Patent ID: 8095169

Claim:
A radio communication apparatus for transmitting a radio signal to multiple users via multiple transmit antenna groups at appropriate transmit power levels, each of the transmit antenna groups including one or more transmit antennas, the transmit antenna groups having respective transmit power constraints, the apparatus comprising: a precoding unit configured to precode multiple streams; a splitting unit configured to split the precoded streams into two or more stream sets each including one or more streams; a sub power optimization unit configured to execute iterative transmit power optimization algorithms on the split stream sets to determine respective transmit power levels for the individual stream sets; a power optimization unit configured to execute an iterative transmit power optimization algorithm by using the determined transmit power levels as initial values for the iterative transmit power optimization algorithm to determine respective transmit power levels for the individual streams; and a transmission unit configured to transmit radio signals from individual transmit antennas at the determined transmit power levels.