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Byline: Farshad Eshghi (1), Ahmed K. Elhakeem (1) Keywords: IEEE 802.11; wireless LAN; frequency hopping; direct sequence; interference model; bit error rate analysis Abstract: In this paper the bit error probability of the SFH/MFSK system in presence ofwideband and tone interference in a fading environment is evaluated.Simultaneous license-free operation of tone-like applications, FrequencyHopping (FH), and Direct Sequence (DS) based LAN clusters is assumed to be theprime interference facing the subject FH wireless LAN (of the IEEE 802.11standard). The wideband DS interference is considered to have asinc.sup.2() shape Power Spectral Density (PSD) centered at the middleof FH signal band and tone interferers are assumed to be spread over the wholeFH band of the intended signal. Assumptions of slow non-selective fading alongwith slow hopping justify a quasi-static treatment. Results shows that the FHsystem is more sensitive to tone interference and fading and less sensitiveto wideband interference variations. The paper sheds light on the performanceof wireless LAN operation in the unlicensed free band where many other LANsmay exist. Author Affiliation: (1) Department of Electrical and Computer Engineering, Concordia University, Montreal, QC, H3G 1M8, Canada Article History: Registration Date: 13/10/2004

Byline: Qiang Shen (1), Bo-Xiu Wua (2), Ahmed K. Elhakeem (3) Keywords: spread spectrum; CDMA; Rake receiver; fading channel; linear predictor; adaptive algorithm; impulsive interference Abstract: Parameter estimation of the multipath and fading channel is investigated for the Rake combiner used in a CDMA system with coherent demodulation. A linear predictor is proposed to obtain a better estimation. Since the industrial interference environment is generally impulsive, a parallel LMS adaptive algorithm is proposed to reduce the impact of impulsive noise on predictor weights adjustment. Performance analysis and computer simulations are presented. Author Affiliation: (1) Nortel, P.O. Box 3511, Station C, Ottawa, Canada, K1Y 4H7, E-mail (2) Radio Engineering Department, Southeast University, Nanjing, 210018, P.R.China (3) Electrical and Computer Engineering Department, Concordia University, Montreal, Canada, H3G 1M8 Article History: Registration Date: 28/09/2004