ^^ "HTC ThunderBolThunderBoltt is officialofficiallyly VeVerizon'srizon's ffirstirst LTE handset, come March 17th" (http://www .phonearena.com/news/HTC-ThunderB .phonearena.com/news/HTC-ThunderBolt-iolt-is-ofs-officiaficialllly-Veriy-Verizons-first-zons-first- LTE-handset-come-March-17th_id17455). Phonearena.com. Retrieved 2012-03-15. 19.19. ^^ "Rogers lights up Canada's first LTE network today" (http://www.newswire.ca/en/story/736607/rogers-lights-up-canada-s-first-lte-network-today). CNW Group Ltd. 2011-07-07. Retrieved 2012-10-28. 20.20. ^^ LTE – An End-End-to-Endto-End Description of NetworNetwork ArchitecturAk rchitecturee and Elements (http://sites.google.com/site/l(http://sites.google.com/site/lteencyclopediteencyclopedia/la/lte-network-infrastrte-network-infrastructure-and-elements).ucture-and-elements). 3GPP LTE Encyc lopelopedia.dia. 2009. 21.21. ^^ "A "AT&TT&T commits to LTE-ALTE-Advanceddvanced deployment in 2013, Hesse and Mead unfunfazed"azed" (http://www .engadget.com/2011/11/08/atandt-commits-to-lte-adva .engadget.com/2011/11/08/atandt-commits-to-lte-advanced-nced- deployment-in-2013-hesse-and-mead/). Engadget. 2011-11-08. Retrieved 2012-03-15. 22.22. ^^ LTE – an introduction (http://www.ericsson.com/res/docs/whitepapers/lte_overview.pdf). Ericsson. 2009. eenn..wwiikkiippeeddiiaa..oorrgg//wwiikkii//LLTTEE_ _((tteelleeccoommmmuunniiccaattiioonn)) 77//1100

66//22//1133 LLTTEE((tteelleeccoommmmuunniiccaattiioonn) )- WWiikkiippeeddiiaa, ,tthhe effrreee eeennccyycc llooppeeddiiaa 23.23. ^^ "Long Term Evolution (LTE)" (http://www.motorola.com/web/Business/Solutions/Industry%20Solutions/Service%20Providers/Wireless%20Operators/LTE/_Document/Static%20Files/6833_MotD oc_New.oc_New.pdf).pdf). MotorolaMotorola.. Retrieved ApriAprill 11, 2011. 24.24. ^^ Sesia, Toufik, Baker: LTE – The UMTS Long Term Evolution; From Theory to Practice, page 11. Wiley, 2009. 25.25. ^^ "Evolution of LTE" (http://lteworld.org/blog/lte-advanced-evolution-lte). LTE World. Retrieved October 24, 2011. 26.26. ^^ "Voice and SMS in LTE Technology White Paper, Rohde & Schwarz, 2011" (http://www.rohde-schwarz.com/appnote/1MA197.pdf) 27.27. ^^ [1] (http://www.huawei.com/en/static/hw-094164.pdf) Huawei Communicate Magazine, Issue 61, September 2011. 28.28. ^^ VoLGA whitepaper (http://www.cm-networks.de/volga-a-whitepaper.pdf) 29.29. ^^ Qualcomm Chipset Powers First Suc cesscessfulful VoIP-Over-LTEVoIP-Over-LTE Call WWithith SinglSinglee RadioRadio VoiceVoice Call ContinuityContinuity (http://www.prnews(http://www.prnewswire.com/news-releases/qualcomm- wire.com/news-releases/qualcomm- chipset-powers-first-successful-voip-over-lte-call-with-single-radio-voice-call-continuity-138556144.html) 30.30. ^^ Erricsson - LTE delivers superior voice, too (http://www.ericsson.com/res/thecompany/docs/publications/ericsson_review/2010/lte_e2e.pdf) 31.31. ^^ Fr Fraunhoferaunhofer IISIIS Demos FullFull-HD-HD VoiceVoice Over LTE On AAndroidndroid HandHandsetssets (http://hothardware.com/News /Fraunhofer-II/Fraunhofer-IIS-Demos-FullHS-Demos-FullHD-VD-Voice-Over-LTE-On-oice-Over-LTE-On- Android-Handsets/) 32.32. ^^ Firm Set to Demo HD VoiceVoice over LTE (http://mobilenow.yankeegroup.com/articles/1038(http://mobilenow.yankeegroup.com/articles/103805/firm-set-to-d05/firm-set-to-demo-hd-voice-over-lte/)emo-hd-voice-over-lte/) 33.33. ^^ 1800 MHz – The LTE spectrum band that was almost forgotten (http://www.tolaga.com/pdfArticles/lte1800MHz.pdf) 34.34. ^^ CSL begins dual-band 1800/2600 LTE rolloutrollout (http://www.telecomasia(http://www .telecomasia.net/content/c.net/content/csl-begisl-begins-dual-band-18002600-lte-rollns-dual-band-18002600-lte-rollout)out) 35.35. ^^ Telstra switches on first LTE network on 1800MHz in Australia (http://www.ericsson.com/news/110530_telstra_switches_on_first_lte_network_244188810_c) 36.36. ^^ OptusOptus stilstilll evaluatievaluatingng LTE (http://m.zdnet.com.au/optus-(http://m.zdnet.com.au/optus-stilstill-evall-evaluatiuating-lte-339313233.htm)ng-lte-339313233.htm) 37.37. ^^ "Europe planplanss to resreserveerve 800MH800MHzz frequency band for LTE and WiMAXAX"WiM " (http://whytele(http://whytelecom.ccom.c om/content/europe-plans-reserve-800mhz-from/content/europe-plans-reserve-800mhz-frequency-baequency-band-lte-and-nd-lte-and- wimax). 16 May 2010. Retrieved 11 March 2012. 38.38. ^^ "EC makes official recommendation for 790–862 MHz release" (http://tech.ebu.ch/news/ec-makes-official-recommendation-for-790-29oct09). 29 October 2009. RetriRetrievedeved 11 March 2012. 39. ^ aa bb "Who Owns LTE Patents?" (http://www.ipeg.eu/?p=3529). ipeg. March 6, 2012. Retrieved March 10, 2012. 40.40. ^^ Eli Elizabethzabeth Woyke (2011-09-21). "Identi"Identifyingfying The Tec h Leaders In LTE WiWirelessreless Patents" (http://ww w.w.forbes.forbes.com/scom/siteites/elis/elizabethwoyke/2011/09/21/izabethwoyke/2011/09/21/identifyidentifying-the-ng-the- tech-leaders-in-lte-wireless-patents/). Forbes. Retrieved March 10, 2012. Second comment by the author: "Thus, any analysis of essential LTE patents should take into account more than ETSI declarations."