Insights on Spectrum Sharing in Heterogeneous Networks with Small Cells

This work explores the viability of 5G New Radio spectrum sharing in Ultra High Frequency (UHF), Super High Frequency (SHF) and millimetre wavebands(mmWaves) in outdoor environments. In the mmWaves the linear cellular topology is considered while in the UHF/SHF bands cells with hexagonal shape are assumed. Performance evaluation includes the study of the behaviour of PHY and supported throughput for 2.6, 3.5, 28, 38, 60 and 73 GHz. While the two-slope model is considered for the 2.6 and 3.5 GHz frequency bands, the modified Friis propagation model, with shadow fading, and different values for the standard deviation, is the considered in the millimeter wavebands. With sharing, lower system capacity is supported. We clearly observe that, for coverage distances up to circa 100 m, the supported throughput is higher at the millimetre wavebands, mainly due to the reduction that characterizes the application of the two-slope propagation model at the UHF/SHF bands.Bolsa BID/ICI-FE/Santander Universidades-UBI/2016info:eu-repo/semantics/publishedVersio

Smart Pattern V2I Handover Based on Machine Learning Vehicle Classification

The mmwave frequencies will be widely used in future vehicular communications. At these frequencies, the radio channel becomes much more vulnerable to slight changes in the environment like motions of the device, reflections or blockage. In high mobility vehicular communications the rapidly changing vehicle environments and the large overheads due to frequent beam training are the critical disadvantages in developing these systems at mmwave frequencies. Hence, smart beam management procedures are desired to establish and maintain the radio channels. In this thesis, we propose that using the positions and respective velocities of the vehicles in the dynamic selection of the beam pair, and then adapting to the changing environments using machine learning algorithms, can improve both network performance and communication stability in high mobility vehicular communications

Energy efficiency comparison between 2.1 GHz and 28 GHz based communication networks

Mobile communications have revolutionized the way we communicate around the globe, making communication easier, faster and cheaper. In the first three generations of mobile networks, the primary focus was on voice calls, and as such, the traffic on the networks was not as heavy as it currently is. Towards the fourth generation however, there was an explosive increase in mobile data traffic, driven in part by the heavy use of smart phones, tablets and cloud services, that is in turn increasing heavy energy consumption by the mobile networks to meet increased demand. Addition of power conditioning equipment adds on to the overall energy consumption of the base stations, necessitating deployment of energy efficient solutions to deal with the impacts and costs of heavy energy consumption. This thesis investigates the energy efficiency performance of mobile networks in various scenarios in a dense urban environment. Consideration is given to the future deployment of 5G networks, and simulations are carried out at 2.1 GHz and 28 GHz frequencies with a channel bandwidth of 20 MHz in the 2.1 GHz simulation and 20 MHz in 28 GHz scenario. The channel bandwidth of the 28 GHz system is then increased ten-fold and another system performance evaluation is then done. Parameters used for evaluating the system performance include the received signal strength, signal-to-interference-plus-noise-ratio, spectral efficiency and power efficiency are also considered. The results suggest that deployment of networks using mmWave frequencies with the same parameters as the 2.1 GHz does not improve the overall performance of the system but improves the throughput when a bandwidth of 200 MHz band is allocated. The use of antenna masking with down tilting improves the gains of the system in all three systems. The conclusion drawn is that if all factors are the same, mmWave systems can be installed in the same site locations as 2.1 GHz systems. However, to achieve better performance, some significant modifications would need to be considered, like the use of antenna arrays and beam steering techniques. This simulation has considered outdoor users only, with indoor users eliminated. The parameters in a real network deployment might differ and the results could change, which in turn could change the performance of the system

Beam Alignment for Millimetre Wave Links with Motion Prediction of Autonomous Vehicles

Intelligent Transportation Systems (ITSs) require ultra-low end-to-end delays and multi-gigabit-per-second data transmission. Millimetre Waves (mmWaves) communications can fulfil these requirements. However, the increased mobility of Connected and Autonomous Vehicles (CAVs), requires frequent beamforming - thus introducing increased overhead. In this paper, a new beamforming algorithm is proposed able to achieve overhead-free beamforming training. Leveraging from the CAVs sensory data, broadcast with Dedicated Short Range Communications (DSRC) beacons, the position and the motion of a CAV can be estimated and beamform accordingly. To minimise the position errors, an analysis of the distinct error components was presented. The network performance is further enhanced by adapting the antenna beamwidth with respect to the position error. Our algorithm outperforms the legacy IEEE 802.11ad approach proving it a viable solution for the future ITS applications and services.Comment: Proc. of IET Colloquium on Antennas, Propagation & RF Technology for Transport and Autonomous Platforms, to appea

Millimeter Waves propagation challenges on 5G

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrónica e de TelecomunicaçõesO 5G é conhecido por ser uma tecnologia que pretende agregar conceitos e tecnologias para alavancar a capacidade e cobertura de uma rede móvel. Um dos aspectos mais revolucionários do 5G é a utilização de frequências mais elevadas, para colmatar a pouca largura de banda disponível na banda sub-6 GHz. O 5G fará assim uso de frequências acima dos 6 GHz, nomeadamente entre os 30 e os 300 GHz (ondas milimétricas) que permitem alocar larguras de banda superiores. Esta dissertação apresenta os principais desafios que a banda de ondas milimétricas introduz na propagação. São estudados os diversos mecanismos que provocam atenuação e os modelos de propagação existentes para a quantificação dessas perdas. São apresentados os link budgets para diferentes ambientes que visam avaliar de que forma é que o débito binário é modificado em função das características do canal rádio. Por fim, com base no dimensionamento dos link budgets e na variação do débito binário, foi possível calcular o número de elementos de um agregado de antenas necessário para assegurar esse débito binário. Concluiu-se que para assegurar um débito binário de 2 Gbps, utilizando uma frequência de 28 GHz e uma largura de banda de 0.5 GHz, é necessário um agregado com cerca de 32 elementos. Para atingir 10 Gbps o agregado de antenas teria de ser constituído por cerca de 1.5 milhões de elementos, não sendo uma solução viável. Uma das formas de viabilizar a solução será utilizar 1.5 GHz de largura de banda, traduzindo-se num agregado com cerca de 415 elementos, bem mais realista.The 5G is known for being a technology that aims to agregate concepts and technologies to leverage the capacity and coverage of a mobile network. One of the most revolutionary aspects of 5G is the use of higher frequencies to overcome the few available bandwidth on the sub-6 GHz band. Hence, 5G will be making use of frequencies above the 6 GHz, namely the band between 30 and 300 GHz, the millimeter waves, which allow to allocate larger bandwidths. This dissertation presents the main challenges that millimeter waves induce on propagation. The diverse loss mechanisms are analyzed and the propagation models, that enables the quantification of those losses, are also studied. It is also presented link budgets for different environments, which aim to evaluate the variation of throughput regarding the radio channel characteristics. Finally, the link budgets results and the verified changes on the capacity contribute to calculate the elements number of an antenna array necessary to ensure that capacity. Concluding that to achieve a 2 Gbps capacity, using a 28 GHz frequency and 0.5 GHz of bandwidth, a 32 element array is needed. In order to achieve a capacity of 10 Gbps the array would need to be compound of 1.5 million elements, which is no a viable solution. One way to overcome this constraint is to extend the bandwidth to 1.5 GHz simplifying the antenna into a 415 element array.N/

Towards environmental RF-EMF assessment of mmwave high-node density complex heterogeneous environments

The densification of multiple wireless communication systems that coexist nowadays, as well as the 5G new generation cellular systems advent towards the millimeter wave (mmWave) frequency range, give rise to complex context-aware scenarios with high-node density heterogeneous networks. In this work, a radiofrequency electromagnetic field (RF-EMF) exposure assessment from an empirical and modeling approach for a large, complex indoor setting with high node density and traffic is presented. For that purpose, an intensive and comprehensive in-depth RF-EMF E-field characterization study is provided in a public library study case, considering dense personal mobile communications (5G FR2 @28 GHz) and wireless 802.11ay (@60 GHz) data access services on the mmWave frequency range. By means of an enhanced in-house deterministic 3D ray launching (3D-RL) simulation tool for RF-EMF exposure assessment, different complex heterogenous scenarios of high complexity are assessed in realistic operation conditions, considering different user distributions and densities. The use of directive antennas and MIMO beamforming techniques, as well as all the corresponding features in terms of radio wave propagation, such as the body shielding effect, dispersive material properties of obstacles, the impact of the distribution of scatterers and the associated electromagnetic propagation phenomena, are considered for simulation. Discussion regarding the contribution and impact of the coexistence of multiple heterogeneous networks and services is presented, verifying compliance with the current established international regulation limits with exposure levels far below the aforementioned limits. Finally, the proposed simulation technique is validated with a complete empirical campaign of measurements, showing good agreement. In consequence, the obtained datasets and simulation estimations, along with the proposed RF-EMF simulation tool, could be a reference approach for the design, deployment and exposure assessment of the current and future wireless communication technologies on the mmWave spectrum, where massive high-node density heterogeneous networks are expected.Project RTI2018-095499-B-C31 was funded by the Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (MCIU/AEI/FEDER, UE). This project received funding from Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie Grant 801538

6G Wireless Systems: Vision, Requirements, Challenges, Insights, and Opportunities

Mobile communications have been undergoing a generational change every ten years or so. However, the time difference between the so-called "G's" is also decreasing. While fifth-generation (5G) systems are becoming a commercial reality, there is already significant interest in systems beyond 5G, which we refer to as the sixth-generation (6G) of wireless systems. In contrast to the already published papers on the topic, we take a top-down approach to 6G. We present a holistic discussion of 6G systems beginning with lifestyle and societal changes driving the need for next generation networks. This is followed by a discussion into the technical requirements needed to enable 6G applications, based on which we dissect key challenges, as well as possibilities for practically realizable system solutions across all layers of the Open Systems Interconnection stack. Since many of the 6G applications will need access to an order-of-magnitude more spectrum, utilization of frequencies between 100 GHz and 1 THz becomes of paramount importance. As such, the 6G eco-system will feature a diverse range of frequency bands, ranging from below 6 GHz up to 1 THz. We comprehensively characterize the limitations that must be overcome to realize working systems in these bands; and provide a unique perspective on the physical, as well as higher layer challenges relating to the design of next generation core networks, new modulation and coding methods, novel multiple access techniques, antenna arrays, wave propagation, radio-frequency transceiver design, as well as real-time signal processing. We rigorously discuss the fundamental changes required in the core networks of the future that serves as a major source of latency for time-sensitive applications. While evaluating the strengths and weaknesses of key 6G technologies, we differentiate what may be achievable over the next decade, relative to what is possible.Comment: Accepted for Publication into the Proceedings of the IEEE; 32 pages, 10 figures, 5 table