Receiver and wireless lan apparatus in which a received signal is correlated to a reference symbol

Abstract

A receiver comprising: an antenna which receives a radio signal including N possible symbols {c 1 (n) , c 2 (n) , c M−1 (n) , c M (n) }, an N correlation units which are provided corresponding to the N possible symbols, respectively, each correlation unit detecting the degree of correlation with the radio signal received by the antenna, and a symbol determination unit which determines the symbol included in the radio signal received by the antenna based on the degree of correlation detected by the N correlation units. The N correlation units detect the degree of correlation between the radio signal received by the antenna and the N possible symbols represented by M chips {α 0 c 1 (n) ,α 0 c 2 (n) +α 1 c 1 (n) , . . . ,α 0 c M−1 (n) +α 1 c M−2 (n) , α 0 c M (n) +α 1 c M−1 (n) }.

1 . A receiver, comprising: 
 an antenna which receives a radio signal including N possible symbols {c 1   (n) , c 2   (n) , . . . c M−1   (n) , c M   (n) }, where n is an integer satisfying the relation 1<n≦N, each symbol represented by M chips, M is an integer equal to or more than 2;    N correlation units corresponding to said N possible symbols, respectively, each correlation unit detecting the degree of correlation with a preceding wave and a one-chip delay wave included in the radio signal received by said antenna; and    a symbol determination unit which determines the symbol included in the radio signal received by said antenna based on the degree of correlation detected by said N correlation units,    wherein said N correlation units detect the degree of correlation between the radio signal received by said antenna and the N possible symbols represented by M chips {α 0 c 1   (n) , α 0 c 2   (n) +α 1 c 1   (n) , . . . , α 0 c M−1   (n) +α 1 c M−2   (n) , α 0 c M−1   (n) }, where n is an integer satisfying the relation 1<n≦N, and α 0  and α 1  are non-zero constants, and    a ratio between said α 0  and α 1  is a ratio between a channel impulse response coefficient of a preceding wave and a channel impulse response coefficient of a one-chip delay wave each included in the radio signal received by said antenna.    
   
   
       2 . The receiver according to  claim 1 , wherein a ratio between said α 0  and α 1  is a ratio between a channel impulse response coefficient of a preceding wave and that of a one-chip delay wave each included in the radio signal received by said antenna.  
   
   
       3 . The receiver according to  claim 1 , further comprising a delay removal unit configured to remove a k-chip delay wave, where k is a constant equal to or more than 2, from the radio signal, the delay removal unit having a plurality of outputs, 
 wherein the outputs of said delay removal unit are inputted to said N correlation units, respectively.    
   
   
       4 . The receiver according to  claim 3 , wherein said delay removal unit removes said k-chip delay wave from the radio signal based on the preceding wave included in the radio signal received by said antenna.  
   
   
       5 . The receiver according to  claim 3 , wherein said delay removal unit removes said k-chip delay wave from the radio signal based on the one-chip delay wave included in the radio signal received by said antenna.  
   
   
       6 . The receiver according to  claim 1 , further comprising a level comparison unit configured to compare a signal level of the preceding wave with a signal level of the one-chip delay wave each included in the radio signal received by said antenna, 
 wherein said delay removal unit removes the k-chip delay wave by using the preceding wave or the one-chip delay wave with larger signal level based on a comparison result of said level comparison unit.    
   
   
       7 . The receiver according to  claim 1 , further comprising: 
 an amplifier which amplifies the wireless signal received by said antenna;    a frequency converter which converts the output signal of said amplifier to a low-frequency signal; and    an A/D converter which converts the output signal of said frequency converter to a digital signal,    wherein said N correlation units detect the degree of correlation based on the digital signal.    
   
   
       8 . The receiver according to  claim 1 , wherein N correlation units detect the degree of correlation with respect to a wireless signal of CCK (Complementary Code Keying) modulation scheme or M-ary modulation scheme received by said antenna.  
   
   
       9 . A receiver, comprising: 
 an antenna which receives a radio signal including N possible symbols {c 1   (n) , c 2   (n) , . . . c M−1   (n) , c M   (n) }, where n is an integer satisfying the relation 1<n≦N, each symbol represented by M chips, M is an integer equal to or more than 2;    N correlation units corresponding to said N possible symbols, respectively, each correlation unit detecting the degree of correlation with a preceding wave and a k-chip delay wave included in the radio signal received by said antenna; and    a symbol determination unit which determines the symbol included in the radio signal received by said antenna, based on the degree of correlation detected by said N correlation units,    wherein said N correlation units detect the degree of correlation between the radio signal received by said antenna and N possible symbols      α 0 c 1   (n) ,  α 0 c 2   (n) +α 1 c 1   (n) ,  α 0 c 3   (n) +α 1 c 2   (n) +α 2 c 1   (n) ,  :  :  α 0 c M−1   (n) +α 1 c M−2   (n) +α 2 c M−3   (n) +, . . . ,+α M−2 c 1   (n) ,  α 0 c M   (n) +α 1 c M−1   (n) +α 2 c M−2   (n) +, . . . ,+α M−2 c 2   (n) +α M−1 c 1   (n)      each symbol represented by M chips, where n is an integer satisfying the relation 1<n≦N, and α 0  and α 1  are non-zero constants, α 2 , . . . , α M−1  are constants.    
   
   
       10 . The receiver according to  claim 9 , wherein a ratio between said α 0  and α 1  is a ratio between a channel impulse response coefficient of a preceding wave and that of a one-chip delay wave each included in the radio signal received by said antenna.  
   
   
       11 . The receiver according to  claim 9 , comprising a delay removal unit configured to remove a k-chip delay wave, where k is a constant equal to or more than 2, 
 wherein the outputs of said delay removal unit are inputted to said N correlation units, respectively.    
   
   
       12 . The receiver according to  claim 11 , wherein said delay removal unit removes said k-chip delay wave based on the preceding wave included in the radio signal received by said antenna.  
   
   
       13 . The receiver according to  claim 11 , wherein said delay removal unit removes said k-chip delay wave based on the one-chip delay wave included in the radio signal received by said antenna.  
   
   
       14 . The receiver according to  claim 11 , further comprising a level comparison unit configured to compare a signal level of the preceding wave with a signal level of the one-chip delay wave each included in the radio signal received by said antenna, 
 wherein said delay removal unit removes the k-chip delay wave by using the preceding wave or the one-chip delay wave with larger signal level based on a comparison result of said level comparison unit.    
   
   
       15 . The receiver according to  claim 9 , further comprising: 
 an amplifier which amplifies the wireless signal received by said antenna;    a frequency converter which converts the output signal of said amplifier to a low-frequency signal; and    an A/D converter which converts the output signal of said frequency converter to a digital signal,    wherein said N correlation units detect the degree of correlation based on the digital signal.    
   
   
       16 . The receiver according to  claim 9 , wherein N correlation units detect the degree of correlation with respect to a wireless signal of CCK (Complementary Code Keying) modulation scheme or M-ary modulation scheme received by said antenna.  
   
   
       17 . A wireless LAN apparatus, comprising: 
 an antenna which receives a radio signal including N possible symbols c 1   (n) , c 2   (n) , . . . c M−1   (n) , c M   (n) }, where n is an integer satisfying the relation 1<n≦N, each symbol represented by M chips, M is an integer equal to or more than 2;    N correlation units corresponding to said N possible symbols, respectively, each correlation unit detecting the degree of correlation with a preceding wave and a one-chip delay wave included in the radio signal received by said antenna;    a symbol determination unit which determines the symbol included in the radio signal received by said antenna, based on the degree of correlation detected by said N correlation units; and    a data processing unit configured to perform decoding based on the symbol determined by said symbol determination unit,    wherein said N correlation units detect the degree of correlation between the radio signal received by said antenna and the N possible symbols represented by M chips {α 0 c 1   (n) , α 0 c 2   (n) +α 1 c 1   (n) , . . . , α 0 c M−1   (n) +α 1 c M−2   (n) , α 0 c M   (n) +αc M−1   (n) }, where n is an integer satisfying the relation 1<n≦N, and α 0  and α 1  are non-zero constants.    
   
   
       18 . The wireless LAN apparatus according to  claim 17 , wherein a ratio between said α 0  and α 1  is a ratio between a channel impulse response coefficient of a preceding wave and that of a one-chip delay wave each included in the radio signal received by said antenna.  
   
   
       19 . The wireless LAN apparatus according to  claim 17 , comprising a delay removal unit configured to remove a k-chip delay wave, where k is a constant equal to or more than 2, 
 wherein the outputs of said delay removal unit are inputted to said N correlation units, respectively.    
   
   
       20 . A receiving method, comprising: 
 receiving a radio signal including N possible symbols {c 1   (n) , c 2   (n) , . . . c M−1   (n) , c M   (n) }, where n is an integer satisfying the relation 1<n≦N, each symbol represented by M chips, M is an integer equal to or more than 2, by an antenna;    detecting the degree of correlation between a preceding wave and a one-chip delay wave included in the radio signal received by said antenna and the N possible symbols represented by M chips {α 0 c 1   (n) , α 0 c 2   (n) +α 1 c 1   (n) , . . . , α 0 c M−1   (n) +α 1 c M−2   (n) , α 0 c M   (n) +α 1 c M−1   (n) }, where n is an integer satisfying the relation 1<n≦N, and α 0  and α 1  are non-zero constants; and    determining the symbol included in the radio signal received by said antenna.    
   
   
       21 . An apparatus, comprising: 
 N correlation units corresponding to said N possible symbols {c 1   (n) , c 2   (n) , . . . c M−1   (n) , c M   (n) }, where n is an integer satisfying the relation 1<n≦N, each symbol represented by M chips, M is an integer equal to or more than 2, respectively, each correlation unit detecting the degree of correlation with a preceding wave and a one-chip delay wave included in a radio signal including N possible symbols; and    a symbol determination unit which determines the symbol included in the radio signal based on the degree of correlation detected by said N correlation units,    wherein said N correlation units detect the degree of correlation between the radio signal and the N possible symbols represented by M chips {α 0 c 1   (n) , α 0 c 2   (n) +α 1 c 1   (n) , . . . , α 0 c M−1   (n) +α 1 c M−2   (n) , α 0 c M   (n) +α 1 c M−1   (n) }, where n is an integer satisfying the relation 1<n≦N, and α 0  and α 1  are non-zero constants.