No description available.

No description available.

Wireless Mesh Networks (WMNs) are bringing revolutionary change in the field of wireless networking. It is a trustworthy technology in applications like broadband home networking, network management and latest transportation systems. WMNs consist of mesh routers, mesh clients and gateways. It is a special kind of wireless Ad-hoc networks. One of the issues in WMNs is resource management which includes routing and for routing there are particular routing protocols that gives better performance when checked with certain parameters. Parameters in WMNs include delay, throughput, network load etc. There are two types of routing protocols i.e. reactive protocols and proactive protocols. Three routing protocols AODV, DSR and OLSR have been tested in WMNs under certain parameters which are delay, throughput and network load. The testing of these protocols will be performed in the Optimized Network Evaluation Tool (OPNET) Modeler 14.5. The obtained results from OPNET will be displayed in this thesis in the form of graphs. This thesis will help in validating which routing protocol will give the best performance under the assumed conditions. Moreover this thesis report will help in doing more research in future in this area and help in generating new ideas in this research area that will enhance and bring new features in WMNs. / Wireless Mesh Networks (WMNs) bringar revolutionerande förändring inom området för trådlösa nätverk. Det är en pålitlig teknik i tillämpningar såsom bredband hemma nätverk, nätverkshantering och senaste transportsystem. WMNs består av mesh routrar, kunder mesh och gateways. Det är en speciell typ av trådlöst ad-hoc-nätverk. En av frågorna i WMNs är resurshushållning som inkluderar routing och routing det finns särskilda routingprotokoll som ger bättre prestanda vid kontroll med vissa parametrar. Parametrar i WMNs omfatta dröjsmål, genomströmning, belastningen på nätet etc. Det finns två typer av routingprotokoll dvs reaktiva protokoll och proaktiva protokoll. Tre routingprotokoll AODV, DSR och OLSR har testats i WMNs under vissa parametrar som är försenade, genomströmning och belastningen på nätet. Testning av dessa protokoll kommer att utföras i den optimerade Network Evaluation Tool (OPNET) Modeler 14.5. De erhållna resultaten från OPNET kommer att visas i denna avhandling i form av grafer. Denna uppsats kommer att bidra till att godkänna vilka routingprotokoll kommer att ge bäst resultat enligt den antagna förhållanden. Dessutom kommer denna uppsats rapport kommer att bidra till att göra mer forskning i framtiden på detta område och bidra till att generera nya idéer inom detta forskningsområde som kommer att öka och att nya funktioner i WMNs. / +46762749245

The cellular networks are evolving to meet the future requirements of data rate,coverage and capacity. The fourth generation mobile communication system, LTEhas been developed to meet these goals. LTE uses multiple antenna features andlarger bandwidths in order to accomplish this task. These features will furtherextend the requirements of data rate, coverage, latency and flexibility. LTE also utilizes the varying quality of the radio channel and the interferencefrom other transmitters by adapting the data rate to the instantaneous channelquality at all the time. This is typically referred to as Link Adaptation. Thelink adaptation fails from time to time due to the varying channel quality as wellas the interference from other transmitters. In order to counteract these failures,retransmission methods are employed. These methods detect the errors on thereceiver side and signals the transmitter for the retransmission of the erroneousdata. The efficiency of link adaptation increases if combined with a properly designedretransmission scheme at the expense of delays due to retransmissions. This master thesis focuses on the study of the retransmission schemes with fasterfeedback, resulting in a reduction in delay. The feedback is generated by makingan early estimate of the decoding outcome and sending it early to the transmitterresulting in faster retransmission. This is important in certain applications wherethe data transmission is intolerant to delays.The thesis work shows by system performance simulations that fast packet retransmission,precisely called Early HARQ Feedback, significantly affects the systemperformance together with the utilization of the link adaptation. The study alsoshows that the link adaptation, in certain scenarios, can be optimized to improvethe system performance. In that respect, it is also possible to increase the numberof retransmissions within the same resource utilization. That optimization is basicallycalled aggressive link adaptation. Consequently, Early HARQ Feedback incombination with aggressive link adaptation provides a large improvement in thedownlink performance of the studied cases.

O principal objetivo deste trabalho é apresentar os aspectos de especificação e implementação dos serviços de transferência de arquivos desenvolvidos para duas redes locais, usadas em ambientes de automação industrial e de automação de escritório, respectivamente. São apresentados, inicialmente, alguns conceitos e os requisitos de especificação que devem ser satisfeitos por estes serviços. À luz desta caracterização, algumas especificações de serviços de transferência de arquivos para redes de computadores são estudadas e analisadas. De acordo com esta análise e com as tendências de padronização de redes de computadores usadas nas aplicações acima mencionadas, é escolhida uma especificação a ser tomada como base na implementação destes serviços. Estes serviços são especificados detalhadamente, considerando as características das redes locais utilizadas. Alguns aspectos de implementação da máquina de protocolo que presta os serviços especificados são discutidos, descrevendo-se o conjunto de processos que constituem tal máquina. Em seguida, são especificados os programas aplicativos desenvolvidos a partir destes serviços de transferência de arquivos, considerando-se os requisitos das aplicações envolvidas. Para avaliar o sistema implementado, alguns testes são definidos, visando verificar a operacionalidade, conformidade e desempenho deste sistema. Os resultados destes test6es são apresentados e discutidos. Finalmente, são feitas considerações sobre o sistema implementado e a especificação tomada como base. Como continuidade do presente trabalho, é sugerida a implementação de outros serviços utilizando a infra-estrutura criada pelo mesmo. / The main purpose of this work is to present aspects on the specification and the implementation of the file transfer services, developed for two local area networks used in manufacturing and office automation. Some concepts and the specification requirements for such services are initially presented. In the light of this introduction some specifications of file transfer services for computer networks are studied and analyzed. Based on this analysis and on the trends in computer networks standardization for the above mentioned applications, a specification is selected as the basis for the file transfer services. These services are then fully specified taking into account the characteristics of the target local area networks. Some implementation aspects of protocol machine which provides the specified services are discussed describes the processes that make up such machine. The application programs developed using these file transfer services are then described. Some tests are conceived the verify the functionalism, conformity and performance of the implemented system. The results of these tests are presented and discussed in some detail. Finally, some considerations on the implemented system and the specification used as basis are presented. As future work the implementation of other services using the framework created is suggested.

O principal objetivo deste trabalho é apresentar os aspectos de especificação e implementação dos serviços de transferência de arquivos desenvolvidos para duas redes locais, usadas em ambientes de automação industrial e de automação de escritório, respectivamente. São apresentados, inicialmente, alguns conceitos e os requisitos de especificação que devem ser satisfeitos por estes serviços. À luz desta caracterização, algumas especificações de serviços de transferência de arquivos para redes de computadores são estudadas e analisadas. De acordo com esta análise e com as tendências de padronização de redes de computadores usadas nas aplicações acima mencionadas, é escolhida uma especificação a ser tomada como base na implementação destes serviços. Estes serviços são especificados detalhadamente, considerando as características das redes locais utilizadas. Alguns aspectos de implementação da máquina de protocolo que presta os serviços especificados são discutidos, descrevendo-se o conjunto de processos que constituem tal máquina. Em seguida, são especificados os programas aplicativos desenvolvidos a partir destes serviços de transferência de arquivos, considerando-se os requisitos das aplicações envolvidas. Para avaliar o sistema implementado, alguns testes são definidos, visando verificar a operacionalidade, conformidade e desempenho deste sistema. Os resultados destes test6es são apresentados e discutidos. Finalmente, são feitas considerações sobre o sistema implementado e a especificação tomada como base. Como continuidade do presente trabalho, é sugerida a implementação de outros serviços utilizando a infra-estrutura criada pelo mesmo. / The main purpose of this work is to present aspects on the specification and the implementation of the file transfer services, developed for two local area networks used in manufacturing and office automation. Some concepts and the specification requirements for such services are initially presented. In the light of this introduction some specifications of file transfer services for computer networks are studied and analyzed. Based on this analysis and on the trends in computer networks standardization for the above mentioned applications, a specification is selected as the basis for the file transfer services. These services are then fully specified taking into account the characteristics of the target local area networks. Some implementation aspects of protocol machine which provides the specified services are discussed describes the processes that make up such machine. The application programs developed using these file transfer services are then described. Some tests are conceived the verify the functionalism, conformity and performance of the implemented system. The results of these tests are presented and discussed in some detail. Finally, some considerations on the implemented system and the specification used as basis are presented. As future work the implementation of other services using the framework created is suggested.

Att skydda sin information mot offline-attacker och stöld kan vara önskvärt, därför kan man använda sig utav filsystemskryptering. Den här studien är en prestandatestning av de tre olika kryptoprogrammen BestCrypt, BitLocker och DiskCryptor, som krypterar filsystemet. Resultaten syftar till att ge en fingervisning av vilket kryptoprogram man bör välja. Detta tydliggjordes när testerna visade att filsystemskryptering påverkar responsen hos Apache och FileZilla och att de påverkades olika mycket beroende av kryptoprogram. / To protect data against offline-attacks and theft, which might be desirable, one can encrypt the filesystem. This study is a performance test of the three different encryption programs BestCrypt, BitLocker and DiskCryptor. Results of the study aims to give a pointer to which encryption program one should choose. This was clear when the tests showed that the encryption affected the response of the services Apache and Filezilla and that they were affected differently depending on which encryption program that was used.

Kuriama programinė įrangą sumaniesiems telefonams naudos bylų siuntimo protokolą – FTP. Ji leis vartotojui nuotoliniu būdu naršyti interneto tiekėjo talpyklos ir namų kompiuterio katalogus taip pat paprastai kaip ir sumaniojo telefono vidinės atminties katalogus. Kuriama programinė įranga taip pat leis vartotojams labiau išnaudoti sumaniųjų telefonų galimybes bei skatins programinės įrangos, skirtos darbui su įvairiomis bylomis vartojimą. Darbo tikslas - sukurti FTP protokolą naudojančią programinę įrangą, skirtą sumaniesiems telefonams, leisiančią naršyti nutolusių bylų talpyklų katalogus ir patogiai siųsti bylas. Darbe analizuozajama analogiška programinė įranga, nagrinėjamos J2ME programavimo kalbos galimybės, FTP protokolo veikimas. Tyrimo objektas – sukurti FTP protokolą naudojančią klientinę programinę įrangą, skirtą sumaniesiems telefonams. Darbe pateikiama programinės įrangos sudėtis, reikalavimai programinei įrangai, statiniai bei dinaminiai kuriamos sistemos vaizdai, testavimo rezultatai, prototipo vartotojo dokumentaija. / In recent years smart phones became efficient enough to run many aplications. Their endless posibilities are only limited by the lack of software. New smart phones lack of good software to download files, as a result downloading files using internet connection is inconveniant. The aim of this job is to build software which is able to use FTP to download files from home or public servers. Achieving this goal required analysis of exsicting software, user needs, specification of requirements. Abstract system model was made using UML diagrams. Software was developed using J2ME programming language. Testing software alowed to repair errors and optimize its work. Developed software could be used as additional value for smart phone users from internet providers. J2ME language alows to do easy updates and modifications to software. Newest JM2E technology and additional optional packages allowed to develope fast working and easy to use software.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The CCSDS SCPS FP file transfer performance is compared with that of TCP/IP FTP in a simulated satellite channel environment. The comparison is made as a function of channel bit error rate and forward/return data rates. From these simulations, we see that both protocols work well when the channel error rate is low (below 10^-6) and the SCPS FP generally performs better when the error rate is higher. We also noticed a strong effect on the SCPS FP throughput as a function of forward transmission rate when running unbalanced channel tests.

4G LTE is a new cellular phone network standard to provide both the capacity and Quality of Service (QoS) needed to support multimedia applications. Recent research in LTE has explored modifications to the current QoS setup, creating MAC layer schedulers and modifying the current QoS architecture. However, what has not been fully explored are the effects of LTE retransmission choices and capabilities on QoS. This thesis examines the impact of using acknowledgments to recover lost data over the wireless interface on VoIP, FTP and MPEG video applications. Issues explored include interaction between application performance, network transport protocols, LTE acknowledgment mode, and wireless conditions. Simulations show that LTE retransmissions improve FTP throughput by 0.1 to 0.8 Mb/s. With delay sensitive applications, like VoIP and video, the benefits of retransmissions are dependent on the loss rate. When the wireless loss rate is less than 20%, VoIP has similar performance with and without LTE retransmissions. At higher loss rates the use of LTE retransmissions adds degrading the VoIP quality by 71%. With UDP video, the choice of retransmissions or not makes little change when the wireless loss rates are less than 10%. With higher wireless loss rates, the frame arrival delay increases by up to 539% with LTE retransmissions, but the frame rate of the video decreases by up to 34% without those retransmissions. LTE providers should configure their networks to use retransmission policies appro- priate for the type of application traffic. This thesis shows that VoIP, FTP and video require different configurations in the LTE network layers.