Performance Analysis of an Adaptive Hybrid Search Code Acquisition Algorithm for DS-CDMA Forward Links

Hyung-Rae PARK  

IEICE TRANSACTIONS on Communications   Vol.E88-B   No.4   pp.1586-1593
Publication Date: 2005/04/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.4.1586
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
DS-CDMA,  code acquisition,  hybrid search,  mean acquisition time,  CFAR,  

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We analyze the performance of an adaptive hybrid search code acquisition algorithm for direct-sequence code division multiple access (DS-CDMA) systems under slowly-moving mobile environments. The code acquisition algorithm is designed to provide the desired feature of constant false alarm rate (CFAR) to cope with nonstationarity of interference in CDMA forward links. An analytical expression for the mean acquisition time is first derived and the probabilities of detection, miss, and false alarm are then obtained for frequency-selective Rayleigh fading environments. The fading envelope of a received signal is assumed to be constant over the duration of post-detection integration (PDI), which is most reasonable, especially for slowly-moving mobile environments. The performance of the designed code acquisition algorithm shall be evaluated numerically to examine the effect of some design parameters, such as the sub-window size, the size of the PDI, the decision thresholds in search and verification modes, and so on, considering IMT-2000 environments.