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Dynamic Physical Impairment-Aware Routing
and Wavelength Assignment in 10/40/100 Gbps
Mixed Line Rate Optical Networks

Filippos BALASIS *, Xin WANG *, Sugang XU *, Yoshiaki TANAKA *, *** Global Information and Telecommunication Institute, Waseda University, Japan** Research Institute for Science and Engineering, Waseda University, Japanfbalasis@akane.waseda.jp, xinwang@ruri.waseda.jp, xusugang@m.ieice.org, ytanaka@waseda.jp

Abstract— The growing global Internet traffic will inevitably lead to a serious upgrade of the current optical networks' capacity.
Instead of upgrading the data rate of each wavelength in every fibre link across the entire optical WDM network infrastructure, it ismore efficient and cost-effective to support different data rates within one fibre link (e.g., 10, 40 and 100 Gbps). This is called optical
network with mixed line rates (MLR). Moving to higher than 10Gbps data rates that can be used within the same fibre requires theimplementation of phase modulation schemes. Nevertheless, the co-existing OOK channels cause a critical physical impairment to thephase modulated channels, namely cross-phase modulation (XPM), that limits the network's performance. In order to mitigate thistype of impairment a more sophisticated physical impairment aware routing and wavelength assignment scheme needs to be adopted.
In this paper, the critical impairment for each data rate and the way it affects quality of transmission (QoT) is presented. Secondly,
QoT aware RWA schemes for a MLR optical network are presented and evaluated in terms of performance through simulations.
Keywords—Mixed Line Rate, Optical Network, XPM, ASE, Physical Impairment, RWA
Filippos Balasis (B.E 2010) received his B.E. in electrical engineering and computer engineering from National Technical University ofAthens, Greece, in 2010. Currently, he is a Master student in Global Information and Telecommunication Studies, Waseda University,Tokyo, Japan. His study emphasizes on physical impairment aware RWA schemes in translucent WDM optical networks. After fulfilling
his military service he worked as an engineer in OTE, Greece's largest telecommunications provider, and he was part of the teamresponsible for the management and expansion of the company's access network. Mr. Balasis is a student member of IEICE.

Xin Wang (B.S. 2002–M.S. 2006) received the B.S. in computer science and engineering from Dalian University of Technology, Dalian,P.R.China, in 2002 and M.S. degree in computer science from Paris-sud 11 University, Paris, France, in 2006. Currently, he is a Ph.Dstudent in Global Information and Telecommunication Studies, Waseda University, Tokyo, Japan. His research interests focus on planningand control issue in wavelength switched optical networks. He received the IEICE ICM English Session Award and IEICE Young
Researcher’s Award in 2012. Mr. Wang is a student member of IEICE.

Sugang Xu (B.E. 1994–M.E. 1997–Ph.D. 2002) received his B.E. and M.E. degrees in computer engineering from Beijing Polytechnic
University, Beijing, China, in 1994 and 1997, respectively, and Ph.D. degree in information and communication engineering at theUniversity of Tokyo, Tokyo, Japan, in 2002. He joined the Global Information and Telecommunication Institute (GITI), Waseda
University in 2002, as a research associate. Since 2005, he joined National Institute of Information and Communications Technology(NICT), Japan, as an expert researcher. He is also a visiting researcher in GITI. His research interests include algorithms, networkarchitectures, photonic network control, optical grid network systems, parallel and distributed processing. Dr. Xu is a member of IEEE andIEICE.

2Yoshiaki Tanaka (B.E. 1974–M.E. 1976–Ph.D. 1979) received the B.E., M.E., and D.E. degrees in electrical engineering from theUniversity of Tokyo, Tokyo, Japan, in 1974, 1976, and 1979, respectively. He became a staff at the Department of ElectricalEngineering, the University of Tokyo, in 1979, and has been engaged in teaching and researching in the fields of telecommunication
networks, switching sys-tems, and network security. He was a guest professor at the Department of Communication Systems, Lund
Institute of Technology, Sweden, from 1986 to 1987. He was also a visiting researcher at the Institute for Posts and Telecommunications
Policy, from 1988 to 1991, and at the Institute for Monetary and Economic Studies, Bank of Japan, from 1994 to 1996. He is presently aprofessor at Global Information and Telecommunication Institute, Waseda University, and a visiting professor at National Institute ofInformatics. He received the IEEE Outstanding Student Award in 1977, the Niwa Memorial Prize in 1980, the IEICE Achievements
Award in 1980, the Okawa Publication Prize in 1994, the TAF Telecom System Technology Award in 1995 and in 2006, the IEICE
Information Network Research Award in 1996, in 2001, in 2004, and in 2006, the IEICE Communications Society Activity Testimonial in 1997 and in 1998, theIEICE Switching System Research Award in 2001, the IEICE Best Paper Award in 2005, the IEICE Network System Research Award in 2006 and in 2008, theIEICE Communications Society Activity Award in 2008, the Commendation by Minister for Internal Affairs and Communications in 2009, the APNOMS BestPaper Award in 2009, and in 2012, and the IEICE Distinguished Achievement and Contributions Award in 2013. Professor Tanaka is a Fellow of IEICE.