AN ADAPTIVE KALMAN FILTER EXCISOR FOR SUPPRESSING NARROWBAND INTERFERENCE

Authors
  1. Kozminchuk, B.W.
Corporate Authors
Defence Research Establishment Ottawa, Ottawa ONT (CAN)
Abstract
Several reports have been written by the author which characterize the performance of a Kalman filtering technique to suppress narrowband interference from direct sequence spread spectrum communications systems in a non-adaptive context, i.e., when the user has some a priori knowledge of the interference characteristics. The report expands on this technique by presenting an adaptive scheme which is useful for the situation when the interference characteristics are unknown. In this context, the Kalman filter must "learn" to achieve optimal performance through the adjustment of one of its parameters. The criterion for optimality is the minimization of the mean-squared error at the output of the canceller, where this error consists of spread spectrum signal, noise and residual interference. The reasonable assumption is made that m,inimizing the mean of this squared error with respect to the appropriate Kalman filter parameter is equivalent to minimizing the mean squared value of the residual interference. Examples of the dynamic behaviour of the adaptive interference suppressor are presented for narrowband Gaussian noise interference with bandwidths ranging from 1 to 5% of the chip rate.
Keywords
PHASE LOCKED LOOP
Report Number
DREO-TN-93-20 — Technical Note
Date of publication
01 Dec 1993
Number of Pages
46
DSTKIM No
94-04487
CANDIS No
139024
Format(s):
Hardcopy

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