Consumer product invention: some developmental, economic & consumer aspects

This study of the British Bicycle and Domestic Radio Receiver industries produced a model of invention/product design having the following features: Invention depended mainly on the combined effect of three factors, each with changing significance over a three-stage life cycle. Technology Factor: Induced a cumulative sequence of inventions to improve product performance, of various origins (ideas, problems, techno-transfers or science). This factor most important in the first Incubation stage, of equal importance in second Early Growth stage and of incremental importance in final Mature stage. Economic Factor: Induced invention to suit market, mainly for cheaper, lower performance products but also for superlative models. This factor inoperative at Incubation stage, very important at Early Growth stage and important at Mature stage. Consumer Factor: Induced invention to make products more appealing to consumer; for simpler/automatic operation, greater reliability, accessories and new uses. This factor inoperative at Incubation stage, important at Early Growth stage and supremely important at Mature stage. Product life-cycle pattern a sequence of new models subsequently improved until an basic satisfactory design achieved, later incrementally improved. Empirical invention often systematic and as important as scientific invention; science often used to define design problem. Peak invention in Early Growth stage to explore all technical possibilities, design trade-offs and for market share. Invention and Demand: No direct and proportional relationship. Initial demand due to novelty appeal of function, subsequent rapid increased demand due to better technical product performance, lower product prices and increased income-related purchasing power. After market saturation demand declined despite better, sometimes radical, designs; as consumers sought other new products

Low-Power Wake-Up Receivers

The Internet of Things (IoT) is leading the world to the Internet of Everything (IoE), where things, people, intelligent machines, data and processes will be connected together. The key to enter the era of the IoE lies in enormous sensor nodes being deployed in the massively expanding wireless sensor networks (WSNs). By the year of 2025, more than 42 billion IoT devices will be connected to the Internet. While the future IoE will bring priceless advantages for the life of mankind, one challenge limiting the nowadays IoT from further development is the ongoing power demand with the dramatically growing number of the wireless sensor nodes. To address the power consumption issue, this dissertation is motivated to investigate low-power wake-up receivers (WuRXs) which will significantly enhance the sustainability of the WSNs and the environmental awareness of the IoT. Two proof-of-concept low-power WuRXs with focuses on two different application scenarios have been proposed. The first WuRX, implemented in a cost-effective 180-nm CMOS semiconductor technology, operates at 401−406-MHz band. It is a good candidate for application scenarios, where both a high sensitivity and an ultra-low power consumption are in demand. Concrete use cases are, for instance, medical implantable applications or long-range communications in rural areas. This WuRX does not rely on a further assisting semiconductor technology, such as MEMS which is widely used in state-of-the-art WuRXs operating at similar frequencies. Thus, this WuRX is a promising solution to low-power low-cost IoT. The second WuRX, implemented in a 45-nm RFSOI CMOS technology, was researched for short-range communication applications, where high-density conventional IoT devices should be installed. By investigation of the WuRX for operation at higher frequency band from 5.5 GHz to 7.5 GHz, the nowadays ever more over-traffic issues that arise at low frequency bands such as 2.4 GHz can be substantially addressed. A systematic, analytical research route has been carried out in realization of the proposed WuRXs. The thesis begins with a thorough study of state-of-the-art WuRX architectures. By examining pros and cons of these architectures, two novel architectures are proposed for the WuRXs in accordance with their specific use cases. Thereon, key WuRX parameters are systematically analyzed and optimized; the performance of relevant circuits is modeled and simulated extensively. The knowledge gained through these investigations builds up a solid theoretical basis for the ongoing WuRX designs. Thereafter, the two WuRXs have been analytically researched, developed and optimized to achieve their highest performance. Proof-of-concept circuits for both the WuRXs have been fabricated and comprehensively characterized under laboratory conditions. Finally, measurement results have verified the feasibility of the design concept and the feasibility of both the WuRXs

Energy-Efficient Wake-up Receivers for 915-MHz ISM Band Applications

Wake-up receiver (WuRx) is a well-known approach for optimizing the latency and power consumption of ultra-low power transceivers in wireless sensor nodes. Tuned RF (TRF) or Envelope Detection architecture is an appropriate topology for short-range Wireless Body Area Network (WBAN) applications, where achieving a very high sensitivity is not a priority. However, the demand for an improved sensitivity gets emphasized for longer transmission ranges. Regardless of the application, considering the existing trade-off between the power and sensitivity, design techniques and novel architectures are usually employed to optimize the power-sensitivity product. Moreover, considering the negative impact of higher data rate on the sensitivity, the energy-sensitivity product can be a more reasonable figure of merit when comparing WuRx designs. In this thesis, the RF-subsampling architecture has been combined with the TRF receiver architecture as a first approach for improving the power-sensitivity product. The overall power consumption is reduced as a result of employing the subsampling topology with a low-frequency local oscillator (LO). Post layout simulations show that the proposed WuRx draws only 56 μA from a 0.5 V supply and exhibits an input sensitivity of -70 dBm for a data rate of 100 kbps. The chip occupies an area of 0.15 mm2 and is fabricated with TSMC 90nm CMOS technology. Another major contribution of this work is to propose and implement a novel dual-mode ultra-low-power WuRx based on the subsampling topology, which not only reduces the overall power consumption but also optimizes the energy-sensitivity product of the receiver. During the typical mode of operation known as the Monitoring (MO) mode, the start frame bits are received at a rate of as low as 10 kbps. Having received the true preamble bits in the MO mode, the remaining wake-up pattern bits are received at a higher rate of 200 kbps during the Identifier (ID) mode. By lowering the gain of the front-end amplifier in the MO mode, the power dissipation is reduced, which in turn causes an increase in the overall noise figure of the receiver. However, adequate sensitivity and hence an optimized energy-sensitivity product is maintained by intentionally lowering the data rate as well as the detection bandwidth of the receiver in the MO mode. The proposed wake-up receiver has been designed and fabricated in IBM 130 nm technology with a core size of about 0.2 mm2 for the target frequency range of 902-928 MHz. The measured results show that the proposed dual-mode receiver achieves a sensitivity of -78.5 dBm and -75 dBm while dissipating an average power of 16.4 µW and 22.9 µW during MO and ID modes, respectively

GNSS Visibility and Performance Implications for the GENESIS Mission

The GENESIS mission prepared for launch in 2027 integrates the four space-geodetic techniques on a single spaceborne platform in medium Earth orbit. With its unique observations and alternative tie concepts, the mission aims to contribute to an improved accuracy and homogeneity of future terrestrial reference system realizations. To assess the expected contribution of Global Navigation Satellite System (GNSS) tracking, a comprehensive GNSS coverage analysis is performed based on detailed link-budget simulations, taking into account the best available gain patterns and signal-specific transmit power estimates derived for this work from measurements of a high-gain dish antenna. The benefit of different receiver antenna concepts for the GENESIS spacecraft is assessed and it is demonstrated that a single-antenna system with either a nadir-looking or side-looking boresight is a viable alternative to the dual-antenna configuration considered in initial mission studies. Compared to terrestrial users and missions in low Earth orbit, GENESIS will collect GNSS signals transmitted at up to two times larger off-boresight angles. Only limited information on the actual transmit antenna phase patterns is presently available in this region, which hampers a quantitative assessment of the expected measurement and orbit determination accuracy. As such, a comprehensive release of manufacturer calibrations is encouraged for all blocks of GPS and Galileo satellites. In parallel, a need for in-flight characterization and calibration of the GNSS transmit antennas for off-boresight angles of up to 30 deg using observations of the GENESIS mission itself is expected. The impact of such calibrations on the overall quality of terrestrial reference frame parameters will need to be assessed in comprehensive simulations of global GNSS network solutions with joint processing of terrestrial and GENESIS GNSS observations

Modular Nonlinear Characterization System and Large-Signal Behavioral Modelling of Unmatched Transistors for Streamlined Power Amplifier Design

This thesis provides a comprehensive approach to the characterization and modelling of large-signal nonlinear RF/microwave devices, circuits and systems. This research is moti- vated by the increased linearity and power-efficiency requirements of modern power ampli- fier technology for wireless communications. For instance, maximizing the power amplifier’s efficiency can only be achieved by operating RF transistors under strong nonlinear condi- tions, however this is contradictory to maximizing PA linearity. Simultaneously designing for efficiency and linearity is a challenging trade-off in today’s fragmented design process, therefore the advancement of computer-aided design (CAD) tools is essential for achieving an optimal solution. The successful and effective CAD tool based PA design relies on the availability of accurate nonlinear models to mimic the electro-thermal behaviour of RF transistors. The accuracy of these models depends on three factors: 1. The formulation of the model. 2. The model extraction procedure. 3. The accuracy of the measurement data. While prior work focuses separately on the improved model formulations or improving characterization accuracy, this thesis provides a comprehensive analysis of all three factors. This thesis proposes a modular large-signal RF device characterization system, and a non- linear behavioral model capable of handling strongly nonlinear unmatched RF transistors, each necessary to streamline the design process and achieve a first-pass PA design. iii As a first step, a large-signal characterization system has been developed to measure the multi-harmonic frequency response of RF transistors and has the ability to i) Perform high-power measurements, ii) Characterize unmatched transistors, iii) Operate the DUT under any possible operating condition, iv) Synthesize any multi-harmonic stimulus, and v) Reconstruct the time-domain I/V waveforms at the ports of the DUT. The proposed characterization system eliminates fragmentation between measurement and simulation environments by providing seamless integration with Harmonic Balance simulations. This provides a common framework that integrates all steps of the PA design process from device-level characterization, to circuit-level measurement and validation. This system is implemented using modular instruments consisting of mixer-based receivers, arbitrary waveform generators, impedance tuners, and a multi-harmonic phase-coherent reference source. It also integrates sequential calibration routines to provide receiver, port match, and source-power corrections to the DUT measurement plane and measurement routines for automated data collection. The second part of the thesis researches black-box frequency-domain behavioral mod- els that can approximate strongly nonlinear, unmatched devices. Our investigation yielded two complimentary solutions to ensure the targeted modelling accuracy. First, improving the accuracy of a first-order expansion-based Poly-Harmonic Distortion (PHD) model by 5dB, in terms of Normalized Mean-Squared Error (NMSE), by minimizing multi-harmonic reflections that artificially increase the order of the nonlinear system. While this addresses the fictitious need for higher-order models due to the deficiencies in the model extraction procedure, strongly nonlinear devices will require high-order models to achieve the targeted accuracy over a larger measurement distribution. Hence, a variable order Multi-Harmonic Volterra (MHV) model is proposed to extend the PHD model formulation to strong non- linear devices. This model is extracted by utilizing the proposed characterization system to extract higher-order multi-variate model coefficients not included in the PHD model. The resulting model improves DC drain current prediction by 5dB and improves funda- mental output-power prediction by 2dB. The MHV model improves the vector power-gain prediction by 3.4dB in realistic PA design applications, thereby providing better emulation of linearization techniques within a simulation environment. Finally, a concurrent dual-band PA design is studied as an example of how the pro- iv posed nonlinear characterization system and behavioural modelling approach can be used to enable complex PA designs. First, a 10W Class-AB PA is designed using dual-band matching-network theory, however it is difficult to implement because the design technique does not control the matching fractional bandwidth as a design parameter. Therefore, an alternative Class-J 45W dual-band PA was designed using a low-impedance matching network, combined with a trans-impedance dual-band filter. Although the dual-band PA can achieve comparable performance to an equivalent single-band PA at each separate fre- quency, further development of characterization, modeling, and circuit design techniques is needed to achieve high-efficiency during concurrent operation

Investigation of Shadow Matching for GNSS Positioning in Urban Canyons

All travel behavior of people in urban areas relies on knowing their position. Obtaining position has become increasingly easier thanks to the vast popularity of ‘smart’ mobile devices. The main and most accurate positioning technique used in these devices is global navigation satellite systems (GNSS). However, the poor performance of GNSS user equipment in urban canyons is a well-known problem and it is particularly inaccurate in the cross-street direction. The accuracy in this direction greatly affects many applications, including vehicle lane identification and high-accuracy pedestrian navigation. Shadow matching is a new technique that helps solve this problem by integrating GNSS constellation geometries and information derived from 3D models of buildings. This study brings the shadow matching principle from a simple mathematical model, through experimental proof of concept, system design and demonstration, algorithm redesign, comprehensive experimental tests, real-time demonstration and feasibility assessment, to a workable positioning solution. In this thesis, GNSS performance in urban canyons is numerically evaluated using 3D models. Then, a generic two-phase 6-step shadow matching system is proposed, implemented and tested against both geodetic and smartphone-grade GNSS receivers. A Bayesian technique-based shadow matching is proposed to account for NLOS and diffracted signal reception. A particle filter is designed to enable multi-epoch kinematic positioning. Finally, shadow matching is adapted and implemented as a mobile application (app), with feasibility assessment conducted. Results from the investigation confirm that conventional ranging-based GNSS is not adequate for reliable urban positioning. The designed shadow matching positioning system is demonstrated complementary to conventional GNSS in improving urban positioning accuracy. Each of the three generations of shadow matching algorithm is demonstrated to provide better positioning performance, supported by comprehensive experiments. In summary, shadow matching has been demonstrated to significantly improve urban positioning accuracy; it shows great potential to revolutionize urban positioning from street level to lane level, and possibly meter level

IF-level signal-processing of GPS and Galileo Radionavigation signals using MATLAB/Simulink®: Including Effects of Interference and Multipath

Open-source GNSS simulator models are rare and somewhat difficult to find. Therefore, Laboratory of Electronics and Communications Engineering in the former Tampere University of Technology (and now Tampere University, Hervanta Campus) has took it upon itself to develop, from time to time, a free and open-source simulator model based on MATLAB/Simulink® for signal processing of a carefully selected set of GNSS radionavigation signals, namely, Galileo E1, Galileo E5, GPS L1, and GPS L5. This M.Sc. thesis is the culmination of those years which have been spent intermittently on research and development of that simulator model. The first half of this M.Sc. thesis is a literature review of some topics which are believed to be of relevance to the thesis’s second half which is in turn more closely associated with documenting the simulator model in question. In particular, the literature review part presents the reader with a plethora of GNSS topics ranging from history of GNSS technology to characteristics of existing radionavigation signals and, last but not least, compatibility and interoperability issues among existing GNSS constellations. While referring to the GNSS theory whenever necessary, the second half is, however, mainly focused on describing the inner-workings of the simulator model from the standpoint of software implementations. Finally, the second half, and thereby the thesis, is concluded with a presentation of various statistical results concerning signal acquisition’s probabilities of detection and false-alarm, in addition to signal tracking’s RMSE

Satellite Laser Ranging in the 1990s: Report of the 1994 Belmont Workshop

An international network of 43 stations in 30 countries routinely collects satellite ranging data which is used to study the solid Earth and its interactions with the oceans, atmosphere, and Moon. Data products include centimeter accuracy site positions on a global scale, tectonic plate motions, regional crustal deformation, long wavelength gravity field and geoid, polar motion, and variations in the Earth's spin rate. By calibrating and providing precise orbits for spaceborne microwave altimeters, satellite laser ranging also enables global measurement of sea and ice surface topography, mean sea level, global ocean circulation, and short wavelength gravity fields and marine geoids. It provides tests of general relativity and a means or subnanosecond time transfer. This workshop was convened to define future roles and directions in satellite laser ranging

Experimental Investigation Of Ultrawideband Wireless Systems: Waveform Generation, Propagation Estimation, And Dispersion Compensation

Ultrawideband (UWB) is an emerging technology for the future high-speed wireless communication systems. Although this technology offers several unique advantages like robustness to fading, large channel capacity and strong anti-jamming ability, there are a number of practical challenges which are topics of current research. One key challenge is the increased multipath dispersion which results because of the fine temporal resolution. The received response consists of different components, which have certain delays and attenuations due to the paths they took in their propagation from the transmitter to the receiver. Although such challenges have been investigated to some extent, they have not been fully explored in connection with sophisticated transmit beamforming techniques in realistic multipath environments. The work presented here spans three main aspects of UWB systems including waveform generation, propagation estimation, and dispersion compensation. We assess the accuracy of the measured impulse responses extracted from the spread spectrum channel sounding over a frequency band spanning 2-12 GHz. Based on the measured responses, different transmit beamforming techniques are investigated to achieve high-speed data transmission in rich multipath channels. We extend our work to multiple antenna systems and implement the first experimental test-bed to investigate practical challenges such as imperfect channel estimation or coherency between the multiple transmitters over the full UWB band. Finally, we introduce a new microwave photonic arbitrary waveform generation technique to demonstrate the first optical-wireless transmitter system for both characterizing channel dispersion and generating predistorted waveforms to achieve spatio-temporal focusing through the multipath channels