regional information meeting and workshop related to the rrc-06 for the administrations of the...
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Regional Information Meeting and Workshop related to the Regional Information Meeting and Workshop related to the RRC-06 for the administrations of the African countriesRRC-06 for the administrations of the African countries
Dakar, Senegal, 25-29 April 2005Dakar, Senegal, 25-29 April 2005
Planning for DVB-T and T-DAB services
Some practical considerations
Pham Nhu HaiRadiocommunication Bureau
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
OutlineOutline
Digital world!Policy objectivesPlanning objectivesPlanning methodology
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Digital world!Digital world!
DVB-T and T-DAB based on completely different techniques– Large number of carriers– Several programs bundled into
multiplexes. Each multiplex• T-DAB: 6 to 8 programs• DVB-T: 2 to 4 PAL equivalent programs
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Digital world!!Digital world!!
Brick wall reception effect (4 to 1: 2dB)
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Digital world!!!Digital world!!!
Reception modes– Fixed– Portable indoor– Portable outdoor–Mobile
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Digital world!!!Digital world!!!
Single Frequency networks (SFN)
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Policy decisions - examplesPolicy decisions - examples
Conversions– Can all broadcasters convert?– Same coverage between digital and analogue?– Simulcast? How long?
Competition– New players in the market– How many? – When new licences issued?
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Policy decisions – more examplesPolicy decisions – more examples
Equalisation– Same number of services throughout
the country?–More in urban centres?
Spectrum for other uses–Which parts of the frequency bands?–When and How?
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Planning objectives?Planning objectives?
Simulcast of analogue and digitalDigital = analogue coverage as soon
as possiblePortable reception modes in urban
centers and fixed for outskirt areasQuality of service – High definition?Number of services
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Frequency bands?Frequency bands?
174-230 MHz– DVB-T and T-DAB– T-DAB only– DVB-T only–Mixed TV channel spacing
470-862 MHz–Whole bands– Part of the bands
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Which reception mode?Which reception mode?
DVB-T– Fixed– Portable outdoor and indoor– Mobile– Main population – portable– Outlying areas - Fixed
T-DAB– Mobile – Portable indoor
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
DVB-T system variants?DVB-T system variants?
Fixed reception– 64QAM and 2/3 code rate 1/8 guard interval– 16QAM and 2/3 code rate 1/8 guard interval
Mobile reception– 8K QPSK 2/3 rate and ¼ guard interval– 2K 16QAM ½ rate and ¼ guard interval
Use RPCs
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Network structure?Network structure?
Multi Frequency Network (MFN)Single Frequency Network (SFN)
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Multi frequency network MFNMulti frequency network MFN
Each transmitter operates on a different frequency
Overlaps between transmitters possible
Regional or local programmingIdeal for conversion of existing
analogue services
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Single frequency network SFNSingle frequency network SFN
All transmitters operates on the same frequency and carry the same program
Ideal for national or large regional networks
Low power transmitters can be added if required
Most suited for mobile networks
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Planning criteriaPlanning criteria
Minimise interference and disruption to analogue services
Minimise cost to viewers and broadcasters– Use of existing transmitting facilities– Consideration of existing receive
antennasIdentify a minimum of N channels
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
One planning approachOne planning approach
Determine minimum median field strength– System variants– Reception mode
Determine ERP required to provide desired coverage– Propagation models– Tx site– Receive antenna
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
One planning approach..One planning approach..
Calculate available protection ratioAPR=W-U+AD+PDWhere• W: wanted signal level (dBuV/m)• U: unwanted signal level (dBuV/m)• AD: antenna directivity (dB)• PD: polarisation discrimination (dB)
Use knowledge from existing analogue situation
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
One planning approach…One planning approach…
Determine available channels from comparing Required vs Available protection ratio
Eliminate other channels because of other possible interference mechanisms– Local oscillator– Image
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
ConclusionsConclusions
Clear planning objectivesNational planning <> RRC planningConsideration of existing
transmitting and receive facilitiesUse experience from the operation of
analogue servicesCarry out tests if necessary
RRC information meeting and workshop
Dakar, Senegal 25-29 April 2005
Thanks for your attentionThanks for your attention