International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Wireless interfaces are becoming ubiquitous in terrestrial applications ranging from local area networking in business and commercial environments to large scale factory automation and process control. The pressure to develop these wireless interfacing techniques has come from the need to reduce cabling, reduce installation costs, and make it easier to extend network infrastructures. Concerns about electromagnetic compatibility, safety, reliability, and security have lead to the development of techniques and protocols that enable such wireless interfaces to be operated in electromagnetically harsh environments, without generating unacceptable interference, and providing reliable, dependable and secure data communications. On the face of it, the use of wireless interfaces onboard spacecraft looks like a good way of reducing the spacecraft harness mass and bulk. However, recent work by the European Space Agency has shown that, while harness reduction will undoubtedly be one benefit of using wireless interfaces, they offer many other benefits that will be more significant in the near future. Amongst these are significant advantages during integration and testing, the ability to retrofit and upgrade facilities, and cable replacement in moving structures such as robotic arms. In this paper we briefly survey the benefits of wireless interface technologies for spacecraft onboard use, and identify the challenges involved in adapting them for flight use. We then look at the considerations that should be taken into account in establishing the financial case for developing wireless interface technologies for flight applications.

This thesis presents the design and validation of a wireless interface for a vulvar quantitative sensory testing device (v-QueST). The wireless interface works in tandem with an Android application which allows a patient to indicate when their pressure pain threshold has been reached via an on-screen button. Using the fully assembled prototype, the sampling frequency and response time of the wireless interface was validated. The results indicated that the sampling frequency was sufficient to meet the desired specifications, and the time delay between the tap of the on-screen button and the reading of the force measurement was negligible. However, inspection of the force time-series acquired from the v-QueST device through Bluetooth transmission revealed systematic error. Implementation of a new signal conditioner is recommended before using the v-QueST device for research or clinical applications to objectively measure vulvar pain sensitivity.

RF fingerprinting can solve the indoor positioning problem with satisfactory accuracy, but the methodology depends on the so-called radio map calibrated in the offline phase via manual site-survey, which is costly, time-consuming and somewhat error-prone. It also assumes the RF fingerprint’s signal-spatial correlations to remain static throughout the online positioning phase, which generally does not hold in practice. This is because indoor environments constantly experience dynamic changes, causing the radio signal strengths to fluctuate over time, which weakens the signal-spatial correlations of the RF fingerprints. State-of-the-arts have proposed adaptive RF fingerprint methodology capable of calibrating the radio map in real-time and on-demand to address these drawbacks. However, existing implementations are highly server-centric, which is less robust, does not scale well, and not privacy-friendly. This thesis aims to address these drawbacks by exploring the feasibility of implementing an adaptive RF fingerprint indoor positioning system in a distributed and client-centric architecture using only commodity Wi-Fi hardware, so it can seamlessly integrate with existing Wi-Fi network and allow it to offer both networking and positioning services. Such approach has not been explored in previous works, which forms the basis of this thesis’ main contribution. The proposed methodology utilizes a network of distributed location beacons as its reference infrastructure; hence the system is more robust since it does not have any single point-of-failure. Each location beacon periodically broadcasts its coordinate to announce its presence in the area, plus coefficients that model its real-time RSS distribution around the transmitting antenna. These coefficients are constantly self-calibrated by the location beacon using empirical RSS measurements obtained from neighbouring location beacons in a collaborative fashion, and fitting the values using path loss with log-normal shadowing model as a function of inter-beacon distances while minimizing the error in a least-squared sense. By self-modelling its RSS distribution in real-time, the location beacon becomes aware of its dynamically fluctuating signal levels caused by physical, environmental and temporal characteristics of the indoor environment. The implementation of this self-modelling feature on commodity Wi-Fi hardware is another original contribution of this thesis. Location discovery is managed locally by the clients, which means the proposed system can support unlimited number of client devices simultaneously while also protect user’s privacy because no information is shared with external parties. It starts by listening for beacon frames broadcasted by nearby location beacons and measuring their RSS values to establish the RF fingerprint of the unknown point. Next, it simulates the reference RF fingerprints of predetermined points inside the target area, effectively calibrating the site’s radio map, by computing the RSS values of all detected location beacons using their respective coordinates and path loss coefficients embedded inside the received beacon frames. Note that the coefficients model the real-time RSS distribution of each location beacon around its transmitting antenna; hence, the radio map is able to adapt itself to the dynamic fluctuations of the radio signal to maintain its signal-spatial correlations. The final step is to search the radio map to find the reference RF fingerprint that most closely resembles the unknown sample, where its coordinate is returned as the location result. One positioning approach would be to first construct a full radio map by computing the RSS of all detected location beacons at all predetermined calibration points, then followed by an exhaustive search over all reference RF fingerprints to find the best match. Generally, RF fingerprint algorithm performs better with higher number of calibration points per unit area since more locations can be classified, while extra RSS components can help to better distinguish between nearby calibration points. However, to calibrate and search many RF fingerprints will incur substantial computing costs, which is unsuitable for power and resource limited client devices. To address this challenge, this thesis introduces a novel algorithm suitable for client-centric positioning as another contribution. Given an unknown RF fingerprint to solve for location, the proposed algorithm first sorts the RSS in descending order. It then iterates over this list, first selecting the location beacon with the strongest RSS because this implies the unknown location is closest to the said location beacon. Next, it computes the beacon’s RSS using its path loss coefficients and coordinate information one calibration point at a time while simultaneously compares the result with the measured value. If they are similar, the algorithm keeps this location for subsequent processing; else it is removed because distant points relative to the unknown location would exhibit vastly different RSS values due to the different site-specific obstructions encountered by the radio signal propagation. The algorithm repeats the process by selecting the next strongest location beacon, but this time it only computes its RSS for those points identified in the previous iteration. After the last iteration completes, the average coordinate of remaining calibration points is returned as the location result. Matlab simulation shows the proposed algorithm only takes about half of the time to produce a location estimate with similar positioning accuracy compared to conventional algorithm that does a full radio map calibration and exhaustive RF fingerprint search. As part of the thesis’ contribution, a prototype of the proposed indoor positioning system is developed using only commodity Wi-Fi hardware and open-source software to evaluate its usability in real-world settings and to demonstrate possible implementation on existing Wi-Fi installations. Experimental results verify the proposed system yields consistent positioning accuracy, even in highly dynamic indoor environments and changing location beacon topologies.

Master’s thesis deals with the design and realization of a hotspot system for more Operators, it solves problems of QoS, billing of transferred data and distribution of services via a common wireless interface. The theoretic part is oriented to the selection of a suitable technology and explanation of a legislation, which relates to an activity of the hotspot‘s network. The practical part solves the choice of hardware, design and realization of the experimental network. In conclusion are tested transit parameters of the network and its functionality.

The thesis aim is in practical realization of wireless interface, which is created by infrared relay in motorcycle Simson. Infrared relay is used for speed measuring. This work describes the realization of digital controlling by microcontrollers. Digital controlling can easily improve and upgrade functions for better driving comfort. It’s possible by getting information about condition of selected motorcycle parts. This information can be engine temperature, battery charge, total distance and etc.

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Recent rapid advancements in mobile communication and emerging demands for complicated multimedia content and services over mobile systems have caused a dramatic increase in research interest in this area. Among the topics covering multimedia service performance over the wireless interface, the quality of received multimedia content is an important issue. With the increase of visual media in mobile services, user opinion acquired through perception of received image quality will play an increasingly important role in determining the effectiveness of such services. The work documented in this thesis is motivated by the general lack of published work on software test beds for Third Generation Mobile Network (3G) and in particular for investigating mobile environment multimedia quality degradation. A 3G multimedia quality analysis system is presented, subjecting the input multimedia stream to the simulated 3G radio activities and measuring its degradation in terms of human perception. This approach takes a new and different model of multimedia quality measurement in a wireless communication domain, showing the possibility of a more effective approach that can be applied in many cases for assisting service quality assurance research across this area. The development of this software system is covered in detail together with in-depth analysis of multimedia image quality over a simulated 3G radio interface. Universal Mobile Telecommunications System (UMTS) is the 3G standard chosen for study in this work. The suggested test bed simulates a single Frequency Division Duplex (FDD) downlink UMTS Territorial Radio Access (UTRA) channel, where the received media's image analysis is performed using a Human Vision System (HVS) based image quality metric. The system aims to provide a multipurpose and versatile multimedia 3G test bed for use in testing of various solutions for protecting multimedia data across a 3G radio interface. Furthermore, it produces effective human vision oriented feedback on visual media degradation, providing a new and efficient method to address effectiveness of solutions in multimedia delivery over a mobile environment. This thesis shows the ability of HVS-based image quality metric in analyzing degradation of visual media over a noisy mobile environment. This presents a novel direction in the area of telecommunication service multimedia quality analysis, with potential user quality perception being considered on top of data or signal-based error measurements. With such a new approach, development of multimedia protection solutions can be made more effective. Effective feedback provided by considering quality measurement with strong correlation to human perception allows close analysis of user visual discrimination across an image. An example of the usefulness of this information is especially visible if considering development of a content-based multimedia data protective system that provides different levels of protection, depending on the importance of visual media. An apparent potential application of this thesis is in the testing of a multimedia/image protection protocol in a downlink channel. Future work might aim to extend the current system by adding network level traffic simulations and further addition of dynamic network control components, further considering network traffic conditions.