Abstract
Providing Internet connectivity on public transport has the potential to open up a new dimension of consumer entertainment and productivity. However, the potentially large population density and high handover rates of mobile users aboard a public transport vehicle necessitate robust and scalable quality-of-service (QoS) provisioning mechanisms designed for such environments that can improve both pre-session and in-session signalling efficiency.A number of Quality of Service (QoS) aggregation policies are proposed that reduce the frequency with which QoS requests are made to a network, and hence increase overall pre-session signalling efficiency. However, since these policies are based on a static, request-rate-dependent parameter, operational inefficiency can occur under highly variant rates of request. Therefore, a cost-driven policy is proposed that is shown to increase signalling efficiency compared with other policies, while, at the same time, not putting users at a disadvantage with long and unpredictable waiting times to establish a session. When the access network becomes congested, signalling efficiency is drastically reduced under the cost-driven policy. Therefore, two separate \overlay" policies are proposed to work in place of the cost-driven aggregation policy during periods of congestion: a dynamic policy and a static policy. The static policy is shown to significantly out-perform the case in which no overlay policy is used, significantly increasing cost-efficiency whilst reducing user waiting times. Finally, attention is given to the issue of in-session QoS provisioning. Micro-mobility protocols play an important role in providing seamless handover support to terminals. However, such protocols typically suffer from bottleneck congestion, which can lead to a degradation of signalling efficiency and reduced QoS when they are used by moving networks. Therefore, a novel mechanism is proposed that alleviates these problems, and an implementation of the protocol within the Next Steps in Signaling framework is detailed.
| Date of Award | 2010 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Abdol-Hamid Aghvami (Supervisor) & Andrej Mihailovic (Supervisor) |