As technology moves forward it has a tendency to consume more and more power that needs to be cooled by bigger and louder fans, this is especially true for the new generation of 5G radio equipment. This Master thesis is a collaboration with Ericsson and attempts to construct a shroud for containing a number of 5G radio units whilst attenuating the fan noise of the units as effectively as possible. In this project are air ducts used and at the ends silencers are created utilizing the Cremer impedance; the optimal wall impedance for damping an acoustic mode of a propagating wave. To predict the result, a simplified model in an acoustic FEM program was also explored and compared to the sound level of the constructed shroud. The finished shroud successfully reduces the noise of the radio units by 13 dB(A) while causing an increase in temperature of between 2.8°C to 5.9°C. This result was deemed to be a success and the Cremer impedance approach of reducing noise is therefore advised for future development. / Allt eftersom tekniken går framåt tenderar den att också förbruka mer och mer energi som i sin tur måste kylas av kraftigare och mer högljudda fläktar, detta fenomen är särskilt påtagligt när det kommer till den senaste generationens radioutrustning för 5G. Detta examensarbete är ett samarbete mellan KTH och Ericsson med avsikt att skapa en kåpa som är designad för att innesluta ett bestämt antal 5G radiomoduler. Denna kåpa ska i så stor utsträckning som möjligt dämpa det fläktinducerade bullret. I det här projektet nyttjas kanaler med ljuddämpare vid ändarna som dämpar ljudet med hjälp av Cremerimpedans, dvs: den väggimpedans som optimalt dämpar en akustisk mod. För att kunna förutspå resultatet skapades en förenklad akustisk modell i ett FEM program. Resultatet från denna modell jämförs sedan med ljudeffektnivån från slutmätningen av den färdiga kåpan. Resultatet från slutmätningen visar att kåpan lyckas sänka radioenheternas totala ljudeffektnivå med 13 dB(A) samtidigt som en temperaturökning på mellan 2.8°C och 5.9°C erhålls. Det här resultatet bedöms vara en framgång, vilket leder till slutsatsen att ljuddämpning med användning av Cremerimpedans rekommenderas för vidare arbete.

In a wireless communication system, synchronization is one of the most critical functions. Good timing and synchronization can prevent messages of the communication system from interfering with each other and enable a smooth message transfer. For 5G (the fifth generation of telecommunication network), the timing and synchronization requirements are even more strict. To synchronize the communication system, the first thing is to detect the connection quality and find the faults’ positions. This thesis aims to investigate a machine learning or deep learning approach to predict the connection quality called ”Hearability” between cells and to find the base stations whose cells have an absolute time error larger than a configurable threshold. The results show that the random forest classifier can obtain the highest accuracy while requiring less computing time than k-Nearest-Neighbors, Support Vector Machine, and Graph Neural Network. Additionally, we found the base stations with faults and offered suggestions for detecting the faults in complicated cases. / I ett trådlöst kommunikationssystem är synkronisering en av de mest kritiska funktionerna. Bra timing och synkronisering kan förhindra meddelanden från kommunikationssystemet från att störa varandra och möjliggöra en smidig meddelandeöverföring. För 5G (den femte generationens telekommunikationsnätverk) är kraven på timing och synkronisering ännu strängare. För att synkronisera kommunikationssystemet är det första att detektera anslutningskvaliteten och hitta felens positioner. Denna avhandling syftar till att undersöka en maskininlärning eller djupinlärning för att förutsäga anslutningskvaliteten som kallas ”Hörbarhet” mellan celler och att hitta de basstationer vars celler har ett absolut tidsfel som är större än en konfigurerbar tröskel. Resultaten visar att den slumpmässiga skogsklassificeraren kan få högsta noggrannhet samtidigt som den kräver mindre beräkningstid än k-Nearest-Neighbors, Support Vector Machine och Graph Neural Network. Dessutom hittade vi basstationerna med fel och gav förslag för att upptäcka felen i komplicerade fall.

The differences between legacy and 5G networks in both capability, and their increasingly dynamic nature and complexity warrant searching for new kinds of ways to manage networks. This thesis work explored different options for interaction and interfaces for a declarative, intent-based control (IBC) based 5G network management system. IBC has not been previously applied on the transport layer and in addition to drafting interface concepts, this work also maps existing definitions and implementations of IBC and intents. The functioning of IBC on the transport layer was envisioned through these existing solutions. The work was done as an iterative codesign project following a user-centered design process. Concepts were both drafted and evaluated together with a group of domain experts. Special attention was paid to the forming of trust towards automation. A tentative task path for issuing an intent to the system was mapped and the drafted concepts approached the steps involved in the task path with varying levels of automation and different visual representations for the information the user needs and the functions of the system. No prior body research exists on IBC on the transport layer and trust towards automation in network management and the topics are novel. The envisioned application of IBC on the transport layer, and the drafted concepts on user interaction with the system are tentative in nature and more research is required to determine the feasibility of applying IBC on the transport layer, as well as the effectiveness of the presented concepts in promoting trust among users. / Skillnaderna mellan äldre och 5G-nätverk i båda funktionerna, och deras alltmer dynamiska karaktär och komplexitet motiverar sökning efter nya typer av sätt att hantera nätverk. Detta avhandlingsarbete undersöktes olika alternativ för interaktion och gränssnitt för en deklarativ, avsiktsbaserad kontroll (intent-based control, IBC) 5G-nätverkshanteringssystem. IBC har inte tidigare applicerats på transportskiktet och förutom utarbetande av gränssnittskoncept, kartlägger detta arbete också befintliga definitioner och implementeringar av IBC och avsikter. Funktion av IBC på transportskiktet förutsågs genom dessa befintliga lösningar. Arbetet gjordes som ett iterativt samdesignprojekt efter den användarcentrerad designprocess. Begrepp utarbetades och utvärderades tillsammans med en grupp domenexperter. Särskild uppmärksamhet ägnas åt bildandet av förtroende för automatisering. En preliminär arbetsväg för att utfärda en avsikt till systemet kartlades och de utarbetade koncepten närmade sig stegen i uppgiftsvägen med varierande nivåer av automatisering och olika visuella representationer för informationen användarens behov och systemets funktioner. Ingen tidigare undersökning finns på IBC på transportskit och förtroendet mot automatisering i nätverkshantering och ämnena är nya. De förutsåg tillämpning av IBC på transportlagret och utkastet begrepp om användarinteraktion med systemet är preliminära och mer forskning krävs för att bestämma genomförbarheten av att tillämpa IBC på transportskiktet, liksom effektiviteten på det presenterade begrepp för att främja förtroende bland användare. / 5G verkkojen eroavaisuudet aikaisempiin verkkoihin niin dynaamisuuden, kuin uusien kyvykkyyksien ja verkkojen monimutkaisuus vaativat uudenlaisia tapoja hallita verkkoja. Työssä konseptoitiin eri vuorovaikutus- ja käyttöliittymämalleja aiepohjaiselle- (intent-based control, IBC), deklaratiiviselle hallintamallille 5G-verkkojen hallintaan. IBC:ia ei ole aikaisemmin sovellettu kuljetusverkkotasolla ja käyttöliittymämallien lisäksi työssä kartoitettiin myös IBC:in ja aikeen (intent) olemassa olevia määritelmiä ja toteutustapoja sovellustasolla, joiden pohjalta hahmoteltiin, miten IBC toimisi kuljetusverkkotasolla. Työ toteutettiin osallistavana, iteratiivisena muotoiluprojektina seuraten käyttäjäkeskeistä suunnitteluprosessia. Konseptit luotiin, sekä arvioitiin pienessä ryhmässä alan asiantuntijoiden kanssa. Luottamuksen muodostamiseen automaatiota kohtaan kiinnitettiin erityistä huomiota. Työstetyissä konsepteissa käyttäjän toimintopolun eri askeleita aikeen antamiseksi järjestelmälle lähestyttiin eri kanteilta vaihdellen toimintopolun automatisaation tasoa, sekä verkon ja aikeen tilan ja toimintojen käyttäjälle näkyvää visuaalista esitystä. IBC:n soveltaminen kuljetusverkkotasolla ja luottamus automaatiota kohtaan verkonhallinnassa ovat aiheina uusia, eikä aiheista löydy aikaisempaa tutkimusmateriaalia. Työn hahmotelma IBC:ista kuljetusverkkotasolla, sekä työn aikana tuotetut konseptit käyttäjän vuorovaikutuksesta järjestelmän kanssa ovat luonteeltaan alustavia ja lisää tutkimustyötä vaaditaan mm. IBC:n käytön realistisuudesta kuljetusverkkotasolla, sekä hahmoteltujen konseptien toimivuudesta käyttäjän luottamuksen vahvistamisessa.

Internet of Things (IoT) is an ecosystem comprises CT (Communication Technology),IT (Information Technology) and sometime OT (Operational Technologies) wheredifferent machines and devices can interact with each other and exchange useful datawhich can be processed using different IoT applications to take decisions and performrequired actions. Number of IoT devices and IoT networks are growing exponentially.Security is of utmost importance and without proper security implementation, IoTNetworks with billions of devices will be hacked and used as botnets which can createdisaster. The new IoT use cases cannot be realized using the current communicationtechnologies due to the QoS (Quality of Service) and business requirements. 5Gnetwork are designed keeping IoT use cases in mind and with the development of 5Gnetwork, it will be easier to implement more secured IoT network and enable differentIoT use cases which are not feasible today.To build the future IoT networks with 5G, it’s important to study and understand 5Gsecurity features. Security is perceived as one of the most important considerationwhile building IoT solutions and to implement 5G network for IoT solutions require anoverall understanding of 5G security features. In the thesis, work have been done toidentify the gap in the current research with respect to 5G security features anddescribe 5G features that will enhance IoT security. After identifying key 5G securityfeatures, the implementation of the identified 5G security features will be describedwith the 5G based smart grid and smart factory use cases. The key finding is howdifferent 5G security capabilities secure IoT communication and another importantfinding is that not all security capabilities are applicable to all IoT use cases. Hence,security capabilities to be used based on the 5G use case requirement.

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.

In today’s society the ability to communicate with one another has grown, were a lot of focus is aimed towards speed in the telecommunication industry. For transmissions to become even faster, there are many ways to enhance transmission speeds of which error correction is one. Padding messages such that they are protected from noise, while using as few bits as possible and ensuring safe transmit is handled by error correction codes. Short codes with low complexity is a solution to faster transmission speeds. An error correction code which has gained a lot of attention since its first appearance in 2009 is Polar Codes. Polar Codes was chosen as the 3GPP standard for 5G control channel. The goal of the thesis is to develop and implement Polar Codes and rate matching according to the 3GPP standard 38.212. Polar Codes are then to be evaluated with different block sizes and rate matching settings. Finally Polar Code is compared with Convolutional code in a LTE-simulation environment. The performance evaluations are presented using BLER/(Eb/N0)-graphs. In this thesis a Polar encoder, rate matching and a Polar decoder (with Successive Cancellation algorithm) were successfully implemented. The simulation results show that Polar Codes performs better with longer block sizes and also has a better BLER-performance than Convolutional Codes when given the same message lengths.

The deployment of heterogeneous networks (HetNets), in which low power nodes (LPNs) and high power nodes (HPNs) coexist, has become a promising solution for extending coverage and increasing capacity in wireless networks. Meanwhile, several advanced technologies such as massive multi-input multi-output (MIMO), cloud radio access networks (C-RAN) and device-to-device (D2D) communications have been proposed as competent candidates for supporting the next generation (5G) network. Since single technology cannot solely achieve the envisioned 5G requirements, the e ect of integrating multiple technologies in one system is worth to be investigated. In this thesis, a thoroughly theoretical analysis is conducted to evaluate the network performance in di erent scenarios, where two or more 5G techniques are employed. First, the downlink performance of massive MIMO enabled HetNets is fully evaluated. The exact and asymptotic expressions for the probability of a user being associated with a macro cell or a small cell are presented. The analytical expressions for the spectrum e ciency (SE) and energy e ciency (EE) in the K-tier network are also derived. The analysis reveals that the implementation of massive MIMO in the macro cell can considerably improve the network performance and decrease the demands for small cells in HetNets, which simpli es the network deployment. Then, the downlink performance of a massive MIMO enabled heterogeneous C-RAN is investigated. The exact expressions for the SE and EE of the remote radio heads (RRHs) tier and a tractable approximation approach for evaluating the SE and EE of the macrocell tier are obtained. Numerical results collaborate the analysis and prove that massive MIMO with dense deployment of RRHs can signi cantly enhance the performance of heterogeneous C-RAN theoretically. Next, the uplink performance of massive MIMO enabled HetNets is exploited with interference management via derived SE and EE expressions. The numerical results show that the uplink performance in the massive MIMO macrocells can be signi cantly improved through uplink power control in the small cells, while more uplink transmissions in the macrocells have mild adverse e ect on the uplink performance of the small cells. In addition, the SE and EE of the massive MIMO macrocells with heavier load can be improved by expanding the small cell range. Lastly, the uplink performance of the D2D underlaid massive MIMO network is investigated and a novel D2D power control scheme is proposed. The average uplink achievable SE and EE expressions for the cellular and D2D are derived and results demonstrate that the proposed power control can e ciently mitigate the interference from the D2D. Moreover, the D2D scale properties are obtained, which provide the su cient conditions for achieving the anticipated SE. The results demonstrate that there exists the optimal D2D density for maximizing the area SE of D2D tier. In addition, the achievable EE of a cellular user can be comparable to that of a D2D user. Stochastic geometry is applied to model all of the systems mentioned above. Monte Carlo simulations are also developed and conducted to validate the derived expressions and the theoretical analysis.

One important feature of the future communication network is that users in the network are required to experience a guaranteed high quality of service (QoS) due to the popularity of multimedia applications. This thesis studies QoS-aware radio resource management schemes in different OFDMA network scenarios. Motivated by the fact that in current 4G networks, the QoS provisioning is severely constrained by the availability of radio resources, especially the scarce spectrum as well as the unbalanced traffic distribution from cell to cell, a joint antenna and subcarrier management scheme is proposed to maximise user satisfaction with load balancing. Antenna pattern update mechanism is further investigated with moving users. Combining network densi fication with cloud computing technologies, cloud radio access network (C-RAN) has been proposed as the emerging 5G network architecture consisting of baseband unit (BBU) pool, remote radio heads (RRHs) and fronthaul links. With cloud based information sharing through the BBU pool, a joint resource block and power allocation scheme is proposed to maximise the number of satisfi ed users whose required QoS is achieved. In this scenario, users are served by high power nodes only. With spatial reuse of system bandwidth by network densi fication, users' QoS provisioning can be ensured but it introduces energy and operating effciency issue. Therefore two network energy optimisation schemes with QoS guarantee are further studied for C-RANs: an energy-effective network deployment scheme is designed for C-RAN based small cells; a joint RRH selection and user association scheme is investigated in heterogeneous C-RAN. Thorough theoretical analysis is conducted in the development of all proposed algorithms, and the effectiveness of all proposed algorithms is validated via comprehensive simulations.

In the cellular networks, to support the increasing data rate requirements, many base stations (BSs) with low transmit power and small coverage area are deployed in addition to classical macro cell BSs. Low power nodes, such as micro, pico, and femto nodes (indoor and outdoor), which complement the conventional macro networks, are placed primarily to increase capacity in hotspots (such as shopping malls and conference centers) and to enhance coverage of macro cells near the cell boundary. Combining macro and small cells results in heterogeneous networks (HetNets). An accurate node (BS or user equipment (UE)) model is important in the research, design, evaluation, and deployment of 5G HetNets. The distance between transmitter (TX), receiver (RX), and interferer determines the received signal power and interference signal power. Therefore, the spatial placement of BSs and UEs greatly impacts the performance of cellular networks. However, the investigation on the spatial distribution of UE is limited, though there is ample research on the topic of the spatial distribution of BS. In HetNets, UEs tend to cluster around BSs or social attractors (SAs). The spatial distribution of these UEs is non-uniform. Therefore, the analysis of the impact of non-uniformity of UE distribution on HetNets is essential for designing efficient HetNets. This thesis presents a non-uniform user distribution model based on the existing K-tier BS distribution. Our proposed non-uniform user distribution model is such that a Poisson cluster process with the cluster centers located at SAs in which SAs have a base station offset with their BSs. There are two parameters (cluster radius and base station offset) the combination of which can cover many possible non-uniformity. The heterogeneity analysis of the proposed nonuniform user distribution model is also given. The downlink performance analysis of the designed non-uniform user model is investigated. The numerical results show that our theoretical results closely match the simulation results. Moreover, the effect of BS parameters of small cells such as BS density, BS cell extension bias factor, and BS transmit power is included. At the same time, the uplink coverage probability by the theoretical derivation is also analyzed based on some simplifying assumptions as a result of the added complexity of the uplink analysis due to the UEs’ mobile position and the uplink power control. However, the numerical results show a small gap between the theoretical results and the simulation results, suggesting that our simplifying assumptions are acceptable if the system requirement is not very strict. In addition to the effect of BS density, BS cell extension bias factor, and BS transmit power, the effect of fractional power control factor in the uplink is also introduced. The comparison between the downlink and the uplink is discussed and summarized at the end. The main goal of this thesis is to develop a comprehensive framework of the non-uniform user distribution in order to produce a tractable analysis of HetNets in the downlink and the uplink using the tools of stochastic geometry

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.