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S. Nishimura and H. Y. Jiang, “Simplified realization of cascaded adaptive notch filters with complex coefficients,” Proceedings of International Symposium on Circuits and Systems, Vol. 5, pp. 269–272, 1998.

has been cited by the following article:

• TITLE: QPSK DS-CDMA System over Rayleigh Channel with a Randomly-Varying Frequency Narrow-Band Interference: Frequency Tracking Analysis

  AUTHORS: Aloys N. Mvuma

  KEYWORDS: Code-Division Multiple Access (CDMA), Quadriphase Shift Keying (QPSK), Complex Adaptive IIR Notch Filter, Narrow-Band Interference (NBI), Frequency Tracking MSE

  JOURNAL NAME: Wireless Sensor Network, Vol.2 No.3, April 12, 2010

  ABSTRACT: This paper analyses frequency tracking characteristics of a complex-coefficient adaptive infinite-impulse response (IIR) notch filter used for suppression of narrow-band interference (NBI) with a randomly-varying frequency in a quadriphase shift keying (QPSK) modulated direct-sequence code-division multiple-access (DS-CDMA) communication system. The QPSK DS-CDMA signals are transmitted over a frequency non-selective Rayleigh fading channel. The analysis is based on a first-order real-coefficient difference equation with respect to steady-state instantaneous frequency tracking error from which a closed-form expression that relates frequency tracking mean square error (MSE) with number of DS-CDMA active users and NBI power is obtained. Closed-form expressions for optimum notch bandwidth coefficient and step size constant that minimize the frequency tracking MSE are also derived. Computer simulations are included to substantiate the accuracy of the analyses.