In a transmission method according to one aspect of the present disclosure, a encoder performs error correction coding on an information bit string to generate a code word. A mapper modulates a first bit string in which the number of bits is the predetermined integral multiple of (X+Y) in the code word using a first scheme, the first scheme being a set of a modulation scheme in which an X-bit bit string is mapped to generate a first complex signal and a modulation scheme in which a Y-bit bit string is mapped to generate a second complex signal, and modulates a second bit string in which the first bit string is removed from the code word using a second scheme different from the first scheme.

A method and an apparatus for measuring a link quality in a wireless communication are provided. The method of a receiver for measuring the link quality in the wireless communication system includes determining a modulation type for each of at least one reception stream received through at least one antenna based on a modulation order and channel information regarding each of signals transmitted from a plurality of transmission antennas, searching for a parameter corresponding to the determined modulation type from a pre-stored parameter table in which parameters for each modulation type are stored, and calculating a channel capacity for each of the at least one reception streams received through the at least one antenna by using the searched parameter.

A reception device includes receivers and controller. Receivers receive a plurality of modulation signals modulated by a transmission device. Controller selects a communication scheme on the basis of phase difference between reception signals, which are the modulation signals received by the receivers, and of polarization plane deviation of the reception signals from transmission signals, which are the modulation signals transmitted from the transmission device, and sets, for the transmission device, a modulation scheme corresponding to the communication scheme.

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 2×2 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 2×2 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”.

A transmitter generates a first precoding vector for a first virtual antenna port among a plurality of virtual antenna ports using a first sequence having a constant magnitude and a discrete Fourier transform (DFT) vector sequence in a time domain and a frequency domain. The transmitter generates a plurality of second precoding vectors for the remaining virtual antenna port, except for the first virtual antenna port of the plurality of virtual antenna ports by circular shifting the first precoding vector. The transmitter maps a plurality of first data streams for the plurality of virtual antenna ports to a plurality of physical antenna ports using the first precoding vector and the plurality of second precoding vectors.

The present invention provides a method for mitigating inter-cell interference. To this end, the present invention can comprise a second signal transmission step in which, when a transmission symbol to be transmitted to a first receiver is S and a transmission symbol to be transmitted to a second receiver is Z, a symbol S2k (k is an integer) is transmitted to the first receiver through a first transmission antenna according to a first pattern, a symbol S2k* is transmitted to the first receiver through a second transmission antenna, a symbol S2k+1 is transmitted to the first receiver through a third transmission antenna, a symbol S2k+1* is transmitted to the first receiver through a fourth transmission antenna, and symbols Z4k to Z4k+3 and symbols Z4k* to Z4k+3* are transmitted to the second receiver through fifth to eighth transmission antennas according to a second pattern different from the first pattern.

A method and apparatus for implementing spatial processing with unequal modulation and coding schemes (MCSs) or stream-dependent MCSs are disclosed. Input data may be parsed into a plurality of data streams, and spatial processing is performed on the data streams to generate a plurality of spatial streams. An MCS for each data stream is selected independently. The spatial streams are transmitted via multiple transmit antennas. At least one of the techniques of space time block coding (STBC), space frequency block coding (SFBC), quasi-orthogonal Alamouti coding, time reversed space time block coding, linear spatial processing and cyclic delay diversity (CDD) may be performed on the data/spatial streams. An antennal mapping matrix may then be applied to the spatial streams. The spatial streams are transmitted via multiple transmit antennas. The MCS for each data stream may be determined based on a signal-to-noise ratio of each spatial stream associated with the data stream.

Provided is a method for mitigating inter-cell interference. To this end, a method can comprise: when a transmission symbol which will be transmitted to a first receiver is S.sub.k (k is an integer) and a transmission symbol which will be transmitted to a second receiver is Z.sub.k (k is an integer), a step for, with respect to a first pattern, transmitting symbol S.sub.k to the first receiver through a first transmission antenna and transmitting symbol S.sub.k* to the first receiver through a second transmission antenna; and a second signal transmission step for, with respect to a second pattern that is different from the first pattern, transmitting symbol Z.sub.k to the second receiver through a third transmission antenna and transmitting symbol Z.sub.k* to the second receiver through a fourth transmission antenna.

Embodiments relate to a data transmission method. A relay node receives information that is about an SCMA codebook used by the relay node and that is sent by a destination node. The relay node receives two or more source signals sent by two or more source nodes. The relay node performs network coding on the received two or more source signals. The relay node performs SCMA codebook mapping on a signal obtained after the network coding, so as to obtain at least two modulation symbols. The relay node sends to the destination node, the at least two modulation symbols obtained after the SCMA mapping.

Spatial spreading is performed in a multi-antenna system to randomize an “effective” channel observed by a receiving entity for each transmitted data symbol block. For a MIMO system, at a transmitting entity, data is processed (e.g., encoded, interleaved, and modulated) to obtain N.sub.D data symbol blocks to be transmitted in N.sub.M transmission spans, where N.sub.D≧1 and N.sub.M>1. The N.sub.D blocks are partitioned into N.sub.M data symbol subblocks, one subblock for each transmission span. A steering matrix is selected (e.g., in a deterministic or pseudo-random manner from among a set of L steering matrices, where L>1) for each subblock. Each data symbol subblock is spatially processed with the steering matrix selected for that subblock to obtain transmit symbols, which are further processed and transmitted via N.sub.T transmit antennas in one transmission span. The N.sub.D data symbol blocks are thus spatially processed with N.sub.M steering matrices and observe an ensemble of channels.