In wireless communication, carrier aggregation is a technique used to increase the data rate per user, whereby multiple frequency blocks (called component carriers) are assigned to the same user.[1] 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[2]: p.42 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.[3]