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 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 constellation mapping method, system, and apparatus are provided for mapping a received bit stream of data to a higher order symbol vector by processing a first set of selected bits from the received bit stream with a quadrant selector to identify a first quadrant offset vector corresponding a higher order quadrant in which an intended symbol is to be mapped, processing a second set of selected bits from the received bit stream with a 16-QAM mapper to identify a 16-QAM symbol vector, transforming the 16-QAM symbol vector into a transformed 16 QAM symbol vector based on the identified higher order quadrant, and combining the transformed 16-QAM symbol vector with the first quadrant offset vector to map the bit stream of data to a higher order symbol vector.

Probabilistic shaping quadrature amplitude modulation (QAM) based on Maxwell-Boltzmann distribution is particularly important in coherent optical communication, which can approach the Shannon limit more desirably in the case of a finite signal-to-noise ratio. However, standard coherent optical digital signal processing algorithms are not optimal for demodulation of PS higher-order QAM signals. The invention provides a probabilistic shaping QAM dynamic equalization method that intercepts multiple inner rings after clock recovery and updates the convergence radius and area of a conventional blind dynamic channel equalization algorithm using a peak density K-means clustering algorithm. The clustering algorithm gives centroid labels and a quantity of classifications required for K-means, which does not require a large number of iterations of K-means, thereby reducing the complexity and improving the accuracy. The updated decision area and decision radius reduce errors in the dynamic equalization algorithm, thereby improving the accuracy of probabilistic shaping QAM digital signal processing.

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 method is provided of receiving user data from multiple transmitters, the user data from each transmitter having been encoded as a Low Density Lattice codeword, and the multiple Low Density Lattice codewords having been transmitted so as to be received as a combined signal at a receiver, the method of receiving comprising the steps of: (i) receiving the signal, (ii) calculating coefficients of linear combinations of the codewords from the multiple transmitters, (iii) calculating a scaling factor to be applied to the signal based on the coefficients, (iv) applying the scaling factor to the signal to provide a linear combination of the codewords, (v) decoding the linear combination of the codewords based on channel state information to obtain an optimal independent linear combination of user data, (vi) repeating steps (ii), (iii) (iv) and (v) to obtain at least as many optimal independent linear combinations as the number of transmitters, and recovering the user data from the optimal independent linear combinations.

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.

Methods and apparatus for facilitating wireless communication using digital Quadrature Amplitude Modulation are disclosed. A mapping module electronic component of 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. Specific signal constellations are disclosed. The signal constellations may be obtained through an optimization procedure which accounts for both phase noise and power amplifier nonlinearity.

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.

Methods and apparatus for facilitating wireless communication using digital Quadrature Amplitude Modulation are disclosed. A mapping module electronic component of 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. Specific signal constellations are disclosed. The signal constellations may be obtained through an optimization procedure which accounts for both phase noise and power amplifier nonlinearity.