68_thuyetminh

B THNG TIN V TRUYN THNG HC VIN CNG NGH BU CHNH VIN THNG

VIN KHOA HC K THUT BU IN

------- -------

THUYT MINH D THO QUY CHUN K THUT QUC GIA

V TN HIU TRUYN HNH S MT T (DVB-T2) TI IM THU TRONG VNG PH SNG

H NI, THNG 09-2012

MC LC

1. Tn gi v k hiu quy chun ............................................................................ 1 2. t vn ......................................................................................................... 1 2.1 Tnh hnh tiu chun ha................................................................................... 1 2.2 L do v mc ch xy dng tiu chun ............................................................ 9 2.3 Gii hn phm vi xy dng tiu chun .............................................................. 9 3. S c xy dng tiu chun................................................................................10 4. Ni dung chnh bn d tho quy chun.............................................................13 4.1 Tn ca quy chun ...........................................................................................13 4.2 B cc ca tiu chun ......................................................................................13 5. Tnh ton xy dng cc ch tiu k thut ..........................................................14 5.1 Di tn hot ng.............................................................................................14 5.2 di tn ..........................................................................................................14 5.3 Di thng ca tn hiu DVB-T2 .......................................................................15 5.4 T s li bit......................................................................................................15 5.5 T s sng mang trn tp m............................................................................15 5.6 Mc cng trng trung bnh ti thiu........................................................21

Thuyt minh d tho quy chun

Tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng Trang 1

1. Tn gi quy chun

Tn quy chun: Quy chun k thut quc gia v tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng.

2. t vn

2.1 Tnh hnh tiu chun ha

a) Tnh hnh tiu chun ha tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sngtrn th gii Hin nay cha c mt t chc chun ha no cng b cc yu cu i vi tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng, mt s khuyn ngh, tiu chun lin quan c th c ch ra nh sau:

T chc ITU

ITU c mt h cc khuyn ngh v tiu chun k thut i vi dch v truyn hnh qung b (ITU-R BT.xxxx). Gm mt s cc khuyn ngh chnh lin quan n truyn hnh nh sau:

ITU-R BT. 470: Conventional analogue television systems - Khuyn ngh ny cp n cc c tnh k thut c bn ca cc h truyn hnh tng t truyn thng.

ITU-R BT.1439: Measurement methods applicable in the analogue television studio and the overall analogue television systems - Khuyn ngh ny cp n cc phng php o cc h thng truyn hnh tng t.

ITU-R BT.1701: Characteristics of radiated signals of conventional analogue television systems - Khuyn ngh ny cp n cc c tnh ca cc tn hiu pht x trong cc h thng truyn hnh tng t truyn thng.

ITU-R SM. 329-10: Unwanted emissions in the spurious domain - Khuyn ngh ny cp n cc gii hn bc x gi cho nhiu loi thit b v dch v, trong c c dch v truyn hnh qung b.



ITU-R BT.601-4: "Encoding parameters of digital television for studios"- Khuyn ngh ny cp n cc tham s m ha truyn hnh s khi x l tn hiu ti cc phng dng hnh.

ITU-R P.1546: "Method for point-to-area predictions for terrestrial services in the frequency range 30Mhz to 3000Mhz" - Khuyn ngh ny cp n phng thc d bo ni suy cho cc dch v s trong

di tn 30Mhz n 3Ghz. ITU-R BT.419-3:

"Directivity and polarization discrimination of antennas in the reception of television broadcasting"- Khuyn ngh ny cp n cc c im hng tnh v phn cc anten thu ca dch v truyn fhnh s mt t.

ITU-R BT.1368-3/7: "Planning criteria for digital terrestrial television services in the VHF/UHF bands" - Khuyn ngh ny cp n phng php quy hoch cho cc dch v truyn hnh s mt t trong bng VHF/UHF.

ITU-R P.370-7: "VHF and UHF propagation curves for the frequency range from 20 to 1000 Mhz" - H khuyn ngh ny cp n c tuyn truyn sng bng tn VHF v UHF nm trong di tn s t 20Mhz n 1Ghz.

ITU-R BT.1735: "Methods for objective quality coverage assessment of digital terrestrial television broadcasting signals of System B specified in Recommendation ITU-R BT.1306"- Khuyn ngh ny cp n cc phng thc nh gi cht lng ph sng mt cch khch quan i

vi tn hiu truyn hnh s mt t thuc h B c xc nh ti khuyn ngh ITU-R BT.1306.

ITU-R BS.1283-1: "A guide to ITU-R Recommendations for subjective assessment of



sound quality" - Khuyn ngh ny cp n cc hng dn ca ITU trong vic nh gi ch quan cht lng m thanh.

ITU-R BT.798-1: "Digital television terresstrial broadcasting in the VHF/UHF bands" - H khuyn ngh ny cp n cc yu cu chung ca truyn hnh s mt t hot ng trong bng tn VHF/UHF.

ITU-R SM.328-9 : "Spectra and bandwidth of emisions" - Khuyn ngh ny cp n cc yu cu v ph tn v bng thng ca tn hiu bc x.

ITU-R SM.378-7: "Field-strength measurements at monitoring stations" - H khuyn ngh ny cp n cc yu cu v o cng trng tn hiu ti cc im/trm kim tra tn hiu.

ITU-R SM.443-2 : "Bandwidth measurement at monitoring stations" - H khuyn ngh ny cp n cc yu cu v o lng bng thng ti cc im/trm kim tra tn hiu.

ITU-R SM.1682 : "Methods for measurements on digital broadcasting signals"- Khuyn ngh ny ch dn cc phng php o tn hiu pht sng s.

ITU-R BT.2143-2: "Boundary coverageas sessment of digital terrestrial television broadcasting signals" - H khuyn ngh ny cp phng thc v ch tiu nh gi bin gii ph sng ca tn hiu truyn hnh s mt t.

ITU-R RRC6: "Final acts of the Regional Radiocommunication Conference for planning of the digital terrestrial broadcasting service in parts of Regions 1 and 3, in the frequency bands 174-230 MHz and 470-862 MHz" - Ti liu ny cp n cc chi tit c th v yu cu thc t i vi cc ch tiu k thut p dng trong quy hoch mng dch v truyn hnh s mt t trong bng tn 174-230Mhz v 470-862Mhz.

T chc IEC



IEC 62273-1: Methods of measurement for radio transmitter - Part 1: Performance characteristics of terrestrial digital television transmitters - Tiu chun ny khuyn ngh v cc ch tiu k thut ca my pht hnh s mt t DVB-T v phng php o nh gi.

IEC 60278-1: Cables distribution systems for television and sound signals and interactive services Part 1: System performance of forward paths (TA5) - Tiu chun ny khuyn ngh cc ch tiu k thut v phng php nh gi i vi h thng phn phi tn hiu truyn hnh cp v cc dch v tng tc, c cp cc ni dung lin quan n truyn hnh s mt t.

IEC 60244-1: Methods of measurement for radio transmitters Part 1: General characteristics for broadcast transmitters - Tiu chun ny khuyn ngh cc c tnh chung ca cc my pht v tuyn qung b v tiu chun ho iu kin cng nh phng php o c s dng nh gi cht lng ca mt my pht vo otuyn qung b.

IEC 60244-5: Methods of measurement for radio transmitters Part 5: Performance characteristics of television transmitters - Tiu chun ny khuyn ngh cc phng php o nh gi c tnh cht lng ca cc my pht

hnh. Tiu chun ny a ra cc iu kin o chung, v phng php o cc c tnh lin quan n tn hiu hnh.

IEC 60244-10: Methods of measurement for radio transmitters Part 10: Methods of measurement for television transmitters and tranposers employing insertion test signals - Tiu chun ny l mt trong h cc tiu chun IEC 60244, khuyn ngh cc phng php o my pht v tuyn, m t



cc phng php o khuyn ngh p dng nh gi cht lng ca

cc my pht v tuyn. Tiu chun ny p dng cho cc my pht hnh hot ng ph hp vi cc h thng truyn hnh. Cc phng php o trong tiu chun rt hu ch trong vic kim tra cht lng ca my pht khi ang pht chng trnh.

IEC 62216-1: "Methods of measurement for the DVB-T system - Part 1: Baseline receiver specification" - Tiu chun ny khuyn ngh cc phng php o, nh gi cc c tnh k thut c bn ca my thu DVB-T.

IEC 62002-1: "Mobile and portable DVB-T/H radio access - Part 1: Interface specification" - Tiu chun ny khuyn ngh cc c im v giao din truy nhp dch v truyn hnh s mt t trong iu kin di ng v lu ng.

IEC 62002-2: ""Mobile and portable DVB-T/H radio access - Part 2: Interface conformance testing" - Tiu chun ny khuyn ngh cc php kim tra s thch ng ca giao din truy nhp dch v truyn hnh s mt t trong iu kin do ng v lu ng..

T chc ETSI

ETSI EN 300744: Digital Video Broadcasting (DVB) - Framing structure, channel coding and modulation for digital terrestrial television- Ti liu tiu chun ny khuyn ngh c t cu trc khung, iu ch v m ha knh cho truyn hnh s mt t s dng cng ngh DVB-T.

ETSI ETR 154: Digital Video Broadcasting (DVB) - Implementation Guidelines for



the Use of MPEG-2 Systems, Video and Audio in Satellite, Cable and Terrestrial Broadcasting Applications- Ti liu tiu chun ny khuyn ngh cc hng dn p dng cc h thng nn hnh nh MPEG-2, hnh nh v m thanh trong h thng truyn hnh v tinh, cp v cc ng dng trong truyn hnh s mt t.

ETSI ETR 211: Digital Video Broadcasting (DVB) - Guidelines on Implementation and Usage of Service Information (SI)- Ti liu tiu chun ny khuyn ngh cc c t m ha cc thng tin dch v trong h thng truyn hnh s DVB.

ETSI EN 301 958: Digital Video Broadcasting (DVB) - Interaction Channel for Digital Terrestrial Television (RCT) Incorporating Multiple Access OFDM- Ti liu tiuchun ny khuyn ngh cc c t v c tnh c bn ca knh truyn hnh tng tc cho h thng phn phi tn hiu truyn hnh s mt t s dng tiu chun DVB-T ph hp ti liu tiu chun ETSI EN 300 744.

ETSI TS 102 005: Digital Video Broadcasting (DVB) - Specification for the use of video and audio coding in DVB services delivered directly over IP- Ti liu tiu chun ny khuyn ngh cc c t phng php m ha hnh nh v m thanh ca cc dch v c truyn dn qua giao thc internet (IP).

ETSI TR 101 190:Digital Video Broadcasting (DVB) - Implementation Guidelines for DVB Terrestrial Services; Transmission Aspects - Ti liu tiu chun ny khuyn ngh cc c t v cc dch v trong h thng truyn



hnh s mt t s dng cng ngh DVB-T v m t chung v cu hnh mng n tn v a tn trong h thng truyn hnh s mt t DVB-T.

ETSI TR 101 290: Digital Video Broadcasting (DVB) - Measurement guidelines for DVB systems - Ti liu tiu chun ny khuyn ngh cc ch dn v o lng v phng php o nh gi cht lng h thng truyn hnh s DVB.

ETSI EN 302 755: Digital Video Broadcasting (DVB) - Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2) - Ti liu tiu chun ny khuyn ngh cc c t v cu trc khung, m ha knh v iu ch cho truyn hnh s mt t th h 2.

ETSI TS 102773: Modulator Interface (T2-MI) for a second generation digital terrestrial television broadcasting system (DVB-T2) - Tiu chun v thng s k thut Giao din iu ch cho h thng truyn hnh s th h th hai.

ETSI TS 102 831 (08/2012): Digital Video Broadcasting (DVB); Implementation guidelines for a second generation digital terrestrial television broadcasting system (DVB-T2)- Truyn hnh s (DVB);Cc hng dn thc hin cho h thng truyn hnh s mt t th h th hai (DVB-T2)

ETSI EN 302 296: Electromagnetic compatibility and Radio spectrum Matters (ERM); Transmitting equipment for the digital television broadcast service,



Terrestrial (DVB-T); Harmonized EN under article 3.2 of the R&TTE Directive -Ti liu tiu chun ny khuyn ngh cc c t v tng thch in t v ph tn, cc thit b truyn dn cho dch v truyn hnh s.

ETSI EN 302 297: Electromagnetic compatibility and Radio spectrum Matters (ERM); Transmitting equipment for the analouge television broadcast service; Harmonized EN under article 3.2 of the R&TTE Directive -Ti liu tiu chun ny khuyn ngh cc c t v tng thch in t v ph tn; cc thit b truyn dn cho dch v truyn hnh tng t.

T chc NoDig

T chc Nordig gm i din ca 5 nc v 3 qun o thuc khu vc Bc u hp tc xy dng cc quy nh v truyn hnh s ni chung v thit b thu truyn hnh s ni ring:

NorDig Unified Test Specifications: for SD and HD Level - Integrated Receiver Decoders for use in cable, satellite, terrestrial and IP-based networks - B ti liu m t cc c im kim tra i vi cc thit b thu gii m tch hp dng cho cc mng truyn hnh s mt t, v tinh, cp v IP.

NorDig Unified Requirements: for profiles - Basic TV, Enhanced, Interactive and Internet for Digital Integrated Receiver Decoders for use in cable, satellite, terrestrial and IP-based networks - B ti liu ny quy nh cc yu cu v tp thng s c s cho TV, dch v nng cao, dch v tng tc v internet i vi my thu gii m truyn hnh s s dng trn mng cp, v tinh, mt t v mng IP.

b) Tnh hnh tiu chun ha v tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng Vit Nam



Hin ti B Thng tin Truyn thng cha c mt quy chun no quy nh v cht lng tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng p dng.

Nhn xt:

Cn thit a ra mt quy chun quy nh cc ch tiu i vi tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sngnhm gip cc C quan qun l nh nc v cc doanh nghip cung cp dch v thc hin qun l cht lng dch v truyn hnh s mt t (DVB-T2) mt cch thng nht, ng thi cng l c s ngi s dngv doanh nghip cung cp dch vgim st cht lng dch v truyn hnh s mt t (DVB-T2) khi cng ngh ny c trin khai p dng.

2.2 L do v mc ch xy dng tiu chun

Cng ngh truyn hnh s mt t theo chun DVB-T2 c nghin cu, th nghim v trin khai rng ri cho thy nhng u im ni bt so vi DVB-T v c cho l bc pht trin tip theo ca DVB-T. Hin ti, DVB-T2 c mt s nh cung cp dch v s dng ti Vit Nam, tuy nhin cha c mt tiu chun quc gia nhm nh gi cht lng tn ca truyn hnh theo chun DVB-T2.

Vic xy dng Quy chun k thut tn hiu truyn hnh s mt t (DVB-

T2) l rt cn thit nhm mc ch:

Phc v cho cng tc quy hoch mng truyn hnh s mt t.

Phc v cho cng tc qun l cht lng dch v m bo quyn li ngi s dng dch v.

p ng yu cu n s ha truyn dn pht sng pht thanh truyn hnh.

2.3 Gii hn phm vi xy dng quy chun

Trn c s phn tch l do v mc ch xy dng tiu chun, nhn thy rng vic xy dng quy chun k thut quc gia v tn hiu truyn hnh



hnh s mt t (DVB-T2) ti im thu trong vng ph sng l cn thit v hu ch.

Gii hn phm vi xy dng quy chun: Quy chun c xy dng v chun ha i vi h thng DVB-T2 c nh im thu trn cao.

Tn ca quy chun c xy dng l:

"Quy chun k thut quc gia v tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng"

3. S c xy dng tiu chun

Trn c s nh gi tnh hnh thc tin v s cn thit phi xy dng mt b thng s chun i vi tn hiu truyn hnh s mt t s gip c quan qun l nh nc chuyn ngnh qun l, gim st cht lng dch v truyn hnh s mt t s v cc n v cung cp dch v tham chiu thit k v xy dng mng cung cp dch v. T cc ti liu tham kho, phng php xy dng chun ha cc thng s k thut tn hiu truyn hnh s mt t DVB-T2 ti Vit Nam.B thng s k thut chun ha tn hiu truyn hnh s mt t s s c xy dng gm cc thng s quan trng nht, ti thiu cn thit

m bo cht lng dch v truyn hnh s mt t.Mt s ti liu c tham chiu chnh c th nh sau:

a) Tiu chun ETSI EN 302 755:Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2).

Tiu chun ny c bin son bi Vin cc tiu chun vin thng Chu u ETSI, chun ny hng dn thc hin v gii thch cc thut ng, cc yu cu trong kha cnh truyn dn pht sng tn hiu theo chun DVB-T2.

Tiu chun ny trnh by cc ni dung c bn nh sau:

Tng quan v cng ngh DVB-T2;

X l u vo;

iu ch v m ha bt an xen;



To lp, m ha v iu ch bo hiu lp 1;

B to khung;

To OFDM;

c t v tri ph.

b) Tiu chun TS ETSI102 831 Digital Video Broadcasting (DVB);Implementation guidelines for a second generationdigital terrestrial television broadcasting system (DVB-T2) tiu chun ny hng dn thc hin mt h thng truyn hnh s mt t th h th 2 DVB-T2. Phin bn 1.2.1 ca tiu chun ny c cng b vo thng 8 nm 2011. Cc ch tiu c nh ngha, gii hn c th nh sau:

Tng quan v cng ngh DVB-T2;

La chn cc tham s bao gm: la chn kch thc FFT, la chn cc ch thng thng v ch m rng, la chn khong bo v, La chn pilot pattern, la chn chiu di khung, la chn ch u vo, la chn cc tham s trn thi gian, la chn xoay ca chm sao iu ch, la chn tc m ha, la chn cc ch thch ng;

Phn tch tn hiu DVB-T2;

iu ch giao din v cu hnh mng;

Cc tham s iu ch;

Cc yu cu v my thu tn hiu;

Cc yu cu v truyn dn.

c) Bo coITU RRC-06: Final acts of the Regional Radiocommunication Conference for planning of the digital terrestrial broadcasting service in parts of Regions 1 and 3, in the frequency bands 174-230 MHz and 470-862 MHz.

y l cc cam kt ca cc t chc tham gia hi ngh truyn thng cc

quc gia v dch v truyn hnh s mt t.

Ni dung c bn ca cam kt ny nh sau:

Th tc iu chnh k hoch v th tc phi hp gia cc dch v mt t c bn;



Thng bo v tp tn s;

Gii quyt tranh chp;

Cc ph lc thng nht m cc t chc cam kt tun th nh: Cc k hoch tn s; cc yu t v tiuchunk thutcsdngtrongpht trin k hoch vthc hin cchip nh; Cc c im c bn phi chp nht trong hip nh...

d) Bo co EBU - TECH 3348: Frequency and Network Planning Aspects of DVB-T2

y l bo co ca EBU v quy hoch mng v tn s cho DVB-T2.

Ni dung c bn ca bo co ny nh sau:

Cc thuc tnh ca h thng DVB-T2;

Cc thuc tnh ca b thu, cc tham s v quy hoch mng, kh nng tng thch, kh nng chia s;

Cc Quy hoch mi;

Cc kch bn thc hin;

Cc ph lc tham kho v: Tham s, phng php quy hoch, tiu chun; ngun gc v so snh cc gi tr C/N

e) Bo co ITU-R BT.2254:Frequency and network planningaspects of DVB-T2

Mc ch ca bo co ny l thu thp thng tin lin quan n mng li v quy hoch tn s cho DVB-T2. B sung cc c tnh c thuyt minh trong cc bo co trc ca ETSI EN 302 755, ETSI TS 102 831, v DVB Blue Books[A122, A133]. Bo cao ny bao gm cc ni dung sau:

Khuyn ngh cc thuc tnh ca h thng DVB-T2;

Khuyn ngh cc thuc tnh ca my thu, cc tham s quy hoch mng ;

Cc c tnh mi cn ch khi quy hoch mng;

M phng thc hin mt s kch bn in hnh.



4. Ni dung chnh bn d tho quy chun

4.1 Tn ca quy chun

"Quy chun k thut quc gia v tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng".

4.2 B cc ca tiu chun

Tiu chun c xy dng vi b cc nh sau:

1. QUY NH CHUNG

1.1. Phm vi iu chnh

1.2. i tng p dng

1.3. Gii thch t ng

1.4. K hiu/ Ch vit tt

2. QUY NH K THUT

2.1. Bng tn hot ng

2.2. di tn

2.3. Di thng ca tn hiu

2.4. T s li bit

2.5. T s sng mang trn tp m

2.6. Mc cng trng

3. IU KIN V PHNG PHP O

3.1 iu kin mi trng o

3.2 Thit lp cu hnh o

4. QUY NH V QUN L

5. TRCH NHIM CA T CHC C NHN

6. T CHC THC HIN



PH LC A

A.1. Tnh ton ni suy gi tr t s sng mang trn tp m

A.2. Tnh ton ni suy gi tr cng trng ti thiu

5. Tnh ton xy dng cc ch tiu k thut

5.1 Di tn hot ng

Khong bng tn s dng cho tn hiuDVB-T2 phi tun theo Quyt nh

125/2009/Q-TTg ngy 23 thng 10 nm 2009 ca Th tng Chnh ph v

Quy hoch ph tn s v tuyn in quc gia, cng nh trong d tho thng

t "Quy hoch s dng knh tn s cho truyn hnh mt t bng tn

VHF/UHF n nm 2020" ca B Thng tin v Truyn thng. C th nh

sau:

Trong bng tn VHF c kh nng pht tn hiu vi cc tn s t 174 MHz

n 230 MHz.

Trong bng tn UHF c kh nng pht tn hiu vi cc tn s t 470 MHz

n 790 MHz.

5.2 di tn

di tn c nh ngha l lch ln nht gia tn s tc thi ca tn hiu RF so vi tn s danh nh.

Theo ti liu D-Book Release 3.05 (19 June 2012) Minimum Requirements on the Receiving Equipment for Services in the DVB-T and DVB-T2 Networks di tn c quy nh ti a l 50 kHz so vi tn s danh nh. Ti liu ny l do c quan qun l v vin thng ca Cng ha Sc ban hnh vi mc ch khuyn ngh cho cc doanh nghip cung cp dch v truyn hnh s v cc nh sn xut thit b DVB-T2 trn lnh th ca cng ha Sec. V vy, y l mt ngun ti liu tin cy c th tham kho trong vic xy dng quy chun.

Do , di tn ti a cho php i vi tn hiu DVB-T2 ti im thu trong vng ph song c xc nh trong quy chun ny l 50 kHz



5.3 Di thng ca tn hiu DVB-T2

Trn th gii hin nay chu u n nh di thng cho mi knh l 8MHz,

Bc M n nh 6MHz. i vi Vit Nam chin lc pht trin pht thanh

truyn hnh quy nh s dng mt knh 8MHz cho truyn hnh s, do di

thng ti a ca tn hiu DVB-T2 khng c vt qu 8MHz.

rng bng thng s dng:

7,61 MHz i vi ch thng thng

7,72 MHz i vi ch m rng 8k

7,77 MHz i vi ch m rng 16k v 32k

5.4 T s li bit

T s li bit l thng s c bn xc nh cht lng kt ni truyn dn s; thng s BER l t l s bit li trn tng s bit c truyn.

Trong tiu chun ETSI 102 831 vn v t s li bit c tho lun v mt gi tr BER 10-7 sau m ha LDPC c khuyn ngh p dng, iu ny c th hin bng 44 trang 219 v bng 45 trang 220. gi tr BER 10-7 sau m ha LDPCcng c ITU khuyn ngh trong bo co ca ITU-R-BT.2254 ti bng 2.10 trang 17, bng A.4.1 trang 111, bng A.4.2 trang 112. Do vy t s li bt c xc nh: BER 10-7sau m ha LDPC.

5.5 T s sng mang trn tp m

T s tn hiu trn tp m l t s mt cng sut ph tn hiu ca tn hiu so vi tp m.

Trong bo co ca ITU-R-BT.2254 phn 2.5 trang 13 c a ra yu cu i vi C/N cho cc knh v tuyn in hnh bao gm Knh Guassian, knh Ricean, knh Rayleigh. Tuy nhin i vi phm vi quy chun ny tn hiu DVB-T2 ch c xt cho cc im thu ngoi tri c nh v vy cc tnh ton cho knh Ricean c tham kho. Do , yu cu C/N i vi tn hiu truyn hnh DVB-T2 ti im thu c nh trong vng ph sng c tnh ton c th nh sau:

C/NRice = C/NRice + D C/NRice = C/NGauss-raw + DELTARice +A +B + C



Vi:

C/NRice Gi tr t s sng mang trn tp m knh Rice.

C/NRice Gi tr t s sng mang trn tap m knh Rice c tnh ton

m cha tnh n gi tr tp m bin.

C/NGauss-raw Gi tr C/N th cho knh Gaussian. Gi tr ny c quy nh

c th nh Bng 1.

D Gi tr c thm cho C/N tng ng vi tp m bin ti 33

dBc. Phn c thm vo ti bin l tp m nt iu chnh v

tp m lng t trong b chuyn i tng t sang s c

xc nh ti Bng 2v hnh 1

DELTA H s tng C/N cho knh Rice v knh Rayleigh i vi knh

Gausian. Gi tr DELTARicecho knh Rice nh Bng 3.

A A = 0,1 dB gi tr b sung cho C/N t c BER = 10-7

sau LDPC (c coi l im QEF thch hp cho DVB-T2)

B H s nng cng sut pilot, cc gi tr ca B c cho

biBng 4

C H s nh hng do sai s c lng knh thc, gii m

LDPC v cc vn thc t khc.Gi tr C bng 2,0 dB (PP1-

PP2), 1,5 dB (PP3-PP4), 1,0 dB (PP5-PP7)

Bng 1: Gi tr C/N th cho knh Gaussian (AWGN channel)

Loi iu ch Tc m Knh Gaussian (C/NGauss-raw)

QPSK 1/2 1,0 QPSK 3/5 2,2 QPSK 2/3 3,1 QPSK 3/4 4,1



QPSK 4/5 4,7 QPSK 5/6 5,2

16-QAM 1/2 6,2 16-QAM 3/5 7,6 16-QAM 2/3 8,9 16-QAM 3/4 10,0 16-QAM 4/5 10,8 16-QAM 5/6 11,3 64-QAM 1/2 10,5 64-QAM 3/5 12,3 64-QAM 2/3 13,6 64-QAM 3/4 15,1 64-QAM 4/5 16,1 64-QAM 5/6 16,7

256-QAM 1/2 14,4 256-QAM 3/5 16,7 256-QAM 2/3 18,1 256-QAM 3/4 20,0 256-QAM 4/5 21,3 256-QAM 5/6 22,0

Bng 2: Ch s D, Suy gim C/N, cho cc gi tr C/N t 15 n 32

C/N [dB] D [dB]

15 0,07

16 0,09

17 0,11

18 0,14

19 0,18

20 0,22



21 0,28

22 0,36

23 0,46

24 0,58

25 0,75

26 0,97

27 1,26

28 1,65

28 2,20

30 3,02

31 4,33

32 6,87

Bng cc php m phng, gi tr c th hn i vi ch s D nh hnh 1

Hnh 1: Ch s D, Suy gim C/N cho mc tp m bin -33 dBc

Bng 3: Gi tr DELTA [dB] ca C/N cho knh Rice



Loi iu ch Tc m DELTA C/N Rice (dB)

QPSK 1/2 0,2 QPSK 3/5 0,2 QPSK 2/3 0,3 QPSK 3/4 0,3 QPSK 4/5 0,3 QPSK 5/6 0,4

16-QAM 1/2 0,2 16-QAM 3/5 0,2 16-QAM 2/3 0,2 16-QAM 3/4 0,4 16-QAM 4/5 0,4 16-QAM 5/6 0,4 64-QAM 1/2 0,3 64-QAM 3/5 0,3 64-QAM 2/3 0,3 64-QAM 3/4 0,3 64-QAM 4/5 0,5 64-QAM 5/6 0,4

256-QAM 1/2 0,4 256-QAM 3/5 0,2 256-QAM 2/3 0,3 256-QAM 3/4 0,3 256-QAM 4/5 0,4 256-QAM 5/6 0,4

Bng 4: Cc h s hiu chnh C/N

Pilot Pattern PP1 PP2 PP3 PP4

PP5

PP6

PP7

A 0,1 0,1 0,1 0,1 0,1 0,1 0,1



B 0,4 0,4 0,5 0,5 0,5 0,5 0,3 C 2,0 2,0 1,5 1,5 1,0 1,0 1,0

Vi h thng DVB-T2: PP2 32K 8Mhz GI 1/8 iu kin thu c nh

gi tr C/N c tnh ton nh Bng 5. Bng 5: gi tr C/N yu cu i vi h thng DVB-T2: PP2 32K 8Mhz GI

1/8.

TT Ch iu ch

s

T l m sa

sai

Knh thu a ng c tnh n nhiu nhit, pha thu c nh (Rice)

1 QPSK 1/2 3,7 2 QPSK 3/5 4,9 3 QPSK 2/3 5,9 4 QPSK 3/4 6,9 5 QPSK 4/5 7,5 6 QPSK 5/6 8,1 7 16QAM 1/2 8,9 8 16QAM 3/5 10,3 9 16QAM 2/3 11,6 10 16QAM 3/4 12,9 11 16QAM 4/5 13,8 12 16QAM 5/6 14,4 13 64QAM 1/2 13,3 14 64QAM 3/5 15,2 15 64QAM 2/3 16,5 16 64QAM 3/4 18,0 17 64QAM 4.5 19,3 18 64QAM 5/6 19,8 19 256QAM 1/2 17,4 20 256QAM 3/5 19,6



21 256QAM 2/3 21,2 22 256QAM 3/4 23,2 23 256QAM 4.5 24,8 24 256QAM 5/6 25,6

5.6 Mc cng trng trung bnh ti thiu

c nh ngha l gi tr ca cng trng ti thiu cho php pha thu t c cht lng thu mong mun ti im thu c nh trong vng ph sng truyn hnh DVB-T2 (tnh bng dBV/m). H thng truyn hnh s DVB-T2 phi c gi tr mc cng trng ti thiu khng nh hn gi tr tng ng vi cc ch iu chv t l m sa sai khc nhau ca h thng truyn hnh s DVB-T2trong iu kin thu c nh. Vi bng tn VHF xc nh ti tn s 200 MHz v vi bng tn UHFxc nh ti tn s 650MHz yu cu i vi mc cng trng ti thiu khng c thp hn gi tr quy nh ti bng sau.

Bng 6: Gi tr cng trng ti thiu (dBV/m)

TT

Ch iu ch

s

T l m sa li hng pht

Tn s (MHz) C/N Emed

1 QPSK 2/3 200 5,9 27,7 2 16QAM 2/3 200 11,6 33,4 3 64QAM 2/3 200 16,5 38,3 4 256QAM 2/3 200 21,2 43,0 5 QPSK 2/3 650 5,9 34,0 6 16QAM 2/3 650 11,6 39,7 7 64QAM 2/3 650 16,5 44,6 8 256QAM 2/3 650 21,2 49,3

i vi cc ch , cc knh tn s khc ca h thng DVB-T2, yu cu i mc tn hiu DVB-T2 ti im thu trong vng ph sng c th c ni suy nh sau:

Emed= med + 120 + 10 log10 (120) = med + 145.8



med = min + Pmmn + Cl min = Ps min Aa + Lf Aa = G + 10 log (1.642/4 ) Ps min = C/N + Pn Pn = F + 10 log (k T0 B)

Vi: Emed Mc cng ng trng tng ng ti thiu (dBV/m)

med Mt cng sut trung bnh ti thiu (dBW/m2)

min Mt cng sut ti thiu ti im thu (dBW/m2)

Pmmn H s b nhiu do cc tc nhn nhn to (dB), gi tr Pmmnc

cho bi Bng 7 v Bng 8

Cl H s hiu chnh v tr (dB). Gi tr ca Cl xem ti cng thc

di.

Ps min Cng sut u vo my thu ti thiu (dBW) (Tham kho theo

d tho quy chun quc gia v thit b gii m (Set top box)

trong mng truyn hnh s mt t (ang c son tho, sp

ban hnh))

Aa Khu n ten hiu dng (dBm2).

Lf Suy hao do feeder (dB). Gi tr c th xem tiBng 9

G li ca anten (dBd). Gi tr li antena i vi cc bng

tn khc nhau c th nh Bng 10

Bc sng ca sng mang tn hiu (m). Gi tr c th quy i

t tn s ca sng mang tn hiu

Pn Cng sut nhiu u vo my thu (dBW).

C/N T s sng mang trn tp m. Gi tr c th ni suy theo cng



thc mc 5.5

F Tp m my thu (dB). Gi tr tp m my thu c ITU

khuyn ngh l 6 dB trong ITU-R-BT.2254 (Trc EBU

khuyn ngh gi tr tp m my thu l 7dB)

k Hng s Boltzmann (k = 1,38 1023 (J/K))

T0 Nhit tuyt i (T0 = 290 (K))

B tp m bng thng my thu (B = 7,61 106 (Hz) i vi mi

bng thng 8MHz ch thng thng, B = 7,71 106 (Hz)

i vi mi bng thng 8 MHz ch m rng 8k v B = 7,77

106 (Hz) i vi mi bng thng 8 MHz ch m rng 16k

v 32k)

H s hiu chnh v tr c tnh theo cng thc:

C1 = t Vi :

: H s phn phi bng 0.52 cho 70%; 1.28 cho 90%; 1.64 cho 95% v 2.33 cho 99%.

t : lch chun c gi tr l 5,5 dB i vi im thu c nh ngoi tri.

Bng 7: H s b nhiu do cc tc nhn nhn to ti khu vc th

Khu vc th Bng III Bng IV/ bng V

Gi tr i vi antena tch hp lin

quan 0 dB 0 dB

Gi tr i vi antena ngoi 1 dB 0 dB

Gi tr i vi antena trn mi 2 dB 0 dB

Gi tr i vi antena thch nghi 8 dB 1 dB



Bng 8: H s b nhiu do cc tc nhn nhn to ti khu vc nng thn

Khu vc nng thn Bng III Bng IV/ bng V

Gi tr i vi antena tch hp lin

quan 0 dB 0 dB

Gi tr i vi antena ngoi 0 dB 0 dB

Gi tr i vi antena trn mi 2 dB 0 dB

Gi tr i vi antena thch nghi 5 dB 0 dB

Bng 9: Suy hao feeder cho cc bng tn khc nhau.

Suy hao feeder (dB) Band III Band IV/V Ch thu

Antena c nh trn mi 2 4 Thu c nh trn mi

Bng 10: li antena i vi cc bng tn khc nhau

li ca antena (dBd)

Band III Bands IV/V Ch thu

Antena c nh trn mi 7 11 Thu c nh trn mi



Bng i chiu ni dung QCVN v ti liu tham kho.

Quy chun k thut quc gia v tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sng

Ti liu tham kho Sa i, b sung

1. Quy nh chung 1.1. Phm vi iu chnh T xy dng 1.2. i tng p dng T xy dng 1.3. Gii thch t ng

1.3.1. Tn hiu s Theo QCVN 31:2011/BTTTT mc 1.4.21

Chp nhn nguyn vn

1.3.2. Truyn hnh s T xy dng



mt t th h th hai 1.3.3. Doanh nghip cung cp dch v truyn hnh

TCVN-8688:2011 Chp nhn nguyn vn

1.3.4. Thu bao (ngi s dng dch v) TCVN-8688:2011

Chp nhn nguyn vn

1.3.5. Phng php xc nh TCVN-8688:2011

Chp nhn nguyn vn

1.3.6.im thu c nh trong vng ph sng truyn hnh s mt t

T xy dng

1.3.7. iu kin thu c nh

ITU-RRC06 mc 3.4.3 trang 168 Tham kho

1.3.8. Mc cng trng trung bnh ti thiu Emed

RRC06 Anex 3.2 trang 185.

Tham kho

1.3.9. Di tn s hot ng T xy dng

1.3.10. Di thng ca mi knh TCVN-8688:2011 Vin dn

1.3.11. di tn T xy dng 1.3.12. T s li bit TCVN-8688:2011 Vin dn 1.3.13. T s sng mang trn tp m TCVN-8688:2011 Vin dn

1.4. K hiu/ Ch vit tt T xy dng

2. Quy nh k thut

2.1. Di tn hot ng

ITU-R-BT.2254 mc 2.1 trang 8. Quyt nh 125/2009/Q-TTg

Tham kho tng hp.

2.2. di tn D-Book - Minimum Requirements on the Receiving Equipment for

Tham kho tng hp.



Services in the DVB-T and DVB-T2 Networks

2.3. Di thng ca mi knh truyn hnh DVB-T2

ETSI 302 755 Bng 66 trang 116. ITU-R-BT.2254 mc 2.1 trang 8

Tham kho tng hp.

2.4. T s li bit ITU-R-BT.2254 bng 2.10 trang 17, bng A.4.1 trang 111, bng A.4.2 trang 112

Tham kho tng hp

2.6. T s sng mang trn tp m

ITU-R-BT.2254 mc 2.5 trang 13

Tham kho tng hp

Bng 1: gi tr C/N yu cu i vi h thng DVB-T2: PP2 32K 8Mhz GI 1/8.

Tham kho ITU-R-BT.2254 - TABLE 2.14: C/N QEF valid for DVB-T2 PP2 32k normal BW GI 1/8 Trang 20

Tng hp la chn cc gi tr cho knh Rice

2.6. Mc cng trng ti thiu Emed

ITU-R-BT.2254 mc 3.3 trang 35

Bng 2: Gi tr cng trng ti thiu.

Bng tnh ton mc cng trng cho DVB-T2 bng III v bng IV/V

Tham kho, tng hp

3. iu kin v phng php o

3.1. iu kin mi trng

QCVN 51:2011/BTTTT Trang 6 mc 2.2.3.1

Tham kho

3.2. Phng php o T xy dng Ph lc A (quy nh) A.1. Tnh ton ni suy gi tr t s sng mang trn tp m

Cng thc: C/NRice = C/NRice + D C/NRice = C/NGauss-raw + DELTARice +A +B + C

Tham kho ITU-R-BT.2254 trang 19.

Chp nhn nguyn vn



Bng A.1.1: Gi tr C/N th cho knh Gaussian (AWGN channel)

Tham kho ITU-R-BT.2254 - TABLE 2.9Raw C/N values for a Gaussian Channel(AWGN channel)

Chp nhn nguyn vn

Bng A.1.2: Ch s D, Suy gim C/N, cho cc gi tr C/N t 15 n 32

Tham kho ITU-R-BT.2254 - TABLE 2.11:Factor D, C/N degradation as table for C/N values from 15 to 32 Trang 17.

Chp nhn nguyn vn

Hnh A.1: Ch s D, Suy gim C/N cho mc tp m bin -33 dBc

Tham kho ITU-R-BT.2254 - FIGURE 2.2: Factor D, C/N degradation for a back-stop noise level of 33 dBc,

Chp nhn nguyn vn

Bng A.1.3: Gi tr DELTA [dB] ca C/N cho knh Rice

Tham kho ITU-R-BT.2254 - TABLE 2.13: Increase DELTA (dB) of C/N for Rice and static Rayleigh channelswith regard to Gaussian channel

Chn lc gi tr cho knh Rice

Bng A.1.4: Cc h s hiu chnh C/N

Tham kho ITU-R-BT.2254 - TABLE 2.10Averaged C/N correction factors

Chp nhn nguyn vn

A.2. Tnh ton ni suy gi tr cng trng ti thiu

Cng thc: Emed= med + 120 + 10 log10 (120) = med + 145.8

Tham kho ITU-T-BT.2254 trang 92

Chp nhn nguyn vn

Cng thc: Tham kho ITU-T-BT.2254 trang 92 (for Chp nhn nguyn vn



med = min + Pmmn + Cl

fixed reception)

Cng thc: min = Ps min Aa + Lf


Chp nhn nguyn vn

Cng thc: Aa = G + 10 log (1.642/4 )

Tham kho ITU-T-BT.2254 trang 91 trong mc gii thch gi tr Aa

Chp nhn nguyn vn

Cng thc: Ps min = C/N + Pn


Chp nhn nguyn vn

Cng thc: Pn = F + 10 log (k T0 B)


Chp nhn nguyn vn

Cng thc:

C1 = t Tham kho ITU-T-BT.2254 trang 92

Chp nhn nguyn vn

Bng A.2.1: H s b nhiu do cc tc nhn nhn to ti khu vc th

Tham kho ITU-T-BT.2254 - TABLE A1.3:Allowance for man-made noise used in the calculation for urban areas Trang 94

Chp nhn nguyn vn

Bng A.2.2: H s b nhiu do cc tc nhn nhn to ti khu vc nng thn

Tham kho ITU-T-BT.2254 -TABLE A1.4: Allowance for man-made noise used in the calculation for rural areas Trang 95

Chp nhn nguyn vn

Bng A.2.3: Suy hao feeder cho cc bng tn khc nhau

Tham kho ITU-T-BT.2254 -TABLE A1.2: Feeder loss in dB for the different bands Trang 93

Chp nhn nguyn vn

Bng A.2.4 li antena i vi cc bng tn khc nhau

Tham kho ITU-T-BT.2254 -TABLE A1.1: Antenna gain in dBd for the different bands and for

Chp nhn nguyn vn



the different reception modes Trang 93.

TI LIU THAM KHO [1] ETSI EN 302 755 v1.3.1 (04/2012) : Digital Video Broadcasting (DVB);

Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2)

[2] ETSI TR 101 290 v1.2.1 (05/2001): Digital Video Broadcasting (DVB); Measurement guidelines for DVB systems

[3] ETSI TS 102 831 v1.2.1 (08/2012): Digital Video Broadcasting (DVB); Implementation guidelines for a second generation digital terrestrial television broadcasting system (DVB-T2).

[4] DVB Document A114 (04/2007): Commerical Requirement for DVB-T2. [5] ITU RRC-06: Final acts of the Regional Radiocommunication Conference

for planning of the digital terrestrial broadcasting service in parts of Regions 1 and 3, in the frequency bands 174-230 MHz and 470-862 MHz.

[6] EBU-TECH3348 v2.0 (05/2012): Frequency and Network Planning Aspects of DVB-T2.

[7] ITU-R-BT.2254 (09/2012) Frequency and network planning aspects of DVB-T2

[8] D-Book Minimum Requirements on the Receiving Equipment for Services in the DVB-T and DVB-T2 Networks - Release 3.05 (19 June 2012)

[9] Digital Video Broadcasting (DVB); Implementation guiderlines for a second generation digital terrestrial television broadcasting system (DVB-T2).

[10] ITU-T J.193 (06-2004): Requirements for the next generation of set-top-boxes

[11] IEC - 61883-1 (03-2001), Consumer audio/video equipment - Digital Interface - Part 1: General

[12] ETSI EN 300 - 468 V1.6.1: Digital Video Broadcasting (DVB): Specification for Service Information (SI) in DVB systems

[13] ETSI EN 300 - 743 V1.2.1: Digital Video Broadcasting (DVB): Subtitling Systems



[14] ETSI ES 201 - 488 -1, -2, - 3 V1.1.1: Data over cable system; Part 1: General; Part 2: Radio Frequency Interface Specification; Part 3: Baseline Privacy Plus Interface Specificatio

[15] ETSI TS 102 - 006 V1.3.1: Digital Video Broadcasting (DVB): Specification for System Software Update in DVB Systems

[16] ETSI TS 102 - 201 V1.1.1: Digital Video Broadcasting (DVB): Interfaces for DVB Integrated Receiver Decoder (DVB-IRD)

[17] Tiu chun quc gia v thit b Set Top Box (STB) trong mng truyn hnh s mt t s dng k thut s - Yu cu k thut 2010.

[18] Quy chun k thut Quc gia v ph tn v tng thch in t i vi thit b pht hnh qung b mt t s dng k thut DVB-T.

[19] Understanding digital tv (ROVER laboratories).

Documents

68_thuyetminh