Software defined wireless network (sdwn) for industrial environment: case of underground mine

Avec le développement continu des industries minières canadiennes, l’établissement des réseaux de communications souterrains avancés et sans fil est devenu un élément essentiel du processus industriel minier et ceci pour améliorer la productivité et assurer la communication entre les mineurs. Cette étude vise à proposer un système de communication minier en procurant une architecture SDWN (Software Defined Wireless Network) basée sur la technologie de communication LTE. Dans cette étude, les plateformes les plus importantes de réseau mobile 4G ont été étudiées, configurées et testées dans deux zones différentes : un tunnel de mine souterrain et un couloir intérieur étroit. Également, une architecture mobile combinant SDWN et NFV (Network Functions Virtualization) a été réalisée

Low-Cost GNSS Simulators with Wireless Clock Synchronization for Indoor Positioning

In regions where global navigation satellite systems (GNSS) signals are unavailable, such as underground areas and tunnels, GNSS simulators can be deployed for transmitting simulated GNSS signals. Then, a GNSS receiver in the simulator coverage outputs the position based on the received GNSS signals (e.g., Global Positioning System (GPS) L1 signals in this study) transmitted by the corresponding simulator. This approach provides periodic position updates to GNSS users while deploying a small number of simulators without modifying the hardware and software of user receivers. However, the simulator clock should be synchronized to the GNSS satellite clock to generate almost identical signals to the live-sky GNSS signals, which is necessary for seamless indoor and outdoor positioning handover. The conventional clock synchronization method based on the wired connection between each simulator and an outdoor GNSS antenna causes practical difficulty and increases the cost of deploying the simulators. This study proposes a wireless clock synchronization method based on a private time server and time delay calibration. Additionally, we derived the constraints for determining the optimal simulator coverage and separation between adjacent simulators. The positioning performance of the proposed GPS simulator-based indoor positioning system was demonstrated in the underground testbed for a driving vehicle with a GPS receiver and a pedestrian with a smartphone. The average position errors were 3.7 m for the vehicle and 9.6 m for the pedestrian during the field tests with successful indoor and outdoor positioning handovers. Since those errors are within the coverage of each deployed simulator, it is confirmed that the proposed system with wireless clock synchronization can effectively provide periodic position updates to users where live-sky GNSS signals are unavailable.Comment: Submitted to IEEE Acces

Применение программно-определяемого радио в системах связи

The paper presents examples of solving urgent telecommunication tasks using the technology of Software-defined radio systems (SDR). The problem and the role of SDR in its solution are described for each example. The comparison of the main characteristics and structure of the hardware components of the SDR, which are used in the considered examples, is given. The results of the work with the debugging module for the Russian microchip 1288HK1T according to the scenario of the demo version of functioning are presented. Kuvshinov O. A., Plokhikh O. V. Application of Software-defined radio in communication systems. Ural Radio Engineering Journal. 2022;6(2):140–159. (In Russ.) DOI: 10.15826/urej.2022.6.2.002.В работе представлены примеры решения актуальных задач электросвязи с использованием технологии программно-определяемых радиосистем (ПОР). Для каждого примера описана проблема и роль ПОР в ее решении. Приведено сравнение основных характеристик и структуры аппаратных составляющих ПОР, которые используются в рассмотренных примерах. Представлены результаты работы с отладочным модулем для российской микросхемы ПОР 1288ХК1Т по сценарию демонстрационного варианта функционирования. Кувшинов О. А., Плохих О. В. Применение программно-определяемого радио в системах связи. Ural Radio Engineering Journal. 2022;6(2):140–159. DOI: 10.15826/urej.2022.6.2.002.

Teaching Your Wireless Card New Tricks: Smartphone Performance and Security Enhancements Through Wi-Fi Firmware Modifications

Smartphones come with a variety of sensors and communication interfaces, which make them perfect candidates for mobile communication testbeds. Nevertheless, proprietary firmwares hinder us from accessing the full capabilities of the underlying hardware platform which impedes innovation. Focusing on FullMAC Wi-Fi chips, we present Nexmon, a C-based firmware modification framework. It gives access to raw Wi-Fi frames and advanced capabilities that we found by reverse engineering chips and their firmware. As firmware modifications pose security risks, we discuss how to secure firmware handling without impeding experimentation on Wi-Fi chips. To present and evaluate our findings in the field, we developed the following applications. We start by presenting a ping-offloading application that handles ping requests in the firmware instead of the operating system. It significantly reduces energy consumption and processing delays. Then, we present a software-defined wireless networking application that enhances scalable video streaming by setting flow-based requirements on physical-layer parameters. As security application, we present a reactive Wi-Fi jammer that analyses incoming frames during reception and transmits arbitrary jamming waveforms by operating Wi-Fi chips as software-defined radios (SDRs). We further introduce an acknowledging jammer to ensure the flow of non-targeted frames and an adaptive power-control jammer to adjust transmission powers based on measured jamming successes. Additionally, we discovered how to extract channel state information (CSI) on a per-frame basis. Using both SDR and CSI-extraction capabilities, we present a physical-layer covert channel. It hides covert symbols in phase changes of selected OFDM subcarriers. Those manipulations can be extracted from CSI measurements at a receiver. To ease the analysis of firmware binaries, we created a debugging application that supports single stepping and runs as firmware patch on the Wi-Fi chip. We published the source code of our framework and our applications to ensure reproducibility of our results and to enable other researchers to extend our work. Our framework and the applications emphasize the need for freely modifiable firmware and detailed hardware documentation to create novel and exciting applications on commercial off-the-shelf devices

Doctor of Philosophy

dissertationThe continuous growth of wireless communication use has largely exhausted the limited spectrum available. Methods to improve spectral efficiency are in high demand and will continue to be for the foreseeable future. Several technologies have the potential to make large improvements to spectral efficiency and the total capacity of networks including massive multiple-input multiple-output (MIMO), cognitive radio, and spatial-multiplexing MIMO. Of these, spatial-multiplexing MIMO has the largest near-term potential as it has already been adopted in the WiFi, WiMAX, and LTE standards. Although transmitting independent MIMO streams is cheap and easy, with a mere linear increase in cost with streams, receiving MIMO is difficult since the optimal methods have exponentially increasing cost and power consumption. Suboptimal MIMO detectors such as K-Best have a drastically reduced complexity compared to optimal methods but still have an undesirable exponentially increasing cost with data-rate. The Markov Chain Monte Carlo (MCMC) detector has been proposed as a near-optimal method with polynomial cost, but it has a history of unusual performance issues which have hindered its adoption. In this dissertation, we introduce a revised derivation of the bitwise MCMC MIMO detector. The new approach resolves the previously reported high SNR stalling problem of MCMC without the need for hybridization with another detector method or adding heuristic temperature scaling terms. Another common problem with MCMC algorithms is an unknown convergence time making predictable fixed-length implementations problematic. When an insufficient number of iterations is used on a slowly converging example, the output LLRs can be unstable and overconfident, therefore, we develop a method to identify rare, slowly converging runs and mitigate their degrading effects on the soft-output information. This improves forward-error-correcting code performance and removes a symptomatic error floor in bit-error-rates. Next, pseudo-convergence is identified with a novel way to visualize the internal behavior of the Gibbs sampler. An effective and efficient pseudo-convergence detection and escape strategy is suggested. Finally, the new excited MCMC (X-MCMC) detector is shown to have near maximum-a-posteriori (MAP) performance even with challenging, realistic, highly-correlated channels at the maximum MIMO sizes and modulation rates supported by the 802.11ac WiFi specification, 8x8 256 QAM. Further, the new excited MCMC (X-MCMC) detector is demonstrated on an 8-antenna MIMO testbed with the 802.11ac WiFi protocol, confirming its high performance. Finally, a VLSI implementation of the X-MCMC detector is presented which retains the near-optimal performance of the floating-point algorithm while having one of the lowest complexities found in the near-optimal MIMO detector literature