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Corresponding Author

Ghuneim, Atef

Subject Area

Electrical Engineering

Article Type

Original Study

Abstract

In DS-CDMA receivers, the synchronization error between the received signal and the generated code is about one chip duration in Interim Specification 95 (IS-95) system. This error makes the correlator to produce the peak of the 1st arrival multipath signal away from its position up to about 800 ns. This small error in time leads to severe mistakes especially in positioning applications. So, the delayed versions of the code sequence with delay less than one chip duration need to be defined. In this paper, the multipaths with delays less than one chip duration are modeled as tapped- delay line model. A Kalman filter algorithm is applied to estimate the tap coefficients under the situation of known channel statistics. The tap coefficient higher than 0.5means that its corresponding path is an effective path. In case of more than one effective path, the algorithm gives a weight higher than 0.5 only for the path with the smallest delay. This is sufficient, since the reception timing reference is at the 154 arrival signal peak. The simulations (real different cases applied to 3 - pach and 5 path models at low and high SNRs. The results show that the algorithm works well in the different considered situations.

Keywords

Kalman filter; DS-CDMA. multipath fading; tapped-delay- line model

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