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Adaptive IIR Filters for Single Interference Suppression in a BPSK DS CDMA System In Rayleigh Fading Channel


Aloys N. Mvuma

Abstract

In this paper, effect of a single narrow-band interference (NBI) on bit error rate (BER) performance for a binary phase shift  keying  (BPSK)  synchronous  direct-sequence  code-division  multiple  access  (DS  CDMA)  communication system operating  in  a  frequency  nonselective  Rayleigh  fading  channel  is  analyzed.  Second-order  adaptive  infinite  impulse response  (IIR)  notch  filters  with  plain  gradient  algorithm  (GA)  for  suppression  of  NBI  in  the  DS  CDMA system  are proposed. A general closed-form BER expression for the DS CDMA system with NBI suppression second order adaptive IIR  notch  filters  is  derived  based  on  the  standard Gaussian  approximation  (SGA)  method.  BER  expressions  are  then derived  for  the  allpass  filter-based  adaptive  IIR  notch  filter  and  adaptive  IIR  notch  filter  with  constrained  poles  and zeros,  the  two  structures  that  are  commonly  found  in  literature.  It  is  observed  that  both  adaptive  IIR  notch  filter structures  exhibit  comparable  BER  performance.  Extensive  computer  simulation  results  are  presented  to verify  the accuracy and limitations of the analysis.


Journal Identifiers


eISSN: 2619-8789
print ISSN: 1821-536X