Adaptation, optimisation and simulation of the CSMA/CA protocol for a low earth orbit satellite UHF link
Date
2006-12
Authors
Cawood, Andrew Dudley
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
A low earth orbit satellite is to provide the telecommunications link to facilitate email
services to rural areas, where the infrastructure necessary for e-mail is lacking
(e.g. no telephone lines). Communication time with this satellite from any particular
point on the ground is less than one hour per day. It is thus of utmost importance
to maximise the data throughput rate for the system.
The contribution of this thesis is to improve the performance of CSMA/CA by
adapting and optimising it for the above application. This improved protocol is
used to regulate data flow through the system. Specific attention is given to the
comparison of various random variable distributions for use as the back-off random
variable.
Two pieces of software are further contributed. First, a set of MATLAB scripts
which are used for comparing various back-off random variable distributions and
optimising each of these distributions. Secondly, an extensive (more than 2500 lines
of code) OMNeT++ simulation of the improved CSMA/CA protocol, complete with
MATLAB scripts for setting up multiple simulation runs and plotting the results.
Both pieces of software accept the system constraints as parameters, and are thus
easily adaptable for a similar system which may use the same protocol, but has
different parameters.
It is concluded that the set of MATLAB scripts are a fairly accurate tool for
optimising throughput, as is confirmed by the OMNeT++ simulations, and that
OMNeT++ has merit for simulating the given type of system and protocol.
Description
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.
Keywords
Carrier-sense multiple access, Artificial satellites in telecommunication, Dissertations -- Electronic engineering, Theses -- Electronic engineering