Giulio Bottari

Bio: Giulio Bottari is an academic researcher from Ericsson. The author has contributed to research in topics: Optical performance monitoring & Node (networking). The author has an hindex of 17, co-authored 96 publications receiving 1149 citations.

Transmtting communications traffic across an optical communication network

Abstract: A method of transmitting communications traffic in an optical communication network comprising a plurality of nodes, the method comprising, at a source node: receiving communications traffic to be transmitted across the optical communication network to a target node; obtaining a path sequence defining an order in which a plurality of optical paths from the source node to the target node across the optical communication network are to be used, at least part of each optical path being spatially separate from each other optical path; and transmitting the communications traffic as a series of traffic portions, each traffic portion being transmitted for a respective preselected transmission period on a respective optical path according to the path sequence.

Modeling and Distributed Provisioning in 10–40–100-Gb/s Multirate Wavelength Switched Optical Networks

Abstract: In wavelength-switched optical networks (WSONs), quality of transmission (QoT) has to be guaranteed during lightpath provisioning. In multibit-rate WSONs, this task is complicated by the coexistence of optical connections operating at different bit-rates and modulation formats. The major issue consists in accounting for the severe impairments due to cross-phase modulation (XPM) induced by 10 Gb/s lightpaths on neighbor 40 or 100 Gb/s lightpaths. In this paper, QoT modeling is first reviewed for 10, 40, and 100 Gb/s transmission according to the adopted modulation format and detection type. In addition, a Gaussian approximation to compute the bit error rate of differential quadrature phase-shift keying (DQPSK) and QPSK signals is proposed, as well as closed formulas to compute the nonlinear phase noise variance due to XPM. Also, discussions about the XPM cumulation over spans in a WSON and how XPM can be considered in a dynamic network are provided. Then, four lightpath provisioning schemes are proposed to effectively account for QoT and, in particular, for XPM. The schemes differently exploit: 1) augmented spectral separation among lightpaths at different bit rates; 2) XPM worst-case scenario; and 3) current and novel generalized multiprotocol label switching extensions. The performance of the proposed schemes is evaluated through simulations in several multibit-rate scenarios. Results show that the proposed schemes provide effective network resource utilization while guaranteeing the adequate QoT to lightpaths at any bit rate.

Toward high-rate and flexible optical networks

Abstract: The evolution of optical technologies is driving the introduction of multirate optical networks exploiting advanced transmission techniques and efficient switching devices. In the short term, optical connections operating at 10 and 100 Gb/s will coexist in the same multi-rate network infrastructure. This, however, might introduce significant issues due to detrimental inter-channels effects, which need to be considered during network planning or connection provisioning. In the long term, connections at higher bit-rates (e.g., 400 Gb/s) and based on complex modulation formats (e.g., quadrature amplitude modulation - QAM) are expected, together with the adoption of innovative and flexible bandwidth-variable optical cross-connects (BV-OXCs). BV-OXCs have the potential to significantly improve the overall network spectrum efficiency. However, critical issues might arise in the dynamic control of network operations. This article discusses the enhancements required during operation and control of future optical networks with quality of transmission guaranteed. A first network evolution scenario is considered, where 100 Gb/s lightpaths are introduced in a native 10 Gb/s network. In such a scenario, inter-channel effects between 10 and 100 Gb/s lightpaths are highlighted. Relevant methods to account for these effects are discussed and evaluated. Then, a second network evolution scenario is assumed, in which traditional OXCs are replaced with BV-OXCs, and even higher bit-rates (e.g., 400 Gb/s 16-QAM) are introduced in the network. In particular, the problem of scalability when advertising and storing spectrum resource (i.e., frequency slices) availability is presented for flex-grid optical networks (i.e., optical networks exploiting BVOXCs). Consequently, a method to efficiently handle availability information is proposed and evaluated, showing the capability to overcome scalability issues without impacting the overall network resource utilization.

Rethinking Optical Transport to Pave the Way for 5G and the Networked Society

Abstract: The fifth generation of mobile networks (5G) is the next major phase of mobile telecommunications, which will provide the foundation for the Networked Society. To support 5G, transport will need to cater for a wide range of service requirements. It will need to support emerging 5G radio systems in terms of higher capacity and increasing number of cell sites. It must also cater for increasing need for radio interference coordination between sites as well as cost effective radio access network deployment models, and provide a flexible platform for sharing of resources where different actors through transport application programming interfaces have access to network resources and diverse transport services. In this paper, we summarize the key defining factors for 5G transport and outline a concept for programmable transport based on WDM and exploiting emerging optical devices enabled by integrated photonics.

Push-pull technique for defragmentation in flexible optical networks

Abstract: An efficient defragmentation technique based on optical channel re-tuning is proposed for flexible optical networks. Effective defragmentation with no traffic disruption is achieved without additional spare transponders or re-equalization operations.

Routing and Spectrum Allocation in Elastic Optical Networks: A Tutorial

Abstract: Flexgrid technology is now considered to be a promising solution for future high-speed network design. In this context, we need a tutorial that covers the key aspects of elastic optical networks. This tutorial paper starts with a brief introduction of the elastic optical network and its unique characteristics. The paper then moves to the architecture of the elastic optical network and its operation principle. To complete the discussion of network architecture, this paper focuses on the different node architectures, and compares their performance in terms of scalability and flexibility. Thereafter, this paper reviews and classifies routing and spectrum allocation (RSA) approaches including their pros and cons. Furthermore, various aspects, namely, fragmentation, modulation, quality-of-transmission, traffic grooming, survivability, energy saving, and networking cost related to RSA, are presented. Finally, the paper explores the experimental demonstrations that have tested the functionality of the elastic optical network, and follows that with the research challenges and open issues posed by flexible networks.

Dynamic Service Provisioning in Elastic Optical Networks With Hybrid Single-/Multi-Path Routing

Abstract: Empowered by the optical orthogonal frequency-division multiplexing (O-OFDM) technology, flexible online service provisioning can be realized with dynamic routing, modulation, and spectrum assignment (RMSA). In this paper, we propose several online service provisioning algorithms that incorporate dynamic RMSA with a hybrid single-/multi-path routing (HSMR) scheme. We investigate two types of HSMR schemes, namely HSMR using online path computation (HSMR-OPC) and HSMR using fixed path sets (HSMR-FPS). Moreover, for HSMR-FPS, we analyze several path selection policies to optimize the design. We evaluate the proposed algorithms with numerical simulations using a Poisson traffic model and two mesh network topologies. The simulation results have demonstrated that the proposed HSMR schemes can effectively reduce the bandwidth blocking probability (BBP) of dynamic RMSA, as compared to two benchmark algorithms that use single-path routing and split spectrum. Our simulation results suggest that HSMR-OPC can achieve the lowest BBP among all HSMR schemes. This is attributed to the fact that HSMR-OPC optimizes routing paths for each request on the fly with considerations of both bandwidth utilizations and lengths of links. Our simulation results also indicate that the HSMR-FPS scheme that use the largest slots-over-square-of-hops first path-selection policy obtains the lowest BBP among all HSMR-FPS schemes. We then investigate the proposed algorithms' impacts on other network performance metrics, including network throughput and network bandwidth fragmentation ratio. To the best of our knowledge, this is the first attempt to consider dynamic RMSA based on both online path computation and offline path computation with various path selection policies for multipath provisioning in O-OFDM networks.

Method and apparatus for coupling an antenna to a device

Abstract: Aspects of the subject disclosure may include, for example, receiving, by a feed point of a dielectric antenna, electromagnetic waves from a dielectric core coupled to the feed point without an electrical return path, where at least a portion of the dielectric antenna comprises a conductive surface, directing, by the feed point, the electromagnetic waves to a proximal portion of the dielectric antenna, and radiating, via an aperture of the dielectric antenna, a wireless signal responsive to the electromagnetic waves being received at the aperture. Other embodiments are disclosed.

Backhaul link for distributed antenna system

Abstract: A distributed antenna and backhaul system provide network connectivity for a small cell deployment. Rather than building new structures, and installing additional fiber and cable, embodiments described herein disclose using high-bandwidth, millimeter-wave communications and existing power line infrastructure. Above ground backhaul connections via power lines and line-of-sight millimeter-wave band signals as well as underground backhaul connections via buried electrical conduits can provide connectivity to the distributed base stations. An overhead millimeter-wave system can also be used to provide backhaul connectivity. Modules can be placed onto existing infrastructure, such as streetlights and utility poles, and the modules can contain base stations and antennas to transmit the millimeter-waves to and from other modules.

Remote distributed antenna system

Abstract: A distributed antenna system is provided that frequency shifts the output of one or more microcells to a 60 GHz or higher frequency range for transmission to a set of distributed antennas. The cellular band outputs of these microcell base station devices are used to modulate a 60 GHz (or higher) carrier wave, yielding a group of subcarriers on the 60 GHz carrier wave. This group will then be transmitted in the air via analog microwave RF unit, after which it can be repeated or radiated to the surrounding area. The repeaters amplify the signal and resend it on the air again toward the next repeater. In places where a microcell is required, the 60 GHz signal is shifted in frequency back to its original frequency (e.g., the 1.9 GHz cellular band) and radiated locally to nearby mobile devices.