LTE (Long Term Evolution) is an evolution of GSM / EDGE, CDMA2000, TD-SCDMA and UMTS mobile telephony standards.
The LTE standard, defined by the 3GPP consortium [1], was initially considered as a third generation standard "3.9G" (because close to 4G), specified in the framework of IMT-2000 technologies, because in the "Versions 8 and 9" of the standard, it did not meet all the technical specifications imposed for 4G standards by the International Telecommunication Union (ITU). The LTE standard is not fixed, the 3GPP consortium is constantly evolving (usually a new version every 12 to 18 months [1]).
In October 2010, the ITU recognized the LTE-Advanced technology (LTE evolution defined by 3GPP from its release 10) as a full-fledged 4G technology [2], [3]; then, in December 2010, it granted the LTE and WiMAX standards defined before the "IMT-Advanced" specifications and which did not fully meet its prerequisites, the commercial possibility of being considered "4G" technologies, as a result of a significant improvement in performance compared to those of the first 3G systems: UMTS and CDMA2000 [4].
LTE mobile networks are marketed under the name "4G" by operators in many countries, for example: Proximus, Base, VOO Mobile and Orange in Belgium, Swisscom and Sunrise in Switzerland, Verizon and AT & T in the United States, Videotron, Rogers and Fido Solutions in Canada, Orange, Bouygues Telecom, SFR and Free Mobile in France, Algeria Telecom in Algeria, Maroc Telecom, Orange and Inwi in Morocco ...
LTE uses wireless frequency bands ranging in width from 1.4 MHz to 20 MHz in a frequency range of 450 MHz to 3.8 GHz depending on the country. It achieves (for a bandwidth of 20 MHz) a theoretical bit rate of 300 Mbit / s in "downlink" (downlink, to the mobile). The "true 4G [5]", called LTE Advanced [1] will provide a downlink rate of up to 1 Gbps; this rate will require the use of aggregated 2 × 100 MHz wide frequency bands which are defined in LTE Advanced [1] versions 10-13 (3GPP releases 10, 11, 12 and 13).