ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / Spread Spectrum (SS) techniques are methods used to deliberately spread the spectrum of transmitted signals in communication systems. The increased bandwidth makes detection of these signals challenging for non-cooperative receivers. In this paper, we investigate detection of Frequency Hopping Spread Spectrum (FHSS) signals from compressive measurements. The theoretical and simulated performances of the proposed methods are compared to those of the conventional methods.

Frequency Hopping Spread Spectrum (FHSS) signaling is used across many devices operating in both regulated and unregulated bands. In either situation, if there is a malicious device operating within these bands, or more simply a user operating out of the required specifications, the identification this user important to insure communication link integrity and interference mitigation. The identification of a user involves the grouping of that users signal transmissions, and the separation of those transmission from transmissions of other users in a shared frequency band. Traditional signal separation methods often require difficult to obtain hardware fingerprinting characteristics or approximate geo-location estimates. This work will consider the characteristics of FHSS signals that can be extracted directly from signal detection. From estimates of these hopping characteristics, novel source separation with classic clustering algorithms can be performed. Background knowledge derived from the time domain representation of received waveforms can improve these clustering methods with the novel application of cannot-link pairwise constraints to signal separation. For equivalent clustering accuracy, constraint-based clustering tolerates higher parameter estimation error, caused by diminishing received signal-to-noise ratio (SNR), for example. Additionally, prior work does not fully cover the implications of detecting and estimating FHSS signals using image segmentation on a Time-Frequency (TF) waterfall. This work will compare several methods of FHSS signal detection, and discuss how each method may effect estimation accuracy and signal separation quality. The use of constraint-based clustering is shown to provide higher clustering accuracy, resulting in more reliable separation and identification of active users in comparison to traditional clustering methods. / Master of Science / The expansion of technology in areas such as smart homes and appliances, personal devices, smart vehicles, and many others, leads to more and more devices using common wireless communication techniques such as WiFi and Bluetooth. While the number of wirelessly connected users expands, the range of frequencies that support wireless communications does not. It is therefore essential that each of these devices unselfishly share the available wireless resources. If a device is using more resources than the required limits, or causing interference with other’s communications, this device will impact many others negatively and therefore preventative action must be taken to prevent further disruption in the wireless environment. Before action can be taken however, the device must first be identified in a mixture of other wireless activity. To identify a specific device, first, a wireless receiver must be in close enough proximity to detect the power that the malicious device is emitting through its wireless communication. This thesis provides a method that can be used to identify a problem user based only off of its wireless transmission behavior. The performance of this identification is shown with respect to the received signal power which represents the necessary range that a listening device must be to identify and separate a problem user from other cooperative users that are communicating wirelessly.

This document deals with the control software for professional Model-radio transmitter. The aim of the thesis is to design a functional solution that would satisfy the requirements of existing aircraft modelers (and others), thus to compete against other manufacturers of radio sets. In the following pages there is presented the design and implementation of user interface with regard to functionality and clarity, then the basic algorithms for driving aircraft models are explored. As a result of those findings the control software is implemented for an embedded device using the supplied hardware components.

Currently, wireless communication technologies are expected to be widely employed for in-vehicle communication where in-vehicle communication is built upon the interactions of different parts inside the vehicle. This communication is to enable a variety of applications for driver and passenger needs.  To have improved driving assistance, development of in-vehicle applications is very much needed. At present, intelligent systems inside the vehicle are mostly dominated by the wired technologies. The possibilities of wireless communication have inspired us and made an opportunity to analyse replacements for wired communication within a vehicle. In this connection, the scope of our thesis is to define the in-vehicle applications which are preferred by the wireless technologies, to define the applications using wired technologies which could be replaced by the wireless technologies and to identify those applications which are difficult to implement by the wireless technologies.   In-vehicle wired networks; and problems of these wired networks, along with several existing applications, have been discussed at the initial stage of this thesis for the purpose of having a clear understanding. After that, existing In-vehicle wireless applications and several challenging applications have also been studied. Studies have been done on the most important wireless technologies with their respective specifications. The requirement of establishing wireless communication has also been explained. Finally, an analysis has been done according to the requirements of the applications and verification of their possible reliance on the wireless technologies.   In a brief, comparable studies have been done among the wireless technologies to assess their current and future fitness for In-vehicle applications. The thesis concludes with some recommendations regarding when wireless technologies might be suitable for some in-vehicle applications to replace the wired technologies.

<p>This thesis work started with an extensive literature study in several areas, ZigBee, instruments and measuring methods. The knowledge was implemented in use with the ZigBee modules from the two manufacturers ITN and Chipcon along with ZigBee Software Stack. Measuring methods were developed and software in ZigBee software Stack was developed to use in the ZigBee modules for the measurements. Developing measurement methods and performing measurements was an iterative process for the different measurements. The aim was to characterize the ZigBee modules in the most important areas during the extent of this master thesis work.</p>

This thesis work started with an extensive literature study in several areas, ZigBee, instruments and measuring methods. The knowledge was implemented in use with the ZigBee modules from the two manufacturers ITN and Chipcon along with ZigBee Software Stack. Measuring methods were developed and software in ZigBee software Stack was developed to use in the ZigBee modules for the measurements. Developing measurement methods and performing measurements was an iterative process for the different measurements. The aim was to characterize the ZigBee modules in the most important areas during the extent of this master thesis work.

This thesis is concerned the technology with technologies of transfer through wireless devices. It is about possibilities of optimization of transfer in wireless net, especially of the reduction of interference influence. The first part is about theory and the standards development of wireless technology. There are methods and principles used in wireless technologies. The second part is a practical measuring and testing of an internal wireless net, with the emphasis being on the source of interference influence. Measuring was focused on interference between access points and was not about meteorological influence. It continues with theory and testing of interference of the microwave oven in our wireless net. Then, it is a practical demonstration of interference in an external environment. There are practical examples of interference between different providers’ nets on the same area and solutions to prevent or to cancel this interference. In next part of work the wireless net is parsed and described in a given territory. Here is described the way how to precede the reciprocal interference and eventually how this mutual disturbance suppress. Consequently, our net is optimized for customer growth and for today’s options of newer and more powerful components for wireless transfer. Finally there are two laboratory tasks. The first one is about practical measuring and testing of wireless net’s parameters and the second one is about simulation of wireless networks in the Opnet program.