A modulator and a modulation method using a non-uniform 16-symbol signal constellation are disclosed. The modulator includes a memory and a processor. The memory receives a codeword corresponding to a low-density parity check (LDPC) code having a code rate of 4/15. The processor maps the codeword to 16 symbols of the non-uniform 16-symbol signal constellation on a 4-bit basis.

A transmission device that improves data reception quality includes: a weighting synthesizer that generates a first precoded signal and a second precoded signal from a first baseband signal and a second baseband signal, respectively; a phase changer that applies a phase change of i×Δλ to the second precoded signal; an inserter that inserts a pilot signal into the second precoded signal applied with the phase change; and a phase changer that applies a phase change to the second precoded signal applied with the phase change and inserted with the pilot signal. Δλ satisfies π/2 radians<Δλ<π radians or π radians<Δλ<3π/2 radians. Each of the first baseband signal and the second baseband signal is modulated via a modulation scheme of quadrature amplitude modulation (QAM) using non-uniform mapping.

A transmission device that improves data reception quality includes: a weighting synthesizer that generates a first precoded signal and a second precoded signal from a first baseband signal and a second baseband signal, respectively; a phase changer that applies a phase change of i×Δλ to the second precoded signal; an inserter that inserts a pilot signal into the second precoded signal applied with the phase change; and a phase changer that applies a phase change to the second precoded signal applied with the phase change and inserted with the pilot signal. Δλ satisfies π/2 radians<Δλ<π radians or π radians<Δλ<3π/2 radians. Each of the first baseband signal and the second baseband signal is modulated via a modulation scheme of quadrature amplitude modulation (QAM) using non-uniform mapping.

Methods and apparatus for facilitating wireless communication using digital Quadrature Amplitude Modulation are disclosed. A wireless communication device utilizes a signal constellation for quadrature modulating a signal for transmission or quadrature demodulating a received signal. The signal constellation includes multiple constellation symbols and associated bit sequences, which can be translated there between. Specific signal constellations are disclosed.

The disclosure relates to a transmitting communication apparatus and a receiving communication apparatus of a non-coherent communication system. The transmitting communication apparatus is configured to communicate with the receiving communication apparatus via a communication channel. The transmitting communication apparatus comprises a processing circuitry configured to: map a sequence of data bits into a modulation symbol of a plurality of modulation symbols defined by a modulation constellation, wherein the modulation constellation is defined by a tiling of a Grassmannian manifold into a plurality of cells and a Cartesian product of a plurality of auxiliary constellations, wherein the Cartesian product of the plurality of auxiliary constellations is mapped onto each cell of the plurality of cells and each auxiliary constellation defines a plurality of auxiliary symbols. The processing circuitry is further configured to transmit a modulated signal based on the modulation symbol via the communication channel to the receiving communication apparatus.

A transmission device that improves data reception quality includes: a weighting synthesizer that generates a first precoded signal and a second precoded signal from a first baseband signal and a second baseband signal, respectively; a phase changer that applies a phase change of i to the second precoded signal; an inserter that inserts a pilot signal into the second precoded signal applied with the phase change; and a phase changer that applies a phase change to the second precoded signal applied with the phase change and inserted with the pilot signal. satisfies /2 radians<< radians or radians<<3/2 radians. Each of the first baseband signal and the second baseband signal is modulated via a modulation scheme of quadrature amplitude modulation (QAM) using non-uniform mapping.

A technique for performing data modulation is described. As to a method aspect of the technique, n bits of data are mapped to one modulation symbol (502) out of a modulation alphabet comprising 2.sup.n modulation symbols (502). The modulation alphabet corresponds to a finite subset of a hexagonal lattice in a constellation plane (500) spanned by an in-phase value (506) and a quadrature value (508) of a signal. All modulation symbols (502) are spaced apart in the constellation plane (500) from a direct current, DC, component corresponding to zero in-phase value and zero quadrature value. The signal corresponding to the mapped modulation symbol (502) is output.

A transmission device that improves data reception quality includes: a weighting synthesizer that generates a first precoded signal and a second precoded signal from a first baseband signal and a second baseband signal, respectively; a phase changer that applies a phase change of i to the second precoded signal; an inserter that inserts a pilot signal into the second precoded signal applied with the phase change; and a phase changer that applies a phase change to the second precoded signal applied with the phase change and inserted with the pilot signal. satisfies /2 radians<< radians or radians<<3/2 radians. Each of the first baseband signal and the second baseband signal is modulated via a modulation scheme of quadrature amplitude modulation (QAM) using non-uniform mapping.

A modulator and a modulation method using a non-uniform 16-symbol signal constellation are disclosed. The modulator includes a memory and a processor. The memory receives a codeword corresponding to a low-density parity check (LDPC) code having a code rate of 3/15. The processor maps the codeword to 16 symbols of the non-uniform 16-symbol signal constellation on a 4-bit basis.

A modulation device includes a mapping circuit configured to map information bits to signal points on a plurality of concentric rings, when a signal space arrangement in which the number of signal points on all of the plurality of rings is the same is used as a basis, reduce the number of signal points on an innermost ring or a plurality of rings from inner to outer rings from among the plurality of rings, generate a new ring outside the signal space arrangement used as the basis, and arrange, on the generated ring, signal points which achieve the same frequency utilization efficiency as that of the signal space arrangement used as the basis.