The Acronym LTE stands for term evolution and is generally publishes as 4G LTE. Although LTE is popularly considered as 4G, this technology is only one of this group, however, it is the most common when we talk about the latest generation of mobile internet.
The LTE is evolution of the GSM/UMTS standards, something with which we are a little more related and its purpose is to increase the capacity and speed of wireless data networks by using a new digital signal processing (DSP).
Given the above , the LTE is a big change with respect to 3G but for not meeting the standards of 4G is better defined as 3.9G, since it is neither 3G nor 4G, but is close to the 4G. In order to combat this weakness, 3GPP launched the new specification know as LTE-Advanced.