Patent ID: 7453854

Claim:
A signal transmission method for a radio base station in a communication system for controlling transmission of a data signal to each mobile terminal from said radio base station in accordance with a condition of said mobile terminal to receive a pilot signal transmitted from said radio base station to said mobile terminal, wherein based on a control signal received from said mobile terminal, at least an appropriate one of a plurality of signal multiplexing schemes is selected, and transmission signals to each said mobile terminal are multiplexed by said selected signal multiplexing scheme, wherein each of said transmission signal includes a dedicated pilot signal and a data signal transmitted to said mobile terminal, wherein the plurality of signal multiplexing schemes includes space division multiplexing, time division multiplexing, and code division multiplexing, and wherein the space division multiplexing is higher in priority than the time division multiplexing or the code division multiplexing, wherein said selected signal multiplexing scheme includes at least the space division multiplexing, said selected signal multiplexing scheme being selected based on selected one of a direction of each of said plurality of said mobile terminals with respect to said base station and a spatial correlation between said mobile terminals, and wherein said selected signal multiplexing scheme includes the time division multiplexing, and said signal transmission method comprises the steps of: determining a relation between the directions of said plurality of said mobile terminals; determining separability of the transmission signals to said plurality of said mobile terminals in a space domain based on said relation of their directions; and selecting the time division multiplexing and the space division multiplexing in the case where an angular difference between the mobile terminals in view from the base station exceeds a threshold value or a spatial correlation value between the mobile terminals is lower than a threshold value.