Ứng dụng kỹ thuật CDMA quang trong mạng chuyển mạch Burst quang

Mai Viet VUcfng, Dang The Ngoc<br /> <br /> <br /> Giii phip su dung ky thuit CDMA quang trong Trong mang ehuyen mach burst quang, eae burst<br /> xu ly tieu de cua mang chuyen mach burst quang dir lieu la mdt tap hpp cua nhieu gdi IP dupe ehuyen<br /> (OBSj la chu de dang duac nhieu ngudi quan tam. qua ede mit mang d dang todn quang. Thdng tin dieu<br /> Giii phip nay khong nhiing cho phep viec xu ly khien (tieu de) dupe tmyen tmdc burst du lieu vdi muc<br /> tieu de duac thuc hien hoin toin trong sudt tren dieh thiet lap ede ehuydn mach dpc theo dudng di eua<br /> mien quang ma cdn cai ttiien ding ke tde dd xu ly. burst. Burst dii Udu dupe tmyen theo sau gdi tidu de<br /> Vdi giai phip duac dd xuat, mang DBS se giii quyet md khdng can dpi xdc nhdn thiet ldp kdt ndi.<br /> duoc van de qua tii trdn matphing dieu ktiien. Tren mat phang dieu khidn, tidu de dupe xu ly<br /> trong mien didn dd Idy ra thdng tin dieu khien. Thdi<br /> 1. GIOI THIEU gian xu ly tidu de bao gom: Dinh dia ehi, tim kiem<br /> Su gia tang khdng ngimg eua luu lupng Intemet bang dinh tuyen, tao tidu de mdi. Ddy id mdt thdng<br /> bien nay vd su ldn manh nhanh chdng eiia cdc edng sd rat quan trpng lidn quan den hieu ndng lam vide<br /> nghd quang da tao ndn nhung bude ehuyen bien eua mang. Khi thdi gian xu ly ldn, ddn den tde dd<br /> mdi me trong kien tnic mang Intemet. Cdng nghe xu ly thdp, tde nghen de ddng xay ra do cde tidu de<br /> quang se ngay cang ldn manh hon nua vdi eae iing den md khdng dupe xu ly kip thdi.<br /> diing khdng chi ttong tmyen ddn ma cdn ed 6 phdn De tang toe dp xu ly tieu de, bai bdo dua ra giai<br /> ehuyen mach eiia mang Intemet quang the he ke phdp su dimg ky thudt da tmy nhap phdn chia theo<br /> tiep. Hidn tai, ed nhieu nghien ciiu dang tap tmng ma quang (OCDMA) [2] tten mat phang dieu khidn eua<br /> vao ba edng nghd ehuyen mach quang: Chuyen mang OBS de ndng cao hieu nang cua mang. Y tudng<br /> mach kdnh quang jOCS), ehuydn mach burst quang o day Id gdn tuong ung dia ehi cua mit dich ttong<br /> (OBS) vd ehuyen mach gdi quang (OPS). Trong dd, OBS tieu de vdi mdt nhan ma quang. Nhan nay dupe tao<br /> la mdt mang nghien ciiu khd hdp ddn bdi nd dupe ra va xu ly dua ttdn ky thudt OCDMA. Hoat ddng xu ly<br /> thiet ke de dat su cdn bang giiia ehuydn mach kenh nhan tai cdc mit dupe thue hidn ttong sudt ttdn mien<br /> vd ehuyen mach gdi, cd tinh mem deo, cho hieu ndng quang vd cho thdi gian xu ly nhd hon nhieu so vdi eae<br /> cao vd khdng edn ddn bd dem quang [1]. phuong phdp xu ly thdng tiiudng ttdn mien dien.<br /> <br /> <br /> <br /> 30 TAP CHI CNTT&TT KY 1 (8.2011)<br />  CONG NGHE VIEN THONG<br /> <br /> <br /> <br /> <br /> Wtbttniii<br /> vio<br /> <br /> <br /> <br /> Ulnkli<br /> OBS<br /> <br /> <br /> <br /> <br /> Nutbiinl6i<br /> ra<br /> <br /> Hinh 1: Ki&i tmc mang OBS dien hinh<br /> <br /> <br /> 2. MANG CHUYEN MACH BURST QUANG tinh bao mat thdng tin cao, don gidn hda vd phdn<br /> Hinh 1 thd hien mdt mang OBS dang ludi bao gdm edp kidm sodt mang ludi, ndng cao hidu qua su<br /> cde mit bidn vd cdc mit ldi [3]. Cde nut ehuydn mach dung pho tdn, khdng ydu edu cdc khoang thdi gian<br /> burst quang dupe kdt ndi bdi cde mydn WDM. Niit hay dai bdng tdn bao vd. Trong OCDMA, tin hidu eua<br /> OBS ehuydn mdt burst tii mit bidn ldi vdo tdi nut ngudi dimg khde nhau ed thd chdng ldn ldn nhau<br /> bidn ldi ra. Dua trdn thidt kd chuyen mach, nd cd ve ea mat thdi gian ldn tdn sd vd chia se cimg mdi<br /> thd ed hoac khdng dupe ttang bi bd dem quang. Cde tmdng tmydn dan chung. Da tmy nhap thuc hidn<br /> tuydn WDM mang td hpp nhidu bude sdng vd mdi bdng edeh gdn eho ngudi sii dimg khde nhau nhiing<br /> bude sdng eoi nhu mdt kdnh tmydn. Gdi dieu khidn ehudi ma phan biet nhu ttong Hinh 2.<br /> eua mdt burst ed the tmydn trdn eiing mdt kdnh vdi Nhiing img dung eo ban eua OCDMA bao gdm:<br /> burst dii lidu, hoac trdn mdt kdnh didu khidn ridng ghdp kdnh, ehuydn mach, tach/gbdp cdc tin hidu<br /> bidt. Mdt burst ed thd mang mdt bode nhidu gdi IP. da kdnh qua mang dudng true (backbone) vd mang<br /> vimg dd thi (MAN), dimg tridn khai mang da tmy<br /> 3. KY THUAT CDMA QUANG nhdp kdt ndi nhidu ngudi su dung qua mang ndi bd<br /> Ydu edu vd cdng nghd tmy nhdp quang hidn nay (LAN). Hon the niia, OCDMA dupe su dung dd xdy<br /> ddi hdi tmydn thdng tde dd cao vd luu lupng ldn, dung mang quang ddi xiing tdi bd gia dinh (FTTH)<br /> cho phep nhidu ngudi su diuig cimg chia se vimg vdi tde dp hang Gbps trong tuong lai.<br /> bdng thdng rdng ttdn midn quang. Hai hd thdng da Mdt sd nghidn eim gdn day eho thdy tidm nang<br /> tmy nhdp dang dupe su dimg phd bidn Id da tmy img dung OCDMA ttong tmy nhdp cua cde edng<br /> nhdp phdn chia theo thdi gian (TDMA) vd da tmy nghd mang mang tinh lal ghdp giiia quang vd vd<br /> nhdp phdn chia theo bude sdng (WDMA). Ben eanh tuydn, chang han nhu mang khdng day su dung<br /> hai hd thdng da tmy nhdp kd ttdn thi da tmy nhdp tmyen quang qua khdng gian (FSO) bode tmydn vd<br /> phdn chia theo ma quang (OCDMA) dang ngay edng mydn qua spi quang (ROF). Ngodi ra OCDMA edn<br /> nhdn dupe nhidu su ehii y vdi nhiing uu didm nhu<br /> <br /> <br /> TAP CHI CNTT&TT KY 1 (8.2011) 31<br />  CONG NGHE V I E N THONG<br /> <br /> <br /> <br /> <br /> BOOK song<br /> ttong lupng ma, bdng tdng sd chip ed gia tri 1; Xg, X^<br /> Nguoi s^dvogl<br /> tuong ling Id gid tri gidi ban eiia ham tu tiiong quan<br /> vd tuong quan chdo. Ham tu tuong quan va tuong<br /> quan chdo dae trung eho kha nang gay can nhidu<br /> ldn nhau giiia cde ehudi ma. Khi gid tri tu tuong<br /> quan cdng ldn vd gid tri tuong quan chdo edng nhd<br /> Thai gian thi kha nang phdn bidt hai ehuoi ma d ddu thu cdng<br /> NgBoi sv dpi^ 2 ldn hay ndi each khac ehiing edng it gay can nhidu<br /> ldn nhau.<br /> Bang 1: Anh xa giua dja chi c6ng vd chudi ma<br /> Hinh 2: Chia se tai nguySn dua trfin c6ng nghd CDIVIA<br /> Dia chi cong Ma<br /> dupe img dung trong mat phang didu khidn eua eae AI 01010101<br /> mang chuydn mach. A2 01011010<br /> <br /> Mdt vi du ve tao nhan dia chi tii ma OOC (L, w, X^,<br /> 4. MANG OBS SlT DUNG KY THUAT A-c) = (8,4,1,2) dupe minh hpa ttong Bang 1.<br /> CDMA QUANG<br /> Mdi ehudi ma ndi trdn se dupe ma hod vao eac xung<br /> Nhin Chung kidn tnic mang OBS su dung ky thudt<br /> quang vd tmydn di tten spi quang. Ky thudt OCDMA<br /> OCDMA hodn toan tuong tu nhu kidn tnic thdng<br /> ma hod pha thdi gian thuc hidn ma hod ehudi md<br /> thudng 6 Hinh I. Didm khde bidt 6 day la vide tao<br /> thdng qua bidn ddi vd pha cua xung quang, chang<br /> vd xu ly dia ehi nut dieh trdn mat phang dieu khidn<br /> ban xung quang cd pha la 0 se bidu thi gia tri 0,<br /> dupe dua trdn ly thuydt boat ddng cua he thdng<br /> xung quang ed pha la n bidu thi gid tri 1 trong ehudi<br /> OCDMA. Bdi vidt gidi thieu vd he thdng OCDMA ma<br /> ma. 6 vi du trdn, ma dia ehi dupe tmydn di Id hai<br /> boa pha thdi gian (TPC-OCDMA) [2]: Hoat ddng he<br /> ehudi xung vdi pha la: AT = {0, n, 0, n, 0, n, 0, n] vd<br /> thdng TPC-OCDMA, mdt kidn tnic nut ldi don gian<br /> A2' = {0, n. 0,71,7t, 0, jt, 0}. Ta gpi AI' vd A2' Id cdc<br /> eho phdp xu ly ede dia ehi dua trdn nhan ma quang<br /> nhan ma quang.<br /> vd md ta boat ddng eua nd.<br /> Kidn tiruc cua mdt he thdng TPC-OCDMA dd tao<br /> Tao nhan va xu* ly nhan<br /> ra nhan ma quang vd xu ly nhan dupe md td ttong<br /> Tieu dd chira dia ehi nut dich. De tao ra nhan ma Hinh 3.<br /> quang cdc dia chi ndy dupe dnh xa sang mdt ehudi<br /> Xung quang ddu vdo dupe chia nho ra 1dm L xung<br /> ede gid tri nhi phdn {0,1}. Cdc ehudi ndy dupe Idy tii<br /> quang, mdi xung dai didn cho mdi ctiipttongehuoi ma.<br /> mdt bd ma nhdt dinh. Trong he thdng OCDMA ede<br /> Dd bidu thi vi tri cde chip vd mat thai gian ede xung<br /> bd ma thudng dupe su dung la matirucgiao quang<br /> ndy dupe di qua cdc dudng ddy ttd quang vdi chidu<br /> (OOC), ehudi M....<br /> dai khde nhau. Sau cimg cdc xung ndy dupe dich pha<br /> Mdi gid tri {0,1} ttong ehudi dupe<br /> gpi la mdt chip. Chudi OOC dupe dac Bang 2: Anh xa giua chudi ma va nhan<br /> <br /> trung bdi bd tham so (L, w, Xg- ^c) Dia chi cong Ma Nhan<br /> ttong dd L la dp ddi ma, chinh bdng AI 01010101 {0,«-,0,;r,0,;r,0,;r}<br /> A2 01011010 {0,;r,0,;;r,;r.0,;r,0}<br /> tdng s6 chip ttong chudi, w gpi Id<br /> <br /> <br /> 3 2 I TAP CHI CNTT&TT KY 1 (8.2011)<br />  CONG NGHE V I E N THONG<br /> <br /> <br /> <br /> BOcflchpha<br /> Xung vdo<br /> OO^'O l>a\ Xungra<br /> <br /> <br /> <br /> <br /> BQ MA HOA<br /> <br /> <br /> <br /> Hinh 3: He thfingTPC-OCDIVIA<br /> <br /> tuong ling vdi vi tri eua chip la 0 hay I ttong ehudi ma. xung ddu ra bO gldl ma iing vdi cdng sudt (finh c6<br /> Ddu ra eua bd ma hod eho ta nhan ma quang, nhan thd diing 1dm tin hl$u md cdng chuydn m^ch trong<br /> ndy sau dd dupe tmydn qua mang. tmdng chuydn m^ch eua nut ldi, edng ndy dupe mo<br /> Tai phia thu, nhan dupe xu ly theo each ngupe lai, ehi cho phdp duy nhdt burst tuong img vdi nhdn di<br /> eae gia tri dieh pha dupe tinh todn sao cho sau hai qua. Y tudng ndy de xudt ra mdt md hinh xu ly tieu<br /> ldn dich pha (o bd ma hod vd bd gidi ma), pha eua dd dua ttdn nhdn ma quang tai nut ldi.<br /> tin hidu a mdi nhdnh Id nhu nhau: tp^j + tpjjj = tpj^^ Mo hinh xu* ly nhan tai nut loi<br /> + 9D2 ~ VE3 "'• *PD3^ — K®t qua 6 ddu ra bd giai ma<br /> Mdt md hinh xu ly nhan tai nut ldi dupe dd xudt<br /> se eho ra xung quang vdi edng suat dinh ndu nhan<br /> nhu Hinh 5. 6 ddy, dd don gian, ta chi xdt ddn qua<br /> ddu vao trimg khdp vdi ma eua bd giai ma, vi khi dd<br /> trinh xu ly dia chi nut dieh trong tidu dd dd Idy<br /> xung quang o eac nhdnh Id ddng pha nhau. Trong<br /> ra thdng tin dinh tuydn, vdn de xu ly cdc tmdng<br /> tmdng hpp ngupe lai nhan ddu vdo khdng khdp,<br /> khde trong tidu dd ta khdng xet ddn. Khdi xii ly<br /> xung quang trdn eae nhanh khdng ddng pha eho ta<br /> quang bao gom bd xii ly nhdn va tmdng chuydn<br /> xung quang tdng ed edng sudt rdt be. Hinh 4(b) vd<br /> mach N X N. Bd xu ly nhan gdm mdt bd chia cdng<br /> 4(e) minh hpa tin hidu ddu ra bd giai ma trong hai<br /> sudt quang 1 :n ndi den n bd 0ai ma. Cdc bd giai<br /> tmdng hpp nhan ddu vdo la AI' vd A2', o ddy phia<br /> ma ndy chira ma dia ehi eua ede nut dieh. Ddu vdo<br /> thu la bd giai ma eho dia ehi AI.<br /> cua bd xu ly nhan Id tidu de, ddu ra Id tin hidu<br /> Til boat ddng eiia he thdng trdn, ta nhdn thdy rang didu khidn mo cdng, tin hidu md cdng chi xudt<br /> <br /> Bi«nd9<br /> <br /> <br /> <br /> <br /> TMriglan Tlidrigian TMrigian<br /> <br /> (b) (C)<br /> Hinh 4: (a) Nhan quang ung vdi dja chi A I ,(b) Bau ra bO gidi ma khi ddu vao la A I ' ,<br /> (c) Ddu ra bO giai ma khi diu vao la A2'<br /> <br /> <br /> <br /> TAP CHI CNTT&TT KY 1 ( 8 . 2 0 1 1 ) 33<br />  CONG NGHE V I I N THONG<br /> <br /> <br /> <br /> <br /> BO gISi mS<br /> Tin h i ^ dileu Mvin #1<br /> <br /> <br /> <br /> <br /> J\6uab<br /> <br /> <br /> <br /> <br /> Cdngra#-|<br /> <br /> <br /> <br /> <br /> cdng vdo #n C6ng ra #1<br /> <br /> Hinh 5: M6 hinh xCr ly nhan tai nut lOi<br /> <br /> hien khi cd su trung khdp giua nhan va ma dia tao tin hieu md cdng. Chi duy rihdt mdt cdng dupe<br /> ehi nut dich. mo dd eho phdp burst di qua.<br /> Hoat ddng xu ly nhan nhu sau: Nhan ddu vdo dupe<br /> khudcb dai vd chia nhd thdnh cdc ban sao vdi sd 5. DANH GIA HIEU NANG<br /> lupng bang sd ma ttong ngdn hang dia ehi nut dieh, Dd ddnh gid bleu nang xu ly tieu dd khi su dung<br /> nhan sau dd dupe di qua dong thdi n bd giai md, nhan ma quang su dung md hinh bd xu ly nhan ehi<br /> mdi bd giai ehiia ma tuong img vdi mdt ma ttong ed bai bd giai ma, edu tao bd giai md gdm ede dudng<br /> ngdn hdng dia chi. Khi nhan ddu vdo trimg khdp vdi ddy tte quang vd bd dich pha, bd ma d ddy ed 8 chip<br /> ma dia ehi, se eho ra xung quang ed edng sudt dinh vd chu ky ctiip bdng 5 ps.<br /> o ddu ra bd giai ma, tin hidu ndy dupe su dung dd Thdi gian thuc giai md dupe tinh bang thdi gian<br /> 5ps<br /> B9 gidi ma<br /> <br /> Ti6ud6<br /> <br /> BO dich pha<br /> <br /> <br /> <br /> <br /> j LN#2 f-<br /> <br /> Hlnh 6: Mo hinh ddnh gia.<br /> <br /> <br /> <br /> 3 4 I TAP CHI CNTT&TT KY 1 (8.2011)<br />  CONG NGHE V I I N THONG<br /> <br /> <br /> <br /> <br /> Bang 3: So sanh cac md hinh xCr ly dja chi khac nhau<br /> <br /> Mo hinh xur ly Tdc do xnr ly (Hz) So lowng dia chi<br /> Phan mem 10* 10^ - 10*<br /> Logic duong day dien tu 10^ 10*-10"<br /> Bp nho dem 2x10'' 10^-10"<br /> Nhan ma quang IQW 10*<br /> <br /> dd bd 0ai ma nhdn du 8 chip. Vi ehu ky chip Id 5 ttdn midn quang ma vd mat tde dd xu ly cung dupe<br /> ps ndn thdi gian giai ma: r = (8 - l)x5 = 35 ps. edi thidn ddng kd. Bd dinh tuydn ldi vdi tde dd xu<br /> Tde dd xu ly nhan ehu ydu dupe quydt dinh bdi thdi ly cao se giai quydt dupe van de cpid tai ttdn mat<br /> gian giai ma [4], ndn duoc tinh mdt cdch tdng qudt phdng didu khidn.<br /> ^ 1 1 Mang OBS dupe xem la mdt bude chuydn tidp tii<br /> nhu sau: J ~Y~ (L-\)*hT ' ^ ' ' ^^'^S ^'° ^ ^^ ^° ^^^P<br /> mang chuydn mach kdnh quang ldn mang chuydn<br /> ttong mdt tii ma. AT la chu ky chip. Chdng ban Idy<br /> mach gdi quang vdi uu didm Id khdng edn su dimg<br /> sd lupng chip bang 32, chu ky chip bang 5 ps, khi<br /> bd ddm quang. Cdc nghidn eim ve OBS da dupe thue<br /> dy / = 6,5x 109 (Hz). V$.y sCt dimg nhan quang cd<br /> thS cho tdc dd xUlf ldn tdi-10 GHz. hien tir nhidu nam qua va vdn dang dupe tidp tue<br /> Bang 3 so sdnh mdt sd md hinh xii ly dia ehi theo day manh. Ap dimg xu ly nhan ma quangttdnmat<br /> hai tidu chi la vd thdi gian xir ly vd sd lugng dia chi phang dieu khidn eua OBS Id mdt phuong phdp mdi<br /> [5]. Day Id hai thdng sd quan trpng giup ddnh gid vd cho hidu qua cao, giiip gdp phan hodn thidn hon<br /> hidu ndng boat ddng eung nhu khd ndng md rdng nhiing nghien eim eiing nhu cdc giai phdp edi thidn<br /> eiia mang OBS. boat ddng cua mang OBSttongtuong lai.<br /> Ta ed thd thdy rang, edeh xu ly dia ehi thdng Tai lieu tham khao:<br /> <br /> tiiudng tdc dd xu ly bi ban chd do thdi gian xu ly [1]. YONGIVIEI SUN, TOMOHIRO HASHIGUCHI, VU QUANG<br /> <br /> bao gdm thdi gian kidm tra dia chi, tim Mdm bang IVIINH, XI WANG, HIROYUKI MORIKAWA, AND TOMONORI<br /> <br /> dinh mydn va tao dia ehi mdi. Tde dd xu ly dua trdn AOYAIVIA, "Design and implementation of 8^ optical bLTst-swiched<br /> <br /> hai md hinh la phdn mdm (10^ Hz) vd bd nhd ddm network testbed", IEEE Optical Communications, Nov. 2005.<br /> <br /> (2x10' Hz) Id khd cao nhung cho sd lupng dia chi [2]. HONGXI YIN, DAVID J. RICHARDSON, "Optical Code<br /> nhd, ttong khi dd sii dung logic dudng day didn tu Division Multiple Access Comnujnication Networks Theory and<br /> cho tde dd xu ly tiidp hon nhung tang dupe sd lupng Applications", Tslnghua University Press, 2007.<br /> dia chi. Vdi md hinh su dimg nhan ma quang eho ta [31. C. QIAO AND M.YOO, "Optical Burst Switching (OBS)- A<br /> tde dd xu ly Udu dd ldn tdi 10^° Hz vd sd lupng dia new paradigm fa an optical Intemet", Journal of high speed<br /> chi ldn (10'^ dia ehi). netw^aks, vol.8, no.l, pp. 69-84, Jan. 1999.<br /> <br /> [4]. N. WADA, H. SOTOBAYASHI, AND K. KITAYAMA "firor-<br /> 6 . KET L U A N<br /> free 100 km traismission of 10 Gbit/s optical code division<br /> Bdi bdo datirinhbdy mdt phuong phdp xu ly dia<br /> multiplexing using BPSK picoseconds-pulse code sequence with<br /> ehi mdi dua ttdn nhan ma quang eho mang OBS<br /> novel time-gating detection", Electron. Lett., vol. 35, pp. 8 3 3 —<br /> tiidng qua vide dp dung md hinh boat ddng eua ky<br /> 834, May 1999.<br /> tiiudt OCDMA, ma cu thd la ky thudt OCDMA ma hod<br /> [5]. KEN-ICHI KITAYAMA NAOYA WADA, "Photo IP routing",<br /> pha tiidi gian. Vdi phuong phap nay, khdng nhiing<br /> IEEE Photonics Technology Lett., vol. 1 1 , no. 12, Dec. 1999.<br /> qud tirinh xu ly dia chi dupe trong sudt hodn todn<br /> <br /> <br /> TAP CHI CNTT&TT KY 1 ( 8 . 2 0 1 1 ) 35<br />