LTE stands for Long Term evolution and is developed by 3GPP to provide data intensive and delay sensitive applications/services. Existing 3G network was unable to handle few services and even was not capable to handle future services. Some people says LTE is 4G network but ITU has defined wireless 4G network which provides high throughput, higher spectrum efficiency, ICIC etc features over the existing LTE network.
LTE advanced uses more spectrum as compare to LTE technology and provides high throughput by using multiple input and multiple output, in short MIMO. LTE advanced provides carrier aggregation which is one of the most and wonderful concept which differentiates LTE advanced from LTE .