Analysis of an LMS linear equalizer for fading channels in decision directed mode

Kavitha, V and Sharma, V (2020) Analysis of an LMS linear equalizer for fading channels in decision directed mode. In: 13th European Wireless Conference: Enabling Technologies for Wireless Multimedia Communications, 1-4 April 2007, Paris.

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Abstract

We consider a time varying wireless fading channel, equalized by an LMS linear equalizer in decision directed mode (DD-LMS-LE). We study how well this equalizer tracks the optimal Wiener equalizer. Intially we study a fixed channel. For a fixed channel, we obtain the existence of DD attractors near the Wiener filter at high SNRs using an ODE, approximating the DD-LMS-LE. We also show, via examples, that the DD attractors may not be close to the Wiener filters at low SNRs. Next we study a time varying fading channel modelled by an Auto-regressive (AR) process of order 2. The DD-LMS equalizer and the AR process are jointly approximated by the solution of a system of ODEs (ordinary differential equations). Using these ODEs, via some examples, the LMS equalizer is shown to track the instantaneous Wiener filter when the SNR is high, while it may not track the same at low SNRs. © EW 2007 - 13th European Wireless Conference: Enabling Technologies for Wireless Multimedia Communications. All rights reserved.

Item Type:	Conference Paper
Publication:	EW 2007 - 13th European Wireless Conference: Enabling Technologies for Wireless Multimedia Communications
Publisher:	Ecole Nationale Superieure de Techniques Avancees, ENSTA
Additional Information:	The copyright for this article belongs to Ecole Nationale Superieure de Techniques Avancees, ENSTA
Keywords:	Dynamical systems; Fading channels; Multimedia systems; Ordinary differential equations; Signal to noise ratio; Time varying networks, Autoregressive process; Decision-directed modes; Linear equalizer; LMS equalizers; System of odes; Time varying fading channels; WIENER filters; Wireless fading channels, Equalizers
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	23 Aug 2021 09:12
Last Modified:	23 Aug 2021 09:12
URI:	http://eprints.iisc.ac.in/id/eprint/65817

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