Dual Carrier Modulation

Abstract

An encoder arranged to encode a data symbol for transmission by means of two carrier signals in accordance with an encoding scheme having the properties that: for a first carrier signal, a plurality of data symbols are mapped to a single modulation point in a constellation of modulation points; and for a second carrier signal, said plurality of data symbols are each mapped to a different modulation point in the constellation of modulation points.

1 . An encoder arranged to encode a data symbol for transmission by means of two carrier signals in accordance with an encoding scheme having the properties that:
 for a first carrier signal, a plurality of data symbols are mapped to a single modulation point in a constellation of modulation points; and   for a second carrier signal, said plurality of data symbols are each mapped to a different modulation point in the constellation of modulation points.   
     
     
         2 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of the constellations shown in any of  FIGS. 7 to 11 . 
     
     
         3 . The encoder as claimed in  claim 2 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations that are unitary transforms of the constellations shown in any of  FIGS. 7 to 11 . 
     
     
         4 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations that are a rotation through a multiple of 90 degrees of the constellations shown in  FIGS. 7 to 11 . 
     
     
         5 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations that are a reflection in either the in-phase or quadrature axis of the constellations shown in  FIGS. 7 to 11 . 
     
     
         6 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations arranged as shown in  FIGS. 7 to 11  but with the real part of each C1 data word exchanged with the imaginary part of the corresponding C2 data word. 
     
     
         7 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations arranged as shown in  FIGS. 7 to 11  but with the real part of each C2 data word exchanged with the imaginary part of the corresponding C1 data word. 
     
     
         8 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations arranged as shown in  FIGS. 7 to 11  but with each C1 data word exchanged with the corresponding C2 data word. 
     
     
         9 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points by means of constellations arranged as shown in  FIGS. 7 to 11  but with each C1 data word exchanged with the corresponding C2 data word. 
     
     
         10 . The encoder as claimed in  claim 1 , wherein the encoder is arranged to encode a signal for transmission in accordance with an encoding scheme in which data symbols are mapped to a modulation point in the constellation of modulation points yby means of constellations that are arranged as shown in  FIGS. 7 to 11  but with different bit combinations contained in one more of a C1 data word and/or a C2 data word.