Spectrum Sharing, Latency, and Security in 5G Networks with Application to IoT and Smart Grid

The surge of mobile devices, such as smartphones, and tables, demands additional capacity. On the other hand, Internet-of-Things (IoT) and smart grid, which connects numerous sensors, devices, and machines require ubiquitous connectivity and data security. Additionally, some use cases, such as automated manufacturing process, automated transportation, and smart grid, require latency as low as 1 ms, and reliability as high as 99.99\%. To enhance throughput and support massive connectivity, sharing of the unlicensed spectrum (3.5 GHz, 5GHz, and mmWave) is a potential solution. On the other hand, to address the latency, drastic changes in the network architecture is required. The fifth generation (5G) cellular networks will embrace the spectrum sharing and network architecture modifications to address the throughput enhancement, massive connectivity, and low latency. To utilize the unlicensed spectrum, we propose a fixed duty cycle based coexistence of LTE and WiFi, in which the duty cycle of LTE transmission can be adjusted based on the amount of data. In the second approach, a multi-arm bandit learning based coexistence of LTE and WiFi has been developed. The duty cycle of transmission and downlink power are adapted through the exploration and exploitation. This approach improves the aggregated capacity by 33\%, along with cell edge and energy efficiency enhancement. We also investigate the performance of LTE and ZigBee coexistence using smart grid as a scenario. In case of low latency, we summarize the existing works into three domains in the context of 5G networks: core, radio and caching networks. Along with this, fundamental constraints for achieving low latency are identified followed by a general overview of exemplary 5G networks. Besides that, a loop-free, low latency and local-decision based routing protocol is derived in the context of smart grid. This approach ensures low latency and reliable data communication for stationary devices. To address data security in wireless communication, we introduce a geo-location based data encryption, along with node authentication by k-nearest neighbor algorithm. In the second approach, node authentication by the support vector machine, along with public-private key management, is proposed. Both approaches ensure data security without increasing the packet overhead compared to the existing approaches

Redes de acesso em fibra ótica : situação atual e evolução

Trabalho final de mestrado para a obtenção do grau de Mestre em Engenharia de Eletrónica e TelecomunicaçõesAs redes de acesso ótico, têm sido consideradas uma solução definitiva para o problema da limitação de largura de banda quando comparadas com outras soluções. Por essa razão, as redes PON (Passive Optical Network) têm tido um crescimento enorme nos últimos anos, oferecendo diversas soluções ao cliente final quer este seja residencial ou empresarial. O sucesso desta tecnologia é tal, que a penetração do serviço tem batido recordes de adesão dadas as vantagens das fibras óticas. Pretende-se com esta dissertação, dimensionar uma rede GPON (Gigabit Passive Optical Network) numa área de cobertura da zona de Lisboa, para ser explorada por duas operadoras concorrentes. Para tal, utilizou-se o software AutoCad com cartografia georreferenciada da zona de cobertura em questão. A rede foi projetada para uma taxa de penetração de 100 % (50 % para cada operadora). Dividiu-se a zona de cobertura em células e posteriormente em microcélulas, sendo que para cada edifício aí existente foram projetadas fibras ativas para alimentar os diferentes ONTs (Optical Network Terminal) na rede do cliente. De igual forma, projetaram-se também os equipamentos passivos a serem instalados na célula projetada, desde o CO (Central Office), ao ODN (Optical Distribution Network) até a rede do cliente. De seguida, fez-se o levantamento destes equipamentos e avaliou-se a viabilidade económica da rede GPON implementada, bem como o tempo de retorno do investimento inicial. Finalmente, introduziu-se a tecnologia XGPON (10-Gigabit-capable Passive Optical Network) sobre a mesma rede de acesso, permitindo desta forma ter uma oferta maior em termos de largura de banda. Em termos médios, pode afirmar-se que o custo de implementação de uma célula ronda valores entre 150 000 € e 200 000 €, sendo que o tempo de retorno é de cerca de um ano e três meses ou um ano e seis meses, dependendo da taxa de penetração dos serviços solicitados pelos diferentes clientes.Optical access networks have been considered a definitive solution to the problem of bandwidth limitation when compared to other solutions. For this reason, Passive Optical Network (PON) networks have grown tremendously in recent years, offering a number of solutions to the end customer whether residential or business. The success of the technology is such that service penetration has hit accession records given the advantages of optical fibers. This dissertation intends to design a GPON (Gigabit Passive Optical Network) network in a coverage area of the Lisbon zone, to be exploited by two competing operators. For such, used the AutoCad software with georeferenced mapping of the coverage area in question. The network is designed for a penetration rate of 100% (50% for each operator). The coverage zone was divided into cells and then into microcells, being that for each building there was designed active fibers to power the different ONTs (Optical Network Terminal) on the customer network. Likewise, the passive equipment to be installed in the projected cell, from the CO (Central Office), to the Optical Distribution Network (ODN) till customer network, was also designed. Then, the equipment was surveyed and the economic viability of the implemented GPON network was evaluated, as well as the time of return of the initial investment. Finally, XGPON (10-Gigabit-capable Passive Optical Network) technology was introduced on the same access network, allowing in this way to have a greater offer in terms of bandwidth. In average terms, it can be stated that the cost of implementing a cell ranges from € 150,000 to € 200,000, with the payback time being about one year and three months or a year and six months depending of the penetration rate of the services requested by the different clients.N/

Mobile Networks

The growth in the use of mobile networks has come mainly with the third generation systems and voice traffic. With the current third generation and the arrival of the 4G, the number of mobile users in the world will exceed the number of landlines users. Audio and video streaming have had a significant increase, parallel to the requirements of bandwidth and quality of service demanded by those applications. Mobile networks require that the applications and protocols that have worked successfully in fixed networks can be used with the same level of quality in mobile scenarios. Until the third generation of mobile networks, the need to ensure reliable handovers was still an important issue. On the eve of a new generation of access networks (4G) and increased connectivity between networks of different characteristics commonly called hybrid (satellite, ad-hoc, sensors, wired, WIMAX, LAN, etc.), it is necessary to transfer mechanisms of mobility to future generations of networks. In order to achieve this, it is essential to carry out a comprehensive evaluation of the performance of current protocols and the diverse topologies to suit the new mobility conditions