Synchronization timing detecting apparatus, receiving apparatus, and synchronization timing detecting method

Abstract

A synchronization timing detecting apparatus includes a correlation calculator configured to generate a first correlation value by calculating a cross-correlation between an input signal being sampled and a reference signal or an auto-correlation of the sampled input signal, an interpolation processor configured to generate a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal, and a detector to detect a synchronization timing based on the first and the second correlation values.

1 . A synchronization timing detecting apparatus comprising:
 a correlation calculator configured to generate a first correlation value by calculating a cross-correlation between an input signal being sampled and a reference signal or an auto-correlation of the sampled input signal;   an interpolation processor configured to generate a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal; and   a detector to detect a synchronization timing based on the first and the second correlation values.   
     
     
         2 . The synchronization timing detecting apparatus according to  claim 1 , further comprising a selector to select a candidate value having the strongest correlation with the reference signal from the first and the second correlation values,
 wherein the detector detects a synchronization timing by use of the candidate value.   
     
     
         3 . The synchronization timing detecting apparatus according to  claim 1 , further comprising a selector to select a maximum value from the first and the second correlation values,
 wherein the detector detects a synchronizing timing according to whether the maximum value exceeds a predetermined threshold.   
     
     
         4 . The synchronization timing detecting apparatus according to  claim 2 , wherein the number of sampling points of the input signal for a unit of time is same as the number of inputs of the candidate value to the detector for the unit of time. 
     
     
         5 . The synchronization timing detecting apparatus according to  claim 3 , wherein the number of sampling points of the input signal for a unit of time is same as the number of inputs of the maximum value to the detector for the unit of time. 
     
     
         6 . The synchronization timing detecting apparatus according to  claim 1 , wherein
 (a) the input signal is a complex baseband signal,   (b) the correlation calculator comprises:   (i) a first correlator configured to calculate the first correlation value for an In-phase component of the complex baseband signal; and   (ii) a second correlator configured to calculate the first correlation value for an Quadrature component of the complex baseband signal,   (c) the interpolation processor comprises:   (i) a first processor to generate the second correlation value for the In-phase component using the first correlation value of the In-phase component; and   (ii) a second processor to generate the second correlation value for the Quadrature component using the first correlation value of the Quadrature component, and   (d) the detector detects a synchronization timing based on a sum of squares of the first correlation value of the In-phase component and the first correlation value of the Quadrature component and a sum of squares of the second correlation value of the In-phase component and the second correlation value of the Quadrature component.   
     
     
         7 . The synchronization timing detecting apparatus according to  claim 3 , wherein
 (a) the input signal is a complex baseband signal,   (b) the correlation calculator comprises:   (i) a first correlator to calculate the first correlation value for an In-phase component of the complex baseband signal; and   (ii) a second correlator to calculate the first correlation value for a Quadrature component of the complex baseband signal,   (c) the interpolation processor comprises:   (i) a first processor to generate the second correlation value for the In-phase component using the first correlation value of the In-phase component; and   (ii) a second processor to generate the second correlation value for the Quadrature component using the first correlation value of the Quadrature component, and   (d) the selector comprises:   (i) a first sum of squares calculator to calculate a sum of squares of the first correlation value of the In-phase component and the first correlation value of the Quadrature component;   (ii) a second sum of squares calculator to calculate a sum of squares of the second correlation value of the In-phase component and the second correlation value of the Quadrature component; and   (iii) a maximum value selector to select a maximum value from the sum of squares calculated by the first sum of squares calculate and the sum of squares calculated by the second sum of squares calculate to output to the detector.   
     
     
         8 . The synchronization timing detecting apparatus according to  claim 1 , wherein the interpolation processor generates the second correlation value by performing an interpolation process by a sampling function. 
     
     
         9 . A receiving apparatus comprising:
 the synchronization timing detecting apparatus of  claim 1 ;   a sampling unit to sample the input signal to output to the synchronization timing detecting apparatus; and   a demodulator to demodulate the input signal according to a synchronization timing detected by the synchronization timing detecting apparatus.   
     
     
         10 . A receiving apparatus comprising:
 the synchronization timing detecting apparatus of  claim 2 ;   a sampling unit to sample the input signal to output to the synchronization timing detecting apparatus; and a demodulator to demodulate the input signal according to a synchronization timing detected by the synchronization timing detecting apparatus.   
     
     
         11 . A receiving apparatus comprising:
 the synchronization timing detecting apparatus of  claim 3 ;   a sampling unit to sample the input signal to output to the synchronization timing detecting apparatus; and a demodulator to demodulate the input signal according to a synchronization timing detected by the synchronization timing detecting apparatus.   
     
     
         12 . A receiving apparatus comprising:
 the synchronization timing detecting apparatus of  claim 6 ;   a sampling unit to sample the input signal to output to the synchronization timing detecting apparatus; and a demodulator to demodulate the input signal according to a synchronization timing detected by the synchronization timing detecting apparatus.   
     
     
         13 . A receiving apparatus comprising:
 the synchronization timing detecting apparatus of  claim 7 ;   a sampling unit to sample the input signal to output to the synchronization timing detecting apparatus; and a demodulator to demodulate the input signal according to a synchronization timing detected by the synchronization timing detecting apparatus.   
     
     
         14 . A receiving apparatus comprising:
 the synchronization timing detecting apparatus of  claim 8 ;   a sampling unit to sample the input signal to output to the synchronization timing detecting apparatus; and a demodulator to demodulate the input signal according to a synchronization timing detected by the synchronization timing detecting apparatus.   
     
     
         15 . A method of detecting a synchronization timing from an input signal comprising:
 generating a first correlation value by calculating a cross-correlation between the input signal being sampled and the reference signal or an auto-correlation of the sampled input signal;   generating a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal; and   detecting a synchronization timing by use of the first and the second correlation values.   
     
     
         16 . The method according to  claim 15 , wherein the detection of the synchronization timing is performed by selecting a candidate value having the strongest correlation with the reference signal from the first and the second correlation values and determining whether the candidate value exceeds a predetermined threshold. 
     
     
         17 . The method according to  claim 15 , wherein the detection of the synchronization timing is performed by selecting a maximum value from the first and the second correlation values and determining whether the maximum value exceeds a predetermined threshold.