Patent ID: 8199848

Claim:
A precoder for precoding a transmission signal when a transmission part transmits the transmission signal to a receiving part in a wireless communication system, the precoder comprising: an interference signal real channel generator for extracting an interference signal to be acted on a first user's transmission signal by using the first user's transmission signal and a transmitted signal of at least one second user who has transmitted a signal prior to the first user; a rotary angle selector for selecting a rotary angle for rotating a constellation of the first user's transmission signal by using information on a number of rotary angle types extracted based on channel information for a plurality of users including the first user and the interference signal; a modulo operator for eliminating the interference signal from the first user's transmission signal; and a matrix multiplier for using the first user's transmission signal from which the interference signal is eliminated, to transmit the first user's transmission signal to the receiving part by rotating a constellation by the selected rotary angle.