Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and                       Applications (IJER...
Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and                    Applications (IJERA) ...
Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and                    Applications (IJERA) ...
Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and                   Applications (IJERA) I...
Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and                                      App...
Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and                     Applications (IJERA)...
Upcoming SlideShare
Loading in …5
×

Ai25204209

183 views

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
183
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
4
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Ai25204209

  1. 1. Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.204-209 Performance Evaluation Of Ocdma Communication System Under The Effect Of Jitter Deepinder Singh1, Jagtar Singh2 1 Student, M.tech Electronics and Communication Section, YCOE, Talwandi Sabo, Guru Kashi Punjabi University Campus, Patiala 2 Associate Prof., Electronics and Communication Section, YCOE, Talwandi Sabo, Guru Kashi Punjabi University Campus, PatialaAbstract This paper focuses on the effect on BER, result, in the earlier years, the research on incoherentQ-Factor for a four user OCDMA communication OCDMA focused on looking for and obtainingsystem with varying Jitter. Performance of the unipolar codes with good auto-and cross-correlations,OCDMA communication system has been such as optical orthogonal/pseudo-orthogonal codesevaluated in terms of bit error rate and Q factor (OOC) [7], prime codes (PC) [6, 8], quadraticwith jitter varying from 0 pico-seconds to 3.0 pico- congruence codes (QCC), etc. Extended prime codesseconds in steps of 0.5 pico-seconds. Simulations (EPC) [9], modified prime codes (MPC) [10] andwere carried out using commercially available extended quadratic congruence codes (EQCC) [11]simulator from Rsoft, OPTSIM. have been proposed again In order to improve the performances of PC and QCC. OOC has the bestKey Terms: BER, Jitter, OCDMA, OPTSIM, Q- performance among these one-dimensional codes butFactor. its construction is complicated, compared with those of other codes. Even though one-dimensional OOC I. INTRODUCTION possesses the ideal auto- and cross correlations, and OCDMA is a technology which supports its cardinality, that is, the number of code words, ismultiple simultaneous transmissions in the same the largest, the number of users is inverselytimeslot and the same frequency to realize proportional to the data rate for single user in one-multiplexing transmission and multiple accesses by dimensional incoherent OCDMA systems becausecoding in the optical domain. Besides OTDM and the cardinality of codes is proportional to the lengthWDM and a potentially promising technique for of time-spread. While, the data rate for a single useroptical networks in the future, and especially, due to is inversely proportional to the length of the time-its easy access and flexible network structure, it is spread. In the meantime, the cardinality of code isvery applicable to the access network, it is another approximately inversely proportional to the square oftechnology of multiplexing and multiple accesses. To the code-weight. The smaller the code-weightverify the feasibility to implement incoherent becomes, the more the error probability increases. InOCDMA system by encoding in the time domain in order to meet the requirement of bit-error-rate, the1986, Prucnal, Santoro and Fan proposed to realize simultaneous number of active users in the networkthe fiber-optic LAN by using optical signal must be reduced. The application of one-dimensionalprocessing[5, 6], and used prime codes to carry out codes to incoherent OCDMA system is limited due tothe experiment of electronic encoding and fiber-optic the reasons mentioned above. Unipolar codes withdelay line decoding. In 1988, Weiner, Heritage and larger capacity need to be designed in order toSalehi [1] demonstrated how to spread the femto- increase the number of users. Therefore, startingsecond optical pulse into pico second-duration around 1990, researchers transferred their interestspseudo noise bursts. By encoding the light spectrum from the study on one-dimensional codes to 2Dinto pseudo random binary phase the spread OOCs [12-14], which enormously increases thefrequency was achieved and then by decoding the capacity of the system and improves thespectrum phase encoded to recover the original pulse. performance.The coherent ultra-short pulse coding and decodingcould be applied to the fast reconfigurable OCDMA II. JITTER AND ITS EFFECTScommunication networks was proposed by them. Transmitting and receiving a signal throughBoth breakthrough studies were milestones for the a medium or channel is the essence ofdevelopment of OCDMA. Optical encoding and communication. An early mathematical model fordecoding for incoherent OCDMA uses unipolar communication may be tracked back to Claudecodes whereas the bipolar codes used in radio Shannons famous 1948 [15]. Communicationfrequency code division multiple access (RF CDMA) systems are grouped into three basic categorieshave poor performance in OCDMA system and Depending on what kind of medium is used tocannot be used. Therefore, unipolar codes with good transmit and receive a signal: fiber, copper, andsystem performance need to be developed. As a wireless (or free space) . The bandwidths typically 204 | P a g e
  2. 2. Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.204-209are a few THz for fiber and a few GHZ for copper amplitude (ΔA) is defined as the amplitude noise (ormedia. Attenuation, and cost, fiber-based just noise), and the deviation of time (Δt) is definedcommunication is often used for long-distance (> 1 as the timing jitter (or just jitter). Though the impactskm), high-data-rate (up to > 100 Gb/s per channel) of timing jitter and amplitude noise are notcommunication, considering the constraints of symmetrical. Amplitude noise is a constant functionbandwidth.Copper-based communication is used for and can affect system performance all the time.medium-distance (< 1 km) and medium-high data Timing jitter affects system performance only whenrates (1 Mb/s to a few Gb/s per channel). Wireless is an edge transition exists. Any deviation from idealused for medium distance (~ km) and medium data waveform is defined as the Signal integrity generally.rates (up to ~100 Mb/s). The choice of a Signal integrity contains both amplitude noise andcommunication medium is largely determined by cost timing jitter in a broad sense. But, certain signaland application requirements. Fiber has the highest integrity signatures such as overshoot, undershoot,intrinsic bandwidth, so it can deliver the highest data and ringing may not be well covered by either noiserate possible for a single channel. or jitter alone.Fig.1 A Simple Communication System, IncludingThree Basic Building Blocks: Transmitter,Medium, And Receiver.[16] Fig. 3 Some Signal Integrity Key Signatures.[16] A physical process called noise is always The quality of a communication system isassociated with it when a signal is transmitted and affected by jitter, noise, and signal integrity. Thereceived. Noise is basically any undesired signals following sections discuss and illustrate how jitteradded to the ideal signal. The information is encoded and noise cause a bit error and under what conditionsin logical bits of 1 and 0 in the context of digital this bit error occurs. Then the metric that iscommunication. An ideal signal may be represented commonly used to quantify the bit error rate in aby a trapezoid wave with a finite 0 to 1 rise time or 1 communication system is discussed.to 0 fall time. In the presence of noise, it is the sum ofideal signal, with the noise giving rise to the "net" or III. SIMULATION OF FOUR USERactual signal waveform. The actual signal is identicalto the ideal signal waveform if no noise is added. As OCDMA SYSTEMshown in Figure2 the actual signal is deviated from Simulation set-up for four user OCDMA System hasthe ideal signal if the noise is added. been developed using Rsoft Optsim tool as shown in. Figure 4.Fig.2 An Ideal Signal Versus A Noisy Signal For ADigital Waveform.[16] From two aspects the deviation of a noisy Fig. 4 Block Diagram of Four User OCDMAsignal from its ideal can be viewed: timing deviation Networkand amplitude deviation. The amplitude of the digital Each user has a transmitter and a receiversignal for a copper-based system is the voltage, and and star network topology has been used. Starfor a fiber-based or radio frequency (RF) wireless coupler collects the power sent by the transmitterssystem it is the power. The deviation of the signal and distributes it equally among all receivers. 205 | P a g e
  3. 3. Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.204-209 IV. RESULTS AND DISCUSSIONS Table 1 : Variation of BER with Jitter for Different Fibers with Different Lengths Bit Error Rate (BER) J 10 Km 30 Km 50 Km 70 Km it t Co Luc Co Luc Co Luc Luc Cor e rni enta rni enta rni enta enta ning r ngl llaw ngl llaw ngl llaw llaw leaf ( eaf ave eaf ave eaf ave ave Fibe p Fib Fibe Fib Fibe Fib Fibe Fibe r s er r er r er r r ) 2.1 0.00 2.1 6.15 6.42 2.18 0 1E- E+0 1E- E- 0 0 E- E- 02 0 02 07 02 165 0 6.6 0.00 6.6 9.11 2.0 9.13 1.14 5.27 . 5E- E+0 5E- E- 3E- E- E- E- 5 03 0 03 03 04 03 02 03 1.1 8.52 1.1 1.95 8.2 2.54 1.06 1.01 1 0E- E- 0E- E- 2E- E- E- E- 02 76 02 02 04 02 02 02 1 1.2 3.00 1.2 3.63 8.3 2.87 1.02 6.80 . 3E- E- 3E- E- 9E- E- E- E-Fig. 5 Screen Shot of Four User OCDMA Network 5 02 88 02 02 03 02 02 03 4.3 5.80 4.3 1.93 9.0 9.65 1.11 1.06 2 4E- E- 4E- E- 4E- E- E- E- 03 111 03 02 03 03 02 04 2 3.4 6.95 3.4 1.06 7.6 4.79 9.50 3.11 . 7E- E- 7E- E- 3E- E- E- E- 5 02 126 02 03 04 02 03 03 1.7 1.09 1.7 7.76 4.1 2.89 1.29 8.88 3 1E- E- 1E- E- 5E- E- E- E- 02 29 02 03 04 03 03 03Fig. 6 OCDMA Code using three wavelengths ofλ1= 850 nm, λ2=1310 nm, λ3=1550 nm The construction of OCDMA code is shownin Figure 4.2. Simultaneous use of both time andwavelength results in 2-D coding space. The numberof wavelength channels used is denoted by Nw, whichis the number of rows used in the code. In eachwavelength channel, one bit period is divided into Lttime slots. Lt is the temporal length of the code sinceit indicates the number of chips available in a bitperiod per wavelength. The coding area D is theproduct of Nw and Lt, which also gives the totalnumber of available chips. The weight W of the codeis the number of chips in which a light pulse ispresent. These are called the 1 chips of the code. Thedensity of the code is the ratio of code weight tocoding area. Fig.7 Variation of BER with Jitter for L=10 Km 206 | P a g e
  4. 4. Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.204-209Fig.8 Variation of BER with Jitter for L=30 Km Fig.10 Variation of BER with Jitter for L=70 Km From Figures 7-10 and Table 1 as the value of Jitter is increased from 0 pico-second to 3.0 pico-second, the value of BER varies from 2.11E-02 to 1.71E-02 and 0 to 1.09E-29 for L = 10 Km, from 2.11E-02 to 1.71E-02 and 6.15E-07 to 7.76E-03 for L = 30 Km, varies from 0 to 4.15E-04 and 0 to 2.89E-03 for L = 50 Km and from 6.42E-02to 1.29E-03 and 2.18E-165 to 8.88E-03 for L = 70 Km for Corningleaf Fiber and Lucentallawave Fiber respectively.Fig.9 Variation of BER with Jitter for L=50 Km 207 | P a g e
  5. 5. Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.204-209 Q-Factor vs Jitter for L=10Km Q-Factor vs Jitter for L=50Km 1600 1600 Corningleaf Fiber Corningleaf Fiber 1400 Lucentallwave Fiber 1400 Lucentallwave Fiber 1200 1200 1000 1000 Q-Factor (dB) Q-Factor (dB) 800 800 600 600 400 400 200 200 0 0 0 1 2 3 4 0 1 2 3 4 Jitter (pico-second) Jitter (pico-second)Fig.11 Variation of Q-Factor with Jitter for L=10 Fig.13 Variation of Q-Factor with Jitter for L=50Km Km Q-Factor vs Jitter for L=30Km Q-Factor vs Jitter for L=70Km 6 30 Corningleaf Fiber Corningleaf Fiber Lucentallwave Fiber Lucentallwave Fiber 25 5 20 Q-Factor (dB) Q-Factor (dB) 4 15 3 10 2 5 0 1 0 1 2 3 4 0 1 2 3 4 Jitter (pico-second) Jitter (pico-second) Fig.14 Variation of Q-Factor with Jitter for L=70Fig.12 Variation of Q-Factor with Jitter for L=30 KmKm 208 | P a g e
  6. 6. Deepinder Singh, Jagtar Singh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.204-209From Figures 11-14 and Table 2 it can be Selected Areas in Communications, Vol.4,concluded that as the value of Jitter is increased from No. 9, 1986, pp1484 – 1494.0 pico-second to 3.0 pico-second, the value of Q- [7] H. Chung and P. Kumar: Optical orthogonalFactor varies from 2.03dB to 2.12 dB and 1.41E+03 codes—new bounds and an optimaldB to 1.13E+01 dB for fiber of L= 10 Km, from 2.03 construction. IEEE Trans. on InformationdB to -2.12 dB and 4.85 dB to 2.42 dB for fiber of L= theory, Vol.36, No.4, July 1990, pp866-87330 Km, from 1.41E+03dB to 3.34 dB and 1.36E+01 [8] A. S. Holmes and R. R. Syms: All-opticaldB to 1.36E+01dB for fiber of L= 50 Km and from CDMA using ―quasi-prime‖ codes.1.52 dB to 3.01 dB and 2.74E+01dB to 2.37 dB for IEEE/OSA Journal of Lightwavefiber of L= 70 Km for Corningleaf Fiber and Technology, Vol.10, No.2, Feb. 1992, pp279Lucentallawave Fiber respectively. Thus from – 286comparison of the overall performance of both the [9] G.-C. Yang and Wing. C. Kwong:fibers, it can be concluded that although in some Performance analysis of optical CDMA withcases Corningleaf Fiber show better results but prime codes. IEE Electronics Letters,overall Lucentallawave Fiber shows more consistent Vol.31, No.7, Mar. 1995, pp569 - 570performance. [10] Wing. C. Kwong, P. A. Perrier, and P. R. Prucnal: Performance comparison ofV. CONCLUSION asynchronous and synchronous code- With advantages like ability to increase the division multiple-access techniques fortransmission capacity of an optical fiber optical code fiber-optic local area networks. IEEE Trans.division multiple access (OCDMA) has been on Communications, Vol.39, No.11, Nov.recognized as one of the most important technologies 1991, pp1625 - 1634for supporting many simultaneous users in shared [11] S. V. Maric: New family of algebraicallymedia. Jitter is an important factor, which degrades designed optical orthogonal codes for use inthe overall performance of OCDMA system. In this CDMA fiber-optic networks. IEEpaper performance of the OCDMA communication Electronics Letters, Vol.29, No.6,system has been evaluated by jitter varying from 0 Feb./Mar./Apr. 1993, pp538 - 539pico-seconds to 3.0 pico-seconds in steps of 0.5 pico- [12] Sangin. Kim, Kyungsik Yu and Namkyooseconds. From simulation results it has been Park: A new family ofconcluded that although in some cases Corningleaf space/wavelength/time spread three-Fiber show better results but overall Lucentallawave dimensional optical code for OCDMAFiber shows more consistent performance. networks. IEEE/OSA Journal of Lightwave technology, vol.18, No.4, April 2000, pp502REFERENCES - 511 [1] Weiner, A. M., Heritage, J. P. and Salehi, J. [13] Raymond M. H. Yim, Jan Bajcsy and R. A.: Encoding and decoding of femtosecond Chen:A new family of 2-D wavelength-time pulse. Optics Letters, Vol.13, No.4, May codes for optical CDMA with differential 1988, pp300 – 302. detection. IEEE Photonics Technology [2] Castro, J.M. Geraghty D, ―Spectral phase Letters, Vol.15, No.1, Jan. 2003, pp165 - encoders for optical CDMA using anti- 167 symmetric‖ Optical Society of America, pp. [14] Naser G. Tarhuni, Timo O. Korhonen, 1214-1218, 2006 . Edward Mutafungwa, Mohammed S. [3] Denns T. et al., ―Demonstration of all Elmusrati: Multiclass Optical Orthogonal optical CDMA with bipolar code‖IEEE , Codes for Multiservice Optical CDMA 1997. Networks. IEEE/OSA Journal of Lightwave [4] Rosas J.B. et al., ―40 Gb/s Reconfigurable Technology, Vol.24, No.2, Feb. 2006, pp694 Optical CDMA Laser Encoder using Direct – 704 odulated Monolithic Mode-Locked [15] C. E. Shannon, "A Mathematical Theory of Lasers‖Optical Society of America, Communication," Bell System Technical pp.1102-1107, 2004. Journal, vol. 27, pp. 379–423, 623–656, [5] Prucnal, P. R., Santoro, M. A., Fan, T. R.: July, October, 1948. Spread Spectrum Fiber-optic Local Area [16] Mike Peng li, ‗Jitter, Noise, and Signal Network Using Optical Processing. Integrity at High- Speed‖ Prentice Hall, IEEE/OSA Journal of Lightwave ISBN-13: 978-0-13-242961-0, 2008. Technology, Vol.4, No.5, May 1986, pp547 - 554 [6] Prucnal, R. P, Santoro, M. A., Sehgal, S. K.: Ultrafast All-Optical Synchronous Multiple Access Fiber Networks. IEEE Journal on 209 | P a g e

×