Spectrum-Efficient Routing In Elastic Optical Networks

With the rapid development of science and technology,emerging technologies such as big data,the Internet of Things,and artificial intelligence are increasingly being applied in industries and people’s daily lives,leading to a significant increase in communication traffic and a severe shortage of spectrum resources.Traditional fiber-optic networks can no longer meet the current demands for transmission capacity.In recent years,a new type of fiber-optic networks called Elastic Optical Network(EON)has been proposed to increase the transmission capacity of fiber-optic networks and meet the ever-growing communication traffic.EON essentially extends the transmission of fiber-optic networks by assigning a continuous number of subcarriers in allocation of spectrum resources.This new fiber-optic transmission technology has the potential to extend the lifespan of existing traditional fiber-optic infrastructure.By utilizing orthogonal frequency division multiplexing,EON can accommodate various requirements on the same fiber-optic link,not only saving capital for network expansions and improving network transmission speed,but also using the limited spectrum resources within the fiber-optic network more flexibly and thereby enhancing network security.Routing and Spectrum Allocation(RSA)is a major research problem in EONs.In this thesis,through an in-depth study and analysis of the literature both domestically and internationally,we show that existing RSA techniques,based on the objective function of minimizing the maximum subcarrier index,are difficult to use the spectrum resources of EONs effectively.To address this issue,we further refine the design of RSA problems by considering and leveraging the nature and characteristics of EONs.That enables us to propose a novel RSA scheme that minimizes the number of subcarrier allocations in the global network while ensuring the minimization of the maximum subcarrier index.A series of corresponding algorithms are developed,including integer linear programming formulations and greedy algorithms.Extensive experiments demonstrate that the proposed approach significantly improves the spectrum resource utilization and increases the fiber-optic transmission capacity of EONs.This thesis also provides new insights and research perspectives for RSA problems,laying a foundation for further improvements and optimizations in various other RSA problems related to EONs.