To eliminate the problem of a multi-path, without complicating a configuration by combining the communication techniques of open loop and closed loop diversities and exchanging a plurality of signals which are generated in an encoding circuit.

A base station BST is provided with two pairs of four antennas AT1-AT4, an open loop diversity system is adopted by the pairs of antennas AT1, AT2 and AT3, AT4, and a closed loop diversity system is adopted to parts between the pairs. In an open-loop communication function, signals S1 and S2 having a weight W1 are respectively transmitted from a space time block encoding diversity STTD encoder 44 by times T' and 2T' through the use of the antenna AT1 and also the signal S having a weight W2 and negative and positive coupling values are respectively transmitted from the STTD encoder 46 by the time T' and 2T' through the use of the antenna AT2. In a closed-loop function, a user UST extracts the weights W1 and W2 from the signal S and returns them to the BST station, together with the SNR value from a channel evaluator 50.