Method and apparatus for encoding a modulated signal in a communication system

A method for encoding a modulated signal to be transmitted from a transmitter to a receiver in a multi-user multi input multi output communication system, comprising:

• generating an initial constellation of the modulated signal, wherein the initial constellation has initial symbols defined by an initial symbol abscissa and an initial symbol ordinate;
• applying a vertical axis symmetry to the initial constellation to generate a first resulting constellation comprising first resulting symbols defined by a first resulting symbol abscissa and a first resulting symbol ordinate;
• translating the first resulting constellation to a left direction of the initial constellation to produce a left flipped constellation comprising left flipped symbols defined by a left flipped symbol abscissa and a left flipped symbol ordinate;
• applying a horizontal axis symmetry to the initial constellation to generate a second resulting constellation comprising second resulting symbols defined by a second resulting symbol abscissa and a second resulting symbol ordinate;
• and
• translating the second resulting constellation to an up direction of the initial constellation to produce an up flipped constellation comprising up flipped symbols defined by an up flipped symbol abscissa and an up flipped symbol ordinate;
• applying a central axis symmetry to the initial constellation to generate a third resulting constellation comprising third resulting symbols defined by a third resulting symbol abscissa and a third resulting symbol ordinate;
• and
• translating the third resulting constellation to a left-up direction of the initial constellation to produce a left-up flipped constellation comprising left-up flipped symbols defined by a left-up flipped symbol abscissa and a left-up flipped symbol ordinate,
• wherein the initial constellation, the left flipped constellation, the up flipped constellation, and the left-up flipped constellation define a super constellation, and
• wherein a first symbol of the super constellation is transmitted to the receiver using a dirty paper coding technique.

An apparatus for encoding a modulated signal to be transmitted from a transmitter to a receiver in a communication system, comprising:

• means for generating an initial constellation of the modulated signal, wherein the initial constellation has initial symbols defined by an initial symbol abscissa and an initial symbol ordinate;
• means for applying a vertical axis symmetry to the initial constellation to generate a first resulting constellation comprising first resulting symbols defined by a first resulting symbol abscissa and a first resulting symbol ordinate, wherein the first resulting symbol abscissa is an additive inverse of the initial symbol abscissa and the first resulting symbol ordinate has a same value of the initial symbol ordinate;
• means for translating the first resulting constellation to a left direction of the initial constellation to produce a left flipped constellation comprising left flipped symbols defined by a left flipped symbol abscissa and a left flipped symbol ordinate;
• means for applying a horizontal axis symmetry to the initial constellation to generate a second resulting constellation comprising second resulting symbols defined by a second resulting symbol abscissa and a second resulting symbol ordinate, wherein the second resulting symbol ordinate is an additive inverse of the initial symbol ordinate and the second resulting symbol abscissa has a same value of the initial symbol abscissa;
• means for translating the second resulting constellation to an up direction of the initial constellation to produce an up flipped constellation comprising up flipped symbols defined by an up flipped symbol abscissa and an up flipped symbol ordinate
• means for applying a central axis symmetry to the initial constellation to generate a third resulting constellation comprising third resulting symbol abscissa and a third resulting symbol ordinate;
• and
• means for translating the third resulting constellation to a left-up direction of the initial constellation to produce a left-up flipped constellation comprising left-up flipped symbols defined by a left-up flipped symbol abscissa and a left-up flipped symbol ordinate.