Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands – Advanced Co-Existence Scenarios

The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co-existences between still used and upcoming mobile networks (from GSM to LTE) and digital terrestrial television broadcasting (DVB) systems. For all of these measurements and their evaluation universal measurement testbed has been proposed and used. Results presented in this paper are a significant part of our activities in work package WP5 in the ENIAC JU project “Agile RF Transceivers and Front-Ends for Future Smart Multi-Standard Communications Applications (ARTEMOS)”

5G Outlook – Innovations and Applications

5G Outlook - Innovations and Applications is a collection of the recent research and development in the area of the Fifth Generation Mobile Technology (5G), the future of wireless communications. Plenty of novel ideas and knowledge of the 5G are presented in this book as well as divers applications from health science to business modeling. The authors of different chapters contributed from various countries and organizations. The chapters have also been presented at the 5th IEEE 5G Summit held in Aalborg on July 1, 2016. The book starts with a comprehensive introduction on 5G and its need and requirement. Then millimeter waves as a promising spectrum to 5G technology is discussed. The book continues with the novel and inspiring ideas for the future wireless communication usage and network. Further, some technical issues in signal processing and network design for 5G are presented. Finally, the book ends up with different applications of 5G in distinct areas. Topics widely covered in this book are: • 5G technology from past to present to the future• Millimeter- waves and their characteristics• Signal processing and network design issues for 5G• Applications, business modeling and several novel ideas for the future of 5

Survey of Spectrum Sharing for Inter-Technology Coexistence

Increasing capacity demands in emerging wireless technologies are expected to be met by network densification and spectrum bands open to multiple technologies. These will, in turn, increase the level of interference and also result in more complex inter-technology interactions, which will need to be managed through spectrum sharing mechanisms. Consequently, novel spectrum sharing mechanisms should be designed to allow spectrum access for multiple technologies, while efficiently utilizing the spectrum resources overall. Importantly, it is not trivial to design such efficient mechanisms, not only due to technical aspects, but also due to regulatory and business model constraints. In this survey we address spectrum sharing mechanisms for wireless inter-technology coexistence by means of a technology circle that incorporates in a unified, system-level view the technical and non-technical aspects. We thus systematically explore the spectrum sharing design space consisting of parameters at different layers. Using this framework, we present a literature review on inter-technology coexistence with a focus on wireless technologies with equal spectrum access rights, i.e. (i) primary/primary, (ii) secondary/secondary, and (iii) technologies operating in a spectrum commons. Moreover, we reflect on our literature review to identify possible spectrum sharing design solutions and performance evaluation approaches useful for future coexistence cases. Finally, we discuss spectrum sharing design challenges and suggest future research directions

Interference mitigation in cognitive femtocell networks

“A thesis submitted to the University of Bedfordshire, in partial fulfilment of the requirements for the degree of Doctor of Philosophy”.Femtocells have been introduced as a solution to poor indoor coverage in cellular communication which has hugely attracted network operators and stakeholders. However, femtocells are designed to co-exist alongside macrocells providing improved spatial frequency reuse and higher spectrum efficiency to name a few. Therefore, when deployed in the two-tier architecture with macrocells, it is necessary to mitigate the inherent co-tier and cross-tier interference. The integration of cognitive radio (CR) in femtocells introduces the ability of femtocells to dynamically adapt to varying network conditions through learning and reasoning. This research work focuses on the exploitation of cognitive radio in femtocells to mitigate the mutual interference caused in the two-tier architecture. The research work presents original contributions in mitigating interference in femtocells by introducing practical approaches which comprises a power control scheme where femtocells adaptively controls its transmit power levels to reduce the interference it causes in a network. This is especially useful since femtocells are user deployed as this seeks to mitigate interference based on their blind placement in an indoor environment. Hybrid interference mitigation schemes which combine power control and resource/scheduling are also implemented. In a joint threshold power based admittance and contention free resource allocation scheme, the mutual interference between a Femtocell Access Point (FAP) and close-by User Equipments (UE) is mitigated based on admittance. Also, a hybrid scheme where FAPs opportunistically use Resource Blocks (RB) of Macrocell User Equipments (MUE) based on its traffic load use is also employed. Simulation analysis present improvements when these schemes are applied with emphasis in Long Term Evolution (LTE) networks especially in terms of Signal to Interference plus Noise Ratio (SINR)

Optimization of Spectrum Management in Massive Array Antenna Systems with MIMO

Fifth generation (5G), is being considered as a revolutionary technology in the telecommunication domain whose the challenges are mainly to achieve signal quality and great ability to work with free spectrum in the millimetre waves. Besides, other important innovations are the introduction of a more current architecture and the use of multiple antennas in transmission and reception. Digital communication using multiple input and multiple output (MIMO) wireless links has recently emerged as one of the most significant technical advances in modern communications. MIMO technology is able to offer a large increase in the capacity of these systems, without requiring a considerable increase in bandwidth or power required for transmission. This dissertation presents an overview of theoretical concepts of MIMO systems. With such a system a spatial diversity gain can be obtained by using space-time codes, which simultaneously exploit the spatial domain and the time domain. SISO, SIMO and MISO systems are differentiated by their channel capacity and their configuration in relation to the number of antennas in the transmitter/receiver. To verify the effectiveness of the MIMO systems a comparison between the capacity of SISO and MIMO systems has been performed using the Shannon’s principles. In the MIMO system some variations in the number of antennas arrays have been considered, and the superiority of transmission gains of the MIMO systems have been demonstrated. Combined with millimetre waves (mmWaves) technology, massive MIMO systems, where the number of antennas in the base station and the number of users are large, is a promising solution. SDR implementations have been performed considering a platform with Matlab code applied to MIMO 2x2 Radio and Universal Software Peripheral Radio (USRP). A detailed study was initially conducted to analyze the architecture of the USRP. Complex structures of MIMO systems can be simplified by using mathematical methods implemented in Matlab for the synchronization of the USRP in the receiver side. SISO transmission and reception techniques have been considered to refine the synchronization (with 16-QAM), thus facilitating the future implementation of the MIMO system. OpenAirInterface has been considered for 4G and 5G implementations of actual mobile radio communication systems. Together with the practical MIMO, this type of solution is the starting point for future hardware building blocks involving massive MIMO systems.A quinta geração (5G) está sendo considerada uma tecnologia revolucionária no setor de telecomunicações, cujos desafios são principalmente a obtenção de qualidade de sinal e grande capacidade de trabalhar com espectro livre nas ondas milimétricas. Além disso, outras inovações importantes são a introdução de uma arquitetura mais atual e o uso de múltiplas antenas em transmissão e recepção. A comunicação digital usando ligaçõe sem fio de múltiplas entradas e múltiplas saídas (MIMO) emergiu recentemente como um dos avanços técnicos mais significativos nas comunicações modernas. A tecnologia MIMO é capaz de oferecer um elevado aumento na capacidade, sem exigir um aumento considerável na largura de banda ou potência transmitida. Esta dissertação apresenta uma visão geral dos conceitos teóricos dos sistemas MIMO. Com esses sistemas, um ganho de diversidade espacial pode ser obtido utilizando códigos espaço-tempo reais. Os sistemas SISO, SIMO e MISO são diferenciados pela capacidade de seus canais e a sua configuração em relação ao número de antenas no emissor/receptor. Para verificar a eficiência dos sistemas MIMO, realizou-se uma comparação entre a capacidade dos sistemas SISO e MIMO utilizado os princípios de Shannon. Nos sistemas MIMO condecideraram-se algumas variações no número de agregados de antenas, e a superioridade dos ganhos de transmissão dos sistemas MIMO foi demonstrada. Combinado com a tecnologia de ondas milimétricas (mmWaves), os sistemas massivos MIMO, onde o número de antenas na estação base e o número de usuários são grandes, são uma solução promissora. As implementações do SDR foram realizadas considerando uma plataforma com código Matlab aplicado aos rádios MIMO 2x2 e Universal Software Peripheral Radio (USRP). Um estudo detalhado foi inicialmente conduzido para analisar a arquitetura da USRP. Estruturas complexas de sistemas MIMO podem ser simplificadas usando métodos matemáticos implementados no Matlab para a sincronização do USRP no lado do receptor. Consideraram-se técnicas de transmissão e recepção SISO para refinar a sincronização (com 16-QAM), facilitando assim a implementação futura do sistema MIMO . Considerou-se o OpenAirInterface para implementações 4G e 5G de sistemas reais de comunicações móveis. Juntamente com o MIMO na pratica, este tipo de solução é o ponto de partida para futuros blocos de construção de hardware envolvendo sistemas MIMO massivos