Methods and devices for configuring user equipments with multiple transmit antennas
In deployments where there is a mixture of new Node Bs capable of uplink multi-antenna transmission and legacy Node Bs not capable of uplink multi-antenna transmission some embodiments described herein enable a network node (e.g. a radio network controller, RNC) to configure an uplink control channel (e.g. dedicated physical control channel, DPCCH) to be decodable by both the new and the legacy Node 8 s when the UE operates in uplink multi-antenna transmission.
1. 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:
in response to an addition of a cell belonging to a radio base station of the second type to 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,
wherein the uplink multi-antenna transmission is uplink (UL) Multiple-Input Multiple-Output (MIMO) or uplink Beam Forming Transmit Diversity (BFTD), and
wherein the radio network controller configures a radio base station of the second type to not transmit UL Transmission Power Control (TPC) commands to a UE operating in UL MIMO or UL BLTD mode.
2. The method of claim 1 , wherein the radio network controller notifies the UE when a radio link is set up about what cell or cells in the active set of the UE belong to a radio base station of the second type.
3. 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 comprising a processor and associated memory, wherein the controller circuitry is adapted to configure 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, in response to an addition of a cell belonging to a radio base station of the second type to the active set of the UE,
wherein the uplink multi-antenna transmission is uplink (UL) Multiple-Input Multiple-Output (MIMO) or uplink Beam Forming Transmit Diversity (BFTD), and
wherein the controller circuitry is adapted to configure a radio base station of the second type to not transmit UL Transmission Power Control (TPC) commands to a UE operating in UL MIMO or UL BFTD mode.
4. The radio network controller of claim 3 , wherein the controller circuitry is adapted to notify the UE when a radio link is set up about what cell or cells in the active set of the UE belong to a radio base station of the second type.
5. The radio network controller of claim 3 , wherein the control channel is a dedicated physical control channel.