Nguyen Trong Tam, Tran Manh Hung
Trong nhidu nam qua, nginh cdng nghidp viin thdng da khdng ngimg phit tridn vi cii tidn kidn tnic mang theo hudng thiic diy hdi tu vd tuydn, hOu tuydn, dd lidu vi cic dich vu video. Su ra ddi cua cdng nghd 4G/LTE cho phdp phit trien mdt mang toan IP vdi tdc dd vi bdng thdng ldn hon, nhdm hd trg vi cimg cip cic dich vu hdi tu mdi. Bed vidt 0di thidu chiic ning xu ly da phuong tidn nhu hd tro xuly da phuong tidn cho thoai qua LTE, trdn thoai, truydn nhac chudng nhac chd, hdi nghi truydn hinh vdi chia se video true tidp, trong mang 4G/LTE.
Nhiing dich vu niy dugc cung dp boi chirc ning tii nguydn da phuong tidn (MRF - Media Resource Function) trong kidn tnic IMS thdng qua cic miy chu da phuong tidn truydn thdng IP dugc thidt kd dS hd trg cic dich vu truydn thdng video vi thoai dua trdn gdi tin IP.
NHU CAU CHUYEN DOI MANG 3G LEN 4G/LTE
Nhu edu su dung video vd dft lieu di ddng dang bflng nd, theo du dodn cua Cisco luu lupng truy cap dft lidu di ddng todn edu se tang 26 ldn tu nam 2010 ddn 2015. Theo dd, den nam 2015 luu lupng video di ddng se chidm 66% tdng luu lupng dft lidu di ddng (Hinh 1), ehu ydu Id tfl dien thogi thdng minh, may tinh xdch tay va may tinh bang, chflng dang tidu thu mdt lupng bang thdng ldn vd ddn gay tdc nghen mgng, dan den su xudng cdp djch vu.
Theo khao sdt cua Cisco, didn tiiogi thdng minh, vi du mdt thidt bj iPhone hode Android se tgo ra luu lupng dft lidu nhidu hon 24 chide didn tiiogi di ddng ed tinh ndng co ban.
Su hdi tu eua mgng vien thdng vd IP, cflng vdi su tang trudng lidn tiic cua cac djch vu va flng dung ddi hdi nhidu bang thdng da thflc day nhu edu phdt
CONG NGHE V I I N THONG
20.9%
66.A%
2010 2011 2012 2013 2014 2015 Hinh 1: [>/b»^ luu lupng dCrli$u di dOng toan cdu ciJa Cisco, 2010 - 2015
tridn cdc tidu chudn, cdng nghd vd ndn tdng mdi.
Vd tidu chudn cdng nghd 4G/LTE ra ddi v0 mue tidu dap ling nhu cdu bdng thdng ngdy cdng tang, dac bidt ddi v0 cdc flng dimg nhgy cam vd tid nhu thogi vd video tnic tuydn. Bdn cgnh dd Id nhflng ling dimg da phuang tidn phong phfl vd cai tidn.
LTE cung cdp thdng lupng cao hon nhidu (vi du, gdp 4 ldn d dudng xudng vd gdn 8 ldn d dudng ldn) hon so VOT cdng nghd HSPA (Hinh 2).
Hon nfta, LTE edn ed nhidu uu didm khde nhu hidu suat mgng tdt hon, dd tid dupe cai thidn, ehl phi cho mdi GB dft lidu thdp ban, tiong khi phuc vu nhidu ngu0 dflng vai chdt lupng djch vu (QcS) tdt ban.
Tuy nhidn, bang thdng cao ban (4-8 ldn) tii LTE
350 300 250
5200
I Uplink Downlink
75
HSPA* LTE
Hinh 2: Thflng lupng dinh ciJa cac mgng di dOng 3G va 4G
cd thd vdn ehua du dd ddp flng nhu cdu phdt tridn cua thud bao (26 ldn vdo nam 2015), do dd cdc nhd mgng ndn dp dung ddng thdi nhftng 0dl phdp edn thidt khde dd 0dm bdt dp luc vd dung lupng mgng.
Vi du, ed thd cdt 0am muc tidu thu bang thdng bdng cdch chuydn tde dd vd ehuydn ma cac ludng video, mdt chflc ndng eua MRF tiong kidn trfle IMS.
PHAT T R I ^ N CAC D|CH V g D I DQNG TRONG 4 G / L T E
Vide ehuydn ddl mgng ldn 4GA.TE tgo ra nhidu co hdi cung cdp djch vu mdi cho thud bao cflng nhu tang doanh thu cho cdc nhd mgng. Ngodi ra 10 thd vd bang thdng ldn cdn m6 ra mOt canh cua mm cho
cac nhd cung cdp phdn mdm ddc ldp (ISV - Independent Sofware Vendor) phdt tridn thdm nhidu djch vu sdng tgo md hidn nay chua thd thuc hidn do su hgn chd bdng thdng cua cdc mgng 3G. Trdn ca sa dd, cdc nhd cung cdp djch vu cd tiid thidt ldp nhibig quan hd ddi tdc mm dd cung cdp nhidu nOi dung vd flng dimg phong phfl, nhdm mdf rdng md hinh kinh doanh bang rOng dl ddng.
Cdc mgng 4GA.TE VOT tdc dd nhanh va
CONG NGHE V I E N T H O N G
tP Strvicts Network (6G/LTE)
• Transcoding
• Transrating
• Media Conditioning
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Transcoding Inside MRF
3C SriMUphotw
PSTNPhont PSelt«hen*
on PC
Hinh 3: Chuydn ma trong IVIRF giup gl^m tinh phifc tap cua mang vS chi phi xCr ly da phuong ti6n trong kign true LTE IMS
hidu qua vd clii phi hon se hd tip mdt logt ede thiet bj tidu dflng (vi du, didn thogi thdng minh, mdy tinh xdch tay vd may tinh bang), kdt hpp vdi ede flng dung khdng ddy mdi nhu xe d td ket ndi, camera 0am sat va may mdc, mang lgi nhftng tiai nghidm vd kha nang tuydt vdi eho ngu0 su dimg. Cdc he
i ^ t ^
thdng dinh vj se eho phdp thud bao xem trudc cdc dia diem quan tam, hien thj quang cao hudng muc tidu tuy theo thdng tin cua nhung ngudi qua dudng.
He thdng kham chfla bdnh tu xa se thidt lap cac hdi nghi video true tuyen, an todn 0fta eae bac si va bdnh nhan theo thdi 0an thuc. Cdc kich ban nhu vgy ed the chuyen thanh ede co hdi doanh thu mdi cho cac nhd cung cdp dich vu, tiong dd su 0a tang cua cdc flng dimg may - may (M2M) dang tgo ra mdt dgng thidt bj dupe kdt ndi mdi can phai dupe quan ly vd hd tip qua Intemet
Cd the ndi tnmg tdm eua su hdi tu ndy la khdi tai nguydn da phuong tidn MRF. Nd ddng vai tid nhu bd ehuydn ddi cho nhidu logi thidt bj vd cdng nghd lidn quan, cho phdp chflng 0ao tidp vdi nhau mdt each hidu qua vd tin cay. V0 su phat trien va md rdng vd sd lupng vd su tia dgng eua cdc ma am thanh va video dupe su dung trong cae mgng vidn thdng hidn dgi, MRF thuc hidn chue ndng ehuydn ddi codec (chuyen ma), nhdm eho phdp nhieu logi thidt bj khdc nhau cd the chia se thdng tin. MRF edn 0flp ndng cao hidu ndng mgng, nd ma hda lgi ludng
CONG NGHE V I I N THONG
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Video v0 tde dd bit thdp hon, (hay edn gpi Id chuydn tde dd), md khdng ldm thay ddi ndi dung, de dd 0flp tidt kidm dang kd bang thdng. Vi du, chuydn ddi eae dogn video ed dd phdn 0di cao sang dd phan 0di thdp ban (tflc Id bang thdng thdp ban) phfl hpp cho tiiidt bj cdm tay ed mdn hinh nhd hoac bj 0di hgn vd bdng thdng nhdn. Vi vdy, ehuydn tde dd video, ehuydn md va can bdng ede ydu td tmydn thdng khde Id nhflng chflc ndng quan tipng dd tridn khai thanh cdng chidn lupc mdn hinh 3 trong 1 hd tip tivi, mdy tinh dd bdn vd cae tiiidt bj di ddng (Hinh 3).
MRF / M A Y CHU DA P H U Q N G T I | N I P
V0 kha ndng hd tip mflc dd hdi til da phuong tidn cao ban, cdc mgng tiid hd kd tidp phdn phdi dich vu qua nhidu phuong thue tmydn thdng:
thogi, fax, e-mail, tin nhdn tiie thin, web, hinh anh va video. Nhu vay, MRF sd kdt hpp tdt ea cdc kdnh tmydn thdng qua mdt mgng EP hidu qua vd ehi phi, tgo ra
nhflng phuong thue moi dd eung cdp nhflng djch vu vd tinh nang phong phfl m0, ma vdn 0am bdt dugc chi phi. Ddng th0, MRF cdn 0flp tdi uu hda ndi dung bang each chuydn md cdc ludng da phuong tidn, didu ehinh dung lupng ndi dung vd tde dd bit mdt cdch phfl hpp.
Vide chuyen ddi tii 3G ldn 4G/LTE dupe thue hidn
khdng qud phflc tgp, bdi ngay tii ddu MRF duge xdc djnh dd hd trg ede djch vu tmydn thdng gdi. Vi du, nhgc chd trong cdc mgng 3G duge eung cdp nhu Id mdt ludng dm thanh da phuang tidn chuydn mgch kdnh; v0 4G/LTE, mdt cudc gpi trdn ndn IP ydu cdu mdt 0ai didu nhgc chd dugc gui nhu mdt ludng da phuang tidn RTP. MRF tiiuc hidn cdc chflc ndng xu ly tgi mat phdng da phuang tidn, nhdm cho phdp kidm sodt bdi ede flng dung cua ngu0 dflng cudi.
Cdc phuang tidn tiruydn thdng MRF/mdy ehu da phuang tidn IP Id mdt thdnh phdn co ban tiong hg tdng djch vu dua tidn ndn IP, cho phdp xu ly vd tich hgp cdc ludng da phuang tidn video vd audio tiong
th0 0an thue cflng VOT du lidu vd fax. Vai tid ndy la ndn tang eho nhidu dich vu 0d tri 0a tang, bao gdm ea djch vu khach hang, trinh didn djch vu da phuang tidn. eae ling dimg 0am sat. bidu quydt tu xa khi xem tiruydn hinh dl ddng, vd didu khidn phdt ddl VOT ede ludng video (vi du nhu md, tgm diing...).
MRF TRONG K I E N TRUC 4 G / L T E
Trong cdc tidu chudn 3GPP, khdi tai nguydn da phuang tidn MRF dupc xdc dinh rd rang, dd eung cdp cae chue ndng xu ly da phuong tidn IP thOT, 0an thuc nhu phdt da phuong tidn, ghi, thu^pp
A ac
CONG NGHE V I E N THONG
GPRSCort J
ScrviCM In Picktt Data Natworfc
Hinh 4: Tich hgp mang tmy nh$p vo
chfl sd vd tidn dm thanh/vldeo dua vao eae ludng da phuang tidn IP. Ddi khi MRF dupe phdn chia thanh bd xu ly chue ndng tai nguyen da phuang tidn (MRFP - Media Resource Function Processor) cd vai tid ket cudi vd xir ly eae ludng da phuong tidn vd bd didu khien chflc ndng tai nguydn da phuang tidn (MRFC - Media Resource Function Contioller), lua chpn vd didu khien cdc MRFP. Trong dd 0ao didn Mb dupc dupc dflng de ehuydn tidp luu lupng kdnh mang tra MRF, hay cu the hon la MRFP. Luu lupng kdnh mang bao gdm khdi lupng ngdy cdng tdng eae gdi 0ao tiiuc thOT 0 a n thue (RTP), cflng VOT thdng tin RTCP tiong mat phang kdnh mang.
Trong mgng 4GA'TE, cdc ludng gdi tui Mb 0ao tidp tm cdng thdng tui gdi (PGW - Packet Gateway), nham eung cap ket ndi 0fta thidt bj nguOT dflng vd mgng dft lidu gdi bdn ngodi, quan ly chdt lupng djch vu (QoS) vd cung cap kidm sodt gdi sdu (DPI - deep packet inspection). PGW cflng thue hidn chue ndng djnh tuydn, cdp phdt cae dia ehi IP, eung cap tiruy cap ddi VOT ede mgng tmy cap khdng thude hp 3GPP vd thuc thi chinh sdch. Ddi VOT ede mgng eu hidn cd.
tuygn LTE vdilMS MRF
cdc ludng gdi tin Mb 0ao tiep vdi cdng da phuong tidn IMS (IMS-GW), chuyen ddi luu lugng sang dgng gdi (vi du nhu RTP) de tuong thich ngupc vdi cac kdnh chuyen mgch kdnh) (vi du. El).
MRF la mdt thdnh phdn quan tipng tiong IMS, ydu cdu su didu khien vd Mem seat bdi cdc yeu td khdc tiong Men trfle IMS, nhu cac may chu flng dimg hogc chue nang Mem soat tigng thai eude gpi (CSCF - Call State Contiol Function). SIP Id 0ao thue ehu ydu de dieu khien tiiidt bj MRF tiong Men tirflc IMS. Chue nang didu khien phidn cudc gpi phuc vu (S-CSCF - Serving Call Session Contiol Function) thuc hidn Mdm sodt phidn, didu khidn cudc gpi co ban vd thue thi ehinh sdch tiong IMS, tiong do su dimg 0ao didn Mr (SIP) dd didu khien cdc chflc ndng xu ly da phuang tidn MRF.
Khi cd ydu cdu vd mdt djch vu 0 a tri 0 a tdng (VAS), djch vu tang cudng, hoac xu ly eude gpi phuc tgp hon, cdc CSCF se ehuydn 0ao chflc nang dieu khien cudc gpi den mdt mdy chu flng dimg (AS), trong dd su; dimg 0ao didn (SIP) Mr* cflng VOT 0ao
g | CC CONG NGHE VI§N THONG
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didn Cr (ydu edu didu khidn da phuong tidn) dd Mdm sodt MRF nhdm tgo ra cdc djch vu mong mudn nhu nhgc chudng nhgc chd, tmydn cdc ludng da phuang tidn hoac hdi nghj da phuang tidn. Tdm lgi, didu khidn tiiidt bj MRF tiong mgng 4G/LTE todn IP dupc thuc hidn dua trdn 0ac thflc SEP vd 0ao didn Mr, Mr" vd Cr.
QUA T R I N H CHUYEN D 5 I TlT 3G LEN 4 G / L T E
Ndn tang cua mgng tiruy cdp vd tuydn LTE Id ldi gdi cdi tidn (EPC) (Hinh 4). Ngodi PGW vd PCRF, EPC cdn bao gdm cdng phuc vu (SGW) vd khdi qudn ly di ddng (MME). Trong dd SGW thuc hidn chue ndng djnh mydn vd ehuydn tidp ede gdi tin dfl lidu ngu0 dflng, ddng thdi hd tip chuydn 0ao 0fla cae eNodeB, cdn MME qudn ly cdc tigng thdi phidn, nhdn thue vd 0am sat ngu0 su dimg tidn mgng.
Thdng qua mdt mgng phdn tan thidt bj eNodeB - tuong tir nhu bd didu khidn mgng vd tuydn (RNC) tiong mgng 3G- cdc tiiidt bj tiruy nhdp va di ddng LTE khdc nhau dupe kdt ndi thdng qua mgng tmy nhap vd mydn LTE tOT EPC. Kha ndng tirong tiiich ngupc VOT cac mgng 3G va 2G dgt dupe thdng qua lidn kdt ndi VOT thidt bj node hd tip GPRS phuc vu (SGSN) tieng cdc mgng GPRS hidn ed. EPC se hd tip cdc djch vu khde nhau tipng mgng gdi dfl lidu cho cdc thud bao LTE, bao gdm cd IMS. Trong IMS, ede
thidt bj MRF sd phdn phdi qud trinh xu If da phuong tidn IP edn thidt cho ede djch vu vidn thdng LTE.
Giao didn ISC cung cdp kdt ndi bdo hidu 0fta PGW vd CSCF, phidn djch vd dua ra cdc ydu cdu xu ly da phuong tidn eho MRF bdng cdch su dung 0ao didn Mr. Giao didn Rx chia sd tiidng tin vd ehinh sdc tinh eude 0fta PCRF vd AS, sau dd thuc thi ehinh sdch thdng qua 0ao di$n didu khidn Mr t 0 MRF.
Do mgng ldi IMS vd MRF Id todn IP ndn vide chuydn ddi cdc mgng tiruy nhdp kdnh 3G Idn 4GAiTE dupc hd trp vdi MRF tiong Mdn trflc IMS. Thuc td, cdc mdy ehu da phuong tidn IP hidn nay sdn sdng hd tig phdn ldn ede ydu cdu MRF tiong tiidn khai LTE. Tuy nhidn, dd hd tig ddy du vide cung cdp dich vu thogi tiong mgng 4G ydu edu th0 0an tridn khai tirong ddi ddi, do dd qud trinh ehuydn ddi mgng ndn thiic hidn theo tflng 0ai dogn mdt.
Giai doan 1: Chi cung dp dc djch vu diili$u qua mang 4G/LTE
- Giflp logi bd nguydn nhdn chinh gdy tdc nghen tiong cdc mgng dft lidu 3G
- Don 0an hda vide tmydn vd chuydn ma da phuang tidn nhdm ndng cao chdt lugng tiai nghidm QoE.
- Tidp tflc hd tig cdc dich vu video vd thogi dupc tmydn qua mgng (vi du. Skype)
- Tdi uu hda cdc flng dung vd ludng ndi dung da phuang tidn qua mgng dft lidu di ddng LTE bdng
CONG NGHE V I E N THONG
each su; dung MRF
Giai doan 2: Hd trg cic dich vu thoai vi tin nhin SMS vdi CSFB (Circuit Switched Fall Back)
- Su tiling CSFB cho phdp tdi su dimg cdc tirung tam ehuydn mgch di ddng (MSC) vd co sd hg tdng
2G/3G eho ehuydn vflng, tinh cudc, djch vu khdn cap nhu 113, vd cdc dich vu thogi hidn cd. Didu ndy rdt quan tipng bdi vi cae tridn khai LTE ban ddu ed thd ed vflng phu sdng khdng lidn tue, do dd mdt sd dich vu didn thogi hidn cd ed thd ydu edu hd tip tfl CO so hg tdng 3G.
- Su dimg CSFB d6 hd tip cdc eude gpi thogi dua tidn LTE sang hg tdng ehuydn mgch kdnh hidn cd de hodn thdnh cudc gpi, dua tidn vflng phu sdng eua mgng LTE cflng nhu eho mdt sd ede djch vu nhdt dinh md chua ehuyen ddi sang eung cdp tidn mgng LTE.
Giai doan 3: Hd trg tit ca dc dich vu qua mang
4GAJTE, bao gdm thoai qua LTE (VoLTEj
- Dgt dupc tigng thai cudi cflng, tiong dd mgng
4G/LTE eung cdp vd hd trp ddy du ede djch vu tiiogi vd dft lidu.
- Cung cdp hd tip thdng qua MRF cho VoLTE, mdt sd djch vu thogi/video 0d tri 0a tdng cflng nhu cac djch vu mgng didn thogi thdng thudng theo djnh nghia eua MMTel.
- Cho phdp nha khai thac mgng tdi uu hda cdc tdi nguydn da phuong tidn dd cung cdp mdt tap da dgng cae flng dflng phan phdi ndi dung da phuang tidn sdng tgo thdng qua MRF.
Tai li^u t h a m khao
[1]. 3GPP TS 23.228 "Technical Specif cation Group Services and System Aspects; IP Multimedia SLt)system (IMS)"
[2]. www.mmtelforum.com and www.ericsson.com/res/docs/
whitepapers/mmtel .pdf
[3]. httpy/www.cisco.com/en/US/solutions/collateral/ns341/
ns525/ns537/ns705/ns827/whitejDaper_cll-520862.pdf [4]. www.radisys.com
[5]. www.nokiasiemensnetworks.com