Design and analysis of wireless-optical broadband access networks (woban)

The growing customer demands for bandwidth-intensive services are accelerating the need to design an efficient "last mile" access network in a cost-effective manner. Traditional "Quad-play" applications (which refer to a bundle of services with voice, video, Internet, and wireless) and premium rich-media applications (e.g., multimedia, interactive gaming, and metaverse) need to be delivered over the access network to the end users in a satisfactory and economical way. Thus, besides its enormous transport capacity, today's access infrastructure should bring operational efficiencies, namely mobility and untethered convenience to end users. Hence, this dissertation proposes and investigates a novel hybrid network paradigm—wireless-optical broadband access network (WOBAN)—a combination technology of high-capacity optical access and untethered wireless access. This dissertation begins in Chapter 1 with an introduction to traditional broadband access networks—both optical and wireless networks, and compiles the research contributions and organization. Chapter 2 defines WOBAN, develops its architecture, and provides a comprehensive outline of its research aspects, coupled with various design models, and pros and cons of efficient protocols to manage the network. It also argues why the combination of optical and wireless technologies should provide an improved solution for future network design, and touches upon its current business drivers. Since both optical and wireless networks—two very diverse technologies—exist in a WOBAN, a trade-off is needed while designing the network. This means neither the optical nor the wireless part should be over- or under-provisioned to develop a cost-effective solution. Thus, Chapter 3 and Chapter 4 present design aspects of WOBAN in detail. While Chapter 3 focuses on heuristics— greedy algorithm and simulated annealing—to plan the network, Chapter 4 explores the constraint programming model, coupled with Lagrangean Relaxation, to achieve an optimal design solution. Once the network is deployed, efficient protocols need to be devised by exploring and exploiting WOBAN's novel aspects. Consequently, Chapter 5 examines the novelty of WOBAN's connectivity and develops a "Delay-Aware Routing Algorithm", called DARA. Unlike standard optical access networks, WOBAN poses a new challenge for streaming media applications due to its higher delay budget. Thus, DARA is an effort to minimize WOBAN's delay budget to deliver premium applications on-time. WOBAN, due to its hierarchical network architecture, can be subjected to multiple failure scenarios. Thus, minimizing the failures and restoring the network quickly, in case of failure, are important aspects to consider. Consequently, Chapter 6 develops a "Risk-and-Delay Aware Routing Algorithm" (an extension to DARA), called RADAR, to exploit the fault-tolerance behavior of WOBAN. Therefore, this dissertation creates new knowledge by introducing a novel network architecture for future access networks and makes important contributions by investigating design algorithms, network protocols, and business drivers behind the need for this converged network model, that is WOBAN.