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5G is finally here. Initial deployments are already operational in several major cities and first 5G-capable devices are being released. Though it is not limited only to millimeter wave deployments, the main promise of 5G lies in the utilization of the high bandwidth available at high frequencies. However, high-frequency deployments are coverage-limited and require denser placement of base stations, which can increase the cost significantly. One of the main contributing factors to the cost is fiber deployment. Integrated access backhauling (IAB), where part of the wireless spectrum is used for the backhaul connection of base stations instead of fiber, is an attractive solution that could make dense deployments economically viable. With this main objective, 3GPP is in the process of standardizing multi-hop IAB networks. This paper provides an overview of the main features of the multi-hop IAB 3GPP rel-16 standard and the rationale behind the design choices.

Energy-efficient optical networks are gaining momentum as environmental-friendly solutions with reduced operational costs. Energy-efficiency can be achieved by using devices in sleep mode, i.e., a low-power, inactive state in which devices can be suddenly waken-up upon occurrence of triggering events. This paper advocates a sleep mode option for the optical devices (e.g., amplifiers, optical switches) installed for protection purposes only. These devices can be put in sleep mode to reduce the network power consumption, but they can be promptly waken up (if necessary) upon a failure occurrence. This principle is proposed and applied in Wavelength Division Multiplexing (WDM) networks with dedicated-path protection to ensure survivability against single-link failures. The main contribution of the paper is the definition of the energy-efficient network planning problem for resilient WDM networks where optical devices can be configured in sleep mode. Optimal results of the integer linear programming (ILP) problem show savings of up to 25% in the overall power consumption.

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Elastic optical networks are envisaged as promising solutions to fulfill the diverse bandwidth requirements for the emerging heterogeneous network applications. To support flexible allocation of spectrum resources the optical network nodes need to be agile. Among the different proposed solutions for elastic nodes, the one based on architecture of demand (AoD) exhibits considerable flexibility against the other alternatives. The node modules in the case of AoD are not hard-wired, but can be connected/disconnected to any input/output port according to the requirements. Thus, each AoD node and the network (fabricated with AoD nodes) as a whole acts like an optical field-programmable gate array. This flexibility inherent in AoD can be exploited for different purposes, such as for cost-efficient and energy-efficient design of the networks. This study looks into the cost-efficient network planning issue for synthetic networks implemented through AoD nodes. The problem is formalized as an integer linear programming formulation for presenting the optimal solution. Furthermore, a scalable and effective heuristic algorithm is proposed for cost-efficient design, and its performance is compared with the optimal solution. The designed networks with AoD nodes are further investigated for a dynamic scenario, and their blocking probability due to limited switching resources in the nodes is examined. To alleviate the blocking performance for the dynamic case, an efficient synthesis strategy along with a scheme for optimal placement of switching resources within the network nodes is presented. Extensive results show that 1) even at high loads, the network with AoD nodes achieves saving of switching modules up to 40% compared to the one with static reconfigurable optical adddrop multiplexers (ROADMs) through a proper network design, 2) by diminishing the spectrum selective switches the overall power consumption of the network decreases by more than 25% for high loads, and 3) for the dynamic scenario the blocking owing to the node modules constraint is alleviated significantly by slightly augmenting the switching devices and optimally deploying them within the network nodes.

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The interest in the energy consumption of communication networks has risen in the recent years. In an effort to tackle this problem, several approaches have been presented to reduce the power consumed by the entire network infrastructure, including optical transport. Most of the solutions studied and proposed in the literature, however, pay little or no attention to the power consumed to ensure the resiliency of the overall network.In wavelength division multiplexing (WDM) networks resilient to single failures, an innovative strategy that can be adopted to reduce power consumption entails setting to sleep mode the optical devices supporting solely protection lightpaths. To take full advantage of this strategy, it is important to optimally route the lightpaths so that the number of devices supporting exclusively protection lightpaths is maximized. An optimal solution for this provisioning problem was previously presented, but features a limited scalability with the network size.This paper first proposes a scalable and efficient heuristic that chooses the route of the working and protection lightpaths with the aim to maximize the power saving. The performance of the heuristic is compared with the optimal solution and a sensitivity analysis of the drained power is carried out by considering a variety of networking scenarios. Up to 20% of the network links can be set to sleep leading to significant power saving, especially at low load and when the power consumption in sleep mode is negligible.