Patent ID: 8462609

Claim:
Method for carrier aggregation of at least two Orthogonal Frequency Division Multiplexing (OFDM) carriers in a radio communication system, each of said at least two OFDM carriers comprising subcarriers being spaced in accordance with a subcarrier spacing of said radio communication system, respectively, the method comprising: allocating frequencies in a spectrum, such that the subcarriers of said at least two OFDM carriers are located separated from each other by a multiple of said subcarrier spacing, and synchronizing transmission on said at least two OFDM carriers in time, wherein at least one of said at least two OFDM carriers is an extended legacy carrier being compatible with a legacy radio communication system, said extended legacy carrier being a legacy carrier of said legacy radio communication system, to which legacy carrier at least one additional subcarrier has been added; wherein an aggregated carrier resulting from the carrier aggregation is used for downlink transmission in the radio communication system; wherein said at least two OFDM carriers are transmitted from at least two different transmitters; wherein, in a handover situation, said at least two OFDM carriers include at least one OFDM carrier being transmitted from a serving cell transmitter and at least one OFDM carrier being transmitted from a target cell transmitter.