Systems and methods for multicarrier modulation using multi-tap frequency-domain equalizer and decision feedback

Abstract

Through the use of feedback in determining frequency domain equalization, intersymbol interference can be reduced. Specifically, the determined constellation point closest to the determined received point can be fed back to aid in determining one or more other closest constellation points.

What is claimed:  
     
         1 . An intersymbol interference reduction system comprising: 
 a frequency domain equalizer; and    a constellation decoder, the frequency domain equalizer determining at least one received point based at least on at least one previously determined constellation point.    
     
     
         2 . The system of  claim 1 +wherein the at least one previously determined constellation point is feedback which can be one or more of forward looking feedback and backward looking feedback.  
     
     
         3 . The system of  claim 1 , wherein a plurality of decisions about the value of s i     1     m     1    obtained by quantizing {circumflex over (s i     1     m     1   )} to the nearest constellation point are used in determining the at least one received point.  
     
     
         4 . The system of  claim 1 , wherein the intersymbol interference reduction system is used to reduce intersymbol interference in a multicarrier communication environment.  
     
     
         5 . The system of  claim 1 , wherein the intersymbol interference reduction system is incorporated into a transceiver.  
     
     
         6 . A method for reducing intersymbol interference reduction comprising: 
 determining at least one constellation point; and    determining at least one received point based at least on at least one previously determined constellation point.    
     
     
         7 . The method of  claim 6 , wherein the at least one previously determined constellation point is feedback which can be one or more of forward looking feedback and backward looking feedback.  
     
     
         8 . The method of  claim 6 , wherein a plurality of decisions about the value of s i     1     m     1    obtained by quantizing {circumflex over (s i     1     m     1   )} to the nearest constellation point are used in determining the at least one received point.  
     
     
         9 . The method of  claim 6 , wherein the intersymbol interference reduction method is used to reduce intersymbol interference in a multicarrier communication environment.  
     
     
         10 . The method of  claim 6 , wherein the intersymbol interference reduction method is incorporated into a transceiver.  
     
     
         11 . An intersymbol interference reduction system comprising: 
 means for determining at least one constellation point, and    means for determining at least one received point based at least on at least one previously determined constellation point.    
     
     
         12 . The system of  claim 11 , wherein the at least one previously determined constellation point is feedback which can be one or more of forward looking feedback and backward looking feedback.  
     
     
         13 . The system of  claim 11 , wherein a plurality of decisions about the value of s i     1     m     1    obtained by quantizing {circumflex over (s i     1     m     1   )} to the nearest constellation point are used in determining the at least one received point.  
     
     
         14 . The system of  claim 11 , wherein the intersymbol interference reduction method is used to reduce intersymbol interference in a multicarrier communication environment.  
     
     
         15 . The system of  claim 11 , wherein the intersymbol interference reduction method is incorporated into a transceiver.  
     
     
         16 . An information storage media comprising information for reducing intersymbol interference reduction comprising: 
 information that determines at least one constellation point; and    information that determines at least one received point based at least on at least one previously determined constellation point.    
     
     
         17 . The media of  claim 16 , wherein the at least one previously determined constellation point is feedback which can be one or more of forward looking feedback and backward looking feedback.  
     
     
         18 . The media of  claim 16 , wherein a plurality of decisions about the value of s i     1     m     1    obtained by quantizing {circumflex over (s i     1     m     1   )} to the nearest constellation point are used in determining the at least one received point.  
     
     
         19 . The media of  claim 16 , wherein the intersymbol interference reduction method is used to reduce intersymbol interference in a multicarrier communication environment.  
     
     
         20 . The media of  claim 16 , wherein the intersymbol interference reduction method is incorporated into a transceiver.