Difference between revisions of "Mobile Communications/LTE-Advanced - a Further Development of LTE"

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== Wie schnell ist LTE wirklich? ==
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== How fast is LTE really? ==
 
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<br>
Von bereits etablierten kabelbasierten Diensten wie&nbsp; [[Examples_of_Communication_Systems/Allgemeine_Beschreibung_von_DSL|DSL]]&nbsp; (<i>Digital Subscriber Line</i>&nbsp;) ist der Verbraucher gewöhnt, die angebotene Geschwindigkeit (zumindest weitgehend) auch nutzen zu können.
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Consumers are accustomed to being able to use (at least to a large extent) the speed offered by established cable-based services such as&nbsp; [[Examples_of_Communication_Systems/General_Description_of_DSL|DSL]]&nbsp; (<i>Digital Subscriber Line</i>&nbsp;).
*Wie verhält es sich jedoch bei LTE?<br>
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*But what is the situation with LTE?<br>
  
*Welche Datenraten kann der einzelne LTE&ndash;Nutzer tatsächlich erreichen?<br><br>
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*What data rates can the individual LTE&ndash;user actually reach?
  
Für die Provider von Mobilfunksystemen ist es sehr viel schwieriger, konkrete Angaben zur Datenrate zu machen, da bei einer Funkverbindung viele schwer vorhersagbare Einflüsse zu berücksichtigen sind.<br>
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It is much more difficult for the providers of mobile radio systems to provide concrete data rate information, since many influences that are difficult to predict have to be taken into account for a radio connection.<br>
  
Wie bereits im Kapitel&nbsp; [[Mobile_Communications/Technische_Neuerungen_von_LTE#Mehrantennensysteme_.282.29| Technische Neuerungen von LTE]]&nbsp; beschrieben, sind nach der Planung von 2011 im LTE&ndash;Downlink Datenraten bis zu 326 Mbit/s möglich und im Uplink ca. 86 Mbit/s. Bei diesen Zahlen handelt es sich nur um maximal erreichbare Werte. In der Realität wird aber  die Geschwindigkeit von einer Vielzahl von Faktoren beeinflusst. Wir beziehen uns im Folgenden auf den Downlink  &ndash; siehe&nbsp; [Gut10]<ref name='Gut10'>Gutt, E.: ''LTE – eine neue Dimension mobiler Breitbandnutzung.'' [http://www.ltemobile.de/uploads/media/LTE_Einfuehrung_V1.pdf PDF-Dokument im Internet], 2010.</ref>:
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As already described in chapter&nbsp; [[Mobile_Communications/Technical Innovations of LTE# Multiple Antenna Systems|Technical Innovations of LTE]]&nbsp; according to the planning for 2011, data rates of up to 326 Mbit/s are possible in LTE&ndash;Downlink and approx. 86 Mbit/s in Uplink. These figures are only maximum achievable values. In reality, however, the speed is determined by a variety of factors. In the following we refer to the downlink, see&nbsp; [Gut10]<ref name='Gut10'>Gutt, E.: ''LTE - a new dimension of mobile broadband use.'' [http://www.ltemobile.de/uploads/media/LTE_Einfuehrung_V1.pdf PDF document on the Internet], 2010.</ref>:
*Da LTE ein sogenanntes&nbsp; <i>Shared Medium</i>&nbsp; ist, müssen sich alle Teilnehmer einer Zelle die gesamte Datenrate teilen. Zu beachten ist, dass Sprachübertragung oder eine normale Nutzung des Internets weniger Verkehr erzeugt als zum Beispiel&nbsp; <i>Filesharing</i>&nbsp; oder Ähnliches.<br>
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*Since LTE is a so-called&nbsp; <i>Shared Medium</i>&nbsp;, all users of a cell have to share the entire data rate. Note that voice transmission or normal use of the Internet generates less traffic than, for example,&nbsp; <i>Filesharing</i>&nbsp; or similar.<br>
  
*Je schneller sich ein Nutzer bewegt, desto geringer wird die verfügbare Datenrate sein. Elementarer Bestandteil der LTE&ndash;Spezifikation ist, dass für eine Mobilität bis 15 km/h die höchsten Datenraten garantiert werden und bis 300 km/h zumindest noch &bdquo;gute Funktionalität&rdquo;.<br>
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*The faster a user moves, the lower the available data rate will be. An elementary component of the LTE&ndash;specification is that for mobility up to 15 km/h the highest data rates are guaranteed and up to 300 km/h at least still "good functionality".<br>
  
*Die höchste Datenrate wird in nächster Nähe zur Basisstation erreicht. Je weiter ein Teilnehmer von dieser entfernt ist, desto geringer wird die ihm zugewiesene Datenrate, was u. a. auf das Umschalten von 64&ndash;QAM bzw. 16&ndash;QAM auf 4&ndash;QAM (QPSK) zu erklären ist.<br>
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*The highest data rate is achieved in close proximity to the base station. The further away a user is from the base station, the lower the data rate assigned to him, which can be explained by switching from 64&ndash;QAM or 16&ndash;QAM to 4&ndash;QAM (QPSK), among other things.
  
*Abschirmung durch Wände und Gebäude oder Störquellen jeglicher Art begrenzen die erreichbare Datenrate enorm. Optimal wäre eine Sichtverbindung zwischen Empfänger und Basisstation (englisch: &nbsp; <i>Line of Sight</i>, LoS), ein Szenario, das eher selten anzutreffen ist.<br><br>
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*Shielding by walls and buildings or sources of interference of any kind limit the achievable data rate enormously. Optimal would be a Line of Sight connection between receiver and base station a scenario that is rather unusual.<br><br>
  
Die Realität sah im Sommer 2011 wie folgt aus: &nbsp;LTE ist bereits in einigen Ländern (zumindest testweise) verfügbar. Dazu gehören außer dem LTE&ndash;Vorreiter Schweden auch die USA und Deutschland. In verschiedenen Tests wurden Download&ndash;Geschwindigkeiten zwischen 5 und 12 Mbit/s erreicht, bei sehr guten Bedingungen  bis zu 40 Mbit/s. Details finden Sie im Internetartikel&nbsp; [Gol11]<ref name='Gol11'>Goldman, D.: ''AT&T launching 'new' new 4G network.''  [http://money.cnn.com/2011/05/25/technology/att_4g_lte/index.htm PDF&ndash;Dokument im Internet], 2011</ref>.<br>
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The reality in summer 2011 was as follows: &nbsp;LTE is already available in some countries (at least for testing purposes). In addition to LTE&ndash;pioneer Sweden, these include the USA and Germany. In various tests, download&ndash;speeds of between 5 and 12 Mbit/s were achieved, and in very good conditions up to 40 Mbit/s. Details can be found in the Internet article&nbsp; [Gol11]<ref name='Gol11'>Goldman, D.: ''AT&T launching 'new' new 4G network.''  http://money.cnn.com/2011/05/25/technology/att_4g_lte/index.htm PDF&ndash;Document on the Internet], 2011</ref>.<br>
  
Darüber hinaus schien das  LTE&ndash;Netz von 2011 aufgrund von zu hohen Verzögerungszeiten und den daraus resultierenden gelegentlichen Verbindungsunterbrechungen noch nicht bereit, die etablierten kabelgebundenen Internetanschlüsse zu ersetzen. Die Entwicklung auf diesem Gebiet schritt jedoch mit Riesenschritten voran, so dass diese Information vom Sommer 2011 nicht allzu lang aktuell waren.<br>
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Moreover, the 2011 LTE&ndash;network did not seem ready to replace the established wired Internet connections due to excessive delay times and the resulting occasional connection interruptions. However, the development in this area progressed with giant strides, so that this information from summer 2011 was not relevant for very long.<br>
  
== Einige Systemverbesserungen durch LTE–Advanced==
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== Some system improvements through LTE-Advanced==
 
<br>
 
<br>
Während im Sommer 2011 die ersten LTE&ndash;Systeme entsprechend dem Release 8 vom Dezember 2008 langsam auf den Markt kamen, stand der Nachfolger bereits vor der Tür. Das im Juni 2011 fertig gestellte Release 10 des &bdquo;3GPP&rdquo; ist ''Long Term Evolution&ndash;Advanced'', oder kurz &nbsp;$\rm LTE-A$. Es erfüllt als erste Technologie die Anforderungen der ITU (<i>International Telecommunication Union</i>) an einen 4G&ndash;Standard. Eine Zusammenstellung dieser Anforderungen &ndash; auch ''IMT&ndash;Advanced'' genannt &ndash;  finden Sie  sehr detailliert in einem [http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2134-2008-PDF-E.pdf ITU&ndash;Artikel (PDF).]<br>
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While the first LTE&ndash;systems corresponding to Release 8 of December 2008 slowly came onto the market in summer 2011, the successor was already on the doorstep. The Release 10 of the "3GPP" completed in June 2011 is ''Long Term Evolution&ndash;Advanced'', or in short &nbsp;$\rm LTE-A$. It is the first technology to meet the requirements of the ITU (<i>International Telecommunication Union</i>) for a 4G&ndash;standard. A summary of these requirements, also called ''IMT&ndash;Advanced'', can be found in great detail in an [http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2134-2008-PDF-E.pdf ITU&ndash;Article (PDF).]<br>
  
Ohne Anspruch auf Vollständigkeit werden hier einige Eigenschaften von LTE&ndash;Advanced genannt:
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Without claiming to be exhaustive, some of the features of LTE&ndash;Advanced are mentioned here:
*Die Datenrate soll bei geringer Bewegung des Teilnehmers bis zu 1 Gbit/s betragen, bei schneller Bewegung bis zu 100 Mbit/s. Um diese hohen Datenraten zu erreichen, wurden einige neue technische Spezifikationen getroffen, auf die hier kurz eingegangen werden soll.<br>
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*The data rate should be up to 1 Gbit/s with little movement of the user and up to 100 Mbit/s with fast movement. In order to achieve these high data rates, some new technical specifications have been made, which will be briefly discussed here.<br>
  
*LTE&ndash;Advanced unterstützt Bandbreiten bis maximal 100 MHz, während die LTE&ndash;Spezifizierung (nach Release 8) nur 20 MHz vorsieht. Dabei müssen die FDD&ndash;Spektren nicht mehr symmetrisch zwischen Uplink und Downlink aufgeteilt sein. Es kann also zum Beispiel für den Downlink eine höhere Kanalbandbreite verwendet werden als für den Uplink, was der normalen Nutzung des mobilen Internets mit einem Smartphone entspricht.<br>
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*LTE&ndash;Advanced supports bandwidths up to 100 MHz maximum, while the LTE&ndash;specification (after Release 8) provides only 20 MHz. The FDD&ndash;spectra no longer have to be divided symmetrically between uplink and downlink. For example, a higher channel bandwidth can be used for the downlink than for the uplink, which corresponds to the normal use of the mobile Internet with a smartphone.<br>
  
*Im Uplink von LTE&ndash;Advanced wird ebenfalls&nbsp; [[Mobile_Communications/Die_Anwendung_von_OFDMA_und_SC-FDMA_in_LTE#Funktionsweise_von_SC.E2.80.93FDMA|SC&ndash;FDMA]]&nbsp; verwendet. Da das 3GPP&ndash;Konsortium mit der SC&ndash;FDMA&ndash;Übertragung bei LTE nicht zufrieden war, wurden aber einige wesentliche Verbesserungen im Ablauf erarbeitet, .<br>
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*In the uplink of LTE&ndash;Advanced &nbsp; [[Mobile_Communications/The_Application_of_OFDMA_and_SC-FDMA_in_LTE#Functionality_of_SC.E2.80.93FDMA|SC&ndash;FDMA]]&nbsp; is also used. Since the 3GPP&ndash;Consortium was not satisfied with the SC&ndash;FDMA transmission in LTE, some essential improvements in the process were developed.<br>
  
*Eine weitere interessante Neuheit stellt die Einführung sogenannter &bdquo;Relay Nodes&rdquo; dar. Ein solches&nbsp; <i>Relay Node</i>&nbsp; (RN) wird am Rand einer Zelle  aufgestellt, um für bessere Übertragungsqualität an den Grenzen einer Zelle zu sorgen und so die Reichweite der Zelle zu erhöhen.<br><br>
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*Another interesting novelty is the introduction of so-called "Relay Nodes". Such a&nbsp; <i>Relay Node</i>&nbsp; (RN) is placed at the edge of a cell to provide better transmission quality at the boundaries of a cell and thus increase the range of the cell.<br><br>
  
[[File:P ID2295 LTE T 4 5 S2 v1.png|right|frame|Funktionsweise der Relay Nodes]]
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[[File:P ID2295 LTE T 4 5 S2 v1.png|right|frame|Functionality of Relay Nodes]]
Ein&nbsp; <i>Relay Node</i>&nbsp; sieht für ein Endgerät aus wie eine normale Basisstation (<i>eNodeB</i>). Sie muss aber nur ein relativ kleines Einsatzgebiet versorgen und muss deshalb nicht aufwändig an das Backbone angeschlossen werden. In den meisten Fällen ist ein Relay Node über Richtfunk mit der nächsten Basisstation verbunden.
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A&nbsp; <i>Relay Node</i>&nbsp; looks like a normal base station for a terminal device (<i>eNodeB</i>). However, it only has to supply a relatively small area of operation and therefore does not need to be connected to the backbone in a complicated way. In most cases a relay node is connected to the next base station via directional radio.
  
Auf diese Art und Weise werden ohne großen Aufwand hohe Datenraten und gute Übertragungsqualität ohne Unterbrechungen gewährleistet. Durch Erhöhen der räumlichen Nähe zu den Basisstationen wird damit auch die Empfangsqualität in Gebäuden verbessert.
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In this way, high data rates and good transmission quality without interruptions are guaranteed without great effort. By increasing the physical proximity to the base stations, the reception quality in buildings is also improved.
  
Ein weiteres bei LTE&ndash;A hinzugekommenes Feature ist unter der Bezeichnung&nbsp; <i>Coordinated Multiple Point Transmission and Reception</i>&nbsp; (CoMP) bekannt. Damit versucht man, den störenden Einfluss von Interzellinterferenzen zu reduzieren. Mit intelligentem Scheduling über mehrere Basisstationen hinweg gelingt es sogar, Interzellinterferenz nutzbar zu machen. Dabei steht die Information für ein Endgerät an zwei benachbarten Basisstationen zur Verfügung und kann gleichzeitig übertragen werden. Details zur CoMP&ndash;Technik finden sich zum Beispiel in dem Internet&ndash;Artikel&nbsp; [Wan13]<ref name='Wan13'>Wannstrom, J.: ''LTE&ndash;Advanced''.  [http://www.3gpp.org/technologies/keywords-acronyms/97-lte-advanced PDF&ndash;Dokument im Internet, 2011]</ref>&nbsp; von 3gpp.<br>
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Another feature added to LTE&ndash;A is known as&nbsp; <i>Coordinated Multiple Point Transmission and Reception</i>&nbsp; (CoMP). This is an attempt to reduce the disturbing influence of intercell interference. With intelligent scheduling across several base stations, it is even possible to make intercell interference usable. The information for a terminal device is available at two adjacent base stations and can be transmitted simultaneously. Details on CoMP&ndash;technology can be found, for example, in the internet article&nbsp; [Wan13]<ref name='Wan13'>Wannstrom, J.: ''LTE&ndash;Advanced''.  http://www.3gpp.org/technologies/keywords-acronyms/97-lte-advanced PDF&ndash;Document on the Internet, 2011]</ref>&nbsp; from 3gpp.<br>
  
  
 
{{BlaueBox|TEXT=   
 
{{BlaueBox|TEXT=   
$\text{Zwischenstand von 2011:}$&nbsp;  
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$\text{Intermediate status of 2011:}$&nbsp;*Thanks to the above measures in combination with many other improvements, primarily the introduction of 4&times;4&ndash;MIMO for the uplink and 8&times;8&ndash;MIMO in the downlink, it is possible to significantly increase the spectral efficiency (i.e. the transferable flow of information in one Hertz bandwidth within one second) of LTE&ndash;A compared to LTE, namely in the <i>downlink</i> from 15 bit/s/Hz&nbsp; to &nbsp;$\text{30 bit/s/Hz}$&nbsp; and in the <i>uplink</i> from 3. 75 bit/s/Hz to &nbsp;$\text{15 bit/s/Hz}$.<br>
*Durch die genannten Maßnahmen in Kombination mit vielen weiteren Verbesserungen &ndash; in erster Linie die Einführung von 4&times;4&ndash;MIMO für den Uplink und 8&times;8&ndash;MIMO im Downlink  &ndash; gelingt es, die spektrale Effizienz (darunter versteht man den übertragbaren Informationsfluss in einem Hertz Bandbreite innerhalb einer Sekunde) von LTE&ndash;A gegenüber LTE signifikant zu erhöhen, und zwar im <i>Downlink</i> von 15 bit/s/Hz&nbsp; auf &nbsp;$\text{30 bit/s/Hz}$&nbsp; und im <i>Uplink</i> von 3.75 bit/s/Hz auf &nbsp;$\text{15 bit/s/Hz}$.<br>
 
  
*Natürlich muss zusätzlich auch die Rückwärtskompatibilität zum vorangegangenen Standard LTE und zu früheren Mobilfunksystemen gewährleistet werden. Auch mit einem UMTS&ndash;Handy sollte man sich in ein LTE&ndash;Netz einwählen können, auch wenn man die LTE&ndash;spezifischen Features nicht nutzen kann.<br>
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*Of course, backwards compatibility with the previous LTE standard and previous mobile phone systems must also be guaranteed. Also with a UMTS&ndash;cell phone one should be able to dial into a LTE&ndash;network, even if one cannot use the LTE specific features.<br>
  
*Anfang Juni 2011 gab es die ersten Tests zu LTE&ndash;Advanced. Schweden, das bereits das erste kommerzielle LTE&ndash;Netz aufgebaut hat, übernahm auch hier wieder die Vorreiterrolle. Die Fa. Ericsson demonstrierte erstmals ein Testsystem mit praxistauglichen, handelsüblichen Endgeräten und begann 2013 mit der kommerziellen Nutzung von LTE&ndash;Advanced.  
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*At the beginning of June 2011 the first tests of LTE&ndash;Advanced were conducted. Sweden, which has already set up the first commercial LTE&ndash;network, once again took the lead. Ericsson demonstrated for the first time a test system with practical, commercially available terminals and began commercial use of LTE&ndash;Advanced in 2013.  
*In einem Youtube&ndash;Video ist ein LTE&ndash;Test in einem fahrenden Kleinbus zu sehen, bei dem Datenraten von über 900 Mbit/s im Downlink und 300 Mbit/s im Uplink erreicht wurden.}}<br>
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*In a YouTube&ndash;video, an LTE&ndash;test can be seen in a moving minibus, in which data rates of over 900 Mbit/s in the downlink and 300 Mbit/s in the uplink were achieved.}}<br>
  
== Standards in Konkurrenz zu LTE bzw. LTE–Advanced ==
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== Standards in competition with LTE or LTE-Advanced ==
 
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Neben dem vom 3GPP&ndash;Konsortium spezifizierten LTE gibt es weitere Standards, die der schnellen mobilen Datenübertragung dienen sollen. Hier wird kurz auf die zwei wichtigsten eingegangen:<br>
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In addition to the LTE specified by the 3GPP&ndash;consortium, there are other standards that are intended to serve the purpose of fast mobile data transmission. The two most important ones are briefly discussed here:<br>
  
  
'''cdma2000''' (oder ''IS&ndash;2000''&nbsp;) und dessen Weiterentwicklung '''UMB''' (<i>Ultra Mobile Broadband</i>&nbsp;):<br>
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'''cdma2000''' (or ''IS&ndash;2000''&nbsp;) and its further development '''UMB''' (<i>Ultra Mobile Broadband</i>&nbsp;):<br>
  
Hierbei handelt es sich um einen Mobilfunkstandard der dritten Generation, der vom&nbsp; [http://www.3gpp2.org/ 3GPP2]&nbsp; (<i>Third Generation Partnership Project 2</i>&nbsp;) spezifiziert und weiterentwickelt wurde. Weitere Informationen zu&nbsp; ''cdma2000''&nbsp; finden Sie im Abschnitt&nbsp; [[Mobile_Communications/Die_Charakteristika_von_UMTS#Der_IMT.E2.80.932000.E2.80.93Standard|IMT&ndash;2000&ndash;Standard]]&nbsp; des Buches &bdquo;Beispiele von Nachrichtensystemen&rdquo;. <br>
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This is a third-generation mobile communications standard that was specified and further developed by&nbsp; [http://www.3gpp2.org/ 3GPP2]&nbsp; (<i>Third Generation Partnership Project 2</i>&nbsp;) Further information on&nbsp; ''cdma2000''&nbsp; can be found in the section&nbsp; [[Mobile_Communications/The_Characteristics_of_UMTS#The_IMT.E2.80.932000.E2.80.93Standard|IMT&ndash;2000&ndash;Standard]]&nbsp; of the book "Examples of communication systems". <br>
  
Über die Weiterentwicklung dieses Standards ist weitaus weniger bekannt als zu LTE. Erwähnenswert ist, dass es für&nbsp; ''cdma2000''&nbsp; und&nbsp; ''UMB''&nbsp; einen ausschließlich für die Datenübertragung spezifizierten Substandard gibt. Der Kölner Telekommunikationsanbieter&nbsp; <i>NetCologne</i>&nbsp; hat seit 2011 auf dieser Basis mobiles Internet im Bereich um 450 MHz angeboten. Darüber hinaus ist cdma2000 in Deutschland unbedeutend.<br>
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Far less is known about the further development of this standard than about LTE. It is worth mentioning that for&nbsp; ''cdma2000''&nbsp; and&nbsp; ''UMB''&nbsp; there is a substandard specified exclusively for data transmission. The Cologne telecommunications provider&nbsp; <i>NetCologne</i>&nbsp; has been offering mobile Internet in the 450 MHz range on this basis since 2011. Furthermore, cdma2000 is insignificant in Germany.<br>
  
<i>Anmerkung:</i> &nbsp; Das &bdquo;3GPP2&rdquo; wurde nahezu zeitgleich mit dem fast namensgleichen&nbsp; [http://www.3gpp.org/ 3GPP]&nbsp; im Dezember 1998 gegründet, offenbar aufgrund von ideologischen Differenzen.<br><br>
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<i>Note:</i> &nbsp; The "3GPP2" was founded almost at the same time as the almost identically named&nbsp; [http://www.3gpp.org/ 3GPP]&nbsp; in December 1998, obviously due to ideological differences.<br><br>
  
 
'''WiMAX''' (<i>Worldwide Interoperability for Microwave Access</i>&nbsp;):<br>
 
'''WiMAX''' (<i>Worldwide Interoperability for Microwave Access</i>&nbsp;):<br>
  
Unter dieser Bezeichnung versteht man eine auf dem&nbsp; ''IEEE&ndash;Standard 802.16''&nbsp; basierende drahtlose Übertragungstechnik. Sie gehört damit wie auch WLAN (802.11) und Ethernet (802.3) zur Familie der 802&ndash;Standards. Es gibt zwei verschiedene Unterspezifikationen zu WiMAX, nämlich
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This term refers to a wireless transmission technology based on the&nbsp; ''IEEE&ndash;Standard 802.16''&nbsp;. It belongs to the family of the 802&ndash;standards like WLAN (802.11) and Ethernet (802.3). There are two different sub-specifications to WiMAX, namely
*einen für den Betrieb einer statischen Verbindung, die kein Handover erlaubt, und<br>
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*one for operating a static connection that does not allow handover, and<br>
  
*einen für den mobilen Betrieb, der UMTS und LTE Konkurrenz machen soll.<br><br>
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*one for the mobile operation, which is to compete with UMTS and LTE.<br><br>
  
Das Potential der statischen WiMAX&ndash;Verbindungen liegt hauptsächlich in der der großen Reichweite bei trotzdem vergleichsweise hoher Datenrate. Aus diesem Grund wurde statisches WiMAX zunächst als DSL&ndash;Alternative für dünn besiedelte Gebiete gehandelt. So sind bei einer Sichtverbindung zwischen Sender und Empfänger (<i>Line of Sight</i>, LoS) über 15 Kilometer etwa 4.5 Mbit/s möglich. In urbanem Gebiet ohne Sichtverbindung wird für WiMAX immerhin noch eine Reichweite von ca. 600 Meter angegeben, ein deutlich besserer Wert als die 100 Meter, die WLAN typischerweise bietet.<br>
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The potential of the static WiMAX&ndash;connections lies mainly in the long range with nevertheless comparatively high data rate. For this reason, static WiMAX was initially traded as DSL&ndash;alternative for thinly populated areas. For example, with a Line of Sight (LoS) connection between transmitter and receiver over 15 kilometers, about 4.5 Mbit/s are possible. In urban areas without line of sight, WiMAX still has a range of about 600 meters, a much better value than the 100 meters typically offered by WLAN.<br>
  
Momentan (2011) wird auch an einer Weiterentwicklung namens &bdquo;WiMAX2&rdquo; gearbeitet. Nach Aussage der Initiatoren ist WiMAX2 in der mobilen Version ein 4G&ndash;Standard, der genau wie LTE&ndash;Advanced Datenraten bis zu 1 Gbit/s erreichen kann. Ende 2011 soll WiMAX2 in die Praxis umgesetzt werden. Ob es zu diesem Termin und mit der prognostizierten Datenrate klappt, wird sich zeigen.<br>
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At the moment (2011) we are also working on a further development called "WiMAX2". According to the initiators, WiMAX2 in the mobile version is a 4G&ndash;standard which, just like LTE&ndash;Advanced, can achieve data rates of up to 1 Gbit/s. WiMAX2 is to be implemented in practice by the end of 2011. It remains to be seen whether it will work on this date and with the predicted data rate.
  
In Deutschland spielt WiMAX (derzeit noch) keine große Rolle, da sowohl die Bundesregierung in ihrer Breitbandoffensive als auch alle großen Mobilfunkbetreiber&nbsp; <i>Long Term Evolution</i>&nbsp; (LTE bzw. LTE&ndash;A) als Zukunft der mobilen Datenübertragung ausgerufen haben.<br>
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In Germany, WiMAX does not play a major role (at present), since both the German government in its broadband offensive and all major mobile phone operators&nbsp; <i>Long Term Evolution</i>&nbsp; (LTE or LTE&ndash;A) have declared it to be the future of mobile data transmission.<br>
  
== Meilensteine der Entwicklung von LTE und LTE–Advanced ==
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== Milestones in the development of LTE and LTE-Advanced ==
 
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<br>
Abschließend noch ein kurzer Überblick über einige Meilensteine bei der Entwicklung hin zu LTE aus Sicht des Jahres 2011:
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Finally, a brief overview of some milestones in the development towards LTE from the perspective of 2011:
*'''2004'''&nbsp; &nbsp; Das japanische Telekommunikationsunternehmen&nbsp; [https://www.nttdocomo.co.jp/english/index.html NTT DoCoMo]&nbsp; schlägt LTE als neuen internationalen Mobilfunkstandard vor.<br>
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*'''2004'''&nbsp; &nbsp; The Japanese telecommunications company&nbsp; [https://www.nttdocomo.co.jp/english/index.html NTT DoCoMo]&nbsp; proposes LTE as the new international mobile communications standard.<br>
  
*'''09/2006'''&nbsp; &nbsp; Nokia Siemens Networks (NSN) stellt zusammen mit&nbsp; [http://www.nomor.de/ Nomor Research]&nbsp; erstmals einen Emulator eines LTE&ndash;Netzes vor. Zur Demonstration wird ein HD&ndash;Video übertragen und zwei Nutzer spielen ein interaktives Onlinespiel.<br>
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*'''09/2006'''&nbsp; &nbsp; Nokia Siemens Networks (NSN) presents together with&nbsp; [http://www.nomor.de/ Nomor Research]&nbsp; for the first time an emulator of an LTE&ndash;network. For demonstration purposes, a HD&ndash;video is transmitted and two users play an interactive online game.<br>
  
*'''02/2007'''&nbsp; &nbsp; Auf dem&nbsp; <i>3GSM World Congress</i>, der weltweit größten Mobilfunkmesse, demonstriert das schwedische Unternehmen&nbsp; [https://www.ericsson.com/ Ericsson]&nbsp; ein LTE&ndash;System mit 144 Mbit/s. <br>
+
*'''02/2007'''&nbsp; &nbsp; At the&nbsp; <i>3GSM World Congress</i>, the world's largest mobile phone trade fair, the Swedish company&nbsp; [https://www.ericsson.com/ Ericsson]&nbsp; will demonstrate an LTE&ndash;system with 144 Mbit/s. <br>
  
*'''04/2008'''&nbsp; &nbsp; [https://de.wikipedia.org/wiki/NTT_DOCOMO DoCoMo]&nbsp; demonstriert eine LTE&ndash;Datenrate von 250 Mbit/s. Nahezu zeitgleich erreicht&nbsp; [https://de.wikipedia.org/wiki/Nortel Nortel Networks Corp.]&nbsp; (Kanada) bei einer Fahrzeuggeschwindigkeit von 100 km/h immerhin  50 Mbit/s.<br>
+
*'''04/2008'''&nbsp; &nbsp; [https://de.wikipedia.org/wiki/NTT_DOCOMO DoCoMo]&nbsp; demonstrates an LTE data rate of 250 Mbit/s. Almost simultaneously &nbsp; [https://de.wikipedia.org/wiki/Nortel Nortel Networks Corp.]&nbsp; (Canada) achieved a data rate in vehicle speed of 100 km/h of at least 50 Mbit/s.<br>
  
*'''10/2008'''&nbsp; &nbsp; Test des ersten funktionsfähigen LTE&ndash;Modems durch Ericsson in Stockholm. Dieser Termin ist der Startschuss für die kommerzielle Nutzung von LTE.<br>
+
*'''10/2008'''&nbsp; &nbsp; Test of the first working LTE&ndash;modem by Ericsson in Stockholm. This date is the starting point for the commercial use of LTE.<br>
  
*'''12/2008'''&nbsp; &nbsp; Fertigstellung der Release 8 des 3GPP, gleichbedeutend mit LTE. Das Unternehmen&nbsp; [http://www.lg.com/de LG Electronics]&nbsp; entwickelt den ersten LTE&ndash;Chip für Mobiltelefone.<br>
+
*'''12/2008'''&nbsp; &nbsp; Completion of Release 8 of 3GPP, synonymous with LTE. The company&nbsp; [http://www.lg.com/de LG Electronics]&nbsp; develops the first LTE&ndash;chip for cell phones.<br>
  
*'''03/2009'''&nbsp; &nbsp; Auf der CeBIT in Hannover zeigt&nbsp; [https://www.t-mobile.de/ T&ndash;Mobile]&nbsp; Videokonferenzen und Onlinespiele aus einem fahrenden Auto heraus. <br>
+
*'''03/2009'''&nbsp; &nbsp; At the CeBIT in Hanover, Germany,&nbsp; [https://www.t-mobile.de/ T&ndash;Mobile]&nbsp; Video conferencing and online games from a moving car. <br>
  
*'''12/2009'''&nbsp; &nbsp; Das weltweit erste kommerzielle LTE&ndash;Netz startet in der Stockholmer Innenstadt, nur 14 Monate nach Beginn der Testphase.<br>
+
*'''12/2009'''&nbsp; &nbsp; The world's first commercial LTE&ndash;network starts in downtown Stockholm, only 14 months after the start of the test phase.<br>
  
*'''04/2010'''&nbsp; &nbsp; 3GPP beginnt mit der Spezifikation von Release 10, gleichbedeutend mit LTE&ndash;A.<br>
+
*'''04/2010'''&nbsp; &nbsp; 3GPP begins with the specification of Release 10, synonymous with LTE&ndash;A.<br>
  
*'''05/2010'''&nbsp; &nbsp; Die LTE&ndash;Frequenzauktion in Deutschland endet. Der Erlös ist mit 4.4 Milliarden Euro deutlich geringer, als von den Experten erwartet und von Politikern erhofft. <br>
+
*'''05/2010''&nbsp; &nbsp; The LTE&ndash;frequency auction in Germany ends. At 4.4 billion euros, the proceeds are significantly lower than experts had expected and politicians had hoped for. <br>
  
*'''08/2010'''&nbsp; &nbsp; T-Mobile baut in Kyritz die erste kommerziell nutzbare LTE&ndash;Basisstation Deutschlands. Für einen funktionierenden Betrieb fehlen noch passende Endgeräte.<br>
+
*'''08/2010'''&nbsp; &nbsp; T-Mobile is building Germany's first commercially usable LTE&ndash;base station in Kyritz For a functioning operation, suitable terminals are still missing.<br>
  
*'''12/2010'''&nbsp; &nbsp; In Deutschland laufen die ersten größeren Pilottests in den Netzen von Telekom,&nbsp; [https://www.o2online.de/ O2]&nbsp; und&nbsp; [http://www.vodafone.de/ Vodafone]. Inzwischen sind entsprechende LTE&ndash;Router verfügbar.<br>
+
*'''12/2010'''&nbsp; &nbsp; In Germany, the first major pilot tests are running on the networks of Telekom,&nbsp; [https://www.o2online.de/ O2]&nbsp; and&nbsp; [http://www.vodafone.de/ Vodafone]. In the meantime, corresponding LTE&ndash;routers are available.
  
*'''02/2011'''&nbsp; &nbsp; In Südkorea werden erste erfolgreiche Tests mit dem Nachfolger LTE&ndash;Advanced durchgeführt.<br>
+
*'''02/2011'''&nbsp; &nbsp; In South Korea the first successful tests with the successor LTE&ndash;Advanced are being conducted.<br>
  
*'''03/2011'''&nbsp; &nbsp; Das 3GPP Release 10 ist fertiggestellt.<br>
+
*'''03/2011'''&nbsp; &nbsp; The 3GPP Release 10 is completed.<br>
  
*'''06/2011'''&nbsp; &nbsp; Start des ersten deutschen LTE&ndash;Netzes in Köln. Bis Mitte 2012 sorgt die Telekom in 100 weiteren Städten für eine großflächige Verbreitung von LTE.<br>
+
*'''06/2011''&nbsp; &nbsp; Launch of the first German LTE&ndash;network in Cologne. By mid-2012, Deutsche Telekom will ensure that LTE&ndash;network is rolled out across a wide area in 100 additional cities.<br>
  
==Aufgabe zum Kapitel==
+
==Exercise to chapter==
 
<br>
 
<br>
[[Aufgaben:4.5 LTE vs. LTE–Advanced|Aufgabe 4.5: LTE vs. LTE–Advanced]]
+
[[Aufgaben:Exercise 4.5: LTE vs LTE-Advanced]]
  
==Quellenverzeichnis==
+
==List of Sources==
  
 
<references/>
 
<references/>

Revision as of 00:57, 19 October 2020



How fast is LTE really?


Consumers are accustomed to being able to use (at least to a large extent) the speed offered by established cable-based services such as  DSL  (Digital Subscriber Line ).

  • But what is the situation with LTE?
  • What data rates can the individual LTE–user actually reach?

It is much more difficult for the providers of mobile radio systems to provide concrete data rate information, since many influences that are difficult to predict have to be taken into account for a radio connection.

As already described in chapter  Technical Innovations of LTE  according to the planning for 2011, data rates of up to 326 Mbit/s are possible in LTE–Downlink and approx. 86 Mbit/s in Uplink. These figures are only maximum achievable values. In reality, however, the speed is determined by a variety of factors. In the following we refer to the downlink, see  [Gut10][1]:

  • Since LTE is a so-called  Shared Medium , all users of a cell have to share the entire data rate. Note that voice transmission or normal use of the Internet generates less traffic than, for example,  Filesharing  or similar.
  • The faster a user moves, the lower the available data rate will be. An elementary component of the LTE–specification is that for mobility up to 15 km/h the highest data rates are guaranteed and up to 300 km/h at least still "good functionality".
  • The highest data rate is achieved in close proximity to the base station. The further away a user is from the base station, the lower the data rate assigned to him, which can be explained by switching from 64–QAM or 16–QAM to 4–QAM (QPSK), among other things.
  • Shielding by walls and buildings or sources of interference of any kind limit the achievable data rate enormously. Optimal would be a Line of Sight connection between receiver and base station a scenario that is rather unusual.

The reality in summer 2011 was as follows:  LTE is already available in some countries (at least for testing purposes). In addition to LTE–pioneer Sweden, these include the USA and Germany. In various tests, download–speeds of between 5 and 12 Mbit/s were achieved, and in very good conditions up to 40 Mbit/s. Details can be found in the Internet article  [Gol11][2].

Moreover, the 2011 LTE–network did not seem ready to replace the established wired Internet connections due to excessive delay times and the resulting occasional connection interruptions. However, the development in this area progressed with giant strides, so that this information from summer 2011 was not relevant for very long.

Some system improvements through LTE-Advanced


While the first LTE–systems corresponding to Release 8 of December 2008 slowly came onto the market in summer 2011, the successor was already on the doorstep. The Release 10 of the "3GPP" completed in June 2011 is Long Term Evolution–Advanced, or in short  $\rm LTE-A$. It is the first technology to meet the requirements of the ITU (International Telecommunication Union) for a 4G–standard. A summary of these requirements, also called IMT–Advanced, can be found in great detail in an ITU–Article (PDF).

Without claiming to be exhaustive, some of the features of LTE–Advanced are mentioned here:

  • The data rate should be up to 1 Gbit/s with little movement of the user and up to 100 Mbit/s with fast movement. In order to achieve these high data rates, some new technical specifications have been made, which will be briefly discussed here.
  • LTE–Advanced supports bandwidths up to 100 MHz maximum, while the LTE–specification (after Release 8) provides only 20 MHz. The FDD–spectra no longer have to be divided symmetrically between uplink and downlink. For example, a higher channel bandwidth can be used for the downlink than for the uplink, which corresponds to the normal use of the mobile Internet with a smartphone.
  • In the uplink of LTE–Advanced   SC–FDMA  is also used. Since the 3GPP–Consortium was not satisfied with the SC–FDMA transmission in LTE, some essential improvements in the process were developed.
  • Another interesting novelty is the introduction of so-called "Relay Nodes". Such a  Relay Node  (RN) is placed at the edge of a cell to provide better transmission quality at the boundaries of a cell and thus increase the range of the cell.

Functionality of Relay Nodes

Relay Node  looks like a normal base station for a terminal device (eNodeB). However, it only has to supply a relatively small area of operation and therefore does not need to be connected to the backbone in a complicated way. In most cases a relay node is connected to the next base station via directional radio.

In this way, high data rates and good transmission quality without interruptions are guaranteed without great effort. By increasing the physical proximity to the base stations, the reception quality in buildings is also improved.

Another feature added to LTE–A is known as  Coordinated Multiple Point Transmission and Reception  (CoMP). This is an attempt to reduce the disturbing influence of intercell interference. With intelligent scheduling across several base stations, it is even possible to make intercell interference usable. The information for a terminal device is available at two adjacent base stations and can be transmitted simultaneously. Details on CoMP–technology can be found, for example, in the internet article  [Wan13][3]  from 3gpp.


$\text{Intermediate status of 2011:}$ *Thanks to the above measures in combination with many other improvements, primarily the introduction of 4×4–MIMO for the uplink and 8×8–MIMO in the downlink, it is possible to significantly increase the spectral efficiency (i.e. the transferable flow of information in one Hertz bandwidth within one second) of LTE–A compared to LTE, namely in the downlink from 15 bit/s/Hz  to  $\text{30 bit/s/Hz}$  and in the uplink from 3. 75 bit/s/Hz to  $\text{15 bit/s/Hz}$.

  • Of course, backwards compatibility with the previous LTE standard and previous mobile phone systems must also be guaranteed. Also with a UMTS–cell phone one should be able to dial into a LTE–network, even if one cannot use the LTE specific features.
  • At the beginning of June 2011 the first tests of LTE–Advanced were conducted. Sweden, which has already set up the first commercial LTE–network, once again took the lead. Ericsson demonstrated for the first time a test system with practical, commercially available terminals and began commercial use of LTE–Advanced in 2013.
  • In a YouTube–video, an LTE–test can be seen in a moving minibus, in which data rates of over 900 Mbit/s in the downlink and 300 Mbit/s in the uplink were achieved.


Standards in competition with LTE or LTE-Advanced


In addition to the LTE specified by the 3GPP–consortium, there are other standards that are intended to serve the purpose of fast mobile data transmission. The two most important ones are briefly discussed here:


cdma2000 (or IS–2000 ) and its further development UMB (Ultra Mobile Broadband ):

This is a third-generation mobile communications standard that was specified and further developed by  3GPP2  (Third Generation Partnership Project 2 ) Further information on  cdma2000  can be found in the section  IMT–2000–Standard  of the book "Examples of communication systems".

Far less is known about the further development of this standard than about LTE. It is worth mentioning that for  cdma2000  and  UMB  there is a substandard specified exclusively for data transmission. The Cologne telecommunications provider  NetCologne  has been offering mobile Internet in the 450 MHz range on this basis since 2011. Furthermore, cdma2000 is insignificant in Germany.

Note:   The "3GPP2" was founded almost at the same time as the almost identically named  3GPP  in December 1998, obviously due to ideological differences.

WiMAX (Worldwide Interoperability for Microwave Access ):

This term refers to a wireless transmission technology based on the  IEEE–Standard 802.16 . It belongs to the family of the 802–standards like WLAN (802.11) and Ethernet (802.3). There are two different sub-specifications to WiMAX, namely

  • one for operating a static connection that does not allow handover, and
  • one for the mobile operation, which is to compete with UMTS and LTE.

The potential of the static WiMAX–connections lies mainly in the long range with nevertheless comparatively high data rate. For this reason, static WiMAX was initially traded as DSL–alternative for thinly populated areas. For example, with a Line of Sight (LoS) connection between transmitter and receiver over 15 kilometers, about 4.5 Mbit/s are possible. In urban areas without line of sight, WiMAX still has a range of about 600 meters, a much better value than the 100 meters typically offered by WLAN.

At the moment (2011) we are also working on a further development called "WiMAX2". According to the initiators, WiMAX2 in the mobile version is a 4G–standard which, just like LTE–Advanced, can achieve data rates of up to 1 Gbit/s. WiMAX2 is to be implemented in practice by the end of 2011. It remains to be seen whether it will work on this date and with the predicted data rate.

In Germany, WiMAX does not play a major role (at present), since both the German government in its broadband offensive and all major mobile phone operators  Long Term Evolution  (LTE or LTE–A) have declared it to be the future of mobile data transmission.

Milestones in the development of LTE and LTE-Advanced


Finally, a brief overview of some milestones in the development towards LTE from the perspective of 2011:

  • 2004    The Japanese telecommunications company  NTT DoCoMo  proposes LTE as the new international mobile communications standard.
  • 09/2006    Nokia Siemens Networks (NSN) presents together with  Nomor Research  for the first time an emulator of an LTE–network. For demonstration purposes, a HD–video is transmitted and two users play an interactive online game.
  • 02/2007    At the  3GSM World Congress, the world's largest mobile phone trade fair, the Swedish company  Ericsson  will demonstrate an LTE–system with 144 Mbit/s.
  • 04/2008    DoCoMo  demonstrates an LTE data rate of 250 Mbit/s. Almost simultaneously   Nortel Networks Corp.  (Canada) achieved a data rate in vehicle speed of 100 km/h of at least 50 Mbit/s.
  • 10/2008    Test of the first working LTE–modem by Ericsson in Stockholm. This date is the starting point for the commercial use of LTE.
  • 12/2008    Completion of Release 8 of 3GPP, synonymous with LTE. The company  LG Electronics  develops the first LTE–chip for cell phones.
  • 03/2009    At the CeBIT in Hanover, Germany,  T–Mobile  Video conferencing and online games from a moving car.
  • 12/2009    The world's first commercial LTE–network starts in downtown Stockholm, only 14 months after the start of the test phase.
  • 04/2010    3GPP begins with the specification of Release 10, synonymous with LTE–A.
  • '05/2010    The LTE–frequency auction in Germany ends. At 4.4 billion euros, the proceeds are significantly lower than experts had expected and politicians had hoped for.
  • 08/2010    T-Mobile is building Germany's first commercially usable LTE–base station in Kyritz For a functioning operation, suitable terminals are still missing.
  • 12/2010    In Germany, the first major pilot tests are running on the networks of Telekom,  O2  and  Vodafone. In the meantime, corresponding LTE–routers are available.
  • 02/2011    In South Korea the first successful tests with the successor LTE–Advanced are being conducted.
  • 03/2011    The 3GPP Release 10 is completed.
  • '06/2011    Launch of the first German LTE–network in Cologne. By mid-2012, Deutsche Telekom will ensure that LTE–network is rolled out across a wide area in 100 additional cities.

Exercise to chapter


Exercise 4.5: LTE vs LTE-Advanced

List of Sources

  1. Gutt, E.: LTE - a new dimension of mobile broadband use. PDF document on the Internet, 2010.
  2. Goldman, D.: AT&T launching 'new' new 4G network. http://money.cnn.com/2011/05/25/technology/att_4g_lte/index.htm PDF–Document on the Internet], 2011
  3. Wannstrom, J.: LTE–Advanced. http://www.3gpp.org/technologies/keywords-acronyms/97-lte-advanced PDF–Document on the Internet, 2011]