This work proposes a formulation to calculate the transmitter power needed to cover cells of different sizes whilst maintaining the signal to interference-plus-noise ratio (SINR) constant, and near the maximum, for two long-term evolution-advanced (LTE-A) systems with an integrated common radio resource management (iCRRM) entity, in the context of spectrum aggregation (SA). The iCRRM entity is able to switch users between two LTE-A systems operating on non-contiguous frequency bands, 800 MHz and 2 GHz. The proposed formulation is based on the computation of the average received power and average co-channel interference in cellular topologies with frequency reuse pattern K = 3 whilst keeping the presence of coverage holes insignificant. The objective of applying this formulation in the dimensioning process is to save power for shorter coverage distances. We apply the COST-231 Hata path loss model and we corroborate the effect of the orthogonality factor in LTE's SINR.