to a second receiver in a particular embodiment a source signal and an interference signal are qam modulated the modulation structure information of the interference signal is known to the receiver at the transmitter the source signal is precoded based on the known interference structure and a common mapping rule is implemented such that the received signal can be decoded at the receiver without requiring a modulo operation at either the transmitter or receiver application_number US 54427306 A description consider the scalar case dirty paper coding illustrated in fig1 described in detail in m costa u201c writing on dirty paper u201d ieee trans inform theory vol it 29 no 3 may 1983 and is hereby incorporated by reference the output of the precoder 100 is given as x v u2212 u03b1s where v is the input signal s denotes the known interference and u03b1 is a scalar multiplier to maximize the mutual information between y and v given the signal power p x and noise power p n we let c 1 2 u2062 log u2061 1 p x p n let u03bb denote an n dimensional lattice and let v denote its fundamental voronoi region also let u u02dc unif v that is u is a random variable dither uniformly distributed over v the dirty paper coding scheme may be implemented as follows transmitter the input alphabet is restricted to v for any v u2282 v the precoder sends where u is the common dither shared by the receiver and the transmitter and is uniformly districutred.