Method and apparatus for generating equalizer filter tap coefficients

Abstract

A method and apparatus generating an error signal and an update vector signal used to generate filter tap coefficients for an equalizer filter residing in an equalizer. The equalizer filter outputs an equalized signal in response to receiving a sample data stream. The error signal is generated by down-sampling the equalized signal, subtracting the equalized signal from a reference signal, and filtering and down-sampling the resulting signal. Simultaneously, the update vector signal is generated by converting scalar samples of the sample data stream to a data vector signal and descrambling, filtering, and down-sampling the data vector signal. A tap coefficients generator is used to generate the filter tap coefficients for updating the equalizer filter based on the error signal and the update vector signal.

1 . An equalizer comprising:
 at least one equalizer filter for processing at least one input sample data stream with filter coefficients from at least one antenna to generate at least one equalized signal;   a first multiplier configured to multiply a scrambling code conjugate signal with the at least one equalized signal to generate at least one descrambled equalized signal;   an adder configured to generate at least one error signal by subtracting the at least one descrambled equalized signal from a reference signal;   an error filter configured to filter the at least one error signal to generate at least one filtered error signal;   a tap coefficients generator configured to generate tap coefficients based on the at least one filtered error signal for updating the filter coefficients of the at least one equalizer filter; and   a first down-sampler inserted between the at least one equalizer filter and the first multiplier, the first down-sampler configured to down-sampling the at least one equalized signal, wherein the at least one equalized signal is down-sampled by the first down-sampler by a factor of over-sampling on a condition that the at least one sample data stream undergoes over-sampling.   
   
   
       2 . The equalizer of  claim 1  further comprising:
 a second down-sampler inserted between the error filter and the tap coefficients generator, the second down-sampler configured to down-sampling the at least one filtered error signal at a desired down-sampling rate.   
   
   
       3 . The equalizer of  claim 1  wherein the at least one equalizer filter is a finite impulse response filter. 
   
   
       4 . An equalizer comprising:
 at least one equalizer filter configured to process at least one input sample data stream with filter coefficients from at least one antenna to generate at least one equalized signal;   a first multiplier configured to multiply a scrambling code conjugate signal with the at least one equalized signal to generate at least one descrambled equalized signal;   an adder configured to generate at least one error signal by subtracting the at least one descrambled equalized signal from a reference signal;   an error filter configured to filter the at least one error signal to generate at least one filtered error signal;   a tap coefficients generator configured to generate tap coefficients based on the at least one filtered error signal for updating the filter coefficients of the equalizer filter;   a serial-to-parallel to vector converter configured to convert scalar samples of the at least one sample data stream to at least one data vector signal;   a second multiplier configured to multiply the scrambling code conjugate signal with the at least one data vector signal to generate at least one descrambled data vector signal; and   an error filter vector version unit configured to generate at least one filtered update vector signal based on the at least one descrambled data vector signal, wherein the tap coefficients generated by the tap coefficients generator are also based on the at least one filtered update vector signal.   
   
   
       5 . The equalizer of  claim 4  further comprising:
 a third down-sampler inserted between the serial-to-parallel to vector converter and the second multiplier for down-sampling the at least one data vector signal, wherein if the at least one sample data stream undergoes over-sampling, the at least one data vector signal is down-sampled by the third down-sampler by a factor of over-sampling.   
   
   
       6 . The equalizer of  claim 5  further comprising:
 a fourth down-sampler inserted between the error filter vector version unit and the tap coefficients generator for down-sampling the at least one filtered update vector signal at a desired down-sampling rate.   
   
   
       7 . The equalizer of  claim 1  wherein the tap coefficients generator generates the tap coefficients based on a normalized least mean square algorithm. 
   
   
       8 . An equalizer comprising:
 an equalizer filter for processing at least one input sample data stream with filter coefficients from at least one antenna to generate at least one equalized signal;   a serial-to-parallel to vector converter which converts scalar samples of the at least one sample data stream to a data vector signal;   a first multiplier for multiplying the scrambling code conjugate signal with the at least one data vector signal to generate at least one descrambled data vector signal;   an error filter vector version unit for generating at least one filtered update vector signal based on the at least one descrambled data vector signal; and   a tap coefficients generator for generating tap coefficients based on the at least one filtered update vector signal for updating the filter coefficients of the at least one equalizer filter.   
   
   
       9 . The equalizer of  claim 8  further comprising:
 a first down-sampler inserted between the serial-to-parallel to vector converter and the first multiplier for down-sampling the at least one data vector signal, wherein if the at least one sample data stream undergoes over-sampling, the at least one data vector signal is down-sampled by the first down-sampler by a factor of over-sampling.   
   
   
       10 . The equalizer of  claim 9  further comprising:
 a second down-sampler inserted between the error filter vector version unit and the tap coefficients generator for down-sampling the at least one filtered update vector signal at a desired down-sampling rate.   
   
   
       11 . The equalizer of  claim 8  wherein the equalizer filter is a finite impulse response filter. 
   
   
       12 . The equalizer of  claim 8  further comprising:
 a second multiplier for multiplying a scrambling code conjugate signal with the at least one equalized signal to generate at least one descrambled equalized signal;   an adder for generating at least one equalizer error signal by subtracting the at least one descrambled equalized signal from a reference signal; and   an equalized signal error filter for filtering the at least one equalizer error signal to generate at least one filtered equalizer error signal, wherein the tap coefficients generated by the tap coefficients generator are also based on the at least one filtered equalizer error signal.   
   
   
       13 . The equalizer of  claim 10  further comprising:
 a second multiplier for multiplying a scrambling code conjugate signal with the at least one equalized signal to generate a descrambled equalized signal;   an adder for generating at least one equalizer error signal by subtracting the at least one descrambled equalized signal from a reference signal; and   an equalized signal error filter for filtering the at least one equalizer error signal to generate at least one filtered equalizer error signal, wherein the tap coefficients generated by the tap coefficients generator are also based on the at least one filtered equalizer error signal.   
   
   
       14 . The equalizer of  claim 10  further comprising:
 a third down-sampler inserted between the at least one equalizer filter and the second multiplier for down-sampling the equalized signal, wherein if the at least one sample data stream undergoes over-sampling, the at least one equalized signal is down-sampled by the third down-sampler by a factor of over-sampling.   
   
   
       15 . The equalizer of  claim 14  further comprising:
 a fourth down-sampler inserted between the second error filter and the tap coefficients generator for down-sampling the at least one filtered equalizer error signal at the desired down-sampling rate.   
   
   
       16 . The equalizer of  claim 8  wherein the tap coefficients generator generates the tap coefficients based on a normalized least mean square algorithm.