COMMUNICATION SYSTEM AND CHANNEL ESTIMATING METHOD THEREOF

A communication system includes at least one transmitting unit and at least one receiving unit. The at least one transmitting unit is configured to transmit at least one input signal after precoding it with at least one precoding matrix. The at least one receiving unit wirelessly coupled with the at least one transmitting unit is configured to receive the at least one precoded input signal, and generate at least one channel quality signal corresponding to the at least one precoded input signal, in which the at least one transmitting unit generates at least one magnitude information estimate or at least one phase information estimate or at least one of both for at least one channel state information according to the at least one channel quality signal, the at least one precoding matrix and at least one noise size signal.