Methods and Devices for Configuring User Equipments with Multiple Transmit Antennas

A method in a radio network controller of a wideband code division multiple access, WCDMA, radio system, the radio system comprising a mixture of radio base stations of a first type that are capable of decoding transmissions in a first control channel format in an uplink multi-antenna transmission from a user equipment (UE) and radio base stations of a second type that are not capable of decoding transmissions in said first control channel format in an uplink multi-antenna transmission from the UE, the UE being connected to an active set of cells, the method comprising:

• when a cell belonging to a radio base station of the second type is added into the active set of the UE, configuring uplink transmission of at least one transmit antenna of the UE to use a second control channel format that can be decoded by radio base stations of both the first and second types.

A method in a user equipment (UE) having at least two transmit antennas and being capable of uplink multi-antenna transmission, the UE being connected to an active set of cells, and wherein the active set can comprise a mixture of radio base stations of a first type that are capable of decoding transmissions in a first control channel format in an uplink multi-antenna transmission from the UE and radio base stations of a second type that are not capable of decoding transmissions in said first control channel format in an uplink multi-antenna transmission from the UE, the method comprising:

• receiving at least one control signal, the at least one control signal controlling uplink transmission of at least one of the transmit antennas of the UE to use a second control channel format that can be decoded by both said radio base stations of first and second type.

A radio network controller of a wideband code division multiple access (WCDMA) radio system, the radio system comprising a mixture of radio base stations of a first type that are capable of decoding transmissions in a first control channel format in an uplink multi-antenna transmission from a user equipment (UE) and radio base stations of a second type that are not capable of decoding transmissions in said first control channel format in an uplink multi-antenna transmission from the UE, the UE being connected to an active set of cells, the radio network controller comprising:

• controller circuitry adapted to configuring uplink transmission of at least one transmit antenna of the UE to use a second control channel format that can be decoded by radio base stations of both the first and second types when a cell belonging to a radio base station of the second type is added into the active set of the UE.

A user equipment (UE) having at least two transmit antennas and being capable of uplink multi-antenna transmission, the UE being connectable to an active set of cells, wherein the active set can comprise a mixture of cells associated with radio base stations of a first type that are capable of decoding transmissions in a first control channel format in an uplink multi-antenna transmission from the UE and cells associated with radio base stations of a second type that are not capable of decoding transmissions in said first control channel format in an uplink multi-antenna transmission from the UE, the UE comprising:

• controller circuitry adapted to receive at least one control signal controlling uplink transmission of at least one of the transmit antennas of the UE to use a second control channel format decodable by radio base stations of both the first and second types.