Acquisition Performance with Adaptive Threshold for a FH/SSMA System

Jin Young KIM  Jae Hong LEE  

IEICE TRANSACTIONS on Communications   Vol.E79-B   No.3   pp.297-307
Publication Date: 1996/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Advanced Adaptive Radio Communication Technologies)
Category: Access, Network
acquisition,  adaptive threshold,  FH/SSMA,  

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A new matched-filter (MF) acquisition scheme with adaptive threshold is proposed for a frequency-hopped/spread-spectrum multiple-access (FH/SSMA) system. Detection and false alarm probabilities are derived for combined interference environments. The combined interference consists of partialband noise jamming or tone jamming, multiple access interference (MAI), multipath interference, and thermal noise. We use Gaussian approximation for modeling the MAI and multipath interference. Equal power assumption of the users is employed which is typically used in the SSMA system analysis. In the proposed scheme, MF output is compared to an adaptive threshold determined by the number of jammed frequency slots. It is shown that the proposed adaptive-threshold acquisition scheme achieves higher detection probability and lower false alarm probability than a conventional fixed-threshold scheme for each jammed fractional bandwidth, JSR, the number of multipaths, and the number of users. It is also shown that adaptive threshold achieves faster acquisition and higher packet throughput than fixed threshold in application to FH/SSMA packet radio system.