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.

Techniques and apparatus for transmission and reception with partial allocation in orthogonal frequency division multiple access (OFDMA)/single-carrier frequency division multiple access (SC-FDMA) systems are provided. One technique includes determining first parameter(s) to apply to transmission/receive processing of a signal, based in part on a resource allocation for the signal. The resource allocation is partitioned out of a larger system bandwidth. Second parameter(s) to apply to the transmission/receive processing are determined based at least in part on the first parameter(s). Transmission/receive processing of the signal is performed in accordance with the first and second parameters.

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 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 method for transmitting a demodulation reference signal (DM-RS), by a user equipment (UE), in a wireless communication system is discussed. The method includes receiving, by the UE from a base station, a cyclic shift field in downlink control information (DCI), wherein the cyclic shift field indicates first, second, and third cyclic shift values for first, second, and third layers respectively, generating, by the UE, first, second, and third DMRSs for the first, second, and third layers respectively, based on first, second, and third cyclic shifts respectively, wherein the first, second, and third cyclic shifts are determined based on the first, second, and third cyclic shift values respectively, and transmitting, by the UE to the base station, the first, second, and third DMRSs.

An OFDM modulator including a predistortion module configured to receive the N.sub.c consecutive data carriers and configured to compensate for distortion subsequently introduced by a polyphase filter bank connectable to the output of the OFDM modulator, a transformation module configured to apply a discrete inverse Fourier transform of constant size N.sub.IDFT independently of the numbering and transmission band used by the OFDM transmitter including the OFDM modulator, a filling module, the input of which is connected to the output of the predistortion module, and the output of which is connected to the input of the transformation module, and configured to insert (N.sub.IDFT?N.sub.c) null carriers in succession to the N.sub.c consecutive data carriers independently of the parity of the index i associated with the OFDM modulator.

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.

Disclosed is a method for a station (STA) device transmitting data in a Wireless Local Area Network (WLAN) system. The method for transmitting data, according to one embodiment of the present invention, comprises the steps of: FEC encoding transmission data; interleaving the transmission data; constellation mapping the transmission data; performing IDFT on the transmission data; and upconverting the transmission data and transmitting a transmission signal, wherein the transmission signal comprises a first part and a second part, and IDFT is performed using different FFT sizes for the first part and the second part.

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 FBMC transmission/reception system wherein a phase pre-compensation and an amplitude pre-compensation are done on a block of modulation symbols. The symbol block thus compensated is segmented into a number M of sub-blocks equal to the number of carriers of an FBMC modulator. The sub-blocks are divided into vectors with size N/2 and padded with isolation zeroes to form padded vectors with size N. Each of these padded M is processed by an IFFT to give time sequences to which cyclic prefixes and suffixes are added. The resulting cyclic sequences are then input to the M input channels of the FBMC modulator. The reception symbols can be recovered at the receiver by a simple FFT with size NM/2.