The thesis deals with the analysis and the reception of the freely available signals of the navigation satellites in the L1 and E1 bands of the GPS and Galileo systems. The described signal reception sections include the process of the acquisition, the carrier frequency and phase synchronization and tracking, the spreading code phase tracking, the signal demodulation and the channel decoding. The simulation of the entire receiver is performed in MATLAB. The deeply analyzed signal reception component is the one responsible for the carrier phase and frequency synchronization and tracking. In that case, more methods and their comparison are usually listed. The signal reception component, which is responsible for the carrier phase and frequency tracking and the spreading code phase tracking, is also implemented in FPGA.

Les réseaux de capteurs sans fil (WSN) jouent un rôle important dans des applications telles que la surveillance de l'environnement, le suivi de sources et le suivi médical, ...etc. Dans les WSN, les capteurs ont la capacité d'effectuer l'échantillonnage des données, des calculs distribués et de fusionner des données. Pour effectuer ces tâches complexes, la synchronisation des horloges et la localisation sont fondamentales et essentielles. Les WSN ont été largement étudiés ces dernières années et la littérature scientifique rapporte de nombreux résultats qui les rendent applicables pour de nombreuses applications. Pour d'autres, la recherche doit encore trouver des solutions à certains des défis posés par la limitation énergétique, la dynamicité et la faible puissance de calcul. Dans le but de contribuer à la recherche sur les WSN, cette thèse propose de nouveaux algorithmes pour la synchronisation d'horloge et la localisation. La synchronisation d'horloge est nécessaire afin que les effectuent de manière efficace la fusion de données. En appliquant l'algorithme de synchronisation d'horloge, les capteurs établissent un consensus temporel et travaillent donc au même rythme. Compte tenu de la dynamicité, des faibles capacités de calcul et de la parcimonie des WSN, un nouvel algorithme de synchronisation décentralisée à impulsions couplées est proposé pour améliorer la précision de la synchronisation. L'avantage de ce type d'algorithme est que les capteurs échangent des impulsions au lieu de paquets, de sorte que non seulement la communication est efficace, mais aussi robuste à toute défaillance des capteurs dans le réseau. La localisation de capteurs a été largement étudiée dans la littérature scientifique. Cependant, la qualité et la précision de la localisation peuvent encore être améliore. Cette thèse applique l'algorithme LSCR (Régression de régions corrélées à signes dominants) au problème de localisation. Avec LSCR, on évalue des régions de confiance avec des niveaux de confiance prescrits, qui fournissent non seulement on emplacement mais aussi la confiance en cet emplacement. Dans cette thèse, plusieurs approches de localisation sont implémentées et comparées. Le résultat de la simulation montre que, sous hypothèses modérées, LSCR obtient des résultats compétitifs par rapport à d'autres méthodes. / Wireless sensor networks (WSNs) play an important role in applications such as environmental monitoring, source tracking, and health care,... In WSN, sensors have the ability to perform data sampling, distributed computing and information fusion. To perform such complex tasks, clock synchronization and localization are two fundamental and essential algorithms. WSNs have been widely studied in the past years, and the scientific literature reports many outcomes that make them applicable for some applications. For some others, research still needs to find solutions to some of the challenges posed by battery limitation, dynamicity, and low computing clock rate. With the aim of contributing to the research on WSN, this thesis proposes new algorithms for both clock synchronization and localization. For clock synchronization, sensors converge their local physical clock to perform data fusion. By applying the clock synchronization algorithm, sensors converge the time difference and therefore work at the same rate. In view of dynamicity, low computing and sparsity of WSN, a new pulse-coupled decentralized synchronization algorithm is proposed to improve the precision of the synchronization. The benefit of this kind of algorithm is that sensors only exchange zero-bit pulse instead of packets, so not only the communication is efficient but also robust to any failure of the sensors in the network. Localization of sensors has been widely studied. However, the quality and the accuracy of the localization still have a large room to improve. This thesis apply Leave-out Sign-dominant Correlated Regions (LSCR) algorithm to localization problem. With LSCR, one evaluates the accurate estimates of confidence regions with prescribed confidence levels, which provide not only the location but also the confidence of the estimation. In this thesis, several localization approaches are implemented and compared. The simulation result shows under mild assumptions, LSCR obtains competitive results compared to other methods.

<p>  </p> <p><strong>OBJECTIVES:</strong> Medication synchronization (med-sync) aligns patients’ chronic medications to a predetermined routine pickup date at a community pharmacy. An appointment-based model (ABM) med-sync service includes a comprehensive medication review at the pharmacy. We had the following objectives: (1) To systematically characterize literature describing healthcare utilization, cost clinical, and humanistic outcomes for patients enrolled in medication synchronization, (2) to determine the characteristics of Medicare Part D beneficiaries’ receipt of medication synchronization program and (3) to compare healthcare utilization outcomes of Medicare beneficiaries enrolled in an ABM med-sync program to beneficiaries not enrolled in such a program.</p> <p><br></p> <p><strong>METHODS:</strong> A systematic literature review was conducted using electronic databases from January 2008 to October 2022. The retrospective cohort study analyzed Medicare claims data from 2014-16 for a sample of 1 million beneficiaries utilizing community pharmacies identified as offering a med-sync program. Medicare inpatient, outpatient, emergency, and pharmacy claims data were used to create med-sync and non-med-sync cohorts. We applied Andersen’s Health Services Utilization model to determine factors associated with med-sync enrollment. We constructed logistic regression models with med-sync enrollment as the dependent variable adding predisposing, enabling, and need variables. Descriptive statistics and bi-variate analysis were performed on the cohorts. All patients were followed longitudinally for 12 months before and after a 2015 index/enrollment month to calculate healthcare utilization. Difference-in-differences (DID) was used to compare mean changes in utilization outcomes between cohorts before and after enrollment.</p> <p><br></p> <p><strong>RESULTS:</strong> Through systematic review, we found limited studies related to costs and healthcare utilization. Med-sync programs have shown to increase drug adherence to medications and improve patient satisfaction. For our study with Medicare beneficiaries, we identified 13,193 beneficiaries in the med-sync cohort and 156,987 beneficiaries in non-med sync (control) cohort. As age of beneficiaries increased, likelihood of med-sync enrollment increased (AOR=1.003, 95% CI:1.001-1.005). There were ​higher odds of enrollment for beneficiaries residing in Northeast (AOR=1.094, 95% CI:1.018-1.175), South (AOR=1.109, 95% CI:1.035-1.188), and West (AOR=1.113, 95% CI:1.020-1.215) than the Midwest. Beneficiaries residing in non-metro areas had lower odds of enrollment​ (AOR: 0.914, 95% CI: 0.863-0.969) than metro areas. Beneficiaries with less previous inpatient hospitalizations (AOR=0.945, 95% CI:0.914-0.977) were less likely to be enrolled whereas those with higher outpatient visits (AOR=1.003, 95% CI:1.001-1.004) were more likely to be enrolled. Beneficiaries taking a higher number of oral chronic medications (AOR=1.005, 95% CI:1.002-1.008) had greater odds of enrollment in med-sync. After propensity matching, 13,193 beneficiaries in each cohort were used for analysis. Mean pharmacy utilizations increased before and after enrollment for both cohorts while mean outpatient utilization decreased before and after enrollment for med-sync cohort only. Healthcare utilization mean DID were significantly less in the med-sync cohort compared to the non-med-sync cohort for outpatient visits (DID: 0.01, p=0.0073) and pharmacy fills (DID: 0.01, p<0.0001). There was no significant DID for inpatient and emergency visits between cohorts.</p> <p><br></p> <p><strong>CONCLUSION:</strong> Disparities in age, geographic region, type of residence and prior health utilization for med-sync enrollment were identified. Outpatient and pharmacy utilization changes were significantly lower in med-sync cohort compared to the non-med-sync cohort in the 12-months after enrollment. Lower pharmacy utilization could be due to optimization of therapy during medication reviews of ABM med-sync. As Medicare is approaching to a value-based system, there needs to be a greater focus on systems such as med-sync that has shown to improve a patient’s adherence. </p>

No description available.

Short range wireless data communication networks that are used for sport and health care are sometimes called Wireless Body Area Networks (WBANs) and they are located more or less on a person. Sole Integrated Gait Sensor (SIGS) is a research project in WBAN, where wireless pressure sensors are placed like soles in the shoes of persons with different kinds of deceases. The sensors can measure the pressure of the foot relative to the shoe i.e. the load of the two legs is measured. This information can be useful e.g. to not over or under load a leg after joint replacement or as a bio feedback system to help e.g. post stroke patients to avoid falling. The SIGS uses the ANT Protocol and radio specification. ANT uses the 2.4 GHz ISM band and TDMA is used to share a single frequency. The scheduling of time slots is adaptive isochronous co-existence i.e. the scheduling is not static and each transmitter sends periodically but checks for interference with other traffic on the radio channel. In this unidirectional system sole sensors are masters (transmitters) and the WBAN server is the slave in ANT sense. The message rate is chosen as 8 Hz which is suitable for low power consumption. Hence in the SIGS system, it is necessary to synchronize the left and the right foot sensors because of low message rate. In our thesis, we found a method and developed a prototype to receive the time synchronized data in WBAN server from ANT wireless sensor nodes in SIGS system. For this thesis work, a hardware prototype design was developed. The USB and USART communication protocols were also implemented in the hardware prototype. The suitable method for time synchronization was implemented on the hardware prototype. The implemented method receives the sensor data, checks for the correct stream of data; add timestamp to the sensor data and transmit the data to the Linux WBAN server. The time slots allocation in the ANT protocol was found. Alternative solution for the time synchronization in ANT protocol was also provided. The whole SIGS system was tested for its full functionality. The experiments and analysis which we performed were successful and the results obtained provided good time synchronization protocol for ANT low power wireless sensor network and for Wireless Bio-feedback system.

The objective of this research work is to develop reliable and power-efficient synchronization algorithms for continuous phase modulation (CPM). CPM is a bandwidth and power efficient signaling scheme suitable for wireless and mobile communications. Binary CPM schemes have been widely used in many commercial and military systems. CPM with multilevel symbol inputs, i.e., M-ary CPM, can achieve a higher data rate than binary CPM. However, the use of M-ary CPM has been limited due to receiver complexity and synchronization problems. In the last decade, serially concatenated CPM (SCCPM) has drawn more attention since this turbo-like coded scheme can achieve near Shannon-limit performance by performing iterative demodulation/decoding. Note that SCCPM typically operates at a low signal-to-noise ratio, which makes reliable and power-efficient synchronization more challenging. In this thesis, we propose a novel timing and phase recovery technique for CPM. Compared to existing maximum-likelihood estimators, the proposed data-aided synchronizer can achieve a better acquisition performance when a preamble is short or channel model errors are present. We also propose a novel adaptive soft-input soft-output (A-SISO) module for iterative detection with parameter uncertainty. In contrast to the existing A-SISO algorithms using linear prediction, the parameter estimation in the proposed structure is performed in a more general least-squares sense. Based on this scheme, a family of fixed-interval A-SISO algorithms are utilized to implement blind iterative phase synchronization for SCCPM. Moreover, the convergence characteristics of iterative phase synchronization and detection are analyzed by means of density evolution. Particularly, an oscillatory convergence behavior is observed when cycle slips occur during phase tracking. In order to reduce performance degradation due to this convergence fluctuation, design issues, including delay depth of the proposed algorithms, iteration-stopping criteria and interleaver size, are also discussed. Finally, for completeness of the study on phase synchronization, we investigate the error probability performance of noncoherently detected full-response CPM, which does not require channel (or phase) estimation.

Wideband measurements of the mobile-to-mobile channel, especially of the harshest channels, are necessary for proper design and certification testing of mobile-to-mobile communications systems. A complete measurement implies that the Doppler and delay characteristics are measured jointly. However, such measurements have not previously been published. The main objective of the proposed research is to develop channel models for specific scenarios from data obtained in a wideband mobile-to-mobile measurement campaign in the 5.9 GHz frequency band. For this purpose we developed a channel sounding system including a novel combined waveform. In order to quantify and qualify either the recorded channel or the proposed generated channel, we developed a simulation test-bed that includes all the characteristics of the proposed digital short range communications (DSRC) standard. The resulting channel models needed to comply with the specifications required by hardware channel emulators or software channel simulators. From the obtained models, we selected one to be included in the IEEE 802.11p standard certification test. To further aid in the development of software radio based receivers, we also developed an orthogonal frequency division multiplexing (OFDM) synchronization algorithm to analyze and compensate synchronization errors produced by inaccessible system clocks.

Frame synchronization is an important problem in digital communication systems. In frame synchronization, the main task is to find the frame start given the flow of the communication symbols. In this thesis, frame synchronization problem is investigated for both additive white Gaussian noise (AWGN) channels and frequency selective channels. Most of the previous works on frame synchronization consider the simple case of AWGN channels. The algorithms developed for this purpose fail in frequency selective channels. There is limited number of algorithms proposed for the frequency selective channels. In this thesis, existing frame synchronization techniques are investigated for both AWGN and frequency selective channels. Code-aided frame synchronization techniques are combined with the methods for frequency selective channels. Mainly two types of code-aided frame synchronization schemes are considered and two new system structures are proposed for frame synchronization. One of the proposed structures performs better than the alternative methods for frequency selective channels. The overall system for this new synchronizer is composed of a list synchronizer which generates the possible frame starts, a channel estimator, a soft output MLSE equalizer, and a soft output Viterbi decoder. A mode separation algorithm is used to generate the statistics for the selection of the true frame start. Several experiments are done and the performance is outlined for a variety of scenarios.

For large multihop networks, the time synchronization (TS) error accumulates as the hop number increases with conventional methods, such as Timing-sync Protocol for Sensor Networks (TPSN), Reference Broadcast Synchronization (RBS), and Flooding Time Synchronization Protocol (FTSP). In this paper, to reduce the number of hops to cover the large network and exploit the spatial averaging of TS error between clusters, a novel method combining Concurrent Cooperative Transmission (CCT) and Semi-Cooperative Spectrum Fusion (SCSF) is proposed. This novel method named Cooperative Analog and Digital (CANDI) Time Synchronization protocol consists of two phases: The digital stage and the analog stage. The digital stage uses CCT to broadcast TS packet containing the time information. Cooperating nodes transmit the digitally encoded message in orthogonal channels simultaneously, so the receiver combines the multiple packet to acheive significant SNR advantage. In the analog stage, the cooperating nodes simultaneously transmit their slightly different individual estimates of the propagation time by using frequency shift modulation. Nodes receiving this signal combat fading and reduce estimation error in one step through the averaging inherent in diversity combining. Simulation results for two-dimension (2-D) networks are given to evaluate the performance of CANDI, and CANDI is compared with TPSN.

Made available in DSpace on 2016-03-15T19:37:54Z (GMT). No. of bitstreams: 1 Fernando Biazi Nascimento.pdf: 3885211 bytes, checksum: 52d266afc3ffddce2e0abc915e2471a1 (MD5) Previous issue date: 2014-10-23 / Fundo Mackenzie de Pesquisa / The present work consists of an implementation of time distribution protocol based on PTP disclosed in the IEC 61588:2009 / IEEE 1588-2008 standard to be used in low-power wireless devices. The distribution of time is important to determine the order of occurrence of events marked in distinct counts that can then be related. And the problems of lack of synchronicity are evident in circumstances ranging from the study of historical facts up to the investigation of intruders in modern equipments connected to the internet. The work included development of a completely new software for the microcontroller MSP430F2274TM using the CC2480TMnetwork controller. The implementation of the protocol considers one of the mechanisms described by the standard and remains very close to it, not fully conformant mainly because of lack of resources on the used device, but the expected behavior was kept. The devices synchronize the time between them and sintonize their time counting, in a way to reduce, as much as possible, the adjustments of further synchronizations. / O presente trabalho consiste em uma implementação de protocolo de distribuição de tempo baseado no PTP, definido na norma IEC 61588:2009/IEEE 1588-2008 a ser utilizado em dispositivos sem fio de baixo consumo de energia. A distribuição de tempo é importante para determinar a ordem de ocorrência de eventos marcados em contagens distintas que podem então ser relacionadas. E os problemas de falta de sincronia são evidentes em circunstâncias que vão de estudo de fatos históricos até a verificação de intrusos em equipamentos modernos conectados à internet. O trabalho contou com desenvolvimento de um software completamente novo para o micro-controlador MSP430F2274TM utilizando o controlador de rede CC2480TM. A implementação do protocolo considera um dos mecanismos apresentados pela norma e ficou muito próxima, não atendendo-a plenamente principalmente por falta de recursos no dispositivo utilizado, mas manteve o comportamento previsto. Os dispositivos sincronizam os tempos entre eles e sintonizam suas contagens de tempo, de forma a reduzir, tanto quanto possível, o ajuste de futuras sincronizações.