Transmission method and transmission apparatus

A transmission apparatus having multiple antennas comprising:

• a transmission and modulation scheme selection processor configured to select (i) a transmission scheme for transmitting a plurality of transmission signals from among a plurality of transmission schemes according to a number of different data streams used for a transmission, and (ii) a modulation scheme from among a plurality of modulation schemes according to the number of different data streams used for a transmission, where different data streams contain different data symbols;
• a modulator configured to modulate the plurality of transmission signals using the selected modulation scheme and to output a plurality of modulated transmission signals;
• and
• a transmitter configured to transmit the plurality of modulated transmission signals using the number of different data streams used for the transmission among the multiple antennas,
• wherein the transmission and modulation scheme selector processor is configured to:
• select, when a first number of different data streams is used for the transmission, a modulating scheme in which a maximum value of a number of modulated M-ary index of the selected modulation scheme is smaller than a maximum value of a number of modulated M-ary index of the modulation scheme selected when a second number of multiple different data streams less than the first number of multiple different data streams is used for the transmission, and
• select, when the second number of multiple different data streams is used for the transmission, a modulating scheme having a same maximum value of a number of modulated M-ary index for every selected transmission scheme.