B BU CHNH VIN THNG
Thuyt minh d tho quy chun
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 GIAV TN HIU TRUYN HNH S MT T (DVB-T2) TI IM THU TRONG VNG PH SNGH NI, THNG 09-2012MC LC
11.Tn gi v k hiu quy chun
12.t vn
12.1 Tnh hnh tiu chun ha
82.2 L do v mc ch xy dng tiu chun
82.3 Gii hn phm vi xy dng tiu chun
93.S c xy dng tiu chun
114.Ni dung chnh bn d tho quy chun
114.1 Tn ca quy chun
124.2 B cc ca tiu chun
135.Tnh ton xy dng cc ch tiu k thut
135.1 Di tn hot ng
135.2 di tn
135.3 Di thng ca tn hiu DVB-T2
145.4 T s li bit
145.5 T s sng mang trn tp m
205.6 Mc cng trng trung bnh ti thiu
1. Tn gi quy chunTn 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 1.1 Tnh hnh tiu chun haa) 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 ITUITU 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 televisionservices 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.1.2 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.1.3 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 chunTrn 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 trink 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 chun4.1 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 32k5.4 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/NRiceGi tr t s sng mang trn tp m knh Rice.
C/NRiceGi tr t s sng mang trn tap m knh Rice c tnh ton m cha tnh n gi tr tp m bin.
C/NGauss-rawGi tr C/N th cho knh Gaussian. Gi tr ny c quy nh c th nh Bng 1.
DGi 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
DELTAH s tng C/N cho knh Rice v knh Rayleigh i vi knh Gausian. Gi tr DELTARicecho knh Rice nh Bng 3.
AA = 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)
BH s nng cng sut pilot, cc gi tr ca B c cho biBng 4
CH 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 chTc mKnh Gaussian (C/NGauss-raw)
QPSK1/21,0
QPSK3/52,2
QPSK2/33,1
QPSK3/44,1
QPSK4/54,7
QPSK5/65,2
16-QAM1/26,2
16-QAM3/57,6
16-QAM2/38,9
16-QAM3/410,0
16-QAM4/510,8
16-QAM5/611,3
64-QAM1/210,5
64-QAM3/512,3
64-QAM2/313,6
64-QAM3/415,1
64-QAM4/516,1
64-QAM5/616,7
256-QAM1/214,4
256-QAM3/516,7
256-QAM2/318,1
256-QAM3/420,0
256-QAM4/521,3
256-QAM5/622,0
Bng 2: Ch s D, Suy gim C/N, cho cc gi tr C/N t 15 n 32
C/N [dB]D [dB]
150,07
160,09
170,11
180,14
190,18
200,22
210,28
220,36
230,46
240,58
250,75
260,97
271,26
281,65
282,20
303,02
314,33
326,87
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 chTc mDELTA C/N Rice (dB)
QPSK1/20,2
QPSK3/50,2
QPSK2/30,3
QPSK3/40,3
QPSK4/50,3
QPSK5/60,4
16-QAM1/20,2
16-QAM3/50,2
16-QAM2/30,2
16-QAM3/40,4
16-QAM4/50,4
16-QAM5/60,4
64-QAM1/20,3
64-QAM3/50,3
64-QAM2/30,3
64-QAM3/40,3
64-QAM4/50,5
64-QAM5/60,4
256-QAM1/20,4
256-QAM3/50,2
256-QAM2/30,3
256-QAM3/40,3
256-QAM4/50,4
256-QAM5/60,4
Bng 4: Cc h s hiu chnh C/NPilot PatternPP1PP2PP3PP4PP5PP6PP7
A0,10,10,10,10,10,10,1
B0,40,40,50,50,50,50,3
C2,02,01,51,51,01,01,0
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.
TTCh iu ch sT l m sa saiKnh thu a ng c tnh n nhiu nhit, pha thu c nh (Rice)
1QPSK1/23,7
2QPSK3/54,9
3QPSK2/35,9
4QPSK3/46,9
5QPSK4/57,5
6QPSK5/68,1
716QAM1/28,9
816QAM3/510,3
916QAM2/311,6
1016QAM3/412,9
1116QAM4/513,8
1216QAM5/614,4
1364QAM1/213,3
1464QAM3/515,2
1564QAM2/316,5
1664QAM3/418,0
1764QAM4.519,3
1864QAM5/619,8
19256QAM1/217,4
20256QAM3/519,6
21256QAM2/321,2
22256QAM3/423,2
23256QAM4.524,8
24256QAM5/625,6
5.6 Mc cng trng trung bnh ti thiuc 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 (dB(V/m)
TTCh iu ch sT l m sa li hng phtTn s (MHz)C/NEmed
1QPSK2/32005,927,7
216QAM2/320011,633,4
364QAM2/320016,538,3
4256QAM2/320021,243,0
5QPSK2/36505,934,0
616QAM2/365011,639,7
764QAM2/365016,544,6
8256QAM2/365021,249,3
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 + 145.8med = 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:
EmedMc cng ng trng tng ng ti thiu (dBV/m)
medMt cng sut trung bnh ti thiu (dBW/m2)
minMt cng sut ti thiu ti im thu (dBW/m2)
PmmnH s b nhiu do cc tc nhn nhn to (dB), gi tr Pmmnc cho bi Bng 7 v Bng 8
ClH s hiu chnh v tr (dB). Gi tr ca Cl xem ti cng thc di.
Ps minCng 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))
AaKhu n ten hiu dng (dBm2).
LfSuy 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
PnCng sut nhiu u vo my thu (dBW).
C/NT s sng mang trn tp m. Gi tr c th ni suy theo cng thc mc 5.5
FTp 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)
kHng s Boltzmann (k = 1,38 1023 (J/K))
T0Nhit tuyt i (T0 = 290 (K))
Btp 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= ((tVi :
:H s phn phi bng 0.52 cho 70%; 1.28 cho 90%; 1.64 cho 95% v2.33 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 thBng IIIBng IV/ bng V
Gi tr i vi antena tch hp lin quan0 dB0 dB
Gi tr i vi antena ngoi1 dB0 dB
Gi tr i vi antena trn mi2 dB0 dB
Gi tr i vi antena thch nghi 8 dB1 dB
Bng 8: H s b nhiu do cc tc nhn nhn to ti khu vc nng thn
Khu vc nng thnBng IIIBng IV/ bng V
Gi tr i vi antena tch hp lin quan0 dB0 dB
Gi tr i vi antena ngoi0 dB0 dB
Gi tr i vi antena trn mi2 dB0 dB
Gi tr i vi antena thch nghi 5 dB0 dB
Bng 9: Suy hao feeder cho cc bng tn khc nhau.
Suy hao feeder (dB)
BandIIIBandIV/VCh thu
Antena c nh trn mi24Thu c nh trn mi
Bng 10: li antena i vi cc bng tn khc nhau
li ca antena (dBd)Ch thu
BandIIIBandsIV/V
Antena c nh trn mi711Thu 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 sngTi liu tham khoSa i, b sung
1. Quy nh chung
1.1. Phm vi iu chnhT xy dng
1.2. i tng p dngT xy dng
1.3. Gii thch t ng
1.3.1. Tn hiu sTheo QCVN 31:2011/BTTTT mc 1.4.21Chp nhn nguyn vn
1.3.2. Truyn hnh s mt t th h th haiT xy dng
1.3.3. Doanh nghip cung cp dch v truyn hnhTCVN-8688:2011Chp nhn nguyn vn
1.3.4. Thu bao (ngi s dng dch v)TCVN-8688:2011Chp nhn nguyn vn
1.3.5. Phng php xc nh TCVN-8688:2011Chp nhn nguyn vn
1.3.6.im thu c nh trong vng ph sng truyn hnh s mt tT xy dng
1.3.7. iu kin thu c nhITU-RRC06 mc 3.4.3 trang 168Tham kho
1.3.8. Mc cng trng trung bnh ti thiu EmedRRC06 Anex 3.2 trang 185.
Tham kho
1.3.9. Di tn s hot ngT xy dng
1.3.10. Di thng ca mi knhTCVN-8688:2011Vin dn
1.3.11. di tnT xy dng
1.3.12. T s li bitTCVN-8688:2011Vin dn
1.3.13. T s sng mang trn tp mTCVN-8688:2011Vin dn
1.4. K hiu/ Ch vit ttT xy dng
2. Quy nh k thut
2.1. Di tn hot ngITU-R-BT.2254 mc 2.1 trang 8.
Quyt nh 125/2009/Q-TTgTham kho tng hp.
2.2. di tnD-Book - Minimum Requirements on the Receiving Equipment for Services in the DVB-T and DVB-T2 NetworksTham kho tng hp.
2.3. Di thng ca mi knh truyn hnh DVB-T2ETSI 302 755 Bng 66 trang 116.
ITU-R-BT.2254 mc 2.1 trang 8Tham kho tng hp.
2.4. T s li bitITU-R-BT.2254 bng 2.10 trang 17, bng A.4.1 trang 111, bng A.4.2 trang 112Tham kho tng hp
2.6. T s sng mang trn tp mITU-R-BT.2254 mc 2.5 trang 13Tham 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 20Tng hp la chn cc gi tr cho knh Rice
2.6. Mc cng trng ti thiu EmedITU-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/VTham kho, tng hp
3. iu kin v phng php o
3.1. iu kin mi trngQCVN 51:2011/BTTTT
Trang 6 mc 2.2.3.1Tham kho
3.2. Phng php oT 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 32Tham 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 dBcTham 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 RiceTham kho ITU-R-BT.2254 - TABLE 2.13: Increase DELTA (dB) of C/N for Rice and static Rayleigh channelswith regard to Gaussian channelChn lc gi tr cho knh Rice
Bng A.1.4: Cc h s hiu chnh C/NTham kho ITU-R-BT.2254 - TABLE 2.10Averaged C/N correction factorsChp 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 92Chp nhn nguyn vn
Cng thc:
med = min + Pmmn + Cl
Tham kho ITU-T-BT.2254 trang 92 (for fixed reception)Chp nhn nguyn vn
Cng thc:
min = Ps min Aa + Lf
Tham kho ITU-T-BT.2254 trang 91Chp 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 AaChp nhn nguyn vn
Cng thc:
Ps min = C/N + PnTham kho ITU-T-BT.2254 trang 34Chp nhn nguyn vn
Cng thc:
Pn = F + 10 log (k T0 B)Tham kho ITU-T-BT.2254 trang 34Chp nhn nguyn vn
Cng thc:
C1= ((tTham kho ITU-T-BT.2254 trang 92Chp nhn nguyn vn
Bng A.2.1: H s b nhiu do cc tc nhn nhn to ti khu vc thTham kho ITU-T-BT.2254 - TABLE A1.3:Allowance for man-made noise used in the calculation for urban areas Trang 94Chp nhn nguyn vn
Bng A.2.2: H s b nhiu do cc tc nhn nhn to ti khu vc nng thnTham kho ITU-T-BT.2254 -TABLE A1.4: Allowance for man-made noise used in the calculation for rural areas Trang 95Chp nhn nguyn vn
Bng A.2.3: Suy hao feeder cho cc bng tn khc nhauTham kho ITU-T-BT.2254 -TABLE A1.2: Feeder loss in dB for the different bands Trang 93Chp nhn nguyn vn
Bng A.2.4 li antena i vi cc bng tn khc nhauTham kho ITU-T-BT.2254 -TABLE A1.1: Antenna gain in dBd for the different bands and for the different reception modes Trang 93.Chp nhn nguyn vn
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 settopboxes
[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).
16Tn hiu truyn hnh s mt t (DVB-T2) ti im thu trong vng ph sngTrang 22
