An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.

Examples described herein include systems and methods which include wireless devices and systems with examples of full duplex compensation with a self-interference noise calculator. The self-interference noise calculator may be coupled to antennas of a wireless device and configured to generate adjusted signals that compensate self-interference. The self-interference noise calculator may include a network of processing elements configured to combine transmission signals into intermediate results according to input data and delayed versions of the intermediate results. Each set of intermediate results may be combined in the self-interference noise calculator to generate a corresponding adjusted signal. The adjusted signal is received by a corresponding wireless receiver to compensate for the self-interference noise generated by a wireless transmitter transmitting on the same frequency band as the wireless receiver is receiving.

A method and a device for transmitting a data unit are disclosed. A method for transmitting a PPDU can comprise the steps of: generating, by an STA, the PPDU including a first portion and a second portion; and transmitting, by the STA, the PPDU, wherein the first portion is generated by performing IFFT according to a first FFT size, the second portion is generated by performing IFFT according to a second FFT size, and the first FFT size can differ from the second FFT size.

A resource assignment method, a related device, and an apparatus. The method includes: receiving, by a terminal from a network device, a resource assignment indication used to indicate frequency domain resource assignment, where the resource assignment indication is used to indicate a plurality of first resource units assigned to the terminal and that the plurality of first resource units are categorized into one or more groups, where a quantity of first resource units in each group is a product of powers of 2, 3, and 5; and performing, by the terminal, discrete Fourier transform based on the plurality of first resource units. According to the resource assignment method , flexible resource assignment can be performed, and spectrum utilization can be improved.

Examples described herein include systems and methods which include wireless devices and systems with examples of full duplex compensation with a self-interference noise calculator. The self-interference noise calculator may be coupled to antennas of a wireless device and configured to generate adjusted signals that compensate self-interference. The self-interference noise calculator may include a network of processing elements configured to combine transmission signals into intermediate results according to input data and delayed versions of the intermediate results. Each set of intermediate results may be combined in the self-interference noise calculator to generate a corresponding adjusted signal. The adjusted signal is received by a corresponding wireless receiver to compensate for the self-interference noise generated b a wireless transmitter transmitting on the same, frequency band as the wireless receiver is receiving.

Examples described herein include systems and methods which include wireless devices and systems with examples of full duplex compensation with a self-interference noise calculator. The self-interference noise calculator may be coupled to antennas of a wireless device and configured to generate adjusted signals that compensate self-interference. The self-interference noise calculator may include a network of processing elements configured to combine transmission signals into intermediate results according to input data and delayed versions of the intermediate results. Each set of intermediate results may be combined in the self-interference noise calculator to generate a corresponding adjusted signal. The adjusted signal is received by a corresponding wireless receiver to compensate for the self-interference noise generated by a wireless transmitter transmitting on the same frequency band as the wireless receiver is receiving.

The present invention relates to a method for transmitting, by a base station, a downlink signal using a plurality of transmission antennas comprises the steps of: applying a precoding matrix indicated by the PMI, received from a terminal, in a codebook to a plurality of layers, and transmitting the precoded signal to the terminal through a plurality of transmission antennas. Among precoding matrices included in the codebook, a precoding matrix for even number transmission layers can be a 22 matrix containing four matrices (W1s), the matrix (W1) having rows of a number of transmission antennas and columns of half the number of transmission layers, the first and second columns of the first row in the 22 matrix being multiplied by 1, the first column of the second row being multiplied by coefficient a of a phase, and the first column of the second row being multiplied by a.

An operation method of a first communication node in a communication system may comprise generating a codeword by performing coding on a data stream; generating modulation symbols by performing modulation on the codeword; performing DFT on N modulation symbols among the modulation symbols by using a plurality of DFT units; mapping output symbols of each of the plurality of DFT units to a resource; and performing IFFT on the output symbols mapped to the resource by using an IFFT unit.

The present invention relates to a method for transmitting, by a base station, a downlink signal using a plurality of transmission antennas comprises the steps of: applying a precoding matrix indicated by the PMI, received from a terminal, in a codebook to a plurality of layers, and transmitting the precoded signal to the terminal through a plurality of transmission antennas. Among precoding matrices included in the codebook, a precoding matrix for even number transmission layers can be a 22 matrix containing four matrices (W1s), the matrix (W1) having rows of a number of transmission antennas and columns of half the number of transmission layers, the first and second columns of the first row in the 22 matrix being multiplied by 1, the first column of the second row being multiplied by coefficient a of a phase, and the first column of the second row being multiplied by a.

An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.