Browsing by Author "Hsu, Nicolas Y. -H."

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Performance Analysis of a Complex Multicode Tracking Loop in Bandlimited Rayleigh Fading Channels
(2011-08-01)
Hsu, Nicolas Y. -H.
;
Su, Yu T.
;
Lin, Yuan-Bin
;
電子工程學系及電子研究所
;
電信工程研究所
This paper presents the root-mean-squared tracking error performance analysis of a class of coherent digital delay-locked loops for multicode direct sequence spread spectrum signals in bandlimited correlated Rayleigh fading channels. In the transmit side, multiple independent PSK-modulated data streams in the in-phase and qudrature phase branches are spread by short mutually orthogonal codes before being further complex spread by a long complex PN code. We assume that the system employs a pilot code channel to assist the receiver's synchronization and channel estimation. The proposed code tracking loop incorporates the pilot-aided channel estimator and derives the timing error from all short-code-spread subchannels. Our analysis takes into account the effects of imperfect channel estimate, correlated frequency selective Rayleigh fading and band-limiting. Numerical results are presented to quantify the impact of the resulting multipath interference within the same code channel and amongst different code channels.