A method in a recipient, for providing HARQ feedback for data received in a downlink using carrier aggregation of a downlink Frequency-Division Duplexing, FDD, carrier and at least one Time-Division Duplexing, TDD, carrier, in an uplink control channel resource in an uplink FDD carrier, said method comprising: receiving data on at least one of: downlink subframes on a downlink data channel of the downlink FDD carrier and a downlink subframe on a downlink data channel of the TDD carrier; determining whether the data has been correctly received, or not; selecting a sequence and a modulation symbol, or selecting a modulation symbol, to form a HARQ message in an uplink control channel subframe of the uplink FDD carrier, corresponding to an acknowledgement, ACK, for data determined to have been correctly received, a non-acknowledgement, NACK, for data determined to not having been correctly received and/ or a Discontinuous Transmission, DTX, for data not having been received; and transmitting HARQ feedback related to the received data, on a scheduling request resource in the uplink control channel subframe of the uplink FDD carrier assigned to the recipient, comprising the selected sequence and modulation symbol, or the selected modulation symbol in the HARQ message; wherein spatial bundling is performed in uplink control channel subframes which are assigned for HARQ feedback of both the downlink FDD carrier and TDD carrier (200, 250); and spatial bundling is not performed in uplink control channel subframes which are assigned for HARQ feedback of the downlink FDD carrier, and wherein the HARQ feedback for the downlink subframe (210, 360) n is transmitted on the uplink control channel subframe of the uplink FDD carrier number n + 4. receiving data on at least one of: downlink subframes on a downlink data channel of the downlink FDD carrier and a downlink subframe on a downlink data channel of the TDD carrier; determining whether the data has been correctly received, or not; selecting a sequence and a modulation symbol, or selecting a modulation symbol, to form a HARQ message in an uplink control channel subframe of the uplink FDD carrier, corresponding to an acknowledgement, ACK, for data determined to have been correctly received, a non-acknowledgement, NACK, for data determined to not having been correctly received and/ or a Discontinuous Transmission, DTX, for data not having been received; and transmitting HARQ feedback related to the received data, on a scheduling request resource in the uplink control channel subframe of the uplink FDD carrier assigned to the recipient, comprising the selected sequence and modulation symbol, or the selected modulation symbol in the HARQ message; wherein spatial bundling is performed in uplink control channel subframes which are assigned for HARQ feedback of both the downlink FDD carrier and TDD carrier (200, 250); and spatial bundling is not performed in uplink control channel subframes which are assigned for HARQ feedback of the downlink FDD carrier, and wherein the HARQ feedback for the downlink subframe (210, 360) n is transmitted on the uplink control channel subframe of the uplink FDD carrier number n + 4.