Hardware-efficient demodulator for CDMA adaptive antenna array systems

Abstract

In the hardware-efficient demodulator for a CDMA adaptive antenna array mechanism of a mobile radio communication system, a correlators bank receives digital baseband signals received through an antenna array of a base station and computes correlation values with a local code sequence. A beamformer receives the digital baseband signals and the correlation values from the correlators bank and calculates beamforming weight vectors. A searchers bank receives the digital baseband signals and calculates an initial acquisition and reliable timing information for a multipath search by a common work with the beamformer, which uses a beamforming algorithm. A beamforming complex multiplier for a finger performs a complex multiplication for the beamforming weight vectors and the digital baseband signals, and sums up them. A finger bank receives output signals from the beamforming complex multiplier, executes a code tracking for an alignment between a transmission code and a phase by each multipath on the basis of the multipath search timing information to then provide the timing information of the multipath tracking to the correlators bank, and outputs signals of dispreaded multipath through a time alignment based on each path. A multipath combiner performs a multipath combination for the output signals of the finger bank on a time base and outputting it.

1. A demodulator for a CDMA adaptive antenna array system comprising:
 correlators bank means for receiving digital baseband signals of a chip-level received through an antenna array of a base station and computing correlation values with a local code sequence;  
 beamforming means for receiving the digital baseband signals and calculating beamforming weight vectors on the basis of the correlation values of said correlators bank means;  
 beamforming complex multiplying means for a multipath searcher, for receiving the digital baseband signals, performing a complex multiplication for the beamforming weight vector from said beamforming means and the respective signals, and summing up them;  
 searchers bank means for receiving output signals from said beamforming complex multiplying means provided for the multipath searcher, executing a multipath search to output multipath search timing information, and inputting and outputting data from/to said beamforming means for a selection diversity;  
 beamforming complex multiplying means for a finger, for receiving the digital baseband signals, performing the complex multiplication for the beamforming weight vector from said beamforming means and the respective signals, and summing up them;  
 finger bank means for receiving output signals from said beamforming complex multiplying means provided for the finger, executing a multipath tracking on the basis of the multipath search timing information of said searchers bank means, and supplying traced multipath tracking timing information to said correlators bank means; and  
 multipath-combining means for receiving output signals from said finger bank means, performing a multipath combination for the output signals on a time base, and outputting it.  
 
     
     
       2. The demodulator of  claim 1 , wherein said beamforming means prestores the beamforming weight vectors corresponding to each subsector within one sector of a cell therein; receives correlation results with the local code sequence of a subsector set for each beamforming weight vector from said searchers bank means and searches for the subsector index corresponding to the largest correlation value; searches for initial acquisition or the timing information for the multipath search from correlation values with a signal concerned with the subsector index to feedback it to said searchers bank means; and generates the beamforming weight vectors by the selection diversity in which the beamforming weight vector of one set among the beamforming weight vectors corresponding to each subsector is selected and used. 
     
     
       3. The demodulator of  claim 1 , wherein said beamforming means generates the beamforming weight vectors for said searchers bank means and the beamforming weight vectors for the finger bank by using the digital baseband signals, input data from said searchers bank means and input data from said correlators bank means and sends the generated beamforming weight vectors to said beamforming complex multiplying means for said searchers bank means and said beamforming complex multiplying means for the finger. 
     
     
       4. The demodulator of  claim 1 , wherein said searchers bank means determines the timing information corresponding to the correlation value which is over a predetermined threshold among all the correlation values, as timing information concerned with the initial acquisition or the multipath search, by using the beamforming weight vectors provided from said beamforming means. 
     
     
       5. The demodulator of  claim 1 , wherein said correlators bank means generates the correlation values obtained by a calculation result accumulated within several code chip period on the basis of the multipath tracking timing information provided from said finger bank means, and sends the values to said beamforming means, so that it is no need to store several correlation values in said searchers bank means or said finger bank means. 
     
     
       6. A demodulator for a CDMA adaptive antenna array system comprising:
 correlators bank means for receiving digital baseband signals received through an antenna array of a base station and computing correlation values with a local code sequence;  
 beamforming means for receiving the digital baseband signals and calculating beamforming weight vectors on the basis of the correlation values of said correlators bank means;  
 searchers bank means for receiving the digital baseband signals and calculating an initial acquisition and reliable timing information for a multipath search, by a common work with said beamforming means which uses a beamforming algorithm;  
 finger bank means for receiving the digital baseband signals, executing a code tracking for an alignment between a transmission code and a phase by each multipath on the basis of the multipath search timing information by the common work with said beamforming means, and providing the multipath tracking timing information to said correlators bank means;  
 complex multiplying means for complex-multiplying the digital baseband input signals of dispreaded symbol-level outputted from said finger bank means, by the beamforming weight vectors provided from said beamforming means, respectively, and then performing its summing up; and  
 multipath combining means for performing a multipath combination of the output signals provided from said complex multiplying means, on a time base, and outputting it.  
 
     
     
       7. A demodulator for a CDMA adaptive antenna array system comprising:
 correlators bank means for receiving digital baseband signals received through an antenna array of a base station and computing correlation values with a local code sequence;  
 beamforming means for receiving the digital baseband signals and the correlation values from said correlators bank means, and computing beamforming weight vectors;  
 searchers bank means for receiving the digital baseband signals and calculating an initial acquisition and reliable timing information for a multipath search, by a common work with said beamforming means which uses a beamforming algorithm;  
 beamforming complex multiplying means for a finger, for performing a complex multiplication for the beamforming weight vectors and the digital baseband signals, and summing up them;  
 finger bank means for receiving output signals from said beamforming complex multiplying means, executing a code tracking for an alignment between a transmission code and a phase by each multipath on the basis of the multipath search timing information to then provide the traced multipath tracking timing information to said correlators bank means, and outputting signals of dispreaded multipath through a time alignment based on each path; and  
 multipath combining means for performing a multipath combination of output signals provided from said finger bank means on a time base, and outputting it.  
 
     
     
       8. A demodulator comprising:
   at least one multiplier for determining a multiplier output signal by multiplying a digital baseband signal with a beamforming weight vector;        at least one searcher for determining multipath timing information based on said multiplier output signal; and        at least one finger for tracking said multipath timing information and providing a finger output signal.     
     
     
       9. The demodulator as claimed in  claim 8 , further comprising at least one beamformer for determining said beamforming weight vectors. 
     
     
       10. The demodulator as claimed in  claim 8 , further comprising a multipath- combiner for receiving at least one finger output signal and combining said output signals in a time base.   
     
     
       11. A demodulator comprising:
   at least one searcher for determining multipath timing information signal from a digital baseband signal, the at least one searcher receiving an output signal from a beamforming multiplier;        at least one finger for determining at least one dispread traffic signal based on said digital baseband signal and said multipath timing information; and        at least one multiplier for determining a multiplier output signal by multiplying said dispread traffic signal from said at least one finger with a beamforming weight factor.     
     
     
       12. A demodulator for a CDMA adaptive antenna array system for demodulating digital baseband signals, the demodulator comprising:
   a beamformer for receiving the digital baseband signals and calculating beamforming weight vectors;        a beamforming multiplier for receiving the digital baseband signal and multiplying and summing the digital baseband signal and the beamforming weight vectors to obtain an output signal;        a searcher bank for receiving the output signal from the beamforming multiplier and outputting multipath search timing information; and        a finger bank for receiving the multipath search timing information and tracking the multipath timing information.     
     
     
       13. A demodulator for a CDMA adaptive antenna array system for demodulating digital baseband signals, the demodulator comprising:
   a beamformer for receiving the digital baseband signals and calculating beamforming weight vectors;        a searcher bank for receiving the digital baseband signal and working with the beamformer to output timing information;        a finger bank for receiving the multipath search timing information and tracking the timing information to output dispread traffic signals; and        a multiplier for receiving the dispread traffic signal and multiplying and summing the digital baseband signal and the beamforming weight vectors to obtain an output signal.     
     
     
       14. A demodulator for a CDMA adaptive antenna array system comprising:
   a correlator bank for reciting digital baseband signals of a chip - level received through an antenna array of a base station and computing correlation values with a local code sequence;        a beamformer for receiving the digital baseband signals and calculating beamforming weight vectors on the basis of the correlation values of said correlator bank;        a beamforming complex multiplier for a multipath searcher, for receiving the digital baseband signals, performing a complex multiplication for the beamforming weight vector from said beamformer and the respective signals, and summing up them;        a searcher bank for receiving output signals from said beamforming complex multiplier provided for the multipath searcher, executing a multipath search to output multipath search timing information, and inputting and outputting data from/to said beamformer for a selection diversity;        a beamforming complex multiplier for a finger, for receiving the digital baseband signals, performing the complex multiplication for the beamforming weight vector from said beamformer and the respective signals, and summing up them;        a finger bank for receiving output signals from said beamforming complex multiplier provided for the finger, executing a multipath tracking on the basis of the multipath search timing information of said searcher bank, and supplying traced multipath tracking timing information to said correlator bank; and        a multipath - combiner for receiving output signals from said finger bank, performing a multipath combination for the output signals on a time base, and outputting it.     
     
     
       15. The demodulator of  claim 14 , wherein said beamformer prestores the beamforming weight vectors corresponding to each subsector within one sector of a cell therein; receives correlation results with the local code sequence of a subsector set for each beamforming weight vector from said searcher bank and searches from the subsector index corresponding to the largest correlation value; searches for initial acquisition or the timing information for the multipath search for correlation values with a signal concerned with the subsector index to feedback it to said searcher bank; and generates the beamforming weight vectors by the selection diversity in which the beamforming weight vector of one set among the beamforming weight vectors corresponding to each subsector is selected and used. 
     
     
       16. The demodulator of  claim 14 , wherein said beamformer generates the beamforming weight vectors for said searcher bank and the beamforming weight vectors for the finger bank by using the digital baseband signals, input data from said searcher bank and input data from said correlator bank and sends the generated beamforming weight vectors to said beamforming complex multiplier for said searcher bank and said beamforming complex multiplier for the finger. 
     
     
       17. The demodulator of  claim 14 , wherein said searcher bank determines the timing information corresponding to the correlation value which is over a predetermined threshold among all the correlation values, as timing information concerned with the initial acquisition or multipath search, by using the beamforming weight vectors provided from said beamformer. 
     
     
       18. The demodulator of  claim 14 , wherein said correlator bank generates the correlation values obtained by a calculation result accumulated within several code chip period on the basis of the multipath tracking timing information provided from said finger bank, and sends the values to said beamformer, so that it is no need to store several correlation values in said searcher bank or said finger bank. 
     
     
       19. A demodulator for CDMA adaptive antenna array system comprising:
   a correlator bank for receiving digital baseband signals received through an antenna array of a base station and computing correlation values with a local code sequence;        a beamformer for receiving the digital baseband signals and calculating beamforming weight vectors on the basis of the correlation values of said correlator bank;        a searcher bank for receiving the digital baseband signals and calculating an initial acquisition and reliable timing information for a multipath search, by a common work with said beamformer which uses a beamforming algorithm;        a finger bank for receiving the digital baseband signals, executing a code tracking for an alignment between a transmission code and a phase by each multipath on the basis of the multipath search timing information by the common work with said beamformer, and providing the multipath tracking timing information to said correlator bank;        a complex multiplier for complex - multiplying the digital baseband input signals dispreaded symbol - level outputted from said finger bank, by the beamforming weight vectors provided from said beamformer, respectively, and then performing its summing - up; and        a multipath combiner for performing a multipath combination of the output signals provided from said complex multiplier, on a time bases, and outputting it.     
     
     
       20. A demodulator for a CDMA adaptive antenna array system comprising:
   a correlator bank for receiving digital baseband signals received through an antenna array of a base station and computing correlation values with a local code sequence;        a beamformer for receiving the digital baseband signals and the correlation values from said correlator bank, and computing beamforming weight vectors;        a searcher bank for receiving the digital baseband signals and calculating an initial acquisition and reliable timing information for a multipath search, by a common work with said beamformer which uses a beamforming algorithm;        a beamforming complex multiplier for a finger, for performing a complex multiplication for the beamforming weight vectors and the digital baseband signals, and summing up them;        a finger bank for receiving output signals from said beamforming complex multiplier, executing a code tracking for an alignment between a transmission code and a phase by each multipath on the basis of the multipath search timing information to then provide the traced multipath tracking timing information to said correlator bank, and outputting signals of dispreaded multipath through a time alignment based on each path; and        a multipath combiner for performing a multipath combination of output signals provided from said finger bank on a time base, and outputting it.