Páginas: 44 (10974 palavras) Publicado: 30 de março de 2012
Hindawi Publishing Corporation
EURASIP Journal on Wireless Communications and Networking
Volume 2010, Article ID 414927, 14 pages

Research Article
On the Evaluation of MB-OFDM UWB Interference Effects on
a WiMAX Receiver
Eduardo Cano, Alberto Rabbachin, Detlef Fuehrer, and Joaquim Fortuny
Institute for the Protection and Security of the Citizen, Joint ResearchCentre, European Commission, Ispra, 21027 Varese, Italy
Correspondence should be addressed to Eduardo Cano, eduardo.cano@jrc.ec.europa.eu
Received 1 November 2009; Revised 20 April 2010; Accepted 6 July 2010
Academic Editor: Yan Xin
Copyright © 2010 Eduardo Cano et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use,distribution, and reproduction in any medium, provided the original work is properly cited.
The European Commission has recently adopted specific power spectral density masks for ultra wideband (UWB) devices, with
detect and avoid capabilities, for coexistence with licensed standards. Under these regulations, a novel approach for analyzing the
UWB interference effects on the WiMAX downlink isprovided in this paper by means of a novel theoretical computation of the bit
error rate (BER), simulation results, and measurements in a conducted modality. New analytical BER expressions for both uncoded
and coded WiMAX systems, impaired by a single multiband-OFDM (MB-OFDM) UWB interference signal, are obtained in this
paper for a Rayleigh fading channel. The BER is expressed in terms of thecharacteristic function of the interference signal. The
maximum permissible interference levels and the signal-to-interference (SIR) values, which allow the UWB interference effects to
be considered negligible, are estimated in this paper from simulation and measurement results. The analysis considers a WiMAX
receiver operating at its minimum sensitivity level. The BER, the symbol error probability(SEP), and the error vector magnitude
(EVM) of the WiMAX link are the metrics employed to characterize the interference effects for both frequency hopping and
nonfrequency hopping UWB interferers.

1. Introduction
The demand for reliable, fast, and low-cost data communications services for all types of wireless applications
and environments has increased rapidly in the last few
years. Often,different types of wireless networks coexist in
the same area and share the communications channel. In
such situations, if appropriate mitigation techniques are not
applied, wireless signals coming from different sources could
interfere with each other causing a considerable degradation
in system performance. The coexistence scenario analyzed in
this work corresponds to the case of a single ultrawideband
(UWB) transmitter operating at the same frequency band
as a WiMAX receiver. UWB technology is established as a
viable candidate for future wireless personal area networks
(WPANs) that require the processing of information with
low-power sources at very high speeds across short distances
(order of 10 m) [1]. Alternatively, WiMAX systems, which
are derived from the IEEE 802.16 airinterface standards [2,
3], allow for high-speed broadband connectivity in cellular
point-to-multipoint wireless metropolitan area networks
(WMAN) of wider range (order of 5 Km).

The Federal Communications Commission (FCC) in the
US approved the use of UWB technology for commercial
applications under part 15 of its regulations in February 2002
[4]. The FCC report and order defined UWB as asignal with
bandwidth to central frequency ratio greater than 20% or,
alternatively, with a −10 dB bandwidth exceeding 500 MHz
in the frequency range of 3.1–10.6 GHz. The FCC permits
UWB devices to operate on an unlicensed basis following
restrictive power spectral masks for both indoor and outdoor
environments. A maximum mean effective isotropic radiated power (EIRP) spectral density of...
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