Ultra wide-band (UWB) technology is considered one of the very promising wireless technologies in the new millennium. This increases the demand on designing UWB antennas that meet the requirements of different UWB systems. In this dissertation, different UWB antennas are proposed such as an antenna that covers almost the entire UWB bandwidth, 3.5-11 GHz, as defined by the federal communication commission (FCC). This antenna has a size of 50×40×1.5mm3. Miniaturized worldwide UWB antennas are also introduced. Miniaturized worldwide UWB antennas that have compact sizes of (30×20×1.5) mm3, and (15×15×1.5) mm3 are also investigated. The designed worldwide UWB antennas cover the UWB spectrums defined by the electronic communication committee (ECC), 6-8.5 GHz, and the common worldwide UWB spectrum, 7.4-9 GHz. A system consisting of two identical antennas (transmitter and receiver) is built in the Antennas and Propagation Lab at Southern Illinois University Carbondale (SIUC) to test the coupling properties between every two identical antennas. The performance of that system is analyzed under different ii conditions to guarantee that the transmitted signal will be correctly recovered at the receiver end. The designed UWB antennas can be used in many short range applications such as wireless USB. Wireless USB is used in PCs, printers, scanners, laptops, MP3 players, hard disks and flash drives. A new technique is introduced to widen the impedance bandwidth of dielectric resonator antennas (DRAs). DRA features compactness, low losses, and wideband antennas. Different compact UWB DRAs are investigated in this dissertation. The designed DRAs cover a wide range of frequency bands such as, 6.17-24GHz, 4.23-13.51GHz, and 4.5-13.6GHz. The designed DRAs have compact sizes of 1×1×1.5cm3, 0.9×0.9×1.32cm3, 0.6×0.6×1cm3, and 0.6×0.6×0.9cm3; and cover the following frequency bands 4.22-13.51GHz, 4.5-13.6GHz, 6.1-23.75GHz, and 6.68-26.7GHz; respectively. The proposed DRAs may be used for applications in the X, Ku and K bands such as military radars and unmanned airborne vehicles (UAV).

Over the last ten years, Ultra-Wide Band (UWB) technology has attracted tremendous research attention. Frequency allocation of 3.1-10.6 GHz for UWB application by FCC made it apparent that UWB will be the technology for future wireless high speed communication applications. With the promise of high data rates (high channel capacity), UWB also offers advantages such as communication security, high multi-path resolution, good penetration capability, ability to coexist with other communication schemes in the same band, and finally, circuit simplicity. The theoretical advantages of UWB has made it a great candidate for short distance communications, however, UWB communications have many challenges, for example, sub-nanosecond pulse generation, timing sensitivity of modulation and synchronization, flat antenna performance over a wide bandwidth, effect of existing systems on UWB systems. In order to experiment with various UWB modulation schemes, and to study transmitter and receiver structures, an accurate channel model need be established. In this dissertation, our first contribution is to evaluate and implement two major statistical channel models. The first model is proposed by AT\&T Labs and is in the form of an autoregressive IIR filter. Although this is an accurate channel model to represent UWB behavior, it is proposed before the allocation of 3.1-10.6 GHz frequency band, hence, it could not simulate the correct frequency spectrum. The second model is proposed by Saleh and Valenzuela, which has been widely accepted by UWB community to be the most accurate channel model for UWB systems. Recently disbanded task group 802.15.3a which was assigned to standardize a UWB communication scheme has also accepted the latter model. Our second contribution is to derive optimal pulses for PPM signals. Using the accurate channel model in computer simulations, we experimented on various UWB communication schemes. We found that the traditional UWB pulses being used in pulse position modulated UWB systems did not perform optimally. A set of optimized UWB pulses and the methodology to calculate optimal pulses for any modulation index for PPM systems have been proposed in this dissertation. It is found that the optimal pulse can improve the performance of UWB systems by as much as 0.7 dB. With the PPM pulse optimization, the theoretical performance limits of PPM systems are derived. The third contribution from this dissertation is to design near optimal practical implementable receiver structures. Some of the results obtained from PPM pulse optimization are found to be theoretical and not practical. More practical approach to the receiver structures were needed for industrial interest. We proposed simple sub-optimal receiver structures that are able to perform only a few dB less than the optimal receivers are proposed. These simple, low-cost receiver structures are strong alternatives to the complex traditional optimal receivers.

Cette thèse s’inscrit dans le projet de communication à proximité aux départements Electronique et Physique et Communications, Images et Traitement de l’Information de l’Institut Télécom Sud Paris. Le projet comporte la mise au point d’un récepteur basé sur une méthode de détection pseudo-cohérente des signaux Ultra Large Bande à double impulsion (TR-UWB), méthode désignée par Time Delayed Sampling and Correlation (TDSC). La première partie de ce document comporte la réalisation d’une plate-forme modulaire de communication UWB basée sur le système de détection TDSC. Cette plate-forme comporte une puce CMOS 0.35μm conçue précédemment au laboratoire EPH. Elle offre la possibilité d’enregistrer des signaux TR-UWB réels et de réaliser des tests de fonctionnement. La deuxième partie est une étude approfondie du récepteur utilisant la méthode TDSC. La détection des signaux UWB et la procédure de synchronisation sont évalués en utilisant les signaux réels acquis à partir de la plate-forme. Un ensemble de tests ont été menés avec des signaux en bande de base et des signaux transposés en fréquence, dans les deux cas en transmission sur câble puis par radio. Les résultats ont permis de valider la détection et le principe de la synchronisation. La troisième partie est une proposition d’estimation de la distance entre deux dispositifs d’un réseau radio UWB utilisant un récepteur TDSC, pour une localisation en intérieur. L’étude fait la synthèse de plusieurs propositions et expérimentations et conduit à la définition des meilleurs critères pour une mesure du temps d’arrivée (TOA) et son implémentation pratique sur un récepteur TDSC / This thesis is part of the Electronics and Physics (EPH) department’s research work at Institut Telecom SudParis in collaboration with the Information, Images and Information Processing (CITI) Department. The project included the development of a receiver architecture called Time Delayed Sampling and Correlation (TDSC) that works with Transmitted Reference Ultra Wideband signals (TR-UWB), and which could achieve a good performance without channel estimation. The first part of this work included the design of a modular UWB communication system based on the TDSC method. This platform uses a 0.35μm CMOS chip conceived by the EPH laboratory. This gives the possibility to record real TR-UWB signals and to achieve functional tests. A second part of the thesis was to deepen the use of the TDSC method for detection of UWB signals and the synchronization procedure of the receiver using real signals acquired by the platform. A series of tests were conducted in this regard by using baseband signals as well as frequency translated signals, through cable channels and radio transmission. The results let us validate the TDSC detection and the synchronization procedure. Finally, a third line of work was the study and development of a distance estimation proposal based on the time of arrival (TOA) of TR-UWB signals, for indoor localization purposes. The study included a synthesis of several proposals and experimental works. Simulations were made and compared with other methods. Experimental results and their good convergence with the simulations let conclude that the proposal is a feasible solution to the measurement of the TOA, based on a TR-UWB receiver with low-complexity architecture

Master of Science / Department of Electrical and Computer Engineering / William B. Kuhn / Excitement about using ultra-wideband (UWB) technology for networking has grown considerably over the last few years. UWB has several strengths, including high data rates, security, and robustness in multipath environments. Despite these benefits, UWB has been scrutinized for its potential to interfere with narrowband technologies like the Global Positioning System (GPS). Until recently, much of the literature about UWB and GPS compatibility has been published on the basis of theoretical analysis alone. We have investigated the compatibility of UWB and GPS signals using theoretical analysis as well as laboratory measurements with a consumer GPS receiver and a WiMedia UWB device. We conclude from our tests that the UWB device does emit interference in the GPS L1 band, but the interference is low enough that careful antenna and chipset placement could allow UWB and GPS radios to coexist in a single product. Also, we have evaluated several UWB antennas to determine their fitness for use in a handheld electronic product. We find that the antennas’ gain pattern and return loss do not have a significant effect upon the data throughput of the UWB system. Thus, we infer that the indoor environment is highly dispersive and that the UWB system is able to exploit multipath propagation. Furthermore, we have created a link budget to estimate the distances over which a WiMedia UWB system should be capable of operating. In the lab, the maximum distances over which the UWB device actually operated were about half of what we expected. This suggests that the path loss exponent and standard deviation of fading could be higher than we expected or that the implementation loss of the UWB chipset is quite high. Currently the market potential of UWB is uncertain. If UWB is embraced by the consumer electronics industry as the wireless platform of choice for Certified Wireless USB and high-speed Bluetooth technology, it could become a ubiquitous networking feature for electronic products such as phones, laptops, cameras, media players, and portable navigation devices. In this thesis, we strive to provide information that would be useful when undertaking a GPS and UWB radio integration project.

Due to wealth of advantages offered by short range ultra wideband (UWB) technology, such as capacity improvement, fading reduction and localization, it has gathered a considerable attention. Distinct UWB qualities also pose many system design challenges like difficulties in using digital processing, complex channel estimation and different propagation characteristics. The main objective of the thesis is to develop and evaluate efficient modulation and detection schemes for impulse radio (IR) UWB with a focus on wireless sensor networks characterized by low cost and low power consumption. The content of the thesis comprises of five parts. In Part I, a coherent RAKE and non-coherent energy detector (ED) and transmitted reference (TR) receivers are examined and their bit-error-rate (BER) performance is evaluated using channels measured in an industrial environment. In specific, selective RAKE (SRake) and partial RAKE (PRake) for both maximal ratio combining (MRC) and equal gain combining (EGC) are compared. Based on the analysis and simulation results, it is concluded the SRake with EGC is to be preferred, whereas the best complexity/performance trade-off is provided by the ED based receivers. Part II presents several signaling and detection schemes; the proposed schemes are recursive TR (R-TR), dual-doublet TR (DDTR), doublet-shift TR (DSTR) and binary pulse position modulation (BPPM)/DSTR. Analysis and simulations verify that the proposed schemes may be preferred over the conventional TR in terms of BER, energy efficiency and/or implementation complexity. Part III presents a non-coherent kurtosis detector (KD) and a fourth-order detector (FD), which can discriminate between Gaussian noise and non-Gaussian IR-UWB signals by directly estimating the fourth-order moment of the received signal. Empirical evaluations and simulations using channel measurements conducted in a corridor, an office and a laboratory environment verify that performance of the proposed FD receiver is slightly better than the ED in the low SNR region and its performance improves as the SNR increases. Part IV presents a robust weighted ED (WED) in which the weighting coefficients are estimated adaptively based on the received stochastic data. Simulation results confirm that performance of the proposed weight estimation method is close to that of a data-aided (DA) scheme. Finally, Part V focuses on a multi-user scenario and develops a weighted code-multiplexed TR (WCM-TR) receiver employing the robust adaptive weight estimation scheme. Secondly, a BPPM/CM-TR UWB system is presented to mitigate inter-frame interference (IFI) and multi-user interference (MUI) from other asynchronous users. The BPPM/CM-TR system is 3 dB energy-efficient and improves the BER performance by mitigating MUI/IFI in the high SNR region, while for the low SNR case and single-user scenario, a dual-mode BPPM/CM-TR system is suggested

In this report the feasibility of using a dual-tag setup in an indoor positioning system was investigated. The reason for the dual-tag setup was to be able to estimate both position and orientation. The system was designed using UWB-technology, with an time of flight trilateration algorithm to calculate the position. The orientation was then estimated from the relative position between the two tags. The system was tested both with stationary tags, but also with the tags moving along two paths. These tests were conducted for different separation distance between the tags, namely 20 cm, 30 cm and 40 cm. The result was that the mean position error for stationary tags was less than 8 cm for all separations and the mean orientation error was less than 3$^\circ$ for all separations. For the moving tag tests a decrease of the error in orientation of about 30 \% could be observed for a separation of 30 and 40 cm compared to 20 cm. However this difference is small in absolute values so more tests are needed to draw any conclusion about whether 30 and 40 cm tag separation performs better than 20 cm tag separation. The performance of the system could also be increased further by optimizing the anchor placement as well as the calibration of the antenna delays of the UWB-modules.

"Precise Tracking of Things (PToT) using RF signals has posed a serious challenge in an indoor environment. The precision localization information is an enabler for better coordinated-tasks and is essential for a successful launch of many emerging applications. PToT relies on two principal components, a novel navigation (tracking) algorithm, and a hybrid 3D fingerprint database. In this dissertation, we begin by using the two widely known ranging techniques, Time Of Arrival (TOA) associated with Ultra-wideband (UWB) and Received Signal Strength (RSS) with WiFi signals. First, we use the theoretical models derived from empirical measurement of TOA and RSS to analyze the performance of hybrid (WiFi & UWB) cooperative localization accuracy in a multi-robot operation in a typical office environment. To measure the performance of this hybrid localization, we derive a mathematical formulation for the Crame ́r-Rao-Lower- Bound (CRLB). The hybrid method shows more accuracy over WiFi-only approach. In achieving more precision, we extend our work. Second, we introduce a novel approach, a Kernel Method Particle Filter (KMPF) for tracking and predicting the position by accessing the information created by hybrid 3D fingerprint database. We derive the mathematical and statistical framework for the Particle Filter based on the statistical assumptions about the behavior of channel models. We also describe the formation of one of the necessary PToT component, a 3D fingerprint database. We compare the performance of the KMPF against the CRLB using WiFi signal channel models."

"This thesis presents a real-time noncontact system that can monitor an infant's respiration and detect apnea when it occurs. For infants, bedside monitoring of respiratory signals using non-contact sensors is desirable at the hospital and for in-home care. Traditional approach employs acoustic sensors which can hardly detect infant breathing due to low SNR. In this thesis, a novel method is introduced by using a ultra-wideband (UWB) radar that obtains breathing signal from an infant's weak chest vibration. Furthermore, advanced signal processing techniques are proposed to monitor the breathing signal and to detect apnea. Since an infant may move in the crib, a location algorithm is applied periodically to track the current location of the infant's chest. An apnea warning is issued when the respiration is absent for a pre-defined period of time."

Falls are a cause of concern for the elderly since it can render a person immobile. A monitoring system can summon immediate aid by the automatic detection of fall events. The application of ultra-wideband (UWB) signals for a monitoring system was chosen due to its unique characteristics such as wide spectrum, immunity to interference, penetrability, and application for the detection of people. Part of this monitoring system is boundary detection with the purpose of isolating the location of fall events and to function as a mask to define an area of interest. A study of various localizing methods using measurements such as power, distance, and angle with ultra-wideband is presented. A frequency modulated continuous wave (FMCW) based system is an acceptable solution for boundary detection. A FMCW system measures distance with UWB signals. With the addition of a unique reflector, the system is able to identify the reflector via the return frequency-spectrum fingerprint. With distance and the addition angle measurements, the system can determine the boundary with a sensor located at a single location.

GPS denied environments cause each unmanned ground vehicle (UGV) in an autonomous convoy to lose positional accuracy which can lead to inoperability, or even damage. In order for autonomous convoy systems to fill the needs of any particular field, a well-performing system must be designed such that a convoy can operate in any environment. Ultra-wideband (UWB) radios are a proposed solution to GPS denied localization.The main objective of this research is to use UWB radios to localize a leader vehicle within a convoy situation while in a GPS denied environment.