The proposed solution relates to a method and an apparatus in a communication system. The solution includes receiving as an input a frame including of a set of data symbols and reference symbols, each data symbol forming a rectangular symbol constellation of samples, derotating the first symbol of the set on the basis of the reference symbols, and setting phase rotating angle of the first symbol as zero. The solution further includes for each following successive symbol in the set of symbols: performing equalization; reducing the number of samples in the constellation by selecting samples in two or more corners of the constellation by utilising two or more threshold values; estimating the phase rotating angle of the symbol from the reduced number of samples and derotating the symbol on the basis of the determined phase rotating angle.

A transmitting apparatus for modulating data based on a predetermined 2.sup.q-QAM constellation and a receiving apparatus and method for demodulating a signal based on the predetermined 2.sup.q-QAM constellation, wherein the last q-2 bits corresponding to a quadrant of the predetermined 2.sup.q-QAM constellation are same with a gray code of a 2.sup.q-2-QAM constellation, the last q-2 bits corresponding to the remaining quadrants of the predetermined 2.sup.q-QAM constellation are determined by performing symmetric transformation for the last q-2 bits of the quadrant of the predetermined 2.sup.q-QAM around the x-axis or the y-axis.

Disclosed is a method, performed by a transmit node, for transmitting N+1 bits to a receive node. N is a positive integer. The method comprises producing a modulation element by mapping the N+1 bits to a constellation point of a N-dimensional tuneable constellation, wherein the N-dimensional tuneable constellation is derived using a constellation tuning parameter. The method comprises determining, based on N, one or more physical resource elements for the modulation element. The method comprises transmitting, to the receive node, the modulation element, using the physical resource elements.

Architectures for inter-converting bitstreams and symbol streams of PAM and/or QAM constellations of different sizes that are not base-2 integers. Some of such constellations may be Gray-coded, and the constellation mapping may be performed to achieve an equiprobable distribution of different constellation symbols. Some embodiments may be compatible with FEC schemes. In an example embodiment, a transmitter DSP may employ a conventional constellation mapper preceded by an electronic encoder programmed to exclude some constellation-symbol labels from the bitstream applied to the mapper. In different embodiments, the electronic encoder may employ a CCDM and/or a long-division operation to select some amplitudes of the constellation and to exclude others. At least some embodiments are beneficially capable of achieving a smaller gap to the Shannon limit than comparable conventional solutions.

A method by which a terminal demodulates a signal in a wireless access system according to one embodiment of the present invention comprises the steps of: receiving a modulation signal having a modulation order of 2.sup.m (m is a natural number); determining a first demodulation constellation arrangement corresponding to a k.sup.th (k is an even number among natural numbers of m or less) bit among m numbers of bits; determining a second demodulation constellation arrangement corresponding to an nth (n is an odd number among natural numbers of m or less) bit among the m numbers of bits; and demodulating the received modulation signal by using the first and second demodulation constellation arrangements, wherein the first constellation arrangement can have a pattern in which a square matrix having a size of 2.sup.(m/2+1)(k/2) is repeated.

The present disclosure relates to a 5G or pre-5G communication system to be provided for supporting a higher data transfer rate beyond a 4G communication system such as LTE. The present invention relates to a NOMA system based FQAM connection method and an apparatus therefor. The present invention can increase the user transfer rate at a cell boundary. The scheduling method in a wireless communication system, according to an embodiment of the present invention, comprises a step of receiving a signal-to-interference-noise ratio (SINR) value and an alpha value from a terminal; a step of determining, on the basis of the SINR value and the alpha value, a Gaussian SINR value; a step of pairing users on the basis of the Gaussian SINR value; and a step of re-computing MCS on the basis of a re-computed alpha value.

A method of spatially multiplexing data comprising a signal vector, the method comprising selecting first and second modulation schemes for the data transmission wherein the second modulation scheme is an interpolation in the plane of the first modulation scheme; and further wherein the modulation schemes are selected so as to maintain the same minimum Euclidean distance between vectors comprising the first and second modulation schemes as the minimum Euclidean distance within the first and second modulation schemes; and selecting a plurality of antennae, each of the plurality to concurrently transmit respective symbols of the signal vector.

An apparatus for transmitting a signal in accordance with an embodiment of the present invention includes a mapper configured to map a modulation symbol to a bit signal by referencing the constellation. The constellation includes a plurality of blocks, and each block includes constellation points, each of which has in-phase (I) axis component value and quadrature-phase (Q) axis component value whose difference from the I axis or Q axis component value of a reference point of the block is a first difference value or a second difference value.

Provided in the embodiments of the present application are a data modulation method, a data modulation apparatus, a computer-readable storage medium and a computer program product. The method comprises: modulating a data sequence by using N constellation point modulation symbols {S(n)}, so as to obtain K modulated data symbols [x(k)], wherein the N constellation point modulation symbols comprise two groups of modulation symbols, the phase difference between the two groups of modulation symbols being a preset angle, and N is an even number greater than or equal to 4, n is any integer from 0 to N1, K represents the number of modulated data symbols, K is an integer, and k is any integer from 0 to K1; performing a filtering operation on the modulated data symbols, so as to obtain filtered data; and transmitting the filtered data on a physical resource.

Disclosed is a method, performed by a transmit node, for transmitting N+1 bits to a receive node. N is a positive integer. The method comprises producing a modulation element by mapping the N+1 bits to a constellation point of a N-dimensional tuneable constellation, wherein the N-dimensional tuneable constellation is derived using a constellation tuning parameter. The method comprises determining, based on N, one or more physical resource elements for the modulation element. The method comprises transmitting, to the receive node, the modulation element, using the physical resource elements.