Cars and other automobiles are used for transportation every single day all over the world. Almost ninety percent of the households have access to at least one car. Along with this, the chance of getting into an accident has also risen. Our objective is to deal with the case of parking. Everyone must have felt anxiety about the distances while sitting inside the car. Oneway or the other way, it always leads to property damage, etc. It will be difficult for people who spend lavish money on their vehicles to see the damage. In our project, we designed a system that aids drivers with information about distances between the vehicle and a wall or obstacle. It will be even more helpful if the driver has an idea of the distance between the wall and the vehicle by visual representation not as a text because of natural instinct. A hardware setup is fixed to the walls of the garage after analyzing all the possible scenarios including skewed parking which only guides the driver. This system uses sensors like ultrasonic to get information about the distances and an LED strip to guide the driver about the distances. Depending on the distances the LED will indicate either red or green and also the number of glowing LEDs. The two signals to the LED are pre-calibrated after considering the garage spacing. This system can effectively remove the chance of accidents while parking a vehicle in the garage.

As 5G and O-RAN become more widely used, the number of user equipment requesting access to the network will increase. This will require operators to expand their 5G solutions by purchasing more hardware to handle the increase in demand. The acquisition of new hardware will have both an economic and an environmental impact. Hardware is costly for operators, both in initial cost and when operating it. There is also a significant energy cost associated, which has a negative environmental impact.     This thesis explores the benefits of more advanced control over the path taken within the Radio Access Network, with the goal of increasing the number of user equipment able to connect to a static set of hardware. The control comes from new algorithms designed with the intuition that providing connections with only the bare essentials and nothing more would, in theory, increase the capacity of the whole network. Three algorithms were tested, with one representing a basic control method of selecting the first valid connection, and the other two were built on the intuition of the worst acceptable connection.     The three algorithms were tested on four different shapes of network configuration at four different sizes. The tests were run on a graph data structure implemented in C++ that represents the logical paths a connection could take. This resulted in a noticeable improvement in networks that exhibited a triangular structure, with more units as one moved toward the edge of the network. The largest improvement observed managed to fit 18.9% more units into the network.

This Licentiate presents the main results of theoretical study of light propagation in photonic structures, namely lasing disk microcavities and photonic crystals. In the first two papers (Paper I and Paper II) we present the developed novel scattering matrix technique dedicated to calculation of resonant states in 2D disk microcavities with the imperfect surface or/and inhomogeneous refractive index. The results demonstrate that the imperfect surface of a cavity has the strongest impact on the quality factor of lasing modes. The generalization of the scattering-matrix technique to the quantum-mecha- nical case has been made in Paper III. That generalization has allowed us to treat a realistic potential of quantum-corrals (which can be considered as nanoscale analogues of optical cavities) and to obtain a good agreement with experimental observations. Papers IV and V address the novel effective Green's function technique for studying propagation of light in photonic crystals. Using this technique we have analyzed characteristics of surface modes and proposed several novel surface-state-based devices for lasing/sensing, waveguiding and light feeding applications. / <p>Report code: LIU-TEK-LIC 2006:5</p>

A rising level of industrialization and advances in Industry 4.0 have resulted in Industrial Internet of Things (IIoT) gaining immense significance in today’s industrial automation systems. IIoT promises to achieve improved productivity, reliability, and revenues by connecting time-constrained embedded systems to “the Internet”. New opportunities bring with them challenges, and in particular for industrial networks, massively interconnected IIoT devices communicating in real-time,  require synchronized operation of devices for the ordering of information collected throughout a  network. Thus,   a   time or clock synchronization service that aligns the devices’ clocks in the network to ensure accurate timestamping and orderly event executions, has gained great importance. Achieving adequate clock synchronization in the industrial domain is challenging due to heterogeneous communication networks and exposure to harsh environmental conditions bringing interference to the communication networks. The investigative study based on existing literature and the envisioned architecture of the future industrial automation system unveils that the key requirements for future industrial networks are to have a cost-effective, accurate, scalable, secured, easy to deploy and maintain clock synchronization solution. Today’s industrial automation systems employ clock synchronization solutions from a wide plethora of hardware and software based solutions. The most economical, highly scalable, maintainable software-based clock synchronization means are best candidates for the identified future requirements as their lack in accuracy compared to hardware solutions could be compensated by predictive software strategies.  Thus, the thesis’s overall goal is to enhance the accuracy of software-based clock synchronization in heterogeneous industrial networks using predictable software strategies. The first step towards developing an accurate clock synchronization for heterogeneous industrial networks with real-time requirements is to investigate communication parameters affecting time synchronization accuracy. Towards this goal, we investigated actual industrial network data for packet delay profiles and their impact on clock synchronization performance.  We further analyzed wired and wireless local area networks to identify key network parameters for clock synchronization and proposed an enhanced clock synchronization algorithm CoSiNeT for field IoT devices in industrial networks. CoSiNeT matches well with state-of-the-practice SNTP and state-of-the-art method SPoT in good network conditions in terms of accuracy and precision;  however,  it outperforms them in scenarios with degrading network conditions.

This master thesis aims for Inter-carrier interference (ICI) mitigation in orthogonal frequency division multiplexing (OFDM) system by considering designs of frequency domain cyclic extension(FDCE) and optimal windowing pulse shape. Although OFDM system has been put forward in the 1970s, it has just emerged in 4G. In the early stage, it has been restricted by its high computational complexity. With the discovery that modulation and demodulation process of OFDM can be realized by discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT), it is widely used in 4G and 5G-New Ratio (NR). Based on OFDM system, a variety of derivative systems are further proposed and applied. With the development of 5G technology in the mobile communication, the requirement of signal propagation between high-speed mobile user and base station (BS) is higher and higher. With the increase of the moving speed of objects, the frequency shift caused by Doppler eff ect can not be underestimated. ICI caused by Doppler shift is becoming more and more serious. Therefore, how to eliminate the ICI caused by Doppler shift has become an inevitable potential problem. In this thesis, two eff ective approaches for ICI mitigation have been explored and studied. By adding FDCE and optimal windowing pulse shape, the system performance is analyzed and the system simulation is constructed in MATLAB.

The purpose of this thesis rose from tackling a specific project led by Cybercom Group. Water Sense was proposed after municipalities expressed the need to conveniently conduct measurements on water in Swedish lakes, and remotely get access to these data. The varying and infrequent nature of measurements result in an inefficient power consumption when a conventional sensor platform is used. Internet of Things is a relatively new and ever-evolving field for wireless sensor networks, where Low Power Wide-Area Network protocols are utilized to cleverly save power. One of these LPWAN protocols is LoRaWAN, a MAC layer protocol that runs on top of the PHY layer protocol LoRa. The chosen platform hardware for sensor nodes is an Adafruit feather equipped with a LoRa radio module, and the Contiki operative system was to be imported and integrated. Contiki OS is developed for small IoT systems with low-power, while offering networking mechanisms and a range of protocols typically utilized in WSNs. The adaptive and modular nature of Contiki allows for custom pairing of protocols to target a specific topology. LoRaWAN has a number of constraints that are disadvantageous for Water Sense, most prominently being a single-hop protocol. Contiki already supports several platforms with drivers, but the CPU and radio module of the Adafruit feather are not one of them. The goal was to integrate the LoRa PHY hardware with Contiki and have an adaptive platform for Water Sense and other scenarios. Unfortunately not all initial goals were achieved, and the physical layer was not fully integrated with Contiki’s APIs. However, the drivers needed for an operational physical layer were completed and range test could be conducted. Therefore, this thesis details the work done for implementing the physical layer and a study on Contiki’s data link protocols in proposed configurations for Water Sense.

Reconfigurable intelligent surface (RIS) is a promising technology for wireless communications applications. A RIS is a thin planar array that consists of multiple reflecting elements, each of which is connected to a tunable chip and can induce a controllable reflection coefficient to the incident signal. The RIS is a nearly passive unit as it only leverages the reflection on its elements and it does not consume any power for transmission. Furthermore, RISs can actively control the propagation channel, by accurately tuning the reflection coefficients of their elements to fit a specific need. The advantage of the RIS arises in creating energy-efficient smart radio environments wherein the wireless channel becomes an optimization variable. In this thesis, we study some of the potential applications and deployments for the RIS in wireless communications. First, the multiple-input multiple-output channel matrix in line-of-sight (LoS) environments turns out to be rank deficient such that spatial multiplexing becomes unattainable. Thus, we exploit the RISs to create additional degrees of freedom by synthesizing a sort of multi-path propagation. Then, we optimize the transmit covariance matrix and the reflection coefficients of the RISs using an alternating optimization algorithm to maximize the achievable rate. Alternatively, we propose different schemes to enhance the composite channel power which would result in an improvement to the achievable rate. Second, we characterize the efficient regions of RIS deployments with single and multiple antenna systems in Rician fading channels. We show that in RIS-aided single antenna systems, near RIS deployments relative to the transmitter or receiver are always better than far deployments. Moreover, we show that in RIS-aided multiple antenna systems, the efficient regions of operations are highly dependent on the propagation environment itself. In LoS environments, both the near and far deployments can result in substantial achievable rate gains. However, as the channel becomes richer with multipath, near deployments gradually become more efficient than the far deployments. Third, we propose the RIS to act as an access point for information transfer by exploiting the polarization control ability of the RIS. In particular, the RIS alternates the polarization state of the reflected waves to perform conventional as well as differential polarization shift keying (PolSK) modulation schemes. In RIS-aided conventional PolSK, two different schemes are proposed. In the first scheme, the receiver corrects for the polarization mismatch loss that occurs in the wireless channel. In the second scheme, the RIS additionally pre-codes the reflected wave to compensate for the polarization mismatch. In RIS-aided differential PolSK, the detection process is independent of the polarization mismatch. Thus, there is no need for a polarization mismatch compensation process by either the receiver or the RIS.

The 3rd generation partnership program (3GPP) has in recent years started working on integratingnon-terrestrial networks (NTN) into the 5G eco-system. This thesis focuses on the mobility between NTN and TN, which is of great importance if 5G NTN is to provide seamless and limitless connectivity. The target of this thesis is to understand and improve the mobility performance ofnon-terrestrial and terrestrial networks in a heterogeneous scenario. We first analyze data from system-level simulations of rural deployment scenarios when altering the parameters of the A3 measurement event and and then we further evaluate the use of a new NTN-specific distance-based measurement event, the D1 measurement event. We also evaluate the impact of needing toperform GNSS measurements when performing handovers from a terrestrial to a non-terrestrialnetwork. The results show that acquiring GNSS data during the handover procedure significantly increases handover delay time but does not heavily impact overall network performance. Additionally, the results show that by changing the parameters of the A3 measurement event and using the D1measurement event, ping-pong events between NTN-TN and unnecessary handovers to NTN canbe significantly reduced and improve the overall network performance.

We have witnessed two main trends in recent years that have shaped the current state of communication networks. First, the Internet was designed with the initial idea to provide remote access to resources in the network; today it is overwhelmingly being used for content distribution. In addition, the community of content creators has evolved from a small group of professionals into a global community where every user can generate his contents and share it with other users. Second, the proliferation of personal mobile devices, such as smartphones and media tablets, has altered the way people access, create and share information, leading to a significant migration from wired to wireless networks and raising user expectations for ubiquitous connectivity. These trends have incited research on new communication modes and in this thesis we consider a specific mode, namely opportunistic networking. Opportunistic networking is a communication paradigm that utilizes intermittent connectivity between mobile devices to enable communication in infrastructure-less environments, and to provide complementary transport mechanisms in wireless networks where infrastructure is present. The thesis focuses on two main topics: understanding and modeling human mobility, and opportunistic content distribution. Mobility modeling is one of the key issues in opportunistic networking research. First, we discuss the structure of human mobility and introduce a framework to study mobility at different behavioural levels. We propose a queuing model, denoted by meeting-point model, for pedestrian mobility in smaller urban areas, such as city squares, parks, shops or at bus stops. The model is also a contribution to the second topic we address in the thesis, since we will use it to study characteristics of content distribution in smaller areas. We envision this model as a building block in a library of analytical models that would be used to study the performance of pedestrian content distribution in common scenarios of urban mobility. Furthermore, we show how the proposed model can be used to build larger, more complex models. In the area of opportunistic content distribution, we apply both analytical and simulation-based evaluation. We empirically study the performance of epidemic content distribution by using real-life mobility traces and investigate the fitness of a homogeneous stochastic model to capture the epidemic process. In addition, we present the design, implementation and evaluation of a mobile peer-to-peer system for opportunistic networking and discuss some promising application scenarios. / <p>QC 20131115</p>

Problemformulering: Statskontoret har fått i uppdrag att upphandla ett nytt kommunikationssystem för landets Ambulans, Polis och Räddningstjänsten. Utredningar såsom SOU 1998: 143 har pekat på att TETRA skall väljas. Man kan dock diskutera valet av kommunikationssystem utifrån argumentet att det nya kommunikationssystemet skall skapa mervärde. Detta mervärde kan man tänka endast skapas vid krissituationer. Det är då som fokuset skiftar från kostnader till funktionalitet och de värden man kan spara. Frågan är bara hur ofta kriser och onormala händelser inträffar samt vilka andra påverkbara problem som finns. Sannolikheten att katastrofer inträffar är ofta mycket överdrivna av människan. Även olika typer av trånga sektioner kan begränsa en räddningsinsats. Syfte: Uppsatsens syfte är att undersöka om Ambulans, Polis och Räddningstjänst i Karlskrona/Ronneby kan bedriva sin verksamhet med ett UMTS system för kommunikation, utifrån ett funktionalitets perspektiv, istället för ett TETRA system. Metod: Teknisk jämförelse och en fallstudie hos Ambulans, Polis och Räddningstjänst. Slutsatser: Vi anser att den nyckelskillnad TETRA har, nod till nod, inte har den betydelsen, att UMTS inte skulle kunna ses som ett alternativ till TETRA. UMTS blir även en mer kostnadseffektiv lösning för samhället. / Fredrik Falkenback Folkparksvägen 11:33 372 38 Ronneby Tel: 0457-126 97 Mobil: 070-598 26 97 Emil Numminen Älgbacken 1 372 34 Ronneby Tel: 0457-100 16 Mobil: 070-985 91 19