How does 4G LTE differ than 4G?

In fact LTE can not be really considered as a4G technology.
We can classify it as3.9G, seeing that4G standards must respond to IMT-Advanced requirements.
The LTE-A (A stands for advanced) corresponds to LTE release10 and it is the LTE enhacment that can be classified as4G.
Kind regards

4G requrment is to reach the download speed up to 1 gega to walking users , and to reach the download speed up to 100 mega to fast users ( like user travel in train ) , so LTE it's reach up to 100 mega also 300 mega if used MIMO , then the LTE it is pre-4G it is 3.5G , but LTE-ADVANCE it is only that account 4G .

There are two4G systems are commercially deployed: the Mobile WiMAX standard (at first in South Korea in2006), and the first-release Long Term Evolution (LTE) standard (in Oslo, Norway and Stockholm, Sweden since2009).
Both LTE and4G are standard names for the Telecom speeds and facilities.
LTE is a brief of (LONG TERM EVOLUTION), Known also as4G LTE LTE is a standard for wireless data communications technology and an evolution of the GSM/UMTS standards.
The goal of LTE was to increase the capacity and speed of wireless data networks using new DSP (digital signal processing) techniques and modulations that were developed around the turn of the millennium.
A further goal was the redesign and simplification of the network architecture to an IP-based system with significantly reduced transfer latency compared to the3G architecture.
The LTE wireless interface is incompatible with2G and3G networks, so that it must be operated on a separate wireless spectrum.
I hope that the idea is clear now! Best Regards

the LTE  SYSTEM CAN NOT REALLY4G SYSTEM BECAUSE IS NOT MATCH WITH THE STANDDERS CRIETRIA Which were developed by International Telecommunication Union (ITU) TO REACH TO4G SYSTEMS .
BUT THE LTE ADVANECE IS REALLY4G BECAUSE IS REACHED TO ONE OF STANDARDS OF4G WHICH IS THE DOWNLOAD IS REACH TO1GB .THE LTE IS DIFFER FROM ANOTHER BECAUS THE STRUCTURE IS compatible WETH2G GSM &EDGE AND3G UMTS WCDMA NETWORKS It is an extension of the this networks and When we want to apply LTE system we do not need Previous to the cancellation of the structure in the second generation or third generation, but make adjustments and develop them in order to give us the system services  OF LTE.

4G by itself is a set of requirements, for a technology to be considered a4G one it must meet these requirements, neither LTE nor mobile WiMAX(802.16e) meet the4G requirements. However, LTE-advanced and802.16m do meet these requirements and therefore they are considered a4G technology.