A presença da tecnologia da informação dentro do agronegócio tem avançado e contribuído para a obtenção de melhores resultados para a gestão e, consequentemente, para o proprietário rural. Uma área de pesquisa que tem avançado dentro do setor rural é o monitoramento e a coleta de dados dos animais, em tempo real, possibilitando ao proprietário rural gerenciar seu rebanho, sem a necessidade de se deslocar ao local monitorado ou ao ponto de coleta de dados. A utilização das redes de sensores sem fio para fins de monitoração ainda possui limitações, como por exemplo a limitação do alcance do sinal de transmissão entre os nós sensores. Atualmente as tecnologias de transmissão de dados sem fio em uma rede de sensores alcançam pequenas distâncias, limitando o processo de detecção e coleta dos dados às áreas de pastagem menores. Assim, esta pesquisa teve como objetivo avaliar, através de simulação computacional, dois tipos de protocolos de comunicação sem fio que têm potencial para serem utilizados no monitoramento de sistemas de produção animal em longas distâncias: o protocolo ZigBee e o IEEE 802.1ah. Para a realização das simulações foram utilizados os softwares OMNet++ 4.5 e uma ferramenta de extensão chamada Mixim. Para tanto, foram criados dois cenários (ambientes) para cada protocolo, onde foram definidos: a área de cobertura, em torno de 1.500 metros, topologia da rede sem fio do tipo estática, dois nós para comunicação (um coordenador e um receptor) e as características do cenário. Por meio dos resultados obtidos através de simulação computacional com aplicação das métricas: distância, latência e taxa de perda de pacotes de dados nas simulações, observou-se que o protocolo ZigBee obteve o melhor desempenho em relação à distância de cobertura do sinal e da confiabilidade dos dados transmitidos. / The presence of information technology within the agribusiness has advanced and contributed to better results for the management and, consequently, to the landowner. One area of research that has advanced into the rural sector is the monitoring and collection of animal data in real time, allowing the landowner to manage his herd, without the need to move to the monitored site or the data collection point. However the technology of wireless sensor networks used for this purpose, has limitations and one of them is the signals range factor because, in order to make the data collection is necessary to install sensors and antennas in the pasture to reach the signals. Currently, wireless data transmission technologies in a network of sensors reach short distances, limiting the detection process and data collect to smaller pasture areas. This study aimed to find a long-distance transmission solution to reach areas of larger proportions pastures, and offer the landowner new monitoring resources. The methodology used to find such a solution was through simulations, using two transmission technologies: ZigBee and IEEE 802.11ah. To perform the simulations it was used the OMNet++ software, version 4.5 and an extension tool, called the Mixim. It was created two scenarios (environments) for each protocol, where has been defined: the coverage area of about 1,500 meters, network topology wireless static type, two nodes for communication (a coordinator and a receiver) and the characteristics of the environment. Through the results obtained by computer simulation with application of the metrics: distance, latency and data packets loss rate in the simulations, it was observed that the ZigBee protocol had the best performance in relation to the signal coverage distance and the transmitted data reliability.

IEEE 802.11ah is designed to support battery powered devices that are required to serve for several years in the Internet of Things networks. The Restricted Access Window (RAW) has been introduced in IEEE 802.11ah to address the scalability of thousands of densely deployed devices. As the RAW sizes entail the consumed energy to support the transmitting devices in the network, hence the control mechanism for RAW should be carefully devised for improving the overall energy e ciency of IEEE 802.11ah. This thesis presents a two-stage adaptive RAW scheme for IEEE 802.11ah to optimise the energy efficiency of massive channel access and transmission in the uplink communications for highly dense networks. The proposed scheme adaptively controls the RAW sizes and device transmission access by taking into account the number of devices per RAW, retransmission mechanism, harvested-energy and prioritised access. The scheme has four completely novel control blocks: RAW size control that adaptively adjusts the RAW sizes according to different number of devices and application types in the networks. RAW retransmission control that improves the channel utilisation by retransmitting the collided packets at the subsequent slot in the same RAW. Harvested-energy powered access control that adjusts the RAW sizes with the consideration of the uncertain amount of harvested-energy in each device and channel conditions. Priority-aware channel access control that reduces the collisions of high-priority packets in the time-critical networks. The performance of the proposed controls is evaluated in Matlab under different net work scenarios. Simulation results show that the proposed controls improve the network performances in terms of energy efficiency, packet delivery ratio and delay as compared to the existing window control.

A presença da tecnologia da informação dentro do agronegócio tem avançado e contribuído para a obtenção de melhores resultados para a gestão e, consequentemente, para o proprietário rural. Uma área de pesquisa que tem avançado dentro do setor rural é o monitoramento e a coleta de dados dos animais, em tempo real, possibilitando ao proprietário rural gerenciar seu rebanho, sem a necessidade de se deslocar ao local monitorado ou ao ponto de coleta de dados. A utilização das redes de sensores sem fio para fins de monitoração ainda possui limitações, como por exemplo a limitação do alcance do sinal de transmissão entre os nós sensores. Atualmente as tecnologias de transmissão de dados sem fio em uma rede de sensores alcançam pequenas distâncias, limitando o processo de detecção e coleta dos dados às áreas de pastagem menores. Assim, esta pesquisa teve como objetivo avaliar, através de simulação computacional, dois tipos de protocolos de comunicação sem fio que têm potencial para serem utilizados no monitoramento de sistemas de produção animal em longas distâncias: o protocolo ZigBee e o IEEE 802.1ah. Para a realização das simulações foram utilizados os softwares OMNet++ 4.5 e uma ferramenta de extensão chamada Mixim. Para tanto, foram criados dois cenários (ambientes) para cada protocolo, onde foram definidos: a área de cobertura, em torno de 1.500 metros, topologia da rede sem fio do tipo estática, dois nós para comunicação (um coordenador e um receptor) e as características do cenário. Por meio dos resultados obtidos através de simulação computacional com aplicação das métricas: distância, latência e taxa de perda de pacotes de dados nas simulações, observou-se que o protocolo ZigBee obteve o melhor desempenho em relação à distância de cobertura do sinal e da confiabilidade dos dados transmitidos. / The presence of information technology within the agribusiness has advanced and contributed to better results for the management and, consequently, to the landowner. One area of research that has advanced into the rural sector is the monitoring and collection of animal data in real time, allowing the landowner to manage his herd, without the need to move to the monitored site or the data collection point. However the technology of wireless sensor networks used for this purpose, has limitations and one of them is the signals range factor because, in order to make the data collection is necessary to install sensors and antennas in the pasture to reach the signals. Currently, wireless data transmission technologies in a network of sensors reach short distances, limiting the detection process and data collect to smaller pasture areas. This study aimed to find a long-distance transmission solution to reach areas of larger proportions pastures, and offer the landowner new monitoring resources. The methodology used to find such a solution was through simulations, using two transmission technologies: ZigBee and IEEE 802.11ah. To perform the simulations it was used the OMNet++ software, version 4.5 and an extension tool, called the Mixim. It was created two scenarios (environments) for each protocol, where has been defined: the coverage area of about 1,500 meters, network topology wireless static type, two nodes for communication (a coordinator and a receiver) and the characteristics of the environment. Through the results obtained by computer simulation with application of the metrics: distance, latency and data packets loss rate in the simulations, it was observed that the ZigBee protocol had the best performance in relation to the signal coverage distance and the transmitted data reliability.

The promise of Internet of Things (IoT) and mass connectivity has brought many applications and along with them many new challenges to be solved. Recognizing sensor networks as one of the main applications of IoT, this dissertation focuses on solutions for IoT challenges in both single-hop and multi-hop communications. In single-hop communications, the new IEEE 802.11ah and its Group Synchronized Distribution Coordination Function (GS-DCF) is studied. GS-DCF categorized nodes in multiple groups to solve the channel contention issue of dense networks. An RSS-Based grouping strategy is proposed for the hidden terminal problem that can arise in infrastructure-based single hop communications. For multi-hop communications, Physical Layer Network Coding (PNC) is studied as a robust solution for multi-hop packet exchange in linear networks. Focusing on practical and implementation issues of PNC systems, different challenges have been addressed and a Software Defined Radio (SDR) PNC system based on USRP devices is proposed and implemented. Finally, extensive simulation and experimental results are presented to evaluate the performance of the proposed algorithms in comparison with currently used methods. / Graduate

This diploma thesis deals with the implementation of standard IEEE 802.11ah into network simulator NS-3. The first part of the diploma thesis describes M2M communication for which the standard IEEE 802.11ah would be suitable. M2M communication is being more and more used in the society, that is why there is an effort to develop a new standard for this type of communication. The thesis contains a description of this standard based on technical specifications brought out by the Task Group ah (TGah). Some changes have been made in NS-3 for the purpose of this thesis in order to support this standard. In the next part there is a created scenario with basic topology in NS-3 with usage of standard IEEE 802.11ah, in which the functionality of the standard is tested. The result of this diploma thesis is a description of the changes which have been made and analysis of the output files from the simulation.

In the past decades, wireless Machine-to-Machine (M2M) networks have been developed in various industrial and public service areas and envisioned to improve our daily life in next decades, e.g., energy, manufacturing, transportation, healthcare, and safety. With the advantage of low cost, flexible deployment, and wide coverage as compared to wired communications, wireless communications play an essential role in providing information exchange among the distributed devices in wireless M2M networks. However, an intrinsic problem with wireless communications is that the limited radio spectrum resources may result in unsatisfactory performance in the M2M networks. With the number of M2M devices projected to reach 20 to 50 billion by 2020, there is a critical need to solve the problems related to the design and applications in the wireless M2M networks. In this dissertation work, we study the wireless M2M networks design from three closely related aspects, the wireless M2M communication reliability, efficiency, and Demand Response (DR) control in smart grid, an important M2M application taking the advantage of reliable and efficient wireless communications. First, for the communication reliability issue, multiple factors that affect communication reliability are considered, including the shadowing and fading characteristics of wireless channels, and random network topology. A general framework has been proposed to evaluate the reliability for data exchange in both infrastructure-based single-hop networks and multi-hop mesh networks. Second, for the communication efficiency issue, we study two challenging scenarios in wireless M2M networks: one is a network with a large number of end devices, and the other is a network with long, heterogeneous, and/or varying propagation delays. Media Access Control (MAC) protocols are designed and performance analysis are conducted for both scenarios by considering their unique features. Finally, we study the DR control in smart grid. Using Lyapunov optimization as a tool, we design a novel demand response control strategy considering consumer’s comfort requirements and fluctuations in both the renewable energy supply and customers’ load demands. By considering those unique features of M2M networks in data collection and distribution, the analysis, design and optimize techniques proposed in this dissertation can enable the deployment of wireless M2M networks with a large number of end devices and be essential for future proliferation of wireless M2M networks. / Graduate / 0544 / flintlei@gmail.com

This diploma thesis deals with the analysis of the IEEE 802.11ah wireless communication system. For such a purpose, an appropriate simulation model in program environment MATLAB is created. The first part of thesis focuses on the IEEE 802.11 standard. Basic blocks of the transmitter and receiver are described. Attention is also devoted on the brief description of considered transmission channels. The second part contains the description of the proposed and realized simulation model in MATLAB. Individual blocks of the simulation model are described in details. Finally, the obtained simulation results are evaluated and discussed.