Piotr Lechowicz

Piotr Lechowicz
Wroclaw University of Science and Technology | WUT · Department of Systems and Computer Networks

Ph.D.

About

35
Publications
5,966
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348
Citations
Introduction

Publications

Publications (35)
Article
Full-text available
Space division multiplexing (SDM) is a promising optical network solution with the scaling potential to overcome the possible capacity crunch problem in backbone networks. In SDM optical networks, optical signals are transmitted in parallel through spatial modes co-propagating in suitably designed optical fibers. The combination of SDM with wavelen...
Article
Full-text available
The volume of data traffic in backbone networks is increasing at a speed that exceeds the growth rates of capacities offered in currently used wavelength division multiplex-ing (WDM) networks. As a short term solution to the potential capacity crunch, the concept of flexible-grid elastic optical networks is nowadays implemented in many backbone net...
Article
This article identifies the unavoidably required upgrade of short-term realizable elastic optical networks (EONs) operating over single-mode fibers toward spectrally-spatially flexible optical networks (SS-FONs), exploiting spatial division multiplexing (SDM) technology in order to cope with the expected mid- and long-term future traffic forecasts....
Article
Spectrally-spatially flexible optical networks (SS-FONs) are seen as a next frontier in optical backbone networks that allow supplying demanded high-capacity transmission. In SS-FONs, signals are co-propagating in spatial modes of suitably designed optical fibers, e.g., in the bundles of single-core single-mode fibers. Despite significant fiber cap...
Article
Full-text available
Traffic in current networks is constantly increasing due to the growing popularity of various network services. The currently deployed backbone optical networks apply wavelength division multiplexing (WDM) techniques in single-core single-mode fibers (SMFs) to transmit the light. However, the capacity of SMFs is limited due to physical constraints,...
Chapter
Prior knowledge regarding approximated future traffic requirements allows adjusting suitable network parameters to improve the network’s performance. To this end, various analyses and traffic prediction methods assisted with machine learning techniques are developed. In this paper, we study on-line multiple time series prediction for traffic of var...
Article
Due to the continuous growth of Internet traffic, new technologies are proposed to overcome the capacity crunch problem. One of the most promising solutions for optical backbone networks is space division multiplexing (SDM), which allows parallel transmissions in properly designed optical fibers. In SDM, the problem of routing, space, and spectrum...
Chapter
Optical networks are vital communication infrastructure that supports services critical for the functioning of information society. The continuous growth of network traffic with tightening performance requirements combined with evolving physical-layer security threats poses multi-faceted challenges for network operators. To reduce network exposure...
Conference Paper
In this paper, we focus on the problem of resource allocation for time-varying traffic in translucent space-division multiplexing (SDM) elastic optical networks (EON) with back-to-back (B2B) signal regeneration. The performance is measured in terms of bandwidth blocking probability, usage of spectral resource (i.e. minimizing allocated bandwidth ov...
Conference Paper
In this paper, we motivate a brown-field migration planning as a cost-efficient procedure to scale the capacity of short-term realizable elastic optical networks (EONs), gradually converting them into spectrally-spatially flexible optical networks (SS-FONs). After a formal statement of the brown-field EON to SS-FON migration planning problem, a Sto...
Chapter
Spectrally-spatially flexible optical networks (SS-FONs) are proposed as a solution for future traffic requirements in optical backbone networks. As SS-FONs operate within flex-grid, the provisioning of lightpaths spanning multiple frequency slots results in spectrum fragmentation, especially in presence of dynamic traffic. Fragmentation, in turn,...
Conference Paper
We focus on spectrally-spatially flexible optical networks and analyze benefits of adjusting the number of active spatial modes in network links using various metrics based on data analytics with the goal to maximize the served traffic.
Conference Paper
Optimization of lightpath provisioning in a spectrally-spatially flexible optical network (SS-FON) is challenging due to many difficult constraints that exist in optical networks and because of limited amounts of various transmission resources (such as spectrum, spatial modes, transceivers, regeneration points). Previously demonstrated approaches u...
Conference Paper
Full-text available
Spectrally-spatially flexible optical networks (SS-FONs) are proposed as a solution to overcome the expected capacity crunch caused by the rapidly growing overall Internet traffic. SS-FONs combine two network technologies, namely, flex-grid optical networks and spatial division multiplexing yielding a significant capacity increase. Moreover, networ...
Conference Paper
Spectrally-spatially flexible optical networks (SS-FONs) are proposed as a solution for future traffic requirements in optical backbone networks. As SS-FONs operate within flex-grid, the provisioning of light-paths spanning multiple frequency slots results in spectrum fragmentation, especially in presence of dynamic traffic. Fragmentation, in turn,...
Conference Paper
We study inter-core crosstalk (ICXT) impact on migration planning toward spectrally-spatially flexible optical networks considering 22-core multi-core fiber. Results reveal, 55-70% of links need to be upgraded when ICXT ranges from -68.2 to-43.4 dB/km.
Article
Evolutionary methods are well-known tools used for solving hard computational problems. In this paper, we consider k¬-Shortest Steiner Trees (kSST) problem appearing in a diverse set of domains, e.g., multicast tree construction in communication networks in general, and optical networks in particular. The kSST is relatively new and has not been wid...
Conference Paper
We focus on a migration planning from elastic to spectrally-spatially flexible optical networks by upgrading regular with SDM-capable ROADMs. Our most promising strategy reveals that by migrating 30% of the regular ROADMs a 2x carried traffic increase can be achieved.
Conference Paper
In this article, we address the problem of survivable routing in spectrally-spatially flexible optical networks (SS-FONs) with dedicated path protection (DPP). The considered SS-FON supports spectral super-channel transmissions, in which flexible signal regeneration is realized with transceivers operating in back-to-back (B2B) configurations. We pr...
Conference Paper
In this paper, we consider spectrally-spatially flexible optical networks (SS-FONs) that combine the concept of space division multiplexing (SDM) and flexible-grid spectrally-flexible (elastic) optical networks (EONs). We assume that SS-FON uses spectral super-channel transmission, in which flexible signal regeneration is realized with transceivers...
Conference Paper
One of the most promising fibers for spatial division multiplexing (SDM) is weakly-coupled multi-core fiber (MCF). Despite significant capacity increase, MCFs suffer from physical layer impairments due to inter-core crosstalk (XT), which is the amount of signal leaking from adjacent cores. In this work, we focus on the impact of worst-case XT of MC...
Article
We focus on dynamic lightpath provisioning in translucent spectrally spatially flexible optical networks (SS-FONs) operating with multi-core fibers and realizing spectral super-channel transmission, in which flexible signal regeneration achieved with transceivers operating in back-to-back (B2B) configurations and modulation conversion is allowed. F...
Conference Paper
Full-text available
Space division multiplexing (SDM) is a promising optical network technology with the scaling potential to overcome the possible capacity crunch problem in backbone networks. SDM enables parallel transmission of several co-propagating spatial modes in suitably designed optical fibers, such as multi-core fibers (MCFs). The MCFs are prone to excessive...
Conference Paper
Full-text available
In this paper, we address the problem of routing, space and spectrum assignment (RSSA) in survivable flex-grid networks that implement spatial division multiplexing (SDM). In our consideration, we focus on two switching policies for the SDM (namely, independent and joint) while the network survivability is provided by dedicated path protection (DPP...
Conference Paper
Flexible-grid elastic optical networks (EONs) are expected to substitute in near future fixed-grid wavelength division multiplexing (WDM) optical networks. The previous works that were focused on optimization of EONs take many different assumptions regarding the transmission reach of modulation formats (MFs). However, according to the best of our k...
Conference Paper
Space division multiplexing (SDM) seems to be a promising solution with the scaling potential to overcome the possible capacity crunch problem in optical backbone networks. The main goal of this paper is to provide a detailed analysis of three SDM scenarios, namely, SDM-Fixed, SDM-Single, and SDM-Flexible in terms of the spectrum usage and the wast...
Conference Paper
Space division multiplexing (SDM) is a promising solution with the scaling potential to overcome the possible capacity crunch problem in optical backbone networks. The key idea behind SDM is to exploit the spatial dimension to provide a~significant increase in the transmission system capacity. In SDM, optical signals are transmitted in parallel thr...
Conference Paper
Due to continuously increasing popularity of various network services the overall Internet traffic grows quickly. According to the recent Visual Networking Index report published by Cisco, the IP traffic will grow at a compound annual growth rate (CAGR) of 22 percent from 2015 to 2020. Space division multiplexing (SDM) in optical networks seems to...
Conference Paper
Elastic Optical Network (EON) architecture has been proposed as a promising technology for a new generation of OFDM networks. It is based on the concept that spectrum can be split into smaller slices than are used currently in the fixed-grid network. It allows better spectral utilization and support for bit rates over 100 Gb/s. EONs arise with the...
Conference Paper
3d Printers create an object by printing thousands of successive thin layers. Each layer is created by the printing tool which moves on the selected paths. The ability to reduce the total length of printing paths results in lower overall time needed for printing process. In this paper there are presented two hybrid algorithms for that purpose, Gree...

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Projects

Projects (4)
Project
- traffic modeling - traffic prediction - traffic-aware network optimization and survivability provisioning
Project
This project is focused on optimization of multilayer application-aware networks. The key goal of the project is to develop, implement, and analyze models and algorithms for optimization of multilayer application-aware networks. An application-aware network can be defined as a network that is able to identify and classify applications and then use suitable optimization techniques to provision these application using resources accessible in the network in order to achieve acceptable application performance metrics. In turn, a multilayer network is a network modeled as a set of separate layers using various technologies and protocols applied to transmit data. In the context of this project, we assume that the network consists of two layers: packet layer and optical layer. The packet layer is used to directly serve the applications, i.e., to establish in the network demands required to serve various types of applications. In turn, the optical layer is used to establish virtual topologies to provision flows aggregated over the packet layer service demands. Project home page: https://www.kssk.pwr.edu.pl/projects/maan
Project
The main objective of the project is to develop, implement, and analyze models and algorithms for optimization of cognitive optical networks. In this project, we form a hypothesis that it is possible to develop new optimization methods in order to improve performance of optical networks by utilizing additional information provided by cognitive processes including data analytics mechanisms based on machine learning methods. Using the developed optimization models and methods, we plan to thoroughly examine in what extent and in which scenarios the concept of cognitive optical networks can improve the network performance comparing to conventional mechanisms currently used in optical networks.