The purpose of the thesis is to design and physically implement a system for location of devices in a Wi-Fi based networks deployed in the interior of small and medium-sized enterprises. First of all, the attention is given to the survey of commonly available technologies suitable for determination of the object position. Then, based on these findings, architecture of a location system comprising an array of sensor nodes and central processing unit is proposed. In conclusion, the results are presented and the fulfillment of the requirements is evaluated.

In this paper, we introduce a clean-slate architecture for improving the delivery of data packets in IEEE 802.11 wireless mesh networks. Opposed to the rigid TCP/IP layer architecture which exhibits serious deficiencies in such networks, we propose a unitary layer approach that combines both routing and transport functionalities in a single layer. The new Mesh Transmission Layer (MTL) incorporates cross-interacting routing and transport modules for a reliable data delivery based on the loss probabilities of wireless links. Due to the significant drawbacks of standard TCP over IEEE 802.11, we particularly focus on the transport module, proposing a pure rate-based approach for transmitting data packets according to the current contention in the network. By considering the IEEE 802.11 spatial reuse constraint and employing a novel acknowledgment scheme, the new transport module improves both goodput and fairness in wireless mesh networks. In a comparative performance study, we show that MTL achieves up to 48% more goodput and up to 100% less packet drops than TCP/IP, while maintaining excellent fairness results.

There are several applications that use sensor motes and researchers continue to explore additional applications. For this particular application of detecting the movement of humans through the sensor field, a set of Berkley mica2 motes on TinyOS operating system is used. Different sensors such as pressure, light, and so on can be used to identify the presence of an intruder in the field. In our case, the light sensor is chosen for the detection. When an intruder crosses the monitored environment, the system detects the changes of the light values, and any significant change meaning that a change greater than a pre-defined threshold. This indicates the presence of an intruder. An integrated web cam is used to take snapshot of the intruder and transmit the picture through the network to a remote station. The basic motivation of this thesis is that a sensor web system can be used to monitor and detect any intruder in a specific area from a remote location.

No description available.

As a license-exempt technology, Ultra Wideband (UWB) can be used for numerous commercial and military applications, including ranging, sensing, low-range networking and multimedia consumer products. In the networking and consumer fields, the technology is envisioned to reach the mass market, with a very high density of UWB devices per home and office. The technology is based on the concept of transmitting a signal with very low power spectral density (PSD), while occupying a very wide bandwidth. In principle, the low emissions mask protects incumbent systems operating in the same spectrum from being interfered with, while the wide bandwidth offers the possibility of high data rates, in excess of 250 Mbps. UWB has been regulated to operate in the 3.1 to 10.6 GHz portion of the spectrum, with an emissions mask for the lower and upper bands outside this range. The commercial wireless mobile services based on third generation (3G) networks occupy a portion of the spectrum in the 2 GHz band, falling under the UWB emissions mask. UWB and UMTS (Universal Mobile Telephone Systems) devices will coexist, sharing the same spectrum. In this research, we investigate the UWB-3G coexistence problem, analyzing the impact of UWB on UMTS networks. Firstly, we review the mathematical model of the UWB signal, its temporal and spectral properties. We then analyze and model the effects of the UWB signal on a narrowband receiver. Next, we characterize the response of the UMTS receiver to UWB interference, determining its statistical behavior, and establishing a model to replicate it. We continue by proposing a link level model that offers a first order quantitative estimate of the impact of a UWB interferer on a UMTS victim receiver, demonstrating the potentially harmful effect of UWB on the UMTS link. We elaborate on that initial evidence by proposing and implementing a practical systemlevel algorithm to realistically simulate the behavior of the UMTS network in the presence of multiple sources of UWB interference. We complete the research by performing UMTS system level simulations under various conditions of UWB interference, with the purpose of assessing its impact upon a typical UMTS network. We analyze the sensitivity of the main UWB parameters affecting UMTS performance, investigating the coverage and capacity performance aspects of the network. The proposed analysis methodology creates a framework to characterize the impact that mass-deployed UWB can have on the performance of a 3G system. The literature on UWB-3G coexistence is inconclusive, and even contradictory, as to the impact UWB can have on the performance of third-generation wireless networks. While some studies show that UWB can be highly detrimental to 3G networks, others have concluded that both systems can gracefully coexist. Through this study, we found that at the current emissions limits regulated for UWB, a mass uptake of this technology can negatively affect the performance of third-generation (3G) wireless networks. The quality of service experienced by a 3G user in close proximity to an active UWB device can be noticeably degraded, in the form of reduced coverage range, poor voice quality (for a voice call), lower data rates (for a data session) or, in a extreme situation, complete service blockage. As the ratio of UWB devices surrounding a 3G user grows, the degradation becomes increasingly more evident. We determined that in order for UWB tocoexist with 3G networks without causing any performance degradation, a minimum power backoff of 20 dB should be applied to the current emission limits. / Ph. D.

Over the last two decades, wireless technology has become ubiquitous in the United States and other developed countries. Consumer devices such as AM/FM radios, cordless and cellular telephones, pagers, satellite televisions, garage door openers, and television channel changers are just some of the applications of wireless technology. More recently, wireless computer networking has seen increasing employment. A few reasons for this move toward wireless networking are improved electronics transmitters and receivers, reduced costs, simplified installation, and enhanced network expandability. The objective of the study is to generate understanding of the planning inherent in a broadband, fixed wireless telecommunication network and to implement that knowledge into an SDSS. Intermediate steps toward this goal include solutions to both fixed wireless point-to-multipoint (PMP) and fixed wireless mesh networks, which are developed and incorporated into the SDSS. This study explores the use of a Spatial Decision Support System (SDSS) for broadband fixed wireless connectivity to solve the wireless network planning problem. The spatial component of the DSS is a Geographic Information System (GIS), which displays visibility for specific tower locations. The SDSS proposed here incorporates cost, revenue, and performance capabilities of a wireless technology applied to a given area. It encompasses cost and range capabilities of wireless equipment, the customers' propensity to pay, the market penetration of a given service offering, the topology of the area in which the wireless service is proffered, and signal obstructions due to local geography. This research is both quantitative and qualitative in nature. Quantitatively, the wireless network planning problem may be formulated as integer programming problems (IP). The line-of-sight restriction imposed by several extant wireless technologies necessitates the incorporation of a GIS and the development of an SDSS to facilitate the symbiosis of the mathematics and geography. The qualitative aspect of this research involves the consideration of planning guidelines for the general wireless planning problem. Methodologically, this requires a synthesis of the literature and insights gathered from using the SDSS above in a what-if mode. / Ph. D.

Mobile Ad hoc Network (MANET) routing protocols are designed to provide connectivity between wireless mobile nodes that do not have access to high-speed backbone networks. While many unicast MANET protocols have been explored, research involving multicast protocols has been limited. Existing multicast algorithms attempt to reduce routing overhead, but few, if any, attempt to reduce data overhead. The broadcast nature of wireless communication creates a unique environment in which overlaps in coverage are common. When designed properly, a multicast algorithm can take advantage of these overlaps and reduce data overhead. Unlike a unicast route, in which there is one path between a sender and receiver, a multicast tree can have multiple branches between the sender and its multiple receivers. Some of these paths can be combined to reduce redundant data rebroadcasts. The extensions presented in this thesis are a combination of existing and original routing techniques that were designed to reduce data rebroadcasts by aggregating multicast data flows. One such optimization takes advantage of the multipoint relay (MPR) nodes used by the Optimized Link State Routing (OLSR) unicast protocol. These nodes are used in unicast routing to reduce network broadcast, but can be used to help create efficient multicast data flows. Additionally, by listening to routing messages meant for other nodes, a host can learn a bit about its network and may be able to make routing changes that improve the multicast tree. This protocol was implemented as a software router in Linux. It should be emphasized that this is a real implementation and not a simulation. Experiments showed that the number of data packets in the network could be reduced by as much as 19 percent. These improvements were accomplished while using only a small amount of routing overhead. / Master of Science

No description available.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / A previous paper was presented detailing the design and testing of the first networked demonstration system (ITC 2006) for iNET. This paper extends that work by testing a commercial off the shelf (COTS) solution for the wireless network connection of the Telemetry Network System (TmNS). This paper will briefly discuss specific pieces of the airborne and ground station system but will concentrate on the new wireless network link, how it was tested, and how well it performed. Flight testing results will be presented accessing the performance of the wireless network link.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / An rfNET solution based on IEEE 802.11 wireless network is presented to perform one-way remote transmission of airborne instrumentation data and multi-channel video images in flight test by modifying the wireless network bridge and UDP protocol. Its architecture and structure is introduced briefly and the results of ground transmission test and flight demonstration transmission are provided. It also points out the major problems of this solution for engineering application and their solutions.