Interference rejection for AMPS using time dependent adaptive filtering and model-based demodulation

In this paper, we explore the combination of the time dependent adaptive filter (TDAF) and the model-based frequency modulation (FM) demodulator for Advanced Mobile Phone System (AMPS) interference rejection. The time dependent adaptive filter, which is blindly adapted using the constant modulus algorithm (CMA), can reject interference by exploiting the cyclostationary and constant envelope properties of the AMPS signal. The model-based FM demodulator uses a parametric method based on forward-backward linear prediction to provide high resolution frequency estimates for distinguishing interference from the desired signal. Examples are provided showing the performance of the combination of the CMA-constrained TDAF and the model-based demodulator in various signal environments. The computer simulation results show that this combination provides better performance for co-channel interference rejection than using only the TDAF or the model-based demodulator.

[1]  B. Porat,et al.  Digital Spectral Analysis with Applications. , 1988 .

[2]  J. H. Reed,et al.  Spectral correlation of AMPS signals and its application to interference rejection , 1994, Proceedings of MILCOM '94.

[3]  J. Treichler,et al.  A new approach to multipath correction of constant modulus signals , 1983 .

[4]  Ramdas Kumaresan,et al.  ESTIMATING THE PARAMETERS OF EXPONENTIALLY DAMPED OR UNDAMPED SINUSOIDAL SIGNALS IN NOISE , 1982 .

[5]  Jeffrey H. Reed,et al.  Interference rejection using the time-dependent constant modulus algorithm (CMA) and the hybrid CMA/spectral correlation discriminator , 1991, IEEE Trans. Signal Process..

[6]  Matthew L. Welborn.  Co-channel interference rejection using a model-based demodulator , 1995 .

[7]  Jeffrey H. Reed,et al.  Interference rejection using a hybrid of a constant modulus algorithm and the spectral correlation discriminator , 1989, IEEE Military Communications Conference, 'Bridging the Gap. Interoperability, Survivability, Security'.

[8]  S. Lawrence Marple.  A fast computational algorithm for and performance of the Kumaresan-Prony method of spectrum analysis , 1983, ICASSP.

[9]  Jeffrey H. Reed,et al.  Co-channel interference rejection using a model-based demodulator for AMPS and NAMPS , 1996, Proceedings of Vehicular Technology Conference - VTC.

[10]  Jeffrey H. Reed,et al.  Interference rejection using time-dependent constant modulus algorithms , 1989, Twenty-Third Asilomar Conference on Signals, Systems and Computers, 1989..

[11]  Steven Kay,et al.  Modern Spectral Estimation: Theory and Application , 1988 .