Energy-efficient topology reconfiguration in green Fiber-Wireless (FiWi) access network

Abstract

As a promising access technique, Fiber-Wireless (FiWi) network not only enables the cost-effective broadband access, but also provides more opportunities for energy savings. Previous works mostly focused on energy savings in the optical back-end of FiWi. Generally, they extend the Optical Network Unit (ONU) sleep mechanisms initially designed for Passive Optical Network (PON) to FiWi by combining with the wireless rerouting. Most of these works, however, remain untouched energy savings in the wireless front-end. In fact, when one or more ONUs in the network is/are sleeping, many wireless components remain idle or underutilized which cause a lot of energy waste. In this paper, we propose a new energy-efficient Wireless-Optical Topology Reconfiguration (WOTR) scheme for the integrated energy savings in FiWi. Aiming to reduce energy consumption over the whole network, WOTR reconfigures the optical topology by using ONU sleep as well as the wireless topology by using Radio Interface (RI) standby. By means of topology reconfiguration, the network components will be utilized more efficiently, thus saving more energy. Simulation results show that WOTR can reduce the energy consumption significantly with just a little performance degradation in network throughput.

Advances in Improving Energy Efficiency of Fiber–Wireless Access Networks: A Comprehensive Overview

“…For the realization of joint EE improvement in both domains of the FiWi access network, another interactive PS method based on the wireless–optical topology reconfiguration (WOTR) technique is proposed in ref. [ 45 ] ( Table 1 ). The proposed reconfiguration scheme uses the ONU sleep method in combination with the method which puts the radio interface (RI) in the standby state.…”

“…Through simulations, the authors in ref. [ 45 ] demonstrated significant energy consumption reduction with negligible network throughput degradation when compared with optical-only PS schemes.…”

A Fault-Tolerant Transmission Scheme in SDN-Based Industrial IoT (IIoT) over Fiber-Wireless Networks

“…To address this issue, solutions were proposed to use “wake-up” strategies. A certain number of sleeping ONUs are deployed in the network and waken up only when some components break down [ 8 , 9 ]. However, because these backup ONUs do not work during normal communications, the resource utilization is still relatively low.…”

“…Few methods have been reported which can cover both sectors at the same time while considering the characteristics of industrial IoT scenarios. In wired networks, rerouting or presetting a backup path are common solutions [ 6 , 7 , 8 , 9 ]. Rerouting the interrupted traffic by finding a backup path with sufficient resources requires a long recovery time, which is not suitable for time-sensitive applications in the IIoT.…”

“…The sleeping nodes are only woken when some components break down. The interrupted traffic is resumed by using the backup nodes [ 8 , 9 ]. Although these methods can achieve survivability and reliability to some extent, their recovery time and resource utilization cannot meet the growing requirements of the IIoT.…”