Channel state information (CSI) feedback in a wireless communication system is disclosed. A precoding matrix is generated for multi-antenna transmission based on precoding matrix indicator (PMI) feedback, wherein the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first codebook and a second codebook. In one embodiment, the first codebook comprises at least a first precoding matrix constructed with a first group of adjacent Discrete-Fourier-Transform (DFT) vectors. In another embodiment, the first codebook comprises at least a second precoding matrix constructed with a second group of uniformly distributed non-adjacent DFT vectors. In yet another embodiment, the first codebook comprises at least a first precoding matrix and a second precoding matrix, where said first precoding matrix is constructed with a first group of adjacent DFT vectors, and said second precoding matrix is constructed with a second group of uniformly distributed non-adjacent DFT vectors.

Systems, methods, and other embodiments associated with a hybrid beamforming architecture are described. According to one embodiment, an apparatus comprises a beamforming architecture including a baseband unit and a processor. The beamforming architecture is configured to determine a steering matrix based on at least the baseband unit and the processor; and wherein the beamforming architecture is configured to simultaneously support a plurality of beamformee client devices, each beamformee client device beamformed by a beamformer with at least one of a beamformer hardware mode and a beamformer software mode and with at least one of a beamformer explicit mode and a beamformer implicit mode.

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.

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 scheme. 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 system that incorporates teachings of the subject disclosure may include, for example, accessing a group of de-coupling data stored in a memory of a communication device where the group of de-coupling data is mapped to corresponding use cases associated with the communication device, selecting de-coupling data from among the group of de-coupling data according to a determined use case of the communication device, generating a pre-distortion signal according to the selected de-coupling data, combining the pre-distortion signal with RF signals to generate pre-distorted RF signals, and transmitting the pre-distorted RF signals via a multi-port antenna of the communication device. Other embodiments are disclosed.

An embodiment of a system includes a first number of antennas, a transmitter, and a receiver. The antennas are each spaced from another of the antennas by approximately a distance and are configured to provide, at one or more wavelengths that are greater than twice the distance, a channel capacity that exceeds a saturation channel capacity. The transmitter is configured to generate a second number of signals each having a wavelength that is greater than twice the distance, the second number related to a third number of signal pipes, and to couple each of the second number of signals to a respective one of the antennas. And the receiver is configured to receive from at least one of the antennas a fourth number of signals each having a wavelength that is greater than twice the distance, and to recover information from each of the fourth number of signals, the fourth number being related to the third number.

An embodiment of a system includes a transmitter and a receiver that is remote from the transmitter. The transmitter includes a first number of transmit antennas and a signal generator. The transmit antennas are each spaced from another of the transmit antennas by approximately a distance and configured to provide, at one or more wavelengths that are greater than twice the distance, a channel capacity that exceeds a saturation channel capacity. And the signal generator is configured to generate a second number of signals each having a wavelength that is greater than twice the distance, the second number related to a third number of signal pipes, and to couple each of the second number of signals to a respective one of the transmit antennas. The receiver includes a fourth number of antennas and a signal analyzer. The receive antennas are each spaced from another of the receive antennas by approximately the distance, and are configured to provide, at one or more wavelengths that are greater than twice the distance, a channel capacity that exceeds the saturation channel capacity. And the signal analyzer is configured to recover information from each of the second number of signals received by at least one of the receive antennas over a respective one of the third number of signal pipes.

Embodiments of this application disclose a channel estimation method and apparatus, and relate to the field of communications technologies. The method may include: generating and sending indication information, where the indication information is used to indicate L space-frequency basis vectors for constructing an M×N-dimensional space-frequency vector; the space-frequency vector includes M N-dimensional precoding vectors, each precoding vector is used in one of M frequency bands, and the space-frequency vector is generated by performing a weighted combination on L space-frequency component vectors; each of the L space-frequency component vectors is a vector including M×N elements that are in one of the L space-frequency basis vectors, and each of the L space-frequency basis vectors is an N.sub.f×N-dimensional vector; the space-frequency basis vector is a three-dimensional oversampled (DFT) vector; and L≥2, N.sub.f≥M≥1, N≥2, and L, M, N, and N.sub.f are all integers.

Provided is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals to be transmitted over the same frequency bandwidth at the same time, including the steps of selecting a matrix F[i] from among N matrices, which define precoding performed on the plurality of baseband signals, while switching between the N matrices, i being an integer from 0 to N−1, and N being an integer at least two, generating a first precoded signal z1 and a second precoded signal z2, generating a first encoded block and a second encoded block using a predetermined error correction block encoding method, generating a baseband signal with M symbols from the first encoded block and a baseband signal with M symbols the second encoded block, and precoding a combination of the generated baseband signals to generate a precoded signal having M slots.

In this disclosure, methods for pre-compensation of the phase shifting error, and apparatuses for the same are disclosed. In one example, a device performs precoding of a digital signal, while acquiring information on an error caused by a phase shifting of the precoding. Then, the device performs phase compensation on the digital signal based on the acquired information. This phase compensated-digital signal is converted to an analog signal, and is transmitted to a receiver.