Growth in mobile telecommunications was
met with great enthusiasm in Nigeria at its early stages but later
resulted in frustration due to diminished quality of service (QoS)(1).
In Nigeria and many other countries, mobile communication has been
troubled with complications spanning across human and technical issues.
However, because good quality of service must have been enjoyed before
the time of bad receptions, it becomes important to study the underlying
reasons for such drop in signal quality delivered(2). Obstacles and surfaces within the vicinity of the device have an effect on the path characteristics (3).
Signal propagation models then, are used largely in network planning,
most especially for conducting feasibility studies and during initial
deployment of mobile communications systems. They are also very useful
for performing analyses on interference as the deployment of these
These models may be broadly categorized
into three kinds namely; empirical, deterministic and stochastic.
Empirical models are those based on observations and measurements alone.
These models are mainly used to predict the path loss, but models that
predict rain-fade and multipath have also been proposed. The
deterministic models make use of the laws governing electromagnetic wave
propagation to determine the received signal power at a particular
location. Deterministic models often require a complete 3-D map of the
propagation environment (e.g. ray-tracing model). Stochastic models,
however, see the environment as a collection of random variables making
them the least accurate but requiring very minimal information about the
environment and make use much less processing power to generate their
The Walfisch-Ikegami model is an
empirical model from J. Walfisch and F. Ikegami and was further
developed by the COST 231 project. This is now called the COST-
Walfisch-Ikegami Model. The accuracy of this model is limited to its
consideration of buildings only in the vertical plane and quite high
because in urban environments, multiple diffractions over rooftops are
predominant. Wave guiding effects due to several reflections are not
considered however, in the model(5).
The study is borne out of the need to
understand why hitherto good quality of service enjoyed by end users of
GSM telecommunications suddenly deteriorates and in a way as to
understand how physical and environmental factors play a part in this
1.3 Problem Statement
The problem addressed here is to compare
the results of Walfisch-Ikegami model for pathloss with observed path
loss by determiningthe strength of GSM signals at different locations of
varied site parameters with respect to base stations’ within the
University of Ilorin Campus.
1.4Aim and Objectives
The aim of the studies is to determine the suitability of the Walfisch-Ikegami model in the determination of path-loss and signal strength of mobile communication lines within the University of Ilorin Campus.
The objectives in this project work are to:
i. Measure signal
strength and collect data and parameters for the verification of the
Walfisch-Ikegami pathloss model.
ii. Develop an algorithm for an application to calculate the Walfisch-Ikegami prediction model
iii. Compare predicted
with observed signal strength and consequent path-loss hence, identify
the criteria determining the suitability and usefulness of the
Walfisch-Ikegami path-loss model.
The work done here, is focused on
studying the behavior of propagated signals making use of the
Walfisch-Ikegami pathloss model to predict the signal strength of which
the Unilorin campus (located in Ilorin, Kwara state and covers about
75,000 hectares north and south) (6)serves as a
quasi-laboratory to confirm the theory.The area of interest are
characterized by sets of two-storey buildings that have evenly spaced
pattern within the University of Ilorin campus.
- Determine path-loss parameters;
- Take readings of signal strength obtained from mobiles device using a named method;
- Compare readings with the theoretical Walfisch-Ikegami path-loss model calculations; and hence make inferences from results
Chapter twopresents essential and
related background knowledge including the basics of path loss modelling
paying credence to how the GSM works vis-à-vis features and GSM network
parameter and workdone on the Walfisch-Ikegami Model. In Chapter three,
a more detailed work is presented on the actual methodology employed in
the course of the project work.
Chapter four analyses theoretical model
calculation with respect to observed values. Comments and judgment are
passed on the data obtained from the studies. Finally, chapter five
summarizes the project work, avails recommendations and conclusions of