After more than two decades’ development, modern mobile cellular networks now have almost approached to the commercial level of fourth generation communication networks. For each of the mobile solutions, there are special attributes but also similarities compared to the other competitive solutions. We can also find relationships between the old generation solutions and the inheritors or innovations. During the communicating session using any kind of existing mobile handset, the handover procedure is a very important one that may effect connection quality and also the phone call continuity. Nowadays, the mobile cellular networks have a trend to interact with LAN networks. They will co-exist and work together to support higher data rate over a wider coverage. Seamless handover proposals like Unlicensed Mobile Access (UMA) can support the heterogeneous handover between Global System for Mobile Communications (GSM) and Wireless (Wi-Fi) Network. Several Media Independent Handover (MIH) proposals can handle the vertical handover in the hybrid mobile data network environment such like between wireless local area network (WLAN) and Universal Mobile Telecommunications System (UMTS) by different solutions.

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Even if 3rd and 4th generation wireless systems aim to achieve multimedia services at high speed, it is rather difficult to have full-fledged multimedia services due to insufficient capacity of the systems. There are many technical challenges placed on us in order to realize the real multimedia services. One of those challenges is how efficiently to allocate resources to traffic as the wireless systems evolve. The review of the literature shows that strategic manipulation of traffic can lead to an efficient use of resources in both wire-line and wireless networks. This aspect brings our attention to the role of link layer protocols, which is to orchestrate the transmission of packets in an efficient way using given resources. Therefore, the Media Access Control (MAC) layer plays a very important role in this context. In this research, we investigate technical challenges involving resource control and management in the design of MAC protocols based on the characteristics of traffic, and provide some strategies to solve those challenges. The first and foremost matter in wireless MAC protocol research is to choose the type of multiple access schemes. Each scheme has advantages and disadvantages. We choose Wireless Code Division Multiple Access/Time Division Duplexing (WCDMA/TDD) systems since they are known to be efficient for bursty traffic. Most existing MAC protocols developed for WCDMA/TDD systems are interested in the performance of a unidirectional link, in particular in the uplink, assuming that the number of slots for each link is fixed a priori. That ignores the dynamic aspect of TDD systems. We believe that adaptive dynamic slot allocation can bring further benefits in terms of efficient resource management. Meanwhile, this adaptive slot allocation issue has been dealt with from a completely different angle. Related research works are focused on the adaptive slot allocation to minimize inter-cell interference under multi-cell environments. We believe that these two issues need to be handled together in order to enhance the performance of MAC protocols, and thus embark upon a study on the adaptive dynamic slot allocation for the MAC protocol. This research starts from the examination of key factors that affect the adaptive allocation strategy. Through the review of the literature, we conclude that traffic characterization can be an essential component for this research to achieve efficient resource control and management. So we identify appropriate traffic characteristics and metrics. The volume and burstiness of traffic are chosen as the characteristics for our adaptive dynamic slot allocation. Based on this examination, we propose four major adaptive dynamic slot allocation strategies: (i) a strategy based on the estimation of burstiness of traffic, (ii) a strategy based on the estimation of volume and burstiness of traffic, (iii) a strategy based on the parameter estimation of a distribution of traffic, and (iv) a strategy based on the exploitation of physical layer information. The first method estimates the burstiness in both links and assigns the number of slots for each link according to a ratio of these two estimates. The second method estimates the burstiness and volume of traffic in both links and assigns the number of slots for each link according to a ratio of weighted volumes in each link, where the weights are driven by the estimated burstiness in each link. For the estimation of burstiness, we propose a new burstiness measure that is based on a ratio between peak and median volume of traffic. This burstiness measure requires the determination of an observation window, with which the median and the peak are measured. We propose a dynamic method for the selection of the observation window, making use of statistical characteristics of traffic: Autocorrelation Function (ACF) and Partial ACF (PACF). For the third method, we develop several estimators to estimate the parameters of a traffic distribution and suggest two new slot allocation methods based on the estimated parameters. The last method exploits physical layer information as another way of allocating slot to enhance the performance of the system. The performance of our proposed strategies is evaluated in various scenarios. Major simulations are categorized as: simulation on data traffic, simulation on combined voice and data traffic, simulation on real trace data. The performance of each strategy is evaluated in terms of throughput and packet drop ratio. In addition, we consider the frequency of slot changes to assess the performance in terms of control overhead. We expect that this research work will add to the state of the knowledge in the field of link-layer protocol research for WCDMA/TDD systems. / Ph. D.

This thesis investigates several issues in data and computation modeling for scientific problem solving environments (PSEs). A PSE is viewed as a software system that provides (i) a library of simulation components, (ii) experiment management, (iii) reasoning about simulations and data, and (iv) problem solving abstractions. Three specific ideas, in functionalities (ii)-(iv), form the contributions of this thesis. These include the EMDAG system for experiment management, the BSML markup language for data interchange, and the use of data mining for conducting non-trivial parameter studies. This work emphasizes data modeling and management, two important aspects that have been largely neglected in modern PSE research. All studies are performed in the context of S4W, a sophisticated PSE for wireless system design. / Master of Science

Jamming is an ongoing threat that plagues wireless communications in contested areas. Unfortunately, jamming complexity and sophistication will continue to increase over time. The traditional approach to addressing the jamming threat is to harden radios, such that they sacrifice communications performance for more advanced jamming protection. To provide an escape from this trend, we investigate the previously unexplored area of jammer exploitation. This dissertation develops the concept of antifragile communications, defined as the capability for a communications system to improve in performance due to a system stressor or harsh condition. Antifragility refers to systems that increase in capability, resilience, or robustness as a result of disorder (e.g., chaos, uncertainty, stress). An antifragile system is fundamentally different from one that is resilient (i.e., able to recover from failure) and robust (i.e., able to resist failure). We apply the concept of antifragility to wireless communications through several novel strategies that all involve exploiting a communications jammer. These strategies can provide an increase in throughput, efficiency, connectivity, or covertness, as a result of the jamming attack itself. Through analysis and simulation, we show that an antifragile gain is possible under a wide array of electronic warfare scenarios. Throughout this dissertation we provide guidelines for realizing these antifragile waveforms. Other major contributions of this dissertation include the development of a communications jamming taxonomy, feasibility study of reactive jamming in a SATCOM-type scenario, and a reinforcement learning-based reactive jamming mitigation strategy, for times when an antifragile approach is not practical. Most of the jammer exploitation strategies described in this dissertation fall under the category of jammer piggybacking, meaning the communications system turns the jammer into an unwitting relay. We study this jammer piggybacking approach under a variety of reactive jamming behaviors, with emphasis on the sense-and-transmit type. One piggybacking approach involves transmitting using a specialized FSK waveform, tailored to exploit a jammer that channelizes a block of spectrum and selectively jams active subchannels. To aid in analysis, we introduce a generalized model for reactive jamming, applicable to both repeater-based and sensing-based jamming behaviors. Despite being limited to electronic warfare scenarios, we hope that this work can pave the way for further research into antifragile communications. / Ph. D.

This dissertation presents system and circuit development of the low-power multi-gigabit CMOS demodulator using analog and mixed demodulation techniques. In addition, critical building blocks of the low-power analog quadrature front-ends are designed and implemented using 90 nm CMOS with a targeted compatibility to the traditional demodulator architecture. It exhibits an IF-to-baseband conversion gain of 25 dB with 1.8 GHz of baseband bandwidth and a dynamic range of 23 dB while consuming only 46 mW from a 1 V supply voltage. Several different demodulators using analog signal processor (ASP) are implemented: (1) an ultra-low power non-coherent ASK demodulator is measured to demodulate a maximum speed of 3 Gbps while consuming 32 mW from 1.8 V supply; (2) a mere addition of 7.5 mW to the aforementioned analog quadrature front-end enables a maximum speed of 2.5 Gbps non-coherent ASK demodulation with an improved minimum sensitivity of -38 dBm; (3) a robust coherent BPSK demodulator is shown to achieve a maximum speed of 3.5 Gbps based on the same analog quadrature front-end with only additional 7 mW. Furthermore, an innovative seamless handover mechanism between ASP and PLL is designed and implemented to improve the frequency acquisition time of the coherent BPSK demodulator. These demodulator designs have been proven to be feasible and are integrated in a 60 GHz wireless receiver. The system has been realized in a product prototype and used to stream HD video as well as transfer large multi-media files at multi-gigabit speed.

<p>Due to the rapid development of wireless communication and network technology, more and more wireless devices (e.g., Siemens, Lutron, etc.) are used in residential and commercial buildings. The wireless system has many advantages that traditional wired-based systems do not have, such as time-saving deployment and easy maintenance. However, the wireless system is also vulnerable to cyber-attacks since the data packets are transmitted by radio waves rather than by physical medium. The current cyber detection system (e.g., Intrusion detection system) monitors the data traffic to identify the anomalies in the network. However, it is unable to detect the attacks that tamper with the control logic or operating parameters, which results in the malfunction of the system. This thesis developed an integrated, cyber-security framework for cyber-attack detection in smart buildings.</p> <p>The objective of this research is to develop an integrated cyber-security framework for wireless-based smart building systems to protect buildings from the cyber-attacks. The wireless-based smart building systems are operated and controlled by either a two-position or continuous controlled approach. The efforts in this study have developed a cyber-security framework to deal with both two-position control and continuous control. For the two-position controlled smart buildings, the developed cyber-security framework integrates the data and models of both cyber and physical domains of building systems to detect faults, abnormal operations, and cyber attacks. The cyber-security framework developed for the continuous controlled system combines a data-driven model for detecting the faults of sensor measurements and a physical model based on engineering principle (e.g., laws of thermodynamics or control logic) to detect the anomaly of system operation.</p> <p>To develop the cyber-security frameworks, the testbeds corresponding to the two-position and continuous wireless systems were constructed for attack-oriented tests. A wireless-based lighting system for smart homes was used as the testbed for the study of the two-position control. It has a wireless occupancy sensor, an actuator for the light switch, and an open-source operating platform (OpenHAB) for system control and monitor. The platform of the wireless is the ZigBee. An indoor shading system at a living lab in new Herrick building at Purdue University was utilized as the testbed for the study of the continuous controlled system. The indoor shading system exploits the roller shades to block the excess daylighting to provide an acceptable illuminance condition for occupants. The shading system uses the wireless illuminance sensor, weather condition, and wire-based controller to automatically operate the shades for the acceptable illuminance. </p> <p>The study implemented designed cyber-attacks to validate the effectiveness of the developed frameworks. The final results show that the developed two models were able to detect the attacks effectively (95-100% attacks identified and isolated). The abnormal operations tested in two-position control system were identified when an abnormal state was triggered, or the modelled state and real state did not match in the finite state machine model developed. For continuous control, the abnormal operations were detected when there is a significant deviation between the modelled measurement and the actual measurement. The cybersecurity framework developed in the thesis demonstrates an effective approach for detecting system faults caused by attacks. The frameworks could be widely used for other different building systems and beyond buildings, such as transportation or industrial manufacturing systems.</p>

The object of this project was to develop a device, which would by use to coordinate or control device wireless. The system divided to several independent devices, which assure high comfort for the user. The basic unit contains of touch panel which allow the user to control the system. The second unit is used for communication the system with GSM net. The third unit is used to coordinate the system from a PC. This unit makes possible data collection and their evaluation. This unit can as well control and coordinate any devises in the system. Part and parcel of this system are units which are used to drive the end consumers. The hole system is powered from a instead powers supply which is managed from a microprocessor. These devices make it possible, to the system to work without line voltage. The system is designed modular, so in the future it is possible to expand the system of others peripherals.

Au cours des dernières décennies, le développement rapide de la technologie sans fil et micro-électronique a provoqué un profond impact sur notre vie quotidienne. Parallèlement à la tendance, les technologies d'assistance ont été révolutionnées en termes de miniaturisation et de portabilité. Les traditionnels encombrants systèmes de dispositifs aidés, à connexion filaire sont maintenant remplacés par d'autres plus compacts, légers et portables. Le nombre de personnes aveugles et ayant une déficience visuelle continue à faire face à de nombreuses difficultés dans la vie quotidienne, en particulier dans la mobilité et la navigation. La théorie de la substitution sensorielle dans laquelle l'information obtenue d'une modalité sensorielle, peut atteindre les structures du cerveau physiologiquement par d'autres modalités sensorielles; par conséquent, il est possible pour les personnes aveugles et malvoyantes d'obtenir les informations désirées par d'autres sens. Sur la base de ces technologies et principes, nous voulons améliorer le Tongue Display Unit, un dispositif de visio-tactile lingual a été inventé par le professeur Bach-y-Rita à un, dispositif à long terme sans fil portable pour la navigation. Afin de rendre ce dispositif autonome, certaines propriétés doivent être étudiées: l'optimisation de la consommation d'énergie (à faire à long terme) et la communication sans fil efficace. Nous avons fait un examen très détaillé afin de choisir les composants optimaux et la méthode adéquate pour notre système. La conception du matériel a été effectuée en choisissant le meilleur algorithme. Le module émetteur-récepteur sans fil basé sur ZigBee contribue à réduire la consommation globale d'énergie. Notre antenne omnidirectionnelle est appropriée pour une utilisation chez les personnes aveugles qui ne peuvent pas être orientés à l'avance. Nous avons modifié tous les composants de la TDU, du matériel au logiciel, à partir du contrôleur à l'actionneur. La conception de l'ensemble d'électrodes n'est pas rectangulaire comme traditionnellement mais sous une forme ronde avec un soutien utilisé pour la direction et à la navigation. Enfin, le système a été validé par TDU fonctionnement en temps réel et testé sur les utilisateurs réels. Les performances du système en termes de design et d'énergie ont été améliorées. La communication sans fil est plus efficace et consomme moins d'énergie. Les premiers résultats sur les essais des utilisateurs montrent une assez bonne perception de notre TDU. / Over the last decades, the rapid development of wireless technology and microelectronic has caused a profound impact on our daily lives. Alongside the trend, assistive technologies have revolutionized in terms of miniaturization and wearability. The traditional bulky aided devices systems with wired connection are now replaced by the compact, lightweight and portable ones. The number of blind and visually impaired people continues to deal with many difficulties in daily lives, especially in mobility and navigation. The theory of sensory substitution in which information gained from one sensory modality can reach brain structures physiologically through other sensory modalities; therefore, it is possible for the blind and visually impaired people to get desired information via other senses. Based on these technologies and principles, we want to enhance the Tongue Display Unit, a lingual visuo-tactile device was invented by Professor Bach-y-Rita to a wireless, wearable, long-term device for navigation. In order to make such device, some properties have to be studied: optimization of energy consumption (to make it long-term) and efficient wireless communication. We made a very detailed review in order to choose the optimal components and method for our system. The hardware design was calculated and selected the best algorithm. The ZigBee-based wireless transceiver module contributes to reducing the overall power consumption. Our omnidirectional antenna is appropriate for usage in blind people who cannot orient in advance. We modified all components of the TDU, from the hardware to software, from controller to actuator. The design of the electrode array is not rectangular as traditional but in a round shape which is supportively used for direction and navigation. Lastly the TDU system was validated by real-time operation and tested on real users. The performance of the system in terms of design and energy has been improved. The wireless communication is more effective and consumes less power. The primary results on users' trials show rather good perception on our TDU.

Orientador: Edmundo Roberto Mauro Madeira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-23T07:19:08Z (GMT). No. of bitstreams: 1 OliveiraFilho_JorgeLimade_D.pdf: 4901235 bytes, checksum: e6b9bb2a16e6d8b4b4cac7d26265847a (MD5) Previous issue date: 2013 / Resumo: Atualmente há uma necessidade das pessoas estarem conectadas a todo o momento e em qualquer lugar utilizando seus MNs (Mobile Nodes) para realizarem suas tarefas. É desejável uma Internet disponível a todo instante. Porém, a integração das redes sem fio de tecnologias diferentes apresenta vários desafios, como por exemplo, manter a continuidade dos serviços que rodam no MN quando há uma troca de rede. Percebendo a demanda crescente por mobilidade e de uma necessidade de uma Internet ubíqua, o IEEE padronizou um conjunto de serviços e protocolos com o intuito de integrar as redes de diferentes tecnologias denominadas IEEE 802.21. Entretanto, não fazem parte do padrão alguns mecanismos necessários para suportar mobilidade nas redes heterogêneas, como por exemplo, o algoritmo de decisão para a escolha da rede e o mecanismo de gerência de handover. Além disso, a demanda por mobilidade exige um mecanismo de gerência diferenciado devido à heterogeneidade dos elementos e a dinâmica do ambiente das redes sem fio heterogêneas. Para lidar com esses desafios, este trabalho apresenta uma arquitetura de gerência de mobilidade cognitiva para redes sem fio heterogêneas. Essa arquitetura é baseada no IEEE 802.21 e é capaz de integrar diversas redes com tecnologias diferentes e de suportar mobilidade mantendo a continuidade dos serviços quando o MN troca de uma rede para outra. Foi desenvolvido para esta arquitetura um algoritmo cognitivo de decisão de handover que seleciona as redes baseado nas experiências prévias dos MNs. Esse algoritmo utiliza como métrica de decisão as perdas dos fluxos TCP configurados nos MNs. O módulo cognitivo embutido na arquitetura foi uma evolução do resultado de pesquisa da nossa proposta de um algoritmo cognitivo para reconfiguração dos parâmetros do IEEE 802.11, denominado CogMAC. O CogMAC é uma proposta descentralizada, ou seja, os MNs que o implementam não possuem uma visão total da rede, cada MN individualmente é capaz de monitorar o desempenho e reconfigurar os parâmetros da subcamada MAC para evitar degradação do desempenho devido a mudanças nas condições da rede. O CogMAC é avaliado através de simulações e de um testbed real e os resultados comparados confirmam sua eficácia. Já a arquitetura de gerência cognitiva é avaliada através de simulações, e os resultados são comparados com o algoritmo que prioriza a conexão das redes WiFi. Os resultados obtidos confirmam também o bom desempenho da arquitetura proposta / Abstract: The mobile nodes (MNs) have become popular nowadays, the rapid increase in the use of wireless technologies has changed the behavior of individuals and businesses in the way they communicate. Currently, there is a demand for people to be connected all time and everywhere by using their MNs to perform their tasks. It is desirable to have a ubiquitous Internet, available at any moment and everywhere. However, the integration of heterogeneous wireless networks introduces several challenges. One of the most challenging issues is service continuity during handovers. As a result of the high demand for mobility, IEEE has created a set of services and protocols in order to integrate heterogeneous networks, called IEEE 802.21. However, there are no mechanisms in the standard in order to support mobility in heterogeneous networks, such as decision algorithms and mechanisms to perform the handover. Moreover, the mobility demand requires a special management mechanism due to the elements' diversity and the dynamic environment of the heterogeneous wireless networks. In order to tackle these challenges, this work presents cognitive mobility management architecture for heterogeneous wireless networks. This architecture is based on the IEEE 802.21 and is able to integrate different networks with different technologies and supporting mobility while maintaining service continuity when the MN performs a handover. A handover decision algorithm was developed for this architecture to select networks based on the previous experiences of MNs. This algorithm uses as decision metric the TCP loss in the MNs. The cognitive module in the architecture is an evolution of research results of our proposed algorithm for reconfiguration of cognitive parameters of the IEEE 802.11, called CogMAC. The CogMAC is a completely distributed proposal capable to monitor the MAC layer performance and react to changes to avoid performance degradation. The CogMAC is evaluated by simulations and real testbed and the results are compared with the first-WiFi algorithm. This algorithm prioritizes the connection of WiFi networks. The results also confirm the good performance of the proposed architecture / Doutorado / Ciência da Computação / Doutor em Ciência da Computação