Carrier Aggregation is a technology to combine two or more carriers into one data channel to enhance the data capacity. It is possible to combine carriers in the same or different frequency bands.
Using wireless communication to increase the data rate per user, whereby multiple frequency blocks (called component carriers) are assigned to the same user. The maximum possible data rate per user is increased the more frequency blocks are assigned to a user.
It combines multiple carriers to expand the spectrum bandwidth. CA is a new feature of LTE Advanced which helps the users with increased data speeds (both in uplink and downlink). CA technology is implemented in most modern mobile communication systems, like LTE and WiMax
