Abstract: A method for controlling the aggregate interference of a secondary system (10) in a cognitive radio network comprises the steps of computing the power density (Pd,i), footprint (Afoot,i) and service area (Ai) for each of the cells (100) of the secondary system (10) that satisfy the interference constraint at a given point (P) in a primary system (50); summing the power densities (Pd,i) for all cells (100) for the point (P); and using the sum of the power density at the point (P) to decide which power level a new secondary system (10) user is allowed to use in a given cell (100). A system for performing such a method is also disclosed.

Abstract: A method for controlling the aggregate interference of a secondary system (10) in a cognitive radio network comprises the steps of computing the power density (Pd,i), footprint (Afoot,i) and service area (Ai) for each of the cells (100) of the secondary system (10) that satisfy the interference constraint at a given point (P) in a primary system (50); summing the power densities (Pd,i) for all cells (100) for the point (P); and using the sum of the power density at the point (P) to decide which power level a new secondary system (10) user is allowed to use in a given cell (100). A system for performing such a method is also disclosed.

Abstract: In connection with the determination the transmit power of a beginning transmission there is also determined, in the method according to the invention, suitable output powers for other transmissions, so that the entity formed by all controlled transmissions is as close to the optimum as possible already at the beginning of a new frame. The method according to the invention takes into consideration the effect of a beginning transmission on other transmissions. The method according to the invention further takes into consideration changes in the conditions during the previous frame by including the control history of the fast power control as initial information of the calculation made during the re-determination of the output powers, for instance as a suitable statistical quantity of the transmission history of each transmission, for instance as an average over a certain period.