IP Mobility in Wireless Operator Networks

Wireless network access is gaining increased heterogeneity in terms of the types of IP capable access technologies. The access network heterogeneity is an outcome of incremental and evolutionary approach of building new infrastructure. The recent success of multi-radio terminals drives both building a new infrastructure and implicit deployment of heterogeneous access networks. Typically there is no economical reason to replace the existing infrastructure when building a new one. The gradual migration phase usually takes several years. IP-based mobility across different access networks may involve both horizontal and vertical handovers. Depending on the networking environment, the mobile terminal may be attached to the network through multiple access technologies. Consequently, the terminal may send and receive packets through multiple networks simultaneously. This dissertation addresses the introduction of IP Mobility paradigm into the existing mobile operator network infrastructure that have not originally been designed for multi-access and IP Mobility. We propose a model for the future wireless networking and roaming architecture that does not require revolutionary technology changes and can be deployed without unnecessary complexity. The model proposes a clear separation of operator roles: (i) access operator, (ii) service operator, and (iii) inter-connection and roaming provider. The separation allows each type of an operator to have their own development path and business models without artificial bindings with each other. We also propose minimum requirements for the new model. We present the state of the art of IP Mobility. We also present results of standardization efforts in IP-based wireless architectures. Finally, we present experimentation results of IP-level mobility in various wireless operator deployments.

A Decentralized Session Management Framework for Heterogeneous Ad-Hoc and Fixed Networks

Wireless technologies are continuously evolving. Second generation cellular networks have gained worldwide acceptance. Wireless LANs are commonly deployed in corporations or university campuses, and their diffusion in public hotspots is growing. Third generation cellular systems are yet to affirm everywhere; still, there is an impressive amount of research ongoing for deploying beyond 3G systems. These new wireless technologies combine the characteristics of WLAN based and cellular networks to provide increased bandwidth. The common direction where all the efforts in wireless technologies are headed is towards an IP-based communication. Telephony services have been the killer application for cellular systems; their evolution to packet-switched networks is a natural path. Effective IP telephony signaling protocols, such as the Session Initiation Protocol (SIP) and the H 323 protocol are needed to establish IP-based telephony sessions. However, IP telephony is just one service example of IP-based communication. IP-based multimedia sessions are expected to become popular and offer a wider range of communication capabilities than pure telephony. In order to conjoin the advances of the future wireless technologies with the potential of IP-based multimedia communication, the next step would be to obtain ubiquitous communication capabilities. According to this vision, people must be able to communicate also when no support from an infrastructured network is available, needed or desired. In order to achieve ubiquitous communication, end devices must integrate all the capabilities necessary for IP-based distributed and decentralized communication. Such capabilities are currently missing. For example, it is not possible to utilize native IP telephony signaling protocols in a totally decentralized way. This dissertation presents a solution for deploying the SIP protocol in a decentralized fashion without support of infrastructure servers. The proposed solution is mainly designed to fit the needs of decentralized mobile environments, and can be applied to small scale ad-hoc networks or also bigger networks with hundreds of nodes. A framework allowing discovery of SIP users in ad-hoc networks and the establishment of SIP sessions among them, in a fully distributed and secure way, is described and evaluated. Security support allows ad-hoc users to authenticate the sender of a message, and to verify the integrity of a received message. The distributed session management framework has been extended in order to achieve interoperability with the Internet, and the native Internet applications. With limited extensions to the SIP protocol, we have designed and experimentally validated a SIP gateway allowing SIP signaling between ad-hoc networks with private addressing space and native SIP applications in the Internet. The design is completed by an application level relay that permits instant messaging sessions to be established in heterogeneous environments. The resulting framework constitutes a flexible and effective approach for the pervasive deployment of real time applications.

Analysis of Heterogeneous IP Traffic in Wireless Environment

Wireless access is expected to play a crucial role in the future of the Internet. The demands of the wireless environment are not always compatible with the assumptions that were made on the era of the wired links. At the same time, new services that take advantage of the advances in many areas of technology are invented. These services include delivery of mass media like television and radio, Internet phone calls, and video conferencing. The network must be able to deliver these services with acceptable performance and quality to the end user. This thesis presents an experimental study to measure the performance of bulk data TCP transfers, streaming audio flows, and HTTP transfers which compete the limited bandwidth of the GPRS/UMTS-like wireless link. The wireless link characteristics are modeled with a wireless network emulator. We analyze how different competing workload types behave with regular TPC and how the active queue management, the Differentiated services (DiffServ), and a combination of TCP enhancements affect the performance and the quality of service. We test on four link types including an error-free link and the links with different Automatic Repeat reQuest (ARQ) persistency. The analysis consists of comparing the resulting performance in different configurations based on defined metrics. We observed that DiffServ and Random Early Detection (RED) with Explicit Congestion Notification (ECN) are useful, and in some conditions necessary, for quality of service and fairness because a long queuing delay and congestion related packet losses cause problems without DiffServ and RED. However, we observed situations, where there is still room for significant improvements if the link-level is aware of the quality of service. Only very error-prone link diminishes the benefits to nil. The combination of TCP enhancements improves performance. These include initial window of four, Control Block Interdependence (CBI) and Forward RTO recovery (F-RTO). The initial window of four helps a later starting TCP flow to start faster but generates congestion under some conditions. CBI prevents slow-start overshoot and balances slow start in the presence of error drops, and F-RTO reduces unnecessary retransmissions successfully.

How Can Sustainable Agricultural Systems Promote Food Security in a Changing Climate?

A theoretical framework of the link between climate change, rural development, sustainable agriculture, poverty, and food security is presented. Some options to respond to climate change are described. Current knowledge and potential effects on agricultural productivity is discussed. Necessary conditions for successful adaptation includes secured property rights to land, institutions that make market access possible and credit possibilities. The options of mitigation and enhanced adaptive capacity and the requirements for their implementation are discussed.

The Art of Adaptation : A study on the Europeanization of Finland's foreign and security policy

This study examines how Finnish foreign and security policy has been influenced by the European Union and its Common Foreign and Security Policy. It points to a growing interplay and misfit between the external expectations originating from the European level and the domestic expectations and traditional ways-of-doing-things. It is concluded that the deepening European integration in the sphere of foreign, security and defence policy has played a significant role in a number of transformations in the Finnish policies since 1995. New, more European, meanings have been attached to the key concepts of Finnish foreign and security policy. Neutrality and traditional peacekeeping have been replaced by a minimalist reading of military non-alignment and participation in crisis management operations and EU battle groups. Traditional small state identity has been recast more and more as small member stateness . At the same time Finland has entered an era of post-consensus in national foreign and security policy. A key theoretical argument in the background of the study is that collective understandings attached to European policies, when not resonating well with domestic understandings, cause adaptation pressures on domestic-level processes and may lead to changes in the way interests and identities are constructed. This means that Europeanization is principally seen as identity reconstruction. Consequently, the theoretical framework of the study builds on the Europeanization research literature and constructivist IR theory on state identity. Foreign and security policy is defined as the practice in which state identity is reproduced, and the key foreign and security policy concepts are seen as the vehicles of identity production. It is concluded that for Finland, participation in the EU s foreign, security and defence policies represents not only a tool for responding to the changes in the international security environment but also a new means of self-identification. Concerning the Finnish attempts of projecting national interests on the European security policy agenda, it is concluded that they mainly relate to the compatibility of the potential development of EU s defence dimension with the Finnish military non-alignment. Although neutrality was cast aside in the official security policy when Finland joined the EU, the analysis shows that its impact has continued in the domestic political debate and in the mind-set of the decision-makers. The primary research material includes official Finnish foreign and security policy documentation and the related parliamentary debates from 1994 to 2007. This study serves also as a comprehensive empirical overview on Finland s reactions and contributions to the EU Common Foreign and Security Policy.

Baltic Sea : security tomorrow - three future scenarios

Aineisto on Keskustakampuksen kirjaston digitoimaa ja kirjasto vastaa aineiston käyttöluvista.

Impact of agricultural market liberalization on food security in developing countries : a comparative study of Kenya and Zambia

This research investigates the impacts of agricultural market liberalization on food security in developing countries and it evaluates the supply perspective of food security. This research theme is applied on the agricultural sector in Kenya and in Zambia by studying the role policies played in the maize sub-sector. An evaluation of selected policies introduced at the beginning of the 1980s is made, as well as an assessment of whether those policies influenced maize output. A theoretical model of agricultural production is then formulated to reflect cereal production in a developing country setting. This study begins with a review of the general framework and the aims of the structural adjustment programs and proceeds to their application in the maize sector in Kenya and Zambia. A literature review of the supply and demand synthesis of food security is presented with examples from various developing countries. Contrary to previous studies on food security, this study assesses two countries with divergent economic orientations. Agricultural sector response to economic and institutional policies in different settings is also evaluated. Finally, a dynamic time series econometric model is applied to assess the effects of policy on maize output. The empirical findings suggest a weak policy influence on maize output, but the precipitation and acreage variables stand out as core determinants of maize output. The policy dimension of acreage and how markets influence it is not discussed at length in this study. Due to weak land rights and tenure structures in these countries, the direct impact of policy change on land markets cannot be precisely measured. Recurring government intervention during the structural policy implementation period impeded efficient functioning of input and output markets, particularly in Zambia. Input and output prices of maize and fertilizer responded more strongly in Kenya than in Zambia, where the state often ceded to public pressure by revoking pertinent policy measures. These policy interpretations are based on the response of policy variables which are more responsive in Kenya than in Zambia. According the obtained regression results, agricultural markets in general, and the maize sub-sector in particular, responded more positively to implemented policies in Kenya, than in Zambia, which supported a more socialist economic system. It is observed in these results that in order for policies to be effective, sector and regional dimensions need to be considered. The regional and sector dimensions were not taken into account in the formulation and implementation of structural adjustment policies in the 1980s. It can be noted that countries with vibrant economic structures and institutions fared better than those which had a firm, socially founded system.

Actuarial report 2011: Social security schemes administered by Kela 2010-2060

Projections concerning the long-term outlook of the social security schemes administered by the Social Insurance Institution of Finland (Kela) are made regularly by the Institution’s Actuarial Section. The report at hand was compiled with the help of an aggregate model devised by the Actuarial Section. In the model, various universal factors influencing benefit trends are consolidated and the interactions between individual benefits are taken into account. The demographic forecasts underlying the report have also been made by the Actuarial Section. Estimates of income and administrative costs have been made in cooperation with the Financial Planning Section.

Paradox between democracy and security- case study on Pakistan

Pro gradu-tutkielma tutkii demokratian ja turvallisuuden paradoksia Pakistanissa esitellen kuusi tekijää, jotka vaikuttavat kyseiseen paradoksiin. Näitä tekijöitä ovat historiallinen kehitys; eliittihallinto; taloudellinen kehitys; Pakistanin poliittisten tekijöiden demokratian eri määritelmät; opetuksen puuttuminen; ja valtataistelu hallituksen, armeijan, tiedustelupalvelun, oikeusjärjestelmän, poliittisten puolueiden sekä eri heimojen, uskonnollisten ja etnisten ryhmien välillä. Tutkimus tarkastelee myös sitä miten nämä tekijät vaikuttavat demokratian kehitykseen Pakistanissa. Keskeinen argumentti on, että länsimainen demokratia ei esiinny eikä toimi Pakistanissa vallitsevissa oloissa, etenkin historiallisen kehityksen ja ulkoisen turvallisuuden takia. Pro gradu-tutkielma käyttää sekundäärisiä lähteitä, kuten kirjoja, artikkeleita, maaraportteja, kommentaareja sekä omiin kokemuksiin perustuvia havaintoja Pakistanin matkalta 2010-2011. Keskeiset teoriat gradussa ovat Guillermo O’ Donnelin delegaattidemokratia sekä Duncan McCargon eliittihallintoteoria, jotka yhdessä selittävät historiallista kehitystä ja eliittihallinnon dynamiikkaa, mitkä johtavat paradoksiin. Kautta historian armeija on hallinnut Pakistania, ja siviilihallinto on ainoastaan neljä kertaa onnistunut olemaan vallassa, mutta silloinkin siviilihallinto päättyi korruptioväitteisiin tai armeijan vallankaappaukseen. Armeijahallinnoille on luonteenomaista hyvät suhteet USA:n, positiivinen taloudellinen kehitys ja vakaus, kun taas siviilihallinnot ovat epävakaita ja korruptoituneita. Tämä kehitys on paradoksin tausta, joka rakentuu turvallisuuspoliittisen tilanteen pohjalle eli hallitusten ja muiden tekijöiden yritykseen löytää vastapaino Intian uhalle. Tämä on ollut keskeinen huoli kelle tahansa poliittiselle päättäjälle itsenäisyydestä lähtien. Loputon valtataistelu eri poliittisten tekijöiden kesken sekä eliittihallinto pitävät yllä paradoksia, koska eliitit ovat kiinnostuneempia oman valtansa säilyttämisestä kuin kansan tahdon huomioonottamisesta. Koska valtaosa ihmisistä ei ole koulutettuja, he ovat paljolti kiinnostuneita omasta selviytymisestään, ja tämän takia sekä kansa että eliitit suosivat armeijahallintoa, koska se tuo vakautta ja taloudellista kehitystä. Sen vuoksi vallitsevissa oloissa demokratian tulevaisuus Pakistanissa näyttää huonolta, koska liberaalidemokratian vaatimukset eivät täyty puoliksi vapaan oikeussysteemin, puoliksi vapaan lehdistön, valtavan korruption ja monien ihmisoikeusloukkauksien takia unohtamatta armeijan ja tiedustelupalvelun sekaantumista siviilihallintoon.