FIELD: radio engineering, communication.
SUBSTANCE: invention relates to multiple input multiple output (MIMO) mobile communication systems and is intended to improve efficiency of using precoding matrix information (PMI), and discloses a user device in a mobile communication system using MIMO and precoding, which includes a PMI indicator generator which generates PMI indicating the precoding matrix to be used by a base station; a transmitter which transmits the PMI as feedback to the base station; a receiver which receives a signal from the base station, wherein the signal received by the receiver contains information indicating if it corresponds to PMI transmitted as feedback from the user device, after a predefined period of time from the moment of transmitting PMI from the user device as feedback.
EFFECT: high efficiency of using precoding matrix information.
13 cl, 9 dwg
