User terminal, wireless base station, and wireless communication method

A base station, comprising:

• a receiver coupled to a processor that:
• selects different terminal transmission patterns for respective terminals from a plurality of terminal transmission patterns, and
• maps demodulation reference signals orthogonal to each other between the terminal transmission patterns to resource elements defined for the respective terminal transmission patterns;
• and
• a transmitter that transmits a downlink signal including the demodulation reference signal,
• wherein:
• the plurality of terminal transmission patterns are different from each other in arrangement of at least a part of the resource elements to which the demodulation reference signal is mapped, and
• the demodulation reference signals mapped to a same resource element between the terminal transmission patterns are orthogonal to each other by using c relic shift or an orthogonal sequence.

A communication method, comprising:

• receiving a downlink signal including a demodulation reference signal;
• separating the demodulation reference signal from the downlink signal;
• and
• calculating a channel estimation value with use of the demodulation reference signal, wherein:
• the demodulation reference signal is mapped to resource elements defined for a terminal transmission pattern,
• the terminal transmission pattern is selected to be different between terminals, from a plurality of terminal transmission patterns,
• the demodulation reference signals mapped to the resource elements defined for the respective terminal transmission patterns are orthogonal to each other between the terminal transmission patterns,
• the plurality of terminal transmission patterns are different from each other in arrangement of at least a part of the resource elements to which the demodulation reference signal is mapped, and
• the demodulation reference signals mapped to a same resource element between the terminal transmission patterns are orthogonal to each other by using cyclic shift or an orthogonal sequence.