The LTE technology was first proposed by NTT DoCoMo of Japan in 2004, and studies on the new standard officially commenced in 2005. The LTE standard was finalized in December 2008 and the LTE service was first publicly 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 in 2011, with the starting of first commercially available LTE smartphone Samsung Galaxy Indulge offered by MetroPCS.
Evolved UMTS Terrestrial Radio Access Network (E-UTRA) is the air interface of LTE upgrade path for mobile networks. It is a radio access network standard to replace the UMTS, HSDPA and HSUPA technologies specified in 3GPP releases 5 and beyond. The E-UTRA has provide several features that enhances the mobile networks.
1) Peak download rates of 300 Mbit/s.
2) Peak upload rates of 75.4 Mbit/s for a 20MHz channel in the LTE standard.
3) Improved support for mobility, and also support for terminals that moving at up to 350km/h or 500km/h depending on the frequency band.
4) Support for both FDD and TDD communication systems as well as half duplex FDD with the same radio access technology
5) support for all frequency bands currently used by IMT system ( International mobile telecommunication).
6) Low data transfer latency, and also lower latency for handover and connection setup time than previous radio access technologies.
7) Increment of spectrum flexibility with 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz and 20MHz wide cell are standardized.
8) Simplified architecture
9) Support for inter-operation with other systems such as GSM and UMTS
10) Support improved spectral efficiency at 2-5 times more than in 3GPP (HSPA)
11) Support of cell sizes from radius of 10m up to over 100km.
12) support at least 200 active data clients in every 5MHz cell.
However, LTE standard is only supports packet switching with its all-IP network. For voice calls GSM,UMTS and CDMA2000 which are in circuit switched, the carriers have to re-engineer their voice call network. There are three different approaches had sprang up, there are CSFB (circuit Switched Fallback), SVLTE (Simultaneous Voice and LTE) and also VoLTE (Voice over LTE).
In CSFB, LTE just provides data services. When a voice call is to be initiated or received, it will fall bac to the CS domain, thus the operators just need to upgrade the MSC therefore provide services quickly. However it will caused longer call setup delay.
In SVLTE, the handset work simultaneously in the LTE and circuit switched modes, which means the handset is providing services and also voice service at the same time, but the phone can become expensive with high power consumption since it providing both services.
In VoLTE, the operators provide over-the-top content services which use applications such as Skype to provde LTE voice service. But the approach still not receive too much support in the telecom industry.
In VoLTE, the operators provide over-the-top content services which use applications such as Skype to provde LTE voice service. But the approach still not receive too much support in the telecom industry.
The above picture shows that LTE provides path for all 3GPP and non-3GPP technologies to upgrade to LTE.
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