A Novel Approach to Estimate and Analyse the FSO Link Margin for the Quality Based Network Routing

IJIRST –International Journal for Innovative Research in Science & Technology| Volume 4 | Issue 1 | June 2017 ISSN (online): 2349-6010

A Novel Approach to Estimate and Analyse the FSO Link Margin for the Quality based Network Routing Deeksha Sharma M. Tech. Student Department of Electronics & Communication Engineering Krishna Engineering College, UP, India

Poonam Goyal Assistant Professor Department of Electronics & Communication Engineering Krishna Engineering College, UP, India

Abstract The free space optics (FSO) communication is a growing up technology, which offers full duplex and usually protocol independent data transmission between two points. Distance between transmitting and receiving points can be from several meters up to a few kilometers. But FSO system has a large variation of receiving signal due to atmospheric phenomena. This fact limits the availability of FSO for a given transmission range, so it is very important to measure and know weather conditions such as fog parameters, humidity and temperature. To overcome the issue, in this paper, we are offering an approach which will help to increase link availability even for the worse conditions. We are also working on Blocking Probability estimation based on link margin which provides highest quality of transmission. Keywords: FSO, OOK, Modulation Assignment _______________________________________________________________________________________________________ I.

INTRODUCTION

In recent years, there has been substantial interest in studying the propagation of beams through turbulent atmosphere attributing to their importance in practical applications such as Free-Space Optical (FSO) communication [1-8]. It is well known that partially coherent beam is less influenced by turbulent atmosphere than completely coherent beam. Therefore, a considerable number of investigations have paid attention to the characterizations of partially coherent beam propagating through turbulent atmosphere. Finding a good method to improve the communication factors in FSO systems is an interesting topic which has attracted theoretical and experimental researches. One of the best methods in this regard is to use the combination of more than one laser beam as the source of the system that has been under intense research recently. Although a practical multi-beam FSO system normally uses up to four separate and distinct laser diodes that each one has its own collimator, but almost all of the related multi-laser papers have studied the propagation properties of laser arrays (located in one chip with a small separation) and just a little of them study multi laser beams. Although, most of the publications on this subject were devoted to the aberration-free case, almost aberration-free beam cannot be found. As it is well known, the aberrations may emerge while the laser beam passes through an optical system or turbulent atmosphere. Aberration may be sorted as Spherical, Coma, A disadvantage of FSO system has a large variation of receiving signal due to atmospheric phenomena. This fact limits the availability of FSO for a given transmission range, so it is very important to measure and know weather conditions such as fog parameters, humidity and temperature. FSO beams are absorbed and scattered by the air molecules as well as by the solid and liquid particles diffused in atmosphere. Absorption of the signal causes a decrease in signal strength. Scattering does not cause a decrease in signal strength, but it sends off the signal in different directions. The main emphasis of the research work is to increase the channel capacity, reliability and availability of Optical Free Space Links as important part of the „next generation” future network. With the current optical backhauls providing as high a data rate as 40Gbps, the end user is also looking for and demanding higher bandwidths to their personal computers or laptops. FSO is the technology to provide the end users with the data rates they can be satisfied with, at present, touching up to 1 Gbps. Free Space Optics, thus forms, a core component of the evolving optical broadband network and will prove to be a technology of high importance in the coming years, particularly in combination with RF-links in hybrid systems. II. LITERATURE REVIEW Matus Tatarko et al [2013] paper contains information about Free Space Optics (FSO) systems and their availability and reliability. FSO systems use infrared laser beams for optical communication between two static points and Line of Sight (LOS) technology is needed. Transmission media of optical signals is air, so weather has main influence on availability and reliability of FSO links. It is important to measure and statistically evaluate a quality of air in places, where the FSO system will operate. This article describes a device for measuring density of fog, relative humidity and temperature. From measured data, estimation of availability and reliability of FSO links in Slovakia is made.

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Fatemeh Dabbagh Kashani et al [2012] The propagation of aberrant flat-topped multi-beam passing through turbulent atmosphere is investigated based on the extended Huygens-Fresnel principle. The analytical expression for the cross-spectral density of this multi-beam propagating through the turbulent atmosphere is obtained. Power In Bucket (PIB), Signal to Noise Ratio (SNR) and Bite Error Rate (BER) are calculated numerically. The effects of the order of the flatness, aberration coefficient, wavelength, correlation length, separation distance and beam width on these link’s parameters are studied and analysed. The result is shown by some graphs. F. D. Kashani et al [2010] stated that the effects of auto-tracking subsystems on the bit- error-rate (BER) and reliability of freespace optical (FSO) communication links are investigated. Based on Gaussian beam formula on the receiver plane and considering the atmosphere losses due to absorption, scattering and atmospheric turbulence numerical values for Power In Bucket (PIB), Signal to Noise Ratio (SNR) and BER are calculated. Using above mentioned values, the role of auto-track subsystems on link reliability improvement is described. The results are illustrated by graphs obtained by calculation and simulation. M. Tatarko et al [2012] said that the work is focused on last mile system called FSO (Free Space Optics). Availability and reliability are estimated from measured fog parameters. In FSO system, the propagation media is air. The FSO systems working in free environment are very popular and establishing of connection is very easy. Erich Leitgeb et al [2005] expressed that worldwide, a lot of distributors offer optical free space links and in international research-co-operations Optical Wireless systems are investigated, developed and evaluated for manufacturers, telephone companies and providers. Optical links are projected and calculated in regard to range, bandwidth, traffic and weather (link budget, margin). The main emphasis of the research work is to increase the channel capacity, reliability and availability of Optical Free Space Links as important part of the „next generation” future network. III. PROBLEM FORMULATION The points mentioned below lead us to work further on our proposed approach:  The link reliability particularly in long range communication is limited mainly due to atmospheric turbulence-induced fading and sensitivity to weather conditions.  An FSO network with distance based routing and wavelength assignment (RWA) technique does not provide any information about the current state of network, leading to a non-reliable communication.  FSO provides a viable solution but the deployment of FSO link depends on different conditions. IV. PROBLEM DEFINITION      

To provide the Link availability even for the worse conditions. Blocking Probability estimation based on link margin. Provide highest quality of transmission. Availability of link for different atmospheric conditions in FSO. Wavelength assignment technique based on link margin. Deployment of an FSO network based on LM. V. OBJECTIVES

The objective of this research work is to estimate and Analyze the FSO link margin for the Quality based Network routing.  Modulation technique OOK is to be adopted.  RWA (Wavelength assignment) technique for better QOS. VI. METHODOLOGY            

Calculate Erlang B Calculate probable number of calls that are blocked Evaluate the number of recalls, considering a recall factor Calculate the new offered traffic Continue these steps in iteration until a stable value is attained Initialize the vertices for distance algorithm Fill the two trays with the distance and predecessor information initialize the graph All vertices have weight of infinity at the beginning but the weight of the source is zero. Link margin: initialize the light received calculate db where db= 10*log(margin(i,1)/lightReceived(i,1)); Plot the margin, light received and db.

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A Novel Approach to Estimate and Analyse the FSO Link Margin for the Quality based Network Routing (IJIRST/ Volume 4 / Issue 1/ 023)

VII. RESULTS AND DISCUSSIONS GUI of the Interface of our Proposed Method

Fig. 1: GUI of the interface of our proposed method

Blocking Probability

Fig. 2: Blocking Probability

Power Spectral Density of OOK

Fig. 3: Power spectral density of OOK

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A Novel Approach to Estimate and Analyse the FSO Link Margin for the Quality based Network Routing (IJIRST/ Volume 4 / Issue 1/ 023)

Bit Error Probability of OOK Modulation

Fig. 4: Bit error probability of OOK modulation

Shortest Path from Source Node to Destination

Fig. 5: Shortest path from source node to destination

Link Margin

Fig. 6: Link margin

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A Novel Approach to Estimate and Analyse the FSO Link Margin for the Quality based Network Routing (IJIRST/ Volume 4 / Issue 1/ 023)

Plot Distribution of OOK

Fig. 7: Plot distribution of OOK

VIII. CONCLUSION In our proposed approach, we estimated and Analyze the FSO link margin for the Quality based Network routing. The results we achieved are positive to what we proposed. These results will be helpful for researching any further study on FSO link margin. REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]

“Using Information about Weather Conditions to Define Availability and Reliability of FSO Links”, 23th Conference Radioelektronika 2013, April 16-17, Pardubice, Czech Republic “Reliability analysis of the Flat-topped multi-beam FSO communication link ”, 6'th International Symposium on Telecommunications (IST'2012) “Availability and Reliability of FSO links Estimation from Measured Fog Parameters”, MIPRO 2012, May 21-25,2012, Opatija, Croatia “Indirect Crosstalk-Aware Routing and Wavelength Assignment in Transparent Optical Networks with the Use of Genetic Algorithms ”, 2016 “A survey on physical layer impairments aware routing and wavelength assignment algorithm in transparent wavelength routed optical network”,MIPRO 2016, May 30 - June 3, 2016, Opatija, Croatia “The Minimum Cost Design of Transparent Optical Networks Combining Grooming, Routing, and Wavelength Assignment ”, IEEE/ACM TRANSACTIONS ON NETWORKING “A Novel Impairment Aware Routing and WavelengthAssignmentAlgorithmfor Optical WDM Networks”, 978-1-4799-6908-1/15/$31.00 ©2015 IEEE “Optimal Routing and Wavelength Assignment for Augmented Cubes in Linear Array Optical Networks ”, 978-1-4799 -1984-0 /15 / ©201 IEEE “Routing and Wavelength Assignment in a Satellite Optical Network Based on Ant Colony Optimization With the Small Window Strategy ”, VOL. 7, NO. 10/OCTOBER 2015/J. OPT. COMMUN. NETW. 995 “Dynamic Routing and Wavelength Assignment using Fuzzy Logic Controller in WDM Optical Networks ”, 978-1-4799-6761-2/15/ ©2015 IE X. Z, "On a dynamic wavelength assignment algorithm for wavelength-routed all optical networks," IET International Conference on Wireless, Mobile and Multimedia Networks, 2006, pp.1-4, 6-9 Nov. 2006. X. C. Bo Li, Z. Zhang, "A dynamic RWA algorithm in a wavelength-routed all-optical network with wavelength converters," IEEE INFOCOM 2003, vol. 3, pp. 1795- 1804 vol. 3, 30 Mar. 2003. B. Ramamurthy, D. Datta, H. Feng, J. P. Heritage, B. Mukherjee, "Impact of transmission impairments on the teletraffic performance of wavelength-routed optical networks," Journal of Lightwave Technology, vol.17, no.10, pp.1713-1723, Oct. 1999. H. Song, M. Brandt-Pearce, "Range of Influence of Physical Impairments in Wavelength-Division Multiplexed Systems," IEEE GLOBECOM 2011, 5-9 Dec. 2011. G. Zervas, and D. Simeonidou, “Cognitive optical networks: Need, requirements and architecture,” International Conference on Transparent Optical Networks (ICTON), 2010, pp. 1-4.

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A Novel Approach to Estimate and Analyse the FSO Link Margin for the Quality Based Network Routing

Published on Jan 12, 2018

IJIRST

The free space optics (FSO) communication is a growing up technology, which offers full duplex and usually protocol independent data transmission between two points. Distance between transmitting and receiving points can be from several meters up to a few kilometers. But FSO system has a large variation of receiving signal due to atmospheric phenomena. This fact limits the availability of FSO for a given transmission range, so it is very important to measure and know weather conditions such as fog parameters, humidity and temperature. To overcome the issue, in this paper, we are offering an approach which will help to increase link availability even for the worse conditions. We are also working on Blocking Probability estimation based on link margin which provides highest quality of transmission.