Browsing by Author "Kobo, Hlabishi Isaac"

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    Internet protocol-based push to talk
    (Telkom, 2010) Kobo, Hlabishi Isaac; Tucker, William David; Norman, Michael
    This paper discusses a way of offering voice instant messaging based on Internet Protocol using Session Initiation Protocol. The purpose of this investigation is to enhance the modern social communication amongst the people of South Africa who are already accustomed to text-based instant messaging. The proposed application aims to implement the traditional Push-to-Talk technology using Internet Protocol. Thus the proposed IP-based Push-to-Talk is a new approach to voice communication which emulates a walkie-talkie system. On the mobile phone IP-Push-to-Talk herein referred to as Push-to-Talk over a cell phone can be viewed as a voice SMS. The adoption of a Push-to-Talk service was inspired by the fact that it applies half-duplex communication. This enhances the primary objective of offering a cheap voice instant messaging. In half-duplex communication, only one person can talk at a time, thereby avoiding bidirectional charging. The project was implemented on two platforms, a PC and a mobile phone. The PC Push-to-Talk was implemented through client server approach whilst the mobile Push-to-Talk through a peer-to-peer approach. Several software engineering strategies were used for user requirements gathering as well for testing. Six users participated in the test and the results were gathered through questionnaires. The results showed that, half-duplex communication is efficient and yet very economical as it makes less usage of system resources.
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    Situation-aware routing based on link quality for static mesh networks with mobile nodes
    (Telkom, 2011) Kobo, Hlabishi Isaac; Tucker, William David; Liu, Xiao Ming
    Situation-aware routing seeks to improve quality of service on hybrid wireless mesh networks by making routing decisions based on the current situation of the network. BATMAN-adv is a mesh routing protocol that counts beacons as a link quality metric. We modified BATMAN-adv to give more recently received beacons more weight, thereby giving a more precise indication of the current state of a link. We then compared the original protocol with our modification in a small laboratory test bed. Results show little relation between jitter and packet loss. Jitter is, however, proportional to throughput. The average throughput achieved on both protocols was almost the same but we noticed that the throughput on our modified version increases as the network grows. Our protocol modification suffered from packet loss at low bandwidth rates but this reduces as the transfer rate increases and buffer size shrinks. We conclude that our situationaware protocol modification shows potential to address issues pertaining to scalable and congested static mesh networks with mobile nodes.
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    Situation-aware routing for wireless mesh networks with mobile nodes
    (IIMC International Information Management Corporation, 2012) Kobo, Hlabishi Isaac; Tucker, William David
    This paper describes a situation-aware algorithm based on the current situation of a mesh network with mobile nodes that improves quality of service. After running laboratory performance tests, we concluded that a situation-aware mesh routing protocol offers potential to address issues pertaining to mobility, congestion and scalability in dynamic mesh networks with mobile nodes. Such networks appear promising to provide connectivity to people living in rural areas in developing regions of Africa, and can be easily interconnected to telco-styled networks through gateways for voice and Internet services. Such services can remain free in the mesh, yet can also be billed for interconnection. Our vision offers an attractive business model for up scaling a rural customer base for telcos, while at the same time offering increased quality of service for mobile users on rural mesh networks.