Investigation of Techniques for Reducing Mobile Communication Systems Harmful Out-Of-Band Emission

Electromagnetic compatibility in the newly designated Long-Term Evolution (LTE) mobile network in the 790–862 MHz frequency band from perspective of interference management between neighbouring services are analysed in the dissertation. Main focal point of this dissertation is on the problems that face LTE networks based on Orthogonal Frequency-Division Multiplexing (OFDM) due to the relatively strong side lobes around the active subcarriers in the main communication channel, which introduces interference effects between LTE stations and other services. The introductory chapter presents the investigated problem, objects of research, importance of the dissertation, describes research methodology, scientific novelty and the defended statements. The situation in the 790–862 MHz frequency band is overviewed regarding most sensitive challenges in the first chapter: LTE stations’ influence on Short-Range Devices (SRD), digital terrestrial TV broadcasting (DVB-T) and aeronautical radio navigation systems (ARNS). The noticeable lack of information is observed regarding SRD and LTE electromagnetic compatibility. The Filter Bank Multicarrier Transmission technique (FBMC) is pro-posed as means to minimize adjacent band interference in the 790–862 MHz frequency band. Main FBMC benefits are presented through comparison with reference case of OFDM. The key advantage of FBMC technique is derived from its low out-of-band leakage, which guarantees minimum harmful interference level between stations using adjacent channels. The harmful interference of LTE mobile stations’ influence on Short-Range Devices operating in the 863–870 MHz frequency band is analysed in the second chapter. Two analysis methods are used in this study: first applying theoretical analysis using Minimum Coupling Loss calculations, then statistical Monte-Carlo in order to verify results obtained in theoretical approach. The third chapter is focused on the experimental analysis to reproduce the situation that was investigated in theoretical analysis chapter. Verification of theoretical analysis by practical measurements confirmed that the LTE user equipment (UE) emissions may affect SRD devices and completely or partially disrupt their communications at distances of up to several meters from LTE UE. The obtained results are summarized and general conclusions are drawn

Broadband Spectrum Survey Measurements for Cognitive Radio Applications

It is well known that the existing spectrum licensing system results in a gross under-utilization of the frequency spectrum. Spectrum background measurements – spectrum surveys – provide useful data for spectrum regulation, planning or finding frequency niches for spectrum sharing. Dynamic spectrum sharing as a main goal of cognitive radio (CR) is the modern option on how to optimize usage of the frequency spectrum. A spectrum survey measurement system is introduced with results obtained from a variety of markedly different scenarios allowing us, unlike other studies, to focus on wideband and fast spectrum scans. The sensitivity of the receiver is no worse than -113 dBm in the whole band. The utilization of the frequency spectrum is analyzed to prove its under-utilization and to show spectrum sharing opportunities. This was shown to be true in the frequency band higher than 2.5 GHz. A comparison with other spectrum survey campaigns is provided

When is electromagnetic spectrum fungible?

Fungibility is a common assumption for market-based spectrum management. In this paper, we explore the dimensions of practical fungibility of frequency bands from the point of view of the spectrum buyer who intends to use it. The exploration shows that fungibility is a complex, multidimensional concept that cannot casually be assumed. We develop two ideas for quantifying fungibility-(i) of a fungibility space in which the 'distance' between two slices of spectrum provides score of fungibility and (ii) a probabilistic score of fungibility. © 2012 IEEE

Uncoordinated access schemes for the IoT: approaches, regulations, and performance

Internet of Things (IoT) devices communicate using a variety of protocols, differing in many aspects, with the channel access method being one of the most important. Most of the transmission technologies explicitly designed for IoT and Machine-to-Machine (M2M) communication use either an ALOHA-based channel access or some type of Listen Before Talk (LBT) strategy, based on carrier sensing. In this paper, we provide a comparative overview of the uncoordinated channel access methods for IoT technologies, namely ALOHA-based and LBT schemes, in relation with the ETSI and FCC regulatory frameworks. Furthermore, we provide a performance comparison of these access schemes, both in terms of successful transmissions and energy efficiency, in a typical IoT deployment. Results show that LBT is effective in reducing inter-node interference even for long-range transmissions, though the energy efficiency can be lower than that provided by ALOHA methods. The adoption of rate-adaptation schemes, furthermore, lowers the energy consumption while improving the fairness among nodes at different distances from the receiver. Coexistence issues are also investigated, showing that in massive deployments LBT is severely affected by the presence of ALOHA devices in the same area

State-of-the-art in Power Line Communications: from the Applications to the Medium

In recent decades, power line communication has attracted considerable attention from the research community and industry, as well as from regulatory and standardization bodies. In this article we provide an overview of both narrowband and broadband systems, covering potential applications, regulatory and standardization efforts and recent research advancements in channel characterization, physical layer performance, medium access and higher layer specifications and evaluations. We also identify areas of current and further study that will enable the continued success of power line communication technology.Comment: 19 pages, 12 figures. Accepted for publication, IEEE Journal on Selected Areas in Communications. Special Issue on Power Line Communications and its Integration with the Networking Ecosystem. 201

Energy efficient CM2M communications in E-healthcare systems

In this paper, cognitive machine to machine (CM2M) gateways in e-healthcare systems are presented by accessing a number of channels via periodic sensing and spectrum handoff. An optimal energy efficient spectrum management mechanism with multiple thresholds is proposed. The developed mechanism aims to reduce energy consumption in the system by optimizing the spectrum sensing and the channel switching, while decreasing the probability of collision, with assuring the reliability thresholds, throughput, and delay. Subsequently an antenna selection sensing (ASS) scheme is used to improve sensing accuracy. The simulation results show that the energy efficiency of the CM2M gateways can be improved significantly

System for Detection of Malicious Wireless Device Patterns

The research within presents the use of Hidden Markov Models (HMM) for the detection of wireless devices in highly noisy environments using their unintended electromagnetic emissions (UEE). All electromagnetic devices emit such radiation that is unique to the electronics, housing, and other device attributes. This pattern recognition system can provide continuous detection analysis and can provide ideal information regarding the distance to an unknown device. An experiment was performed where UEE of a device was detected by a spectrum analyzer. Experimental result shows that our model can accurately detect if there is a device nearby emitting UEE or not

Interfered technology: A radiant future: A look forward to EMC in 2023, five years from now

In 1973, a three-part full-page article was published in the local newspaper describing our society in the region of Twente, the Netherlands, in 1923, 1973, and 2023 [1]. The author of this article was only 11 years old at the time, but the predictions made were interesting enough to keep that article for 45 years. The article [1] predicted several innovations for 2023, 50 years ahead, such as a magnetic levitation monorail from Twente to Amsterdam reducing the travel time from 2 hours to less than 30 minutes, as shown in Figure 1. However, all we got after 45 years was a new motorway, with lots of traffic jams, and a train that still takes 2 hours. Despite over a century of research and development, maglev trains are currently operated in just three countries: Japan, South Korea, and China. Other innovations predicted in 1973 for 2023 were clothes made by printers (yes, nearly), no cars in city centres (yes), products made in Shanghai (yes), European regions instead of European countries (no, although Catalonia would like this), no manufacturing but only research and development (no), Holec and Signaal merged (no, Holec split up into several divisions now owned by Siemens, Eaton, and General Electric, and Signaal was sold by Philips to Thomson-CSF, now THALES). And the announcement that the University of Twente will be organizing a conference on communication technology, including electronics. This was a very good prediction: communication technology will be a key issue in 2023