Wide-band channel sounding in the bands above 2GHz

Modem telecommunication services require increasing data rates for both mobile and fixed applications. At frequencies in the range 2.5 GHz to 6 GHz physical constraints on the size of equipment result in antenna with moderate directivity typically with an antenna beam width of 20 degrees or greater. Thus building and ground clutter is present within the first Fresnel zones of the antenna system which gives rise to multi-path propagation. This multi-path propagation (average delay and RMS delay spread) has been investigated using a wideband FMCW channel sounder that is capable of operation at a number of frequencies. The channel sounder has been based upon a parallel architecture sounder operating within the 2 GHz band with a number of frequency conversion modules to translate operation to the new frequency bands under study. Two primary configurations have been explored. In the first of these, propagation has been measured simultaneously within the 2.5 GHz, 3.4 GHz and 5.7 GHz bands. This is believed to be novel and original. In the second configuration four parallel channels operating within the 5.7 GHz band may be operated simultaneously. This configuration supports multiple antennas at the receiver. To support the work in the bands from 2.5 GHz to 6 GHz wideband discone antenna have been designed and fabricated. A system to provide relative gain and phase calibration for up to four antennas has been developed and demonstrated. This is also believed to represent a novel method of performing antenna and array calibration. Finally, the frequency converters have been used in conjunction with additional components to provide an FMCพ sounder operating within the 60 GHz Oxygen absorption band. This work is novel in that up to 1 GHz of spectrum can be swept. To support this work a significant number of microwave components have been designed and developed. In particular a novel wide band balanced X3 multiplier and a novel impedance-matched amplitude-equaliser (to provide amplifier gain-slope equalisation) has been developed. Channel soundings have been performed at three frequencies simultaneously using band specific and common antenna. The average delay and RMS delay spread have been demonstrated to be essentially frequency independent for the environments evaluated

Characterisation of MIMO radio propagation channels

Due to the incessant requirement for higher performance radio systems, wireless designers have been constantly seeking ways to improve spectrum efficiency, link reliability, service quality, and radio network coverage. During the past few years, space-time technology which employs multiple antennas along with suitable signalling schemes and receiver architectures has been seen as a powerful tool for the implementation of the aforementioned requirements. In particular, the concept of communications via Multiple-Input Multiple-Output (MIMO) links has emerged as one of the major contending ideas for next generation ad-hoc and cellular systems. This is inherently due to the capacities expected when multiple antennas are employed at both ends of the radio link. Such a mobile radio propagation channel constitutes a MIMO system. Multiple antenna technologies and in particular MIMO signalling are envisaged for a number of standards such as the next generation of Wireless Local Area Network (WLAN) technology known as 802.1 ln and the development of the Worldwide Interoperability for Microwave Access (WiMAX) project, such as the 802.16e. For the efficient design, performance evaluation and deployment of such multiple antenna (space-time) systems, it becomes increasingly important to understand the characteristics of the spatial radio channel. This criterion has led to the development of new sounding systems, which can measure both spatial and temporal channel information. In this thesis, a novel semi-sequential wideband MIMO sounder is presented, which is suitable for high-resolution radio channel measurements. The sounder produces a frequency modulated continuous wave (FMCW) or chirp signal with variable bandwidth, centre frequency and waveform repetition rate. It has programmable bandwidth up to 300 MHz and waveform repetition rates up to 300 Hz, and could be used to measure conventional high- resolution delay/Doppler information as well as spatial channel information such as Direction of Arrival (DOA) and Direction of Departure (DOD). Notably the knowledge of the angular information at the link ends could be used to properly design and develop systems such as smart antennas. This thesis examines the theory of multiple antenna propagation channels, the sounding architecture required for the measurement of such spatial channel information and the signal processing which is used to quantify and analyse such measurement data. Over 700 measurement files were collected corresponding to over 175,000 impulse responses with different sounder and antenna array configurations. These included measurements in the Universal Mobile Telecommunication Systems Frequency Division Duplex (UMTS-FDD) uplink band, the 2.25 GHz and 5.8 GHz bands allocated for studio broadcast MIMO video links, and the 2.4 GHz and 5.8 GHz ISM bands allocated for Wireless Local Area Network (WLAN) activity as well as for a wide range of future systems defined in the WiMAX project. The measurements were collected predominantly for indoor and some outdoor multiple antenna channels using sounding signals with 60 MHz, 96 MHz and 240 MHz bandwidth. A wide range of different MIMO antenna array configurations are examined in this thesis with varying space, time and frequency resolutions. Measurements can be generally subdivided into three main categories, namely measurements at different locations in the environment (static), measurements while moving at regular intervals step by step (spatial), and measurements while the receiver (or transmitter) is on the move (dynamic). High-scattering as well as time-varying MIMO channels are examined for different antenna array structures

Radio frequency channel characterization for energy harvesting in factory environments

This thesis presents ambient energy data obtained from a measurement campaign carried out at an automobile plant. At the automobile plant, ambient light, ambient temperature and ambient radio frequency were measured during the day time over two days. The measurement results showed that ambient light generated the highest DC power. For plant and operation managers at the automobile plant, the measurement data can be used in system design considerations for future energy harvesting wireless sensor nodes at the plant. In addition, wideband measurements obtained from a machine workshop are presented in this thesis. The power delay profile of the wireless channel was obtained by using a frequency domain channel sounding technique. The measurements were compared with an equivalent ray tracing model in order to validate the suitability of the commercial propagation software used in this work. Furthermore, a novel technique for mathematically recreating the time dispersion created by factory inventory in a radio frequency channel is discussed. As a wireless receiver design parameter, delay spread characterizes the amplitude and phase response of the radio channel. In wireless sensor devices, this becomes paramount, as it determines the complexity of the receiver. In reality, it is sometimes difficult to obtain full detail floor plans of factories for deterministic modelling or carry out spot measurements during building construction. As a result, radio provision may be suboptimal. The method presented in this thesis is based on 3-D fractal geometry. By employing the fractal overlaying algorithm presented, metallic objects can be placed on a floor plan so as to obtain similar radio frequency channel effects. The environment created using the fractal approach was used to estimate the amount of energy a harvesting device can accumulate in a University machine workshop space

Wideband mobile propagation channels: Modelling measurements and characterisation for microcellular environments

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Doctor of Philosophy

dissertationThe wireless radio channel is typically thought of as a means to move information from transmitter to receiver, but the radio channel can also be used to detect changes in the environment of the radio link. This dissertation is focused on the measurements we can make at the physical layer of wireless networks, and how we can use those measurements to obtain information about the locations of transceivers and people. The first contribution of this work is the development and testing of an open source, 802.11b sounder and receiver, which is capable of decoding packets and using them to estimate the channel impulse response (CIR) of a radio link at a fraction of the cost of traditional channel sounders. This receiver improves on previous implementations by performing optimized matched filtering on the field-programmable gate array (FPGA) of the Universal Software Radio Peripheral (USRP), allowing it to operate at full bandwidth. The second contribution of this work is an extensive experimental evaluation of a technology called location distinction, i.e., the ability to identify changes in radio transceiver position, via CIR measurements. Previous location distinction work has focused on single-input single-output (SISO) radio links. We extend this work to the context of multiple-input multiple-output (MIMO) radio links, and study system design trade-offs which affect the performance of MIMO location distinction. The third contribution of this work introduces the "exploiting radio windows" (ERW) attack, in which an attacker outside of a building surreptitiously uses the transmissions of an otherwise secure wireless network inside of the building to infer location information about people inside the building. This is possible because of the relative transparency of external walls to radio transmissions. The final contribution of this dissertation is a feasibility study for building a rapidly deployable radio tomographic (RTI) imaging system for special operations forces (SOF). We show that it is possible to obtain valuable tracking information using as few as 10 radios over a single floor of a typical suburban home, even without precise radio location measurements

5G network planning and optimisation using Atoll

This thesis consists on the study of some 5G NR key features such as massive MIMO and beamforming and how they are modelled by Atoll, a network design and planning software. For this, a single cell was deployed on a sample area of Barcelona and different coverage, signal quality, capacity predictions and simulations were carried out. Some parameters such as the receiver height, the transmitter height, the number of antennas used in transmission and reception, the number of beams used by the beam-based antennas, the number of users and the different MIMO techniques, were tested and varied in order to understand their impact in area the cell can cover, its capacity, the traffic loads that can be handled and the data rates experienced by the users. From the different studies performed, it was demonstrated how beamforming improved the signal quality and the network capacity thanks the high gain beams pointed toward users. Also, it was shown how the different MIMO techniques made use of diversity and capacity gains to improve the C/(I+N) level at the receiver and the user throughput.Esta tesis consiste en el estudio de algunas de las características principales de 5G NR como lo son massive MIMO y beamforming y cómo son modeladas por Atoll, un software de diseño y planificación de redes. Para ello, una sola celda fue desplegada en un área de muestra de Barcelona y diferentes predicciones de cobertura, calidad de señal, capacidad y simulaciones fueron llevadas a cabo. Algunos parámetros, como la altura del receptor, la altura del transmisor, el número de antenas usado en transmisión y recepción, el número de beams utilizado por las antenas con capacidades de beamforming, el número de usuarios y las diferentes técnicas de MIMO fueron probadas y variadas con el fin de entender su impacto en el área que una celda puede cubrir, su capacidad, las cargas de tráfico que pueden ser manejadas y la velocidad de datos experimentada por los usuarios. De los diferentes estudios realizados, pudo ser demostrado cómo beamforming mejoró la calidad de la señal y la capacidad de la red gracias a los beams con alta ganancia apuntados hacia los diferentes usuarios. También, fue mostrado cómo las diferentes técnicas de MIMO hicieron uso de las ganancias de diversidad y de capacidad para mejorar el nivel de C/(I+N) en el receptor y las velocidades en el usuario.Aquesta tesi consisteix en l'estudi d'algunes de les característiques principals de 5G NR com són massive MIMO i beamforming i com són modelades per Atoll, un programari de disseny i planificació de xarxes. Per a això, va ser desplegada una sola cel·la en una àrea de mostra de Barcelona i van ser dutes a terme diferents prediccions de cobertura, qualitat de senyal, capacitat i simulacions. Alguns paràmetres van ser provades i variats com l'altura del receptor, l'altura del transmissor, el nombre d'antenes usat en transmissió i recepció, el nombre de beams utilitzat per les antenes amb capacitats de beamforming, el nombre d'usuaris i les diferents tècniques de MIMO, per tal d'entendre el seu impacte en l'àrea que una cel·la pot cobrir, la seva capacitat, les càrregues de trànsit que poden ser manejades i velocitats de dades experimentada pels usuaris. Dels diferents estudis realitzats, va poder ser demostrat com el beamforming va millorar la qualitat del senyal i la capacitat de la xarxa gràcies als beams amb alt guany apuntant cap als diferents usuaris. També, va ser mostrat com les diferents tècniques de MIMO van fer ús dels guanys de diversitat i de capacitat per millorar el nivell de C/(I+N) en el receptor i les velocitats en l'usuari

The development of the terrestrial broadcasting networks of the United Kingdom in the twentieth century

This thesis describes an investigation into the evolution of terrestrial broadcasting -a vital new medium that has had an enormous social impact. The approach has been to concentrate upon the research and development needed to plan the intricate radio and television transmitter networks. These processes required national and international agreement on the use of the radio frequency spectrum, and the specification of many hundreds of transmitting stations. They provided the link between the broadcasters and the public, and this work presents a unique illustration of a project which dealt with many novel technical problems whilst accommodating the demands of all those concerned with the exploitation of the medium. The UK became prominent in the field of broadcasting technology, particularly in areas concerned with propagation and service planning. The geographical position of this country between large land and sea masses, the nature of its terrain, meteorology and its population distribution, presented a wide range of distinctive problems. Research in the UK provided valuable evidence for the subsequent planning of services throughout the world, although during the rapid development of broadcasting it was impossible to examine fully all the experimental results which were produced. With resources not previously available, the author - engaged on planning work since the middle of the century - has researched evidence much of which was archived many years ago. It is not simply a work of historical interest, because new information concerning radio propagation has emerged. Its timing is also appropriate, because the beginning of the twenty-first century is witnessing revolutionary changes in broadcasting

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion