Title :
Interpolation lattice filters for narrowband interference cancellation in PN spread spectrum communication systems
Author :
Lee, Jenq-Nan ; Yuan, Jenq-Tay
Author_Institution :
Dept. of Comput. Sci., Nat. Taiwan Ocean Univ., Keelung, Taiwan
Abstract :
Previous work on the adaptive lattice filters for narrowband interference rejection in a direct sequence (DS) spread spectrum communication system has centered around the use of one-sided prediction only. For two-sided interpolation, that is known to achieve better interference rejection than its one-sided counterpart, only the least-mean-squared (LMS) algorithms have been considered thus far in the literature. However, the LMS algorithm has an extremely slow convergence rate. Consequently, the two-sided interpolation filters using the LMS algorithm may not be applicable for suppression of narrowband interference with a time-variant frequency. In this paper, an order-recursive QR-decomposition-based least squares lattice (QRD-LSL) interpolation filter is presented as a solution to the narrowband interference rejection in a DS spread spectrum system. Computer simulation results show that the QRD-LSL interpolation filters can achieve excellent performance in terms of convergence speed as well as SNR improvement for a multiple tone interference with random phase and second-order autoregressive (AR) interference
Keywords :
autoregressive processes; convergence of numerical methods; filtering theory; interference suppression; interpolation; lattice filters; least mean squares methods; pseudonoise codes; radiofrequency interference; spread spectrum communication; AR interference; DS-SS; LMS algorithm; PN spread spectrum communication systems; QRD-LSL interpolation filters; SNR; adaptive lattice filters; computer simulation results; convergence rate; convergence speed; direct sequence spread spectrum communication; interference suppression; least squares lattice interpolation filter; least-mean-squared algorithms; multiple tone interference; narrowband interference cancellation; narrowband interference rejection; order-recursive QR-decomposition; random phase; second-order autoregressive interference; time-variant frequency; two-sided interpolation filters; Adaptive filters; Computer simulation; Frequency; Interference suppression; Interpolation; Lattices; Least squares approximation; Least squares methods; Narrowband; Spread spectrum communication;
Conference_Titel :
Spread Spectrum Techniques and Applications, 2000 IEEE Sixth International Symposium on
Conference_Location :
Parsippany, NJ
Print_ISBN :
0-7803-6560-7
DOI :
10.1109/ISSSTA.2000.878091
