Patent ID: 7069054

Claim:
A radio apparatus ( 2000 ) varying antenna directivity in real time, and transmitting and receiving signals to and from a plurality of terminals, comprising: a plurality of antennas (# 1 to # 4 ) arranged in a discrete manner; a first reception circuit (SR 1 ) receiving signals from said plurality of antennas, and separating a signal from a first terminal among the signals from said plurality of terminals; and a second reception circuit (SR 2 ) receiving signals from said plurality of antennas, and separating a signal from a second terminal among the signals from said plurality of terminals; wherein said first reception circuit i) separates the signal from said first terminal, based on the signals from said plurality of antennas in receiving a reception signal, ii) generates a first replica signal based on the separated signal from said first terminal, and calculates a first reception correlation vector with respect to the signal from said first terminal, in accordance with said first replica signal and the signals from said plurality of antennas in receiving said reception signal, iii) generates a second replica signal corresponding to the signal from said second terminal with the signals from said plurality of antennas, based on separation control information for separating the signal from said second terminal in said second reception circuit in receiving said reception signal, and iv) estimates a reception response vector with respect to the signal from said first terminal, based on a second reception correlation vector with respect to the signal from said second terminal, said first reception correlation vector, and a correlation matrix calculated from said first and second replica signals.