Abstract: According to one embodiment, a communication device communicates with N remote units. Each remote unit includes a plurality of antennas, wireless transmitting units, and wireless receiving units. The communication device is provided with a received signal processing unit, to which received signals by a plurality of the wireless receiving units are combined and input, and which specifies the remote unit subjected to interference, and a switch which decreases a reception gain of the wireless receiving unit included in N?1 remote units out of the N remote units in a predetermined measurement section. The received signal processing unit calculates a correlation value between the combined received signals and a reference signal transmitted by a user terminal connected to another base station system in the measurement section and specifies the remote unit subjected to the interference by the second user terminal based on the correlation value.

Abstract: A first extended base station that forms a first cell and a second extended base station that forms a second cell operate for a cooperative communication of transmitting same data to a user terminal located in the first cell. A second signal processor that corresponds to the second extended base station generates a training signal specific to the first extended base station and the first extended base station and the second extended base station transmit same data and same training signals. Thus, a cooperative communication can be realized in a system that uses a training signal specific to a base station.

Abstract: In one embodiment, there is provided a communication device configured to add a first perturbation signal corresponding to an integer multiple of a first basic signal, to a first information signal having first information, which is to be transmitted to a plurality of destination terminals, and transmit a wireless signal having the first information to the plurality of destination terminals by a spatial multiplexing method. The device includes: a determination unit configured to set a magnitude of the first basic signal to N times of one side of a basic lattice, wherein the basic lattice is determined according to a modulation method of the first information signal, and N is real number of one or more; an adder configured to add the first perturbation signal to the first information signal to output a second information signal; and a multiplier configured to multiply the second information signal by a weight.