| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio base station and a radio communication method which can transmit a sounding reference signal (SRS) at a timing when the directivity of an antenna can be adequately set. <P>SOLUTION: A user data resource determination unit 7 determines any plurality of sub-carriers in any of downlink subframes as a first resource to transmit downlink user data to a radio terminal. A sounding resource determination unit 8 determines a part of the uplink part in a switch-over subframe closest and prior to the determined downlink subframe as a second resource for the radio terminal to transmit a sounding reference signal, and notifies the radio terminal of the determined second resource. A transmission path state estimation unit 9 estimates the state of a transmission path with the radio terminal based on the sounding reference signal from the radio terminal. A transmission unit 4 forms the directivity of a plurality of antennas 2 and 3 based on the estimated state of the transmission path to transmit downlink user data. <P>COPYRIGHT: (C)2012,JPO&INPIT |
