Nowadays, Wireless Sensor Networks (WSNs) have gained importance as aflexible, easier deployment/maintenance and cost-effective alternative to wired networks,e.g., Fieldbus and Wired-HART, in a wide-range of applications. Initially,WSNs were mostly designed for military and environmental monitoringapplications where energy efficiency is the main design goal. The nodes in the network were expected to have a long lifetime with minimum maintenance while providing best-effort data delivery which is acceptable in such scenarios. With recent advances in the industrial domain, WSNs have been subsequently extended to support industrial automation applications such as process automation and control scenarios. However, these emerging applications are characterized by stringent requirements regarding reliability and real-time communications that impose challenges in the design of Industrial Wireless Sensor Networks (IWSNs) to effectively support time- and mission-critical applications. Typically, time- and mission-critical applications support different traffic categories ranging from relaxed requirements, such as monitoring traffic to firm requirements, such as critical safety and emergency traffic. The critical traffic is mostly acyclic in nature and occasionally occurs at unpredictable time instants. Once it is generated, it must be delivered within strict deadlines. Exceeding the delay bound could lead to system instability, economic loss, or even endanger human life in the working area. The situation becomes even more challenging when an emergency event triggers multiple sensor nodes to transmit critical traffic to the controller simultaneously. The unpredictability of the arrival of such a type of traffic introduces difficulties with regard to making a suitable scheduling that guarantees data delivery within deadline bounds. Existing industrial standards and related research work have thus far not presented a satisfactory solution to the issue. Therefore, providing deterministic and timely delivery for critical traffic and its prioritization over regular traffic is a vital research topic. Motivated by the aforementioned challenges, this work aims to enable real-timecommunication for time- and mission-critical applications in IWSNs. In this context, improved Medium Access Control (MAC) protocols are proposed to enablea priority-based channel access that provides a timely delivery for acyclic critical traffic. The proposed framework starts with a stochastic modelling of the network delay performance under a priority-oriented transmission scheme, followed by two MAC approaches. The first approach proposes a random Clear Channel Assessment (CCA) mechanism to improve the transmission efficiency of acyclic control traffic that is generated occasionally as a result of observations of an established tendency, such as closed-loop supervisory traffic. A Discrete-Time Markov Chain (DTMC) model is provided to evaluate the performance of the proposed protocol analytically in terms of the expected delay and throughput. Numerical results show that the proposed random CCA mechanism improves the shared slots approach in WirelessHART in terms of delay and throughput along with better transmission reliability. The second approach introduces a slot-stealing MAC protocol based on a dynamic deadline-aware scheduling to provide deterministic channel access in emergency and event-based situations, where multiple sensor nodes are triggered simultaneously to transmit time-critical data to the controller. The proposed protocol is evaluated mathematically to provide the worst-case delay bound for the time-critical traffic and the numerical results show that the proposed approach outperforms TDMA-based WSNs in terms of delay and channel utilization. / SMART (Smarta system och tjänster för ett effektivt och innovativt samhälle)

<p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

<p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

Digital kommunikation är idag självklart för de allra flesta människor, alla kommunicerar digitalt via olika sorters enheter och kanaler. Dock kommer den digitala kommunikationen i väldigt många olika former så kan det ibland bli svårt och komplext för alla att hantera denna sorts kommunikation. Denna studie har för avsikt att skapa ett underlag för en mer komplett och kontrollerbar kommunikation via digitala medel, samt hur ledarskap kan främjas via kommunikation i digital form. Detta ska bidra med en grundläggande kunskap kring hur en organisation bör hantera och förmedla sin information och kommunikation via digitala medel. Studien fokuserar på att skapa en förståelse för hur digital kommunikation upplevs av mottagaren. För att därifrån kunna se hur denna upplevelse kan föras närmare den fysiska kommunikationen mellan en ledare och medarbetare. I ett samarbete med Barn och utbildningsförvaltningen, en väldigt stor organisation med ansvar för all grundutbildning i Eskilstuna kommun, det vill säga allt från förskola upp till gymnasial utbildning. Denna organisation har analyserats genom en induktiv forskningsmetod med kvalitativa intervjuer, dessa har varit grunden för att samla in data. Genom dessa kvalitativa intervjuer samlas åsikter och tankar in från medlemmar av alla olika delar av organisationen för att skapa en heltäckande bild om hur den digitala kommunikationen upplevs och fungerar. Kunskapsbidragets syfte för denna uppsats var att få fram kunskap om hur en digital kommunikationsmiljö bör utformas för att organisationer ska bli mer effektiva, ha ett bra kommunikationsflöde samt mindre informationsbortfall. Detta syfte anses vara uppfyllt genom slutsatserna utifrån teori och empiriinsamling. Där en organisation med en bra struktur, organisationskunskap samt grundtanke har alla möjligheter att då utveckla sina ledare. Detta kan i sin tur utveckla medarbetare och därmed skapa en mer effektiv organisation, med bra och tydliga kanaler där alla är införstådda hur dem fungerar.

Internet of Things (IoT) revolutionise the society of today and tomorrow. IoT redefines technology and innovation, our perception of technology and creates a disruptive market for new products and services. The market of IoT is projected to expand exponentially in coming years, both in terms of a growing customer base and new market actors. However, strict regulations and laws forces new market actors in IoT to develop their management to abiding or comply with regulations and laws, i.e. develop their compliance management. In fast evolving markets as IoT, compliance management is expected to affect the measure of performance for new market actors. Therefore, this thesis address how IoT startups can develop their compliance management practices. To address the purpose of this thesis, a literature review, theoretical framework, interviews and thematic analysis was conducted. The literature review of this thesis identified critical activities at IoT startups for compliance management. The critical activities were business development, product development and customer service. The collection of empirical data through interviews in this thesis addressed how different functions at IoT startups cope with compliance management. The thematic analysis was used to code and cluster the empirical data into overarching themes. The themes addressed how IoT startups could improve their compliance management practices. The identified, underlying mechanisms to improve compliance management practices at IoT startups were improved communication, accountability and risk management. The recommendations from this thesis addressed those underlying mechanisms. The recommendations were: (1) Establish a communication platform, (2) Establish an efficient return process and (3) Risk prioritise compliance standards and activities. Firstly, a communication platform would improve IoT startups’ ability to coordinate and communicate compliance activity information to relevant stakeholders. Secondly, an efficient return process would clarify accountability throughout the value chain, increase customer satisfaction and provide valuable customer insights for product development projects. Thirdly, risk prioritisation of compliance standards and activities would improve resource allocation and reduce costs. The recommendations from this thesis, if implemented, would provide IoT startups with a competitive edge to grow and excel in the market of IoT.

The cellular network operators have witnessed significant growth in data traffic in the past few decades. This growth occurs due to the increases in the number of connected mobile devices, and further, the emerging mobile applications developed for rendering video-based on-demand services. As the frequency bandwidth for cellular communication is limited, significant effort was dedicated to improve the utilization of the available spectrum and increase the system performance via new technologies. For example, 3G and 4G networks were designed to facilitate high data traffic in cellular networks in past decades. Nevertheless, there is a necessity for new cellular network technologies to accommodate the ever-growing data traffic demand. 5G is behind the corner to deal with the tremendous data traffic requirements that will appear in cellular networks in the next decade. Massive MIMO (multiple-input-multi-output) is one of the backbone technologies in 5G networks. Massive MIMO originated from the concept of multi-user MIMO. It consists of base stations (BSs) implemented with a large number of antennas to increase the signal strengths via adaptive beamforming and concurrently serving many users on the same time-frequency blocks. As an outcome of using Massive MIMO technology, there is a notable enhancement of both sum spectral efficiency (SE) and energy efficiency (EE) in comparison with conventional MIMO based cellular networks. Resource allocation is an imperative factor to exploit the specified gains of Massive MIMO. It corresponds to properly allocating resources in the time, frequency, space, and power domains for cellular communication. Power control is one of the resource allocation methods to deliver high spectral and energy efficiency of Massive MIMO networks. Power control refers to a scheme that allocates transmit powers to the data transmitters such that the system maximizes some desirable performance metric. In the first part of this thesis, we investigate reusing the resources of a Massive MIMO system, for direct communication of some specific user pairs known as device-to-device (D2D) underlay communication. D2D underlay can conceivably increase the SE of traditional Massive MIMO systems by enabling more simultaneous transmissions on the same frequencies. Nevertheless, it adds additional mutual interference to the network. Consequently, power control is even more essential in this scenario in comparison with conventional Massive MIMO systems to limit the interference that is caused between the cellular network and the D2D communication, thereby enabling their coexistence. In this part, we propose a novel pilot transmission scheme for D2D users to limit the interference to the channel estimation phase of cellular users in comparison with the case of sharing pilot sequences for cellular and D2D users. We also introduce a novel pilot and data power control scheme for D2D underlaid Massive MIMO systems. This method aims at assuring that D2D communication enhances the SE of the network in comparison with conventional Massive MIMO systems. In the second part of this thesis, we propose a novel power control approach for multi-cell Massive MIMO systems. The new power control approach solves the scalability issue of two well-known power control schemes frequently used in the Massive MIMO literature, which are based on the network-wide max-min and proportional fairness performance metrics. We first explain the scalability issue of these existing approaches. Additionally, we provide mathematical proof for the scalability of our proposed method. Our scheme aims at maximizing the geometric mean of the per-cell max-min SE. To solve this optimization problem, we prove that it can be rewritten in a convex form and then be solved using standard optimization solvers.

To this day, most of the communication networks are characterized by a "monolithic" operating approach. Network elements are configured and operate without any reconfiguration for long time periods. Softwarization, whereby dedicated elements are being replaced by more general-purpose devices, has been lately challenging this existing approach. Virtualizing the infrastructure through the softwarization can provide significant benefits to end users and operators, supporting more flexible service deployment, providing real time monitoring and operational changes.  In Paper I we study a novel allocation technique and traffic optimization process for the access network. Cellular network technologies (i.e. UMTS, LTE, LTE-A) will coexist with non-cellular small cells and offload traffic from cellular to non-cellular networks mainly operating in 3GPP Wi-Fi (IEEE 802.11 standards). This is a scenario for indoor wireless access implementations where offloading mechanisms can improve the QoS offered by the operators, and reduce the traffic handled by the access fronthaul. The analysis of a novel optimization algorithm exhibited a holistic solution for access-core interworking where LWA (LTE-WiFi Aggregation) offers improved performance for the end users.  In order to optimize core network operations factors such as the operational costs should be addressed. Following this approach in Paper II we analysed how environmental factors (e.g. temperature, humidity) can affect the power consumption of core network data centers (cooling systems). By applying machine learning techniques using data from a data center, we were able to forecast the power consumption based on to atmospheric weather conditions and analyse its accuracy.  Optimizing the access network operations and the interworking (resource allocation, scheduling, offloading) can lead to highly configurable and secure operations. These have been factors of great concern as wireless connectivity increases in denser populated areas. In Paper III we examine the physical layer secrecy aspects of a collaborative small cell network in the presence of parallel connections and caching capabilities at the edge nodes. Using tools from the probability theory, we examined how the power allocation for the transmissions can ensure secrecy in the presence of an eavesdropper. / <p>Funding agencies: Europen Union's Horizon 2020 Marie Sk lodowska-Curie Actionsproject WiVi-2020 (H2020-MSCA-ITN-2014-EID 642743-WiVi-2020)</p>

This thesis report investigates how good position estimations that can be done outdoors with received signal strength indication (RSSI) trilateration for sub 1-GHz radio nodes. A custom network and an empirical distance model have been created as well as a technique for weighting multiple distance estimations, using wrapped normal probability density functions. The developed localization system was tested on an open area of one square kilometer, to estimate a node’s position on various locations. To evaluate the localization system, mean and median error of the estimated positions were calculated.

The work is devoted in the development and the exploration of the capabilities of the state of art unlicensed 60GHz (V-Band) mm-wave band that has raised so much interest and attention from numerous companies and laboratories for implementing Multi-gigabit communications [17] and especially for the 5th generation of cellular network and wireless systems. Implementing a high wireless data transfer system requires a high bandwidth and the one around the 60GHz frequency turned out to be a very promising candidate [13]. In this thesis, different protocols were investigated and simulated on MATLAB and implemented on low-cost Field-Programmable Gate Arrays (FPGAs) in order to test its performance with different transmission protocols and systems and insure a robust communication system at the frequency band around 60GHz. Furthermore, the system was tested with a series of different binary sequences such as pseudo-random bi-nary sequences (PRBS-7, PRBS-15, PRBS-23 and PRBS-31) and a high data rate communication link also in the design. The link has been tested in the lab environment and two systems have successfully achieved a relatively low bit-error rate.

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