OFDM modem for transmission of continuous complex numbers

Abstract

The invention enables the transmission of continuous complex numbers using a symbol based transmission scheme such as OFDM. Accordingly, complex numbers are mapped to the constellation map, enabling a fine granularity of constellation points. This scheme may be used, for example, in the transmission of video where the coefficients representing the higher frequency of each of the video components, as well as the quantization error values of the DC and near DC components, or some, possibly non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a symbol.

1 . A wireless video transmitter comprising:
 a symbol mapper to map a first component of a value associated with a video frame to a fine constellation point of a fine transmission symbol plane, wherein the fine transmission symbol plane is defined by groups or constellations of fine symbol points and there is a direct relation between numerical values and spatial proximity of fine symbol points within a given group or constellation of the plane.   
     
     
         2 . The wireless transmitter of  claim 1 , wherein the first component of the value is associated with fine video frame information. 
     
     
         3 . The wireless transmitter according to  claim 2 , wherein fine video frame information is selected from the group consisting of (1) a relatively high order frequency coefficient derived from the video frame, (2) relatively low order bits of a frequency coefficient derived from the video frame, and (3) relatively low order bits of a pixel value of the video frame. 
     
     
         4 . The wireless transmitter according to  claim 1 , wherein the mapper is further adapted to map a second component of the value associated with the video frame to a constellation point of a conventional transmission symbol plane, wherein the transmission symbol plane is defined by transmission symbols which are substantially equally spaced apart. 
     
     
         5 . The wireless transmitter of  claim 4 , wherein the second component of the value is associated with coarse video frame information. 
     
     
         6 . The wireless transmitter according to  claim 4 , wherein the course video frame information is selected from the group consisting of (1) a relatively low order frequency coefficient derived from the video frame, (2) relatively high order bits of a frequency coefficient derived from the video frame, and (3) relatively high order bits of a pixel value of the video frame. 
     
     
         7 . The wireless transmitter of  claim 6 , wherein the second component of the value is a product of a quantization of the value and the first component is a quantization error value of the quantization. 
     
     
         8 . The wireless transmitter of  claim 4 , wherein said mapper is adapted to map components of each of a stream of values associated with one or more video frames. 
     
     
         9 . The wireless transmitter of  claim 8 , wherein said transmitter is an OFDM type transmitter and both fine and coarse transmission symbols are transmitted on the same sub-carrier. 
     
     
         10 . The wireless transmitter of  claim 8 , wherein said transmitter is an OFDM type transmitter and both fine and coarse transmission symbols are transmitted on different sub-carriers. 
     
     
         11 . A wireless video receiver comprising:
 a symbol de-mapper to demap a first received component of a value associated with a video frame using a fine constellation point of a fine transmission symbol plane, wherein the fine transmission symbol plane is defined by groups or constellations of fine symbol points and there is a direct relation between numerical values and spatial proximity of fine symbol points within a given group or constellation of the plane.   
     
     
         12 . The wireless receiver of  claim 11 , wherein the first component of the value is associated with fine video frame information. 
     
     
         13 . The wireless receiver according to  claim 12 , wherein fine video frame information is selected from the group consisting of (1) a relatively high order frequency coefficient derived from the video frame, (2) relatively low order bits of a frequency coefficient derived from the video frame, and (3) relatively low order bits of a pixel value of the video frame. 
     
     
         14 . The wireless receiver according to  claim 11 , wherein the demapper is further adapted to demap a second component of the value associated with the video frame using a constellation point of a conventional transmission symbol plane, wherein the transmission symbol plane is defined by transmission symbols which are substantially equally spaced apart. 
     
     
         15 . The wireless receiver of  claim 14 , wherein the second component of the value is associated with coarse video frame information. 
     
     
         16 . The wireless receiver according to  claim 14 , wherein the course video frame information is selected from the group consisting of (1) a relatively low order frequency coefficient derived from the video frame, (2) relatively high order bits of a frequency coefficient derived from the video frame, and (3) relatively high order bits of a pixel value of the video frame. 
     
     
         17 . The wireless receiver of  claim 16 , wherein the second component of the value is a product of a quantization of the value and the first component is a quantization error value of the quantization. 
     
     
         18 . The wireless receiver of  claim 14 , wherein said demapper is adapted to demap components of each of a stream of values associated with one or more video frames. 
     
     
         19 . The wireless receiver of  claim 18 , wherein said receiver is an OFDM type receiver and both fine and coarse transmission symbols are received on the same sub-carrier. 
     
     
         20 . The wireless receiver of  claim 18 , wherein said receiver is an OFDM type receiver and both fine and coarse transmission symbols are received on different sub-carriers.