Investigations of 5G localization with positioning reference signals

TDOA is an user-assisted or network-assisted technique, in which the user equipment calculates the time of arrival of precise positioning reference signals conveyed by mobile base stations and provides information about the measured time of arrival estimates in the direction of the position server. Using multilateration grounded on the TDOA measurements of the PRS received from at least three base stations and known location of these base stations, the location server determines the position of the user equipment. Different types of factors are responsible for the positioning accuracy in TDOA method, such as the sample rate, the bandwidth, network deployment, the properties of PRS, signal propagation condition, etc. About 50 meters positioning is good for the 4G/LTE users, whereas 5G requires an accuracy less than a meter for outdoor and indoor users. Noteworthy improvements in positioning accuracy can be achievable with the help of redesigning the PRS in 5G technology. The accuracy for the localization has been studied for different sampling rates along with different algorithms. High accuracy TDOA with 5G positioning reference signal (PRS) for sample rate and bandwidth hasn’t been taken into consideration yet. The key goal of the thesis is to compare and assess the impact of different sampling rates and different bandwidths of PRS on the 5G positioning accuracy. By performing analysis with variable bandwidths of PRS in resource blocks and comparing all the analyses with different bandwidths of PRS in resource blocks, it is undeniable that there is a meaningful decrease in the RMSE and significant growth in the SNR. The higher bandwidth of PRS in resource blocks brings higher SNR while the RMSE of positioning errors also decreases with higher bandwidth. Also, the number of PRS in resource blocks provides lower SNR with higher RMSE values. The analysis with different bandwidths of PRS in resource blocks reveals keeping the RMSE value lower than a meter each time with different statistics is a positivity of the research. The positioning accuracy also analyzed with different sample sizes. With an increased sample size, a decrease in the root mean square error and a crucial increase in the SNR was observed. From this thesis investigation, it is inevitable to accomplish that two different analyses (sample size and bandwidth) done in a different way with the targeted output. A bandwidth of 38.4 MHz and sample size N = 700 required to achieve below 1m accuracy with SNR of 47.04 dB

Técnicas avanzadas de geolocalización en redes UMTS

Las redes de comunicaciones móviles han evolucionado a un ritmo exponencial a lo largo de los últimos años. Este crecimiento ha acentuado la necesidad de disponer de herramientas que ayuden a la detección de problemas (troubleshooting), a la optimización y a la monitorización de estas redes. En este contexto es donde entran en juego los mapas geolocalizados, ya que ofrecen una manera sencilla, eficaz y visual de llevar a cabo estas tareas, además de proporcionar una alternativa de bajo coste a los drive tests. De este modo, y a partir de las trazas de las llamadas de los usuarios (call traces), surge la posibilidad de emplear diversas técnicas de geolocalización para estimar la posición de los eventos reportados por el dispositivo móvil. Naturalmente, las dos cuestiones más críticas para este enfoque son las precisión punto a punto y la calidad visual de los mapas. En esta tesis se analizan y desarrollan varios algoritmos avanzados de geolocalización para redes UMTS, aunque gran parte de los mismos pueden ser fácilmente extrapolados a redes LTE. Estos algoritmos se implementan dentro de herramientas autónomas para ser, posteriormente, evaluados y verificados mediante datos reales provenientes de redes móviles actualmente en servicio. La utilización de datos reales es un aspecto clave, puesto que proporciona una alta fiabilidad y robustez a los resultados y conclusiones extraídos. En primer lugar, se desarrolla una herramienta híbrida de geolocalización que combina diversos algoritmos y fuentes de información con el objetivo de establecer un compromiso entre mapas geolocalizados poblados y realistas, y una buena precisión punto a punto. Se definen un conjunto de procesos secuenciales que van introduciendo y combinando medidas de nivel de señal, medidas temporales, parámetros del Nodo B servidor y de los Nodos B vecinos, predicciones de señal, e incluso datos geográficos del terreno y el entorno. El resultado final es la posibilidad de generar mapas, por ejemplo de señal o de mejor celda servidora, que ofrecen gran cohesión y coherencia visual, además de una mejora de precisión gracias a la combinación de diferentes estrategias. En segundo instancia, se presenta una herramienta basada en la multilateración hiperbólica u OTDOA (Observed Time Difference of Arrival) para estimar, conjuntamente, tanto la posición de los usuarios como la diferencia de sincronización entre los Nodos B. Para ello, y a partir de los eventos Measurement Report que reportan el parámetro TM, esta técnica resuelve un problema de estimación de mínimos cuadrados no lineal a través de un método numérico iterativo. En particular, se analizan y comparan los métodos de Gauss-Newton, Levenberg-Marquardt y un nuevo Levenberg-Marquardt modificado surgido de este trabajo. Asimismo, se plantea una geometría espacial de cuatro sites, la configuración en estrella, que evita la aparición de mínimos locales. Como resultado, las modificaciones propuestas incrementan la precisión implícita en OTDOA, proporcionan rápida convergencia y alta robustez, y reducen el coste monetario general del método al no requerir de sistemas externos, tales como los LMUs, que recuperen previamente la sincronización. Finalmente, se detalla una técnica de compresión para ajustar de manera inteligente las posiciones estimadas de cualquier usuario dadas por diferentes estrategias de geolocalización, por ejemplo basadas en OTDOA, ángulo de llegada (AOA) o retardo de propagación (PD). La idea se centra en subir un nivel de abstracción, pasando de los eventos como entes independientes a los eventos que conforman una llamada, distinguiendo también si éstas son estáticas o dinámicas. En concreto, el método propuesto desplaza las posiciones hacia un ancla virtual calculada previamente según las áreas de confianza al 95% de cada evento geolocalizado. A su vez, estas regiones de confianza son computadas con simuladores en función de diversos parámetros de la red móvil y del propio evento. De este modo, se logra una notable mejora de precisión y mitigar los efectos adversos de distintas fuente de error, como puede ser el multitrayecto

A non-device specific framework for the development of forensic locational data analysis procedure for consumer grade small and embedded devices

Portable and wearable computing devices such as smart watches, navigation units, mobile phones, and tablet computers commonly ship with Global Navigation Satellite System (GNSS) supported locational awareness. Locational functionality is no longer limited to navigation specific devices such as satellite navigation devices and location tracking systems. Instead the use of these technologies has extended to become secondary functionality on many devices, including mobile phones, cameras, portable computers, and video game consoles. The increase in use of location aware technology is of use to forensic investigators as it has the potential to provide historic locational information. The evidentiary value of these devices to forensic investigators is currently limited due to the lack of available forensic tools and published methods to properly acquire and analyse these data sources. This research addresses this issue through the synthesis of common processes for the development of forensic procedure to acquire and interpret historic locational data from embedded, locationally aware devices. The research undertaken provides a framework for the generation of forensic procedure to enable the forensic extraction of historical locational data. The framework is device agnostic, relying instead on differential analysis and structured testing to produce a validated method for the extraction of locational history. This framework was evaluated against five devices, selected on a basis of market penetration, availability and a stage of deduplication. The examination of the framework took place in a laboratory developed specifically for the research. This laboratory replicates all identified sources of location data for the devices selected. In this case the laboratory is able to simulate cellular (2G and 3G), GNSS (NAVSTAR and GLONASS), and Wi-Fi locationing services. The laboratory is a closed-sky facility, meaning that the laboratory is contained within a faraday cage and all signals are produced and broadcast internally. Each selected device was run through a series of simulations. These simulations involved the broadcast of signals, replicating the travel of a specific path. Control data was established through the use of appropriate data recording systems, for each of the simulated location signals. On completion of the simulation, each device was forensically acquired and analysed in accordance with the proposed framework. For each experiment carried out against the five devices, the control and experimental data were compared. In this examination any divergence less than those expected for GNSS were ignored. Any divergence greater than this was examined to establish cause. Predictable divergence was accepted and non-predictable divergence would have been noted as a limitation. In all instances where data was recovered, all divergences were found to be predictable. Post analysis, the research found that the proposed framework was successful in producing locational forensic procedure in a non-device specific manner. This success was confirmed for all the devices tested

New mobile positioning techniques for LOS/NLOS environments and investigation of topology influence

The advent of wireless location technology and the increase in location-based services, has meant the need to investigate efficient network-based location methods becoming of paramount importance. Therefore, the interest in wireless positioning techniques has been increasing over recent decades. Among mobile positioning techniques, the Time of Arrival (TOA) and Time Difference of Arrival (TDOA) look promising. For the purpose of dealing with such technologies, some classic algorithms such as least square, most likelihood and Taylor method have been used to solve the estimation, which distinguishes the location. However, in real practice, there are certain factors that influence the level of location accuracy. The two most significant factors are cellular topologies and non-line-of-sight (NLOS) effect. This thesis reviews existing approaches and suggests innovative methods for both line-of-sight (LOS) and NLOS scenarios. A simulation platform is designed to test and compare the performances of these algorithms. The results of the simulation compared with actual position measurements demonstrate that the innovative approaches have high positioning accuracy. Additionally, this thesis demonstrates different types of cellular topologies and develops a simulation to show how the cellular topology affects the positioning quality level. Finally, this thesis implements an experiment to exhibit how the innovative algorithms perform in the real world

QoS constrained cellular ad hoc augmented networks

In this dissertation, based on different design criteria, three novel quality of service (QoS) constrained cellular ad hoc augmented network (CAHAN) architectures are proposed for next generation wireless networks. The CAHAN architectures have a hybrid architecture, in which each MT of CDMA cellular networks has ad hoc communication capability. The CAHAN architectures are an evolutionary approach to conventional cellular networks. The proposed architectures have good system scalability and high system reliability. The first proposed architecture is the QoS constrained minimum-power cellular ad hoc augmented network architecture (QCMP CAHAN). The QCMP CAHAN can find the optimal minimum-power routes under the QoS constraints (bandwidth, packet-delay, or packet-error-rate constraint). The total energy consumed by the MTs is lower in the case of QCMP CAHAN than in the case of pure cellular networks. As the ad hoc communication range of each MT increases, the total transmitted power in QCMP CAHAN decreases. However, due to the increased number of hops involved in information delivery between the source and the destination, the end-to-end delay increases. The maximum end-to-end delay will be limited to a specified tolerable value for different services. An MT in QCMP CAHAN will not relay any messages when its ad hoc communication range is zero, and if this is the case for all MTs, then QCMP CAHAN reduces to the traditional cellular network. A QoS constrained network lifetime extension cellular ad hoc augmented network architecture (QCLE CAHAN) is proposed to achieve the maximum network lifetime under the QoS constraints. The network lifetime is higher in the case of QCLE CAHAN than in the case of pure cellular networks or QCMP CAHAN. In QCLE CAHAN, a novel QoS-constrained network lifetime extension routing algorithm will dynamically select suitable ad-hoc-switch-to-cellular points (ASCPs) according to the MT remaining battery energy such that the selection will balance all the MT battery energy and maximizes the network lifetime. As the number of ASCPs in an ad hoc subnet decreases, the network lifetime will be extended. Maximum network lifetime can be increased until the end-to-end QoS in QCLE CAHAN reaches its maximum tolerable value. Geocasting is the mechanism to multicast messages to the MTs whose locations lie within a given geographic area (target area). Geolocation-aware CAHAN (GA CAHAN) architecture is proposed to improve total transmitted power expended for geocast services in cellular networks. By using GA CAHAN for geocasting, saving in total transmitted energy can be achieved as compared to the case of pure cellular networks. When the size of geocast target area is large, GA CAHAN can save larger transmitted energy

Adaptive Control

Adaptive control has been a remarkable field for industrial and academic research since 1950s. Since more and more adaptive algorithms are applied in various control applications, it is becoming very important for practical implementation. As it can be confirmed from the increasing number of conferences and journals on adaptive control topics, it is certain that the adaptive control is a significant guidance for technology development.The authors the chapters in this book are professionals in their areas and their recent research results are presented in this book which will also provide new ideas for improved performance of various control application problems

Interference Mitigation and Localization Based on Time-Frequency Analysis for Navigation Satellite Systems

Interference Mitigation and Localization Based on Time-Frequency Analysis for Navigation Satellite SystemsNowadays, the operation of global navigation satellite systems (GNSS) is imperative across a multitude of applications worldwide. The increasing reliance on accurate positioning and timing information has made more serious than ever the consequences of possible service outages in the satellite navigation systems. Among others, interference is regarded as the primary threat to their operation. Due the recent proliferation of portable interferers, notably jammers, it has now become common for GNSS receivers to endure simultaneous attacks from multiple sources of interference, which are likely spatially distributed and transmit different modulations. To the best knowledge of the author, the present dissertation is the first publication to investigate the use of the S-transform (ST) to devise countermeasures to interference. The original contributions in this context are mainly: • the formulation of a complexity-scalable ST implementable in real time as a bank of filters; • a method for characterizing and localizing multiple in-car jammers through interference snapshots that are collected by separate receivers and analysed with a clever use of the ST; • a preliminary assessment of novel methods for mitigating generic interference at the receiver end by means the ST and more computationally efficient variants of the transform. Besides GNSSs, the countermeasures to interference proposed are equivalently applicable to protect any direct-sequence spread spectrum (DS-SS) communication

Physical Layer Challenges and Solutions in Seamless Positioning via GNSS, Cellular and WLAN Systems

As different positioning applications have started to be a common part of our lives, positioning methods have to cope with increasing demands. Global Navigation Satellite System (GNSS) can offer accurate location estimate outdoors, but achieving seamless large-scale indoor localization remains still a challenging topic. The requirements for simple and cost-effective indoor positioning system have led to the utilization of wireless systems already available, such as cellular networks and Wireless Local Area Network (WLAN). One common approach with the advantage of a large-scale standard-independent implementation is based on the Received Signal Strength (RSS) measurements.This thesis addresses both GNSS and non-GNSS positioning algorithms and aims to offer a compact overview of the wireless localization issues, concentrating on some of the major challenges and solutions in GNSS and RSS-based positioning. The GNSS-related challenges addressed here refer to the channel modelling part for indoor GNSS and to the acquisition part in High Sensitivity (HS)-GNSS. The RSSrelated challenges addressed here refer to the data collection and calibration, channel effects such as path loss and shadowing, and three-dimensional indoor positioning estimation.This thesis presents a measurement-based analysis of indoor channel models for GNSS signals and of path loss and shadowing models for WLAN and cellular signals. Novel low-complexity acquisition algorithms are developed for HS-GNSS. In addition, a solution to transmitter topology evaluation and database reduction solutions for large-scale mobile-centric RSS-based positioning are proposed. This thesis also studies the effect of RSS offsets in the calibration phase and various floor estimators, and offers an extensive comparison of different RSS-based positioning algorithms