Page 227 - ITU Kaleidoscope 2016

SYSTEMATIC ANALYSIS OF GEO-LOCATION AND SPECTRUM SENSING
AS ACCESS METHODS TO TV WHITE SPACE

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H. Mauwa , A. Bagula , M. Zennaro , E. Pietrosemoli , A. Lysko , T.X. Brown 4
1
ISAT Laboratory, Computer Science Department, University of The Western Cape (UWC),
Private Bag X17, Bellville, 7535, South Africa.
Email: {mhope, bbagula}@uwc.ac.za
2 T/ICT4D Laboratory, The Abdus Salam International Centre for Theoretical Physics,
Via Beirut 7, 34151 Trieste, Italy.
Email: {mzennaro, ermanno}@ictp.it.
3 Meraka Institute, Council for Scientific and Industrial Research,
Pretoria, South Africa
Email: alysko@csir.co.za.
4 Carnegie Mellon University, Department of ICT,
Kigali, Rwanda
Email: timxb@andrew.cmu.edu

ABSTRACT 1. INTRODUCTION

In the current static spectrum-allocation policies followed
by governmental agencies, licensed holders are assigned
Access to the television white space by white space devices
wireless spectra on a long-term basis. The static spectrum-
comes with a major technical challenge: white space devices
allocation policies have shown to be inefficient [1]. The inef-
can potentially interfere with existing television signals. Two
ficiency is more apparent in the TV broadcasting frequency
methods have been suggested in the literature to help white
band as several studies have shown that a huge portion of
space devices identify unused channels in the TV frequency
the assigned spectra is unused [1][2][3][4] most of the time.
band so that they can avoid causing harmful interference to
The unused TV channels (so called TV white spaces) have
primary services legally protected to run on the band. These
been hyped as the solution to meet the growing demand for
methods are geo-location spectrum database and spectrum
the wireless data transmission. At the moment, governments
sensing. Discussions in the literature have placed much em-
are seeking better and innovative techniques that will offer
phasis on the limitations of the spectrum sensing approach
new ways of exploiting the existing spectrum [5]. An effi-
and mainly based on the developed world environment ig-
cient long-term solution that has been proposed is dynamic
noring the performance requirements of the geo-location
spectrum access (DSA) [6].
database approach and how the absence of these require-
ments in a developing region could affect its performance. Detection of vacant channels by secondary devices called
This paper considers a broader analysis of the approaches white space devices (WSDs) is difficult as the vacant chan-
by looking at factors that can affect the performance of each nels vary according to location and time. Any secondary
approach and how the presence or absence of these factors access can potentially cause harmful interference to the pri-
in a developed region or developing region can affect their mary TV broadcasting services already running in the band
performance. In so doing, the paper highlights the need if the channel is mistakenly assessed as vacant. This places
to conduct more research on the performance of spectrum a mandatory requirement on any white space device (WSD)
sensing in developing regions where there are plenty of white to check if a primary user signal is present or absent in a
spaces to ascertain its use in these regions. channel before it goes ahead using it. Two techniques have
been suggested to help WSDs do this: geo-location spectrum
Keywords— Geo-location database, spectrum sensing, per- database and spectrum sensing.
formance factors, best approach Discussions in the literature have placed much emphasis on
the limitations of the spectrum-sensing approach, which are
based mainly on the developed world environment. This may
have been the case because the idea to use TV white space
Paper accepted for presentation at “ICTs for a Sustainable World”
ITU Kaleidoscope Conference, Bangkok, Thailand, 14-16 November 2016, (TVWS) originated from the developed world and the initial
http://itu.int/go/K-2016. experiments were conducted there. Critical performance re-

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