Planung und Modellierung von WLAN-/ WiMAX-Netzwerken


WLAN hat in sämtliche Bereiche des öffentlichen Lebens Einzug gehalten. Der neue
Standard WiMAX wird in Zukunft bei der Entwicklung von regionalen Netzen eine große
Rolle spielen. Die Planung solcher Funknetze mit einer flächenhaften Abdeckung gestaltet
sich als schwierig. Ziel dieser Arbeit ist es, einen Überblick über neue WLAN- und WiMAX-
Standards zu geben. Es soll weiterhin der Stand von Forschung und Entwicklung von
Modellen und Algorithmen zur Planung von Funknetzen dargestellt und untersucht werden,
wie diese speziell für den WiMAX-Standard genutzt werden können. Außerdem sollen schon
bestehende Projektierungstools für WLAN-Funknetze untersucht werden. Darauf aufbauend
soll ein eigenes Tool konzipiert werden mit dem sich Funknetze, im speziellen WiMAX-
Netze, auf der Grundlage der zuvor untersuchten Modelle und Algorithmen planen lassen.

Research motivation and aim

This research thesis was made in the context of the “Computer Aided Network Design
Utility” (CANDY). The project runs at the institute of computer science at the Technical
University of Dresden. It is dedicated to the development of a tool that enables also non-
network-experts to configure a network by themselves. The programme will include different
tools. One part is dealing with the special requirements of radio networks. In order to
guarantee interoperability amongst the tools a new language has been worked out which is
called “Network Design Modelling Language” (NDML). NDML is based on XML grammar.
In order to meet the special requirements of radio networks RadioNDML was suggested.

The task of this thesis was to analyse the functionality of existing network design programmes
and to develop a concept for a radio network planning tool.


This thesis deals with the planning and modelling of wireless networks. The first section is
about the basics of network planning. It is supposed to give an impression of all necessary
steps of radio network planning and therefore of the software requirements.

In the second part an overview above the specifications of the IEEE 802.11 and IEEE 802.16
standards shall be presented.

The third and forth chapter will give an overview about current wave propagation and
visualisation models. The aim is to find a suitable model for all applications and wireless
standards in the radio network part of the CANDY project.

Furthermore already existing WLAN design tools are to be examined. Therefore a closer look
towards the options that are nowadays provided by those tools is taken. The section will finish
with a table naming the advantages and disadvantages of each programme.
In the sixth part of this thesis a concept for the radio network design tool that will be needed
in the CANDY project is suggested. Hence the knowledge about the previously examined
tools is combined with the facts about network design and special requirements of CANDY in
order to achieve a concept how the radio network tool might work.

The seventh section will suggest some extensions to RadioNDML.

The last part gives an outlook about future development.
1 Basic knowledge in radio network planning

Network planning consists of several tasks. At the beginning an initial proposition of the
hardware - like antennas and base stations - is to be found. The next steps are the optimisation
of cost, capacity, coverage, complexity and the signal-to-noise-ratio. Unfortunately one
cannot be done without neglecting another. If the capacity of the network is for example
supposed to be rather high the complexity and the costs of the system will increase. Therefore
it is important to define one’s priorities before starting to plan a network.

Also network planning cannot be done simply at a computer since all the calculations are just
estimations of the real world. Hence it is necessary to do a radio frequency survey after the
radio network simulation. This means that there has to be a temporary installation of the
selected hardware solution in the environment at the predetermined location.

1.1 Fresnel Zone

The Fresnel Zone covers the area around the line of sight (LOS) in which radio waves are
propagated after they left the transmitting antenna. It describes several elliptical areas. In
radio networks normally just the first elliptical area is considered to be the most important
one. There are also the 2nd, 3rd and .... Fresnel Zone. All odd numbers represent the
amplifying signal superposition and all even numbers the weakening signal superposition. It
can be calculated with the following formula:

32 . 17 ∗ =

r radius in metres
d distance in kilometres
f frequency in GigaHertz


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