Transmission/reception unit with bidirectional equalization

Abstract

The present invention refers to a transmission/reception unit that exchanges data with a remote unit by means of a channel using distributed modulation/demodulation treatment means. The transmission/reception unit includes equalization means ( 23 ) to equalize a first signal received from said remote unit and predistortion means to predistort a second signal transmitted to said remote unit. According to the invention, the unit is characterized in that the modulation/demodulation treatment means operate in a non-linear way and the unit includes means ( 230 ) to store information that is representative of a non-linear distortion of said modulation/demodulation treatment means and which defines a non-linear reference, and means ( 233 ) to adjust coefficients (CO) in the equalization means ( 23 ) according to the signal received from the remote unit and said representative information, the mentioned adjusted coefficients being transmitted to said predistortion means.

1 . Data transmission/reception unit to exchange data with a remote unit through a channel using means for modulation/demodulation treatment distributed between said data transmission/reception unit and said remote unit, said transmission/reception unit including equalization means ( 23 ) to equalize a first signal received from said remote unit and predistortion means ( 13 ;  13   a ,  13   b ) to predistort a second signal transmitted to said remote unit, 
 characterized in that (a)—the means for modulation/demodulation treatment operate according to a non-linear mode and (b)—the unit includes    (b1)—means ( 230 ,  231 ; l) to store information which is representative of a non-linear distortion of said modulation/demodulation treatment means and which defines a non-linear reference, and    (b2)—means ( 233 ; COR, EQU) to adjust coefficients (CO) in the equalization means ( 23 ) according to the signal received from the remote unit and said representative information, said adjusted coefficients being transmitted to said predistortion means ( 13 ;  13   a ,  13   b ).    
     
     
         2 . Transmission/reception unit according to    claim 1   , characterized in that the data transmission/reception unit exchanges data with said remote unit using a duplex mode by time division, and that said adjusted coefficients (CO) are used in the equalization means to equalize said first signal during a reception time interval and are transmitted to said predistortion means to predistort said second signal during the following transmission time interval.  
     
     
         3 . Transmission/reception unit according to    claim 1   , characterized in that the adjustment means are calculation means ( 233 ) which minimize an error signal (ES) in the equalization means ( 233 ) according to, on the one hand, said signal received from the remote unit and, on the other hand, said representative information.  
     
     
         4 . Transmission/reception unit according to    claim 2   , characterized in that the means for non-linear modulation/demodulation treatment are frequency modulation/demodulation treatment means.  
     
     
         5 . Transmission/reception unit according to    claim 3   , characterized in that said unit is a base station of a radio communications system with the mobile phones according to the DECT standard.  
     
     
         6 . Transmission/reception unit according to    claim 1   , characterized in that the adjustment means include: 
 means (A/D) to sample said first signal received from the remote unit to a higher frequency than a frecuency of logic symbols associated to the signal received and to define sample sets ({φ(k, T)}), each one defined by a sample phase respectively,    means (COR) to correlate said representative information ({l}) to each one of the sample sets ({φ(k, T)}) of the signal received from the remote unit, to define the a priori optimum sample set ({φ(k, T)}),    means to select a sample set between said a priori optimum sample set ({φ(k, T)}) and some of said sample sets ({φ(K−2, T)}, {φ(K−1, T)}, {φ(K+1, T)} and {φ(K+2, T)}) defined by sample phases near to the sample phase of said a priori optimum sample set, the selected set being the set producing the smallest equalization error signal with respect to a logic symbol sequence (TS), and    calculation means to minimize an error signal in the equalization means, according, on the one hand, to said signal received from the remote unit when it is sampled with the sample phase of the selected sample set and, on the other, to said logic symbol sequence (TS).    
     
     
         7 . Transmission/reception unit according to    claim 5   , characterized in that the means for non-linear modulation/demodulation treatment are means for frequency modulation/demodulation treatment.  
     
     
         8 . Transmission/reception unit according to    claim 6   , characterized in that said unit is a base station of a radio communications system with the mobile phones according to the DECT standard.