Modelling the GSM handover protocol in CommUnity

CommUnity is a formal approach to software architecture. It has a precise, yet intuitive mathematical semantics based on category theory. It supports, at the methodological level, a clear separation between computation, coordination, and distribution (including mobility). It provides a simple state-based language for describing component behaviour that is inspired by Unity and Interacting Processes. It also addresses composition as a first class concern and accounts for the emergence of global system properties from interconnections. This paper describes the approach and available tool support by modelling essential aspects of the GSM handover protocol. We also sketch a framework that we are implementing for the distributed execution of such specifications using Klava, a Java library for mobile agent systems based on tuple spaces

MIPv6 Experimental Evaluation using Overlay Networks

The commercial deployment of Mobile IPv6 has been hastened by the concepts of Integrated Wireless Networks and Overlay Networks, which are present in the notion of the forthcoming generation of wireless communications. Individual wireless access networks show limitations that can be overcome through the integration of different technologies into a single unified platform (i.e., 4G systems). This paper summarises practical experiments performed to evaluate the impact of inter-networking (i.e. vertical handovers) on the Network and Transport layers. Based on our observations, we propose and evaluate a number of inter-technology handover optimisation techniques, e.g., Router Advertisements frequency values, Binding Update simulcasting, Router Advertisement caching, and Soft Handovers. The paper concludes with the description of a policy-based mobility support middleware (PROTON) that hides 4G networking complexities from mobile users, provides informed handover-related decisions, and enables the application of different vertical handover methods and optimisations according to context.Publicad

Delay-centric handover in SCTP

The introduction of the Stream Control Transmission Protocol (SCTP) has opened the possibility of a mobile aware transport protocol. The multihoming feature of SCTP negates the need for a solution such as Mobile IP and, as SCTP is a transport layer protocol, it adds no complexity to the network. Utilizing the handover procedure of SCTP, the large bandwidth of WLAN can be exploited whilst in the coverage of a hotspot, and still retain the 3G connection for when the user roams out of the hotspot’s range. All this functionality is provided at the transport layer and is transparent to the end user, something that is still important in non-mobile-aware legacy applications. However, there is one drawback to this scenario - the current handover scheme implemented in SCTP is failure-centric in nature. Handover is only performed in the presence of primary destination address failure. This dissertation proposes a new scheme for performing handover using SCTP. The handover scheme being proposed employs an aggressive polling of all destination addresses within an individual SCTP association in order to determine the round trip delay to each of these addresses. It then performs handover based on these measured path delays. This delay-centric approach does not incur the penalty associated with the current failover-based scheme, namely a number of timeouts before handover is performed. In some cases the proposed scheme can actually preempt the path failure, and perform handover before it occurs. The proposed scheme has been evaluated through simulation, emulation, and within the context of a wireless environment

Investigation of an intelligent personalised service recommendation system in an IMS based cellular mobile network

Success or failure of future information and communication services in general and mobile communications in particular is greatly dependent on the level of personalisations they can offer. While the provision of anytime, anywhere, anyhow services has been the focus of wireless telecommunications in recent years, personalisation however has gained more and more attention as the unique selling point of mobile devices. Smart phones should be intelligent enough to match user’s unique needs and preferences to provide a truly personalised service tailored for the individual user. In the first part of this thesis, the importance and role of personalisation in future mobile networks is studied. This is followed, by an agent based futuristic user scenario that addresses the provision of rich data services independent of location. Scenario analysis identifies the requirements and challenges to be solved for the realisation of a personalised service. An architecture based on IP Multimedia Subsystem is proposed for mobility and to provide service continuity whilst roaming between two different access standards. Another aspect of personalisation, which is user preference modelling, is investigated in the context of service selection in a multi 3rd party service provider environment. A model is proposed for the automatic acquisition of user preferences to assist in service selection decision-making. User preferences are modelled based on a two-level Bayesian Metanetwork. Personal agents incorporating the proposed model provide answers to preference related queries such as cost, QoS and service provider reputation. This allows users to have their preferences considered automatically

Quality aspects of Internet telephony

Internet telephony has had a tremendous impact on how people communicate. Many now maintain contact using some form of Internet telephony. Therefore the motivation for this work has been to address the quality aspects of real-world Internet telephony for both fixed and wireless telecommunication. The focus has been on the quality aspects of voice communication, since poor quality leads often to user dissatisfaction. The scope of the work has been broad in order to address the main factors within IP-based voice communication. The first four chapters of this dissertation constitute the background material. The first chapter outlines where Internet telephony is deployed today. It also motivates the topics and techniques used in this research. The second chapter provides the background on Internet telephony including signalling, speech coding and voice Internetworking. The third chapter focuses solely on quality measures for packetised voice systems and finally the fourth chapter is devoted to the history of voice research. The appendix of this dissertation constitutes the research contributions. It includes an examination of the access network, focusing on how calls are multiplexed in wired and wireless systems. Subsequently in the wireless case, we consider how to handover calls from 802.11 networks to the cellular infrastructure. We then consider the Internet backbone where most of our work is devoted to measurements specifically for Internet telephony. The applications of these measurements have been estimating telephony arrival processes, measuring call quality, and quantifying the trend in Internet telephony quality over several years. We also consider the end systems, since they are responsible for reconstructing a voice stream given loss and delay constraints. Finally we estimate voice quality using the ITU proposal PESQ and the packet loss process. The main contribution of this work is a systematic examination of Internet telephony. We describe several methods to enable adaptable solutions for maintaining consistent voice quality. We have also found that relatively small technical changes can lead to substantial user quality improvements. A second contribution of this work is a suite of software tools designed to ascertain voice quality in IP networks. Some of these tools are in use within commercial systems today

Simulating Road Traffic for Generating Cellular Network Logs in Urban Context

Viimastel aastatel on hakanud mobiilside andmestik paeluma aina rohkem teadlasi erinevatelt teadusdistsipliinidelt. Need andmed aitavad mõista inimeste käitumis- kui ka liikumismustreid. Mitmed mobiilsusandmestikud (nagu näiteks Call Detail Records mobiilside andmed) ning GPS andmed näitavad inimeste liikumissagedust ja -põhjusi.Need andmestikud sisaldavad endas väärtuslikku informatsiooni ühiskonna kohta. Töödeldud informatsiooni saab kasutada mitmel otstarbel. Teadlased saaksid andmestiku põhjal planeerida teedevõrgustikke, paremini suunata inimestele reklaame arvestades nende paiknemist, luua uusi positsioneerimistehnoloogiaid, arendada rahvastikukontrolli tarkvara jne.Vaatamata tehnoloogilistele võimalustele on inimeste mobiilsusandmestikud väga raskesti kättesaadavad, sest need on kaitstud riiklike regulatsioonide poolt, kuna riivavad inimeste privaatsust. Teine tegur on mobiilioperaatorite enda huvi luua inimeste mobiilsusandmetel põhinevaid kommertslahendusi. Selline situatsioon ei innusta operaatoreid jagama äriliselt vajalikku informatsiooni kolmandate osapooltega. Antud magistritöö käigus näidatakse, kuidas sellest raskest probleemist üle saada arendades mobiilsidevõrgukäitumissimulatsiooni prototüüpi. Genereerides andmeid läbi erinevate teaduslike liikumismudelite, mida võimaldab meile liiklussimulatsiooni tarkvara.Uurimistöö tulemusena selgus, et selline lähenemine on resultatiivne ja omab mitmeid laienemisvõimalusi. Täheldati mitmeid võimalusi koostööks teiste uurimisvaldkondadega, et muuta genereeritavaid mobiilsusandmeid reaalelule sarnanevateks. Mobiilsidevõrgu käituvussimulatsioon on näidanud suurt potentsiaali ning arendamise käigus avaldusid võimalused, mida algselt ei osatud oodata. Mainitud mobiilsidevõrgu käituvussimulatsioon on integreeritud eksisteeriva liiklussimulatsiooni tarkvaraga, mis on vabavara ning mida on võimalik laialdaselt konfigureerida. Liiklussimulatsiooni tarkvaraskasutatavad inimkäitumise mudelid põhinevad erinevate teadustööde tulemustel ning seetõttu mobiilsidevõrgu käituvus- ning liiklussimulatsiooni sümbioosi tulemusel genereeritud andmed on märkimisväärse väärtusega.In the last years, the use of mobile phone data logs start to attract a lot of researchers’ attentions from various disciplines. Those logs help the scientist to understand and predict human behaviour. The mobility logs, like Call Detail Records and GPS data, show where to people commute, how often do they commute and, usually, those logs also say why. These logs hold knowledge about our society, from that data the knowledge could be extracted and used for multiple purposes. The scientists could analyse through the movement how to plan the road infrastructure, generate target advertisement based on forecasting peoples displacement, new positioning technology, population control software, etc. But there are limits on the people's mobility data. Those information logs are heavily protected by the government privacy data laws to protect the personal rights. Additionally, the mobile operators are interested in their own commercial solutions and therefore their interest to share vital information is low. Here, in this thesis, we show that this cumbersome problem can be over-stepped by prototyping a cellular network behaviour simulator to generate the logs for us through different scientific commuting models inherited from the traffic simulation program.The result of this thesis reveals that this approach is feasible and shows multiple expansion possibilities how to produce even more real-life like mobility logs. The development of the cellular network behaviour simulation has shown huge potential and even bigger possibilities than predicted in the beginning. Since, our cellular network behaviour simulation is integrated with already existing open-source, highly configurable, road traffic simulator basing on the scientific human behaviour models produce with considerable value data

Multimedia delivery in the future internet

The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio and video are produced, distributed, shared, managed and consumed on-line through various networks, like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked challenges of the Networked Media in the transition to the Future of the Internet. Internet has evolved and changed the way we work and live. End users of the Internet have been confronted with a bewildering range of media, services and applications and of technological innovations concerning media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged that in a near- to mid-term future, the Internet will provide the means to share and distribute (new) multimedia content and services with superior quality and striking flexibility, in a trusted and personalized way, improving citizens’ quality of life, working conditions, edutainment and safety. In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and innovative applications “on the move”, like virtual collaboration environments, personalised services/ media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to contribute towards such a vision. Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6) and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way ahead in the area of Content Aware media delivery platforms