A method for transmitting and receiving signals in an open-loop spatial multiplexing transmission mode is described. If the number of transmit antennas is 2 and a rank is 2, a base station performs precoding according to a cyclic delay diversity scheme by a matrix in which a first matrix corresponding to an identity matrix, a second matrix corresponding to a diagonal matrix, and a third matrix corresponding to a unitary matrix are sequentially multiplied and transmits the precoded signals. This may be substantially the same as the case where the base station performs precoding using a matrix in which the second matrix corresponding to the diagonal matrix and the third matrix corresponding to the unitary matrix are multiplied and transmits the precoded signals. A user equipment estimates a transmission mode according to the received rank indicator and the number of transmit antennas and receives signals.