With the upcoming of the fifth generation of cellular networks there are several perfor- mance requirements that need to be satisfied. This thesis focuses on the topic of mobility which allows users to move through the network using the concept of handovers to switch between base stations. However, the thesis also keeps the energy efficiency in mind and investigates a strategy of reducing the energy consumption. Moving across base stations will inevitably lead to some handover failures, a goal of the system developers is to reduce these, but there exists a tradeoff between too early and too late handover failures. This thesis investigates two approaches of lowering the number of failures by letting the net- work self-optimize parameters in the handover procedure based upon the tradeoff. The first approach includes a parameter adaption to an estimated velocity of the users and the second one making a parameter more granular. Simulating different scenarios in a detailed network simulator shows performance gain by adapting handover parameters to the esti- mated velocity, but gathering more data regarding failures is needed before generalizing the conclusions.

Pour atteindre avec la 4G des débits théoriques supérieurs à 100 Mb/s et espérer pouvoir multiplier par 20 l’efficacité énergétique des futurs réseaux 5G, toute la richesse du canal de propagation doit être exploitée. Cet axe de recherche innovant d’optimisation de la couche physique de la communication se base sur la caractérisation multidimensionnelle « temps réel » du canal. Cette notion de "temps réel" signifie que toutes les dimensions spatiales (à l'émission et à la réception), temporelle, fréquentielle et polarimétrique seront explorées simultanément pour s'assurer des conditions de stationnarité du canal pendant la mesure. Le sondeur associé, objet de la thèse, doit également être capable de s’adapter à différents scénarii de propagation, y compris à un contexte de haute mobilité pour une liaison sol-sol entre trains à grande vitesse par exemple. Le système qui a ainsi été développé à l'aide de composants numériques programmables, fournit avec un temps de latence inférieur à quelques dizaines de µs et sans post traitement, 128 fonctions de transfert associées à un canal MIMO (8,16) dans 80 MHz de bande, la durée du signal transmis étant de 150 µs. Sa reconfigurabilité aisée lui confère l'originalité d'être multi fonctions pour s'adapter aux challenges à venir. Citons par exemple la cybersécurité des communications sans fil pour laquelle l'équipement aura les rôles de système de communication, de générateur d'interférences et de sondeur de canal.Dans le cadre de la localisation, via leur téléphone portable de personnes situées en forêt, les résultats des campagnes de mesures menées avec le sondeur soit au sol, soit embarqué dans un ULM, sont également décrits. / To be able to reach a bit rate higher than 100Mb/s with 4G systems and to multiply by 20 the energy efficiency of future 5G networks, all the propagation channel richness must be exploited. This innovative research area dealing with the physical layer optimization is based on the multidimensional channel characterization in "real time". This concept of “real time” means that space, time, frequency and polarimetric dimensions are explored simultaneously to ensure stationarity conditions of the channel during measurements. The channel sounder, subject of the thesis, must also be able to adapt to different scenarios of propagation, including a context of high mobility as, for example, in the case of a communication between high-speed trains. The system that has been developed, based on programmable digital components, allows measuring in a 80Mz bandwidth, 128 transfer functions associated with a (8,16) MIMO channel in less than a few tens of µs and without post-processing. The duration of the transmitted signal is 150 µs. Another originality of this sounder is its easy reconfigurability and its multi-function ability. For example, for studying cyber security of wireless communications, it would play the role of communication system, interference source and channel sounder. In the frame of localization of people in forest owing to their mobile phone, results of channel characterization conducted with the sounder placed either on the ground, or in an ULM, are also described and analyzed.

As the mobile Internet traffic increases, the workload of the base stations processing this traffic increases with it. To cope with this, the telecommunication providers responsible for the systems deployed in these base stations have looked to parallelism. This, together with the fact that these providers have a vested interest in protecting their users' data from potential attackers, means that there is a need for efficient parallel packet processing software which handles encryption as well as authentication. A well known protocol for encryption and authentication of IP packets is the Encapsulating Security Payload (ESP) protocol of the IPsec protocol suite. IPsec establishes simplex connections, called Security Associations (SA), between entities that wish to communicate. This thesis investigates a special case of this problem where the work of encrypting and authenticating the packets within a single SA is parallelized. This problem was investigated by developing and comparing two multi-threaded implementations based on the Eventdev, an event driven programming library, and ring buffer libraries of Data Plane Development Kit (DPDK). One additional Eventdev-based implementation was also investigated which schedules linked lists of packets, instead of single packets, in an attempt to reduce the overhead of scheduling packets to the worker cores. These implementations were then evaluated in terms of throughput, latency, speedup, and last level cache miss rates. The results showed that the ring buffer-based implementation performed the best in all metrics while the single packet-scheduling Eventdev-based implementation was outperformed by the one using linked lists of packets. It was shown that the packet generation, which was done by the receiving core, was the main limiting factor for all implementations. In addition, the memory resources such as the memory bus, memory controller and prefetching hardware were shown to likely be an area of contention and a possible bottleneck as the packet generation rate increases. The conclusion drawn from this was that a parallelized packet retrieval solution such as Receive Side Scaling (RSS) together with minimizing memory resource contention is necessary to further improve performance.

Doctor of Philosophy / Department of Electrical and Computer Engineering / Balasubramaniam Natarajan / The number of wireless devices is predicted to skyrocket from about 5 billion in 2015 to 25 billion by 2020. Therefore, traffic volume demand is envisioned to explode in the very near future. The proposed fifth generation (5G) of mobile networks is expected to be a mixture of network components with different sizes, transmit powers, back-haul connections and radio access technologies. While there are many interesting problems within the 5G framework, we address the challenges of energy-related management in a heterogeneous 5G networks. Based on the 5G architecture, in this dissertation, we present some fundamental methodologies to analyze and improve the energy efficiency of 5G network components using mathematical tools from optimization, control theory and stochastic geometry. Specifically, the main contributions of this research include: • We design power-saving modes in small cells to maximize energy efficiency. We first derive performance metrics for heterogeneous cellular networks with sleep modes based on stochastic geometry. Then we quantify the energy efficiency and maximize it with quality-of-service constraint based on an analytical model. We also develop a simple sleep strategy to further improve the energy efficiency according to traffic conditions. • We conduct a techno-economic analysis of heterogeneous cellular networks powered by both on-grid electricity and renewable energy. We propose a scheme to minimize the electricity cost based on a real-time pricing model. • We provide a framework to uncover desirable system design parameters that offer the best gains in terms of ergodic capacity and average achievable throughput for device-to-device underlay cellular networks. We also suggest a two-phase scheme to optimize the ergodic capacity while minimizing the total power consumption. • We investigate the modeling and analysis of simultaneous information and energy transfer in Internet of things and evaluate both transmission outage probability and power outage probability. Then we try to balance the trade-off between the outage performances by careful design of the power splitting ratio. This research provides valuable insights related to the trade-offs between energy-conservation and system performance in 5G networks. Theoretical and simulation results help verify the performance of the proposed algorithms.

To enable wireless control of factories, such that sensor measurements can be sent wirelessly to an actuator, the probability to receive data correctly must be very high and the time it takes to the deliver the data from the sensor to the actuator must be very low. Earlier, these requirements have only been met by cables, but in the fifth generation mobile network this is one of the imagined use cases and work is undergoing to create a system capable of wireless control of factories. One of the problems in this scenario is when all data in a packet cannot be sent in one transmission while ensuring the very high probability of reception of the transmission. This thesis studies this problem in detail by proposing methods to cope with the problem and evaluating these methods in a simulator. The thesis shows that splitting the data into multiple segments and transmitting each at an even higher probability of reception is a good candidate, especially when there is time for a retransmission. When there is only one transmission available, a better candidate is to send the same packet twice. Even if the first packet cannot achieve the very high probability of reception, the combination of the first and second packet might be able to. / För att möjliggöra trådlös kontroll av fabriker, till exempel trådlös sändning av data uppmätt av en sensor till ett ställdon som agerar på den emottagna signalen, så måste sannolikheten att ta emot datan korrekt vara väldigt hög och tiden det tar att leverera data från sensorn till ställdonet vara mycket kort. Tidigare har endast kablar klarat av dessa krav men i den femte generationens mobila nätverk är trådlös kontroll av fabriker ett av användningsområdena och arbete pågår för att skapa ett system som klarar av det. Ett av problemen i detta användningsområde är när all data i ett paket inte kan skickas i en sändning och klara av den väldigt höga sannolikheten för mottagning. Denna uppsats studerar detta problem i detalj och föreslår metoder för att hantera problemet samt utvärderar dessa metoder i en simulator. Uppsatsen visar att delning av ett paket i flera segment och sändning av varje segment med en ännu högre sannolikhet för mottagning är en bra kandidat, speciellt när det finns tid för en omsändning. När det endast finns tid för en sändning verkar det bättre att skicka samma paket två gånger. Även om det första paketet inte kan uppnå den höga sannolikheten för mottagning så kan kanske kombinationen av det första och andra paketet göra det.

Bandpass filters are an essential component of wireless communication systems that only transmits frequencies corresponding to the communication band and rejects all other frequencies. As the deployment of 5G draws nearer, first deployments are expected in 2020 [1], the need for viable filters at the new frequency bands becomes more imminent. Size and performance are two critical considerations for a filter that will be used in emerging mobile communication applications. The high frequency of 5G communication, 28 GHz as opposed to sub 6 GHz for nearly all previous communication protocols, means that previously utilized lumped component based solutions cannot be implemented since they are ill-suited for mm-wave applications. The focus of this work is the miniaturization of a high-performance filter. The Substrate Integrated Waveguide (SIW) is a high performance and promising structure and Low Temperature Co-Fired Ceramic (LTCC) is a high-performance material that both can operate at higher frequencies than the technologies used for previous telecommunication generations. To miniaturize the structure, a compact folded four-cavity SIW filter is designed, implemented and tested. The feeding structure is integrated into the filter to exploit the System on Package (SoP) attributes of LTCC and further reduce the total area of the filter individually and holistically when looking at the final integrated system. Two unique three dimensional (3D) integrated SoP LTCC two-stage SIW single cavity filters and one unique four-cavity filter all with embedded planar resonators are designed, fabricated and tested. The embedded resonators create a two-stage effect in a single cavity filter. The better single cavity design provides a 15% fractional bandwidth at a center frequency of 28.12 GHz, and with an insertion loss of -0.53 dB. The fabricated four-cavity filter has a 3-dB bandwidth of .98GHz centered at 27.465 GHz, and with an insertion loss of -2.66 dB. The designs presented highlight some of the previously leveraged advantages of SoP designs while also including additions of embedded planar resonators to feed the SIW cavity. The integration of both elements realizes a compact and high-performance filter that is well suited for future mm-wave applications including 5G.

Over the last couple of years, the world has witnessed an intensifying competition over 5G networks, triggered to a large extent but not exclusively by the geopolitical rivalry between the United States and China. To the backdrop of allegations that the Chinese government could force Chinese telecom company Huawei and ZTE to spy, sabotage or take other action's on Beijing's behalf, Washington ordered prompt restrictions on products from Huawei and pressured its allies to do the same. From a European perspective, Sweden stood out early as a country with a strong stance on 5G security by outright banning Chinese telecom providers Huawei and ZTE from taking part in Sweden's 5G frequency auction. This thesis seeks to understand how the securitising process of Sweden's 5G networks was initiated and evolved, through a comparative case study of the four main securitising actors' official discourses. Derived from previous studies on cybersecurity and securitisation, this thesis constructed an analytical framework tailored for the securitisation of 5G networks. The thesis is carried out as an idea analysis, looking for articulated threats pertaining to three distinct threat dimensions: 'network security', 'data and information protection' and 'China's assertiveness'. The analysis showed that all four...

This thesis deals with the topic of network slicing technology in 5G networks, mainly on the RAN part. In the theoretical part, basic principles of 5G network slicing in core network part and RAN part are presented. Practical part contains a simulation scenario created in NS3 simulator with LENA 5G module. Results of this simulation are presented and discussed with the emphasis on RAN slicing.

En aktör i ett nätverk kan verka som katalysator för att underlätta skapandet, sammanförandet och utvecklingen av ett nätverk. Kommunikationsbyrån Södra Tornet har i ett projekt tillsammans med Sandvik Coromant Gimo, Ericsson och Tele2 arbetat strategiskt för att sammanföra dessa aktörer kring ett gemensamt mål om teknisk innovation, mer specifikt implementeringen av 5G i en av Sandvik Coromant Gimos industrier. Syftet med uppsatsen är att kartlägga på vilket sätt de olika aktörerna bidragit med olika resurser under projektets olika steg och hur dessa resurser vävts samman och koordinerats. Studiens syfte uppnås genom att göra en fallstudie om projektet med hjälp av ett teoretiskt ramverk fokuserat kring organisations-och projektteori. Uppsatsen visar på hur olika aktörers heterogena resurser underlättat för projektets genomförande. Vidare visar uppsatsen hur tydlig samt effektiv kommunikation kan bidra till att förstå olika ingående aktörers behov. Detta underlättar för samarbetet inom ett nätverk.

Data centers requires a lot of energy due to that data centers count as the buildings also contains servers, cooling equipment, IT-equipment and power equipment. As the cooling solution for many data centers around the world right now, the compressor-based cooling solution counts for around 40% of the total energy consumption. A non-compressor-based solution that is used in some data centers, but also is in a research phase is the free cooling application. Free cooling means that the outside air is utilized to cool down the data center and there are two main technologies that contains within free cooling: airside free cooling and waterside free cooling. The purpose of this master thesis is to analyze two types of coils; one corrugated and the other one smooth, providing from Bensby Rostfria, to investigate if it is possible to use free cooling in 5G EDGE data center in Luleå, with one of these coils. The investigation will be done during the warmest day in summer. This because, according to weather data, Luleå is one candidate where this type of cooling system could be of use. The project was done through RISE ICE Datacenter where two identical systems was built next to each other with two corrugated hoses of different diameter and two smooth tubes with different diameter. The variables that was measured was the ambient temperature within the data hall, the water temperature in both water tanks, the temperature out from the system, the temperature in to the system and the mass flow of the air that was going to go through the system. The first thing that was done was to do fan curves to easier choose which input voltages for the fans that was of interest to do further analysis on. After that was done, three point was taken where the fan curve was of most increase. The tests were done by letting the corrugated hoses and smooth tubes to be in each of the water tanks and fill it with cold water. It was thereafter the coils that should warm the water from 4,75 °C – 9,75 °C, because of that the temperature in the data center was around 15 °C. The rising in particularly these temperatures was chosen because it is seen that to use free cooling the temperature differences must be at least 5 °C. The tests were done three times to get a more reliable result. All the data was further taken in to Zabbix and to further analysis in Grafana. When one test was done the files was saved from Grafana to Excel for compilation, and thereafter to Matlab for further analysis. The first thing that was analyzed was if the three different tests with the same input voltages gave similar results in the water temperature in the tank and the temperature out from the system. Thereafter, trendlines was built to investigate the temperature differences in and out of the system, the temperature differences in and the water temperature in the tank, the mass flow and the cooling power. That trendline was further in comparison to each other, which was 2D-plots between the cooling power and the temperature differences between the inlet and the water. Thereafter the both coils could compare to each other to see which of them that gave the largest cooling power and was most efficient to install in a future 5G data center module.  The conclusion for this master thesis is that the corrugated hose will give a higher cooling power with higher temperature differences outside, but during the warmest summer day it was distinctly the smooth tube that gave the largest cooling power and therefore the best result. The smooth tube also got, through hand calculations, the larger amount of pipe that was necessary to cool down the 5G module, but the smallest water tank. It was also shown that for the warmest summer day, a temperature in the water tank of 24 °C is the best, compared to 20 °C and 18 °C. The amount of coil that is needed to cool down the data center with a temperature in the water tank at 24 °C and how large the water tank differs between the two types of coils. For the corrugated hose a length of 1.8 km and a water tank of 9.4 m3. As for the smooth tube a length of 1.7 km and a water tank volume of 12 m3.  As can be seen throughout this project is that this type of cooling equipment is not the most efficient for the warmest summer day but could easily be used for other seasons.