DESIGN AND ANALYSIS OF EFFICIENT OPTICAL NETWORKS FOR SMART CITIES

Abstract

All over the world, the concept of smart cities is taking a boom. The smart city is defined as a paradigm, predominantly made up of information and communication-based technologies. Smart cities are using these technologies to handle the ever-increasing urbanization challenges by practicing sustainable development and making human life smarter, easier, and more pro ductive without imparting any negative consequences on human life. Smart city applications like smart home, smart hospital, smart transport, smart education, smart agriculture etc. gen erates a huge amount of data that needs to be processed and transmitted. With this increasing bandwidth requirements in smart cities, there is a need for high-capacity optical networks featuring ultrahigh bandwidths. Conventional Single Core Fibers (SCF) has a limited bandwidth which are not suitable for future bandwidth hungry applications of smart cities. So, there is a need to boost and modernize the current optical transmission fiber for these applications. Multi-Core Fibers (MCF) is recognized as a possible solution enabling high capacity data transmission in smart cities. MCF have multiple cores enclosed in a sin gle cladding, which increases the transmission capacity by as many folds as the number of cores they have. This research introduces, for the first time, novel 21-core homogeneous MCF structure with three different types of core placement layouts (1-Ring, 2-Ring, and Square Lattice) to densely pack the cores with a minimum cladding diameter of 200µm, to support high-speed smart city applications. All the three structures have been designed with a low RI Trench-Assisted (TA) profile to significantly reduce the Inter-Core Crosstalk (ICXT). The results shows that, among all structures, the TA Square Lattice core arrangement has the min imum ICXT value, i.e., approximately -60dB/100Km, because of its largest core-to-core dis tance. To further suppress the crosstalk, air holes have been placed between the TA cores. Placing the low-index air-hole shield closer to the trench enhances the modal confinement within relatively large trench-assisted core structures. The MCF structures further extended with 31 and 37 TA and air-hole-assisted cores with reduced ICXT of -70dB for 100Km of fiber length. The air-hole pairs and triplets are placed between adjacent TA cores in order to further suppress modal field overlap. The performance evaluation of the designed MCFs has v been carried out for a large number of design parameters. The current existing static and dynamic optical networks cannot efficiently optimize network resources and do not support intelligent decision-making for smart cities, rendering them en ergy inefficient. In this thesis, a novel Software-Defined Network (SDN)-controlled dynami cally reconfigurable Time Division Multiplexing (TDM) and Dense Wavelength-Division Mul tiplexing (DWDM)-based Elastic Optical Network (EON) for smart cities have been designed and simulated, which maximizes the utilization of network resources, making it energy ef ficient. To enhance the decision making of the SDN controller, three algorithms have been developed i.e. Inter-Application Wavelength Redirection (IAWR) with ROADM, Dynamic Load Balancing (DLB), and Bandwidth Selection with Resource Allocation (BSRA) based on the different bandwidth requirements of primary and secondary applications of smart city. These algorithms sense the free bandwidth in primary applications and then assign this free bandwidth to secondary applications accordingly. The proposed SDN controller selects the best algorithm that optimally utilizes the network resources and routes the traffic through it. The performance of the designed EON for a smart city is analyzed and a three way correlation is designed between various input parameters with respect to different smart city applications and performance parameters such as the user satisfaction rate, timing diagrams, eye diagrams, bit error rate and quality factor. The proposed algorithms utilize the network resources more efficiently and helped to maintain the required quality of service. The smart city architecture require the convergence of wireless and optical communication network, where data is fetched from sensors in wireless form and then transmitted through optical channel. So, a MIMO based hybrid wireless and optical communication system has been designed using MCF. For wireless channel, the benefits of Coded Cooperation (CC) have been exploited and merged with Cognitive Radio (CR) for the collection of data wirelessly from all the primary and secondary applications of smart cities. Then, an MCF-based MIMO optical network has been designed for the smart city application and its performance has been analyzed. The results evaluated in this thesis show significant improvement over the available results of the previous research.