The aim of this Masters Thesis project is to give the Swedish National Post and Telecom Agency, Post- och Telestyrelsen (PTS), an updated view on I P Telephony relative to the Swedish consumer market. The basic questions were raised by PTS and the focus is on the relevant topics from the agency’s point of view. PTS is primarily interested in understanding what state IP Telephony is in and furthermore what IP Telephony can be used for in practice. What are the possibilities of different implementations and what will be their advantages and disadvantages? Despite being on the scene for many years, IP Telephony is now on the verge of a break through. With the creation of gateways between IP and PSTN, various IP Telephony devices, and with the introduction of SIP (described in RFC2543) as a standard signalling protocol, perhaps today, IP Telephony has a significant potential on the consumer market. Many argue that 2003 will be the year that IP Telephony blossoms. The fact that anyone can be their own operator, the role of the traditional operator versus the new operators, the separation of content and signalling transmission, as well as the efficient use of bandwidth are some of the topics covered in this report.</p> Due to the introduction of The Electronic Communications Act that comes into effect the 25th of July 2003, replacing The Telecommunications Act and The Radiocommunications Act, much of the focus in this report lies on regulatory issues. However, in order to get an insight in to the regulatory issues it is important to understand the underlying technology of IP Telephony as well as areas such as security, robustness, privacy, and emergency calls. Through a market analysis, an updated overview of the market for IP Telephony will be given, along with plausible future scenarios. This report will provide the reader with answers not by focusing on the theoretical details of the technology itself, but rather in terms of it’s practical use and limitations. / Syftet med denna rapport är att ge Post- och Telestyrelsen (PTS) en uppdaterad bild av den svenska IP-telefonimarknaden för privatpersoner. Då examensarbetet utfördes för PTS togs de grundläggande frågeställningarna fram av myndigheten och fokus för examensarbetet lades således på ämnen relevanta för PTS. Trots att IP-telefoni har varit på tapeten i flera år, har tekniken ännu inte haft sitt genombrott på privatmarknaden. Existensen av slussar mellan IP och PSTN, samt utvecklingen av IP-telefoniutrustning och standardiserade protokoll (såsom SIP beskriven i RFC2543), har givit IP-telefoni förutsättningen att ta en signifikant roll på den svenska privatmarknaden. Många anser att 2003 är året då IP-telefoni kommer att ha sitt genombrott. Utvecklingen och ändringen av den traditionella operatörsrollen, separationen av signaltrafik och samtalstrafik samt den effektiva och variabla användningen av bandbredd, är några av de faktorer som ger upphov till spännande frågeställningar. Introduktionen av lagen för elektronisk kommunikation som träder i kraft den 25 Juli 2003, och ersätter både telelagen och lagen om radiokommunikation, har gjort att fokus till stor del riktas på de regulativa frågorna inom området. För att sätta sig in i dessa regulativa frågor krävs dock god insikt i tekniken bakom IP-telefoni samt förståelse i områden såsom säkerhet, robusthet, QoS och nödsamtal. En marknadsanalys bidrar med en uppdaterad bild av marknaden för IP-telefoni samt möjliga framtidscenarion. Rapporten förser läsaren med svar genom att fokusera på teknikens praktiska användning och begränsningar snarare än att fokusera på de teoretiska detaljerna.

Bluetooth is a low cost, short-range radio technology that enables electronic devices to communicate wirelessly via ad-hoc networks. Different kinds of applications may run over these networks, some of these applications with particular Quality of Service (QoS) requirements. One such application could for instance be an Audio application which need data frames to be delivered at regular interval to work properly. The communication over Bluetooth links is totally controlled by one of the participating nodes. Since this node controls the traffic and thereby controls the QoS within the network its communicating behaviour is of great importance for maintaining QoS reservations. A central part in maintaining QoS reservations is the scheduler, which prioritises between different tasks to be done such as which device that is allowed to transmit next. There is no standardised way to implement the Bluetooth scheduler. However, a Bluetooth scheduler should be able to handle QoS reservations, maintain fairness among the participating nodes, and utilise the available bandwidth efficiently. Furthermore a key requirement in Bluetooth is simplicity, therefore a Bluetooth scheduling algorithm should be of low complexity. This master thesis presents a new patented solution for an intra-piconet scheduling algorithm that is capable of maintaining QoS reservation, while being fair and also meet the low complexity requirement. This algorithm is presented in detail in the thesis and has been implemented in an ns2- based Bluetooth simulator. Simulations in this simulator are presented that verifies the scheduling algorithms functionality. / Bluetooth är en standard för trådlös ad-hoc kommunikation. Denna standard definierar i antalet noder begränsade nätverk (piconet) som kan kopplas samman till större nätverk (scatternet). Många olika typer av applikationer kan tänkas använda dessa nätverk, vissa av dessa med speciella krav på Quality of Service (QoS). Ett exempel så en dylik applikation är ljudöverföringar som kräver att data överförs med jämna mellanrum för att kunna fungera tillfredställande. Kommunikationen över ett Bluetooth-piconet kontrolleras helt av en av de deltagande enheterna. Eftersom denna enhet kontrollerar trafiken kontrollerar den också upprätthållandet av QoS reservationerna. En central del i detta upprätthållande är schemaläggaren, som är den del i en Bluetoothenhet som prioriterar mellan olika saker som ska utföras. Ett exempel på en sådan prioritering kan vara vilken enhet i nätverket som ska få kommunicera härnäst. Bluetooth standarden beskriver inte hur denna schemaläggare ska implementeras. Grundläggande krav på en Bluetooth schemaläggare är att den ska kunna hantera och upprätthålla QoS reservationer samtidigt som den delar den befintliga kapaciteten på ett rättvist och effektivt sätt mellan de deltagande enheterna. Vidare bör den ha en låg komplexitet eftersom enkelhet är ett krav på alla delar i ett Bluetoothsystem. Detta examensarbete presenterar en ny patenterad algoritm för schemaläggning i begränsade Bluetoothnät som är kapabel att upprätthålla QoS-reservationer, samtidigt som den distribuerar den tillgängliga kapaciteten på ett rättvist sätt. Algoritmen möter också upp till kravet på låg komplexitet. Rapporten innehåller vidare simuleringar av algoritmens funktion, dessa har utförts i en ns2-baserad Bluetooth miljö och verifierar algoritmens funktionalitet.

Context information available in wearable devices is believed to be useful in many ways. It allows for hiding much of the complexity from the user, thus enabling simpler user interfaces and less user interaction when carrying out tasks on behalf of a user, as well as enabling network operators to provide a better interface to thirdparty service providers who will provide and deliver wireless services. Using the available context information from the wearable device, optimization of service delivery in wireless networks, such as setting up optimal delivery paths between two wearable devices, may be possible without using a third party to do negotiations. In order to fully enable context-awareness, a clear model for how to sense, manage, derive, store, and exchange context information must be defined. This will then provide the platform needed to enable development of context-aware applications that can exploit the possibilities of context-aware computing. The model must take into consideration parameters such as memory usage and power and bandwidth consumption, in order to be efficient on all types of platforms and in all types of networks. It must also be modular enough to survive replacing and upgrading of internal parts. Today little research is available about sensing context information, sensor management, APIs towards other applications, and how and how often to present context information to applications. Since context aware computing relies heavily on the ability to obtain and represent context information, sensing strategies greatly affect efficiency and performance. It is therefore of great interest to develop and evaluate models for carrying out these tasks in order to exploit the results of context awareness research. This thesis will identify and design several components of such a model, as well as test and evaluate the design, in order to be able to make conclusions to whether is lives up to the expectations stated. In order to make the proper design decisions, a full understanding of the context-awareness research area and the goals and purposes of context-aware computing are required. To understand the entire picture is crucial to find a suitable solution. Therefore, determining an efficient sensor input and management strategy, along with a powerful and flexible API for applications, which are the goals of this thesis, fully qualifies as a significant master thesis assignment. / Information om bärbara enheters omgivning som kan göras tillgänglig i enheten, tros kunna vara användbart på många sätt. Det kan möjliggöra gömmande av komplexitet från användaren, vilket ger enklare användargränssnitt och mindre användarinteraktivitet, när utförandet av uppdrag från användaren sker, eller underlätta för en nätverksoperatör som tillhandahåller ett bättre gränssnitt gentemot en tredje part, som tillhandahåller och levererar trådlösa tjänster. Genom att utnyttja tillgänglig information om omgivningen från en bärbar enhet, kan man optimera leverans av tjänster i trådlösa nätverk, så som att hitta en optimal kommunikationsväg mellan två bärbara enheter, utan att använda sig av förhandlingar med en tredje part. För att till fullo möjliggöra ett sådant omgivningsmedvetande, krävs en tydlig modell för att uppfatta, förfina, lagra och utbyta det data som beskriver omgivningen. Denna modell kan då utgöra en plattform som möjliggör utveckling av omgivningsmedvetande applikationer, som kan utnyttja och reagera på de data som beskriver omgivningen. Modellen måste ta hänsyn till parametrar så som minneskonsumtion och batteri- och bandbreddsförbrukning, för att vara effektiv på alla typer av plattformar och i alla typer av nätverk. Den måste också bestå av tillräckligt väl separerade moduler för att klara av byten och uppgraderingar av dess beståndsdelar. Idag finns endast lite tillgänglig forskning om insamlandet av omgivningsdata, hanteringen av sensorer, gränssnitt gentemot mot applikationer och hur och hur ofta omgivningsdata skall presenteras för applikationer. Eftersom omgivningsmedvetenhet beror av möjligheten att införskaffa och representera omgivningsdata, påverkar strategier för att uppfatta omgivningen både effektivitet och prestanda. Det finns därför ett stort intresse i att utveckla och utvärdera modeller för utförandet av dessa uppdrag och för att utforska forskningsresultat om omgivningsmedvetande. Denna rapport identifierar och konstruerar flera komponenter till en sådan modell, samt testar och utvärderar denna för att kunna dra slutsatser om huruvida den lever upp till de förväntningar som finns. För att kunna göra en fullgod konstruktion, krävs en ingående förståelse i forskningsområdet omgivningsmedvetande och syften och mål med densamma. Att förstå den övergripande bilden är nyckeln till en passande lösning. Konstruktion av effektiva strategier för att uppfatta omgivningen, tillsammans med ett kraftfullt och flexibelt API gentemot applikationer, vilket är målen med denna rapport, kvalificerar sig därför som ett examensarbete.

The Transmission Control Protocol (TCP), used in the Internet, was not developed for a mobile, wireless environment. One reason why TCP might encounter problems in such an environment is rapid changes of the link characteristics. These rapid changes can occur due to handover between two subnetworks (macro handover), e.g., when a mobile node switches between different access networks. A possible and realistic handover scenario could be when a mobile node is roaming between a high bandwidth local area network (LAN) with limited coverage and a low bandwidth radio link with wide area coverage. The goals of this thesis were to set up a realistic environment for measurements of the handover performance of TCP, and to observe TCP behavior when the link characteristics suddenly change. Further objectives were to analyze the results and propose solutions for improving the performance. The mobility management in the measurement setup is handled by Mobile IP. Handovers are performed between a wireless LAN (WaveLAN) and a PPP link over a GSM circuit switched data connection. Our investigation shows that several spurious TCP timeouts occur after handover from the fast link to the slow link, triggering unnecessary retransmissions and hence resulting in TCP performance degradation. To avoid unnecessary retransmissions, we suggest a resetting of the retransmission timeout value (RTO) at the moment of handover. In the case of handover from the low bandwidth link (PPP) to the high bandwidth link (WaveLAN), our measurements show that queued packets in the link layer buffer continue to flow over the PPP link even after the handover. The high bandwidth available after the switch is thus poorly utilized before the buffer of the low bandwidth link has been emptied. The IP sending process should delay putting packets in the queue of a slow link, thus avoiding large link layer queues and enabling utilization of the high bandwidth link faster. This could be achieved by flow control between the IP layer and the link layer. After the packets have started flowing over the WaveLAN, the RTO value is unnecessarily high, which could result in extensive delays in the case of packet losses. To alleviate the problems we recommend resetting the RTO value or modifying the algorithm for calculating the RTO value to faster adapt to sudden and significant decrease of the round-trip time (RTT) in the case of handover. In both handover scenarios mentioned above we have found that a small window size is favorable to mitigate the negative effects due to the rapid changes of the link characteristics. The use of Active Queue Management to avoid large window sizes would be an interesting approach for future investigations. Another interesting approach could be to have flow control between the IP layer and the link layer to avoid a large link layer queue when the handover from [one link to another occurs.]

Multiport beam splitter is a new research topic in quantum communication. To improve the security system, the dimension/capacity of quantum communication should increase. In this thesis, design, simulation and methodology of NXN multiport beam splitter on a photonic integrated circuit is explained. Photonic integrated circuit has more advantages than other optical components to design a multiport beam splitter. Multiport beam splitter on a photonic chip gives configuration stability, a compact prototype for future quantum network.

The increasing heterogeneity of communicating devices, ranging from resource constrained battery driven sensor nodes to multi-core processor computers, challenges protocol design. We examine security and privacy protocols with respect to exterior factors such as users, adversaries, and computing and communication resources; and also interior factors such as the operations, the interactions and the parameters of a protocol. Users and adversaries interact with security and privacy protocols, and even affect the outcome of the protocols. We propose user mobility and adversary models to examine how the location privacy of users is affected when they move relative to each other in specific patterns while adversaries with varying strengths try to identify the users based on their historical locations. The location privacy of the users are simulated with the support of the K-Anonymity protection mechanism, the Distortion-based metric, and our models of users' mobility patterns and adversaries' knowledge about users. Security and privacy protocols need to operate on various computing and communication resources. Some of these protocols can be adjusted for different situations by changing parameters. A common example is to use longer secret keys in encryption for stronger security. We experiment with the trade-off between the security and the performance of the Fiat–Shamir identification protocol. We pipeline the protocol to increase its utilisation as the communication delay outweighs the computation. A mathematical specification based on a formal method leads to a strong proof of security. We use three formal languages with their tool supports in order to model and verify the Secure Hierarchical In-Network Aggregation (SHIA) protocol for Wireless Sensor Networks (WSNs). The three formal languages specialise on cryptographic operations, distributed systems and mobile processes. Finding an appropriate level of abstraction to represent the essential features of the protocol in three formal languages was central. / <p>QC 20170217</p> / ProFuN

No description available.

Localization of mobile devices has implications on a multitude of use cases such as estimating the location of the user originating an emergency call, localization of devices to enable autonomous operation required by industrial Internet of Things (IoT) use cases, etc. In futuristic use cases such as Augmented Reality (AR), Virtual Reality (VR), Extended Reality (XR), autonomous navigation of Unmanned Aerial Vehicles (UAVs), we will require the capability of estimating orientation in addition to position of such devices for efficient and effective provisioning of these services to the end-users. One way to handle the problem of finding the orientation of devices is to rely on the measurements from different sensors like the magnetometer, accelerometer and gyroscope but the limitation of this method is the dependency on these sensors, and thus cannot be used for some devices which does not have these sensors. Hence these limitations can be overcome by using data-driven approaches like Machine Learning (ML) algorithms on received signal features, where a training dataset with orientation measurements are used to train the ML model that can transform the received signal measurements to orientation estimates. The data for the work is generated by using simulator that can simulate the environment with multiple base stations and receivers. The measurements or features that are generated from the simulator are the Received Signal Received Power (RSRP), Time of Arrival (ToA), Line of Sight (LoS) condition, etc. In-order to find the relationship between the received signal features and orientation, two nonlinear ML algorithms namely K Nearest Neighbors (KNN) and Random Forest (RF) are used. The received measurements were investigated and RSRP was identified as the feature for the ML models. The ML algorithms are able to estimate the orientation of the User Equipment (UE) by using KNN and RF, where different features likes RSRP and the information about LoS and Non Line of Sight (NLoS). These features were used alone and also combined to evaluate the performance. The results also shows how interference of radio signals affects the performance of the model. Adding to that, different combination of received signal features were also used to compare the performance of the model. Further tests were also done on the trained model to identify how well it can estimate orientation when a new UE with new position is introduced.

Abstract—This paper will detail the process and methods to the problem with having an Offline Certificate Authority that can still be accessed remotely. Specifically, to update CRL on the server when the need arises without bringing the entire CA online. This has been managed via local access in the past but to ease the use a need for remote management has arisen. This paper will explain how this problem was solved with the use of a Data diode to prevent the CA to be fully online. A Data Diode will only allow traffic in one direction keeping any data from leaking from the CA while still making it available for specific uploads, in this case CRL files that handle the revocation of certificates issued by the CA. This will allow for more up to date lists when the server is brought online for the issuance of certificates once per year. This paper will try to detail the steps that need to be taken in order to set up an edge server that allows the transmission of files with the use of UDP.  Keywords—CRL Content Revocation List, CA Certificate Authority, Data Diode, Offline Server, UDP user Datagram Protocol.

Virtual Private LAN Service (VPLS) networks have emerged as a popular solution for providing scalable and efficient Layer 2 connectivity across wide-area networks. However, designing secure and scalable VPLS networks presents significant challenges. The full-mesh tunneling approach in HIP-based VPLS networks results in the N square scalability problem. This thesis addresses the scalability issue in HIP-based Virtual Private LAN Service (VPLS) networks by introducing relay routers. An optimization model based on the Capacitated Facility Location Model is proposed to select the optimal relay routers for a given network topology. The objective of the model is to minimize the cost of setting up and maintaining relay routers while ensuring proper network operation. The proposed solution is evaluated using Software-Defined Networking (SDN) and Mininet-based simulations. The results show that the proposed approach is effective in reducing the scalability issue in HIP-based VPLS networks.