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A Novel EKF-Based Recovery in DS Scheme for DS/CDMA Systems Tracking Code Delay

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Abstract

Classical delay-lock loops (DLL) have beenwidely considered for code synchronization purposes inDS/CDMA systems, although they have not been devised foroperation when channel fading is present. This paper describes a new code synchronizationscheme based on a previously proposed extended Kalmanfilter (EKF) approach. The scheme proposed in this paperis able to operate under low signal-to-interference ratios (SIR), usual at the receiver input incellular CDMA mobile environments, and it outperformsthe behavior of previously proposed EKF-based schemes,which failed in such environments. Performance results under realistic mobile environment conditionsare shown in terms of the mean time to lose lock (MTLL)and the tracking error varianceστ 2 for a wide range ofSIR values and under Rayleigh fading. Moreover, the Cramer-Rao lower boundonστ 2 is also computed inorder to validate the results obtained viasimulations.

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Diaz, P., Agusti, R. A Novel EKF-Based Recovery in DS Scheme for DS/CDMA Systems Tracking Code Delay. International Journal of Wireless Information Networks 4, 89–100 (1997). https://doi.org/10.1023/A:1018837823343

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  • DOI: https://doi.org/10.1023/A:1018837823343

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