Carrier aggregation is a technique used in 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. The sum data rate of a cell is increased as well because of a better resource utilization. In addition load balancing is possible with carrier aggregation. Channel selection schemes for CA systems taking into account the optimal values for the training length and power, the number of the probed sub-channels and the feedback threshold such that the sum rate is also important for optimal achievable capacity.
Types of carrier aggregation
There is no difference between these three cases from a baseband perspective. However, the complexity from an RF point of view is increased in the case inter-band carrier aggregation.