An apparatus for controlling an equalizer is provided. The apparatus comprises interface circuitry configured to receive at least one of an input signal and an output signal of the equalizer. The apparatus further comprises processing circuitry configured to determine at least one signal metric based on the at least one of the input signal and the output signal of the equalizer, select an operating mode of the equalizer from a plurality of different operating modes based on the determined signal metric, and control the equalizer to operate in the selected operating mode.

Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.

This invention presents methods for using spatial FFT to reduce the number of computations for generating the pre-coding matrix in a MIMO system comprising reducing the dimension of channel vectors by neglecting entries whose values are significantly smaller or near zero, and to select UEs into a group assigned to the same time and frequency resources.

Provided a method in a mobile communication system comprising a base station adapted to create a precoding matrix for applying to data to be transmitted to a user terminal by using a channel estimate determined from a Reference Signal (RS) transmitted from the user terminal to the base station, the user terminal being adapted to transmit to the base station a Channel State Information (CSI) report, wherein the method comprises: the base station creating a relationship between the received CSI report and Interference pluses Noise covariance matrix that reflects amount of interference and noise observed at the user terminal's antennas, the base station determining the Interference pluses Noise covariance matrix based on the created relationship, and the base station using the determined Interference pluses Noise covariance matrix to estimate SINR for each data layer conditioned on the precoding matrix.

A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having 1-layer, 2-layer, 3-layer, and 4-layer codebooks for 4 transmit antenna (4TX) transmission, each codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each of the 1-layer and 2-layer codebooks comprises a first codebook and a second codebook, and wherein each precoding matrix in the first codebook comprises a first index and a second index. Other apparatuses, systems, and methods also are disclosed.

A method performed by a base station of enabling a User Equipment (UE) to determine a precoder codebook in a wireless communication system is provided. The base station transmits, to the UE, information regarding precoder parameters enabling the UE to determine the precoder codebook. The precoder parameters are associated with a plurality of antenna ports of the base station. The precoder parameters relate to a first dimension and a second dimension of the precoder codebook. The plurality of antenna ports comprises a number of antenna ports that is a function of a number of antenna ports in the first dimension, and a number of antenna ports in the second dimension.

A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation sheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

A first wireless communication device includes transceiver circuitry to access data corresponding to a beamforming transmission, transmit, from the first wireless communication device to at least one second wireless communication device, a first sounding packet, and receive, from the at least one second wireless communication device, at least one second sounding packet. The second sounding packet includes channel feedback determined at the at least one second wireless communication device. Processor circuitry is to determine a steering matrix based on the channel feedback. The steering matrix is configured to at least one of reduce and avoid interference caused at the at least one second wireless communication device by transmissions from the first wireless communication device. The transceiver circuitry is further to perform the beamforming transmission to at least one third wireless communication device in accordance with the data corresponding to the beamforming transmission and the steering matrix.

A method for receiving a signal by integer forcing in a wireless communication system is provided. The method includes receiving one or more signals through a plurality of antennas, filtering the received one or more signals using a forcing matrix, generating codewords by remapping the filtered one or more signals, acquiring a summed codeword by performing a modulo operation on the codewords, decoding the summed codeword, and acquiring original codewords by performing an inversion operation on the decoded summed codeword.

A method performed by a base station of enabling a User Equipment, UE, to determine a precoder codebook in a wireless communication system is provided. The base station transmits (303) to the UE, information regarding precoder parameters enabling the UE to determine the precoder codebook. The precoder parameters are associated with a plurality of antenna ports of the base station. The precoder parameters relate to a first dimension and a second dimension of the precoder codebook. The plurality of antenna ports comprises a number NT of antenna ports that is a function of a number Nh of antenna ports in the first dimension, and a number Nv of antenna ports in the second dimension.