Passive optical networks (PONs) are currently evolving into next-generation PONs (NG-PONs) which aim at achieving higher data rates, wavelength channel counts, number of optical network units (ONUs), and extended coverage compared to their conventional counterparts. Due to the increased number of stages and ONUs, NG-PONs face significant challenges to provide the same level of survivability like conventional PONs without exceeding the budget constraints of cost-sensitive access networks. Toward this end, partial optical protection, in combination with interconnecting a subset of ONUs through a wireless mesh network (WMN) front-end, are promising solutions to render NG-PONs survivable in a cost-effective manner. In this paper, we present a probabilistic analysis of the survivability of NG-PONs and hybrid fiber-wireless (FiWi) access networks, taking both optical and wireless protection into account. In addition, we propose different selection schemes to wirelessly upgrade a subset of ONUs, and investigate their performance for a wide range of fiber link failure scenarios and different NG-PON topologies.

Survivability Analysis of Next-Generation Passive Optical Networks and Fiber-Wireless Access Networks

Hybrid fiber-wireless (FiWi) access networks aim at combining the huge amount of available bandwidth of optical networks and the ubiquity and mobility of wireless access networks with the objective to reduce their cost and complexity. This article highlights key enabling optical as well as wireless technologies and explains their role in emerging FiWi networks. After briefly reviewing previous art, important challenges and imperatives for the design of future FiWi network architectures, protocols, and algorithms are identified and discussed in detail.

Fiber-wireless (FiWi) access networks: Challenges and opportunities

The advent of Internet of Things and 5G applications renders the need for integration of both centralized cloud computing and emerging mobile-edge computing (MEC) with existing network infrastructures to enhance storage, processing, and caching capabilities in not only centralized but also distributed fashions for supporting both delay-tolerant and mission-critical applications This paper investigates performance gains of centralized cloud and MEC enabled integrated fiber-wireless (FiWi) access networks A novel unified resource management scheme incorporating both centralized cloud and MEC computation offloading activities into the underlying FiWi dynamic bandwidth allocation process is proposed Both MEC and cloud traffic are scheduled outside the transmission slot of FiWi traffic by leveraging time division multiple access An analytical framework is developed to model packet delay, response time efficiency, gain-offload overhead ratio, and communication-to-computation ratio for both cloud and broadband access traffic In addition, given the importance of reliability in optical backhaul and MEC, this paper develops a probabilistic survivability analysis model to assess the impact of both fiber cuts and MEC server failures The obtained results demonstrate the feasibility of implementing conventional cloud and MEC in FiWi access networks, without affecting network performance of broadband access traffic

Mobile-Edge Computing Versus Centralized Cloud Computing Over a Converged FiWi Access Network

A survey on access technologies for broadband optical and wireless networks

Survivability is one of the key issues in hybrid wireless-optical broadband access networks (WOBAN) since the single segment failure can cause huge data loss The single segment failure refers to a scenario where all optical-network-units (ONUs) are disconnected with the optical line terminal (OLT) Previous schemes focus on protecting WOBAN against single segment failure by deploying backup fibers However, previous schemes suffer from two key problems First, they ignore optimizing the selection of backup ONUs, which determines the cost of recovering the traffic interrupted by the failure Second, they underutilize the residual capacity of segments, thus requiring higher backup fibers cost In this paper, we propose a new and efficient scheme, called Optimizing Backup ONUs selection and backup Fibers deployment (OBOF), to enhance the survivability of WOBAN against the single segment failure Our OBOF is composed of two consecutive steps, backup ONUs selection and backup fibers deployment In the first step, aiming to minimize the cost of recovering the traffic interrupted by the failure, the simulated annealing (SA) algorithm is customized to optimize the selection of backup ONUs In the second step, most importantly, an enhanced greedy cost-efficiency (EGCE) algorithm is proposed to optimize the deployment of backup fibers Our EGCE consists of a novel remote backup segment (RBS) method, which can efficiently utilize the residual capacity of the segments, and a Bound on Length of Backup-optical-path (BLB) method, which limits the increase in recovery time induced by RBS Extensive experimental results demonstrate that our OBOF scheme outperforms the previous schemes significantly, especially in the scenario of higher traffic demand

Optimizing Backup Optical-Network-Units Selection and Backup Fibers Deployment in Survivable Hybrid Wireless-Optical Broadband Access Networks

The hybrid wireless-optical broadband access network is emerging as a promising technology to provide economical and scalable broadband Internet access. In this cross-domain network architecture, end users receive broadband services through a wireless, mesh front end that is connected to the optical backhaul through gateway nodes. In this article, we present the architecture and functional characteristics of a WOBAN prototype built in the Networks Lab at UC Davis. We discuss research challenges for hybrid networks based on our experimental observations.

S. Dixit

Papers

Hybrid wireless-optical broadband access network(woban) : prototype development and research challenges