Opportunistic Access in Frequency Hopping Cognitive Radio Networks

Researchers in the area of cognitive radio often investigate the utility of dynamic spectrum access as a means to make more efficient use of the radio frequency spectrum. Many studies have been conducted to find ways in which a secondary user can occupy spectrum licensed to a primary user in a manner which does not disrupt the primary user\u27s performance. This research investigates the use of opportunistic access in a frequency hopping radio to mitigate the interference caused by other transmitters in a contentious environment such as the unlicensed 2.4 GHz region. Additionally, this work demonstrates how dynamic spectrum access techniques can be used not only to prevent interfering with other users but also improve the robustness of a communication system

Wireless security for secure facilities

This thesis presents methods for securing a facility that has wireless connectivity. The goal of this research is to develop a solution to securing a facility that utilizes wireless communications. The research will introduce methods to track and locate the position of attackers. This research also introduces the idea of using a Honeynet system for added security. This research uses what is called Defense-In-Depth. Defense-in-depth is when multiple layers of security are used. The first of the layers is the Zone of Interference. This Zone is an area where jammer transmitters and directive antennas are set up to take advantage of the near-far-effect. The idea is to use the near-far-effect to give a stronger signal on the perimeter of the secure area, to mask any signals escaping from the secure area. This Zone uses directive Yagi antenna arrays to direct the radiation. There are multiple jamming methods that are utilized within this Zone. The next layer of security is the Honeynet Zone. The idea is to make an attacker believe that they are seeing real network traffic. This is done at the Honeynet Zone once a device has been determined to be unfriendly. Decoy mobile devices are first placed within the Honeynet Zone. Spoofed traffic is then created between the Honeynet base stations and the decoy mobile devices zone; using adaptive antennas incorporated within the design to face the signals away from the inside secure area. The third defense is position location and tracking. The idea is to have constant tracking of all devices in the area. There are several methods available to locate and track a device that is giving off an RF signal. This thesis looks at combining all these methods into an integrated, and more robust, facility security system

77-GHz Waveform Generator with Multiple Frequency Shift Keying for Multi-target Detection Automotive Radar Applications

Department of Electrical EngineeringIn automotive radar applications, the modulation waveform plays an important role in detecting multiple targets. Two well-known continuous waves in the literature are Frequency Modulated Continuous Wave (FMCW) and Frequency Shift Keying (FSK). These two waveforms basically ful l the requirements of automotive radars. However, two modulations have limitations in multiple target situations. The ghost targets are introduced in FMCW radars, thus two or more measurement cycles are expanded to resolve the target ambiguities. In contrast to that FSK cannot solve targets in range direction. For this reason, the combination of FMCW and FSK was proposed, called MFSK. This waveform shows good performance, with a high range and velocity resolution, short measurement time, and ability to avoid ghost targets. The main drawback of this modulation is the complexity. In this thesis, all the perspectives about MFSK modulation waveform from basic fundamentals to hardware implementation are presented. In addition, the proposed MFSK waveform generator for automotive radar system is elaborated to improve the target detections and shorter measurement time.. . .ope

SIMULINK Implementation of a CDMA Transmitter

An implementation of a Code Division Multiple Access (CDMA) transmitter has been developed using SIMULINK and MATLAB. This transmitter uses a modified carrier in modulation. This modified carrier, which is frequency modulated, has been shown to reduce intersymbol interference (ISI) and multiple access interference (MAl). These two types of interference are caused by multipath propagation which results in delayed versions of the original signal. The benefits of this modified modulation technique are apparent when there are delays involved. The spreading sequences used are 7- bit Gold codes which allow a maximum of nine users. The initial trials of the transmitter indicate that it is functioning correctly

A Comprehensive Review of Unmanned Aerial Vehicle Attacks and Neutralization Techniques

Unmanned Aerial Vehicles (UAV) have revolutionized the aircraft industry in this decade. UAVs are now capable of carrying out remote sensing, remote monitoring, courier delivery, and a lot more. A lot of research is happening on making UAVs more robust using energy harvesting techniques to have a better battery lifetime, network performance and to secure against attackers. UAV networks are many times used for unmanned missions. There have been many attacks on civilian, military, and industrial targets that were carried out using remotely controlled or automated UAVs. This continued misuse has led to research in preventing unauthorized UAVs from causing damage to life and property. In this paper, we present a literature review of UAVs, UAV attacks, and their prevention using anti-UAV techniques. We first discuss the different types of UAVs, the regulatory laws for UAV activities, their use cases, recreational, and military UAV incidents. After understanding their operation, various techniques for monitoring and preventing UAV attacks are described along with case studies

Methods of Improving Wireless Communication in Home Automation and Security

Tato práce představuje možnosti vylepšení bezdrátové komunikace pro systémy domácí automatizace a zabezpečení. Většina dnešních systémů používá jednofrekvenční komunikaci. Přidání frekvenčního skákání zvyšuje odolnost proti rušení, ale přináší problémy s výdrží baterie nebo s rychlostí odezvy, které nejsou v této třídě elektroniky jednoduše řešitelné.První metoda představená v této práci je vícekanálový přijímač pro centrální jednotku. To umožňuje senzorům spát a po probuzení neřešit synchronizaci se sítí.Druhá metoda je kombinace vícekanálového přijímače s komunikací bezdrátových kamer. Komunikace senzorů se skryje do přenosu obrazu bez přidání dalšího rádia.This thesis presents methods of improving wireless communication in home automation and security. Most current systems use single-frequency communication. Frequency hopping improves resistivity to interference but brings problems with battery lifespan or communication delay, which cannot be simply solved in this class of electronics.The first method proposed in this work is an all-channel receiver for the central unit. It allows the sensors to sleep and avoid lengthy network synchronization after wakeup.The second method is a combination of the all-channel receiver with a communication of wireless cameras. The sensor communication is hidden in video transfer without additional hardware.

Application of advanced on-board processing concepts to future satellite communications systems: Bibliography

Abstracts are presented of a literature survey of reports concerning the application of signal processing concepts. Approximately 300 references are included