SATNAC 2008 Conference Papers
Network Planning & General Topics
Title: An Improved Capacity
Modeling Approach for 802.11 Protocols
Authors: Neville
Greyling (
Abstract: Despite the widespread deployment of IEEE 802.11 Wireless Local Area Network (WLAN) protocol, not much analysis has been done on modelling its performance, to determine what amount of users such a network can accommodate. In this paper one approach to such a model is introduced, in order to assist with capacity determination on WLAN networks. We introduce a model to compute the number of users that such a WLAN can accommodate. The model is applicable to applies to unsaturated traffic conditions, and is suited for all traffic arrival patterns. Further more, the model tries to emulate model such a network as accurately as possible with moderate simplifications.
Title: The Recursive Evaluation
of the M/M/r/K/K Queue
Authors: Ian Kennedy (University of the
Witwatersrand), Anthony Krzesinski (
Abstract: We
present a recursive form of the equation for the probability that the queueing
delay in an M/M/r/K/K queue is larger than a given bound. The recursive form is
computationally efficient and is not subject to numerical overflow. The
practical implication of the recursion is that the teletraffic engineer has an
accurate, practical formula for calculating the delay probability distribution
for switches where the calls are offered from a finite population.
Title: Characteristics of
Seasonal Attenuation and Fading for Line-of-Sight Links in South Africa
Authors: Modupe
Odedina (
Abstract: The
characteristics of seasonal rain attenuation are studied for five different
geographical locations in
Authors: Peter
Odedina (
Abstract: In
order to propose a reasonable prediction models for radioclimatic study, a reliable
radio propagation data is required. This radio propagation data can be either
primary radio propagation data or secondary. The secondary data can be
estimated from a relevant primary data. Primary radioclimatic data include
temperature, pressure and humidity or water vapour pressure, while secondary
radioclimatic data includes, refractivity data such as refractivity gradients,
ducting data, geoclimatic factor and also data that incorporate the effect of
earth curvature on radiowave propagation such as effective earth radius factor
(k-factor). In this presentation, our focus is on such secondary data. We have
used 10 years data (1985-1994) in three different regions of
Title: Route Selection
Impacts on Achieving Enhanced IMS QoS
Authors: Vitalis
Ozianyi (
Abstract: The
different planes in the IMS interact via specific reference points to deliver
multimedia services to the user. QoS provisioning for IMS communications has
been standardized for access networks only, with the assumption of an over
provisioned IP core. Effective provisioning of multimedia services requires
performance guarantee along the complete path of the sessions. End-to-end QoS
in IP networks is affected by the route traversed by the user traffic. Moreover
QoS guarantees in one ISP domain are not effective for transit traffic exiting
the domain. QoS extensions to exterior gateway routing protocols have been
proposed to transfer route QoS information beyond one autonomous system
(domain). This paper explores options for mapping inter-domain QoS information
learnt on the media plane into control plane session information for IMS QoS
control. Through testbed evaluations we show the effect of routing on delays
experienced in IMS communications.
Title: Solving the Extended Tree Knapsack Problem
(ETKP) with Fixed Cost Flow Expansion Functions
Authors: David
van der Merwe
(
Abstract: Parts
of the LATN (Local Access Telecommunication Network) planning problem can be
modelled with the Extended Tree Knapsack problem. The LATN can constitute up to 60% of total
network costs. In this paper a
partitioning algorithms using standard of the shelf software coupled with
enhanced modelling is presented.
Enhancements to the algorithms is presented along with empirical
results.
Authors: Suné von Solms (
Abstract: In this
paper, we introduce an algorithm for error detection and correction in random
network coding. The introduced technique exploits the encoding characteristics
of random network coding and uses the well known Hamming Code as a decoding
algorithm. For a network where random network coding is applied, this technique
can be a useful error detecting and correcting method that will improve the
network’s robustness.
Title: Mapping the Location
of 2.4 GHz Transmitters to Achieve Optimal Usage of an IEEE 802.11 Network
Authors: Daniel
Wells (
Abstract: This
paper describes the use of a low cost 2.4 GHz spectrum analyser, the MetaGeek
WiSpy device, in conjunction with custom developed client-server software for
the accurate identification of 2.4 GHz transmitters within a given area. The
WiSpy dongle together with the custom developed software allow for
determination of the positions of Wi-Fi transmitters to within a few meters,
which can be helpful in reducing the work load for physical searches in the
process of surveying the Wi-Fi network and geographical area. This paper
describes the tool and methodology for a site survey as a component that can be
used in organisations wishing to audit their environments for Wi-Fi
networks. The tool produced from this
project, the WiSpy Signal Source Mapping Tool, is a three part application
based on a client-server architecture. One part interfaces with a low cost 2.4
GHz spectrum analyser, another stores the data collected from all the spectrum
analysers and the third part interprets the data to provide a graphical
overview of the Wi-Fi network being analysed. The location of the spectrum
analysers are entered as GPS points, and the tool can interface with a GPS
device to automatically update its geographical location. The graphical
representation of the 2.4 GHz spectrum populated with Wi-Fi devices (Wi-Fi
network) provided a fairly accurate method in locating and tracking 2.4 GHz
devices. Accuracy of the WiSpy Signal Source Mapping Tool is hindered by
obstructions, interferences within the area or non line of sight.