End-to-end QoS framework for heterogeneous wired-cum-wireless networks

With information access becoming more and more ubiquitous, there is a need for providingQoSsupport for communication that spans wired and wireless networks. For the wired side, RSVP/SBM has been widely accepted as a flow reservation scheme in IEEE 802 style LANs. Thus, it would be desirable to investigate the integration of RSVP and a flow reservation scheme in wireless LANs, as an end-to-end solution for QoS guarantee in wired-cum-wireless networks. For this purpose, we propose WRESV, a lightweight RSVPlike flow reservation and admission control scheme for IEEE 802.11 wireless LANs. Using WRESV, wired/wireless integration can be easily implemented by cross-layer interaction at the Access Point. Main components of the integration are RSVP-WRESV parameter mapping and the initiation of new reservation messages, depending on where senders/receivers are located. In addition, to support smooth roaming of mobile users among different basic service sets (BSS), we devise an efficient handoff scheme that considers both the flow rate demand and network resource availability for continuous QoS support. Furthermore, various optimizations for supporting multicast session and QoS re-negotiation are proposed for better performance improvement. Extensive simulation results showthat the proposed scheme is promising in enriching the QoS support of multimedia applications in heterogeneous wired-cum-wireless networks.

User mobility prediction in hybrid and ad hoc wireless networks

Next Generation Networks will employ hybrid network architectures using both cellular and ad hoc networking concepts. The vision of real-time
multimedia services requires that mobility management be addressed in a proactive manner. If the user movements can be predicted accurately in a
hybrid network environment then handoff/cluster change, resource reservation and context transfer procedures can be efficiently completed as required by node mobility. In this work we propose a sectorized ad hoc mobility prediction scheme for cluster change prediction. Simulation study of the scheme shows it to be efficient in terms of prediction accuracy and prediction related control overhead despite randomness in user movement.

Mobility prediction for seamless mobility in wireless networks

One of the requirements for seamless mobility is efficient resource reservation and context transfer procedures during handoff. If context transfer and resource reservation can occur prior to handoff continuation of the same level of service as at the previous connection point is possible. Resource reservation is required to be non-aggressive for optimal use of limited bandwidth and a low call-blocking probability. In this work we present a method of mobility prediction that can aid in achieving seamless mobility. In order to optimise the efficiency of a resource reservation algorithm we believe accurate prediction of the future movements of the user is required.

A review on current work in mobility prediction for wireless networks

The vision of next generation networks (4G & beyond) is to make possible seamless mobility across heterogeneous networks and to support real-time multimedia services. This would require intra/inter-domain handovers and service reconfiguration procedures to be completed with minimum latency. Mobility Prediction has been identified as a key abettor to this goal. The increasing ease of coupling between the mobile user and the network requires that a mobility prediction scheme that is to be deployed in next generation networks be capable of high levels of prediction accuracy despite randomness in user movement. In this work we have presented a survey on mobility prediction schemes that have been proposed for wireless networks. The results of our simulation study focused on the robustness of different schemes to randomness in user movement are also presented.

An adaptive policy-based vertical handoff algorithm for heterogeneous wireless networks

The next generation of wireless networks is envisioned as convergence of heterogeneous radio access networks. Since technologies are becoming more collaborative, a possible integration between IEEE 802.16 based network and previous generation of telecommunication systems (2G, ..., 3G) must be considered. A novel quality function based vertical handoff (VHO) algorithm, based on proposed velocity and average receive power estimation algorithms is discussed in this paper. The short-time Fourier analysis of received signal strength (RSS) is employed to obtain mobile speed and average received power estimates. Performance of quality function based VHO algorithm is evaluated by means of measure of quality of service (QoS). Simulation results show that proposed quality function, brings significant gains in QoS and more efficient use of resources can be achieved.

Piggyback hunting-browsing the internet in Australia via unsecured wireless networks : virtual theft or acceptable behaviour in an online world?

In a world that is increasingly dominated by the Internet, there is a growing demand for low cost access at the users convenience. The expansion of wireless Internet networks, in particular unsecured wireless Internet networks, gives rise to novel challenges for the regulation of Internet access. The ability to access unsecured wireless Internet networks with ease and with very little impact upon the owner of the network suggests that such 'piggybacking' may be criminal behaviour or may amount to an actionable civil wrong. This paper will explore the legal ramifications of piggybacking an unsecured wireless network with knowledge that there is no entitlement to the use of the network and will consider what Australian authorities should do about this situation. This paper will look at the position in Australia and juxtapose this with that of the United Kingdom and the United States of America. In both the United Kingdom and the United States of America prosecutions have taken place of individuals who knowingly accessed unsecured wireless
networks for their own personal use.

Resource-aware speculative prefetching in wireless networks

Mobile users connected to wireless networks expect performance comparable to those on wired networks for interactive multimedia applications. Satisfying Quality of Service (QoS) requirements for such applications in wireless networks is a challenging problem due to limitations of low bandwidth, high error rate and frequent disconnections of wireless channels. In addition, wireless networks suffer from varying bandwidth. In this paper we investigate object prefetching during times of connectedness and bandwidth availability to enhance user perceived connectedness. This paper presents an access model that is suitable for multimedia access in wireless networks. Access modelling for the purpose of predicting future accesses in the context of speculative prefetching has received much attention in the literature. The model recognizes that a web page, instead of just a single file, is typically a compound of several files. When it comes to making prefetch decisions, most previous studies in speculative prefetching resort to simple heuristics, such as prefetching an item with access probabilities larger than a manually tuned threshold. This paper takes a different approach. Specifically, it models the performance of the prefetcher, taking into account access predictions and resource parameters, and develops a prefetch policy based on a theoretical analysis of the model. Since the analysis considers cache as one of the resource parameters, the resulting policy integrates prefetch and cache replacement decisions. The paper investigates the effect of prefetching on network load. In order to make effective use of available resources and maximize access improvement, it is beneficial to prefetch all items with access probabilities exceeding certain threshold.

A cache-based mobility-aware scheme for real-time continuous media delivery in wireless networks

Providing real-time or continuous media (CM) application services in wireless networks poses a significant challenge, as it requires timely delivery of data in a best-effort network. In this paper, we propose a cache-based scheme for mobility-aware, CM applications. The proposed scheme exploits a previously proposed caching strategy to complement Mobile-IP by placing services closer to migrated mobile nodes. The central idea of this work is based on the migration of sessions in order to facilitate uninterrupted delivery of CM in mobile environments. The performance of the proposed scheme is investigated by simulation studies. In particular, the effect of the proposed scheme on several QoS parameters under varying conditions of mobility and CM data is measured.