A reception device includes: a receiver that receives a multiplexed signal; a first demapper that demaps the multiplexed signal, with a second modulated symbol stream being included in the multiplexed signal as an undetermined signal component, to generate a first bit likelihood stream; a second demapper that demaps the multiplexed signal, with a first modulated symbol stream being included in the multiplexed signal as an undetermined signal component, to generate a second bit likelihood stream; a first decoder that performs error control decoding on the first bit likelihood stream; and a second decoder that performs error control decoding on the second bit likelihood stream. The multiplexed signal is a signal on which the first modulated symbol stream and the second modulated symbol stream are superposed, the second modulated symbol stream being subjected to conversion in accordance with the first modulated symbol stream in only a first direction.

Provided are a method and apparatus for transmitting data in a wireless communication system. The method, performed by a transmission apparatus, of transmitting data includes performing π/2-binary phase shift keying (BPSK) modulation on M symbols, performing a discrete Fourier transform (DFT) on the M symbols on which the π/2-BPSK modulation has been performed, performing an inverse fast Fourier transform (IFFT) on M/2 symbols among the M symbols on which the DFT has been performed, and transmitting, to a reception apparatus, the M/2 symbols on which the IFFT has been performed, wherein a constellation of the M symbols on which the π/2-BPSK modulation has been performed may have only real components or imaginary components.

A detection method for a MIMO system receiver in which a linear detection is carried out in order to provide an equalised vector. This equalised vector is represented in a reduced basis obtained from the reduction of the channel matrix. It undergoes an iterative noise cancellation process in the representation according to the reduced basis. Upon each iteration, a search is carried out for the component of the equalised vector in the reduced basis located the furthest from an area unperturbed by noise surrounding the product constellation with a tolerance margin, and the point representative of the equalised vector of this area by subtracting therefrom a noise vector in the direction of this component, the module whereof is equal to a fraction of the tolerance margin. The iterative cancellation converges when the equalised vector belongs to the area unperturbed by noise.

Communication systems are described that use unequally spaced constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. One embodiment is a digital communications system including a transmitter transmitting signals via a communication channel, the transmitter including a coder capable of receiving user bits and outputting encoded bits at a rate, a mapper capable of mapping encoded bits to symbols in a constellation, and a modulator capable of generating a modulated signal for transmission via the communication channel using symbols generated by the mapper, wherein the constellation is unequally spaced and characterizable by assignment of locations and labels of constellation points to maximize parallel decode capacity of the constellation at a given signal-to-noise ratio so that the constellation provides a given capacity at a reduced signal-to-noise ratio compared to a uniform constellation that maximizes the minimum distance between constellation points of the uniform constellation.

A signal detection method for a MIMO-OFDM wireless communication system includes obtaining a channel matrix of each subcarrier through channel estimation for each MIMO-OFDM data packet in a plurality of MIMO-OFDM data packets; receiving a reception vector of each subcarrier; performing channel matrix preprocessing for the channel matrix of each subcarrier to generate a global dynamic K-value table, in which the global dynamic K-value table includes a global dynamic K-value corresponding to each search layer of each subcarrier; performing MIMO detection for each OFDM symbol in the MIMO-OFDM data packet, in which the MIMO detection includes performing the following steps for each subcarrier of a current OFDM symbol: reading channel matrix preprocessing results and reception vector of the current subcarrier; transforming the reception vector of the current subcarrier into an LR search domain; and performing K-best search for the current subcarrier to obtain an LR domain candidate transmission vector of the current subcarrier, in which a K-value applied to each search layer of the current subcarrier during the K-best search is a global dynamic K-value in the global dynamic K-value table corresponding to the search layer.

A communication device includes an acquisition unit that acquires a bit sequence, and a conversion unit that converts the bit sequence to a predetermined complex constellation point sequence including a plurality of complex constellation points including a non-zero complex constellation point and a zero complex constellation point. At least one of the predetermined complex constellation point sequences is a first complex constellation point sequence in which each of a plurality of complex constellation points constituting the complex constellation point sequence is converted to any complex constellation point or zero complex constellation point of a first signal constellation including non-power of two number of complex constellation points. The conversion unit converts one of the bit sequences to at least the first complex constellation point sequence.

A communication device communicates a physical (PHY) frame including a preamble and a data field. The preamble includes a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), an EHT Signal Field (EHT-SIG-A), an EHT Short Training Field (EHT-STF), and an EHT Long Training Field (EHT-LTF) and the EHT-SIG-A includes fields indicating a modulation scheme and information indicating which one of a UC (Uniform Constellation) scheme and an NUC (Non Uniform Constellation) scheme is used as the modulation scheme, and the data field includes data that has undergone modulation corresponding to the modulation scheme and the information indicated by the fields.

Communication systems are described that use unequally spaced constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. One embodiment is a digital communications system including a transmitter transmitting signals via a communication channel, the transmitter including a coder capable of receiving user bits and outputting encoded bits at a rate, a mapper capable of mapping encoded bits to symbols in a constellation, and a modulator capable of generating a modulated signal for transmission via the communication channel using symbols generated by the mapper, wherein the constellation is unequally spaced and characterizable by assignment of locations and labels of constellation points to maximize parallel decode capacity of the constellation at a given signal-to-noise ratio so that the constellation provides a given capacity at a reduced signal-to-noise ratio compared to a uniform constellation that maximizes the minimum distance between constellation points of the uniform constellation.

Communication systems are described that use unequally spaced constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. One embodiment is a digital communications system including a transmitter transmitting signals via a communication channel, the transmitter including a coder capable of receiving user bits and outputting encoded bits at a rate, a mapper capable of mapping encoded bits to symbols in a constellation, and a modulator capable of generating a modulated signal for transmission via the communication channel using symbols generated by the mapper, wherein the constellation is unequally spaced and characterizable by assignment of locations and labels of constellation points to maximize parallel decode capacity of the constellation at a given signal-to-noise ratio so that the constellation provides a given capacity at a reduced signal-to-noise ratio compared to a uniform constellation that maximizes the minimum distance between constellation points of the uniform constellation.

Communication systems are described that use unequally spaced constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. One embodiment is a digital communications system including a transmitter transmitting signals via a communication channel, the transmitter including a coder capable of receiving user bits and outputting encoded bits at a rate, a mapper capable of mapping encoded bits to symbols in a constellation, and a modulator capable of generating a modulated signal for transmission via the communication channel using symbols generated by the mapper, wherein the constellation is unequally spaced and characterizable by assignment of locations and labels of constellation points to maximize parallel decode capacity of the constellation at a given signal-to-noise ratio so that the constellation provides a given capacity at a reduced signal-to-noise ratio compared to a uniform constellation that maximizes the minimum distance between constellation points of the uniform constellation.