MGDM Technique for multiservice transmissionPresented By Tinu Ann Thomas Mtech Govt Model Engineering College Optoelectronics and Communication Roll no:15 Seminar Guide: Sudheer Babu P.P 1

TELECOMMUNICATION

Need for Communication is vital in human activities Facilitates transfer of knowledge Are prerequisite for economic growth

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Optical Fiber Communication

High speed Large bandwidth

Low cost Less prone to interference

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Why MMF is used?

Used in short range networks

Length of fiber should not exceed few kilometer

Size of the core More tolerance in the required alignment for coupling of light 4

Modes in an optical fiber

Light breaks down into separate modes inside the fiber The EM wave should satisfy boundary conditions Phase 2k Modes are transverse in nature TEm ,TMm 5

IN HOUSE NETWORKS

Fig1: A transparent MMF in-house network, integrating many different services.[2]

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MULTIPLEXING

Several conventional techniques exist for implementation of multiservice networks Widely used in telecommunication system Allows several users to access the same transmission medium Transmission resources are shared among users 7

MGDM TECHNIQUE

Multiplexing technique exploits unused capacity of of MMF

Similar to a MIMO radio system

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Fig2: A MGDM System[2] 9

Transmitter parameters

Set of exited modes depend on the launch conditions

Offset (F) Spot size (w)

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A 3X3 MGDM System

3 separate channels are created in GI-MMF By the injection of light at offsets F=0,13,26 m

Fig3:Three launched beams on the front facet of a GI-MMF, with radial offsets 0 m, 13 m and 26 m.[1]

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Fig4: Excitation prole and power distribution at the input facet of GIMMF (62.5/125) for three offsets with w=4 m.[1] 12

ReceiverAt reception every SGM has a specific area of optical energy at o/p of the fiber.

The o/p facet of the fiber is divided into N sections followed by the determination of light flux intensity area.

For the fundamental zone light energy is concentrated in the middle zone of the fiber.

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Fig.5 Light intensity distribution for three excitation Positions(F=0,13,26 m).[1]

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Fig6 :Three-segment detector geometry[2]

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Wireless MIMO link

[2] Fig7 : A wireless MIMO link.

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[1]

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Elements of the matrix present the subchannels yi N received signal si N emitted signal

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Classical MGDM system is based on equal optical power for all channels. Adapted for baseband transmission only Modification to this allows us to add radio services to the system.

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Modified MGDM Algorithm

[1]

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Power Criteria[1]

Receiver x captures a mix of signals. Reduce the overlap of radio signal I2 with before seperating the base band signals I1 Radio signal is considered as noise acting on the receiver x

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I2 P1

[1]

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Choice of optimal Transmitter Criteria

To protect the radio signal it is necessary to launch it on an optimal channel.

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Fig 8 Crosstalk i associated with each receiver (Ri) for a 4x4 system.[1]

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Fig 9 Emission with various average optical powers and wavelengths.[1]

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[1]

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Modified MGDM technique

Fig :10 :MGDM Model [1]27

ConclusionThe transmission of different services by a multimode fiber using the MGDM technique is effective in in-door networks. We viewed the possibility of using this technique for transmission of radio services with baseband services. The cost of the proposed solution is low 28 compared to WDM.

References[1]Adaptation of the mode group diversity technique for radio signal transmission over multimode fiber Optical Society of America Vol 3,NO 1/JANUARY OPT.COMMUN.NETW [2] Mode group diversity multiplexing in multimode fiber transmission systems by Christos Panagiotis Tsekrekos Faculty of Electrical Engineering of the Eindhoven University of Technology 2008 [3]Mode Group Diversity Multiplexing Transceiver Design for Graded-Index Multimode Fibres C.P. Tsekrekos, A. Martinez, F.M. Huijskens, A.M.J. Koonen COBRA research Institute, Eindhoven University of Technology [4]An Experimental Investigation of the Mode Group Diversity Multiplexing Technique,C. P. Tsekrekos, M. de Boer, A. Martinez, H. Kurniawan, F. M. J. Willems, A. M. J. Koonen Eindhoven University of Technology,2009 [5]Novel signal multiplexing methods for integration of services in in-buildings broadband multimode fiber networks Ton Koonen*, Henrie van den Boom, Anthony Ngoma, Laurens Bakker, Idelfonso Tafur Monroy, Giok-Djan Khoe* COBRA Institute, Eindhoven Univ. of Technology, The Netherlands [6]Recent developments in broadband service delivery techniques for short-range networks, Ton Koonen, Henrie van den Boom, Anthony Ngoma, Laurens Bakker, Idelfonso Tafur Monroy, GiokDjan Khoe COBRA Institute, Eindhoven Univ. of Technology 2008 [7]Optical fiber Communications by Gerd Keiser(second edition),GTE Communication system division [8]Optical fiber communication,by John M Senior 1985 Prentice Hall International Inc London

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THANK YOU

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