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In this era of rapid wireless technological advancements, wireless connectivity between humans, humans with machines, and machines with machines is gradually becoming an absolute necessity. The initial motivation for wireless connectivity was to enable voice communication between humans over a geo-graphical area. Thanks to cellular communications advancements in the past decade, cellular wireless connectivity has become a global success, starting from 1G to the present generation 5G. However, the needs of humans often evolve with time, and now the world is witnessing an ever-growing demand for the internet with high data rates besides reliable voice communication. Current cellular networks suffer from non-uniform data rates across a cell, i.e., users at the cell center and the cell edges experience significant variations in signal-to-noise ratio, making the cellular technology less reliable to meet the future data demands. Moreover, cellular networks operating as cells, i.e., an access point (AP, the term we would use instead of base station) serving the users within its geographical location, cannot leverage the network’s total capacity without cooperation among APs of the neighboring cells. One potential solution is moving away from the cell to cell-free networks wherein all the APs will serve all the users within the geographical coverage area. Thus, there is a need for a paradigm shift in how cellular networks operate. Towards the goal mentioned above to fully leverage the network capacity, the Cell-Free Massive multiple-input-multiple-output (MIMO) technology is expected to be the next potential technology beyond 5G combining the benefits of Massive MIMO and cell-free distributed architectures. Distributed architectures require distributed signal processing algorithms, and also energy consumption of the network is crucial. Keeping in view the practical ease in deployment, we consider a sequentially connected Cell-Free Massive MIMO network called a “radio strip, I denna tid av snabba trådlösa tekniska framsteg blir trådlös anslutning mellan människor, mellan människor och maskiner och mellan maskiner och maskiner gradvis en absolut nödvändighet. Den ursprungliga motivationen för trådlös anslutning var att möjliggöra röstkommunikation mellan människor över ett stort geografiskt område. Tack vare framsteg inom mobilkommunikation under det senaste decenniet har mobil trådlös anslutning blivit en global framgång, från 1G till den nuvarande generationen 5G. Men människors behov utvecklats med tiden, och nu bevittnar världen, förutom pålitlig röstkommunikation, en ständigt växande efterfrågan på internet med höga datahastigheter. Nuvarande cellulära nätverk lider av olikformiga datahastigheter över cellen, d.v.s. användare i cellcentret och cellkanterna upplever betydande variationer i signal-brusförhållande, vilket gör den cellulära tekniken mindre lämplig för att möta framtida databehov. Dessutom kan cellulära nätverk som fungerar som celler, d.v.s. att varje accesspunkt (AP, termen vi använder istället för basstation) betjänar användarna inom dess geografiska område, inte utnyttja nätverkets totala kapacitet utan samarbete mellan AP:er i de angränsande cellerna. En potentiell lösning är att gå från cellulära till cellfria nätverk där alla basstationer betjänar alla användare inom det geografiska täckningsområdet. Det finns alltså ett behov av ett paradigmskifte i hur cellulära nätverk fungerar. För att fullt ut utnyttja nätverkskapaciteten, förväntas Cell-Free Massive MIMO vara nästa potentiella teknik bortom 5G som kombinerar fördelarna med Massive MIMO och cellfria distribuerade arkitekturer. Distribuerade arkitekturer kräver distribuerade signalbehandlingsalgoritmer, och även energiförbrukningen i nätverket är av stor vikt. Vi studerar sekventiellt anslutna Cell-Free Massive MIMO-nätverk som kallas “radio stripe”, eftersom dessa är enkla att placera ut. I den första delen av avhandlingen fokuserar vi på att utveckla en opti

RadioWeaves, in which distributed antennas with integrated radio and compute resources serve a large number of users, is envisioned to provide high data rates in next-generation wireless systems. In this paper, we develop a physical layer abstraction model to evaluate the performance of different RadioWeaves deployment scenarios. This model helps speed up system-level simulators of the RadioWeaves and is made up of two blocks. The first block generates a vector of signalto-interference-plus-noise ratios (SINRs) corresponding to each coherence block, and the second block predicts the packet error rate corresponding to the SINRs generated. The vector of SINRs generated depends on different parameters such as the number of users, user locations, antenna configurations, and precoders. We have also considered different antenna gain patterns, such as omni-directional and directional microstrip patch antennas. Our model exploits the benefits of exponential effective SINR mapping (EESM). We study the robustness and accuracy of the EESM for RadioWeaves., Funding Agencies|European Union [101013425]

Cell-free massive multiple-input-multiple-output (mMIMO) is an emerging technology for beyond 5G with its promising features such as higher spectral efficiency and superior spatial diversity as compared to conventional multiple-input-multiple-output (MIMO) technology. The main working principle of cell-free mMIMO is that many distributed access points (APs) cooperate simultaneously to serve all the users within the network without creating cell boundaries. This paper considers the uplink of a cell-free mMIMO system utilizing the radio stripe network architecture with a sequential fronthaul between the APs. A novel uplink sequential processing algorithm is developed, which is proved to be optimal in both the maximum spectral efficiency (SE) and the minimum mean square error (MSE) sense. A detailed quantitative analysis of the fronthaul requirement or signaling of the proposed algorithm and its comparison with competing sub-optimal algorithms is provided. Key conclusions and implications are summarized in the form of corollaries. Based on the analytical and numerical simulation results, we conclude that the proposed scheme can significantly reduce the fronthaul signaling, without compromising the communication performance., Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [2019-05068]; Swedish Research Council (VR)Swedish Research Council [642-2013-7607]; ELLIIT; Knut and Alice Wallenberg (KAW) FoundationKnut & Alice Wallenberg Foundation

Mit einer Bevölkerung von 6,8 Millionen Menschen gehört der Großraum Hyderabad zu den am schnellsten wachsenden städtischen Agglomerationen Südindiens. Das zentrale Thema dieser Dissertation ist die Erforschung der Zusammenhänge zwischen der fortschreitenden Urbanisierung und dem strukturellen Wandel in der peri-urbanen Landwirtschaft im Großraum dieser Megacity Darüber hinaus ist die Erforschung der Sichtweisen und Einstellung der Landwirte zum Thema Nachhaltigkeit für die Arbeit von herausragendem Interesse: z.B., welche Bedeutung hat die Auswahl des Anbausystems auf die Wahl der Anpassungsstrategien? In einer umfassenden Literaturübersicht zum Thema Urbanisierung und peri-urbane Landwirtschaft werden verschiedene Theorien dahingehend analysiert, welche Aussagen sich zu den Auswirkungen der Urbanisierung auf die peri-urbane Landwirtschaft treffen lassen. Wichtige Einflussfaktoren des sich vollziehenden strukturellen Wandels werden herausgearbeitet und die gängigsten Anpassungsmaßnahmen der peri-urbanen Farmer (z.B. zusätzlicher Einsatz von Familienarbeitskräften oder Wechsel in die Nebenerwerbslandwirtschaft), sowie der damit verbundenen Umweltauswirkungen vorgestellt und erklärt. Zudem wird Fragen nachgegangen, wie sich mehr oder weniger nachhaltige Entscheidungen erklären lassen, welche Rolle bei der Umstellung auf nachhaltige Praktiken der Landwirtschaft die Nutzung sozialer Netzwerke wie Familie und Nachbarschaft oder die Mitgliedschaft in bäuerlichen Organisationen spielen. Die Arbeit kommt zu dem Ergebnis, dass infolge der ökologischen Umstellung sich intensivere Kooperationen (collective action) ergaben, die wiederum in Konsequenz sowohl ökologische als auch soziale Nachhaltigkeit förderten. Dies bestätigt die theoretische Annahme, dass wirksame gesellschaftliche Beteiligungen Schlüsselfunktionen für soziale Innovationen darstellen, die zukünftige Politikgestaltung in den Randgebieten von Hyderabad beeinflussen könnten., This thesis explores the ramifications of rapid urbanization on food production in the urban periphery of Greater Hyderabad Area, Southern city of India. In addition this dissertations unpack the wider questions related understanding of sustainability and sustainable farming by the agricultural actors in the urban periphery. The literature review draws attention to the various theories, concepts and pathways of change across the globe. The results particularly focusing on the Indian context indicate that in peri-urban farming along with the increasing cost of production there is associated environmental impacts.To lower these costs, farmers also expanded family labour and resorted to part time farming. In general current developments in the land use of agriculturists indicate an unsustainable use of natural resources where small farms are disappearing and medium size farms are increasing. Also, there is much emphasis on understanding the farmers’ prioritization about the three dimensions of sustainability. Findings reveal that majority of them prioritized the economic criteria rather than environmental and social, where the social sustainability perhaps faded out in the urban peripheries. These results explains the completely different understanding (connotation as well as association) of the term sustainability in this dynamic setting. In the end this dissertation has found that ecological challenge procured community (collective action) and thus prompted environmental sustainability as well as social sustainability confirming the theoretical claim that collective action and effective community participation are core elements of social innovation which might help to shape future politics in Hyderabad’s urban fringes.