Carrier Aggregation is one of the most important techniques for wireless communication systems.
And it is not very difficult to understand that several pathways or connections torwards a cell are better than a single one - more “things” can pass through.
It is clear that this is directly linked to the availability of roads or resources, and in our case, additional spectrum.
Adding additional spectrum allows reaching much higher rates.
And to better understand this concept, we use an analogy from the physical world, representing the virtual connection of the spectrum as vehicular traffic lanes on a highway.
Imagine the individual vehicles as bits of information, and understand the roads correspond to the available wireless spectrum.
The communication between the user and the cell can be represented by the image of a lane.
But if we have resources, we can add more lanes, we can traffic more vehicles, at the same time!
Carrier Aggregation can be implemented using channels in the same cellular band (intraband) or in multiple bands (interband). Within a band, the added channels can be adjacent (contiguous) or not.
In short, Carrier Aggregation allows you to glue two (or more) connections that exist in completely separate physical space and combine them in such a way that they can be treated as one much larger and much faster connection!
To the effective band width, two added signals are the sum of the band width of all the carriers. For example, if each channel has a bandwidth of 20 MHz, with 5-level carrier aggregation, the effective bandwidth of the resulting connection will be 100 MHz!