MIMO System

A method in a radio base station, said radio base station configured to participate in high speed downlink packet access (HSDPA) multiple input multiple output (MIMO) operation wherein data is communicated to a user equipment (UE) via the radio base station, the method comprising:

• receiving, from a radio network controller, medium access control-d (MAC-d) protocol data units (PDUs);
• receiving, from the UE, at least two channel quality indicator (CQI) values and a rank information (RI) value;
• determining, in case the RI value is at least three, a transport format and resource combination (TFRC) for transmission of a first medium access control-enhanced high speed (MAC-ehs) PDU, a second MAC-ehs PDU and at least one additional MAC-ehs PDU to the UE during a transmission time interval (TTI) such that the TFRC specifies a size of the at least one additional MAC-ehs PDU to be identical to a size of any of the first MAC-ehs PDU and the second MAC-ehs PDU;
• and
• transmitting the MAC-d PDUs in MAC-ehs PDUs according to the determined TFRC to the UE in a high speed downlink shared channel (HS-DSCH).

A radio base station, said radio base station configured to participate in high speed downlink packet access (HSDPA) multiple input multiple output (MIMO) operation wherein data is communicated to a user equipment (UE) via the radio base station, the radio base station comprising digital data communication and processing circuitry adapted to:

• receive, from a radio network controller, medium access control-d (MAC-d) protocol data units (PDUs);
• receive, from the UE, at least two channel quality indicator (CQI) values and a rank information (RI) value;
• determine, in case the RI value is at least three, a transport format and resource combination (TFRC) for transmission of a first medium access control-enhanced high speed (MAC-ehs) PDU, a second MAC-ehs PDU and at least one additional MAC-ehs PDU to the UE during a transmission time interval (TTI) such that the TFRC specifies a size of the at least one additional MAC-ehs PDU to be identical to a size of any of the first MAC-ehs PDU and the second MAC-ehs PDU;
• and
• transmit the MAC-d PDUs in MAC-ehs PDUs according to the determined TFRC to the UE in a high speed downlink shared channel (HS-DSCH).

A computer program product stored in a computer readable medium and comprising software instructions that, when executed by a processor in a radio base station that is configured to participate in high speed downlink packet access (HSDPA) multiple input multiple output (MIMO) operation wherein data is communicated to a user equipment (UE) via the radio base station, configure the processor to:

• receive, from a radio network controller, medium access control-d (MAC-d) protocol data units (PDUs);
• receive, from the UE, at least two channel quality indicator (CQI) values and a rank information (RI) value;
• determine, in case the RI value is at least three, a transport format and resource combination (TFRC) for transmission of a first medium access control-enhanced high speed (MAC-ehs) PDU, a second MAC-ehs PDU and at least one additional MAC-ehs PDU to the UE during a transmission time interval (TTI) such that the TFRC specifies a size of the at least one additional MAC-ehs PDU to be identical to a size of any of the first MAC-ehs PDU and the second MAC-ehs PDU;
• and
• transmit the MAC-d PDUs in MAC-ehs PDUs according to the determined TFRC to the UE in a high speed downlink shared channel (HS-DSCH).