Base station apparatus, terminal apparatus, and communication method

A terminal apparatus for communicating with a base station apparatus, the terminal apparatus comprising:

• a radio signal receiver that receives, from the base station apparatus, a first demodulation reference signal and a second demodulation reference signal that are reference signals used to demodulate a data signal, the data signal, and control information;
• and
• a radio signal detector that demodulates the data signal by using the first demodulation reference signal and the second demodulation reference signal, wherein
• the control information includes parameters regarding the first demodulation reference signal and parameters regarding the second demodulation reference signal,
• the parameters regarding the first demodulation reference signal include information for deriving an antenna port index,
• the parameters regarding the second demodulation reference signal include information for deriving an antenna port index, and a time domain density or a frequency domain density with which demodulation reference signals are mapped into a minislot,
• the first demodulation reference signal is mapped before the second demodulation reference signal in the minislot, and the first demodulation reference signal is mapped in a fixed mapping pattern for each carrier frequency range, and wherein
• a time duration length of the minislot is one of 2, 4, or 7 OFDM symbols, and a first mapping pattern of the first demodulation reference signal and a second mapping pattern of the second demodulation reference signal are different.

A communication method in a base station apparatus for communicating with a terminal apparatus, the communication method comprising:

• a downlink reference signal generation step of generating a first demodulation reference signal and a second demodulation reference signal that are reference signals used to demodulate a data signal;
• and
• a radio transmission step of transmitting the first demodulation reference signal, the second demodulation reference signal, and control information to the terminal apparatus, wherein
• the control information includes parameters regarding the first demodulation reference signal and parameters regarding the second demodulation reference signal,
• the parameters regarding the first demodulation reference signal include information for deriving an antenna port index,
• the parameters regarding the second demodulation reference signal include information for deriving an antenna port index, and a time domain density or a frequency domain density with which demodulation reference signals are mapped into a minislot,
• the first demodulation reference signal is mapped before the second demodulation reference signal in the minislot, and the first demodulation reference signal is mapped in a fixed mapping pattern for each carrier frequency range, and wherein
• a time duration length of the minislot is one of 2, 4, or 7 OFDM symbols, and a first mapping pattern of the first demodulation reference signal and a second mapping pattern of the second demodulation reference signal are different.

A communication method in a terminal apparatus for communicating with a base station apparatus, the communication method comprising:

• a radio receiving step of receiving, from the base station, a first demodulation reference signal and a second demodulation reference signal that are reference signals used to demodulate a data signal, the data signal, and control information;
• and
• a signal detection step of demodulating the data signal by using the first demodulation reference signal and the second demodulation reference signal, wherein
• the control information includes parameters regarding the first demodulation reference signal and parameters regarding the second demodulation reference signal,
• the parameters regarding the first demodulation reference signal include information for deriving an antenna port index,
• the parameters regarding the second demodulation reference signal include information for deriving an antenna port index, and a time domain density or a frequency domain density with which demodulation reference signals are mapped into a minislot,
• the first demodulation reference signal is mapped before the second demodulation reference signal in the minislot, and the first demodulation reference signal is mapped in a fixed mapping pattern for each carrier frequency range, and wherein
• a time duration length of the minislot is one of 2, 4, or 7 OFDM symbols, and a first mapping pattern of the first demodulation reference signal and a second mapping pattern of the second demodulation reference signal are different.