Radio base station apparatus, mobile station apparatus and radio communication method

A radio base station apparatus comprising:

• a plurality of transmission antennas;
• an orthogonalizing section configured to orthogonalize downlink reference signals allocated to a plurality of radio resources of same frequency and different time regions, between layers by using orthogonal codes;
• and
• a transmission section configured to transmit a signal that is multiplexed with the downlink reference signals and transmission data, from the plurality of transmission antennas in multiple layers,
• wherein sequence information of the downlink reference signals and information of the orthogonal codes are signaled to a mobile station apparatus.

A mobile station apparatus comprising:

• a reception section configured to receive a signal that is multiplexed with downlink reference signals and transmission data, the downlink reference signals being allocated to a plurality of radio resources of same frequency and different time regions and being orthogonalized between layers using orthogonal codes;
• and
• a data demodulation section configured to demodulate the transmission data by using the downlink reference signals,
• wherein sequence information of the downlink reference signals and information of the orthogonal codes are signaled from a radio base station apparatus.

A radio communication method comprising the steps of:

• in a radio base station apparatus, orthogonalizing downlink reference signals allocated to a plurality of radio resources of same frequency and different time regions, between layers by using orthogonal codes;
• transmitting a signal that is multiplexed with the downlink reference signals and transmission data, from a plurality of transmission antennas in multiple layers;
• in a mobile station apparatus,
• receiving the signal;
• and
• demodulating the transmission data by using the downlink reference signals of the signal,
• wherein sequence information of the downlink reference signals and information of the orthogonal codes are signaled from the radio base station apparatus to the mobile station apparatus.

A radio communication system comprising:

• a radio base station apparatus comprising:
• an orthogonalizing section configured to orthogonalize downlink reference signals allocated to a plurality of radio resources of same frequency and different time regions, between layers by using orthogonal codes;
• and
• a transmission section configured to transmit a signal that is multiplexed with the downlink reference signals and
• transmission data, from a plurality of transmission antennas in multiple layers;
• and
• a mobile station apparatus comprising:
• a reception section configured to receive the signal;
• and
• a data demodulation section configured to demodulate the transmission data by using the downlink reference signals of the signal,
• wherein sequence information of the downlink reference signals and information of the orthogonal codes are signaled from the radio base station apparatus to the mobile station apparatus.