The disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4.sup.th-Generation (4G) communication system such as long term evolution (LTE). According to various embodiments, a transmission device in a wireless environment may include a transceiver, and a processor operatively coupled to the transceiver. The processor may be configured to generate a codeword related to transmission data, generate symbols from the codeword by using a plurality of transmission symbol vectors determined using a linear combination of vectors corresponding to respective rows of a lattice generation matrix, and transmit a signal generated based on the symbols via the transceiver.

A transmission method includes mapping processing, phase change processing, and transmission processing. In the mapping processing, a plurality of first modulation signals and a plurality of second modulation signals are generated using a first mapping scheme, and a plurality of third modulation signals and a plurality of fourth modulation signals are generated using a second mapping scheme. In the phase change processing, a phase change is performed on the plurality of second modulation signals and the plurality of fourth modulation signals using all N kinds of phases. In the transmission processing, the first modulation signals and the second modulation signals are respectively transmitted at a same frequency and a same time from different antennas, and the third modulation signals and the fourth modulation signals are respectively transmitted at a same frequency and a same time from the different antennas.

A coding and modulation apparatus and method are presented, particularly for use in a system according to IEEE 802.11. The apparatus comprises an encoder configured to encode input data into cell words according to a low density parity check code, LDPC, and a modulator configured to modulate said cell words into constellation values of a non-uniform constellation and to assign bit combinations to constellation values of the used non-uniform constellation, wherein said modulator is configured to use, based on the total number N of constellation points of the constellation and the code rate R, a particular non-uniform constellation, which has been optimized using the peak-to-average power ratio (PAPR).

A method of signal demodulation includes receiving, by a signal receiver, a first signal modulated by a symbol corresponding to a point in a constellation; generating, by the signal receiver and on the basis of the first signal, a first initial modulation estimate; identifying, by the signal receiver and on the basis of the first initial modulation estimate, a row or column of an initial candidate lookup table, the row or column corresponding to a region of the constellation; reading, by the signal receiver, from the row or column of the initial candidate lookup table one or more first initial candidate points of the constellation, at least one among the one or more first initial candidate points being more distant, from a center of the region, than a point, in the constellation, not among the one or more first initial candidate points, and demodulating, by the signal receiver and on the basis of the one or more first initial candidate points, the first signal.

Provided are a transmitter and a method for transmitting a data block in a wireless communication system. The method comprises the following steps: deciding the number of bits (s) and encoders (N.sub.ES) to allocate to one axis of a signal constellation; encoding an information bit based on the s and the N.sub.ES and generating a coded block; parsing the coded block based on the s and the N.sub.ES and generating a plurality of frequency sub-blocks; and transmitting the plurality of frequency sub-blocks to a receiver.

Quadrature amplitude modulation (QAM) techniques for use in optical systems are described. An optical transceiver may include a modulator configured to modulate data according to a scaled set-partitioning QAM (SP-QAM) scheme. The modulator may be configured to receive a plurality of bits, associate the plurality of bits with a plurality of symbols according to the scaled (SP-QAM) scheme; and transmit the plurality of symbols over an optical channel. A demodulator in an optical receiver may receive the plurality of symbols transmitted over the optical channel and associate the received symbols with a plurality of bits according to the scaled (SP-QAM) scheme; and provide the plurality of bits to a forward error correction decoder.

A method (C) for converting a data signal (U). The method comprises processes of (i) providing an input bit stream (IB) of input bits (IBj), the input bit stream (IB) being representative for the underlying data signal (U) to be converted, and (ii) applying to consecutive disjunct partial input bit sequences (IB.sup.k) of a number of k consecutive input bits (IBj) covering said input bit stream (IB) a distribution matching process (DM) to generate and output a final output bit stream (OB) or a preform thereof. The distribution matching process (DM) is formed by a quadrant constellation shaping process (QS) and configured to map a respective partial input bit sequence (IB.sup.k) to a constellation point of a four-dimensional 2.sup.4.Math.m-QAM constellationin particular conveying two distinct polarizations for each of an in-phase and a quadrature componentwith I and m being fixed natural numbers and with k and m fulfilling the relation 4.Math.mk.

A transmission method includes mapping processing, phase change processing, and transmission processing. In the mapping processing, a plurality of first modulation signals and a plurality of second modulation signals are generated using a first mapping scheme, and a plurality of third modulation signals and a plurality of fourth modulation signals are generated using a second mapping scheme. In the phase change processing, a phase change is performed on the plurality of second modulation signals and the plurality of fourth modulation signals using all N kinds of phases. In the transmission processing, the first modulation signals and the second modulation signals are respectively transmitted at a same frequency and a same time from different antennas, and the third modulation signals and the fourth modulation signals are respectively transmitted at a same frequency and a same time from the different antennas.

A system and method for receiving a quadrature amplitude modulation symbol. In some embodiments, the symbol has a plurality of bits and is associated with a point in a constellation of quadrature amplitude modulation points, each point of the constellation having associated with it a binary word. The method includes receiving a first analog signal carrying a modulation; performing initial estimation, to generate a first initial modulation estimate, for a portion of the first analog signal carrying a modulation; identifying, based on the first initial modulation estimate, a row of an initial candidate lookup table, the row corresponding to a region of the constellation; and reading from the row of the initial candidate lookup table a first plurality of initial candidate points of the constellation.

The present disclosure provides an encoding method and an encoder for a (n, n(n1), n1) permutation group code in a communication modulation system, in which 2.sup.k k-length binary information sequences are mapped to 2.sup.k n-length permutation codeword signal points in a n-dimensional modulation constellation .sub.n. The constellation .sub.n with the coset characteristics is formed by selecting 2.sup.k n-length permutation codewords from n(n1) permutation codewords of a code set P.sub.n,x.sub.i of the (n, n(n1), n1) permutation group code based on coset partition. The constellation .sub.n is a coset code in which 2.sup.k.sup.1 cosets are included and each coset includes 2.sup.k.sup.2 permutation codewords, where k=k.sub.1+k.sub.2, and 2.sup.kn(n1). The present disclosure utilizes the coset characteristics to realize one-to-one correspondence mapping of the binary information sequence set to the permutation code constellation, so that the time complexity of executing the encoder is at most the linear complexity of the code length n.