For mobile IoT devices like mobile collectors gathering data from fixed IoT sensors optimal route planning between two geographical points is essential not only with respect to the length, the traceability, the duration or the economy of the route but especially for bandwidth-demanding applications, the spectrum availability along route. Our scope is the improvement of spectrum exploitation by optimal route selection for moving cognitive IoT devices utilizing TV white space. We investigate the applicability of our proposed new route planning aspects of mobile IoT devices applying cognitive radio technology in TV white space environment. The primary users are in this scenario fixed receivers in the TV UHF band, while the moving secondary users are trying to use the same spectrum in the TV white space without disturbing the primary service and achieve as high data rate as possible. To fulfil the latter condition, an adaptive modulation mode selection algorithm will be also shown. Two different propagation areas, rural and urban have been selected for simulations and calculations.

The Alphasat Scientific Experiment is a satellite propagation experiment representing the continuation of the European Space Agency's (ESA's) commitment to the characterization of the Ka and Q band radio channel. Among several institutions across Europe, Budapest University of Technology and Economics is also taking part in the propagation experiment. The measurement site is located at the university, continuously recording the unmodulated carrier levels of 39.402 GHz and 19.701 GHz along with the main meteorological parameters. The most important phenomenon that causes attenuation is the rain, considering the millimetre wave propagation. Rain intensity is usually measured by different kind of weather sensors, like tipping-bucket, drop-counter type rain gauges or disdrometers. Nevertheless, a point rainfall rate measurement e.g. at the location of the terrestrial endpoint of the radio link usually not correctly represents the rain distribution along the radio path, especially in case of long terrestrial or satellite connections. This paper evaluates the relationship between rain attenuation and rainfall intensity by using the experimental data of Ka/Q band. We extract the rain intensity information by using the measured attenuation on the radio path. For this purpose we process both the Ka and Q-band beacon signals that are transmitted by the Alphasat Aldo Paraboni payload. The dual-frequency approach allows the comparison of the results that may lead to a more accurate attenuation to rain intensity calculation method in the future.

The performance of rain rate and rain attenuation prediction models are vital for planning wireless networks consisting of millimeter wave links. As several different prediction models exist in literature we give a comparison of the performance of the most applied ones. Moreover, we introduce methods for transforming rain attenuation between different millimeter wave links based on the investigated prediction models. This transformation enables the exploitation of long-range link measurements to effectively plan networks comprised of short-range millimeter wave links (like 5G mesh networks). We identify the most suitable rain attenuation prediction model and verify the proposed transformation model with the ITUP. 530-15 model on long-term statistics. The purpose of this paper is to investigate different rain attenuation prediction models for terrestrial links and to find a suitable prediction method to perform a transformation of rain attenuation on millimeter wave links with different physical parameters (length, frequency, and polarization).

Substantial growth of mobile data and rapidly increasing spread of smartphones nowadays present major challenge for mobile service providers. The allotted spectrum for the currently operating mobile communicating systems have been saturated in the last years by such considerable rate that the future's fifth generation network would not be able to fulfil its requirements without applying new frequencies. In accordance with the concept of 5G, millimeter wave spectrum will also be used along with the current frequency bands. This spectrum however, introduces meteorological effects as a new and significant attenuation factor. In this paper millimeter wave propagation affected by precipitation will be investigated and a simulation environment (written in Matlab) used for the 5G mm-wave mesh networks statistical investigation will be presented.

Millimeter wave point to point links have been used as backhaul links for cellular networks for decades. These have always been carefully planned so that their link budgets include a reserve for rain fading. Fast and low cost deployment of 5G backhaul networks may be enabled by a system of millimeter wavelength point to point links where the network is not carefully planned; instead the nodes are semi-randomly deployed and afterwards organized into a network. While this concept has many benefits, rain fading may cause some links to fail, thereby threatening the connectivity of the network. This paper presents the effects of rain fading in such millimeter wavelength mesh networks. The issue is investigated with simulations, and with the use of rain fading measurement data covering a span of five years. Our main result quantifies the probability of network failure due to rain fading in millimeter wave flexible backhaul mesh networks of future 5G systems.

As rainfall has a serious effect on wireless microwave transmission, performance of rain rate and rain attenuation prediction models are vital for planning of networks consisting of such links. As several different prediction models exist in the literature we give a comparison of the performance of the most applied ones. Moreover, we introduce the transformation of rain attenuation over different microwave links based on the investigated methods. We identify the most suitable rain attenuation prediction model and verify the proposed link transformation model with the ITU-P.530-15 model on long-term statistics. The purpose of this document is to investigate different rain attenuation prediction models for terrestrial links and to find a suitable prediction method to perform a transformation of rain attenuation on microwave links with different physical parameters.

Substantial growth of mobile data and rapidly increasing spread of smartphones nowadays present major challenge for mobile service providers. The allotted spectrum for the currently operating mobile communicating systems have been saturated in the last years by such considerable rate that the future's fifth generation network would not be able to fulfil its requirements without applying new frequencies. In accordance with the concept of 5G, millimeter wave spectrum will also be used along with the current frequency bands.This spectrum however, introduces meteorological effects as a new and significant attenuation factor. In this paper mm-wave propagation affected by precipitation will be investigated and a simulation environment (written in Matlab) used for the 5G mm-wave mesh networks statistical investigation will be presented.

Since wireless service providers have to overcome a global bandwidth shortage, one of the main concepts of future 5th generation wireless systems is the application of the millimeter wave bands that offers a larger channel bandwidth than actual wireless networks. However, propagation of the wireless signal in the millimeter wave spectrum is different from the spectrum of the currently applied 2G, 3G and 4G networks. For microwave telecommunications links that are operating above 10 GHz one of the most harmful circumstantial factors is the attenuation caused by precipitation, especially by rain. Recent studies indicate that future cellular 5G networks will apply a cell-radius of 200 meters. Detailed analysis of the effects of path loss caused by multipath delay spread can be found in relevant literature, however effects of rain attenuation on these short links is less studied. Moreover, a non-constant climate indicates special considerations for the planning of 5G networks, therefore attenuation caused by precipitation needs to be investigated. In this paper effects of the varying climate and varying precipitation distribution on the performance of millimeter wave 5G networks is investigated on the basis of the data provided by a millimeter wave measurement system that is operating at our premises.

This paper investigates filter bankmulticarrier (FBMC), a multicarrier modulation technique exhibiting an extremely low adjacent channel leakage ratio (ACLR) compared to conventional orthogonal frequency division multiplexing (OFDM) technique. The low ACLR of the transmitted FBMC signal makes it especially favorable in cognitive radio applications, where strict requirements are posed on out-of-band radiation. Large dynamic range resulting in high peak-to-average power ratio (PAPR) is characteristic of all sorts of multicarrier signals. The advantageous spectral properties of the high-PAPR FBMC signal are significantly degraded if nonlinearities are present in the transceiver chain. Spectral regrowth may appear, causing harmful interference in the neighboring frequency bands. This paper presents novel clipping based PAPR reduction techniques, evaluated and compared by simulations and measurements, with an emphasis on spectral aspects. The paper gives an overall comparison of PAPR reduction techniques, focusing on the reduction of the dynamic range of FBMC signals without increasing out-of-band radiation. An overview is presented on transmitter oriented techniques employing baseband clipping, which can maintain the system performance with a desired bit error rate (BER).

Microwave telecommunications links that are operating above 10 GHz are significantly affected by precipitation, especially by rain. In order to study the attenuation caused by precipitation a measurement system is operating at BME-HVT. The results of the measurement system can also help to examine the change of the climate, whereas variations in the intensity and frequency of precipitation indicate variations in the characteristics of the propagation of microwaves as well. A nonconstant climate indicates necessary changes in the network planning of microwave telecommunication networks in order to adapt the link performance (i.e. availability, fade margin, etc.) to the forthcoming climate conditions. Moreover, whereas the climate can vary in time and space as well, it is important to have the local trends of the variation available. Our objective is to study the effects of the climate variability and climate change on the availability of the microwave networks by processing the attenuation measurement data of microwave links recorded during the last 14 years within local (Hungarian) conditions. In this paper results of four microwave links established in Budapest are investigated. In order to get a joint statistics of diverse links a transformation was performed on the attenuation data measured on the investigated microwave links. Thereby a local trend in the attenuation and fade duration statistics became available to be investigated, which is specific to Budapest. The results can help to improve the recommendations on microwave network planning and adapt them to the varying climate.

For microwave telecommunications links that are operating above 10 GHz one of the most harmful circumstantial factors is the attenuation caused by precipitation, especially by rain. In order to investigate this phenomenon a measurement system is operating at Budapest University of Technology and Economics, Department of Broadband Infocommunicatons and Electromagnetic Theory (BME-HVT), which system measures the received signal level values on microwave links established in many locations in Hungary. Furthermore, the results of the measurement system help to examine the change of the climate as well. Our aim is to study the effects of the climate change by processing the attenuation measurement data on microwave links recorded during the last 14 years. In this paper the changes occurred in the duration and frequency of the fade events were investigated.

A major challenge for cooperative cognitive radio networks is the creation and optimisation of a suitable spectrum portfolio, utilised by the radio nodes in the process of dynamic spectrum management. This paper presents several optimisation approaches for spectrum portfolios. Their characteristics are discussed regarding a variety of different scenarios, and it is shown how different approaches can complement each other to optimise the overall spectrum management, in particular considering spectrum portfolio optimisation under mobility and QoS constraints. Special consideration of upcoming TV whitespace communication use cases is shown in this discussion.

Free-space optical (FSO) and microwave telecommunication links have considerably adverse propagation characteristics. For radio waves that are operating in the millimeter wavelength one of the most harmful circumstantial factors is the attenuation caused by precipitation, especially by rain. However, for FSO links the main adverse effect is fog, being most responsible for the unavailability of FSO links. These adverse propagation characteristics allow good efficiency for a site diversity system that consists of parallel FSO and millimeterwave links. In order to study the propagation characteristics of these types of links a measurement system is operating at Budapest University of Technology and Economics, Department of Broadband Infocommunicatons and Electromagnetic Theory (BME-HVT). In this paper the efficiency of a parallel FSO-microwave site diversity system is presented on the basis of the results of the measurement system. The outage probabilities of the FSO and microwave links are compared to the outage probability of the diversity system. Moreover, the possibility of microwave transmitter power reduction is investigated as well in case of the application of the hybrid diversity system.

The atmospheric turbulence is one of the cause of channel impairments of the free space optical links. This phenomenon appears even in case of clear sky conditions and according to the literature it may affect the availability of the connection. In this paper the atmospheric turbulence will be studied, based on longterm measurement data. The measurements were performed on a 930m long free space optical link that operates at 785 nm wavelength.

This report presents a consolidated view of the QoSMOS system architecture. Details are given for the technical solutions developed within the project, which cover the various roles within the system architecture. These solutions are evaluated using selected performance metrics. The technical tools Quality Of Service and MObility driven cognitive radio Systems

In order to increase the user Quality of Experience (QoE), transport functions could exploit the presence of multiple communication channels. Combining multilink architecture developed by the CELTIC MARCH project and adaptive video transmission can be an effective solution for transmitting video streams. Our multilink gateway method aims to increase the quality of the video transmission by splitting and merging the video stream in accord with the importance of the different parts of the video stream into multiple access networks ranked adaptively to the network performance. Our method guarantees the transmission of the highest priority MPEG-2 frames trough the best network available instantaneously.