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