Research Articles (Computer Science)

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https://hdl.handle.net/10566/52
The research papers in this collection represent the work of several projects.

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Browsing by Subject "Ad hoc network"

Now showing 1 - 4 of 4
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    An analysis of voice over Internet Protocol in wireless mesh networks
    (IEEE, 2014) Meeran, Mohammed Tariq; Tucker, William David
    The paper focuses on analyzing the affects of wireless mesh networks with some mobile nodes on Voice over Internet Protocol service quality. Our interest is to examine this in simulation to learn how to better deploy voice services on such a network in a rural community. Wireless mesh networks' unique characteristics like multi-hop, node mobility, coverage, and medium usage cause quality of service issues for Voice over Internet Protocol implementations. This research considers three wireless mesh scenarios on 26 mesh nodes. In the first scenario all nodes are stationary. In the second, 10 nodes are mobile and 16 nodes are stationary. In a third scenario, all nodes are mobile. Nodes move at a walking speed of 1.3m per second. The analysis and results show that while node mobility can increase packet loss, delay, jitter, Voice over Internet Protocol implementations in wireless mesh networks can be successful if there is no background traffic. We recommend that Voice over Internet Protocol implementations in wireless mesh networks with some mobile nodes and background traffic be supported by quality of service standards; else it can lead to service level delivery failures.
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    Optimisation of SlotTime for a single-radio Mid-Range Multi-hop Wireless Mesh Network
    (Telkom SA, 2014) Rey-Moreno, Carlos; Tucker, William David; Simo-Reigadas, Javier
    This paper presents the business context and results of an optimisation exercise for a single-radio mid-range multi-hop wireless mesh network for the provision of VoIP services. This WiFi mesh network physically covers 30 square kilometres in rural South Africa with a dozen solar-powered nodes. The firmware multiplexes the single radios in adhoc and infrastructure modes, essentially providing a distributed hotspot that can be used for WiFi-based Asterisk attachment in addition to POTS handsets via an ATA adapter in a node. We argue that this architecture is comparable yet cheaper and easier to install and maintain than multi-radio systems with directive antennas. Measurement of a range of values revealed a SlotTime setting that maximises throughput by 115%. We leverage this finding to argue a business case for a ground up community-based mesh network like this one; to provide a win-win situation for local residents and operators with free internal calls backed up by revenues from low cost voice breakout, Internet services and solar-based mobile phone charging. Our novel approach offers an accessible and affordable business model based on increased traffic volume from residents in a rural area that have mobile connectivity yet cannot afford to use it. The optimised architecture described herein offers an attractive and complementary alternative.
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    Reliable communication across ad hoc networks
    (Telkom, 2008) Daniels, Francois; Tucker, William David
    This paper presents a fully decentralised peer-topeer voice communication tool intended for use across mobile ad hoc networks (MANET) by distributed groups who desired collaboration. We examined the synergy between MANETs and peer-to-peer virtual overlay networks which allowed the creation of ad hoc applications. One style of communication considered suitable for task oriented distributed group collaboration was push-to-talk. This research was focused on providing a push-to-talk communication platform suitable for deployment across MANETs. The research methodology employed was a proof of concept approach within a classical experimental computer science paradigm. We developed a prototype which used JXTA, a peer-to-peer virtual overlay network, to provide push-to-talk functionality across MANETs. Guaranteed delivery of messages was provided via a peer-to-peer voicemail delivery system. While the system did what intended we show that JXTA had a problem with the efficient delivery of voice samples.
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    Socio-economic aspects of voice-over-IP technology in rural SA
    (Telkom, 2012) Roro, Zukile; Rey-Moreno, Carlos; Tucker, William David; Siya, Masbulele Jay
    This paper describes work in progress towards developing a business case and preliminary design for an 802.11-based mesh network in the remote rural community of Mankosi in the Eastern Cape province of South Africa. Aside from the technical challenges to building the network to be sustainable in the long term, this network needs to generate some revenue. Hence, there needs to be a business model that has revenue generation potential. This study will explore the economical and social aspects of voice over Internet- Protocol as a service for this community. After talking to the village leaders, we learned that there is a demand for telecommunication services and that most of them were interested only in telephony service. Very few villagers were interested in or had any knowledge about the Internet. We also learned that most of their cellular phone calls are local within the Mankosi community. This allows us to deploy an experimental local telephony service; a perfect opportunity for a low-cost and lowcosting inverse mesh infrastructure that can easily be connected to breakout and Internet services in the future.