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LTE Telecommunications

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What is LTE?

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LTE, also known as Long Term Evolution (LTE), was introduced by 3GPP to improve the mobile telephony standard and address the needs and demands of future networks as they evolve and expand.

What is the difference between GPRS, EDGE, 3G and 4G?

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  • GPRS: Service on a 2G network, offering basic data up to 56 kbps (compared to dial-up speed).
  • EDGE: This is a 2.5G technology, and offers higher data transfer rates compared to GPRS (2G). 2G can reach speeds of up to 144 kbps.
  • 3G: This technology provides higher data rates compared to its predecessor 2G and 2.5 G networks (EDGE and GPRS). 3G offers speeds of up to 21 Mbps.
  • 4G: This term is based on LTE technologies and is the latest generation in mobile data transfer. It is the most advanced technology available, and can reach speeds of up to 100 Mbps.

The principles of mobile connectivity

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Although the first prototypes date from much earlier (we only have to look at the fact that in 1973 Martin Cooper made what is considered the first mobile call (ES), we can say that the beginning of massification comes from the 1980s, when the first mobile telephony networks began to be operational.

As is often the case, at the beginning there was no standard, so the first generation telephony (1G) used to cover only the country where it had been developed, as it was incompatible with the networks of other countries. In this generation, the technology was all analog, except for the signaling (geopositioning between satellite and telephone), which was digital (yes, geopositioning already existed at that time).

The first standardization came in this case from Europe, and is called GSM. It currently coexists with other more current ones (as we saw in the article Types of Mobile and Tablet Data networks), and at the time it competed for the position with other alternatives, such as D-AMPS or IS-95.

It is the so-called 2G (or even E for EDGE or EGPRS), which meant a before and after for mobile telephony, but whose main Achilles heel was the data transfer speed (since at the time it was designed for voice and SMS communication).

In view of its shortcomings, in 1998 the International Telecommunication Union formed the IMT-2000 committee, whose mission was to set the necessary standards for the next third generation technology to be considered as such, and in this case, the need to include a minimum data traffic of 2Mbps was contemplated.

Again, there were several alternatives, among which UMTS (the H that appears on our handsets) was finally imposed and is now considered the 3G standard.

The leap to 4G or LTE

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Almost a decade of development of 3G technology (with its HSUPA upgrade, or H+ so that we understand each other), and in 2008 the ITU again formed a new committee, this time called IMT-Advanced, whose mission is the same as ten years ago, but adapted to our days: substantial increase in data transmission speed for complex services and applications (100Mbts).

If you have been following this blog for a long time, you may have read that post I wrote about the 300 million that Spain had to pay to upgrade its networks for the then future 4G, and it is that our beloved country at the time bet on one of the alternatives (DVB-T), looking the other way when the 3GPP organization (which is the creator of GSM and UMTS) presented LTE.

Among all the proposals, once again the 3GPP proposal obtained the 4G standardization, called LTE (Long Term Evolution), which has ended up sweeping the competition (including the WiMAX proposal, which a priori offered more speed).

LTE technology started to be worked on in 2005, and was released at the end of 2009. I mentioned earlier that IMT-Advanced was created in 2008, so by the time LTE was operational, there was still no final release from IMT-Advanced, and of course, when it finally came out, they realized that LTE was not compliant.

Spectrum flexibility

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This is one of the key features. The existence of different regulatory frameworks depending on the geographical area of deployment, as well as the coexistence with other operators or other services and systems, require flexibility in the bandwidth used within the deployment band. Ideally, any bandwidth can be used within this band (in steps of 180 kHz corresponding to the bandwidth of a PRB). In LTE, nominal possible bandwidths of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz are defined.

Protocols

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LTE is composed of different protocols and they are the following:

  • OFDMA:Among the various multiple access techniques known to date, orthogonal frequency division multiple access (OFDMA) is one of the most favored for use in broadband transmission systems. It has been designed to be able to overcome the interference that occurs between the transmitter and receiver and efficiently use the frequency spectrum.
  • TDMA: stands for Time-Division Multiple Access, just like FDMA, or Frequency-Division Multiple Access, TDMA is a technology that allows multiple conversations sharing the same radio channel.
  • RLC: performs PDCP PDU segmentation / concatenation during RLC PDU construction. On the receive side, the RLC protocol performs RLC PDU reassembly to reconstruct the PDCP PDU.
  • PDCP: supports efficient transport of IP packets over the radio link. It performs header compression, access layer (AS), security (encryption and integrity protection) and packet reordering/ retransmission during handover.
  • RRC: can allow the WLAN and WWAN user plane to be coupled at or above the MAC layer, and can leverage the existing WWAN carrier aggregation framework.
  • GTP:(GPRS Tunneling Protocol) is a group of IP-based connection protocols used in GSM, UMTS and LTE networks.



Conclusions

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  • By: Francisco Javier Nuñez G: LTE is a telephony standard for higher speed in mobile communications, as well as this is an evolution of its predecessor, the 3G network transmitted from 1 to 4 Mbps and with LTE or 4G transmits at 300 Mbps and this brought several benefits such as greater speed of transmission of multimedia items, the creation of messaging app with higher performance, etc..
  • By: Maria Fernanda Juarez Gallegoz: In conclusion, thanks to this work we were able to investigate and know the meaning of some things that we see in the classes and review them such as modulations, multiplexing, radioelectric space, the protocols that are usedIt also helps us create a wiki.
  • By: Elias Jacob Ayala Perez: LTE represents a broadband mobile communications technology that has significantly transformed the way we access and share data on mobile devices. By introducing faster connection speeds, higher spectral efficiency and lower latency, LTE has enabled smoother user experiences and increased network capacity to meet the growing demand for mobile services.


References

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