On the problem of minimizing the cost with optical devices in Wavelength Division Multiplexing optical networks: complexity analysis, mathematical formulation and improved heuristics

2019 ◽  
Vol 53 (5) ◽  
pp. 1513-1528
Author(s):  
Daniel Morais dos Reis ◽  
Natã Goulart ◽  
Thiago F. Noronha ◽  
Sérgio Ricardo de Souza

The Fiber Installation Problem (FIP) in Wavelength Division Multiplexing (WDM) optical networks consists in routing a set of lightpaths (all-optical connections) such that the cost of the optical devices necessary to operate the network is minimized. Each of these devices is worth hundreds of thousands of dollars. In consequence, any improvement in the lightpath routing may save millions of dollars for the network operator. All the works in the literature for solving this problem are based on greedy heuristics and genetic algorithms. No information is known on how good are the solutions provided by these heuristics compared to the optimal solution. Besides, no proof that the problem is NP-Hard can be found. In this paper, we prove that FIP is NP-Hard and also present an Integer Linear Programming (ILP) formulation for the problem. In addition, we propose an implementation of the Iterated Local Search (ILS) metaheuristic to solve large instances of the problem. Computational experiments carried out on 21 realistic instances showed that the CPLEX solver running with our ILP formulation was able to solve 11 out of the 21 instances to optimality in less than two minutes. These results also showed that the ILS heuristic has an average optimality gap of 1% on the instances for which the optimal solution is known. For the other instances, the results showed that the proposed heuristic outperforms the best heuristic in the literature by 7%.

2018 ◽  
Vol 7 (4) ◽  
pp. 6652
Author(s):  
N. Subhashini ◽  
A. Brintha Therese

With growing number of applications and network traffic, optic fibers are extensively used in the access part of the network. Passive Optical Networks (PON) in particular, Ethernet PON (EPON) networks based on Time Division Multiple Access (TDMA) are more prominently used in many parts of the world. Though Wavelength Division Multiplexing (WDM) PON has its own advantages, considering the cost and utilisation of such networks in the access part makes it less useful. On the other hand, Hybrid PON network combines the advantages of both EPON and WDM PON Networks. The objective of this paper is to identify suitable electrical filters for a 16-channel Hybrid Passive Optical Network with a transmission rate of 10Gbps per channel, by analysing their performance in terms of Q factor and Bit Error Rate. Different filters like the Bessel filter, Gaussian filter, Raised Cosine Filter, Rectangular filter, Butterworth filter, Chebyshev Filter are compared and their performances are evaluated. DB Modulation format that provides a longer reach is used at the transmitter to evaluate the different scenarios and the simulation is carried out using Optisystem.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bentahar Attaouia ◽  
Kandouci Malika ◽  
Ghouali Samir

AbstractThis work is focused to carry out the investigation of wavelength division multiplexing (WDM) approach on free space optical (FSO) transmission systems using Erbium Ytterbium Doped Waveguide Amplifier (EYDWA) integrated as post-or pre-amplifier for extending the reach to 30 Km for the cost-effective implementation of FSO system considering weather conditions. Furthermore, the performance of proposed FSO-wavelength division multiplexing (WDM) system is also evaluated on the effect of varying the FSO range and results are reported in terms of Q factor, BER, and eye diagrams. It has been found that, under clear rain the post-amplification was performed and was able to reach transmission distance over 27 Km, whereas, the FSO distance has been limited at 19.5 Km by using pre-amplification.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Fatma Mohammed Aref Mahmoud Houssien ◽  
Ahmed Nabih Zaki Rashed ◽  
Abd El-Naser A. Mohammed

AbstractThe 16-channels dense wavelength division multiplexing (DWDM) systems have been optimized by utilizing hybrid configurations of conventional optical fiber amplifiers (EDFA, RAMAN and SOA) and optical photodetectors (PIN, APD(Si) and APD(InGaAs)). The DWDM systems were implemented for 5 Gb/s channel speed using one of these configurations with 100 GHz channel spacing and 25 km amplifying section. The hybrid configurations are the combinations of (PIN + EDFA), (PIN + RAMAN), (PIN + SOA), (APD(Si) + EDFA), (APD(Si) + RAMAN), (APD(Si) + SOA), (APD(InGaAs) + EDFA), (APD(InGaAs) + RAMAN) and (APD(InGaAs) + SOA). Based on BER, Q-factor and eye diagrams, the performance was compared for these configurations under influences of various thermal noise levels of photodetectors over different fiber lengths ranging from 25 km up to 150 km. The results revealed that both APD structures give optimum performance at input power Pin = 5 dBm due to high internal avalanche gain. EDFA outperforms RAMAN and SOA amplifiers. SOA amplifier shows degraded performance because of nonlinearity effects induced. RAMAN amplifier seems to be the best alternative for long reach DWDM systems because it minimizes the effects of fiber nonlinearities. The configuration (APD(Si) + EDFA) is the most efficient and recommended to be used for transmission distance beyond 100 km due to its larger Q-factor.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Pinar Kirci ◽  
Abdul Halim Zaim

Optical technology gains extensive attention and ever increasing improvement because of the huge amount of network traffic caused by the growing number of internet users and their rising demands. However, with wavelength division multiplexing (WDM), it is easier to take the advantage of optical networks and optical burst switching (OBS) and to construct WDM networks with low delay rates and better data transparency these technologies are the best choices. Furthermore, multicasting in WDM is an urgent solution for bandwidth-intensive applications. In the paper, a new multicasting protocol with OBS is proposed. The protocol depends on a leaf initiated structure. The network is composed of source, ingress switches, intermediate switches, edge switches, and client nodes. The performance of the protocol is examined with Just Enough Time (JET) and Just In Time (JIT) reservation protocols. Also, the paper involves most of the recent advances about WDM multicasting in optical networks. WDM multicasting in optical networks is given as three common subtitles: Broadcast and-select networks, wavelength-routed networks, and OBS networks. Also, in the paper, multicast routing protocols are briefly summarized and optical burst switched WDM networks are investigated with the proposed multicast schemes.


Sign in / Sign up

Export Citation Format

Share Document