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Yes / A modified indoor path loss prediction model is presented, namely Effective Wall Loss Model (EWLM). The modified model is compared to other indoor path loss prediction models using simulation data and real-time measurements. Different operating frequencies and antenna polarizations are considered to verify the observations. In the simulation part, EWLM shows the best performance among other models as it outperforms two times the dual slope model which is the second-best performance. Similar observations were recorded from the experimental results. Linear attenuation and one slope models have similar behaviour, the two models parameters show dependency on operating frequency and antenna polarization.

This thesis examines methods to enhance the realism of signal strength simulations in a Radio Access Network (RAN) test environment by identifying and analyzing factors that influence signal strength in actual RAN settings. The study addresses different attenuation impacts using three technical reports: 3GPP TR 38.901 for path loss in various area scenarios, ITU-R P.838 for rain attenuation, and ITU-R P.840 for cloud and fog attenuation effects. This thesis also considers inter-cell interference as a proof of concept to understand its impact on signal quality. Key findings indicate that path loss substantially affects signal strength, significantly influenced by frequency, distance between transmitter and receiver, and the environmental context (e.g., rural or urban). Although rain and cloud attenuation also affect signal strength, their impact is minor but increases with higher frequencies. This thesis enriches our understanding of more accurately simulating signal strength in RAN environments by focusing on path loss, rain, cloud attenuation, and inter-cell interference. This work lays a foundation for subsequent studies to expand upon, particularly in integrating diverse attenuation factors, thereby driving forward the precision and reliability of future RAN simulations.

Implanted Devices are important components of the Wireless Body Area Network (WBAN) as a promising technology in biotelemetry, e-health care and hyperthermia applications. The design of WBAN faces many challenges, such as frequency band selection, channel modeling, antenna design, physical layer (PHY) protocol design, medium access control (MAC) protocol design and power source. This research focuses on the design of implanted antennas, channel modeling between implanted devices and Wireless Power Transfer (WPT) for implanted devices. An implanted antenna needs to be small while it maintains Specific Absorption Rate (SAR) and is able to cope with the detuning effect due to the electrical properties of human body tissues. Most of the proposed antennas for implanted applications are electric field antennas, which have a high near-zone electric field and, therefore, a high SAR and are sensitive to the detuning effect. This work is devoted to designing a miniaturized magnetic field antenna to overcome the above limitations. The proposed Electrically Coupled Loop Antenna (ECLA) has a low electric field in the near-zone and, therefore, has a small SAR and is less sensitive to the detuning effect. The performance of ECLA, channel model between implanted devices using Path Loss (PL) and WPT for implanted devices are studied inside different human body models using simulation software and validated using experimental work. The study is done at different frequency bands: Medical Implanted Communication Services (MICS) band, Industrial Scientific and Medical (ISM) band and 3.5 GHz band using ECLA. It was found that the proposed ECLA has a better performance compared to the previous designs of implanted antennas. Based on our study, the MICS band has the best propagation channel inside the human body model among the allowed frequency bands. The maximum PL inside the human body between an implanted antenna and a base station on the surface is about 90 dB. WPT for implanted devices has been investigated as well, and it has been shown that for a device located at 2 cm inside the human body with an antenna radius of 1 cm an efficiency of 63% can be achieved using the proposed ECLA. / Ph. D.

In the push for spectrum sharing and open spectrum access, the 3.5 GHz frequency band is under consideration for small cells and general Wireless Local Area Networks (WLAN) in the United States. The same band is beginning to see deployment in China, Japan, and South Korea, for the 4G Long Term Evolution (LTE) cellular standard to increase coverage and capacity in urban areas through small cell deployment. However, since the adoption of this band is new, there is a distinct shortage of propagation data and accurate channel modeling at 3.5 GHz in indoor environments. These models are necessary for cellular coverage planning and evaluating the performance and feasibility of wireless systems. This report presents the results of a fixed wireless channel measurement campaign at 3.5 GHz. Measurements were taken in environments typical of indoor wireless deployment: traditional urban indoor office, hallway, classroom, computer laboratory, and atrium areas, as well as within a hospital. Primarily Non Line of Sight (NLOS) experiments were carried out in areas with a controllable amount of partitions separating the transmitter and receiver in order to document material-based attenuation values. Indoor-to-outdoor measurements were carried out, focusing on attenuation due to common exterior building materials such as concrete, brick, wood, and reinforced glass. Documented metrics include large scale path loss, log-normal shadowing, and channel power delay profiles combined with delay spread characteristics for multipath analysis. The statistical multi-antenna diversity gain was evaluated to gauge the benefit of using multi-antenna systems in an indoor environment, which has much greater spatial diversity than an outdoor environment. Measurements were compared to indoor path loss models used for WLAN planning in the low GHz range to investigate the applicability of extending these models to 3.5 GHz. / Master of Science

Ultra-wideband (UWB) communication is emerging as a new wireless technology, which promises high data rates with low interference and low power consumption. The development of such UWB systems requires a sufficiently large amount of data to characterize the propagation behavior of UWB signals in indoor environments and develop accurate channel models. This thesis focuses primarily on a frequency-domain approach for propagation measurements and characterization of indoor UWB channels. This approach is based on measurements of the amplitude using a scalar network analyzer and retrieval of the phase from the amplitude data using a Hilbert transform relationship. Extensive propagation data are collected in a frequency range of 1 to 12 GHz in two buildings on Virginia Tech campus. Using the data, channel characterization results are obtained and compared to those based on time-domain measurements. Some statistical results for small-scale fading, path loss exponent, and signal quality are presented. This comparison validates the accuracy of measured results for the UWB measurement campaign. The measured data also reaffirms the immunity of UWB propagation to small-scale fading which is present in narrowband wireless communication systems. In addition to channel propagation measurements, signal distortions in UWB links, due to bandwidth limitations of antenna characteristics as well as the dispersive behavior of building materials, are also examined. In particular, the distortion of radiated signals by TEM horn antennas along off-boresight directions are studied experimentally. Furthermore, pulse distortions resulting from propagation through dispersive walls are demonstrated by simulation. The roles of receive-transmit antennas in a UWB link are examined, and the requirements for gain, input impedance, polarization, and phase of the radiated signal necessary for minimization of signal distortions are pointed out. / Master of Science

The traditional way of increasing capacity in a wirelesscommunication system has been cell splitting and fixedchannel-allocation based on prediction tools. However, theplanning complexity increases rapidly with the number of cellsand the method is not suitable for the large temporal andspatial traffic variations expected in the future. A lot ofresearch has therefore been performed regarding adaptivechannel allocation, where a channel can be used anywhere aslong as the signal-to-interference ratio (SIR) is acceptable. Acommon opinion is that these solutions must be decentralizedsince a centralized one would be overly complex. In this thesis, we study the locally centralizedbunch conceptfor radio resource management (RRM) in aManhattan environment and show that it can give a very highcapacity both for outdoor users and for indoor users covered byoutdoor base stations. We show how measurement limitations anderrors affect the performance and wepropose methods to handlethese problems, e.g. averaging of measured values, robustchannel selection algorithms, and increased SIR margins. Wealso study the computational and signaling complexities andshow that they can be reduced by splitting large bunches, usingsparse matrix calculations, and by using a simplified admissionalgorithm. However, a reduction of the complexity often means areduction of the system capacity. The measurements needed for RRM can also be used to find amobile terminal's geographical position. We propose and studysome simple yet accurate methods for this purpose. We alsostudy if position information can enhance RRM as is oftensuggested in the literature. In the studied scenario, thisinformation seems to be of limited use. One possible use is toestimate the mobile user's speed, to assist handover decisions.Another use is to find the location of user hotspots in anarea, which is beneficial for system planning. Our results show that the bunch concept is a promisingcandidate for radio resource management in future wirelesssystems. We believe that the complexity is manageable and themain price we have to pay for high capacity is frequentreallocation of connections. <b>Keywords:</b>bunch concept, radio resource management,network-assisted resource management, base station selection,dynamic channel allocation, DCA, channel selection,least-interfered, interference avoidance, interferenceaveraging, handover, power control, path-loss measurements,signal strength, link-gain matrix, TD-CDMA, UTRA TDD, Manhattanscenario, microcells, mobile positioning, position accuracy,trilateration, triangulation, speed estimation

<p>The traditional way of increasing capacity in a wirelesscommunication system has been cell splitting and fixedchannel-allocation based on prediction tools. However, theplanning complexity increases rapidly with the number of cellsand the method is not suitable for the large temporal andspatial traffic variations expected in the future. A lot ofresearch has therefore been performed regarding adaptivechannel allocation, where a channel can be used anywhere aslong as the signal-to-interference ratio (SIR) is acceptable. Acommon opinion is that these solutions must be decentralizedsince a centralized one would be overly complex.</p><p>In this thesis, we study the locally centralized<i>bunch concept</i>for radio resource management (RRM) in aManhattan environment and show that it can give a very highcapacity both for outdoor users and for indoor users covered byoutdoor base stations. We show how measurement limitations anderrors affect the performance and wepropose methods to handlethese problems, e.g. averaging of measured values, robustchannel selection algorithms, and increased SIR margins. Wealso study the computational and signaling complexities andshow that they can be reduced by splitting large bunches, usingsparse matrix calculations, and by using a simplified admissionalgorithm. However, a reduction of the complexity often means areduction of the system capacity.</p><p>The measurements needed for RRM can also be used to find amobile terminal's geographical position. We propose and studysome simple yet accurate methods for this purpose. We alsostudy if position information can enhance RRM as is oftensuggested in the literature. In the studied scenario, thisinformation seems to be of limited use. One possible use is toestimate the mobile user's speed, to assist handover decisions.Another use is to find the location of user hotspots in anarea, which is beneficial for system planning.</p><p>Our results show that the bunch concept is a promisingcandidate for radio resource management in future wirelesssystems. We believe that the complexity is manageable and themain price we have to pay for high capacity is frequentreallocation of connections.</p><p><b>Keywords:</b>bunch concept, radio resource management,network-assisted resource management, base station selection,dynamic channel allocation, DCA, channel selection,least-interfered, interference avoidance, interferenceaveraging, handover, power control, path-loss measurements,signal strength, link-gain matrix, TD-CDMA, UTRA TDD, Manhattanscenario, microcells, mobile positioning, position accuracy,trilateration, triangulation, speed estimation</p>