A MIMO communication method for performing MIMO communication between a base station including a plurality of antennas, and a plurality of terminals accommodated in the base station. The method includes, in the base station, dividing the plurality of terminals into a first and a second group, and assigning orthogonal codes with each other to the respective groups, spreading transmission data to the plurality of terminals with the assigned codes, multiplying data obtained by the spreading by a predetermined pre-coding matrix, obtaining a channel matrix representing channels between the plurality of antennas and the plurality of terminals, multiplying data obtained by the multiplying by the pre-coding matrix by a complex conjugate matrix of the channel matrix, and transmitting data obtained by the multiplying by the complex conjugate matrix from the plurality of antennas.

An embodiment of a transmitter includes a first number of antennas and a signal generator. 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 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 being related to a third number of signal pipes. And the signal generator is configured to couple each of the signals to a respective one of the antennas. Such a transmitter can be a multiple-input-multiple-output orthogonal-frequency-division-multiplexing (OFDM-MIMO) transmitter that can be configured to increase the information-carrying capacity of a channel (i.e., increase the channel capacity) above and beyond a saturation capacity of the channel.

An embodiment of a receiver includes a first number of antennas and a signal analyzer. 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 signal analyzer is configured to recover information from a second number of signals each received by at least one of the antennas over a respective one of a third number of signal pipes, and each having a wavelength that is greater than twice the distance, the second number being related to the third number. Such a receiver can be a multiple-input-multiple-output orthogonal-frequency-division-multiplexing (OFDM-MIMO) receiver that can be configured to increase the information-carrying capacity of a channel (i.e., increase the channel capacity) above and beyond a saturation capacity of the channel.

Methods and systems for signal transmission in millimeter wave (mmW) range. A set of sequences is used to encode a data signal for one layer in a group of layers. Each sequence in the set of sequences has a length equal to the number of resources shared among the group of layers. At least a portion of the sequences have a low density of non-zero values, and the non-zero values are assigned to a subset of the shared resources. Each sequence assigns a non-zero value to at most one resource of the subset of shared resources, and all non-zero values assigned by all sequences have equal power amplitudes.

Embodiments include methods for a network node configured to communicate with wireless devices via orthogonal frequency division multiple access (OFDMA) signaling and non-OFDMA signaling. Such methods include creating a frequency gap in the OFDMA signaling, with the frequency gap including one or more adjacent OFDM sub-carriers. Such methods include selecting a center frequency for the non-OFDMA signaling to be within the frequency gap and selecting one or more modulation and coding schemes (MCS) for the OFDMA signaling based on interference to the OFDMA signaling by the non-OFDMA signaling. Other embodiments include network nodes configured to perform such methods, and computer-readable media storing computer-executable instructions that embody such methods.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

The present disclosure discloses a codebook feedback method, a terminal device and a network device. The codebook feedback method, comprising: selecting, by a terminal device, M frequency domain Discrete Fourier Transform (DFT) vectors from a DFT array; determining, by the terminal device, a first frequency domain DFT vector indication set from a plurality of frequency domain DFT vector indication sets according to the M frequency domain DFT vectors, wherein an indication of the M frequency domain DFT vectors is equivalent to a first frequency domain DFT vector indication in the first frequency domain DFT vector indication set, and M is a positive integer; and sending, by the terminal device, an indication message to the network device, wherein the indication message is used for indicating the first frequency domain DFT vector indication set.

Embodiments of the present disclosure relate to a method and system to generate a waveform in a communication network. The transmitter receives an input data and transmit a generated waveform to another communication system. The input data is spread with a spread code to generate a spread data and rotated using a constellation rotation operation to produce a rotated data. The rotated data is then precoded using precoding filter to produce a precoded data, and transformed into DFT output data using DFT operation. The DFT output data is then mapped with subcarriers to generate the sub-carrier mapped DFT data and modulated using Orthogonal Frequency Division Multiplexing (OFDM) modulation to generate the waveform with low PAPR.

According to one embodiment, a synchronization circuit includes a received-signal detecting unit which detects a received signal including a first and a second reference signal, a timing-synchronization adjusting unit including a storage module storing information of the first reference signal and a correlation operating module carrying out correlation operation of the first reference signal included in the received signal and the information of the first reference signal output from the storage module, the timing-synchronization adjusting unit which carries out timing synchronization so that a result of the correlation operation carried out by the correlation operating module becomes a predetermined value, and a phase-synchronization adjusting unit which carries out phase synchronization of a subcarrier by adjusting a component varied depending on a phase of a subcarrier frequency by using a phase modulation signal included in the second reference signal, wherein the received signal is a filtered multicarrier signal.

A method and apparatus for multiple-access wireless transmission is disclosed. The method involves mapping a plurality of signals onto a multi-dimensional non-Gaussian source manifold, the plurality of signals including signals targeted for transmission to a plurality of receivers. The method also involves transforming the source manifold into a multi-dimensional target manifold using a polarization stream network. The method further involves generating a multiple-access transmission waveform for transmission to the plurality of receivers, the multiple-access transmission waveform being based on the target manifold.