Radio base station apparatus and communication terminal

A radio base station apparatus comprising:

• a guard interval determining section that determines a guard interval in OFDM using information of delay profile contained in a spread uplink signal;
• an OFDM section that performs OFDM processing on transmission data using the guard interval;
• a spreading section that performs spreading on a known signal for use by a communication terminal apparatus to generate the delay profile;
• and
• a multiplexing section that multiplexes the transmission data subjected to the OFDM processing and the known signal subjected to the spreading.

A base station apparatus comprising:

• a despreading section that performs despreading on a spread uplink signal to output a despread signal;
• a delay profile generating section that generates a delay profile using the despread signal;
• a guard interval determining section that determines a guard interval in OFDM using the delay profile;
• a Doppler frequency measuring section that measures a Doppler frequency using the despread signal;
• a transmission parameter determining section that determines a subcarrier parameter using a measurement result of the Doppler frequency;
• a modulation scheme/coding rate determining section that determines a modulation scheme and a coding rate using OFDM transmission parameters including the guard interval and the subcarrier parameter, the delay profile, the Doppler frequency and downlink received quality contained in the uplink signal;
• and
• an OFDM section that performs OFDM processing on transmission data and a known signal into which the OFDM transmission parameters, the modulation scheme and the coding rate are inserted.

A radio communication method comprising:

• in a radio base station apparatus,
• a despreading step of performing despreading on a spread uplink signal to output a despread signal;
• a delay profile generating step of generating a delay profile using the despread signal;
• a guard interval determining step of determining a guard interval in OFDM using the delay profile;
• a first OFDM processing step of performing OFDM processing on a known signal and transmission data, using OFDM transmission parameters which includes the guard interval and which is inserted into the known signal;
• and
• a transmitting step of transmitting a signal subjected to the OFDM processing to a communication terminal apparatus as a downlink signal, and
• in the communication terminal apparatus,
• a transmission parameter extracting step of extracting the OFDM transmission parameters from the known signal;
• and
• a second OFDM processing step of performing OFDM processing on a received signal using the OFDM transmission parameters.

A radio communication method comprising:

• in a communication terminal apparatus,
• a despreading step of performing despreading on a known signal of a spread downlink signal to output a despread signal;
• a delay profile generating step of generating a delay profile using the despread signal;
• and
• a first transmitting step of performing spreading on information of the delay profile and transmitting the information in an uplink signal to a radio base station apparatus, and
• in the base station apparatus,
• a guard interval determining step of determining a guard interval in OFDM using the information of the delay profile;
• a multiplexing step of performing OFDM processing on transmission data using OFDM transmission parameters including the guard interval, further performing spreading on the known signal including the OFDM transmission parameters, and multiplexing an OFDM signal subjected to the OFDM processing and a CDMA signal subjected to the spreading;
• a second transmitting step of transmitting the multiplexed signal to the communication terminal apparatus as a downlink signal;
• a transmission parameter extracting step of extracting the OFDM transmission parameters from the multiplexed signal of the downlink signal;
• and
• an OFDM processing step of performing OFDM processing on a received signal using the OFDM transmission parameters.

A radio communication method comprising:

• in a base station apparatus,
• a despreading step of performing despreading on a spread uplink signal to output a despread signal;
• a delay profile generating step of generating a delay profile using the despread signal;
• a guard interval determining step of determining a guard interval in OFDM using the delay profile;
• a Doppler frequency measuring step of measuring a Doppler frequency using the despread signal;
• a transmission parameter determining step of determining a subcarrier parameter using a measurement result of the Doppler frequency;
• a modulation scheme/coding rate determining step of determining a modulation scheme and coding rate using OFDM transmission parameters including the guard interval and the subcarrier parameter, the delay profile, the Doppler frequency and downlink received quality contained in the uplink signal;
• a first OFDM processing step of performing OFDM processing on transmission data and a known signal into which the OFDM transmission parameters, the modulation scheme and the coding rate are inserted;
• and
• a transmitting step of transmitting a signal subjected to the OFDM processing to a communication terminal apparatus as a downlink signal, and
• in the communication terminal apparatus,
• a transmission parameter extracting step of extracting the OFDM transmission parameters from the known signal;
• a modulation scheme/coding rate extracting step of extracting the modulation scheme and the coding rate from the known signal;
• a second OFDM processing step of performing OFDM processing on a received signal using the OFDM transmission parameters;
• a demodulation step of demodulating a received signal based on the modulation scheme;
• a decoding step of decoding the demodulated signal based on the coding rate;
• and
• a received quality measuring step of measuring received quality using the received signal.